Epithelial barrier dysfunction in lymphocytic colitis through cytokine-dependent internalization of claudin-5 and -8.

BACKGROUND: Watery diarrhea is the cardinal symptom of lymphocytic colitis (LC). We have previously shown that colonic Na malabsorption is one of the major pathologic alterations of LC and found evidence for an epithelial barrier defect. On these grounds, this study aimed to identify the inherent mechanisms of this epithelial barrier dysfunction and its regulatory features. METHODS: Epithelial resistance (R epi) was determined by one-path impedance spectroscopy and 3H-mannitol fluxes were performed on biopsies from sigmoid colon in miniaturized Ussing chambers. Tight junction proteins were analyzed by Western blot and confocal microscopy. Inflammatory signaling was characterized in HT-29/B6 cells. Apoptosis and mucosal surface parameters were quantified morphologically. RESULTS: R epi was reduced to 53% and 3H-mannitol fluxes increased 1.7-fold in LC due to lower expression of claudin-4, -5, and -8 and altered subcellular claudin-5 and -8 distributions off the tight junction. TNFα and IFNγ could mimic subcellular redistribution in HT-29/B6 cells, a process which was independent on MLCK activation. Epithelial apoptosis did not contribute to barrier dysfunction in LC and mucosal surface area was unchanged. CONCLUSIONS: Epithelial barrier dysfunction in LC occurs through downregulation of claudin-4, -5, and -8, and redistribution of claudin-5 and -8 off the tight junction, which contributes to diarrhea by a leak-flux mechanism. The key effector cytokines TNFα and IFNγ turned out to be the trigger for redistribution of claudin-5 and -8. Thus, alongside sodium malabsorption, leak-flux is yet another important diarrheal mechanism in LC.

Long-term prognosis of clinical symptoms and health-related quality of life in microscopic colitis: a case-control study.

BACKGROUND: Microscopic colitis, comprising collagenous colitis (CC) and lymphocytic colitis (LC), is a common cause of chronic diarrhoea. The long-term prognosis is not well described. AIM: To study outcome of symptoms and health-related quality of life (HRQoL). METHODS: A case-control study using a postal questionnaire with three population-based controls per patient matched for age, sex and municipality. HRQoL was assessed by the Short Health Scale (SHS). Patients in clinical remission, defined as a mean of <3 stools/day, were evaluated separately (CC; n = 72, LC; n = 60). RESULTS: The study included 212 patients and 627 matched controls. Median disease duration was 5.9 (range 0.5-27) years and 6.4 (0.3-14.8) years for CC and LC respectively. Abdominal pain, fatigue, arthralgia, myalgia, faecal incontinence and nocturnal defecation were significantly more prevalent in CC patients compared with controls. These differences persisted in CC patients in clinical remission with respect to abdominal pain (36% vs. 21%), fatigue (54% vs. 34%), arthralgia (61% vs. 41%) and myalgia (53% vs. 37%). In LC patients, abdominal pain, fatigue, faecal incontinence and nocturnal defecation were more prevalent compared with controls. In LC patients in clinical remission, fatigue was more prevalent compared with controls (54% vs. 37%). These differences were statistically significant (P < 0.05). All four HRQoL dimensions (symptom burden, social function, disease-related worry, general well-being) were impaired in patients with active CC and LC. CONCLUSIONS: Although considered to be in clinical remission, patients with microscopic colitis suffer from persisting symptoms such as abdominal pain, fatigue, arthralgia or myalgia several years after diagnosis.

Microscopic colitis.

Microscopic colitis is a frequent cause of chronic watery diarrhea, especially in older persons. Common associated symptoms include abdominal pain, arthralgias, and weight loss. The incidence of microscopic colitis had been increasing, although more recent studies have shown a stabilization of incidence rates. The diagnosis is based on characteristic histologic findings in a patient with diarrhea. Microscopic colitis can occur at any age, including in children, but it is primarily seen in the elderly. Several treatment options exist to treat the symptoms of microscopic colitis, although only budesonide has been well studied in randomized clinical trials.

Clinical features and treatment responses in pediatric lymphocytic and collagenous colitis.

