Monocyte chemotactic protein-1 and nitrotyrosine in irritable bowel syndrome.

Irritable bowel syndrome (IBS) is one the most frequent and common functional gastrointestinal disorders that has a multifactorial etiopathogenesis. Multiple biomarkers have been tested in search for a reliable and specific biomarker, but there is not yet a specific biomarker for IBS. The aim of this study was to evaluate two biomarkers of different putative pathways of the pathogenesis of IBS: the monocyte chemotactic protein-1 (MCP-1) and nitrotyrosine, in order to establish their role as potential biomarkers. We enrolled 42 consecutive IBS patients diagnosed by Rome III criteria and 35 consecutive healthy controls. Serum concentrations for the two biomarkers (MCP-1 and nitrotyrosine) were determined using commercial ELISA kits. Serum levels of MCP-1 were not statistically significantly higher in IBS patients than in controls (204±130 vs. 174±73 pg/ml; P=0.311). Nitrotyrosine levels were statistically significantly lower in IBS patients than in controls (30±12 vs. 353±14 nM; P=0.050). MCP-1 levels were higher in IBS patients with metabolic syndrome versus IBS patients without metabolic syndrome (239±153 vs. 168±120 pg/ml; P=0.948) and in controls with metabolic syndrome (174±56 pg/ml). MCP-1 serum levels were statistically significantly higher in IBS patients with metabolic syndrome than in controls (239±153 vs. 157±89 pg/ml; P=0.037), suggesting multiple factors being involved, particularly the diet and its relation with the metabolic syndrome, and it suggests that MCP-1 could be a marker of subclinical atherosclerosis. Low-grade inflammation might be related to oxidative stress, which plays an underestimated role in the pathogenesis of IBS.