Biomarkers and Microscopic Colitis: An Unmet Need in Clinical Practice

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.

The Utility of Fecal Calprotectin in the Diagnosis and Management of Microscopic Colitis

Background

The incidence of microscopic colitis has increased over time. To date, there is no specific biomarker for microscopic colitis, and the diagnosis relies on histopathological tissue obtained during colonoscopy which is an invasive and costly procedure. Unlike Crohn's disease and ulcerative colitis, the utility of fecal calprotectin in diagnosing or monitoring microscopic colitis has not been established, and studies on the role of fecal calprotectin in microscopic colitis are limited. In this retrospective study, we analyzed the utility of this biomarker in the diagnosis of microscopic colitis.

Methods

The medical records of patients who have been diagnosed with collagenous colitis and lymphocytic colitis aged 18-89 years old were retrospectively reviewed. Patient characteristics were recorded in those who had fecal calprotectin measured.

Results

There were 198 patients who were diagnosed with collagenous colitis and lymphocytic between October 1, 2015, and July 31, 2022. Twenty-three patients had fecal calprotectin levels measured and were included in this study. The mean age was 51.7 ± 7.8 years in all groups. Thirteen patients were female. Six patients (26.1%) were diagnosed with collagenous colitis, and 17 patients (73.9%) were diagnosed with lymphocytic colitis. The fecal calprotectin cut-off in this lab is 50 μg/g stool. Median fecal calprotectin levels were 30.1 μg/g (15.6, 122.5), 19.5 μg/g (16.5, 64.6), and 33.2 μg/g (15.6, 134.9) in all groups, collagenous colitis, and lymphocytic colitis, respectively.

Conclusion

The utility of fecal calprotectin in diagnosing microscopic colitis is limited. Our study suggests the diagnosis should be based on histopathology tissue obtained during colonoscopy.

Fecal calprotectin level in microscopic colitis: a systematic review and meta-analysis

Background

There are no specific biomarkers for microscopic colitis (MC), and the diagnosis depends on histopathological tissue obtained during colonoscopy. Studies on the role of fecal calprotectin (FCP) in MC are limited. A literature search of PubMed, Embase, and Scopus was conducted from each database's inception through September 2022.

Methods

A DerSimonian-Liard random-effects meta-analysis was performed to examine the standardized mean difference (SMD) in FCP levels between patients with MC and control patients with chronic diarrhea.

Results

Six studies with 96 active MC patients and 200 controls were included in the meta-analysis. Random effects meta-analysis revealed that FCP was significantly and moderately elevated in patients with MC compared to the control group (SMD = 0.6 [95% CI 0.3, 1.0], P = 0.001). Imputing one effect size confirmed the observation that FCP is significantly higher in patients with MC than control subjects with chronic diarrhea (SMD = 0.5 [95% CI 0.2, 0.9], P = 0.004). Study heterogeneity between the SMDs was not significant (I2 = 41%, P = 0.1).

Conclusion

These results indicate that FCP levels in patients with chronic diarrhea can help identify patients with MC. More studies with serial measurements of FCP would provide a better understanding of its utility in MC.

Meta-analysis: Placebo rates in microscopic colitis randomised trials and applications for future drug development using a historical control arm

BACKGROUND

Effective medical therapies for patients with microscopic colitis (MC) who fail budesonide are lacking. However, conducting randomised controlled trials (RCTs) in MC has been challenging due to small sample sizes. Understanding placebo responses can help inform more efficient future trials.

AIMS

The aim of this study is to estimate clinical and histologic placebo response rates and to determine factors associated with placebo response in MC.

METHODS

EMBASE, MEDLINE, and CENTRAL were searched until 7 January 2022, to identify placebo-controlled RCTs in adult patients with MC. Clinical and histologic response in the placebo arms were pooled using random-effects models. Stratified analyses based on disease- and trial-level characteristics, leave-one-out meta-analysis, and cumulative meta-analysis were performed.

