Upacicalcet, a positive allosteric modulator of the calcium-sensing receptor, prevents vascular calcification and bone disorder in a rat adenine-induced secondary hyperparathyroidism model.

Hirofumi Sato, Moritaka Goto, Go Nishimura, Nobutaka Morimoto, Hiroki Tokushima, Yusuke Horii, Naoki Takahashi

Bone 2023 Feb

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Secondary hyperparathyroidism (SHPT) is a major comorbidity of chronic kidney disease (CKD). Chronic elevation of PTH levels is associated with cortical bone deterioration and increase in the risk of fractures in CKD patients. Here, we evaluated the effect of repeated administration of upacicalcet, a novel positive allosteric modulator of the calcium-sensing receptor, in a rat model of adenine-induced renal failure, by determining serum levels of intact PTH (iPTH), calcium, phosphorus, creatinine, and urea nitrogen. Furthermore, parathyroid hyperplasia (parathyroid gland weight and Ki-67-positive cell density), ectopic calcification (calcium content in the thoracic aorta, kidney and heart and positive von Kossa staining in the thoracic aorta), and bone morphometry parameters (cortical porosity and fibrosis volume) were evaluated. Rats treated with either 0.2 mg/kg or 1 mg/kg upacicalcet exhibited significantly lower serum iPTH levels than CKD-control rats, as early as 7 days after the first dose. Repeated administration of upacicalcet reduced serum iPTH levels and inhibited parathyroid hyperplasia in rats with adenine-induced severe renal failure. Moreover, it suppressed ectopic calcification and cortical pore formation. In contrast, serum calcium and phosphorus levels were not significantly affected, suggesting a low risk of hypocalcemia, which often occurs with SHPT treatment. In conclusion, repeated administration of upacicalcet decreased serum iPTH levels and suppressed parathyroid hyperplasia in the adenine-induced CKD rat model of SHPT. Furthermore, ectopic calcification and cortical pore formation were suppressed without significant changes in blood mineral parameters. Upacicalcet safely inhibited the progression of SHPT in an adenine-induced CKD rat model. Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.

Citation

Hirofumi Sato, Moritaka Goto, Go Nishimura, Nobutaka Morimoto, Hiroki Tokushima, Yusuke Horii, Naoki Takahashi. Upacicalcet, a positive allosteric modulator of the calcium-sensing receptor, prevents vascular calcification and bone disorder in a rat adenine-induced secondary hyperparathyroidism model. Bone. 2023 Feb;167:116613