Microscopic colitis

SARS-CoV-2 as a potential trigger for microscopic colitis in a young adult: A case report

This case highlights the potential role of SARS-CoV-2 in triggering lymphocytic colitis, emphasizing the need for further research and vigilance in identifying potential post-COVID-19 GI complications. We describe a case of a young adult who experienced chronic diarrhea and abdominal pain for 10 months after a SARS-CoV-2 infection. Extensive laboratory and imaging investigations yielded no significant findings. Despite a preliminary diagnosis of irritable bowel syndrome and symptomatic treatment, symptoms persisted. Colonoscopy with biopsies revealed unremarkable colonic mucosa but confirmed moderate lymphocytic infiltration consistent with lymphocytic colitis. Treatment with budesonide achieved complete symptom resolution. The findings underscore the importance for clinicians to consider triggered microscopic colitis in patients presenting with persistent diarrhea following SARS-CoV-2 infection.

Trans-Anethole Alleviates DSS-Induced Ulcerative Colitis by Remodeling the Intestinal Flora to Regulate Immunity and Bile Acid Metabolism

Ulcerative colitis (UC) is the most common inflammatory bowel disease (IBD); it is incurable, and the treatment is expensive. Trans-anethole (TA), the main component of fennel, exhibits various biological activities. An increasing number of studies have demonstrated the efficacy of herbal active ingredients in the treatment of UC. This study aimed to investigate the effect and mechanism of TA in UC. In this study, we have experimented on mice with dextran sulfate sodium salt (DSS)-induced UC. The TA group was gavaged with 62.5 mg/kg TA by gavage once daily on days 8-14. To observe the effect of TA on the colon tissue, various investigations were performed, including western blot and immunohistochemistry for intestinal barrier protein expression, TUNEL staining for apoptosis, western blot, and ELISA for inflammation level, flow cytometry for Th17/Treg, LC-MS for blood bile acid content, GC-MS for blood fatty acid content, and 16s RNA for intestinal contents. TA alleviated weight loss in mice with UC; increased colon length; alleviated intestinal mucosal damage; upregulated claudin-1, occludin, and ZO-1 protein expression levels; reduced inflammatory factors in the colon and serum; and alleviated apoptosis. TA reduced fatty acid and bile acid levels by inhibiting colony abundance and reducing Th17/Treg cell differentiation in the colon. We found that TA alleviates DSS-induced UC by remodeling the intestinal flora to regulate immunity and bile acid metabolism.

Microscopic Colitis: Pathogenesis and Diagnosis

Microscopic colitis is a type of inflammatory bowel disease and is classified as either collagenous colitis or lymphocytic colitis. The typical presentation is chronic watery diarrhea. The disease occurs more frequently in women aged 60-65 years and is increasing in incidence. The pathophysiology of microscopic colitis remains poorly understood and has not been well-described with possible several pathogeneses. To date, the diagnosis of microscopic colitis depends on histological tissue obtained during colonoscopy. Other non-invasive biomarkers, such as inflammatory markers and fecal biomarkers, have been studied in microscopic colitis, but the results remains inconclusive. The approach to chronic diarrhea is important and being able to differentiate chronic diarrhea in patients with microscopic colitis from other diseases, such as inflammatory bowel disease, functional diarrhea, and malignancy, by using non-invasive biomarkers would facilitate patient management. The management of microscopic colitis should be based on each individual's underlying pathogenesis and involves budesonide, bile acid sequestrants, or immunosuppressive drugs in refractory cases. Cigarette smoking and certain medications, especially proton pump inhibitors, should be eliminated, when possible, after the diagnosis is made.

[Immunopathology of the small intestine]

The gastrointestinal tract is the site of exciting immunological interactions between the epithelium and the mucosa-associated lymphoid tissue, leading to the immune response to food and microbial antigens in the digestive lumen. The objective of this review is to present the main dysimmune pathologies of the digestive tract leading to an enteropathy. As examples, we describe celiac and non-celiac enteropathies to clarify a florid diagnostic framework, by identifying a spectrum of elementary lesions, which must be confronted with the clinico biological context of the patient to orient the diagnosis. The microscopic lesions observed are most often non-specific and may be encountered in several diagnostic settings. Moreover, it is a set of elementary lesions in each clinical context that will orient the diagnostic framework. Celiac disease is the main etiology of enteropathy with villous atrophy, its diagnosis is multidisciplinary and there are many differential diagnoses. We will discuss celiac disease lymphomatous complications as enteropathy associated T-cell lymphoma including refractory sprue type 2. We will then present the non-celiac enteropathies. Among these, enteropathies of unknown etiology may be associated with a primary immune deficiency that may be reflected by florid lymphoid hyperplasia of the gastrointestinal tract and/or be associated with an infectious etiology that should also be constantly sought. Finally, we will discuss of induced enteropathy by new immunomodulatory treatments.

