SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Keita Åsa) "

Sökning: WFRF:(Keita Åsa)

  • Resultat 1-50 av 86
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Al-Saffar, Anas Kh. 1969- (författare)
  • Gastrointestinal Permeability and Motility in Inflammatory Bowel Disease
  • 2019
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Synchronized motility, permeability and secretory (hormones and enzymes) events are integral to normal physiology. Smooth muscle syncytium operates with enteric nervous system (ENS) and endocrine signalling to accommodate, mix and control passage of ingested materials. The intestinal epithelial cells (IECs) drive digestion and absorption while repelling harmful compounds.This thesis investigated GI barrier function (permeability, mucosal integrity), motility and hormonal patterns in inflammatory bowel disease (IBD) by: 1) assessing GI motility using a wireless motility capsule (WMC, SmartPill®) and video capsule endoscopy (VCE, Pillcam®), 2) investigation of intestinal fatty acid binding protein (I-FABP) as a biomarker of Crohn’s disease (CD) disease activity, 3) evaluation of small intestinal permeability in IBD, 4) investigating meal-related WMC motility and simultaneous hormonal (e.g., Ghrelin, GLP-1, GIP, PYY) patterns in IBD. Reference WMC motility values for transit times for gastric emptying, small bowel, orocecal, small+large bowel, colon and whole gut were established. Software-generated estimates and visually determined values were nearly identical. Compared with VCE estimates (represents fasting conditions), the WMC records longer GET and SBTT. Variations in intra-subject reproducibility must be considered in clinical investigations. This data was then used to investigate IBD patients. I-FABP was primarily expressed in the epithelium of the small bowel and to lesser extent also in the colon and stomach. Circulating I-FABP was elevated in active CD with a magnitude comparable to TNFα. I-FABP lowers and rises again in parallel with TNFα and HBI during infliximab treatment. I-FABP can be used as a jejunum and ileum selective prognostic biomarker for monitoring disease activity. Increased small intestine mucosal barrier permeability to lactulose in both CD and UC was found. Sucralose can serve a dual purpose in quantifying small and large intestinal permeability. Small intestinal hyper-permeability was not revealed as a transporter dependent nutrient (riboflavin) malabsorption. Using the WMC, consistent motility disturbances in IBD were limited, as were differences in pH. However, disturbances within many individuals were found. As part of the investigation, defects in gut peptide and metabolic hormone meal responses were found, typically higher plasma levels. No clear associations between hormones and motility were found. Effects on hunger/satiety signaling in IBD are anticipated.The present thesis shows the utility of the WMC and gut barrier tests in monitoring IBD patients.
  •  
2.
  • Alkaissi, Lina Y., et al. (författare)
  • Antagonism of Adherent Invasive E. coli LF82 With Human α-defensin 5 in the Follicle-associated Epithelium of Patients With Ileal Crohn’s Disease
  • 2021
  • Ingår i: Inflammatory Bowel Diseases. - : OXFORD UNIV PRESS INC. - 1078-0998 .- 1536-4844. ; 27:7, s. 1116-1127
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The first visible signs of Crohns disease (CD) are microscopic erosions over the follicle-associated epithelium (FAE). The aim of the study was to investigate the effects of human alpha-defensin 5 (HD5) on adherent-invasive Escherichia coli LF82 translocation and HD5 secretion after LF82 exposure in an in vitro model of human FAE and in human FAE ex vivo. Methods: An in vitro FAE-model was set up by the coculture of Raji B cells and Caco-2-cl1 cells. Ileal FAE from patients with CD and controls were mounted in Ussing chambers. The effect of HD5 on LF82 translocation was studied by LF82 exposure to the cells or tissues with or without incubation with HD5. The HD5 secretion was measured in human FAE exposed to LF82 or Salmonella typhimurium. The HD5 levels were evaluated by immunofluorescence, immunoblotting, and ELISA. Results: There was an increased LF82 translocation across the FAE-model compared with Caco-2-cl1 (P < 0.05). Incubation of cell/tissues with HD5 before LF82 exposure reduced bacterial passage in both models. Human FAE showed increased LF82 translocation in CD compared with controls and attenuated passage after incubation with sublethal HD5 in both CD and controls (P < 0.05). LF82 exposure resulted in a lower HD5 secretion in CD FAE compared with controls (P < 0.05), whereas Salmonella exposure caused equal secretion on CD and controls. There were significantly lower HD5 levels in CD tissues compared with controls. Conclusions: Sublethal HD5 reduces the ability of LF82 to translocate through FAE. The HD5 is secreted less in CD in response to LF82, despite a normal response to Salmonella. This further implicates the integrated role of antimicrobial factors and barrier function in CD pathogenesis.
  •  
3.
  • Bednarska, Olga, et al. (författare)
  • A postbiotic fermented oat gruel may have a beneficial effect on the colonic mucosal barrier in patients with irritable bowel syndrome
  • 2022
  • Ingår i: Frontiers in Nutrition. - : FRONTIERS MEDIA SA. - 2296-861X. ; 9
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Impaired intestinal permeability and microbial dysbiosis are important pathophysiological mechanisms underlying irritable bowel syndrome (IBS). ReFerm (R)( ), also called Profermin (R), is a postbiotic product of oat gruel fermented with Lactobacillus plantarum 299v. In this study, we investigated whether ReFerm (R) has a beneficial effect on the intestinal epithelial barrier function in patients with IBS.Materials and methods: Thirty patients with moderate to severe IBS-diarrhoea (IBS-D) or IBS-mixed (IBS-M) were treated with enema containing ReFerm (R) or placebo. The patients underwent sigmoidoscopy with biopsies obtained from the distal colon at baseline and after 14 days of treatment with ReFerm (R) or placebo twice daily. The biopsies were mounted in Ussing chambers, and paracellular and transcellular permeabilities were measured for 120 min. In addition, the effects of ReFerm (R) or placebo on the epithelial barrier were investigated in vitro using Caco-2 cells.Results: ReFerm (R) reduced paracellular permeability (p < 0.05) and increased transepithelial resistance (TER) over time (p < 0.01), whereas the placebo had no significant effect in patients. In ReFerm (R)-treated Caco-2 cells, paracellular and transcellular permeabilities were decreased compared to the control (p < 0.05) and placebo (p < 0.01). TER was increased in Caco-2 ReFerm (R)-treated cells, and normalised TER was increased in ReFerm (R)-treated Caco-2 cells compared to control (p < 0.05) and placebo-treated (p < 0.05) cells.Conclusion: ReFerm (R) significantly reduced paracellular permeability and improved TER in colonic biopsies collected from patients with IBS and in a Caco-2 cell model. Our results offer new insights into the potential benefits of ReFerm (R) in IBS management. Further studies are needed to identify the molecular mechanisms underlying the barrier-protective properties of ReFerm (R).
  •  
4.
  • Bednarska, Olga, 1973- (författare)
  • Peripheral and Central Mechanisms in Irritable Bowel Syndrome : in search of links
  • 2019
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Irritable bowel syndrome (IBS) is a chronic visceral pain disorder with female predominance, characterized by recurrent abdominal pain and disturbed bowel habits in the absence of an identifiable organic cause. This prevalent and debilitating disease, which accounts for a substantial economic and individual burden, lacks exact diagnostic tools and effective treatment, since its pathophysiology remains uncertain. The bidirectional and multilayered brain-gut axis is a well-established disease model, however, the interactions between central and peripheral mechanisms along the brain-gut axis remain incompletely understood. One of the welldescribed triggering factors, yet accounting for only a fraction of IBS prevalence, is bacterial gastroenteritis that affects mucosal barrier function. Altered gut microbiota composition as well as disturbed intestinal mucosal barrier function and its neuroimmune regulation have been reported in IBS, however, the impact of live bacteria, neither commensal nor pathogenic, on intestinal barrier has not been studied yet. Furthermore, abnormal central processing of visceral sensations and psychological factors such as maladaptive coping have previously been suggested as centrally-mediated pathophysiological mechanisms of importance in IBS. Brain imaging studies have demonstrated an imbalance in descending pain modulatory networks and alterations in brain regions associated with interoceptive awareness and pain processing and modulation, particularly in anterior insula (aINS), although biochemical changes putatively underlying these central alterations remain poorly understood. Most importantly, however, possible associations between these documented changes on central and peripheral levels, which may as complex interactions contribute to disease onset and chronification of symptoms, are widely unknown.This thesis aimed to investigate the peripheral and central mechanisms in women with IBS compared to female healthy controls (HC) and to explore possible mutual associations between these mechanisms.In Paper I, we studied paracellular permeability and passage of live bacteria, both commensal and pathogenic through colonic biopsies mounted in Ussing chambers. We explored the regulation of the mucosal barrier function by mast cells and the neuropeptide vasoactive intestinal polypeptide (VIP) as well as a correlation between mucosal permeability and gastrointestinal and psychological symptoms. We observed increased paracellular permeability and the passage of commensal and pathogenic live bacteria in patients with IBS compared with HC, which was diminished by blocking the VIP receptors as well as after stabilizing mast cells in both groups. Moreover, higher paracellular permeability was associated with less somatic and psychological symptoms in patients.In Paper II, we aimed to determine the association between colonic mucosa paracellular permeability and structural and resting state functional brain connectivity. We demonstrated different patterns of associations between mucosa permeability and functional and structural brain connectivity in IBS patients compared to HC. Specifically, lower paracellular permeability in IBS, similar to the levels detected in HC, was associated with more severe IBS symptoms and increased functional and structural connectivity between intrinsic brain resting state network and descending pain modulation brain regions. Our findings further suggested that this association between mucosa permeability and functional brain connectivity was mainly mediated by coping strategies.In Paper III, we investigated putative alterations in excitatory and inhibitory neurotransmission of aINS, as the brain’s key node of the salience network crucially involved in cognitive control, in IBS patients relative to HC and addressed possible connections with both symptoms and psychological factors. We found decreased concentrations of the excitatory neurotransmitter Glx in bilateral aINS in IBS patients compared to HC, while inhibitory neurotransmitter GABA+ levels were comparable. Further, we demonstrated hemisphere-specific associations between abdominal pain, coping and aINS excitatory neurotransmitter concentration.In conclusion, this thesis broadens the knowledge on peripheral and central mechanisms in IBS and presents novel findings that bring together the ends of brain-gut axis. Our results depict association between mucosal permeability, IBS symptoms and functional and structural connectivity engaging brain regions involved in emotion and pain modulation as well as underlying neurotransmitter alterations.
  •  
5.