RESULTS

Twelve RCTs enrolling a total of 391 patients (placebo n = 163) with MC were included. Pooled clinical and histologic placebo response rates were 24.4% (95% CI: 12.4%-38.4%), I²  = 60.8%, p < 0.01, and 19.9% (95% CI: 5.3%-39.0%), I²  = 66.4%, p = 0.01 (tests for heterogeneity), respectively. Clinical response to placebo was numerically higher in patients with lymphocytic compared to collagenous colitis (39.9% vs. 19.8%, p = 0.08). Heterogeneity in clinical response to placebo was significantly reduced when the Miehlke 2014 RCT was excluded in the leave-one-out meta-analysis or when a more stringent secondary definition of response based on the Hjortswang criteria was applied.

CONCLUSIONS

Approximately one-quarter of patients in MC trials respond to placebo, although with substantial heterogeneity, reflecting the need for standardised outcome definitions and study designs for MC. This analysis also serves to inform future MC trials that may consider incorporating an external, historical placebo control arm, rather than directly randomising patients to placebo.

Reduced Intake of Dietary Tryptophan Improves Beneficial Action of Budesonide in Patients with Lymphocytic Colitis and Mood Disorders

Lymphocytic colitis (LC) is a gastrointestinal (GI) tract disease with poorly known pathogenesis, but some environmental and lifestyle factors, including certain dietary components, may play a role. Tryptophan is an essential amino acid, which plays important structural and functional roles as a component of many proteins. It is important in the development and maintenance of the body, in which it is metabolized in two main pathways: kynurenine (KYN) and serotonin. In this work, we explored the effect of reducing of TRP in the diet of patients with LC with mood disorders. We enrolled 40 LC patients who had a normal diet, 40 LC patients with the 8-week diet with TRP content reduced by 25% and 40 controls. All LC patients received budesonide at 9 mg per day, and the severity of their GI symptoms was evaluated by the Gastrointestinal Symptoms Rating Scale. Mood disorders were evaluated by the Hamilton Anxiety Rating Scale (HAM-A) and the Hamilton Depression Rating Scale (HAM-D). The concentration of TRP and its metabolites, 5-hydroxyindoleacetic acid (5-HIAA), kynurenine (KYN), kynurenic acid (KYNA) and quinolinic acid (QA), in urine were determined. Budesonide improved the GI and mental states of LC patients, and the diet with reduced TRP content further amended these symptoms. Dietary intervention decreased the concentration of 5-HIAA by about 50% (3.4 vs. 6.3) and QA by about 45% (3.97 vs. 7.20). These changes were correlated with a significant improvement in the profitable action of budesonide on gastrointestinal and mental health of LC patients as they displayed significantly lower GSRS, HAM-A and HAM-B scores after than before the intervention—10.5 vs. 32, 11.0 vs. 21 and 12 vs. 18, respectively. In conclusion, a reduction in TRP intake in diet may improve GI and mental symptoms in LC patients treated with budesonide and these changes may be mediated by the products of TRP metabolism.

High levels of fecal calprotectin and C-reactive protein in patients with colitis

Inflammatory bowel disease (IBD) with a poor prognosis may be due to persistent colitis. According to the latest guidelines, monitoring has become a part of the treatment process for colitis. Adequate monitoring of the patient's condition is necessary to determine the course of the disease to prevent the worsening of the condition and suppress the subclinical inflammatory process. This analytical study with a cross-sectional design was conducted to evaluate the activity of colitis using the results of C-reactive protein (CRP) and fecal calprotectin (FC) assays. FC levels were analyzed by ELISA, while CRP levels were analyzed using Siemens Flex particle-enhanced turbidimetric immunoassay. In 30 subjects with endoscopy and biopsy of colitis, 16 men and 14 women had a median age of 52.5 (18-70) years. The median FC value increased by 67 (7.3-722 g/g) and was positive (≥50 g/g) in 20 subjects (66.7%), and the mean CRP value was 13.64 mg/L, positive (10-15 mg/L) in 13 subjects (43.33%), and negative (<10 mg/L) in 17 subjects (56.67%). This study demonstrated that FC had a significant relationship with CRP (r=0.57; p<0.001) in patients with colitis. Assessing the levels of FC and CRP among patients with colitis can be useful to assess the worsening of symptoms early and reduce mortality and morbidity.

