Anti-sRAGE autoimmunity in obesity: downturn after bariatric surgery is independent of previous diabetic status.

Aim: Morbid obesity increases the risk of cardiovascular disease (CVD). The receptor for advanced glycation end-products (RAGE) is implicated in proinflammatory processes that underlie CVD. Its soluble form (sRAGE) has been proposed as a vascular biomarker. Recently, anti-sRAGE autoantibodies were described and found to be increased in diseases where RAGE is overexpressed. This study aimed to investigate serum levels of anti-sRAGE autoantibodies in morbidly obese patients.

Methods: After exclusion based on specific criteria, 150 subjects (50 normoglycemics, 50 glucose-intolerants and 50 diabetics) were randomly recruited from a cohort of 750 obese patients (ABOS). Serum sRAGE and anti-sRAGE autoantibodies were measured before bariatric surgery. Sixty-nine patients were followed for up to 1year after gastric bypass, and their levels of sRAGE and anti-sRAGE autoantibodies measured. The control group consisted of healthy blood donors.

Results: Compared with controls, baseline levels of sRAGE and anti-sRAGE autoantibodies were significantly higher in all obese patients independently of glucose regulation (P<0.001). At 1year after gastric bypass, sRAGE and anti-sRAGE were decreased (P<0.001). The decrease in anti-sRAGE autoantibodies was correlated with an increase in high-density lipoprotein (HDL; P=0.02).

Conclusion: Independently of previous diabetic status, morbid obesity increases sRAGE and anti-sRAGE levels. Weight loss after gastric bypass is followed by a decrease in both titres. The decrease in anti-sRAGE correlates with an increase in HDL.