Soluble (Pro)Renin Receptor Level in Patients with Severe Obesity Is Associated with Visceral Adiposity and Is Involved with Insulin Resistance and Renal Injury

Introduction: High soluble (pro)renin receptor (s[P]RR) level in circulation is reported in obese patients; however, it is unclear which body composition components are responsible for it. In this study, the authors examined blood s(P)RR levels and ATP6AP2 gene expression levels in visceral and subcutaneous adipose tissue (VAT, SAT) in severely obese patients who underwent laparoscopic sleeve gastrectomy (LSG), with the aim of clarifying the relationship with body composition and metabolic factors. Methods: Seventy five cases who underwent LSG between 2011 and 2015 and were postoperatively followed-up for 12 months at the Toho University Sakura Medical Center were included in the analysis of the cross-sectional survey at baseline, and 33 cases were included in the analysis of the longitudinal survey during the 12 months after LSG. We evaluated body composition, glycolipid parameters, liver/renal function, as well as serum s(P)RR level and ATP6AP2 mRNA expression level in VAT and SAT. Results: The mean serum s(P)RR level at baseline was 26.1 ng/mL, this value was considered higher than values in healthy subjects. There was no significant difference in the expression level of ATP6AP2 mRNA between VAT and SAT. At baseline, multiple regression analysis for the association between s(P)RR and variables identified that visceral fat area, HOMA2-IR, and UACR showed the independent relationships with s(P)RR. During the 12 months after LSG, body weight, serum s(P)RR level showed a significant decrease (from 30.0 +/- 7.0 to 21.9 +/- 4.3). Multiple regression analysis for the association between the change in s(P)RR and variables showed that changes in visceral fat area, and alanine transaminase were independently related to the change in s(P)RR. Conclusion: This study showed that blood s(P)RR level was high in severely obese patients, decreased with weight loss by LSG, and was associated with visceral fat area in both pre- and postoperative changes. The results suggest that blood s(P)RR levels in obese patients may reflect the involvement of visceral adipose (P)RR in insulin resistance and renal damage mechanisms associated with obesity.