  • Bednarska, Olga, et al. (författare)
  • Vasoactive Intestinal Polypeptide and Mast Cells Regulate Increased Passage of Colonic Bacteria in Patients With Irritable Bowel Syndrome
  • 2017
  • Ingår i: Gastroenterology. - : W B SAUNDERS CO-ELSEVIER INC. - 0016-5085 .- 1528-0012. ; 153:4, s. 948-
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND amp; AIMS: Irritable bowel syndrome (IBS) is associated with intestinal dysbiosis and symptoms of IBS develop following gastroenteritis. We aimed to study the passage of live bacteria through the colonic epithelium, and determine the role of mast cells (MCs) and vasoactive intestinal polypeptide (VIP) in barrier regulation in IBS and healthy individuals. METHODS: Colon biopsies from 32 women with IBS and 15 age-matched healthy women (controls) were mounted in Ussing chambers; we measured numbers of fluorescently labeled Escherichia coli HS and Salmonella typhimurium that passed through from the mucosal side to the serosal side of the tissue. Some biopsies were exposed to agents that block the VIP receptors (VPAC1 and VPAC2) or MCs. Levels of VIP and tryptase were measured in plasma and biopsy lysates. Number of MCs and MCs that express VIP or VIP receptors were quantified by immunofluorescence. Biopsies from an additional 5 patients with IBS and 4 controls were mounted in chambers and Salmonella were added; we studied passage routes through the epithelium by transmission electron microscopy and expression of tight junctions by confocal microscopy. RESULTS: In colon biopsies from patients with IBS, larger numbers of E coli HS and S typhimurium passed through the epithelium than in biopsies from controls (P amp;lt;.0005). In transmission electron microscopy analyses, bacteria were found to cross the epithelium via only the transcellular route. Bacterial passage was reduced in biopsies from patients with IBS and controls after addition of antibodies against VPACs or ketotifen, which inhibits MCs. Plasma samples from patients with IBS had higher levels of VIP than plasma samples from controls. Biopsies from patients with IBS had higher levels of tryptase, larger numbers of MCs, and a higher percentage of MCs that express VPAC1 than biopsies from controls. In biopsies from patients with IBS, addition of Salmonella significantly reduced levels of occludin; subsequent addition of ketotifen significantly reversed this effect. CONCLUSIONS: We found that colonic epithelium tissues from patients with IBS have increased translocation of commensal and pathogenic live bacteria compared with controls. The mechanisms of increased translocation include MCs and VIP.
  •  
6.
  • Beeckmans, Dorien, et al. (författare)
  • Relationship between bile salts, bacterial translocation, and duodenal mucosal integrity in functional dyspepsia
  • 2020
  • Ingår i: Neurogastroenterology and Motility. - : WILEY. - 1350-1925 .- 1365-2982. ; 32:5
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Functional dyspepsia (FD) is a complex disorder, in which multiple mechanisms underlie symptom generation, including impaired duodenal barrier function. Moreover, an altered duodenal bile salt pool was recently discovered in patients with FD. We aimed to evaluate the relationship between bile salts, bacterial translocation, and duodenal mucosal permeability in FD. Methods Duodenal biopsies from patients with FD and healthy volunteers (HV) were mounted in Ussing chambers to measure mucosal resistance and bacterial passage in the absence and presence of fluorescein-conjugated Escherichia coli and glyco-ursodeoxycholic acid (GUDCA) exposure. In parallel, duodenal fluid aspirates were collected from patients and bile salts were analyzed. Key results The transepithelial electrical resistance of duodenal biopsies from patients was lower compared with HV (21.4 +/- 1.3 omega.cm(2) vs. 24.4 +/- 1.2 omega.cm(2); P = .02; N = 21). The ratio of glyco-cholic and glyco-chenodeoxycholic acid (GCDCA) to tauro- and GUDCA correlated positively with transepithelial electrical resistance in patients. Glyco-ursodeoxycholic acid slightly altered the mucosal resistance, resulting in similar values between patient and healthy biopsies (22.1 +/- 1.0 omega.cm(2) vs. 23.0 +/- 1.0 omega.cm(2); P = .5). Bacterial passage after 120 minutes was lower for patient than for healthy biopsies (0.0 [0.0-681.8] vs. 1684.0 [0.0-4773.0] E coli units; P = .02). Glyco-ursodeoxycholic acid increased bacterial passage in patient biopsies (102.1 [0.0-733.0] vs. 638.9 [280.6-2124.0] E coli units; P = .009). No correlation was found between mucosal resistance and bacterial passage. Conclusions amp; inferences Patients with FD displayed decreased duodenal mucosal resistance associated with bile salts, however, not associated with bacterial passage in vitro. In addition, the hydrophilic bile salt glyco-ursodeoxycholic acid abolished differences in mucosal resistance and bacterial passage between patient and control group.
  •  
7.
  • Bergemalm, Daniel, 1977-, et al. (författare)
  • Systemic Inflammation in Preclinical Ulcerative Colitis
  • 2021
  • Ingår i: Gastroenterology. - : AGA Institute. - 0016-5085 .- 1528-0012. ; 161:5, s. 1526-1539.e9
  • Tidskriftsartikel (refereegranskat)abstract
    • Background & Aims: Preclinical ulcerative colitis is poorly defined. We aimed to characterize the preclinical systemic inflammation in ulcerative colitis, using a comprehensive set of proteins.Methods: We obtained plasma samples biobanked from individuals who developed ulcerative colitis later in life (n = 72) and matched healthy controls (n = 140) within a population-based screening cohort. We measured 92 proteins related to inflammation using a proximity extension assay. The biologic relevance of these findings was validated in an inception cohort of patients with ulcerative colitis (n = 101) and healthy controls (n = 50). To examine the influence of genetic and environmental factors on these markers, a cohort of healthy twin siblings of patients with ulcerative colitis (n = 41) and matched healthy controls (n = 37) were explored.Results: Six proteins (MMP10, CXCL9, CCL11, SLAMF1, CXCL11 and MCP-1) were up-regulated (P < .05) in preclinical ulcerative colitis compared with controls based on both univariate and multivariable models. Ingenuity Pathway Analyses identified several potential key regulators, including interleukin-1β, tumor necrosis factor, interferon-gamma, oncostatin M, nuclear factor-κB, interleukin-6, and interleukin-4. For validation, we built a multivariable model to predict disease in the inception cohort. The model discriminated treatment-naïve patients with ulcerative colitis from controls with leave-one-out cross-validation (area under the curve = 0.92). Consistently, MMP10, CXCL9, CXCL11, and MCP-1, but not CCL11 and SLAMF1, were significantly up-regulated among the healthy twin siblings, even though their relative abundances seemed higher in incident ulcerative colitis.Conclusions: A set of inflammatory proteins are up-regulated several years before a diagnosis of ulcerative colitis. These proteins were highly predictive of an ulcerative colitis diagnosis, and some seemed to be up-regulated already at exposure to genetic and environmental risk factors.
  •  
8.
  • Bhattacharya, Pradyot, et al. (författare)
  • Complement opsonization of HIV affects primary infection of human colorectal mucosa and subsequent activation of T cells
  • 2020
  • Ingår i: eLIFE. - Cambridge, United Kingdom : ELIFE SCIENCES PUBLICATIONS LTD. - 2050-084X. ; 9
  • Tidskriftsartikel (refereegranskat)abstract
    • HIV transmission via genital and colorectal mucosa are the most common routes of dissemination. Here, we explored the effects of free and complement-opsonized HIV on colorectal tissue. Initially, there was higher antiviral responses in the free HIV compared to complementopsonized virus. The mucosal transcriptional response at 24 hr revealed the involvement of activated T cells, which was mirrored in cellular responses observed at 96 hr in isolated mucosal T cells. Further, HIV exposure led to skewing of T cell phenotypes predominantly to inflammatory CD4+ T cells, that is Th17 and Th1Th17 subsets. Of note, HIV exposure created an environment that altered the CD8+ T cell phenotype, for example expression of regulatory factors, especially when the virions were opsonized with complement factors. Our findings suggest that HIV-opsonization alters the activation and signaling pathways in the colorectal mucosa, which promotes viral establishment by creating an environment that stimulates mucosal T cell activation and inflammatory Th cells.
  •  
9.
  • Biskou, Olga, et al. (författare)
  • Increased Numbers of Enteric Glial Cells in the Peyers Patches and Enhanced Intestinal Permeability by Glial Cell Mediators in Patients with Ileal Crohns Disease
  • 2022
  • Ingår i: Cells. - Basel, Switzerland : MDPI. - 2073-4409. ; 11:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Enteric glial cells (EGC) are known to regulate gastrointestinal functions; however, their role in Crohns disease (CD) is elusive. Microscopic erosions over the ileal Peyers patches are early signs of CD. The aim of this work was to assess the localization of EGC in the follicle and interfollicular region of the Peyers patches and in the lamina propria and study the effects of EGC mediators on barrier function in CD patients and non-inflammatory bowel disease (non-IBD) controls. EGC markers, glial fibrillary acidic protein (GFAP), and S100 calcium-binding protein β (S100β) were quantified by immunofluorescence and Western blotting. Both markers showed significantly more EGC in the Peyers patches and lamina propria of CD patients compared to the non-IBD controls. In CD patients there were significantly more EGC in Peyers patches compared to lamina propria, while the opposite pattern was seen in controls. Barrier function studies using Ussing chambers showed increased paracellular permeability by EGC mediators in CD patients, whereas permeability decreased by the mediators in controls. We show the accumulation of EGC in Peyers patches of CD patients. Moreover, EGC mediators induced barrier dysfunction in CD patients. Thus, EGC might have harmful impacts on ongoing inflammation and contribute to the pathophysiology of the disease.
  •  
10.
  • Biskou, Olga, et al. (författare)
  • ReFerm®: a postbiotic fermented oat gruel composition is reducing mast cell degranulation in the colon of patients with irritable bowel syndrome
  • 2024
  • Ingår i: Frontiers in Medicine. - : FRONTIERS MEDIA SA. - 2296-858X. ; 11
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder that affects similar to 4% of the global population. ReFerm((R)) is a postbiotic product derived from oat gruel fermented with Lactobacillus plantarum 299v, and it has been shown to have beneficial effects on intestinal permeability in patients with IBS. In this study, we investigated the effects of ReFerm((R)) on regulators of intestinal permeability, namely mast cells and enteric glial cells. Materials and methods: A total of 30 patients with moderate to severe IBS were treated with an enema containing ReFerm((R)) or a placebo twice daily. The patients underwent sigmoidoscopy with biopsies obtained from the distal colon at baseline and after 14 days of treatment. These biopsies were processed in two ways: some were fixed, embedded in paraffin, sectioned, and stained for mast cells and enteric glial cells; others were cryopreserved, lysed, and subjected to Western blotting to analyze the same markers. Results: Treatment with ReFerm((R)), but not the placebo, significantly reduced mast cell tryptase protein levels in the biopsy lysates. Although the number of mast cells remained unchanged in colonic biopsies, ReFerm((R)) treatment significantly reduced mast cell degranulation, a result not observed in the placebo group. Neither ReFerm((R)) or placebo treatment had an impact on total protein levels or the number of enteric glial cells in the biopsies. Conclusion: ReFerm((R)) treatment significantly reduced both total mast cell tryptase levels and the degranulation of mast cells in colonic biopsies from patients with IBS, suggesting a decrease in mast cell activity as a potential mechanism underlying the beneficial effects of ReFerm((R)). However, further research is required to assess the molecular mechanisms through which ReFerm((R)) operates in the colons of patients with IBS.
  •  
11.
  • Carlander, J, et al. (författare)
  • Comparison of experimental nerve injury caused by ultrasonically activated scalpel and electrosurgery.
  • 2005
  • Ingår i: The British journal of surgery. - : Oxford University Press (OUP). - 0007-1323 .- 1365-2168. ; 92:6, s. 772-7
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Iatrogenic nerve injury caused by heat from dissection instruments is a significant problem in many areas of surgery. The aim of the present study was to compare the risk of nerve injury for three different dissection instruments: monopolar and bipolar electrosurgery (ES) and an ultrasonically activated (US) instrument. METHODS: The biceps femoris muscle was cut in a standard manner just adjacent to the sciatic nerve using monopolar ES, bipolar ES or US shears. A total of 73 functional experiments were conducted in which the nerve was isolated, divided proximally, and stimulated supramaximally in 37 anaesthetized rats. The electromyographic (EMG) potential was recorded distally before and after each experiment. Nerve dysfunction was defined as more than 10 per cent loss of the evoked EMG potential. Fifty-nine nerves were examined histologically after dissection with the different instruments. The extent of heat damage was determined in four nerves that were divided with ES bipolar scissors and five that were divided with US shears. RESULTS: Reduction in the EMG potential was significantly more frequent in the monopolar ES group than in the US group. Morphological examination also showed significantly less nerve damage in the US group. CONCLUSION: US instruments may be safer than ES for dissection close to nerves.
