Systematic review with meta-analysis: diagnostic overlap of microscopic colitis and functional bowel disorders.

BACKGROUND: Microscopic colitis shares certain common clinical manifestations with functional bowel disorders, especially diarrhoea-dominant irritable bowel syndrome (IBS) and functional diarrhoea. However, the exact relationship between microscopic colitis and functional bowel disorders has not been systematically assessed. AIM: To conduct a systematic review and meta-analysis on the diagnostic overlap between functional bowel disorders and microscopic colitis. METHODS: We searched MEDLINE, EMBASE and SCOPUS databases, as well as the abstract books of the major gastroenterology meetings, to investigate the prevalence of microscopic colitis among patients with functional bowel disorders (considering all subtypes of both disorders) and vice versa. Data were pooled with a random-effects model. RESULTS: Of 227 references identified, data were collected from 26 studies and a total of 5,099 adult patients. The pooled prevalence any type of functional bowel disorders in patients who present diagnostic criteria of microscopic colitis was 39.1% (95% CI: 22.8-56.6%; I2 : 97%) and was higher for lymphocytic colitis than for collagenous colitis (40.7% vs. 28.4%, respectively; P = 0.58). The prevalence of microscopic colitis in functional bowel disorders patients was 7% (95% CI: 3.6-11.4%), reaching 9.8% (95% CI: 4.4-17.1%; I2 : 95%) in patients exhibiting diarrhoea-dominant IBS, nonsignificantly higher than microscopic colitis rates among patients with constipation-dominant IBS (1.3%) or mixed-dominant IBS (1.9%). CONCLUSIONS: There is a significant overlap of symptoms between microscopic colitis and functional bowel disorders, especially in diarrhoeal subtypes. The high proportion of microscopic colitis among diarrhoea-dominant functional syndromes should serve as a call for more active diagnosis in selected patients.

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.

Advances in knowledge on microscopic colitis: From bench to bedside.

Microscopic colitis (MC) is a general term that describes a family of chronic inflammatory bowel diseases, including lymphocytic colitis (LC) and collagenous colitis (CC). The two forms are characterized by chronic watery diarrhea with normal or near normal endoscopic colonic appearance and specific histopathological abnormalities.Data from recent epidemiological studies reported the diagnosis of MC from several different regions in the world, providing that it can be a worldwide condition. The etiopathogenesis of MC still remains unknown but it is generally accepted that MC is a multifactorial disease, probably secondary to an abnormal immune reaction in predisposed individuals, triggered by different luminal factors (infections, drugs, autoimmunity and/or bile acids). Furthermore, some studies show that the epithelial barrier function in the colonic mucosa of MC patients is also impaired. Several mucosal factors of intestinal inflammation have been studied in MC, postulating that an aberrant T-lymphocyte response may lead to a chronic gut inflammatory condition, with the infiltration of colonic mucosa by different proportion of subset of T-lymphocytes. Little is known about the specific inflammatory mediators in MC pathogenesis, but a predominant Th1 type cytokine profile has been demonstrated. Currently, a number of medical treatments have been studied in MC patients, following mainly an empirical treatment approach. Further studies are needed in order to obtain prospective and more evidence-based data. In the future, it will be possible to develop causal treatment approaches after better understanding the molecular mechanisms behind the origin of the disease.

Sequential evaluation of thiopurine methyltransferase, inosine triphosphate pyrophosphatase, and HPRT1 genes polymorphisms to explain thiopurines' toxicity and efficacy.

AIM: To evaluate the polymorphisms of several genes involved in the azathioprine and mercaptopurine metabolism, in an attempt to explain their toxicity and efficacy in Crohn's disease and ulcerative colitis. METHODS: In 422 consecutive patients (250 with Crohn's disease and 172 with ulcerative colitis) and 245 healthy controls, single nucleotide polymorphisms of thiopurine methyltransferase, inosine triphosphate pyrophosphatase and hypoxanthine phosphoribosyl transferase (HPRT1) genes were related to the occurrence of adverse drug reactions (ADRs) and efficacy of therapy. RESULTS: Seventy-three patients reported 81 episodes of ADRs; 45 patients did not respond to therapy. Frequency of thiopurine methyltransferase risk haplotypes was significantly increased in patients with leucopenia (26% vs. 5.7% in patients without ADRs, and 4% of controls) (P < 0.001); no correlation with other ADRs and efficacy of therapy was found. Conversely, the frequency of inosine triphosphate pyrophosphatase and HPRT1 risk genotypes was not significantly different in patients with ADRs (included leucopenia). Non-responders had an increased frequency of inosine triphosphate pyrophosphatase risk genotypes (P = 0.03). CONCLUSIONS: The majority of azathioprine/mercaptopurine-induced ADRs and efficacy of therapy are not explained by the investigated gene polymorphisms. The combined evaluation of all three genes enhanced the correlation with leucopenia (43.5% vs. 23% in controls) (P = 0.008), at the expense of a reduced accuracy (60%).

Acute intestinal obstruction and NOD2/CARD15 mutations among Italian Crohn's disease patients.

UNLABELLED: Three CARD15 mutations (SNP8, SNP12, SNP13) were significantly associated with CD, however ethnic variations and genotype-phenotype relationships are still to be defined. AIMS: To evaluate the prevalence of three CARD15 mutations in 91 in-out consecutive CD, 109 Ulcerative Colitis (UC), 101 healthy controls; to examine the genotype-phenotype relationships among italian pts with CD. MATERIAL AND METHODS: The three mutations were determined by direct sequencing analysis. In CD were evaluated several feature of disease phenotype. Data analysis was performed by using c2 or Fisher Test applying Bonferroni's correction. RESULTS: The allelic and genotype frequencies of CARD15 mutations were significantly associated to CD. None of controls or UC were homozygotes (OM) or compound heterozigotes (CET). In CD the carriers of at least one mutation were 26/91 (28.6%). The frequencies of simple heterozygotes (ET), CET and OM were: 19/26, 4/26, 3/26 respectively. A significant positive association was found between small bowel location and an acute intestinal obstruction at diagnosis and the carriers of at least one mutation (p = 0.036, OR:0.33 [0.12-0.9] and p = 0.0025, OR:0.125 [0.03-0.5], respectively), particularly with OM and CET genotype (p = 0.005, OR:0.07 [0.01-0.6]). A positive trend between the number of surgery and the carriers of at least one mutation was found, but it didn't reach statistical significance (p = 0.0469, OR:0.3 [0.1-0.96]). No relationship between CARD15 mutations and the other phenotype characteristics was found. CONCLUSIONS: Our data confirms that CARD15 mutations are significantly associated with CD also in Italian population and with small bowel location (OM and CET genotype). A new positive association was also found between the carriers of at least one mutation and the acute intestinal obstruction at diagnosis.

Review article: biological agents in the treatment of Crohn's disease.

The main aim of the management of Crohn's disease is to reduce inflammation. Current approaches with corticosteroids, immunosuppressive agents, mesalazine and antibiotics have limited therapeutic benefit for many patients. Considerable progress has been made with regard to our knowledge of the basic mechanisms of the disease, which is associated with immunological imbalance characterized by an excess of pro-inflammatory cytokines. Recent advances in bio-technology have led to the development of many new therapeutic agents, so-called biological agents, which selectively target single key processes involved in the pathogenesis of the disease. A growing number of biological agents are under investigation in both randomized controlled trials and uncontrolled studies. The aim of this review is to provide the clinician with an insight into the randomized controlled trials published in the literature on the use of biological agents in the treatment of Crohn's disease.