Microscopic colitis: Etiopathology, diagnosis, and rational management

Microscopic colitis is an inflammatory bowel disease divided into two subtypes: collagenous colitis and lymphocytic colitis. With an increasing incidence of microscopic colitis exceeding those of ulcerative and Crohn's disease among elderly people in some countries, microscopic colitis is a debilitating life experience. Therefore, physicians should be familiar with its clinical features and management strategies because the disease deserves the same attention as the classical inflammatory bowel diseases. Here, state-of-the-art knowledge of microscopic colitis is provided from a global perspective with reference to etiopathology and how to establish the diagnosis with the overall aim to create awareness and improve rational management in clinical practice. The immune system and a dysregulated immune response seem to play a key role combined with risk factors (e.g. cigarette smoking) in genetically predisposed individuals. The symptoms are characterized by recurrent or chronic nonbloody, watery diarrhea, urgency, weight loss, and a female preponderance. As biomarkers are absent, the diagnosis relies on colonoscopy with a histological assessment of biopsy specimens from all parts of the colon. Although the disease is not associated with a risk of colorectal cancer, a recent nationwide, population-based cohort study found an increased risk of lymphoma and lung cancer. Budesonide is the first-line therapy for management, whereas immunomodulatory drugs (including biologics) and drugs with antidiarrheal properties may be indicated in those failing, dependent, or intolerant to budesonide. In microscopic colitis induced by checkpoint inhibitors, a drug class used increasingly for a wide range of malignancies, a more aggressive therapeutic approach with biologics introduced early seems reasonable. However, particular attention needs to be drawn to the existence of incomplete forms of microscopic colitis with the risk of being overlooked in routine clinical settings.

Pathogenesis of Microscopic Colitis: A Systematic Review

BACKGROUND

Whereas the exact aetiology of microscopic colitis [MC] remains unknown, a dysregulated immune response to luminal factors or medications is the most accepted pathogenesis hypothesis.

METHODS

We conducted a systematic review of the pathogenesis of MC. We applied the Joanna Briggs Institute methodologies and the PRISMA statement for the reporting of systematic reviews [PROSPERO Trial Identifier: CRD42020145008]. Populations, Exposure of interest, and Outcome [PEO] questions were used to explore the following topics in MC: 1] intestinal luminal factors; 2] autoimmunity; 3] innate immunity; 4] adaptive immunity; 5] extracellular matrix; 6] genetic risk factors; and 7] mechanism of diarrhoea. A search was done in PubMed, Embase, and Web of Science up to February 2020. A narrative description was performed explaining the findings for each aspect of MC aetiopathogenesis.

RESULTS

Thirty-eight documents provided evidence for PEO1, 100 for PEO2, 72 for PEO3 and 4, 38 for PEO5, 20 for PEO6, and 23 for PEO7. The majority of documents were cohorts, case reports, and case series, with a few case-control and some experimental studies. Consistency among data provided by different studies was considered to support pathogenetic hypotheses. MC is a multifactorial disease believed to involve innate and adaptive immune responses to luminal factors, genetic risk, autoimmunity, and extracellular matrix alterations, all contributing by varied mechanisms to watery diarrhoea.

CONCLUSIONS

This is the first systematic review on the aetiology of MC supporting the notion that MC is a multifactorial disease. However, high-profile studies are lacking, and most evidence derives from small heterogeneous studies.

Gastroprotective Effect of Enteral Nutrition Formula in Mice Injected Subcutaneously with Indomethacin

We have previously shown that two enteral nutrition formulas suppressed gastric lesions induced by the oral administration of indomethacin (IND) in mice. However, the mechanism of their protective effect is unknown. In this study, the effect of the two enteral nutrition formulas on gastric lesions induced by subcutaneous IND injection was investigated, with the objective of exploring the possibility that they may interact directly with IND in the gastrointestinal tract. Ten-week-old, male, ICR mice were fasted, then orally given either purified water, Mermed^® One, or 2-fold diluted Terumeal^® 2.0α as enteral nutrition formula (25 mL/kg). IND was injected subcutaneously at 20 mg/kg after 30 min, and the stomach was removed 6 h later and fixed in formalin. The number and area of lesions in the stomachs of mice given enteral nutrition formula was reduced to 56–89% and 34–61%, respectively, compared with the mice given purified water. The time courses of plasma IND concentrations were comparable among the three groups. These results suggested that the effect of these enteral nutrition formulas on gastric lesions did not originate from their direct interaction with IND in the gastrointestinal tract or their effect on the disposition of IND.