The Process of Developing a Disease Activity Index in Microscopic Colitis

BACKGROUND AND AIMS

Patient-reported outcome measures [PROMs] aim to measure patients' perception of how their disorder influences everyday functioning. The objective of this study was to develop a PROM to assess disease activity in microscopic colitis [MC] fulfilling the requirements of the Food and Drug Administration [FDA].

METHODS

The European Microscopic Colitis Activity Index [E-MCAI] was developed in four steps. [1] A list of symptoms associated with active MC was created by a group of experts in the field. [2] Content validity of the symptoms was performed by experts [n = 14] and patients [n = 79] using the Content Validity Index. [3] Questions and response alternatives were created for each symptom, and validity of the E-MCAI was evaluated with cognitive interviews with patients [n = 7] and by the experts. [4] A pilot postal survey was performed to ensure usability.

RESULTS

Seven of the symptoms related to active MC fulfilled the criteria for content validity and were included in the E-MCAI: stool consistency, stool frequency, stools at night, feel a need to pass more stools shortly after a bowel movement, urgent need to empty the bowel, leakage of stool and abdominal pain. The development and validation process resulted in the current version of the E-MCAI consisting of six questions related to MC.

CONCLUSIONS

The E-MCAI was developed using the methods advocated by the FDA. The evaluation indicates good content validity. Further evaluation will be performed to achieve construct validity, reliability and responsiveness in future cross-sectional and longitudinal studies.

NF-kB pathway is involved in microscopic colitis pathogenesis

OBJECTIVE

To investigate the potential inflammatory pathways involved in the development of microscopic colitis (MC).

METHODS

This prospective study analysed human intestinal tissue that was collected and classified as healthy controls (HC), microscopic colitis (MC) and ulcerative colitis (UC). An RT² Profiler PCR Array for human inflammatory response and autoimmunity was used to evaluate the expression of 84 specific genes related to the inflammatory and autoimmunity pathways. Data were validated by means of real-time polymerase chain reaction on an independent group of MC intestinal tissue samples.

RESULTS

This study measured the expression of inflammatory genes in HC (n = 10), in patients with MC (n = 8) and in patients with active UC (n = 10). Of the 84 genes included in the array, the expression of the C-C motif chemokine ligand 19, C-C motif chemokine ligand 21, lymphotoxin beta and complement C3 genes that are involved in the non-canonical nuclear transcription factor kappa B (NF-kB) pathway was increased by 2.96, 6.05, 5.96 and 5.93 times in MC compared with HC, respectively. These results were confirmed by real-time polymerase chain reaction.

CONCLUSIONS

The findings suggest that an impairment of the non-canonical NF-kB pathway is involved in the development of MC.

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.

Mucosal and faecal neutrophil gelatinase-associated lipocalin as potential biomarkers for collagenous colitis

BACKGROUND

Collagenous colitis (CC) is an inflammatory bowel disease where chronic diarrhoea is the main symptom. Diagnostic markers distinguishing between CC and other causes of chronic diarrhoea remain elusive. This study explores neutrophil gelatinase-associated lipocalin (NGAL) and its mRNA lipocalin2 (LCN2) as histological and faecal disease markers in CC.

METHODS

NGAL/LCN2 were studied in colonic biopsies from CC patients before and during budesonide treatment using RNA sequencing (n = 9/group), in situ hybridization (ISH) (n = 13-22/group) and immunohistochemistry (IHC) (n = 14-25/group). Faecal samples from CC (n = 3-28/group), irritable bowel syndrome diarrhoea (IBS-D) (n = 14) and healthy controls (HC) (n = 15) were assayed for NGAL and calprotectin.

RESULTS

NGAL/LCN2 protein and mRNA expression were upregulated in active CC vs HC, and vs paired samples of treated CC in clinical remission. IHC and ISH localized increased NGAL/LCN2 mainly to epithelium of active CC, compared to almost absence in HC and treated CC. In contrast, calprotectin was solely expressed in immune cells. Despite great individual differences, faecal NGAL was significantly increased in active CC compared to HC, IBS-D and treated CC and had high test sensitivity. Faecal calprotectin levels were variably increased in active CC, but the values remained below usual clinical cut-offs.

