PP.LB02.27: IS RENALASE BLOOD PRESSURE REGULATOR IN HEMODIALYSIS PATIENTS?

Objective: Renalase is an enzyme that circulates in the blood and modulates the cardiac function, sympathetic tone and systemic blood pressure. It can be synthesized in the kidneys, liver and cardiomyocytes. The active enzyme degrades circulating catecholamines, causing a significant fall in blood pressure. Changes in renalase concentration in hemodialysis patients may explain the frequent occurrence of hypertension among patients with end-stage kidney disease. The aim of this study was to asses’ serum renalase levels in hemodyalisis patients and apparently healthy subjects, and association of renalase and blood pressure in patients group. Design and method: 160 subjects were recruited in the study: 120 with end-stage renal disease, divided into two groups, according to their blood pressures (normotensive and hypertensive), and 40 apparently healthy individuals matched in age and sex. Blood pressure was measured before and after a hemodialysis session. The target values, according to ESH/ESC guidelines, were lower than 140/90 mmHg before, and 130/90 mmHg after hemodialysis. The blood for the estimating serum renalase concentration was taken before dialysis. Enzyme-linked immunosorbent assay (ELISA) kit with monoclonal antibody specific to renalase, was used. Results: Mean serum renalase levels in normotensive as well as hypertensive hemodialysis patients were significantly higher compared to control group {89.32 (45.77–170.22) and 42.7 (32.79–63.35) &mgr;g/ml, respectively; p < 0.0005}. No significant difference of renalase levels among normotensive and hypertensive patients was noted {64.04 (40.76–173.84) and 91.86 (56.77–149.75.35)&mgr;g/ml; (p > 0.05)}. There was a highly significant difference between systolic and diastolic pressure measured before and after the dialysis in normotensive and hypertensive groups of patients (p < 0.0005). It was noted that there is a significant, negatively directed association between patients’ age at the beginning of dialysis and the duration of hemodialysis. Also, the correlation between blood pressure and renalase activity among normotensive and hypertensive hemodialysis patients was not shown (p > 0.05). Conclusions: Further studies are needed to define the role of renalase and its complex pathophysiological link with blood pressure regulation, kidney function and sympathetic tone. Renalase may become a new therapeutic target that leads to a better prognosis for patients with end-stage kidney disease.