ATHEROSCLEROSIS IN UREMIA - POSSIBLE ROLES OF HYPERPARATHYROIDISM ANDINTERMEDIATE DENSITY LIPOPROTEIN ACCUMULATION

Cardiovascular motality is high in patients with chronic renal failure treated with dialysis, and secondary hyperparathyroidism may promote atherosclerogenesis. Recent studies have revealed advanced atheroscler osis in hemodialysis patients by using high-resolution B-mode ultrason ography. Multiple regression analyses indicated that hyperphosphatemia and hyperparathyroidism were associated with increased intima-media t hickness (IMT) of the carotid and femoral arteries in hemodialysis pat ients, respectively. Hypocalcemia and hyperparathyroidism independentl y and adversely affect the lipoprotein profile by suppressing hepatic triglyceride lipase (HTGL), a lipid-regulating enzyme playing importan t roles in the metabolism of intermediate density lipoprotein (IDL) an d high density lipoprotein (HDL). Plasma IDL is raised markedly, and H DL is lowered in uremia. These lipoprotein changes are closely associa ted with increased aortic pulse wave velocity (PWV), an index of aorti c sclerosis. These findings support the hypothesis that deranged calci um-phosphate homeostasis and secondary hyperparathyroidism promote ath erosclerosis in uremia, at least partly by affecting lipoprotein metab olism. Adequate dialysis and efforts to normalize calcium, phosphate a nd PTH would be beneficial in preventing not only bone disease, but at herosclerosis as well.