Gut integrity, systemic inflammation and exacerbations of COPD: the role of I-FABP.

High plasma intestinal-fatty acid binding protein (I-FABP) levels reflect gut epithelial integrity loss. Its interplay with systemic inflammation remains poorly understood in COPD and exacerbations of this disease (ECOPD). Therefore, the aim of this study was to investigate the association between plasma I-FABP levels, inflammatory markers and severity of COPD (including severity and frequency of ECOPD), and to evaluate I-FABP as potential clinical marker. Data from the 2-year observational ICE-AGE study were analysed post hoc. Plasma I-FABP levels, and inflammatory parameters (e.g. IL-6, IL-8, monocytes, granulocytes and TNF-alpha) were assessed in patients with COPD and controls. Historic ECOPD frequency and severity were recorded at inclusion and monitored prospectively (2-year follow-up). Group comparisons were performed using the Mann-Whitney U and Kruskal-Wallis tests. Associations between variables were evaluated using Spearman rho. 205 patients with COPD (62 (57-67) years; 58% males; 50% (36-62%) FEV1 predicted) and 200 non-COPD controls (61 (57-64) years, 45% males) were included. The majority had ≥1 ECOPD in the previous year (77.3%) and during 2-year follow-up (86.3%). Plasma I-FABP levels were higher in patients with COPD vs non-COPD (1116.8 (840.4-1735.9) pg/mL vs 950.2 (707.4-1482.2) pg/mL, p = 0.003). In patients with COPD, plasma I-FABP was positively associated with IL-8 (r = 0.204, p = 0.004) and TNF-alpha (r = 0.181, p = 0.017). Plasma I-FABP was not associated with ECOPD frequency and severity before or after inclusion. Plasma I-FABP levels were higher and associated with systemic inflammation in COPD but not associated with ECOPD. This supports that plasma I-FABP levels may be involved in the gut-lung cross-talk in patients with COPD.