| 1. |
- Al-Saffar, Anas Kh. 1969-
(författare)
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Gastrointestinal Permeability and Motility in Inflammatory Bowel Disease
- 2019
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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.
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| 2. |
- Alkaissi, Lina Y., et al.
(författare)
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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
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Ingår i: Inflammatory Bowel Diseases. - : OXFORD UNIV PRESS INC. - 1078-0998 .- 1536-4844. ; 27:7, s. 1116-1127
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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.
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| 3. |
- Bednarska, Olga, et al.
(författare)
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A postbiotic fermented oat gruel may have a beneficial effect on the colonic mucosal barrier in patients with irritable bowel syndrome
- 2022
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Ingår i: Frontiers in Nutrition. - : FRONTIERS MEDIA SA. - 2296-861X. ; 9
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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).
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| 4. |
- Bednarska, Olga, 1973-
(författare)
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Peripheral and Central Mechanisms in Irritable Bowel Syndrome : in search of links
- 2019
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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.
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| 5. |
- Bednarska, Olga, et al.
(författare)
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Vasoactive Intestinal Polypeptide and Mast Cells Regulate Increased Passage of Colonic Bacteria in Patients With Irritable Bowel Syndrome
- 2017
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Ingår i: Gastroenterology. - : W B SAUNDERS CO-ELSEVIER INC. - 0016-5085 .- 1528-0012. ; 153:4, s. 948-
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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.
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| 6. |
- Beeckmans, Dorien, et al.
(författare)
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Relationship between bile salts, bacterial translocation, and duodenal mucosal integrity in functional dyspepsia
- 2020
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Ingår i: Neurogastroenterology and Motility. - : WILEY. - 1350-1925 .- 1365-2982. ; 32:5
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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.
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| 7. |
- Bergemalm, Daniel, 1977-, et al.
(författare)
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Systemic Inflammation in Preclinical Ulcerative Colitis
- 2021
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Ingår i: Gastroenterology. - : AGA Institute. - 0016-5085 .- 1528-0012. ; 161:5, s. 1526-1539.e9
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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.
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| 8. |
- Bhattacharya, Pradyot, et al.
(författare)
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Complement opsonization of HIV affects primary infection of human colorectal mucosa and subsequent activation of T cells
- 2020
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Ingår i: eLIFE. - Cambridge, United Kingdom : ELIFE SCIENCES PUBLICATIONS LTD. - 2050-084X. ; 9
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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.
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| 9. |
- Biskou, Olga, et al.
(författare)
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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
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Ingår i: Cells. - Basel, Switzerland : MDPI. - 2073-4409. ; 11:3
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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.
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| 10. |
- Carlander, J, et al.
(författare)
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Comparison of experimental nerve injury caused by ultrasonically activated scalpel and electrosurgery.
- 2005
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Ingår i: The British journal of surgery. - : Oxford University Press (OUP). - 0007-1323 .- 1365-2168. ; 92:6, s. 772-7
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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.
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