Faecal short-chain fatty acids - a diagnostic biomarker for irritable bowel syndrome?

Abstract

BackgroundThe diagnosis of irritable bowel syndrome (IBS) relies on symptom-based criteria. A valid and reliable biomarker that could confirm the diagnosis is desirable. This study evaluated the properties of faecal short-chain fatty acids (SCFA) as diagnostic biomarkers for IBS.MethodsTwenty-five subjects with IBS and 25 controls were included in this explanatory case–control study. Stool samples were analysed for SCFA (acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, and isovaleric acid) with gas chromatography and reported as mmol/l and molar%. In the search for the best way to distinguish between subjects with and without IBS, the total amount and the amount of each of the SCFA were measured, and the proportions and differences between the SCFA were calculated.ResultsIn the IBS and control group, the mean age was 46.2 (SD 12.9) and 49.2 (SD 14.6), and the number of females was 13/25 (52 %) and 15/25 (60 %) respectively. The difference between propionic and butyric acid (mmol/l) had the best diagnostic properties, the area under the Receiver Operating Characteristic curve was 0.89 (95 % CI: 0.80–0.98) (p < 0.001). With a cut-off value > 0.015 mmol/l indicating IBS, the sensitivity, specificity, positive and negative likelihood ratio, and diagnostic odds ratio were 92 %, 72 %, 3.29, 0.11 and 29.6 respectively. Similar diagnostic properties were shown for all the IBS subgroups.ConclusionsThe study indicated that faecal SCFA could be a non-invasive, valid and reliable biomarker for the differentiation of healthy subjects from subjects with IBS.

Enterochromaffin Cells Are Gut Chemosensors that Couple to Sensory Neural Pathways

“…Here we identify one such metabolite, isovalerate, as a potent EC cell stimulus that modulates sensory neurons via EC cell-neural signaling. Although isovalerate accounts for only a minor percentage of total fatty acid metabolites, high levels are toxic and associated with visceral pain and other gastrointestinal disorders, such as post-infectious irritable bowel syndrome (Brierley and Linden, 2014; Farup et al, 2016; Tanaka et al, 1966). EC cells may act as sensors for such potentially harmful dysbiosis.…”

Beneficial effect of butyrate‐producing Lachnospiraceae on stress‐induced visceral hypersensitivity in rats

“…SCFAs are metabolites fermented by specific anaerobic bacteria from non‐digestible dietary fiber and resistant starches, and they have extensive regulatory functions in the interaction between microbes and hosts . A few studies have shown that SCFAs are associated with IBS; however, whether they are beneficial or harmful remains controversial …”

“…11 A few studies have shown that SCFAs are associated with IBS; however, whether they are beneficial or harmful remains controversial. 12,13 In this study, to further investigate the possible role of gut microbiota in stress-induced visceral hypersensitivity, we examined the influence of chronic water avoidance stress (WAS) in rats on the intestinal barrier and bacterial community and function. We also identified stress-associated microbial species and further verified the beneficial effect of Roseburia, a butyrateproducing genus that was significantly reduced in WAS rats, on stress-induced visceral hypersensitivity.…”

Fecal Clostridiales distribution and short‐chain fatty acids reflect bowel habits in irritable bowel syndrome

“…(Taverniti and Guglielmetti, 2014;Rajilic-Stojanovic et al, 2015). In addition, the available scientific literature also describes the significant role played by altered levels of short-chain fatty acids (SCFAs) in IBS (Ringel-Kulka et al, 2015;Camilleri et al, 2016;Farup et al, 2016). For instance, Farup and colleagues proposed that propionate and butyrate may act as discriminatory factors to differentiate healthy subjects from subjects with IBS (Ringel-Kulka et al, 2015).…”