  •  
12.
  • Carlsson, Anders, 1980- (författare)
  • Role of mast cells and probiotics in the regulation of intestinal barrier function
  • 2013
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The intestinal mucosa is the largest contact area and one of the most important barriers to the outside environment. It is highly specialized in aiding us digest and absorb nutrients. It is daily exposed to several potentially dangerous substances and microorganisms, which if they were allowed to pass into the body, could give rise to diseases. Throughout the small intestine certain sites specialized in antigen sampling are found. These sites are named Peyer’s patches and are lymphoid follicles. The epithelium covering the Peyer’s patches is called follicle-associated epithelium and is specialized in antigen sampling and uptake. The special epithelium enables presentation of luminal antigen to immune cells in the underlying follicle.Persistent life stress and stressful life events affect the course of irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) through largely unknown mechanisms. Regulation of epithelial permeability to antigens is crucial for the balance between inflammation and immune-surveillance, and increased intestinal permeability has been shown in patients with ulcerative colitis and Crohns disease. Vasoactive intestinal polypeptide (VIP) and corticotropin-releasing factor have been implicated as important mediators of stress-induced abnormalities in intestinal mucosal functions in animal models. Both of these mediators have been reported to regulate bowel ion secretion in humans during stress and uptake of horseradish peroxidase in rodents. Probiotics have been shown to ameliorate the deleterious effects of stress on intestinal function, but mechanisms remain to be elucidated.The aim of this thesis was to elucidate whether mast cells play an important role in intestinal barrier function during stress and inflammation. Moreover, we wanted to determine whether probiotics can ameliorate the mucosal barrier integrity during stress and inflammation.To study the function of mast cells we conducted in vitro experiments on cell lines and ex vivo experiments in Ussing chambers on mouse, rat and human intestinal tissue. The Ussing chamber technique measures electrophysiological properties of the tissue and also gives the possibility to study transcellular and paracellular passage of markers and bacteria. Immunohistology and confocal microscopy have been used to identify mast cells and receptors of interest.Our results show that stress affects the follicle-associated epithelium barrier by mechanisms involving VIP and mast cells. These findings were corroborated by the localization of VIP receptors on mucosal mast cells. Furthermore, pretreatment with probiotics was effective in protecting the gut against stress-induced intestinal barrier dysfunction and mucosal inflammation. This protection appeared to involve a mast cell and peroxisome proliferatoractivated receptor-γ dependent mechanism.
  •  
13.
  • Casado-Bedmar, Maite, et al. (författare)
  • Elevated F-EDN correlates with mucosal eosinophil degranulation in patients with IBS : A possible association with microbiota?
  • 2022
  • Ingår i: Journal of Leukocyte Biology. - : Alan R. Liss Inc.. - 0741-5400 .- 1938-3673. ; 111:3, s. 655-665
  • Tidskriftsartikel (refereegranskat)abstract
    • Eosinophils have been linked to functional dyspepsia; however, less is known about their role in irritable bowel syndrome (IBS). This study tested the hypothesis of alterations in levels of fecal eosinophil-derived neurotoxin (F-EDN) and eosinophil density and degranulation within the colonic mucosa of IBS patients compared with healthy controls (HC). Colonic biopsies were collected from 37 IBS patients and 20 HC and analyzed for eosinophil numbers and local degranulation of eosinophil cationic protein (ECP) by histologic procedures. Fecal samples were collected for F-EDN and microbiota analysis. Differentiated 15HL-60 cells were used in vitro to investigate the direct effect of live bacteria on eosinophil activation measured by a colorimetric assay with o-phenylenediamine (OPD) substrate. We observed a higher number of eosinophils and increased extracellular ECP in the mucosa of IBS patients compared with HC. Moreover, F-EDN levels in IBS samples were elevated compared with HC and positively correlated to extracellular ECP. Metagenomic analysis showed significant correlations between bacterial composition and eosinophil measurements in both HC and IBS patients. In vitro experiments revealed an increased degranulation of 15HL-60 after stimulation with Salmonella typhimurium, Salmonella enterica, and Yersinia enterocolitica. To conclude, we could demonstrate alterations related to eosinophils in IBS, and, for the first time, a positive correlation between F-EDN levels and degranulated eosinophils in the colonic mucosa of IBS patients. Together our results suggest that eosinophils play a role in the pathophysiology of IBS and the mechanisms might be linked to an altered microbiota.
  •  
14.
  • Casado Bedmar, Maite, et al. (författare)
  • Potential neuro-immune therapeutic targets in irritable bowel syndrome
  • 2020
  • Ingår i: Therapeutic Advances in Gastroenterology. - : Sage Publications. - 1756-283X .- 1756-2848. ; 13
  • Forskningsöversikt (refereegranskat)abstract
    • Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder characterized by recurring abdominal pain and disturbed bowel habits. The aetiology of IBS is unknown but there is evidence that genetic, environmental and immunological factors together contribute to the development of the disease. Current treatment of IBS includes lifestyle and dietary interventions, laxatives or antimotility drugs, probiotics, antispasmodics and antidepressant medication. The gut-brain axis comprises the central nervous system, the hypothalamic pituitary axis, the autonomic nervous system and the enteric nervous system. Within the intestinal mucosa there are close connections between immune cells and nerve fibres of the enteric nervous system, and signalling between, for example, mast cells and nerves has shown to be of great importance during GI disorders such as IBS. Communication between the gut and the brain is most importantly routed via the vagus nerve, where signals are transmitted by neuropeptides. It is evident that IBS is a disease of a gut-brain axis dysregulation, involving altered signalling between immune cells and neurotransmitters. In this review, we analyse the most novel and distinct neuro-immune interactions within the IBS mucosa in association with already existing and potential therapeutic targets.
  •  
15.
  • Casado Bedmar, Maria Teresa, 1990- (författare)
  • Neuro-immuno-regulation of inflammation in the colonic mucosa : Focus on mast cells and eosinophils in bowel disorders
  • 2020
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Intestinal homeostasis is key to control uptake across the mucosa and protect from harmful substances. Disturbances in the bidirectional communication between the gut and the brain are implicated in irritable bowel syndrome (IBS) and inflammatory bowel diseases (IBD), being Crohn’s disease (CD) and ulcerative colitis (UC) the two most common IBD subtypes. Although these chronic bowel-relapsing inflammatory disorders present different histopathology, they share similar pathological features. Both IBS and IBD are characterized by a disrupted intestinal barrier function, a pro-inflammatory chronic condition, and an altered gut-brain axis. Despite all the scientific effort, the sequence or exact combination of events that drive these diseases are still unknown, and so is the exact role of every single component. Growing evidence suggests altered neuro-immune interactions as a pathogenic factor.The general aim of this thesis was to elucidate the potential involvement of mast cells and eosinophils in IBS and IBD, and the neuro-immune intercellular circuit via vasoactive intestinal polypeptide (VIP) that might exacerbate mucosal inflammation and intestinal barrier disruption.Intestinal tissues from IBS, inactive IBD, healthy controls (HC), and murine colitis were collected. Electrophysiological and permeability studies were performed using the ex vivo Ussing chamber technique. Tissues were processed with immunohistological procedures to study cell numbers, activation, location, and interactions in relation to VIP.We demonstrated for the very first time an increased transcellular passage of live commensal and pathogenic bacteria through the colonic mucosa of IBS, identifying VIP as a key regulatory molecule together with mast cells activation. In vitro experiments revealed the ability of VIP to activate mast cells. Image analysis identified VIP-mast cells in closer proximity in IBD patients and murine colitis compared to controls. Communication between mast cells and VIP was shown upregulated in IBD and mice colitis via VIP receptor (VPAC)1. Similarities and differences between HC, IBS, and IBD were further studied. Results indicated a pronounced increased intestinal permeability in UC, even during remission, followed by IBS, compared to healthy controls. Surprisingly, permeability results did not correlate with mast cells, but with eosinophil number and activation. A further image analysis suggested an inhibitory effect of eosinophils and VIP on mast cells and an altered interaction between them under inflammatory conditions. Lastly, intestinal VIP levels were shown to increase in IBD patients after the treatment with biological agents and were suggested as a possible biomarker for biological treatment outcome.This thesis presents novel insights into the regulation of intestinal permeability, as well as into the pathophysiology of IBD and IBS by demonstrating the importance of neuro-immune interactions between mast cells, VIP, and eosinophils.Altogether, our findings have broadened the knowledge of neuro-immune interactions in IBS and IBD and might have the potential to onsight lead to new therapeutic approaches thereby improving the outcomes for patients suffering from these diseases.
  •  
16.
  • Casado Bedmar, Maria Teresa, et al. (författare)
  • Upregulation of intestinal mucosal mast cells expressing VPAC1 in close proximity to vasoactive intestinal polypeptide in inflammatory bowel disease and murine colitis
  • 2019
  • Ingår i: Neurogastroenterology and Motility. - : Wiley-Blackwell Publishing Inc.. - 1350-1925 .- 1365-2982. ; 31:3
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundMast cells (MCs) and vasoactive intestinal polypeptide (VIP) have been proposed as regulators of the intestinal barrier and inflammation. Our aim was to map the distribution in inflammatory bowel disease (IBD) and murine colitis.MethodsMCs, VIP, and VIP‐receptors (VPACs) were quantified by immunofluorescence and enzyme‐immunoassay (EIA) in ileal tissues (villus epithelium (VE) and adjacent VE, ie, VE next to the follicle‐associated epithelium, (FAE)) from Crohn's disease (CD; n = 16) and non‐IBD patients, and in colonic specimens of ulcerative colitis (UC; n = 12) and healthy controls (HCs). In addition, VIP levels were measured in plasma from HCs, non‐IBD, and IBD in remission (CD n = 30; UC n = 30). Colon, ileum, and plasma from mice with dextran sulfate sodium (DSS)‐induced colitis and control mice were analyzed likewise.Key ResultsFAE‐adjacent VE in ileum of CD possessed more MCs (P < 0.05) and MCs expressing VPAC1 (P < 0.05), but not VPAC2, compared to controls. Both adjacent and regular VE of CD had more MCs co‐localizing/in close proximity to VIP (P < 0.05). In UC colon, more MCs (P < 0.0005), MCs close to VIP (P < 0.0005), and MCs expressing VPAC1 (P < 0.05) were found compared to controls. VIP levels were elevated in plasma from CD and UC compared to controls (P < 0.0005). Colon of DSS mice showed more MCs and MCs close to VIP (P < 0.05) compared to control mice. In vitro experiments revealed MCs expressing VPACs and internalized VIP after 120 minutes of VIP‐stimulation.Conclusions and InferencesCommunication between MCs and VIP is upregulated during IBD and mice colitis. In CD patients, the epithelium next to FAE seems to be more involved than the surrounding VE, suggesting increased MC‐VIP‐interactions in this intestinal region.
  •  
17.
