New acquisitions in therapy of secondary hyperparathyroidism in chronic kidney disease and peritoneal dialysis patients : role of vitamin D receptor activators

Secondary hyperparathyroidism is a serious complication of chronic renal disease when function decline and is characterized by abnormalities in serum calcium and phosphate profile, along with a decline in calcitriol synthesis. A reduced density of specific receptors for vitamin D and calcium in several tissues and organs are also present, thus contributing to parathyroid hyperplasia and abnormal parathyroid hormone synthesis and secretion. This metabolic derangement is observable early in the course of chronic renal failure (stages 3 and 4) and on this basis it should also be treated early in order to avoid important clinical consequences. To afford secondary hyperparathyroidism, several strategies should be considered: phosphate oral intake control (diet and phosphate binders), adequate calcium oral intake, vitamin D receptor activation. More specifically, the concept of selective vitamin D receptor activation will be considered as well as its biological effects, the use of paricalcitol (a selective vitamin D receptor activator) given orally to patients on peritoneal dialysis, and stages 3 and 4 of chronic renal failure. Finally, we will consider a series of nonclassical interesting potential mechanisms of selective vitamin D receptor activation leading to reduced cardiovascular and all-cause mortality.