NDT Advance Access published online on November 5, 2008
Nephrology Dialysis Transplantation, doi:10.1093/ndt/gfn579
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Regression of parathyroid gland swelling by treatment with cinacalcet
Nephrol Dial Transplant 2008; doi:10.1093/ndt/gfn587Sir,
Calcimimetic compounds, such as cinacalcet, reduce parathyroid hormone (PTH) secretion in patients with secondary hyperparathyroidism, as Fukagawa et al. demonstrated in the recent NDT article [1]. However, whether calcimimetic compound can reduce the size of an already-swollen parathyroid gland (PTG) is unclear. Here we report our observations of changes in the PTG size in a single case of secondary hyperparathyroidism treated with cinacalcet.
The patient was a 59-year-old woman who had been receiving haemodialyis since December 2003 for nondiabetic end-stage renal failure. In December 2006, elevated levels of serum intact PTH and alkaline phosphatase (ALP) were found (Table 1). Ultrasound examination revealed swelling of the right upper, right lower and left upper lobes of the PTG. Intravenous administration of the vitamin D analogue maxacalcitol (Oxarol®, Chugai Pharmaceutical Co., Ltd, Tokyo, Japan) reduced the levels of both intact PTH and ALP; however, the PTG (especially the left upper lobe) gradually enlarged, and the product of the serum levels of calcium and inorganic phosphorus (Ca x Pi) reached 100 mg2/dL2.
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In February 2008, cinacalcet tablets (Regpara®, Kirin Pharma Co., Ltd, Tokyo, Japan) were prescribed. A low dose of cinacalcet (25 mg/day; February through April 2008) shrank the right upper and lower lobes of the PTG but did not affect the size of the left upper lobe. The dose of cinacalcet was increased in March 2008 (50 mg/day), and, as a result, the size of all PTG lobes decreased (Table 1).
The present observation suggests that (1) cinacalcet can reduce the size of PTG, and that (2) the sensitivity of the lobes of the PTG to cinacalcet can differ within a single patient. Regarding the first point, Mizobuchi et al. have reported that a high concentration of calcimimetic agent induces apoptosis in cultured hyperplastic parathyroid cells [2]. Regarding the second point, Kawata et al. have reported that the suppressive effect of cinacalcet on PTH secretion correlates negatively with the degree of calcium-sensing receptor expression in a rat model [3].
To our knowledge, this is the first report showing that cinacalcet can reduce the size of the PTG in a clinical setting. Considering the case report by Lazar and Stankus that cinacalcet can induce hungry-bone syndrome, as does parathyroidectomy [4], treatment with cinacalcet might be a curative treatment for secondary hyperparathyroidism, as is parathyroidectomy.
Conflict of interest statement. None declared.
1 Department of Kidney and Hypertension, The Jikei University School of Medicine, Tokyo 2 Department of Internal Medicine Kashima Hospital, Iwaki Fukushima 3 Research Division of Dialysis and Chronic Kidney Disease, Tohoku University Graduate School of Medicine, Sendai, Miyagi 4 Academic Information Center, The Jikei University School of Medicine, Tokyo, Japan
References
- Fukagawa M, Yumita S, Akizawa T, et al. Cinacalcet (KRN1493) effectively decreases the serum intact PTH level with favourable control of the serum phosphorus and calcium levels in Japanese dialysis patients. Nephrol Dial Transplant (2008) 23:328–335.
[Abstract/Free Full Text] - Mizobuchi M, Ogata H, Hatamura I, et al. Activation of calcium-sensing receptor accelerates apoptosis in hyperplastic parathyroid cells. Biochem Biophys Res Commun (2007) 362:11–16.[CrossRef][Web of Science][Medline]
- Kawata T, Imanishi Y, Kobayashi K, et al. Relationship between parathyroid calcium-sensing receptor expression and potency of the calcimimetic, cinacalcet, in suppressing parathyroid hormone secretion in an in vivo murine model of primary hyperparathyroidism. Eur J Endocrinol (2005) 153:587–594.
[Abstract/Free Full Text] - Lazar ES, Stankus N. Cinacalcet-induced hungry bone syndrome. Semin Dial (2007) 20:83–85.[CrossRef][Web of Science][Medline]
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