Decreased blood lead levels after calcitriol treatment in hemodialysis patients with secondary hyperparathyroidism

ObjectiveSecondary hyperparathyroidism (SHP) is characterized by high bone turnover, which may, in turn, result in increased release of lead from bone stores. This study investigated the effects of intravenous calcitriol on blood lead (BL) levels in patients with SHP.MethodsIntravenous calcitriol therapy was administered for 16 wk to 28 patients who were on maintenance hemodialysis (HD) and had intact parathyroid hormone (iPTH) plasma levels of > 300 pg/mL. Blood was drawn at baseline and every 4 wk for 16 wk to determine the levels of iPTH; bone remodeling markers, including bone-specific alkaline phosphatase (bAP) and type 5b tartrate-resistant acid phosphatase (TRAP); and BL.ResultsOf the 28 patients, 25 responded to calcitriol therapy; they exhibited significant decrements in serum iPTH levels by the end of 4 wk of therapy and thereafter. After 16 wk of therapy, these patients had significant reductions in serum iPTH levels (p < 0.01) and significant and parallel decreases in the levels of bAP (p < 0.01), TRAP (p < 0.01), and BL (p < 0.01). Further analysis showed a significant positive correlation between the levels of BL and serum iPTH (r = 0.34, p < 0.01) and BL and serum TRAP (r = 0.22, p < 0.05). However, there was no significant correlation between the levels of BL and serum bAP.ConclusionElevated levels of BL and serum bone remodeling markers, which are common features of SHP, can be effectively suppressed by calcitriol therapy. This indicates that hyperparathyroidism not only accelerates bone remodeling but may also enhance bone lead mobilization in patients on maintenance HD.

► Elevated levels of blood lead and serum bone remodeling markers are common features of secondary hyperparathyroidism (SHP). ► SHP accelerates bone remodeling and aggravates bone lead mobilization into blood pool. ► Calcitriol therapy can effectively suppress blood lead and bone remodeling markers.