Adult autoimmune enteropathy in autoimmune hepatitis patient. Case report and literature review

Autoimmune enteropathy (AIE) is a rare disease characterized by prolonged diarrhea, vomiting and weight loss; although it is mainly a rare pediatric disease, over the years a number of adults have also been found to be affected. In this study, we present a case report of a 73-year-old woman with a history of autoimmune hepatitis, antinuclear (ANA) and positive anti-enterocyte antibodies (AEA), who has suffered two months of intractable diarrhea, nausea, anorexia and severe weight loss. The histological examination of the endoscopic duodenal mucosa biopsies revealed severe shortening and flattening of the villi, resulting in mucosal atrophy. The immunohistochemical study revealed a polymorphic lymphoid population, exhibiting a B cell (CD20+) phenotype in follicles and a T cell phenotype (CD3+) in the diffuse component within the lamina propria. Our patient had a complete recovery after two weeks of taking prednisone and following a gluten-rich diet. To our knowledge this is the first case of autoimmune enteropathy in adults with ANA and AEA 7 years after a diagnosis of autoimmune hepatitis. To date, the patient is still in clinical remission on a low dose of orally administered predinisone without any additional immunosuppression.

Recommendations for the diagnosis and management of transthyretin amyloidosis with gastrointestinal manifestations

Transthyretin amyloid (ATTR) amyloidosis is an adult-onset, rare systemic disorder characterized by the accumulation of misfolded fibrils in the body, including the peripheral nerves, the heart and the gastrointestinal tract. Gastrointestinal manifestations are common in hereditary (ATTRv) amyloidosis and are present even before the onset of the polyneuropathy in some cases. Delays in diagnosis of ATTRv amyloidosis with gastrointestinal manifestations commonly occur because of fragmented knowledge among gastroenterologists and general practitioners, as well as a shortage of centers of excellence and specialists dedicated to disease management. Although the disease is becoming well-recognized in the societies of Neurology and Cardiology, it is still unknown for most gastroenterologists. This review presents the recommendations for ATTRv amyloidosis with gastrointestinal manifestations elaborated by a working group of European gastroenterologists and neurologists, and aims to provide digestive health specialists with an overview of crucial aspects of ATTRv amyloidosis diagnosis to help facilitate rapid and accurate identification of the disease by focusing on disease presentation, misdiagnosis and management of gastrointestinal symptoms.

Controversial Contribution of Th17/IL-17 Toward the Immune Response in Intestinal Fibrosis

Intestinal fibrosis is a common outcome of inflammatory bowel diseases (IBDs), becoming clinically apparent in 40% of patients with Crohn's disease and 5% of those with ulcerative colitis. Effective pharmacological treatments aimed at controlling or reversing fibrosis progression are unavailable. Fibrosis is characterized by an excessive local accumulation of extracellular matrix proteins (mainly collagen), as a result of their increased production by activated myofibroblasts and/or their reduced degradation by specific matrix metalloproteinases. Initiation and progression of fibrosis are modulated by several pro- and anti-fibrogenic molecules. In recent years, the cytokine interleukin-17 (IL-17) has been integrated into the pathogenesis of fibrosis, although its precise contribution to IBD, and especially to its related intestinal fibrosis, remains controversial. Several data suggest both a pro-inflammatory and pro-fibrotic action and a protective function of the Th17/IL-17 immune response. A recent study has demonstrated that the treatment with anti-IL-17 antibody significantly alleviated 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colorectal fibrosis in mice by down-regulating the expression of collagen 3 and several pro-fibrogenic cytokines. Here, we describe and discuss the possible involvement of the Th17/IL-17 immune response in the initiation ad progression of intestinal fibrosis.

