Serum aquaporin-1 increases with heart failure and aortic valve surgery with cardiopulmonary bypass.

IntroductionSerum aquaporin-1 increases with inflammation and edema. However, its role as a cardiovascular biomarker remains unexplored. The goal of this study is to evaluate serum aquaporin-1 concentrations across two distinct clinical settings characterized by myocardial stress and congestion: acute heart failure and surgical aortic valve replacement with cardiopulmonary bypass.MethodsThis observational study included healthy volunteers (n = 8), acute heart failure patients (n = 11), and surgical aortic valve replacement patients (n = 11). Serum aquaporin-1 was measured using ELISA. Myocardial biopsies were obtained for aquaporin-1 and aquaporin-4 protein quantification before and after cardiopulmonary bypass in six patients.ResultsSerum aquaporin-1 levels were significantly higher in acute heart failure (3,921 ± 1,396 pg/mL; p = 0.0006) and surgical aortic valve replacement patients (3,318 ± 1,394 pg/mL; p = 0.0070) compared to healthy volunteers (1,755 ± 807 pg/mL). These differences remained significant after adjusting for sex and age. All patients with low cardiac output had serum aquaporin-1 concentrations in the upper half of their group distribution. Serum aquaporin-1 correlated moderately with B-type natriuretic peptide (r = 0.40; p = 0.0265), C-reactive protein (r = 0.42; p = 0.0203), and erythrocyte sedimentation rate (r = 0.45; p = 0.0117). Following cardiopulmonary bypass, myocardial aquaporin-1 increased (73%; p = 0.0310), while aquaporin-4 decreased (53%; p = 0.0440), with a strong but non-significant correlation between cardiac and serum aquaporin-1 changes.ConclusionSerum aquaporin-1 levels are elevated in acute heart failure and post-surgical aortic valve replacement patients, particularly in those with low cardiac output.