CONCLUSION

NGAL/LCN2 is upregulated in the epithelium of active CC and reduced during budesonide-induced clinical remission to the level of HC and IBD-S. This was reflected in NGAL faecal concentrations. We propose NGAL as an IHC marker for disease activity in CC and a potential faecal biomarker discriminating CC from HC and IBS-D.

Histological disease activity in patients with microscopic colitis is not related to clinical disease activity or long-term prognosis

BACKGROUND

Microscopic colitis (MC) is a common cause of chronic watery diarrhea. Biopsies with characteristic histological features are crucial for establishing the diagnosis. The two main subtypes are collagenous colitis (CC) and lymphocytic colitis (LC) but incomplete forms exist. The disease course remains unpredictable varying from spontaneous remission to a relapsing course.

AIM

To identify possible histological predictors of course of disease.

METHODS

Sixty patients from the European prospective MC registry (PRO-MC Collaboration) were included. Digitised histological slides stained with CD3 and Van Gieson were available for all patients. Total cell density and proportion of CD3 positive lymphocytes in lamina propria and surface epithelium were estimated by automated image analysis, and measurement of the subepithelial collagenous band was performed. Histopathological features were correlated to the number of daily stools and daily watery stools at time of endoscopy and at baseline as well as the clinical disease course (quiescent, achieved remission after treatment, relapsing or chronic active) at 1-year follow-up.

RESULTS

Neither total cell density in lamina propria, proportion of CD3 positive lymphocytes in lamina propria or surface epithelium, or thickness of collagenous band showed significant correlation to the number of daily stools or daily watery stools at any point of time. None of the assessed histological parameters at initial diagnosis were able to predict clinical disease course at 1-year follow-up.

CONCLUSIONS

Our data indicate that the evaluated histological parameters were neither markers of disease activity at the time of diagnosis nor predictors of disease course.

Serotonin in the Pathogenesis of Lymphocytic Colitis

Lymphocytic colitis (LC) is a chronic inflammatory disease associated with watery diarrhea, abdominal pain, and colonic intraepithelial lymphocytosis. Serotonin (5-hydroxytryptamine, 5-HT) is reported to increase in certain colon diseases; however, little is known regarding its metabolism in LC. In the present work, the level of 5-HT in serum and the number of enteroendocrine cells (EECs) as well as the expression of the 5-HT rate-limiting enzyme tryptophan hydroxylase 1 (TPH1) in colonic biopsies and urine 5-hydroxyindoeoacetic acid (5-HIAA) were determined in 36 LC patients that were treated with budesonide and 32 healthy controls. The 5-HT serum and 5-HIAA urine levels were measured using ELISA, the EEC number was determined immunohistochemically, and the colonic TPH1 mRNA expression was determined using RT-PCR. The levels of 5-HT and 5-HIAA and the number of EECs were higher in LC patients than in the controls, and positive correlations were observed between the 5-HT and 5-HIAA levels, 5-HT and EEC number, TPH1 mRNA and EEC number, as well as the severity of disease symptoms and 5-HIAA. Budesonide decreased the levels of 5-HT, 5-HIAA, and TPH1 expression and the number of EECs to values that did not differ from those for controls. In conclusion, the serotonin metabolism may be important for LC pathogenesis, and the urinary level of 5-HIAA may be considered as a non-invasive marker of this disease activity.

Overview of microscopic colitis

Microscopic colitis encompasses both collagenous and lymphocytic colitis and is a relatively common condition with rising incidence. Diagnosis is by colonoscopy (which is usually normal but may show some mild changes) and biopsies which reveal characteristic histological findings. Symptoms include non-bloody diarrhoea with urgency which may be associated with faecal incontinence and abdominal pain. Microscopic colitis is associated with a reduced health-related quality of life, and treatment is aimed at symptom control. Medications linked with the development of microscopic colitis, including proton pump inhibitors, non-steroidal anti-inflammatory drugs and selective serotonin-reuptake inhibitors, should be discontinued. If symptoms persist, budesonide is a licensed treatment for microscopic colitis which has been shown to be effective in clinical trials and real-world practice.

All-cause and cause-specific mortality in microscopic colitis: a Danish nationwide matched cohort study

BACKGROUND

The long-term natural history of microscopic colitis remains uncertain.