Study of the Inhibitory Effects of Enteral Nutrition Formula on Indomethacin-Induced Gastric Lesions in Mice

We investigated the effects of enteral nutrition formula on non-steroidal anti-inflammatory drug (NSAID)-induced gastric lesions in mice. Male ICR mice aged 7–9 weeks old were fasted, then orally given either purified water, Mermed^® One, or 2-fold diluted Terumeal^® 2.0α as enteral nutrition (25 or 50 mL/kg each). Indomethacin (IND) was orally administered at 20 mg/kg after 30 min, and the stomach was removed 6 h later and fixed in formalin. The number and area of lesions in the stomachs of the mice given enteral nutrition showed a significant, dose-dependent decrease compared to the purified water-treated group, and no significant difference was seen between the two enteral nutrition-treated groups. Comparable time courses of plasma IND concentrations suggest that enteral nutrition does not inhibit gastrointestinal absorption of IND. Our findings indicate that administering enteral nutrition could inhibit the onset of NSAID-induced gastric ulcers.

Genome-Wide Association Study of Microscopic Colitis in the UK Biobank Confirms Immune-Related Pathogenesis

BACKGROUND AND AIMS

The causes of microscopic colitis are currently poorly understood. Previous reports have found clinical associations with coeliac disease and genetic associations at the human leukocyte antigen [HLA] locus on the ancestral 8.1 haplotype. We investigated pharmacological and genetic factors associated with microscopic colitis in the UK Biobank.

METHODS

In total, 483 European UK Biobank participants were identified by ICD10 coding, and a genome-wide association study was performed using BOLT-LMM, with a sensitivity analysis performed excluding potential confounders. The HLA*IMP:02 algorithm was used to estimate allele frequency at 11 classical HLA genes, and downstream analysis was performed using FUMA. Genetic overlap with inflammatory bowel disease [Crohn's disease and ulcerative colitis] was investigated using genetic risk scores.

RESULTS

We found significant phenotypic associations with smoking status, coeliac disease and the use of proton-pump inhibitors but not with other commonly reported pharmacological risk factors. Using the largest sample size to date, we confirmed a recently reported association with the MHC Ancestral 8.1 Haplotype. Downstream analysis suggests association with digestive tract morphogenesis. By calculating genetic risk scores, we also report suggestive evidence of shared genetic risk with Crohn's disease, but not with ulcerative colitis.

CONCLUSIONS

This report confirms the role of genetic determinants in the HLA in the pathogenesis of microscopic colitis. The genetic overlap with Crohn's disease suggests a common underlying mechanism of disease.

Review of Drug-induced Injury in Mucosal Biopsies From the Tubular Gastrointestinal Tract

The use of prescription and over-the-counter medications is on the rise in the US population, especially among those aged 65 and over, with over 46% of the population taking at least 1 prescription medication. Given the frequency of medication use, and that the majority of these medications are taken orally, it has become increasingly relevant for pathologist examining endoscopically obtained gastrointestinal tract mucosal biopsies to consider and recognize patterns of mucosal injury associated with various drugs. Reports on injuries associated with certain classes of drugs can be scattered among different sources, making a comprehensive view of various injury patterns and the drugs known to cause them difficult to obtain. Herein, we provide a comprehensive overview of the drugs known to cause mucosal injuries in the tubular gastrointestinal tract organized by the organ involved and the prominent pattern of injury.

Research progress and perspectives of microscopic colitis

Microscopic colitis (MC) is a common cause of chronic diarrhea. Over the past 20 years, the prevalence of MC has been increasing rapidly, which has aroused the close attention of digestive physicians. The etiology of MC is still unknown, and immune abnormalities are the main pathogenesis, followed by some drugs. MC is clinically characterized by chronic non-bloody watery diarrhea, spastic abdominal pain, weight loss, and fatigue, but colonoscopy is often normal or roughly normal. Colonic biopsy often shows mucosal inflammation or subepithelial collagen band thickening, based on which a diagnosis can be made. At present, there has been no special treatment for MC, with steroid budesonide and immunosuppressive agents being the main treatments. As a self-limiting disease, MC has a good prognosis. Studies have found that MC has a protective effect against colorectal cancer. However, it was recently found that innate immune abnormalities may have carcinogenic effects.

Proton pump inhibitor induced collagen expression in colonocytes is associated with collagenous colitis

AIM

To elucidate the role of proton pump inhibitors (PPIs) in collagenous disease, direct effect of PPI on colonocytes was examined.

METHODS

Collagenous colitis is a common cause of non-bloody, watery diarrhea. Recently, there has been increasing focus on the use of proton PPIs as a risk factor for developing collagenous colitis. Mouse CT26 colonic cells were treated with PPI and/or PPI-induced alkaline media. Expression of fibrosis-associated genes was examined by RT-PCR. In human materials, collagen expression was examined by immunohistochemistry.

