| 1. |
- Ellegård, Rada, 1985-
(författare)
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Effects of Complement Opsonization of HIV on Dendritic Cells : and Implications for the Immune Response
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dendritic cells are key players during HIV pathogenesis, and shape both the immediate immune response at the site of infection as well as directing the adaptive immune response against the virus. HIV has developed a plethora of immune evasion mechanisms that hijack dendritic cell functions, suppressing their ability to mount an accurate immune response and exploiting them for efficient viral transfer to target T cells.To achieve successful replication within dendritic cells without triggering danger signaling, HIV accomplishes a delicate balance where only a low level of transcription can be sustained without triggering antiviral responses that would harm the virus. Here, we describe how the presence of HSV2 coinfection, which is very common in geographic areas with a high HIV prevalence and almost triples the risk of HIV acquisition, alters dendritic cell state to support much higher levels of HIV infection. We found this effect to be mediated by the STING pathway, which is involved in the sensing of DNA in the cell cytosol. STING activation led to an upregulation of factors such as IRF3 and NFkB that can be used for HIV transcription and a degradation of factors that restrict HIV replication.In addition, we describe how HIV exploits the human complement system, a group of proteins that usually help the human body to identify dangerous pathogens while avoiding reaction towards self. HIV can coat itself, i.e. become opsonized, in complement fragments that are typically only present on the body’s own cells, allowing it to activate signaling pathways that are associated with tolerance. Dendritic cells that come into contact with complement opsonized HIV do not mount danger responses, despite the fact that HIV-derived single stranded RNA triggers the pathogen recognition receptor TLR8. The suppression of danger responses is mediated by activation of complement receptor 3, and leads to an increased infection of the dendritic cell and affects its interactions with other immune cells. There is a lack of recruitment of NK cells to the site of infection, and an inhibition of NK cell killing, which plays an important role in the destruction of HIV-infected cells in vivo. T cells primed by dendritic cells exposed to complement opsonized HIV have a lower ability to develop towards effector phenotype, and have an increased expression of the markers PD1, TIM3 and LAG3 which are associated with T cell dysfunction and exhaustion. In addition, T cells primed by these dendritic cells in the presence of NK cells upregulate markers CD38, CXCR3 and CCR4, which have been linked to an increased susceptibility to HIV infection.In summary, we add to the current knowledge on HIV immune evasion mechanisms that allow the virus to establish infection, as well as describing mechanisms that govern whether dendritic cells mount danger signaling and an immune response or not.
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| 2. |
- Gullberg, Elisabet, et al.
(författare)
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Identification of Cell Adhesion Molecules in the Human Follicle-Associated Epithelium That Improve Nanoparticle Uptake into the Peyer's Patches
- 2006
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Ingår i: Journal of Pharmacology and Experimental Therapeutics. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0022-3565 .- 1521-0103. ; 319:2, s. 632-639
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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.
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| 3. |
- Abdalla, Maie, et al.
(författare)
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Anorectal Function After Ileo-Rectal Anastomosis Is Better than Pelvic Pouch in Selected Ulcerative Colitis Patients
- 2020
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Ingår i: Digestive Diseases and Sciences. - : Springer-Verlag New York. - 0163-2116 .- 1573-2568. ; , s. 250-259
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: With a lifelong perspective, 12% of ulcerative colitis patients will need a colectomy. Further reconstruction via ileo-rectal anastomosis or pouch can be affected by patients' perspective of their quality of life after surgery.AIM: To assess the function and quality of life after restorative procedures with either ileo-rectal anastomosis or ileal pouch-anal anastomosis in relation to the inflammatory activity on endoscopy and in biopsies.METHOD: A total of 143 UC patients operated with subtotal colectomy and ileo-rectal anastomosis or pouches between 1992 and 2006 at Linköping University Hospital were invited to participate. Those who completed the validated questionnaires (Öresland score, SF-36, Short Health Scale) were offered an endoscopic evaluation including multiple biopsies. Associations between anorectal function and quality of life with type of restorative procedure and severity of endoscopic and histopathologic grading of inflammation were evaluated.RESULTS: Some 77 (53.9%) eligible patients completed questionnaires, of these 68 (88.3%) underwent endoscopic evaluation after a median follow-up of 12.5 (range 3.5-19.4) years after restorative procedure. Patients with ileo-rectal anastomosis reported better overall Öresland score: median = 3 (IQR 2-5) for ileo-rectal anastomosis (n = 38) and 10 (IQR 5-15) for pouch patients (n = 39) (p < 0.001). Anorectal function (Öresland score) and endoscopic findings (Baron-Ginsberg score) were positively correlated in pouch patients (tau: 0.28, p = 0.006).CONCLUSION: Patients operated with ileo-rectal anastomosis reported better continence compared to pouches. Minor differences were noted regarding the quality of life. Ileo-rectal anastomosis is a valid option for properly selected ulcerative colitis patients if strict postoperative endoscopic surveillance is carried out.
