Association between circulating PCSK9 and proteinuria in nephrotic syndrome: A cross-sectional study

Background: Nephrotic syndrome (NS) is associated with both hypercholesterolemia and hypertriglyceridemia, which could exacerbate disease progression and accelerate atherosclerosis. It has been reported that PCSK9, a proprotein convertase involved in hypercholesterolemia, was increased in patients with NS.Objective: To investigate the association between PCSK9 concentrations and the magnitude of proteinuria.Methods: A total of 168 patients from nephrology and lipid clinics of the Centre Hospitalier de l'Universite acute accent de Montreal were included in this cross-sectional observational study. Proteinuria level was classified in three groups: nephrotic syndrome (n = 51), proteinuria (n = 66), and control (n = 51) according to proteinuria and albuminemia concentrations. Plasma PCSK9 concentration was measured by an in-house ELISA and the lipid profile was assayed using an automated biochemical analyzer (COBAS INTEGRA 400, Roche Diagnostic).Results: Plasma PCSK9 concentration was highest in the NS group (170.9 ng/mL), intermediate in the proteinuria group (156.4 ng/mL) and lowest in the control group (136.0 ng/mL), P = 0.005. We observed an association between the protein/creatinine (P/C) ratio and plasma PCSK9 concentrations in the whole cohort (beta = 0.205, P = 0.006) after adjustment for age, sex, LDL-C, statin use, other lipid-lowering therapy use, diabetes, and eGFR.Conclusions: Patients with nephrotic syndrome have an increased risk of cardiovascular complications. PCSK9 is significantly elevated in NS and is associated with a detrimental lipid profile that could contribute to a worse prognosis of the disease. Future studies evaluating the efficacy of PCSK9 inhibitors in patients with NS would be justified.