RESULTS

CT26 cells expressed a Na⁺-H⁺ exchanger gene (solute carrier family 9, member A2). Treatment with PPI and/or PPI-induced alkaline media caused growth inhibition and oxidative stress in CT26 cells. The treatment increased expression of fibrosis inducing factors, transforming growth factor β and fibroblast growth factor 2. The treatment also decreased expression of a negative regulator of collagen production, replication factor C1, resulting in increased expression of collagen types III and IV in association with lipid peroxide. In biopsy specimens from patients with collagenous colitis, type III and IV collagen were increased. Increase of type III collagen was more pronounced in PPI-associated collagenous colitis than in non-PPI-associated disease.

CONCLUSION

From these findings, the reaction of colonocytes to PPI might participate in pathogenesis of collagenous colitis.

Successful use of adalimumab in patient with treatment-refractory microscopic colitis

A 50-year-old woman with treatment-refractory lymphocytic colitis was diagnosed with ankylosing spondylitis. She was started on adalimumab injections which significantly improved her stool frequency and consistency and, consequently, her quality of life.

[Collagenous gastritis and colitis in a 10-year-old girl]

There are few data in the literature on microscopic gastritis and colitis in the pediatric population. The diagnosis is often made after the occurrence of complications. We report the case of a 10.5 year-old girl for whom the diagnosis was made several years after the initial symptoms. Test for infections, inflammation, and auto-immunity yielded normal results. Upper endoscopy and colonoscopy revealed an abnormal mucosa. However, histology showed microscopic inflammation and fibrotic lesions in the lamina propria, and a thick subepithelial collagenous band. This led to the diagnosis of collagenous gastritis and colitis. Budesonide treatment resulted in the cessation of diarrhea and significant weight gain. Treatment by oral budesonide indeed seems to be highly effective but relapses are frequent when the treatment is stopped. This case shows the importance of being vigilant regarding transit disorders with impact on growth kinetics. Upper endoscopy and colonoscopy need to be carried out when children have organic diarrhea with normal blood tests.

Advances for improved diagnosis of microscopic colitis in patients with chronic diarrhoea

Microscopic colitis is a generic term that includes 2 main forms, collagenous colitis and lymphocytic colitis, and describes a form of inflammatory bowel disease with a chronic and relapsing course. The incidence of microscopic colitis is between 2 and 8 times higher in women than in men, although age, more than sex, increases the risk of collagenous colitis (odds ratio [OR] 8.3 for age ≥65 vs. <65 and OR 2.8 for women). The main symptom is chronic non-bloody watery diarrhoea. Other common symptoms include abdominal pain (50%-70%), with the result that many patients with microscopic colitis meet criteria for irritable bowel syndrome. Colonoscopy with multiple colonic biopsies is currently recommended, as histological changes are the main characteristic feature. The colonic mucosa is macroscopically normal, although certain minimal endoscopic abnormalities have been described.

Current concepts on microscopic colitis: evidence-based statements and recommendations of the Spanish Microscopic Colitis Group

BACKGROUND

Microscopic colitis (MC) is an underdiagnosed inflammatory bowel disease.

AIM

To develop an evidence-based clinical practice guide on MC current concepts.

METHODS

Literature search was done on the Cochrane Library, EMBASE and MEDLINE electronic databases, which were consulted covering the period up until March 2015. Work groups were selected for each of the reviewed topics, with the purpose of drafting the initial statements and recommendations. They subsequently underwent a voting process based on the Delphi method. Each statement/recommendation was accompanied by the result of the vote the level of evidence, and discussion of the corresponding evidence. The grade of recommendation (GR) using the GRADE approach was established for diagnosis and treatment recommendations.

RESULTS

Some key statements and recommendations are: advancing age increases the risk of developing MC, mainly in females. The symptoms of MC and IBS-D may be similar. If MC is suspected, colonoscopy taking biopsies is mandatory. Treatment with oral budesonide is recommended to induce clinical remission in patients with MC. Oral mesalazine is not recommended in patients with collagenous colitis for the induction of clinical remission. The use of anti-TNF-alpha drugs (infliximab, adalimumab) is recommended for the induction of remission in severe cases of MC that fail to respond to corticosteroids or immunomodulators, as an alternative to colectomy.

CONCLUSIONS

This is the first consensus paper on MC based on GRADE methodology. This initiative may help physicians involved in care of these patients in taking decisions based on evidence.

