Decrease of Plasma Soluble (Pro)renin Receptor by Bariatric Surgery in Patients with Obstructive Sleep Apnea and Morbid Obesity

Background: Plasma concentrations of soluble (pro)renin receptor [s(P)RR], which are elevated in patients with obstructive sleep apnea (OSA), have not been studied in morbid obesity. The aim of this study is to clarify effects of bariatric surgery on plasma s(P)RR concentrations and identify associated factors for their changes in OSA patients with morbid obesity. Methods: Twenty-three patients with OSA complicated by morbid obesity (10 men and 13 women; body mass index, 40.76.16kg/m(2)) without chronic kidney disease were followed up after bariatric surgery. Overnight polysomnography (PSG) was performed before surgery, and 4 and 24 weeks after surgery. Plasma s(P)RR concentrations were measured each morning after PSG. Results: Preoperative plasma s(P)RR concentrations showed significant positive correlations with serum creatinine (P<0.05), arousal index (P<0.01), apnea-hypopnea index (AHI) (P<0.05), apnea index (P<0.005), and desaturation index (P<0.05), and a significant inverse correlation with an estimated glomerular filtration rate (P<0.05). With the improvement of these PSG parameters, plasma s(P)RR concentrations significantly decreased from 15.3 +/- 3.6 to 12.5 +/- 2.7ng/mL 4 weeks after surgery, which further decreased to 11.4 +/- 2.4ng/mL 24 weeks after surgery. The association observed before surgery between plasma s(P)RR concentrations and the PSG parameters was not seen after surgery. Conclusions: Bariatric surgery in patients with OSA complicated by morbid obesity decreased plasma s(P)RR concentrations. The most associated factors for their changes were arousal index, AHI, apnea index, and desaturation index.