  • Christerson, Ulrika, 1970-, et al. (författare)
  • Group IIA secretory phospholipase A2 (sPLA2- IIA) and group V secretoryphospholipase A2 (sPLA2-V) in the human mast cell line HMC-1
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • Background: Mast cells (MC) are considered to be major effector cells in the pathophysiology of Crohn´s disease (CD). The variety of agents released from activated MC includes secretory phospholipase A2s (sPLA2s), small enzymes known to have both autocrine and paracrine actions of potential importance in inflammatory conditions. The expression of protease-activated receptor-2 (PAR-2) is increased on ileal mucosal MC in CD, however it is not known if this receptor influences the release of sPLA2s from MC. Despite extensive studies in rodent MC, not much is known about sPLA2s in human MC. The principle aims of this study were to investigate if the human mast cell line HMC-1 could serve as a model for studies on two sPLA2s implicated in inflammation, namely sPLA2-IIA and sPLA2-V, and if stimulation of PAR-2 influences the release of the two enzymes.Methods: HMC-1 cells were used for studies on sPLA2 expression by RT-PCR and immunocytochemistry. Degranulation and sPLA2 release was investigated by β-hexosaminidase assay and ELISA, respectively. sPLA2 expression in ileal CD specimens was investigated by immunohistochemistry. Results: In HMC-1 cells the basal expression of sPLA2-IIA seemed to be more pronounced than of sPLA2-V but only sPLA2-V was induced by TNF-α. A23187, but not the PAR-2 stimulator trypsin, caused release of the two enzymes. Both sPLA2-IIA and -V were detected in ileal MC of the CD specimens, but sPLA2-IIA seemed to be more abundant. Conclusions: HMC-1 cells express both sPLA2-IIA and sPLA2-V but the expression may bedifferently regulated by inflammatory cytokines. HMC-1 cells release sPLA2-IIA and sPLA2-V upon appropriate stimulation, although not by PAR-2 stimulation. These results make HMC-1 promising as a model for studies on these two enzymes in human MC. Indeed, the finding that both sPLA2-IIA and sPLA2-V are present in ileal MC in CD strengthens the relevance of such a model.
  •  
18.
  • Christerson, Ulrika, et al. (författare)
  • Increased expression of protease-activated receptor-2 in mucosal mast cells in Crohn's ileitis
  • 2009
  • Ingår i: Journal of Crohn's & Colitis. - : Oxford University Press (OUP). - 1873-9946 .- 1876-4479. ; 3:2, s. 100-108
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and aimsActivation of protease-activated receptor-2 (PAR-2) may stimulate various events of importance in inflammatory processes, including release of inflammatory mast cell mediators. PAR-2 is frequently up-regulated during inflammatory conditions, but it is not known if the expression is altered in Crohn's disease. The aim of the present study was to investigate the ileal mucosal PAR-2 expression in Crohn's ileitis, with particular emphasis on the expression in ileal mucosal mast cells.MethodsSurgical specimens from the distal ileum were collected from patients with Crohn's ileitis and patients with colonic cancer as controls. The overall expression of PAR-2 was investigated by Western blot, and the presence of PAR-2 expressing mucosal mast cells by immunohistochemistry and cell counting. The effect of tumor necrosis factor-α (TNF-α) on the PAR-2 expression in a human mast cell line (HMC-1) was investigated by RT-PCR and immunocytochemistry.ResultsIn Crohn's specimens, the fraction of PAR-2-expressing mucosal mast cells was increased about 2.5 times (P < 0.001; n = 14) compared with specimens from control patients (n = 6). No difference was found between inflamed (n = 6) and uninflamed Crohn's specimens (P > 0.05; n = 8). Exposure to TNF-α for 48 h up-regulated PAR-2 mRNA and protein expression in the HMC-1 cell line.ConclusionPAR-2 is up-regulated on ileal mucosal mast cells in Crohn's ileitis, possibly due to the action of inflammatory cytokines, such as TNF-α. This may contribute to perpetuating the inflammatory process in the intestinal mucosa in Crohn's ileitis.
  •  
19.
  • Christerson, Ulrika, 1970-, et al. (författare)
  • Possible Involvement of Intracellular Calcium-Independent Phospholipase A(2) in the Release of Secretory Phospholipases from Mast Cells-Increased Expression in Ileal Mast Cells of Crohn's Disease
  • 2019
  • Ingår i: Cells. - : MDPI. - 2073-4409. ; 8:7, s. 1-15
  • Tidskriftsartikel (refereegranskat)abstract
    • Increased activity of secretory phospholipases A(2) (sPLA(2)) type-II was previously observed in ileum of Crohn's disease (CD). Our aims were to explore the involvement of calcium-independent (i)PLA(2 beta) in the release of sPLA(2)s from the human mast cell (MC) line (HMC-1) and investigate expressions of cytosolic (c)PLA(2) alpha, iPLA(2)beta, sPLA(2)-IIA and sPLA(2)-V in MCs of CD ileum. The release of sPLA(2) was investigated in HMC-1 by immunocytochemistry and ELISA. The expression intensities of PLA(2)s in mucosal MCs, and the proportion of PLA(2)-positive MCs, were investigated in normal ileum and in ileum from patients with CD by immunohistochemistry. The calcium ionophore-stimulated release of sPLA(2)-IIA and sPLA(2)-V from HMC-1 was reduced by the iPLA(2)-inhibitor bromoenol lactone. All four PLA(2)s were detectable in mucosal MCs, both in normal ileum and in CD, but the proportion of iPLA(2)beta-containing mucosal MCs and the expression intensity of sPLA(2)-IIA was increased in CD. Results indicate that iPLA(2)beta is involved in the secretion of sPLA(2)s from HMC-1, and suggest that iPLA(2)beta-mediated release of sPLA(2) from intestinal MCs may contribute to CD pathophysiology. Ex vivo studies on isolated mucosal mast cells are however needed to clarify the precise role of MC PLA(2)s in the inflammatory processes of CD.
  •  
20.
  • Christerson, Ulrika, et al. (författare)
  • Potential role of protease-activated receptor-2-stimulated activation of cytosolic phospholipase A2 in intestinal myofibroblast proliferation : Implications for stricture formation in Crohn´s disease
  • 2009
  • Ingår i: Journal of Crohn's & Colitis. - : Oxford University Press (OUP). - 1873-9946 .- 1876-4479. ; 3:1, s. 15-24
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and aimsMyofibroblast hyperplasia contributes to muscularis mucosae thickening and stricture formation in Crohn's disease (CD). Protease-activated receptor-2 (PAR-2) and cytosolic phospholipase A2 (cPLA2) are known regulators of cell growth, but their significance in intestinal myofibroblast proliferation remain to be elucidated. The principle aims of the present study were to investigate if PAR-2 is expressed in the expanded muscularis mucosa in ileal CD specimens, if inflammatory cytokines may stimulate PAR-2 expression in intestinal myofibroblasts, and if PAR-2 and cPLA2 may regulate intestinal myofibroblast growth.MethodsImmunohistochemistry was used for detection of PAR-2 in ileal CD specimens. Studies on PAR-2 expression, PLA2 activation and cell growth were performed in a human intestinal myofibroblast cell line, CCD-18Co. PAR-2 expression was investigated by RT-PCR and immunocytochemistry. PLA2 activity was analyzed by quantification of released 14C-arachidonic acid (14C-AA). Cell growth was examined by 3H-thymidine incorporation and cell counting.ResultsThe thickened muscularis mucosae of the CD specimens showed strong PAR-2 expression. In cultured myofibroblasts, tumor necrosis factor-α (TNF-α) up-regulated PAR-2 mRNA and protein, and potentiated PAR-2-stimulated 14C-AA release by two known PAR-2 activators, trypsin and SLIGRL-NH2. The release of 14C-AA was dependent on cPLA2. Trypsin stimulated the proliferation of serum-starved cells, and inhibition of cPLA2 reduced normal cell growth and abolished the growth-promoting effect of trypsin.ConclusionsThe results suggest that PAR-2-mediated cPLA2 activation might be of importance in intestinal myofibroblast proliferation. The results also point to the possibility that PAR-2 up-regulation by inflammatory cytokines, like TNF-α, may modulate this effect.     
  •  
21.
  • Da Silva, Stéphanie, et al. (författare)
  • A novel topical PPARγ agonist induces PPARγ-activity in ulcerative colitis mucosa and prevents and reverses inflammation in induced-colitis models
  • 2018
  • Ingår i: Inflammatory Bowel Diseases. - : Lippincott Williams & Wilkins. - 1078-0998 .- 1536-4844. ; 24:4, s. 792-805
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Peroxisome proliferator-activated receptor-gamma (PPARγ) exerts anti-inflammatory effects and is therefore a potential target in ulcerative colitis (UC). A novel PPARγ agonist (AS002) developed for local action was evaluated ex vivo in biopsies from UC patients and in vivo in mice with low-grade dextran sodium sulfate (DSS)- and trinitrobenzene sulfonic acid (TNBS)-induced colitis.Methods: Colonic biopsies from UC patients (n = 18) and healthy controls (n = 6) were incubated with AS002 or rosiglitazone (positive control) to measure mRNA expression of the PPARγ-responsive gene ADIPOPHILIN and protein levels of UC-related cytokines (enzyme-linked immunosorbent assay). AS002 absorption was determined in the colonic mucosa of UC patients. DSS-colitis mice received PPARγ agonists or vehicle daily by intrarectal administration starting 2 days before induction of colitis (preventive) or from days 3 to 8 (curative). Myeloperoxidase (MPO) and cytokine levels in colonic mucosa were determined. In addition, AS002 effects were studied in TNBS colitis.Results: AS002 displayed an absorption pattern of a lipophilic drug totally metabolized in the mucosa. AS002 and rosiglitazone increased ADIPOPHILIN mRNA expression (3-fold) and decreased TNF-α, IL-1β, and IL-13 levels in human UC biopsies. In DSS, in both preventive and curative treatment and in TNBS colitis, AS002 protected against macroscopic and histological damage and lowered MPO and TNF-α, IL-1β, and IL-13 levels.Conclusions: AS002 triggers anti-inflammatory PPARγ activity in the human colonic mucosa of UC patients and prevents and reverses colitis in mice. Our data suggest that AS002 has potential for topical maintenance treatment of UC, which warrants further studies in vivo in patients.
  •  
22.
  • Ermund, Anna, et al. (författare)
  • Mucus properties and goblet cell quantification in mouse, rat and human ileal Peyer's patches.
  • 2013
  • Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 8:12
  • Tidskriftsartikel (refereegranskat)abstract
    • Peyer's patches (PPs) are collections of lymphoid follicles in the small intestine, responsible for scanning the intestinal content for foreign antigens such as soluble molecules, particulate matter as well as intact bacteria and viruses. The immune cells of the patch are separated from the intestinal lumen by a single layer of epithelial cells, the follicle-associated epithelium (FAE). This epithelium covers the dome of the follicle and contains enterocyte-like cells and M cells, which are particularly specialized in taking up antigens from the gut. However, the presence and number of goblet cells as well as the presence of mucus on top of the FAE is controversial. When mouse ileal PPs were mounted in a horizontal Ussing-type chamber, we could observe a continuous mucus layer at mounting and new, easily removable mucus was released from the villi on the patch upon stimulation. Confocal imaging using fluorescent beads revealed a penetrable mucus layer covering the domes. Furthermore, immunostaining of FAE from mice, rats and humans with a specific antibody against the main component of intestinal mucus, the MUC2 mucin, clearly identify mucin-containing goblet cells. Transmission electron micrographs further support the identification of mucus releasing goblet cells on the domes of PPs in these species.
  •  
23.