Development and validation of a scoring system to identify patients with microscopic colitis

BACKGROUND & AIMS

Diarrhea is a common indication for colonoscopy. Biopsies are collected and analyzed from patients with a macroscopically normal colon to exclude microscopic colitis (MC), but the diagnostic yield is low because most patients have functional disease. We developed and validated a diagnostic scoring system to identify patients with MC to reduce the need to collect biopsies from all patients.

METHODS

We performed a retrospective study, which analyzed demographic and symptom data from adult patients with chronic diarrhea evaluated by colonoscopy and biopsy at 3 endoscopy centers in Leeds, United Kingdom. To derive the scoring system, we analyzed data from 476 adult patients (mean age, 53.6 years; 63.7% female) examined in 2011. Factors significantly associated with the presence of MC were assigned item scores, and total scores were determined for each patient. To validate the system, we used it to assess data from 460 patients (mean age, 52.9 years; 59.8% female) examined in 2012. The primary aim of the study was to determine the performance of the diagnostic scoring system in identifying patients with MC by using histologic findings as a reference.

RESULTS

In the derivation cohort, 85 patients were diagnosed with MC on the basis of histologic analysis. Age ≥50 years, female sex, use of proton pump inhibitors or nonsteroidal anti-inflammatory drugs, weight loss, and absence of abdominal pain were significantly associated with MC. We created a scoring system for diagnosis of MC, with scores ranging from -8 to +38; scores ≥8 were used to identify the presence of MC. This cutoff value identified patients with MC in the validation cohort (74 patients, 16.1%) with 90.5% sensitivity and 45.3% specificity (area under the receiver operating characteristic curve value, 0.76). Because of its ability to exclude MC and therefore avoid the need for routine collection of colonic biopsies, this scoring system reduced the cost of evaluation by >£7000 in the cohort.

CONCLUSIONS

We collected data on risk factors for MC to create a scoring system that identifies patients with MC with more than 90% sensitivity. This system can also reduce costs by identifying patients who are unlikely to have MC who do not require biopsy analysis.

Incidence, prevalence, and temporal trends of microscopic colitis: a systematic review and meta-analysis

OBJECTIVES

A systematic review and meta-analysis was conducted to provide an accurate estimate of the incidence rate of microscopic colitis (MC) and to assess the association between medication use and the risk of MC.

METHODS

We searched Medline, Embase, and Institute for Scientific Information (ISI) Web of Science up to 26 September 2014 to identify published epidemiological studies of MC. The pooled incidence rate, female-to-male incidence rate ratio, age at diagnosis, prevalence, as well as odds ratios (ORs) of MC in association with medication use were calculated using a fixed-effects model or a random-effects model.

RESULTS

Of the 1,972 citations retrieved, 25 studies were included. Pooled incidence rate of collagenous colitis (CC) was 4.14 (95% confidence interval (CI) 2.89-5.40) per 100,000 person-years and 4.85 (95% CI, 3.45-6.25) for lymphocytic colitis (LC). The female-to-male incidence rate ratios were 3.05 (95% CI 2.92-3.19) for CC and 1.92 (95% CI 1.53-2.31) for LC. The median age at diagnosis for CC was 64.9 (range, 57.03-72.78) years, similar to LC (median 62.18, range 53.99-70.38). Furthermore, the incidence rate of MC increased with rising age. A steadily increasing trend of incidence rate for both CC and LC was observed before 2000; however, the incidence rate since then has become stable in the United States, Sweden, and Spain. An increased risk of MC was associated with the use of proton pump inhibitors (PPIs) and selective serotonin reuptake inhibitors (SSRIs) (OR 2.68, 95% CI 1.73-4.17 and OR 2.41, 95% CI 1.64-3.53, respectively).

CONCLUSIONS

MC is a common disease process. Female gender, increased age, and the use of PPIs and SSRIs are associated with a significantly increased risk of developing MC. Further work is needed to evaluate reported data from developing countries and to elucidate the biologic mechanisms behind the risk factors for MC.