OBJECTIVE: Microscopic colitis (MC) is prevalent in adults investigated for chronic watery diarrhea, yet characterization of pediatric MC is limited. METHODS: Our pathology database was searched from 1995 to 2011 for pediatric cases of lymphocytic colitis (LC) or collagenous colitis (CC). Those with diarrhea persisting for >2 weeks and visually normal colonoscopy were accepted as cases. Demographics, laboratory results, medication use within 3 months of presentation, medical and family history of autoimmune disease, and response to treatment were abstracted. RESULTS: A total of 27 cases were histologically consistent with MC on biopsy; 5 with concomitant enteric infection or isolated abdominal pain were excluded. Twenty-two cases of MC (female patients, 59%; median age at diagnosis, 15.3 years) were included (19 LC and 3 CC). Two had type 1 diabetes mellitus, 2 were anti-nuclear antibody positive, and 2 had common variable immunodeficiency. Of 20 patients who underwent an esophagogastroduodenoscopy, 1 had collagenous sprue and 4 had celiac disease. One presented after the clearance of recurrent Clostridium difficile infection. Previous drug exposures included nonsteroidal anti-inflammatory drugs (n = 7), proton pump inhibitors (n = 6), and selective serotonin reuptake inhibitors (n = 3). Common symptoms in addition to diarrhea included abdominal pain (77.3%) and weight loss (27.3%). Of 17 patients with follow-up, all of the 8 treated with steroids had some response: 57.1% (4/7) responded to mesalamine and 42.9% (3/7) responded to bismuth subsalicylate. CONCLUSIONS: In this cohort of pediatric patients, LC was much more common than CC. As described in adults, we observed associations with celiac disease, type 1 diabetes mellitus, and medications; we additionally saw an association with immunodeficiency. Our patients showed greater response to steroids than mesalamine or bismuth.

Microscopic colitis as a missed cause of chronic diarrhea.

AIM: To determine the prevalence of increased intraepithelial lymphocytes, using immunohistochemistry in patients with normal colonoscopy and near normal biopsy. METHODS: We retrospectively reviewed all non-malignant colon mucosal biopsies between 2005 and 2007, reported as normal, chronic inflammation or melanosis coli in patients who were undergoing routine colonoscopy. Immunohistochemistry using CD3 was performed on all mucosal biopsies and an intraepithelial lymphocyte count (IEL) was determined. Cases with an IEL count of ≥ 20 IELs per 100 surface epithelial cells were correlated with demographic, clinical and follow-up data. A further subgroup was evaluated for lymphocytic colitis. RESULTS: Twenty (8.3%) of 241 cases revealed an IEL count ≥ 20. Six (2.5%) patients were identified as having lymphocytic colitis (P < 0.001), of whom, five were missed on initial evaluation (P = 0.01). Four of these five patients were labeled with diarrhea-predominant irritable bowel syndrome (IBS). On follow-up, three of the remaining 20 cases were diagnosed with malignancy (renal cell carcinoma and myelodysplastic syndrome) and one had an unknown primary tumor with multiple liver metastases. Two cases of collagenous colitis with an IEL count < 10 were included in this study. Increased IELs were not confined to patients with diarrhea as a primary presenting symptom, but were also present in patients with abdominal pain (n = 7), constipation (n = 3) and loss of weight (n = 1). CONCLUSION: Immunohistochemistry using CD3 is of value in identifying and quantifying IELs for the presence of microscopic colitis in patients with diarrhea-predominant IBS.

A retrospective study on a cohort of patients with lymphocytic colitis

Objective: the term “microscopic colitis” includes lymphocytic colitis (LC) and collagenous colitis, bearing common clinical presentation distinguishable only by histopathological examination of colonic biopsies. This study reports on demographic and clinical characteristics, and outcome of a cohort of patients with LC. Methods: demographic, clinical and histopathological data were reviewed. Every patient underwent total colonoscopy with multiple biopsies examined by an expert pathologist. Diagnosis of LC was confirmed if histopathological criteria were present. Routine laboratory tests were collected to rule out other diagnosis. Results: we included 80 patients (28 males; mean age: 46.4 years). At diagnosis, 71 patients (88%) reported diarrhea, 46 (58%) abdominal pain, 21 (36%) weight loss, 10 (13%) nausea. Regarding autoimmune or inflammatory diseases accompanying LC, thyroid disorders and celiac disease (CD) ranked first. Moreover, in over 10% of patients who underwent esophagogastroduodenoscopy, duodenal biopsies showed villi alterations classified as Marsh I damage, without clinical and serological data for diagnosis of CD. Mesalazine and oral topical steroids (budesonide or beclomethasone) were used to treat LC in 34 (43%) and 32 (39%) of patients, respectively, with similar percentages of clinical response (approximately 80%). Conclusions: the need for total colonoscopy with multiple biopsies in all patients with chronic watery diarrhea was confirmed. Since the association between CD and LC exists, additional tests should be performed in patients not responding to glutenfree diet or to LC specific therapy to exclude the other condition. Mesalazine obtained a similar outcome than oral steroids in this cohort(AU)

Vascular microarchitecture of murine colitis-associated lymphoid angiogenesis.