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| 4. |
- Abdalla, Maie
(författare)
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Cancer and reconstructive surgery in Inflammatory bowel disease
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Ulcerative colitis (UC) is a chronic inflammatory disease that affects the colon. According to the literature, some thirty percent of UC patients may require a subtotal colectomy and ileostomy due to failure of medical treatment, acute toxic colitis or dysplasia/cancer diagnosis. Some patients choose to get continence restored with either an ileorectal anastomosis (IRA) or an ileal pouch-anal anastomosis (IPAA). Worldwide most surgeons prefer an IPAA to an IRA, despite reports of pouchitis, impaired fertility and fecundity. Fear of recurring proctitis and fear of rectal cancer in the remaining rectum is contributing to the choice of an IPAA. Little is known regarding the outcomes of IRA compared with IPAA in UC patients. We aimed to investigate the anorectal function, quality of life (QoL), risk of failure and rectal cancer in patients with UC restored with IRA and IPAA respectively. Methods: Data about all Inflammatory bowel disease (IBD) patients was obtained from the Swedish National Patient Register (NPR) between 1964-2014 and in one study from the Linköping University Hospital medical records 2006-2012. Patients who developed cancer were identified from the Swedish National Cancer Register. We investigated the risk of cancer and inflammation, functional outcome and failure as well as the quality of life for IRA and IPAA patients. Investigation of risk for cancer in IRA and IPAA compared with the background population was performed using survival analytic techniques: uni-and multivariate regression, Kaplan Meier curves and standardized incidence ratio. Results: Twelve percent (7,889 /63,795) of UC patients required colectomy according to the NPR. The relative risk for rectal cancer among patients with an IRA was increased (SIR 8.7). However, the absolute risk was 1.8% after a mean follow up of 8.6 years and the cumulative risk 10- and 20-years after IRA was 1.6% and 5.6%, respectively. Risk factors for rectal cancer were primary sclerosing cholangitis in patients with an IRA (hazard ratio 6.12), and severe dysplasia or cancer of the colon prior to subtotal colectomy in patients with a diverted rectum in place (hazard ratio 3.67). Regarding IPAA, the relative risk to develop rectal cancer was (SIR 0.4) compared with the background population and the absolute risk was only 0.06% after a mean of 12.2 years of follow up. Among patients operated at the Linköping University Hospital: IRA patients reported better overall continence according to the Öresland score with in median3 (IQR 2–5) for IRA (n=38) and 10 (IQR 5–15) for IPAA (n=39, p<0.001). There were no major differences regarding the QoL. According to the NPR, after a median follow up of 12.4 years failure occurred in 265(32%) out of 1112 patients, of which 76 were secondarily reconstructed with an IPAA. Failure of the IPAA occurred in 103 (6%) patients with primary and in 6 (8%) patients after secondary IPAA (log-rank p=0.38). Conclusion: IRA is a safe restorative procedure for selected UC patients. Patients should be aware of the annual postoperative endoscopic evaluation with biopsies as well as the need to the use of local anti-inflammatory preparations. However, IRA should not be offered for UC patients with an associated primary sclerosing cholangitis diagnosis due to the increased risk to develop rectal cancer in their rectal mucosa. In such case, IPAA is probably the treatment of choice.
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| 5. |
- 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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| 6. |
- Casado Bedmar, Maria Teresa, 1990-
(författare)
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Neuro-immuno-regulation of inflammation in the colonic mucosa : Focus on mast cells and eosinophils in bowel disorders
- 2020
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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.
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| 7. |
- Kalla, R., et al.
(författare)
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Analysis of systemic epigenetic alterations in inflammatory bowel disease : defining geographical, genetic, and immune-inflammatory influences on the circulating methylome
- 2023
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Ingår i: Journal of Crohn's & Colitis. - : Oxford University Press. - 1873-9946 .- 1876-4479. ; 17:2, s. 170-184
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Epigenetic alterations may provide valuable insights into gene-environment interactions play in the pathogenesis of Inflammatory Bowel Disease (IBD).METHODS: Genome-wide methylation was measured from peripheral blood using the Illumina 450k platform in a case-control study in an inception cohort (295 controls, 154 CD, 161 UC, 28 IBD-U) with covariates of age, sex, and cell counts, deconvoluted by the Houseman method. Genotyping was performed using Illumina HumanOmniExpressExome-8 BeadChips and gene expression using Ion AmpliSeq Human Gene Expression Core Panel. Treatment escalation was characterised by the need for biological agents or surgery after initial disease remission.RESULTS: A total of 137 differentially methylated positions (DMP) were identified in IBD, including VMP1/MIR21 (p=9.11×10 -15) and RPS6KA2 (6.43×10 -13); with consistency seen across Scandinavia and UK. Dysregulated loci demonstrate strong genetic influence, notably VMP1 (p=1.53×10 -15). Age acceleration is seen in IBD (coefficient 0.94, p<2.2x10 -16). Several immuno-active genes demonstrated highly significant correlations between methylation and gene expression in IBD, in particular OSM: IBD r -0.32, p 3.64×10 -7 vs. non-IBD r -0.14, p=0.77). Multi-omic integration of methylome, genome and transcriptome also implicate specific pathways that associate with immune activation, response and regulation at disease inception. At follow up, a signature of 3 DMPs (TAP1, TESPA1, RPTOR) associated with treatment escalation to biological agents or surgery (hazard ratio of 5.19 (CI:2.14-12.56, logrank p=9.70×10 -4).CONCLUSION: These data demonstrate consistent epigenetic alterations at diagnosis in European patients with IBD, providing insights into the pathogenetic importance and translational potential of epigenetic mapping in complex disease.