[Evolution of ideas on microscopic colitis]

The literature review gives the present-day views of the definition, etiology, pathogenesis, diagnosis, and treatment of microscopic colitis (MC). In the present view, MC is an inflammatory bowel disease of unknown etiology, which is characterized by chronic watery diarrhea, no macroscopic signs of large bowel involvement in the presence of specific pathomorphological changes. There are two major forms of MC, which are similar in its clinical picture, yet, heterogeneous in histological criteria: collagenous colitis (CC) and lymphocytic colitis (LC). As of now, the prevalence of MC is about 100 cases per 100,000 population, which is similar with that in other inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease. MC generally prevails in women aged over 50 years. The etiology and pathogenesis of MC have not fully investigated. Watery diarrhea is as a predominant pathognomonic symptom in all the patients with MC. The major histological criterion for the diagnosis of CC is subepithelial collagen lining thickening (more than 10 pm) and that for LC is higher intraepithelial lymphocyte counts (more than 20 intraepithelial lymphocytes/100 epitheliocytes). The topical glucocorticosteroid budesonide is currently the only agent, the efficacy of which has been proven in both inducing and maintaining remission in patients with MC in many clinical trials.

VSL#3 induces and maintains short-term clinical response in patients with active microscopic colitis: a two-phase randomised clinical trial

BACKGROUND

The probiotic mixture VSL#3 has proven efficacious in inflammatory bowel diseases and irritable bowel syndrome; however, its efficacy in microscopic colitis (MC) is being investigated.

OBJECTIVE

To evaluate the safety and efficacy of a multistrain probiotic, VSL#3, in inducing clinical remission and achieving clinical response, as compared with mesalamine, in patients with active MC.

METHODS

A randomised, open labelled study comparing the efficacy of 900 billion colony-forming units/day of VSL#3 (group (Gp) A) or 1.6 g of mesalamine/day (Gp B) for 8 weeks in 30 patients with MC was conducted. After a washout period of 2 weeks, Gp B received 8 weeks of VSL#3 and Gp A was off medication for the next 8 weeks. The primary end points were clinical remission and clinical response at 8 weeks.

RESULTS

Of 30 patients, 15 were randomised in each arm. 11 patients in Gp A and 13 patients in Gp B completed 8 weeks of treatment. 5 (46%) of 11 patients in Gp A and 1 (8%) of 13 patients in Gp B attained clinical remission (p=0.022). Clinical response was seen in Gp A, as evidenced by a lower stool weight (377.6±104.5 g) as compared with Gp B (507±168.2 g; p=0.03). VSL#3 was effective in maintaining clinical response up to 10 weeks, even after discontinuation of therapy. Secondary end points like stool parameters, histology and well-being improved in both treatment groups.

CONCLUSIONS

The probiotic VSL#3 was found to offer the benefit of inducing as well as maintaining short-term clinical response in patients with active MC.

TRIAL REGISTRATION NUMBER

The clinical trial is registered with CLINICAL TRIAL REGISTRY INDIA; http://ctri.nic.in, CTRI No. "CTRI/2008/091/000086" (registered on: 23/06/2008).

New insights and challenges in microscopic colitis

Microscopic colitis (MC) is described as an inflammatory bowel disease characterized by chronic, bloodless diarrhea with normal or close to normal endoscopic findings. Histopathological examination reveals two subtypes: collagenous colitis (CC) and lymphocytic colitis (LC), which are indistinguishable clinically. The disease debuts typically in middle-aged patients, but can occur at all ages, including children. A female predominance is found in both CC and LC, but is not confirmed by others in LC. The etiology is unclear, but the disease has been assumed to be of autoimmune origin. However, several etiologies may render a microscopic inflammation in the mucosa; this is a common, universal reaction to a variety of irritants in contact with the intestinal lumen. Furthermore, some patients with a microscopic inflammation in their colonic mucosa have no symptoms, or are suffering from constipation or abdominal pain, rather than diarrhea. Recently, a discussion was initiated calling into question the overdiagnosing of symptoms and pointing out the danger of exacerbating people's perception of their ailments, of weakening their eligibility in health insurance, of overprescription of drugs, and thus the increasing cost to the society of health care. In the light of this discussion, this review will highlight histopathological and clinical features of MC, and discuss the diagnosis and management of this disease. Perhaps, the intestinal mucosa has no other mode by which to react than an inflammatory response, irrespective of the presence or absence of autoimmunity. Thus, to better identify and classify subgroups of MC, and to clarify and correctly handle the inflammatory changes, this field of research stands to benefit from a review of the results and experience gained to date.

Efficacy of budesonide in collagenous colitis Evaluation of: Miehlke S, Madisch A, Kupcinskas L, et al. Budesonide is more effective than mesalamine or placebo in short-term treatment of collagenous colitis. Gastroenterology 2014;146(5):1222-1230 e1222

INTRODUCTION

Collagenous colitis (CC) is a less common colonic disease with variable prevalence and undulating course. Among the available therapies, budesonide was demonstrated to induce a rapid and sustained remission in many cases, but little is known about the comparative efficacy of other treatments, such as mesalamine.

