The utility of biomarkers in inflammatory bowel disease, with a focus on fecal calprotectin

Petryszyn P, et al. Faecal calprotectin as a diagnostic marker of inflammatory bowel disease in patients with gastrointestinal symptoms: meta-analysis. Eur J Gastroenterol Hepatol. 2019 Nov;31(11):1306-1312.

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“The study aimed to assess efficacy of faecal calprotectin as a diagnostic marker of IBD in patients with symptoms suggestive of such diagnosis. Inclusion criteria comprised experimental and observational studies, adults with gastrointestinal symptoms, calprotectin as index and colonoscopy as reference test, presence of data on/enabling the calculation of diagnostic accuracy parameters. For each study, sensitivity and specificity of faecal calprotectin were analysed as bivariate data. Nineteen studies were identified. The total number of patients was 5032. Calculated pooled sensitivity and specificity were 0.882 [95% confidence interval (CI), 0.827-0.921] and 0.799 (95% CI, 0.693-0.875), respectively. Following faecal calprotectin incorporation in the diagnostic work-up of 100 people with suspected IBD, 18 non-IBD patients will have a colonoscopy performed and one patient with the disease will not be referred for this examination. Faecal calprotectin concentration measurement is a useful screening test to rule out IBD, at the same time reducing the need for colonoscopy by 66.7%.”

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Pathogenesis of diversion colitis

This week’s discussions included the causes of diversion colitis.

Tominaga K, et al. Diversion colitis and pouchitis: A mini-review. World J Gastroenterol. 2018 Apr 28;24(16):1734-1747.

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“The basic mechanisms underlying diversion colitis are still unclear. Glotzer hypothesized that it might be the result of bacterial overgrowth, the presence of harmful bacteria, nutritional deficiencies, toxins, or disturbance in the symbiotic relationship between luminal bacteria and the mucosal layer[2]. Reportedly, concentrations of carbohydrate-fermenting anaerobic bacteria and pathogenic bacteria are reduced in de-functioned colons[5,23,53] and these reports indicate that the overgrowth of anaerobic bacteria or a pathogenic bacterium is unlikely to be an important etiological factor. On the other hand, there is an increase of nitrate-reducing bacteria in patients with diversion colitis[7] and nitrate-reducing bacteria produce nitric oxide (NO) which plays a protective role in low concentrations, but at higher levels it becomes toxic to the colonic tissue[54]. Thus, it has been suggested that increases in nitrate-reducing bacteria may result in toxic levels of NO, leading to the diversion colitis.” (Tominaga, 2018, p. 1739)

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