  • Faisal, Mohammed, et al. (författare)
  • Effects of analgesic and surgical modality on immune response in colorectal cancer surgery
  • 2021
  • Ingår i: Surgial oncology. - : ELSEVIER SCI LTD. - 0960-7404 .- 1879-3320. ; 38
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and objective: Different surgical methods, anesthesia, and analgesia are known to modify the surgical stress response, especially in patients with malignancy. We compared the impact of patient-controlled intravenous (PCA) versus epidural analgesia (EDA) on tumor-related mucosal immune response in patients undergoing open or laparoscopic surgery for colorectal cancer. Methods: In a University Hospital subgroup (n = 43) of a larger cohort (n = 235) of patients undergoing open or laparoscopic surgery for colorectal carcinoma randomized to PCA or EDA, colorectal tissues were stained for interleukin-10 (IL-10), tumor necrosis factor (TNF), and mast cell tryptase and then examined by immunofluorescence microscopy. Results: More IL-10+-cells were found in patients undergoing open compared to laparoscopic surgery in the PCA (P < 0.05) and EDA group (P < 0.0005), respectively, and numbers of TNF+-cells were higher in the open surgery group who received PCA (P < 0.05). No differences in IL-10 or TNF expressions were detected between EDA/PCA within the open or laparoscopic surgery groups, respectively. Fewer mast cells were observed in patients undergoing laparoscopic compared to open surgery combined with PCA (P < 0.05). Within the open surgery group, EDA resulted in fewer mucosal mast cells compared to the PCA group (P < 0.05). Conclusions: The surgical method, rather than type of analgesia, may have higher impact on peri-operative inflammation. Laparoscopic surgery when combined with EDA for colorectal cancer caused a decrease in the TNF and IL-10 expression and mast cells. EDA seems to have an anti-inflammatory effect on cancer-related inflammation during open surgery.
  •  
24.
  • Ganda Mall, John-Peter, 1988-, et al. (författare)
  • A β-Glucan-Based Dietary Fiber Reduces Mast Cell-Induced Hyperpermeability in Ileum From Patients With Crohn's Disease and Control Subjects
  • 2017
  • Ingår i: Inflammatory Bowel Diseases. - : Lippincott-Raven Publishers. - 1078-0998 .- 1536-4844. ; 24:1, s. 166-178
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Administration of β-glucan has shown immune-enhancing effects. Our aim was to investigate whether β-glucan could attenuate mast cell (MC)-induced hyperpermeability in follicle-associated epithelium (FAE) and villus epithelium (VE) of patients with Crohn's disease (CD) and in noninflammatory bowel disease (IBD)-controls. Further, we studied mechanisms of β-glucan uptake and effects on MCs in vitro.Methods: Segments of FAE and VE from 8 CD patients and 9 controls were mounted in Ussing chambers. Effects of the MC-degranulator compound 48/80 (C48/80) and yeast-derived β-1,3/1,6 glucan on hyperpermeability were investigated. Translocation of β-glucan and colocalization with immune cells were studied by immunofluorescence. Caco-2-cl1- and FAE-cultures were used to investigate β-glucan-uptake using endocytosis inhibitors and HMC-1.1 to study effects on MCs.Results: β-glucan significantly attenuated MC-induced paracellular hyperpermeability in CD and controls. Transcellular hyperpermeability was only significantly attenuated in VE. Baseline paracellular permeability was higher in FAE than VE in both groups, P<0.05, and exhibited a more pronounced effect by C48/80 and β-glucan P<0.05. No difference was observed between CD and controls. In vitro studies showed increased passage, P<0.05, of β-glucan through FAE-culture compared to Caco-2-cl1. Passage was mildly attenuated by the inhibitor methyl-β-cyclodextrin. HMC-1.1 experiments showed a trend to decreasing MC-degranulation and levels of TNF-α but not IL-6 by β-glucan. Immunofluorescence revealed more β-glucan-uptake and higher percentage of macrophages and dendritic cells close to β-glucan in VE of CD compared to controls.Conclusions: We demonstrated beneficial effects of β-glucan on intestinal barrier function and increased β-glucan-passage through FAE model. Our results provide important and novel knowledge on possible applications of β-glucan in health disorders and diseases characterized by intestinal barrier dysfunction.
  •  
25.
  • Ganda Mall, John-Peter, 1988-, et al. (författare)
  • Are self-reported gastrointestinal symptoms among older adults associated with increased intestinal permeability and psychological distress?
  • 2018
  • Ingår i: BMC Geriatrics. - : BioMed Central. - 1471-2318. ; 18:1
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Despite the substantial number of older adults suffering from gastrointestinal (GI) symptoms little is known regarding the character of these complaints and whether they are associated with an altered intestinal barrier function and psychological distress. Our aim was to explore the relationship between self-reported gut health, intestinal permeability and psychological distress among older adults.METHODS: Three study populations were included: 1) older adults with GI symptoms (n = 24), 2) a group of older adults representing the general elderly population in Sweden (n = 22) and 3) senior orienteering athletes as a potential model of healthy ageing (n = 27). Questionnaire data on gut-health, psychological distress and level of physical activity were collected. Intestinal permeability was measured by quantifying zonulin in plasma. The level of systemic and local inflammation was monitored by measuring C-reactive protein (CRP), hydrogen peroxide in plasma and calprotectin in stool samples. The relationship between biomarkers and questionnaire data in the different study populations was illustrated using a Principal Component Analysis (PCA).RESULTS: Older adults with GI symptoms displayed significantly higher levels of both zonulin and psychological distress than both general older adults and senior orienteering athletes. The PCA analysis revealed a separation between senior orienteering athletes and older adults with GI symptoms and showed an association between GI symptoms, psychological distress and zonulin.CONCLUSIONS: Older adults with GI symptoms express increased plasma levels of zonulin, which might reflect an augmented intestinal permeability. In addition, this group suffer from higher psychological distress compared to general older adults and senior orienteering athletes. This relationship was further confirmed by a PCA plot, which illustrated an association between GI symptoms, psychological distress and intestinal permeability.
  •  
26.
  •  
27.
  • Ganda Mall, John Peter, 1988-, et al. (författare)
  • Differential effects of dietary fibres on colonic barrier function in elderly individuals with gastrointestinal symptoms
  • 2018
  • Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 8:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Gastrointestinal problems are common in elderly and often associated with psychological distress and increased levels of corticotrophin-releasing hormone, a hormone known to cause mast cell (MC) degranulation and perturbed intestinal barrier function. We investigated if dietary fibres (non-digestible polysaccharides [NPS]) could attenuate MC-induced colonic hyperpermeability in elderly with gastrointestinal (GI) symptoms. Colonic biopsies from elderly with diarrhoea and/or constipation (n = 18) and healthy controls (n = 19) were mounted in Ussing chambers and pre-stimulated with a yeast-derived beta (β)-glucan (0.5 mg/ml) or wheat-derived arabinoxylan (0.1 mg/ml) before the addition of the MC-degranulator Compound (C) 48/80 (10 ng/ml). Permeability markers were compared pre and post exposure to C48/80 in both groups and revealed higher baseline permeability in elderly with GI symptoms. β-glucan significantly attenuated C48/80-induced hyperpermeability in elderly with GI symptoms but not in healthy controls. Arabinoxylan reduced MC-induced paracellular and transcellular hyperpermeability across the colonic mucosa of healthy controls, but did only attenuate transcellular permeability in elderly with GI symptoms. Our novel findings indicate that NPS affect the intestinal barrier differently depending on the presence of GI symptoms and could be important in the treatment of moderate constipation and/or diarrhoea in elderly.
  •  
28.
  • Ganda Mall, John Peter, 1988-, et al. (författare)
  • Effects of Dietary Fibres on Acute Indomethacin-Induced Intestinal Hyperpermeability in the Elderly : A Randomised Placebo Controlled Parallel Clinical Trial
  • 2020
  • Ingår i: Nutrients. - : MDPI. - 2072-6643. ; 12:7
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of dietary fibres on intestinal barrier function has not been well studied, especially in the elderly. We aimed to investigate the potential of the dietary fibres oat beta-glucan and wheat arabinoxylan to strengthen the intestinal barrier function and counteract acute non-steroid anti-inflammatory drug (indomethacin)-induced hyperpermeability in the elderly. A general population of elderly subjects (>= 65 years,n= 49) was randomised to a daily supplementation (12g/day) of oat beta-glucan, arabinoxylan or placebo (maltodextrin) for six weeks. The primary outcome was change in acute indomethacin-induced intestinal permeability from baseline, assessed by an in vivo multi-sugar permeability test. Secondary outcomes were changes from baseline in: gut microbiota composition, systemic inflammatory status and self-reported health. Despite a majority of the study population (85%) showing a habitual fibre intake below the recommendation, no significant effects on acute indomethacin-induced intestinal hyperpermeability in vivo or gut microbiota composition were observed after six weeks intervention with either dietary fibre, compared to placebo.
  •  
29.
  •  
30.
  • Ganda Mall, John-Peter, 1988- (författare)
  • Non-digestible Polysaccharides and Intestinal Barrier Function : specific focus on its efficacy in elderly and patients with Crohn’s disease
  • 2018
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • A large number of elderly suffer from gastrointestinal (GI) symptoms such as constipation and diarrhoea. The underlying mechanisms of age-acquired GI symptoms are not well studied but are necessary to clarify in order to recommend the right treatment. Non-digestible polysaccharides (NPS) are dietary fibres that could have beneficial effects on the intestinal immune system and barrier function, although their efficacy needs to be evaluated. Paper I showed that elderly with GI symptoms have significantly higher small intestinal permeability than a general elderly population, along with a stronger association to psychological distress. In Paper II we performed a randomised controlled trial with a general population of elderly that consumed either placebo, the NPS’s arabinoxylan or oat β-glucan for a period of 6 weeks. No protective effects were observed related to indomethacin-induced intestinal hyperpermeability, inflammatory markers, or self-reported health if compared to placebo. Paper III showed that stimulation with a yeast-derived β-glucan significantly attenuated Compound (C) 48/80-induced hyperpermeability in colonic biopsies from elderly with GI symptoms mounted in Ussing chambers, but not in young healthy adults. Arabinoxylan attenuated only C48/80-induced transcellular permeability in elderly but both paracellular and transcellular permeability in young healthy adults. Paper IV showed that the same yeast-derived β-glucan from paper III could cross the epithelium of ileal tissues from patients with Crohn’s disease (CD) and non-CD controls, mounted in Ussing chambers, and attenuate C48/80-induced hyperpermeability. In conclusion, we found that elderly with GI symptoms display a deteriorated barrier function and that administration of selective NPS can have beneficial effect on intestinal permeability in selective populations.
  •  
31.
  • Gerdin, Linda, et al. (författare)
  • Acute psychological stress increases paracellular permeability and modulates immune activity in rectal mucosa of healthy volunteers
  • 2023
  • Ingår i: United European Gastroenterology journal. - : John Wiley & Sons Ltd. - 2050-6406 .- 2050-6414. ; 11:1, s. 31-41
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Psychological stress and increased permeability are implicated as contributing factors in the initiation and worsening of gastrointestinal diseases. A link between stress and intestinal permeability has been shown in animal models as well as in human small intestine, but stress effects on the human colorectal mucosal barrier has not been reported. Objective To investigate the potential effects of acute psychological stress on colorectal mucosal barrier function and to explore stress-induced molecular events in the rectal mucosa under healthy conditions. Methods Endoscopic biopsies were taken from the rectosigmoid region of healthy volunteers, who had been subjected to dichotomous listening stress and after a control session, respectively. Paracellular and transcellular permeability were assessed in modified Ussing chambers. RNA expression (microarray technology confirmed by quantitative real-time polymerase chain reaction) and biological pathway analysis were used to investigate the local mucosal response to acute stress. Results Dichotomous listening stress induced a subjective and objective stress response, and significantly increased paracellular but not transcellular permeability. We also identified a stress-induced reduction in RNA expression of genes related to immune cell activation and maturation (CR2, CD20, TCLA1, BANK1, CD22, FDCSP), signaling molecules of homing of immune cells to the gut (chemokines: CCL21, CXCL13, and CCL19, and receptors: CCR7, CXCR5), and innate immunity (DUOX2). Eight of the 10 top down-regulated genes are directly involved in B cell activation, signaling and migration. The systemic stress response correlated positively with paracellular permeability and negatively with DUOX2 expression. Conclusion Dichotomous listening stress increases paracellular permeability and modulates immune cell activity in the rectal mucosa. Further studies are warranted to identify the primary mechanisms of stress-mediated reduction of mucosal defensive activity and barrier dysfunction, and their potential implications for gastrointestinal disorders.