In permissive tissues, such as the gut and synovium, chronic inflammation can result in the ectopic development of anatomic structures that resemble lymph nodes. These inflammation-induced structures, termed lymphoid neogenesis or tertiary lymphoid organs, may reflect differential stromal responsiveness to the process of lymphoid neogenesis. To investigate the structural reorganization of the microcirculation involved in colonic lymphoid neogenesis, we studied a murine model of dextran sodium sulfate (DSS)-induced colitis. Standard 2-dimensional histology demonstrated both submucosal and intramucosal lymphoid structures in DSS-induced colitis. A spatial frequency analysis of serial histologic sections suggested that most intramucosal lymphoid aggregates developed de novo. Intravital microscopy of intravascular tracers confirmed that the developing intramucosal aggregates were supplied by capillaries arising from the quasi-polygonal mucosal plexus. Confocal optical sections and whole mount morphometry demonstrated capillary networks (185 +/- 46 microm diameter) involving six to ten capillaries with a luminal diameter of 6.8 +/- 1.1 microm. Microdissection and angiogenesis PCR array analysis demonstrated enhanced expression of multiple angiogenic genes including CCL2, CXCL2, CXCL5, Il-1b, MMP9, and TNF within the mucosal plexus. Intravital microscopy of tracer particle flow velocities demonstrated a marked decrease in flow velocity from 808 +/- 901 microm/sec within the feeding mucosal plexus to 491 +/- 155 microm/sec within the capillary structures. We conclude that the development of ectopic lymphoid tissue requires significant structural remodeling of the stromal microcirculation. A feature of permissive tissues may be the capacity for lymphoid angiogenesis.

Microscopic colitis: an update.

Microscopic colitis (MC) causes chronic diarrhea, abdominal cramping, nausea, and weight loss. Colonic mucosa appears normal on endoscopy; however, biopsies show abnormalities such as intraepithelial lymphocytosis in lymphocytic colitis, and a thickened subepithelial collagen band in collagenous colitis. Epidemiologic data demonstrates that MC is a more common cause of diarrhea than previously shown. Although the etiology of this condition is unclear, certain well-defined risk factors exist. Recently there has been more research on the pathophysiology of MC, and studies on treatment have demonstrated budesonide to be most effective, although other treatments also hold promise.

Mechanism of diarrhea in microscopic colitis.

AIM: To search the pathophysiological mechanism of diarrhea based on daily stool weights, fecal electrolytes, osmotic gap and pH. METHODS: Seventy-six patients were included: 51 with microscopic colitis (MC) (40 with lymphocytic colitis (LC); 11 with collagenous colitis (CC)); 7 with MC without diarrhea and 18 as a control group (CG). They collected stool for 3 d. Sodium and potassium concentration were determined by flame photometry and chloride concentration by titration method of Schales. Fecal osmotic gap was calculated from the difference of osmolarity of fecal fluid and double sum of sodium and potassium concentration. RESULTS: Fecal fluid sodium concentration was significantly increased in LC 58.11+/-5.38 mmol/L (P<0.01) and CC 54.14+/-8.42 mmol/L (P<0.05) than in CG 34.28+/-2.98 mmol/L. Potassium concentration in LC 74.65+/-5.29 mmol/L (P<0.01) and CC 75.53+/-8.78 mmol/L (P<0.05) was significantly less compared to CG 92.67+/-2.99 mmol/L. Chloride concentration in CC 36.07+/-7.29 mmol/L was significantly higher than in CG 24.11+/-2.05 mmol/L (P<0.05). Forty-four (86.7%) patients had a secretory diarrhea compared to fecal osmotic gap. Seven (13.3%) patients had osmotic diarrhea. CONCLUSION: Diarrhea in MC mostly belongs to the secretory type. The major pathophysiological mechanism in LC could be explained by a decrease of active sodium absorption. In CC, decreased Cl/HCO3 exchange rate and increased chloride secretion are coexistent pathways.