P179 Decrease in Butyric Acid in fecal matter in patients with Inflammatory Bowel Disease is associated with the levels of secretory Immunoglobulin A and fecal calprotectin

Abstract

Abstract Background Accumulating evidence shows that the development of IBD is always accompanied by dysbiosis of the intestinal microbiota. Short-chain fatty acids (SCFAs) are produced by prebiotic intestinal bacteria, with mportant anti-inflammatory functions, delaying the clinical progression of IBD. The aim of this study is to compare SCFA levels in fecal matter in patients with IBD versus patients with Spondyloarthritis (SpA) and healthy controls. Methods 24 patients were evaluated for the presence of gastrointestinal symptoms, demographic data and inflammatory markers: fecal calprotectin, C-reactive protein (CRP), secretory IgA (SIgA) and erythrocyte sedimentation rate (ESR). The quantification of SCFAs (acetic-AC, propionic-AP, butyric-AB and total SCFAs-ACCC-T) from fecal matter was analyzed by ultra-high pressure liquid chromatography coupled to mass spectrometry (UHPLC-Q/ TOFMS). Results 33.3% of patients with IBD were men, with body mass index >25 in 16.7%; 83.3% presented more than 2 gastrointestinal symptoms at the time of sample collection, 33.3% had high levels of fecal calprotectin, 50% had CRP levels higher than 3mg/L and high ESR in 33.3% and a mean SIgA. of 27.73±5.03 g/mL. Very decreased levels of butyric acid (BA)ug/mL and T-SCFA were observed in IBD (9.45±4.89 and 121.73±65.94, respectively), compared to CS (BA 20.84±8.83 and total SCFA.12±122.09)., SpA SG (AB 13.35±10.44 and total AGCC 150.73±128.52) and SpA without OS (AB 21.13±5.68 and AGCC-T 219.51±229.65). Significant differences were found in fecal BA levels between the study groups (p=0.027). Interestingly, this metabolite in the CS group and the SpA group without OS did not show differences between them, but compared to the IBD group p=0.015 and 0.009 respectively, with a decrease in IBD. And interestingly, no differences were evident between fecal SCFA levels between the IBD group and the SpA group with OS even without a diagnosis of IBD. A principal component analysis was performed for the IBD group where two components were identified that group where COMP.1 was defined by a high correlation between the levels of each of the ACCC (AB CCF= 0.994, AA CCF= 0.935, AP= 0.610 and AGCC-TCCF= 0.910) that had an inverse relationship with COMP.2 which was made up of SIgA (CCF=0.988) and fecal calprotectin (CCF= 0.988). Conclusion SCFAs play a key role in maintaining immune homeostasis both locally and systemically. BA levels were significantly lower in patients with IBD compared to CS and those with SpA. This evidence clearly supports the hypothesis that relates the lack of BA with an exacerbated inflammatory response that could give rise to a dysfunctional intestinal epithelial barrier by regulating the production of mucosal antibodies such as SIgA.