  •  
32.
  • Gullberg, Elisabet, et al. (författare)
  • Identification of Cell Adhesion Molecules in the Human Follicle-Associated Epithelium That Improve Nanoparticle Uptake into the Peyer's Patches
  • 2006
  • Ingår i: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 319:2, s. 632-639
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to identify cell adhesion molecules that could serve as targets of the human follicle-associated epithelium (FAE) overlying Peyer's patches and to assess nanoparticle uptake levels across this epithelium. We first studied the expression of the mouse M-cell marker beta(1)-integrin and used a model of human FAE derived from intestinal epithelial Caco-2 cells and Raji B-cells to identify additional potential targets by cDNA array. The protein expression of potential targets in the model FAE and in human ileal FAE tissues was quantified by immunofluorescence. Integrin targeting was studied by investigating the transport of Arg-Gly-Asp (RGD)-coated (integrin- binding), Arg-Gly-Glu (RGE)-coated (nonintegrin-binding), and uncoated nanoparticles across ileal specimens mounted in Ussing chambers. Both beta(1)-integrin and the cell adhesion molecule CD9 were more abundantly expressed in the model and human FAE compared with the Caco-2 control cells or villus epithelium (VE). Uncoated nanoparticles were not taken up across either FAE or VE. General integrin targeting with RGD improved the nanoparticle transport dramatically across the FAE and to a lower extent across the VE. Compared with RGE, RGD improved transport 4-fold across the FAE. There was no difference in the transport of RGD- and RGE-coated nanoparticles across the VE. In conclusion, beta(1)-integrin and CD9 were identified as targets in human FAE. The difference in RGD- and RGE-mediated transport across the FAE, but not the VE, suggests that a specific integrin interaction was the dominating mechanism for improved nanoparticle uptake across the FAE., whereas charge interaction contributed substantially to the improved VE uptake.
  •  
33.
  •  
34.
  • Hagbom, Marie, et al. (författare)
  • Neurotrophic Factors Protect the Intestinal Barrier from Rotavirus Insult in Mice
  • 2020
  • Ingår i: mBio. - : AMER SOC MICROBIOLOGY. - 2161-2129 .- 2150-7511. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Increased intestinal permeability has been proposed as a mechanism of rotavirus-induced diarrhea. Studies with humans and mice have, however, shown that rotavirus leaves intestinal permeability unaffected or even reduced during diarrhea, in contrast to most bacterial infections. Gastrointestinal permeability is regulated by the vagus nerve and the enteric nervous system, which is composed of neurons and enteric glial cells (EGCs). We investigated whether the vagus nerve, serotonin (5-HT), EGCs, and neurotropic factors contribute to maintaining gut barrier homeostasis during rotavirus infection. Using subdiaphragmatic vagotomized and 5-HT3 receptor knockout mice, we found that the unaffected epithelial barrier during rotavirus infection is independent of the vagus nerve but dependent on 5-HT signaling through enteric intrinsic 5-HT3 receptors. Immunofluorescence analysis showed that rotavirus-infected enterocytes were in close contact with EGCs and enteric neurons and that the glial cell-derived neurotrophic factor (GDNF) was strongly upregulated in enterocytes of infected mice. Moreover, rotavirus and 5-HT activated EGCs (P < 0.001). Using Ussing chambers, we found that GDNF and S-nitrosoglutathione (GSNO) led to denser epithelial barriers in small intestinal resections from noninfected mice (P < 0.01) and humans (P < 0.001) and that permeability was unaffected in rotavirus-infected mice. GSNO made the epithelial barrier denser in Caco-2 cells by increasing the expression of the tight junction protein zona occludens 1 (P < 0.001), resulting in reduced passage of fluorescein isothiocyanate dextran (P < 0.05) in rotavirus-infected monolayers. This is the first report to show that neurotropic factors contribute to maintaining the gut epithelial barrier during viral insult. IMPORTANCE Human and mouse studies have shown that rotavirus infection is associated with low inflammation and unaffected intestinal barrier at the time of diarrhea, properties different from most bacterial and inflammatory diseases of the gut. We showed by in vitro, ex vivo, and in vivo experiments that neurotrophic factors and 5-HT have barrier protective properties during rotavirus insult. These observations advance our understanding of how the gut barrier is protected against rotavirus and suggest that rotavirus affects the gut barrier differently from bacteria. This is the first report to show that neurotrophic factors contribute to maintain the gut epithelial barrier during viral insult.
  •  
35.
  • Hamed, Samira A., et al. (författare)
  • Butyrate reduces adherent-invasive E. coli-evoked disruption of epithelial mitochondrial morphology and barrier function: involvement of free fatty acid receptor 3
  • 2023
  • Ingår i: Gut microbes. - : TAYLOR & FRANCIS INC. - 1949-0976 .- 1949-0984. ; 15:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Gut bacteria provide benefits to the host and have been implicated in inflammatory bowel disease (IBD), where adherent-invasive E. coli (AIEC) pathobionts (e.g., strain LF82) are associated with Crohn's disease. E. coli-LF82 causes fragmentation of the epithelial mitochondrial network, leading to increased epithelial permeability. We hypothesized that butyrate would limit the epithelial mitochondrial disruption caused by E. coli-LF82. Human colonic organoids and the T84 epithelial cell line infected with E. coli-LF82 (MOI = 100, 4 h) showed a significant increase in mitochondrial network fission that was reduced by butyrate (10 mM) co-treatment. Butyrate reduced the loss of mitochondrial membrane potential caused by E. coli-LF82 and increased expression of PGC-1$\alpha $alpha mRNA, the master regulator of mitochondrial biogenesis. Metabolomics revealed that butyrate significantly altered E. coli-LF82 central carbon metabolism leading to diminished glucose uptake and increased succinate secretion. Correlating with preservation of mitochondrial network form/function, butyrate reduced E. coli-LF82 transcytosis across T84-cell monolayers. The use of the G-protein inhibitor, pertussis toxin, implicated GPCR signaling as critical to the effect of butyrate, and the free fatty acid receptor three (FFAR3, GPR41) agonist, AR420626, reproduced butyrate's effect in terms of ameliorating the loss of barrier function and reducing the mitochondrial fragmentation observed in E. coli-LF82 infected T84-cells and organoids. These data indicate that butyrate helps maintain epithelial mitochondrial form/function when challenged by E. coli-LF82 and that this occurs, at least in part, via FFAR3. Thus, loss of butyrate-producing bacteria in IBD in the context of pathobionts would contribute to loss of epithelial mitochondrial and barrier functions that could evoke disease and/or exaggerate a low-grade inflammation.
  •  
36.
  • Katinios, Georgios, et al. (författare)
  • Increased Colonic Epithelial Permeability and Mucosal Eosinophilia in Ulcerative Colitis in Remission Compared With Irritable Bowel Syndrome and Health
  • 2020
  • Ingår i: Inflammatory Bowel Diseases. - : Oxford University Press. - 1078-0998 .- 1536-4844. ; 26:7, s. 974-984
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundBarrier dysfunction is recognized as a pathogenic factor in ulcerative colitis (UC) and irritable bowel syndrome (IBS), but it is unclear to what extent the factors related to barrier dysfunction are disease-specific. The aim of this study was to compare these aspects in UC patients in remission, IBS patients, and healthy controls (HCs).MethodsColonic biopsies were collected from 13 patients with UC in remission, 15 patients with IBS-mixed, and 15 HCs. Ulcerative colitis patients had recently been treated for relapse, and biopsies were taken from earlier inflamed areas. Biopsies were mounted in Ussing chambers for measurements of intestinal paracellular permeability to 51chromium (Cr)-ethylenediaminetetraacetic acid (EDTA). In addition, biopsies were analyzed for mast cells and eosinophils by histological procedures, and plasma tumor necrosis factor (TNF)-α was assessed by ELISA.ResultsUssing chamber experiments revealed an increased 51Cr-EDTA permeability in UC and IBS (P < 0.05). The 51Cr-EDTA permeability was higher in UC compared with IBS (P < 0.005). There were increased numbers of mucosal mast cells and eosinophils in UC and IBS and more eosinophils in UC compared with IBS (P < 0.05). Also, increased extracellular granule content was found in UC compared with HCs (P < 0.05). The 51Cr-EDTA permeability correlated significantly with eosinophils in all groups. Plasma TNF-α concentration was higher in UC compared with IBS and HCs (P < 0.0005).ConclusionsResults indicate a more permeable intestinal epithelium in inactive UC and IBS compared with HCs. Ulcerative colitis patients, even during remission, demonstrate a leakier barrier compared with IBS. Both eosinophil numbers and activation state might be involved in the increased barrier function seen in UC patients in remission.
  •  
37.
  • Keita, Åsa, 1973- (författare)
  • Barrier function of the Follicle-Associated Epithelium in Stress and Crohn's disease
  • 2007
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Crohns sjukdom är en kronisk inflammatorisk tarmsjukdom av okänd orsak. Det tidigaste tecknet på Crohns sjukdom är mikroskopiska sår i det s.k. follikelassocierade epitelet (FAE) som täcker ansamlingar av immunceller i tarmen. FAE är specialiserat för att fånga innehåll från tarmen och transportera det till underliggande immunvävnad. Denna funktion är viktig för att inducera skyddande immunsvar, men den utgör också en ingångsväg för sjukdomsalstrande bakterier. Crohns sjukdom är associerat med ett kraftigt ökat immunsvar mot bakterier, och sjukdomsförloppet kan ändras av stress.Det övergripande syftet med avhandlingen var att studera effekterna av stress på FAE samt att undersöka rollen av FAE vid utvecklingen av tarminflammation, särskilt vid Crohns sjukdom.Inledningsvis studerades effekterna av psykologisk stress på FAE. Stressade råttor uppvisade ökad genomsläpplighet av bakterier efter stress, och passagen var högre i FAE än i vanligt epitel. Efterföljande experiment visade att stressförändringarna i slemhinnan regleras via kortikotropinfrisättande hormon och mastceller. Vidare visade det sig att vasoaktiv intestinal peptid kunde efterlikna stressens effekter på genomsläppligheten, och att detta kunde förhindras genom att blockera mastcellerna.Studier av tunntarmsslemhinna från patienter med icke-inflammatorisk tarmsjukdom och friska kontroller visade en högre passage av bakterier i FAE än i vanligt epitel. Hos patienter med Crohns sjukdom var bakteriepassagen genom FAE betydligt ökad jämfört med kontroller.Resultaten från detta avhandlingsarbete visar att stress kan förändra upptaget av bakterier från tarmen via FAE, med mekanismer som innefattar kortikotropinfrisättande hormon och mastceller. Detta har gett nya kunskaper kring regleringen av slemhinnebarriären. Vidare presenterar denna avhandling nya insikter i sjukdomsuppkomsten vid Crohns sjukdom genom att påvisa en tidigare okänd defekt i barriärfunktionen i FAE.