AIM

To describe the mortality in a large unselected cohort of patients with microscopic colitis.

METHODS

All Danish patients above 18 years with an incident diagnosis of microscopic colitis from 2001 to 2018 were identified from nationwide registries and compared to age- and sex-matched controls (variable 1:10 ratio). Patients were categorised according to subtypes: lymphocytic colitis and collagenous colitis. The relative risk of death by any cause was analysed with Cox regression models estimating both crude and comorbidity-adjusted hazard ratios (HRs) with 95% confidence intervals (CIs). Cause-specific death was evaluated with cumulative incidence functions. An E-value was calculated to address the impact of unmeasured confounding.

RESULTS

The final cohort consisted of 14 024 patients with microscopic colitis. The mean follow-up was 5.8 (standard deviation SD, 2.9) years and the mean age at diagnosis was 61.1 (SD 13.9) years, 70% were women and 41% were diagnosed with lymphocytic colitis. The main results showed a 25% increased risk of all-cause death in patients with microscopic colitis; however, the relative risk was attenuated to 9% when adjusting for comorbidities (95% CI, 1.05-1.14). The E-value indicates that unmeasured confounding could explain the residual observed increased all-cause mortality. Mortality was significantly increased in patients with both lymphocytic colitis (HR 1.15; 95% CI, 1.08-1.23) and collagenous colitis (HR 1.06; 95% CI, 1.01-1.12) in fully adjusted analyses. The absolute difference in death between patients with microscopic colitis and matches was 0.9% at 1 year, 2.8% at 5 years, 5.0% at 10 years and 3.0% at 15 years. Cumulative incidence functions showed that patients with microscopic colitis were more likely to die due to smoking-related diseases including ischemic heart and lung diseases, but had a significant decreased risk of death due to colorectal cancers (P < 0.0001).

CONCLUSION

In an unselected large nationwide cohort of patients with microscopic colitis, the risk of death was significantly increased compared to the background population. However, the increased mortality seemed to be associated to a high burden of comorbidities and unmeasured life-style factors including smoking and not microscopic colitis per se.

Microscopic colitis: pathophysiology and clinical management

Microscopic colitis is a chronic inflammatory disease of the colon that frequently causes chronic watery diarrhoea that might be accompanied by abdominal pain, nocturnal diarrhoea, urgency, and faecal incontinence. These symptoms lead to poor quality of life and increased health-care costs. Diagnosis relies on histological examination of multiple biopsy samples from the colonic mucosa, which often show no or only few abnormalities on endoscopy. Two major histological subtypes can be distinguished-collagenous colitis and lymphocytic colitis-but incomplete and variant forms with fewer characteristic features have been reported. Here we summarise the latest evidence on epidemiology, pathogenesis, and risk factors, and discuss established and novel therapeutic options for clinical remission. Finally, we propose an updated treatment algorithm. Further prospective studies are needed to clarify the natural history of microscopic colitis, supported by validated criteria for the assessment of disease activity.

Faecal Calprotectin and 7-α Cholestenone Levels in Microscopic Colitis: Experience from Edinburgh

Introduction

Microscopic colitis (MC) is an important cause of chronic, watery diarrhoea. Currently, there is no specific biomarker available to guide diagnosis. The use of faecal calprotectin (FCP) as a potential marker has been addressed in only a few studies. Further, bile acid malabsorption (BAM) often accompanies MC. Current practice recommends the selenium-labelled homocholic acid-taurine (SeHCAT) test, but at our centre, 7 alpha-hydroxy-4-cholesten-3-one (7αC) is used as a simpler and less expensive alternative to SeHCAT, with values over 22ng/mL indicating BAM. This study aims to evaluate the use of FCP as a biomarker in the diagnosis of MC and the role of 7αC in detecting concomitant BAM with MC.

Methods

Pathology records were retrospectively reviewed for patients diagnosed with collagenous colitis (CC) between 2000 and 2018 and lymphocytic colitis (LC) between 1995 and 2011. FCP and 7αc results, if measured within 6 months of pathological diagnosis, were extracted for analysis.