AREAS COVERED

Evaluation of a randomized study assessing the efficacy and safety of budesonide over mesalamine in patients with CC.

EXPERT OPINION

Data from the study showed that budesonide was significantly superior to placebo and to mesalamine and further supports the recommendation of the current guidelines on the use of budesonide in CC. However, other forms of mesalamine may further be evaluated for this disease.

Diarrhea in solid-organ transplant recipients: a review of the evidence

OBJECTIVE

To provide a comprehensive review of the literature as it relates to diarrhea in solid organ transplant (SOT) recipients. In this article, we review the epidemiology, pathogenesis, clinical manifestations, diagnosis and management of diarrhea in SOT recipients and discuss recent advances and challenges.

METHODS

Two investigators conducted independent literature searches using PubMed, Web of Science, and Scopus until January 1st, 2013. All databases were searched using a combination of the terms diarrhea, solid organ transplant, SOT, transplant associated diarrhea, and transplant recipients. Articles that discussed diarrhea in SOT recipients were reviewed and relevant cross-references also read and evaluated for inclusion. Selection bias could be a possible limitation of the approach used in selecting or finding articles for this article.

FINDINGS

Post-transplant diarrhea is a common and distressing occurrence in patients, which can have significant deleterious effects on the clinical course and well-being of the organ recipient. A majority of cases are due to infectious and drug-related etiologies. However, various other etiologies including inflammatory bowel disease must be considered in the differential diagnosis. A step-wise, informed approach to post-transplant diarrhea will help the clinician achieve the best diagnostic yield. The use of diagnostic endoscopy should be preceded by exclusion of an infectious or drug-related cause of diarrhea. Empiric management with antidiarrheal agents, probiotics, and lactose-free diets may have a role in managing patients for whom no cause can be determined even after an extensive investigation.

CONCLUSIONS

Physicians should be familiar with the common etiologies that result in post-transplant diarrhea. A directed approach to diagnosis and treatment will not only help to resolve the diarrhea but also prevent potentially life-threatening consequences including loss of the graft as well. Prospective studies are required to determine the etiology of post-transplant diarrhea in different clinical and geographic settings.

Pre- and posttherapy assessment of intestinal soluble mediators in IBD: where we stand and future perspectives

Inflammatory bowel disease (IBD) is a chronic inflammatory condition characterized by an abnormal immune response against food or bacterial antigens in genetically predisposed individuals. Several factors of innate and adaptive immune system take part in the inflammatory process, probably actively contributing in endoscopic and histological healing at molecular level. Although it is difficult to discriminate whether they are primary factors in determining these events or they are secondarily involved, it would be interesting to have a clear map of those factors in order to have a restricted number of potentially "good candidates" for mucosal healing. The present review will present a class of these factors and their modulation in course of therapy, starting from pathogenic studies involving several treatments associated with good clinical outcomes. This approach is meant to help in the difficult task of identifying "good candidates" for healing signatures, which could also be possible new therapeutic targets for clinical management of IBD patients.

Microscopic colitis: epidemiology, pathophysiology, diagnosis and current management-an update 2013

Microscopic colitis is a common cause of chronic diarrhea. Over the last years the incidence and the prevalence of microscopic colitis are rising and this rise is largely attributed to a rising awareness, and concomitantly an increasing number of diagnoses are made. Patients with microscopic colitis report watery, nonbloody diarrhea of chronic, intermittent, or chronic recurrent course. Following an unremarkable physical examination the diagnosis of microscopic colitis is made by colonoscopy, which shows essentially a normal colonic mucosa. Biopsies taken during the colonoscopy procedure will then finally establish the correct diagnosis. Histological workup can then confirm a diagnosis of microscopic colitis and can distinguish the two distinct histological forms, namely, collagenous colitis and lymphocytic colitis. Presently both forms are diagnosed and treated in the same way; thus the description of the two forms is not of clinical value, though this may change in future. Depending on the patients age and gender 10-30% of patients investigated for chronic diarrhea will be diagnosed with microscopic colitis if biopsies are taken. Microscopic colitis is most common in older patients, especially in female patients and is frequently associated with autoimmune disorders and the consumption of several drugs. This review summarizes the present knowledge of the epidemiology, the pathophysiology, and the diagnosis of microscopic colitis and discusses the former and the present treatment options.