  •  
38.
  • Keita, Åsa, et al. (författare)
  • Enhanced E. coli LF82 Translocation through the Follicle-associated Epithelium in Crohns Disease is Dependent on Long Polar Fimbriae and CEACAM6 expression, and Increases Paracellular Permeability
  • 2020
  • Ingår i: Journal of Crohn's & Colitis. - : OXFORD UNIV PRESS. - 1873-9946 .- 1876-4479. ; 14:2, s. 216-229
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and Aims: Patients with Crohns disease [CD] harbour an increased number of adherent-invasive E. coli [AIEC]. The strain LF82, identified in the ileal mucosa of CD patients, has been extensively studied for pathogenic mechanisms. However, understanding of the interaction of LF82 with the intestinal mucosa of CD patients is lacking. Methods: Here, we investigated the importance of long polar fimbriae [LPF] type 1 pili and the carcinoembryonic antigen-related cell-adhesion molecule 6 [CEACAM6] for translocation of LF82 in an in vitro model of follicle-associated epithelium [FAE], and in the FAE and villus epithelium [VE] of patients with CD and controls, using Ussing chambers. Results: Significantly greater LF82 passage occurred in the FAE model compared with in the VE Caco-2cl1 mono-culture. Moreover, bacterial translocation was inhibited by either LPF disruption or pre-incubation with anti-CEACAM6 antibody. Tissue mounted in Ussing chambers showed significantly higher LF82 passage in FAE from patients with CD compared with control FAE, that was diminished in LF82 lacking LPF and by blocking host CEACAM6. Interestingly, addition of LF82 to the CD FAE tissues significantly increased paracellular permeability [of (51)Chromium-EDTA] compared with baseline, and the increase was inhibited by anti-CEACAM6. Immunofluorescence and immunoblots showed higher expression of CEACAM6 in FAE of patients with CD compared with in FAE from controls. Conclusions: These data suggest that the FAE of CD patients is a site of vulnerability for invasion by LF82 via a mechanism that requires both bacterial LPF and host CEACAM6. Further, LF82 has the ability to increase paracellular passage through the FAE of patients with CD. These data can help define novel therapeutic targets in CD for the prevention of clinical recurrence.
  •  
39.
  • Keita, Åsa, et al. (författare)
  • Gut barrier dysfunction : a primary defect in twins with Crohn's disease predominantly caused by genetic predisposition
  • 2018
  • Ingår i: Journal of Crohn's & Colitis. - : Elsevier. - 1873-9946 .- 1876-4479. ; 12:10, s. 1200-1209
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and aims: The aetiology of Crohn's disease is poorly understood. By investigating twin pairs discordant for Crohn's disease we aimed to assess if the dysregulated barrier represents a cause or a consequence of inflammation and to evaluate the impact of genetic predisposition on barrier function.Methods: Ileal biopsies from 15 twin pairs discordant for Crohn's disease (monozygotic n=9, dizygotic n=6) and 10 external controls were mounted in Ussing chambers to assess paracellular permeability to51Chromium (Cr)-EDTA and trancellular passage to non-pathogenic E. coli K-12. Experiments were performed with and without provocation with acetylsalicylic acid. Immunofluorescence and ELISA were used to quantify the expression level of tight junction proteins.Results: Healthy co-twins and affected twins displayed increased 51Cr-EDTA permeability at 120 min both with Acetylsalicylic acid (p<0.001) and without (p<0.001) when compared to controls. A significant increase in 51Cr-EDTA flux was seen already at 20 minutes in healthy monozygotic co-twins compared to controls (p≤0.05) when stratified by zygosity, but not in healthy dizygotic co-twins. No difference in E. coli passage was observed between groups. Immunofluorescence of the tight junction proteins claudin-5 and tricellulin showed lower levels in healthy co-twins (p<0.05) and affected twins (p<0.05) compared to external controls, while ELISA only showed lower tricellulin in Crohn's disease twins (p<0.05).Conclusion: Our results suggest that barrier dysfunction is a primary defect in Crohn's disease, since changes were predominantly seen in healthy monozygotic co-twins. Passage of E. coli seems to be a consequence of inflammation rather than representing a primary defect.
  •  
40.
  • Keita, Åsa, 1973-, et al. (författare)
  • Increased uptake of non-pathogenic E. coli via the follicle-associated epithelium in longstanding ileal Crohn's disease
  • 2008
  • Ingår i: Journal of Pathology. - : Wiley. - 0022-3417 .- 1096-9896. ; 215:2, s. 135-144
  • Tidskriftsartikel (refereegranskat)abstract
    • In Crohn's disease (CD), inflammation is driven by luminal commensal micro-organisms, however, mechanisms of early phases of inflammation need further clarification. The earliest observable lesions of recurrent CD are microscopic erosions at the specialized follicle-associated epithelium (FAE), which lines the Peyer's patches. Therefore, our aim was to investigate the mucosal barrier to non-pathogenic bacteria in FAE of CD. The FAE of macroscopically normal ileum from patients with longstanding CD, ulcerative colitis, and controls was studied in Ussing chambers regarding electrophysiology and permeability to 51Cr-EDTA, horseradish peroxidase, and non-pathogenic E. coli strains. Transepithelial passage routes and uptake into dendritic cells were studied by confocal and electron microscopy. FAE of CD showed increased numbers of adherent bacteria, after E. coli exposure in Ussing chambers, as well as spontaneously in non-exposed archival surgical tissues. Further, we found increased uptake of fluorescent E. coli K-12 and HB101 across FAE of CD, but not in ulcerative colitis. Microscopy demonstrated intercellular and transcellular uptake of E. coli in CD, but only transcellular in controls. FAE exposed to E. coli demonstrated changes in conductance and 51Cr-EDTA permeability, suggesting that bacteria affected the paracellular pathway in CD mucosa. Following bacterial uptake, CD mucosa also demonstrated an increased percentage of E. coli co-localizing with dendritic cells, and augmented tissue release of TNF-α. Our data present novel insights into the pathophysiology of CD by demonstrating a previously unrecognized defect of FAE barrier to bacteria in ileal CD, leading to increased load of commensal bacteria to the inductive sites of mucosal immunity. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
  •  
41.
  • Keita, Åsa, et al. (författare)
  • Mucosal permeability and mast cells as targets for functional gastrointestinal disorders
  • 2018
  • Ingår i: Current opinion in pharmacology (Print). - : ELSEVIER SCI LTD. - 1471-4892 .- 1471-4973. ; 43, s. 66-71
  • Forskningsöversikt (refereegranskat)abstract
    • The intestinal mucosa is constantly exposed to harmful lumina! content, and uptake is closely controlled and regulated by neuro-immune factors. If control is broken, it might lead to ongoing enhanced mucosal permeability, potentially resulting in functional gastrointestinal disorders. The importance of mast cells in the regulation of the mucosal barrier has become obvious, and increased numbers and more activated mast cells have been observed in irritable bowel syndrome, functional dyspepsia and gastroesophageal reflux disease. To target the disturbed mucosal permeability, directly or via mast cells, is therefore currently of major interest. For example, administration of mast cell stabilizers and probiotics have shown promising effects in patients with functional gastrointestinal disorders.
  •  
42.
  • Keita, Åsa V., et al. (författare)
  • Barrier dysfunction and bacterial uptake in the follicle-associated epithelium of ileal Crohns disease
  • 2012
  • Ingår i: Annals of the New York Academy of Sciences. - : Wiley. - 0077-8923 .- 1749-6632. ; 1258:1, s. 125-134
  • Tidskriftsartikel (refereegranskat)abstract
    • The ability to control uptake across the mucosa and protect from harmful substances in the gut lumen is defined as intestinal barrier function. The etiology of Crohns disease is unknown, but genetic, environmental, and immunological factors all contribute. The frontline between these factors lies in the intestinal barrier. The most important inflammation-driving environmental factor in Crohns disease is the microbiota, where Esherichia coli strains have been assigned a key role. The first observable signs of Crohns disease are small aphtoid ulcers over Peyers patches and lymphoid follicles. The overlaying follicle-associated epithelium (FAE) is specialized for luminal sampling and is an entry site for antigens and bacteria. We have demonstrated increased E. coli uptake across the FAE in Crohns disease, which may initiate inflammation. This short review will discuss barrier dysfunction and bacteria in the context of ileal Crohns disease, and how the FAE might be the site of initial inflammation.
  •  
43.
  • Keita, Åsa V, et al. (författare)
  • Characterization of antigen and bacterial transport in the follicle-associated epithelium of human ileum
  • 2006
  • Ingår i: Laboratory investigation. - : Elsevier BV. - 0023-6837 .- 1530-0307. ; 86:5, s. 504-516
  • Tidskriftsartikel (refereegranskat)abstract
    • The follicle-associated epithelium (FAE), covering Peyer's patches, provides a route of entry for antigens and microorganisms. Animal studies showed enhanced antigen and bacterial uptake in FAE, but no study on barrier function of human FAE has been reported. Our aim was to characterize the normal barrier properties of human FAE. Specimens of normal ileum were taken from 30 patients with noninflammatory colonic disease. Villus epithelium (VE) and FAE were identified and mounted in Ussing chambers. Permeability to 51Cr-EDTA, transmucosal flux of the protein antigen, horseradish peroxidase (HRP), and transport of fluorescent Escherichia coli (chemically killed K-12 and live HB101) were measured. Uptake mechanisms were studied by confocal- and transmission electron microscopy, and by using pharmacological inhibitors in an in vitro coculture model of FAE and in human ileal FAE. HRP flux was substantially higher in FAE than in VE, and was reduced by an amiloride analog. Electron microscopy showed HRP-containing endosomes. Transport of E. coli K-12 and HB101 was also augmented in FAE and was confirmed by confocal microscopy. In vitro coculture experiments and electron microscopy revealed actin-dependent, mainly transcellular, uptake of E. coli K-12 into FAE. 51Cr-EDTA permeability was equal in FAE and VE. Augmented HRP flux and bacterial uptake but similar paracellular permeability, suggest functional variations of transcellular transport in the FAE. We show for the first time that FAE of human ileum is functionally distinct from regular VE, rendering the FAE more prone to bacterial–epithelial cell interactions and delivery of antigens to the mucosal immune system.
  •  
44.
  •  
45.
  •  
46.