Results

Between 2000 and 2018, 646 CC cases were confirmed on histology. Of 646 patients, 147 had FCP measured; in 111 (75.5%) FCP was elevated with mean levels 238.1μg/g (SD±273.0); 140/646 had 7αC measured; 16 (11.4%) indicated BAM. Mean levels were 10.2ng/mL (SD±9.4). During a 21-year period (1995–2011), 204 LC diagnoses were made: 14/204 had FCP measured; 8 (57.1%) were elevated. Mean levels were 128.4μg/g (SD±107.7). Of 204 LC patients, 20 had 7αC measured, 5 (25%) indicating BAM. Mean levels were 13.95ng/mL (SD±9.4).

Discussion

Both CC and LC were associated with raised FCP during the diagnostic phase, supporting the potential role of its use in clinical practice. Furthermore, we present results of using 7αC in identifying BAM amongst patients with MC. In our cohort, low levels of 7αC suggest relatively low concordance of BAM with MC.

Undiagnosed microscopic colitis: a hidden cause of chronic diarrhoea and a frequently missed treatment opportunity

Microscopic colitis (MC) is a treatable cause of chronic, non-bloody, watery diarrhoea, but physicians (particularly in primary care) are less familiar with MC than with other causes of chronic diarrhoea. The colon in patients with MC is usually macroscopically normal. MC can only be diagnosed by histological examination of colonic biopsies (subepithelial collagen band >10 µm (collagenous colitis) or >20 intraepithelial lymphocytes per 100 epithelial cells (lymphocytic colitis), both with lamina propria inflammation). The UK National Health Service exerts downward pressure to minimise colonoscopy referrals. Furthermore, biopsies are often not taken according to guidelines. These factors work against MC diagnosis. In this review, we note the high incidence of MC (comparable to ulcerative colitis and Crohn's disease) and its symptomatic overlap with irritable bowel syndrome. We also highlight problems with the recommendation by National Health Service/National Institute for Health and Care Excellence guidelines for inflammatory bowel diseases that colonoscopy referrals should be based on a faecal calprotectin level of ≥100 µg/g. Faecal calprotectin is <100 µg/g in over half of individuals with active MC, building into the system a propensity to misdiagnose MC as irritable bowel syndrome. This raises important questions-how many patients with MC have already been misdiagnosed, and how do we address this silent burden? Clarity is needed around pathways for MC management; MC is poorly acknowledged by the UK healthcare system and it is unlikely that best practices are being followed adequately. There is an opportunity to identify and treat patients with MC more effectively.

Budesonide treatment for microscopic colitis: systematic review and meta-analysis

Microscopic colitis (MC), encompassing lymphocytic and collagenous colitis, is a common cause for chronic nonbloody diarrhoea, which impacts significantly on the quality of life for patients. Despite increasing awareness of the condition and its treatment, there is considerable variation in therapeutic approaches. To conduct a systematic review and meta-analysis on the efficacy and safety of budesonide in the treatment of MC. We searched Medline, Embase and Central databases using predefined search methodology for randomised trials using budesonide in the treatment of MC. We extracted data, on the efficacy and safety of budesonide, from studies identified that met the feasibility for analysis criteria. These data were pooled with a fixed effects model. Nine studies met the inclusion criteria for analysis. The pooled odds ratios (ORs) for a response to budesonide therapy at induction and maintenance were 7.34 [95% confidence interval (CI): 4.08-13.19] and 8.35 (95% CI: 4.14-16.85) respectively. Histological response rates were superior in budesonide-treated patients compared to placebo following induction (OR: 11.52; 95% CI: 5.67-23.40) and maintenance treatment (OR: 5.88; 95% CI: 1.90-18.17). There was no difference in adverse events. Significant relapse rates (>50%) were observed following treatment cessation with no difference noted between the budesonide or the placebo-treated patients. Budesonide is an effective treatment option for MC for achieving induction and maintenance of both clinical and histological response. High relapse rates on treatment cessation were observed.

