Increased Serum Apelin Levels in Patients with Inflammatory Bowel Disease

Apelin has been implicated in the pathogenesis of several chronic inflammatory diseases through mechanisms related to endothelial cells dysfunction. There is evidence of increased apelin levels in mesenteric adipose tissue and colonic epithelium in patients with inflammatory bowel disease (IBD), but their significance remains unclear. We aimed to measure serum apelin (SA) levels in patients with IBD and to evaluate an association with disease characteristics. SA levels of 104 IBD patients and age and sex matched healthy controls (HCs) in a 1:1 ratio were compared. SA-13 levels were measured using an enzyme-linked immunosorbent assay (ELISA). Mean SA levels were increased in IBD patients compared to HCs (1996.29 ± 1592.96 pg/mL vs. 1552.99 ± 809.64 pg/mL, p = 0.012). Both patients without and with cardiovascular disease (CVD) had increased SA levels (2076.44 ± 1714.74 pg/mL vs. 1525.75 ± 818.74 pg/mL, p = 0.011 and 1743.01 ± 1116.26 pg/mL vs. 1283.92 ± 726.85 pg/mL, p = 0.035, respectively). An inverse association between mean SA levels and a history of musculoskeletal extraintestinal manifestations in the subgroup of IBD patients without CVD was found (p = 0.043). The present study—the first to evaluate SA levels in patients with IBD—showed that IBD patients have higher levels of SA compared to HCs. The potential role of SA in IBD merits further investigation in larger studies.