Bone Status and Circulating Sclerostin Levels Differ among Patients with Different Parathyroid Disorders

Abstract

Parathyroid Hormone (PTH) shows both catabolic or anabolic actions on the skeleton and the anabolic actions of PTH are mainly mediated by inhibition of sclerostin expression in osteocytes. Different parathyroid disorders show different effects on bone status and circulating sclerostin levels. Studies regarding bone status including bone mass and bone turnover markers in pseudohypoparathyroidism are sparse and get inconsistent results. Previous studies suggested that pseudohypoparathyroidism may show partial resistance to PTH in skeleton. Therefore, we hypothesized that the bone status in pseudohypoparathyroidism may be between hyperparathyroidism and hypoparathyroidism. Therefore, this study was designed to compare the bone status including bone density and bone turnover markers, as well as circulating sclerostin levels, among patients with different parathyroid disorders. A total of 216 patients with hyperparathyroidism, pseudohypoparathyroidism and hypoparathyroidism were collected. Results showed that the Bone Mineral Density (BMD) of Lumbar Spine (LS), Femoral Neck (FN) and Total Hip (TH) were gradually decreased in hyperparathyroidism, pseudohypoparathyroidism and hypoparathyroidism. The levels of bone turnover markers were comparable between hyperparathyroidism and pseudohypoparathyroidism, and were significantly higher than those of hypoparathyroidism. Serum sclerostin levels were significantly lower in hyperparathyroidism. In hyperparathyroidism, sclerostin was positively correlated with BMD of LS and FN. In pseudohypoparathyroidism, sclerostin was positively associated with BMD of LS. Our study suggested that the bone status in pseudohypoparathyroidism is between hyperparathyroidism and hypoparathyroidism, and circulating sclerostin levels are different among patients with different parathyroid disorders and are correlated with BMD of LS and FN in hyperparathyroidism and pseudohypoparathyroidism.