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| 8. |
- Kalman, Thordis Disa, 1959-
(författare)
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Surgery and stomas in Crohn's disease
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study investigates the evolution of abdominal surgery in treatment of Crohn´s disease (CD) in the era of immunomodulatory drugs and biologicals. It concerns risk of abdominal surgery overall and sub-categories of abdominal surgery, risk of repeat surgery and factors that affect this risk, and risk of getting a stoma. Surgical recurrence is a major clinical problem as repeat procedures are more complex and expose the patients to a higher medical risk both in conjunction with surgery and afterwards. Updated information on abdominal surgery for CD will be of use when making decisions about medical vs surgical interventions.In a nationwide cohort of 21 273 patients with CD during the years 1990-2014, the cumulative incidence of abdominal surgery within five years of diagnosis decreased continuously down to 17.3% for patients diagnosed with CD during the last calendar period of study, 2009–2014. Ileocecal resection was the most common primary procedure. The incidence of colectomy was low in all calendar periods and continuously decreased. The incidence of proctectomy was very low even after decades with the disease, 3.0% for patients diagnosed 1990-1995 with a median follow-up of 21 years. Incidence of repeat abdominal surgery within five years of primary procedure decreased in the 90s down 16.0% in the 1996– 2000 period with a risk of ileocolic reresection of 4.4%. After 2000, despite introduction of biologicals in 1998, no further significant decrease in repeat surgery was observed.In a retrospective review of prospectively maintained databases at three university hospitals, the rate of surgical recurrence for 389 patients with CD who had been treated with a primary ileocecal resection between 2000-2012 was investigated. The patients were operated receiving either a temporary stoma (20%) or a primary anastomosis (80%) with a median follow-up time of 105 months. Patients selected to temporary stoma had a higher prevalence of baseline risk factors usually associated with an increased risk of recurrence such as penetrating disease behaviour. Despite this, there was no difference in long-term surgical recurrence between the one- and two-stage groups; 18% vs 16%.In a retrospective review of prospectively maintained databases at two university hospitals, the effect of smoking cessation on rate of surgical recurrence was assessed. 242 patients were included with a median follow-up of 112 months. Surgical recurrence rate for smokers vs quitters was 16/42 (38%) vs 3/31 (10%); p = 0.02; risk ratio = 3.9 despite a median time for smoking exposure after the primary procedure of three years. Among the non-smokers 28/169 (17%) had a surgical recurrence at last follow-up. 8 out of 11 smoking patients who needed a second resection went on to need a third resection. Of the patients who were free of surgical recurrence at follow-up, those who had quit smoking were significantly less likely to have been put on medical therapy compared with smokers with a risk ratio of 3.2.In an observational study of a nationwide cohort of 19 146 patients with incident CD 2002- 2013 and followed through 2017, the incidence and prevalence of stoma was investigated. The cumulative incidence of stoma formation within five years was 2.4% and remained constant from 2002 and onwards although cumulative ever-use of biologicals increased and time to start with treatment with biologicals decreased. 48% of all stomas were reversed. Ileostomies encompassed about two-thirds of all stomas and risk of stoma was higher among patients with elderly-onset CD and among patients with perianal manifestations of the disease. 28% of the patients who underwent surgery with formation of a stoma had perianal disease. 0.6% of all incident patients had a permanent stoma five years after diagnosis.
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| 9. |
- Katinios, Georgios, et al.
(författare)
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Increased Colonic Epithelial Permeability and Mucosal Eosinophilia in Ulcerative Colitis in Remission Compared With Irritable Bowel Syndrome and Health
- 2020
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Ingår i: Inflammatory Bowel Diseases. - : Oxford University Press. - 1078-0998 .- 1536-4844. ; 26:7, s. 974-984
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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.
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| 10. |
- Keita, Åsa, 1973-, et al.
(författare)
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Increased uptake of non-pathogenic E. coli via the follicle-associated epithelium in longstanding ileal Crohn's disease
- 2008
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Ingår i: Journal of Pathology. - : Wiley. - 0022-3417 .- 1096-9896. ; 215:2, s. 135-144
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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.
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