Abstract 2189: Clinical Significance of Urinary Aquaporin-2 Protein Excretion in Patients with Chronic Heart Failure
Objectives. It is reported that patients with chronic heart failure (CHF) have decreased ability to excrete water and increased urinary excretion of aquaporin-2 (U-AQP2). However, the significance and affecting parameters of U-AQP2 excretion remains controversy. We investigated the U-AQP2 excretion in CHF patients by ELISA methods.
Methods. 140 cases of CHF with symptoms(NYHA II~IV), 92 cases of CHF without symptoms(NYHA I), and 102 cases of healthy subjects were studied. Plasma concentrations of vasopressin (AVP) and brain natriuretic peptides (BNP) were measured by radioimmunoassays. U-AQP2 was determined by ELISA methods. Left ventricle hypertrophy was determined by Echocardiography.
Results. U-AQP2 was increased significantly in CHF patients as compared with healthy subjects (161±141 vs 126±54 fmol/Umol, p<0.01), while there was no difference between CHF patients with symptoms and without symptoms (169±150 vs 153±124 fmol/Umol, p>0.05). CHF with edema(n=53) had higher U-AQP2 than those without edema(n=179, 199±124 vs 142±101 fmol/Umol, p<0.05). CHF with LV hypertrophy(n=156) had higher U-AQP2 than those without LV hypertrophy (n=61, 204±168 vs 128±109 fmol/Umol, p<0.005). U-AQP2 was increased by aging of CHF patients (age<45y, between 45~75y and >75y were 95±60, 168±132 and 253±178 fmol/Umol, respectively, p<0.001). Diuretics and ACEI might increase U-AQP2. However, there were no significant correlations between U-AQP2 and Sex, LVEF, plasma AVP or BNP Levels.
Conclusions. Urinary AQP2 excretion might be a useful tool for evaluating water metabolism in CHF. The increased U-AQP2 in CHF Patients was affected by a lot of clinical manifestations. Increased urinary AQP2 levels suggest that an activation of apical membrane targeting of AQP2 may occur in CHF patients.