Kidney and hypertension: is there a place for renalase?

Chronic kidney disease (CKD) is associated with a considerably higher risk of cardiovascular disease due to the presence of traditional and nontraditional risk factors. Hypertension occurs in approximately 80% to 85% of the patients with CKD and its etiology is multifactorial. The sympathetic nervous system activity is enhanced in patients witch CKD resulting in increased vascular resistance and systemic blood pressure. This enhanced activity is the result of overspill and reduced catecholamine clearance. Recently, a new protein was discovered, named renalase. Experimental in vitro studies showed that renalase degrades catecholamines and thus may have a significant hemodynamic effect in vivo, for example may decrease cardiac contractility, heart rate, and blood pressure. Studies conducted in CKD and hemodialysis patients demonstrated lower serum renalase levels compared with healthy individuals. Other studies revealed increased serum renalase levels in dialysis population and kidney transplant recipients. There are no data concerning the association between renalase gene expression and activity/concentration and function of renalase; thus, it has to be proved in further studies that renalase is not an innocent bystander but is involved in the pathogenesis of hypertension.