  • Keita, Åsa V, et al. (författare)
  • Stress-induced barrier disruption of the follicle-associated epithelium involves corticotropin-releasing hormone, vasoactive intestinal peptide and mast cells
  • 2010
  • Ingår i: Neurogastroenterology and Motility. - : Wiley. - 1350-1925 .- 1365-2982. ; 22:7, s. 770-e222
  • Tidskriftsartikel (refereegranskat)abstract
    • Background The follicle-associated epithelium (FAE) is specialized in uptake and sampling of luminal antigens and bacteria. We previously showed that stress increased FAE permeability in rats. An increased uptake may alter antigen exposure in Peyers patches leading to intestinal disease. The aim of this study was to elucidate mechanisms involved in the acute stress-induced increase in FAE permeability. Methods Rats were pretreated i.p. with corticotropin-releasing hormone receptor (CRH-R) antagonist, neurokinin receptor 1 (NK-1R) antagonist, atropine, the mast cell stabilizer doxantrazole (DOX), or NaCl, and submitted to 1-h acute water avoidance stress. FAE tissues were mounted in Ussing chambers for measurements of permeability to 51Cr-EDTA, horseradish peroxidase (HRP) and chemically killed Escherichia coli K-12. Further, FAE segments were exposed in vitro in chambers to CRH, substance P (SP), carbachol, and DOX. Neurotransmitter- and receptor distribution was studied by immunohistochemistry. Key Results Stress-induced increases in uptake across FAE of HRP and E. coli were reduced by DOX, CRH-R antagonist and atropine, whereas the NK-1R antagonist decreased 51Cr-EDTA permeability. Exposure to CRH and carbachol increased HRP and E. coli passage, whereas SP increased bacterial and 51Cr-EDTA permeability. DOX counteracted all of these effects. Immunohistochemistry revealed CRH, acetylcholine, SP, and their receptors on mast cells within the Peyers patches, subepithelial dome, and adjacent villi. Conclusions & Inferences Corticotropin-releasing hormone and acetylcholine signaling affect mainly transcellular permeability while SP seems more selective toward the paracellular pathways. Our findings may be of importance for the understanding of the pathogenesis of stress-related intestinal disorders.
  •  
47.
  • Keita, Åsa V., et al. (författare)
  • The intestinal barrier and its regulation by neuroimmune factors
  • 2010
  • Ingår i: Neurogastroenterology and Motility. - : Blackwell Publishing Ltd. - 1350-1925 .- 1365-2982. ; 22:7, s. 718-733
  • Forskningsöversikt (refereegranskat)abstract
    • Background The ability to control uptake across the mucosa and protect from damage of harmful substances from the lumen is defined as intestinal barrier function. A disturbed barrier dysfunction has been described in many human diseases and animal models, for example, inflammatory bowel disease, irritable bowel syndrome, and intestinal hypersensitivity. In most diseases and models, alterations are seen both of the paracellular pathway, via the tight junctions, and of the transcellular routes, via different types of endocytosis. Recent studies of pathogenic mechanisms have demonstrated the important role of neuroimmune interaction with the epithelial cells in the regulation of barrier function. Neural impulses from extrinsic vagal and/or sympathetic efferent fibers or intrinsic enteric nerves influence mucosal barrier function via direct effects on epithelial cells or via interaction with immune cells. For example, by nerve-mediated activation by corticotropin-releasing hormone or cholinergic pathways, mucosal mast cells release a range of mediators with effects on transcellular, and/or paracellular permeability (for example, tryptase, TNF-alpha, nerve growth factor, and interleukins). Purpose In this review, we discuss current physiological and pathophysiological aspects of the intestinal barrier and, in particular, its regulation by neuroimmune factors.
  •  
48.
  • Keita, Åsa, et al. (författare)
  • Vasoactive intestinal polypeptide regulates barrier function via mast cells in human intestinal follicle-associated epithelium and during stress in rats
  • 2013
  • Ingår i: Neurogastroenterology and Motility. - : Wiley-Blackwell. - 1350-1925 .- 1365-2982. ; 25:6, s. e406-e417
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Vasoactive intestinal polypeptide (VIP) has been implicated as a regulator of intestinal barrier function and inflammation. Our aim was to elucidate the role of VIP in follicle-associated epithelium (FAE) and villus epithelium (VE) permeability following stress in rats and on human intestinal barrier function. Methods Rats were injected intraperitoneally (i.p.) with VIP receptor-antagonists (anti-VPACs), a mast cell stabilizer, doxantrazole (DOX), or NaCl, and submitted to acute water avoidance stress. Ileal segments were mounted in Ussing chambers to assess 51chromium-edta (51Cr-edta) and Escherichia (E.) coli (strain K-12) permeability. Rat ileal and human ileal and colonic segments were exposed to VIP +/- anti-VPACs or DOX. An in vitro co-culture model of human FAE was used to study epithelial-VIP effects. VIP/VPACs distribution was assessed by microscopy. Key Results Stress increased 51Cr-edta and E.coli permeability in VE and FAE. The increases were abolished by i.p. injection of DOX or anti-VPACs. Ileal VIP-exposure ex vivo increased bacterial passage and this was reduced by DOX. In human FAE ex vivo, VIP treatment doubled bacterial uptake, which was normalized by DOX or anti-VPACs. No barrier effects were observed in human colonic tissue. VPACs were found in rat and human ileal follicles, with partial mast cell co-localization. The co-culture model confirmed VIPmast cellepithelial interactions in the regulation of barrier function. Conclusions andamp; Inferences Stress affects the FAE barrier by mechanisms involving VIP and VPACs on mucosal mast cells. We suggest a regulatory role for VIP in the control of ileal permeability that may be relevant to bacterialepithelial interactions in stress-related intestinal disorders.
  •  
49.
  • Kokkinou, Efthymia, et al. (författare)
  • CD45RA(+)CD62L(-) ILCs in human tissues represent a quiescent local reservoir for the generation of differentiated ILCs
  • 2022
  • Ingår i: Science immunology. - : AMER ASSOC ADVANCEMENT SCIENCE. - 2470-9468. ; 7:70
  • Tidskriftsartikel (refereegranskat)abstract
    • Innate lymphoid cells (ILCs) are highly plastic and predominantly mucosal tissue-resident cells that contribute to both homeostasis and inflammation depending on the microenvironment. The discovery of naive-like ILCs suggests an ILC differentiation process that is akin to naive T cell differentiation. Delineating the mechanisms that underlie ILC differentiation in tissues is crucial for understanding ILC biology in health and disease. Here, we showed that tonsillar ILCs expressing CD45RA lacked proliferative activity, indicative of cellular quiescence. CD62L distinguished two subsets of CD45RA(+) ILCs. CD45RA(+)CD62L(+) ILCs (CD62L(+) ILCs) resembled circulating naive ILCs because they lacked the transcriptional, metabolic, epigenetic, and cytokine production signatures of differentiated ILCs. CD45RA(+)CD62L(-) ILCs (CD62L(-) ILCs) were epigenetically similar to CD62L(+) ILCs but showed a transcriptional, metabolic, and cytokine production signature that was more akin to differentiated ILCs. CD62L(+) and CD62L(-) ILCs contained uni- and multipotent precursors of ILC1s/NK cells and ILC3s. Differentiation of CD62L(+) and CD62L(-) ILCs led to metabolic reprogramming including up-regulation of genes associated with glycolysis, which was needed for their effector functions after differentiation. CD62L(-) ILCs with preferential differentiation capacity toward IL-22-producing ILC3s accumulated in the inflamed mucosa of patients with inflammatory bowel disease. These data suggested distinct differentiation potential of CD62L(+) and CD62L(-) ILCs between tissue microenvironments and identified that manipulation of these cells is a possible approach to restore tissue-immune homeostasis.
  •  
50.
  • Ling Lundström, Maria, et al. (författare)
  • Faecal biomarkers for diagnosis and prediction of disease course in treatment-naïve patients with IBD
  • 2024
  • Ingår i: Alimentary Pharmacology and Therapeutics. - : John Wiley & Sons. - 0269-2813 .- 1365-2036. ; 60:6, s. 765-777
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Faecal biomarkers can be used to assess inflammatory bowel disease (IBD).Aim: To explore the performance of some promising biomarkers in diagnosing and predicting disease course in IBD.Methods: We included 65 patients with treatment-na & iuml;ve, new-onset Crohn's disease (CD), 90 with ulcerative colitis (UC), 67 symptomatic controls (SC) and 41 healthy controls (HC) in this prospective observational study. We analysed faecal samples for calprotectin (FC), myeloperoxidase (MPO), human neutrophil lipocalin (HNL), eosinophil cationic protein ECP and eosinophil-derived neurotoxin (EDN) and compared markers among groups. We assessed the diagnostic capability of biomarkers with receiver operating characteristic curves. Clinical disease course was determined for each patient with IBD and analysed the association with biomarkers by logistic regression.Results: All markers were elevated at inclusion in patients with IBD compared with HC (p < 0.001) and SC (p < 0.001). FC (AUC 0.85, 95% CI: 0.79-0.89) and MPO (AUC 0.85, 95% CI: 0.80-0.89) showed the highest diagnostic accuracy in distinguishing IBD from SC. The diagnostic ability of biomarkers differed between IBD subtypes with the highest performance for FC and MPO in CD. The diagnostic accuracy was further improved by combining FC and MPO (p = 0.02). Levels of FC, MPO and HNL at inclusion were predictive of an aggressive disease course with MPO showing the strongest association (p = 0.006).Conclusions: This study provides new insight into the diagnostic and prognostic capability of neutrophil and eosinophil biomarkers in IBD and suggests that MPO, alone or in combination with FC, may add to the diagnostic power of faecal biomarkers.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-50 av 86
Typ av publikation
tidskriftsartikel (67)
doktorsavhandling (9)
annan publikation (5)
forskningsöversikt (5)
Typ av innehåll
refereegranskat (71)
övrigt vetenskapligt/konstnärligt (15)
Författare/redaktör
Keita, Åsa (52)
Söderholm, Johan D (39)
Keita, Åsa V. (12)
Schoultz, Ida, 1979- (11)
Lindqvist, Carl Mårt ... (11)
Walter, Susanna (11)
visa fler...
Keita, Åsa, 1973- (10)
Halfvarson, Jonas, 1 ... (8)
Bednarska, Olga (8)
Ericson, Ann-Charlot ... (8)
Söderholm, Johan D., ... (7)
Ganda Mall, John Pet ... (7)
Artursson, Per (6)
Mckay, Derek M. (6)
Repsilber, Dirk, 197 ... (6)
D'Amato, Mauro (6)
Tinnerfelt Winberg, ... (6)
Bergemalm, Daniel, 1 ... (5)
Brummer, Robert Jan, ... (5)
Casado-Bedmar, Maite (5)
Satsangi, Jack (5)
Wang, Arthur (5)
Myrelid, Pär (4)
Jones, Michael P (4)
Wallon, Conny (4)
Haapaniemi, Staffan (4)
Hjortswang, Henrik (4)
Kruse, Robert, 1972- (4)
Gullberg, Elisabet (4)
Biskou, Olga (4)
Vicario, Maria (4)
Olbjørn, Christine (4)
Meira de Faria, Feli ... (4)
Campbell, Barry J (4)
Gustafson-Svärd, Chr ... (4)
Engström, Maria (3)
Gomollon, Fernando (3)
Magnusson, Karl-Eric (3)
Magnusson, Maria K, ... (3)
Öhman, Lena, 1967 (3)
Heil, Stéphanie (3)
Carlson, Marie, 1957 ... (3)
Bednarska, Olga, 197 ... (3)
Kalla, Rahul (3)
Jahnsen, Jørgen (3)
Detlie, Trond Espen (3)
Ricanek, Petr (3)
Peterson, Christer (3)
Hedin, Charlotte R. ... (3)
Strid, Hans (3)
visa färre...
Lärosäte
Linköpings universitet (77)
Örebro universitet (21)
Uppsala universitet (14)
Karolinska Institutet (10)
Göteborgs universitet (5)
Linnéuniversitetet (4)
visa fler...
Umeå universitet (2)
Mälardalens universitet (1)
Lunds universitet (1)
Högskolan Dalarna (1)
Sophiahemmet Högskola (1)
visa färre...
Språk
Engelska (84)
Odefinierat språk (2)
Forskningsämne (UKÄ/SCB)
Medicin och hälsovetenskap (59)
Naturvetenskap (11)
Lantbruksvetenskap (1)

År

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy