The Role of the L-Arginine–Nitric Oxide Molecular Pathway in Autosomal Dominant Polycystic Kidney Disease

Abstract

Recently, arginine has been proven to play an important role in ADPKD physiopathology. Arginine auxotrophy in ADPKD induces cell hyperproliferation, blocking the normal differentiation of renal tube cells and causing cyst formation. We explored the L-arginine (Arg)–nitric oxide (NO) molecular pathway in ADPKD, a multisystemic arginine auxotrophe disease. We developed a prospective case–control study that included a group of 62 ADPKD subjects with an estimated filtration rate over 60 mL/min/1.73 mp, 26 subjects with chronic kidney disease with an eGFR > 60 mL/min/1.73 mp, and a group of 37 healthy subjects. The laboratory determinations were the serum level of arginine, the enzymatic activity of arginase 2 and inducible nitric oxide synthase, the serum levels of the stable metabolites of nitric oxide (nitrate, direct nitrite, and total nitrite), and the endogenous inhibitors of nitric oxide synthesis (asymmetric dimethylarginine and symmetric dimethylarginine). In the ADPKD group, the levels of the arginine and nitric oxide metabolites were low, while the levels of the metabolization enzymes were higher compared to the control group. Statistical analysis of the correlations showed a positive association between the serum levels of Arg and the eGFR and a negative association between Arg and albuminuria. ADPKD is a metabolic kidney disease that is auxotrophic for arginine. Exploring arginine reprogramming and L-Arg–NO pathways could be an important element in the understanding of the pathogenesis and progression of ADPKD.