Evaluation of Melatonin Secretion and Metabolism Exponents in Patients with Ulcerative and Lymphocytic Colitis

Inflammatory bowel diseases, particularly ulcerative colitis (UC) and lymphocytic colitis (LC), affect many people. The role of melatonin in the pathogenesis of UC is precisely determined, whereas in LC it remains unknown. The aim of this study was to compare the expression of the melatonin-synthesizing enzymes tryptophan hydroxylase (TPH1), arylalkylamine-N-acetyltransferase (AANAT), and N-acetylserotonin methyltransferase (ASMT) in the colonic mucosa and urinary excretion of 6-sulfatoxymelatonin in patients with ulcerative and lymphocytic colitis. The study included 30 healthy subjects (group C), 30 patients with severe ulcerative colitis (group UC), and 30 patients with lymphocytic colitis (group LC). The diagnosis was based on endoscopic, histological, and laboratory examinations. Biopsy specimens were collected from right, transverse, and left parts of the colon. The levels of mRNA expression, TPH1, AANAT, and ASMT were estimated in the colonic mucosa with RT-PCR. The urine concentration of aMT6s was determined by the photometric method. The expression of TPH1, AANAT, and ASMT in colonic mucosa in UC and LC patients was significantly higher than in healthy subjects. Significant differences were found in the urinary aMT6s excretion: group C—13.4 ± 4.8 µg/24 h, group UC—7.8 ± 2.6 µg/24 h (p < 0.01), group LC—19.2 ± 6.1 µg/24 h (p < 0.01). Moreover, a negative correlation was found between fecal calprotectin and MT6s—in patients with UC − r = −0.888 and with LC − r = −0.658. These results indicate that patients with UC and those with LC may display high levels of melatonin-synthesizing enzymes in their colonic mucosa, which could possibly be related to increased melatonin synthesis as an adaptive antioxidant activity.

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.

Endoscopic findings and colonic perforation in microscopic colitis: A systematic review

INTRODUCTION

Microscopic colitis (MC) is a clinical syndrome of severe watery diarrhea with few or no endoscopic abnormalities. The incidence of MC is reported similar to that of other inflammatory bowel diseases. The need for histological confirmation of MC frequently guides reimbursement health policies. With the advent of high-definition (HD) coloscopes, the incidence of reporting distinct endoscopic findings in MC has risen. This has the potential to improve timely diagnosis and cost-effective MC management and diminish the workload and costs of busy modern endoscopy units.

METHODS

Publications on distinct endoscopic findings in MC available until March 31st, 2017 were searched systematically (electronic and manual) in PubMed database. The following search terms/descriptors were used: collagenous colitis (CC) OR lymphocytic colitis (LC) AND endoscopy, colonoscopy, findings, macroscopic, erythema, mucosa, vasculature, scars, lacerations, fractures. An additional search for MC AND perforation was made.

RESULTS

Eighty (n=80) articles, predominantly single case reports (n=49), were found. Overall, 1582 (1159F; 61.6±14.1 years) patients (pts) with MC and endoscopic findings were reported. The majority of articles (n=62) were on CC (pts 756; 77.5% females). We identified 16 papers comprising 779 pts (69.2% females) with LC and 7 articles describing 47 pts (72.3% females) diagnosed as MC. The youngest patient was 10 and the oldest a 97-year-old. Aside diarrhea, symptoms included abdominal pain, weight loss, bloating, flatulence, edema and others. In the study group we found 615 (38.8%) persons with macroscopic lesions in gut. Isolated linear ulcerations were identified in 7 pts (1.1%) while non-ulcerous lesions i.e. pseudomembranes, a variable degree of vasculature pruning & dwindling, mucosal lacerations and abnormalities such as erythema/edema/nodularity, or surface textural alteration in 608 pts (98.1%). The location of endoscopic findings was not reported in 27 articles. The distinct endoscopic findings were described in the left (descending, sigmoid, rectum - 10/21/11 studies), right (cecum, ascending - 7/7 studies), transverse colon (n=12), as well as duodenum (n=4), and terminal ileum (n=2). In 17 (1.1%) pts colonic perforation occurred.

CONCLUSION

Endoscopic findings are recognized with increased frequency in pts with MC. This could improve MC diagnosis by prompting a more extensive biopsy protocol in such cases and an earlier initiation of treatment. Procedure-related perforation has been reported in this group; therefore, cautious air insufflation is advisable when endoscopic findings are recognised.