Increases in bone marrow fat (BMF) have been associated with skeletal fragility, particularly in obesity and type 2 diabetes. The parathyroid hormone (PTH) is one of the mechanisms that inhibits adipogenesis by acting on the bone marrow mesenchimal stem cells. There have been no study assessing the BMF in conditions of PTH deficiency.
Chronic hypoparathyroidism is a rare disorder characterized by low or undetectable PTH and low serum calcium levels. Bone mineral density (BMD) and bone quality are normal or increased compared to healthy subjects. It is not clear whether these or other features of the hypoparathyroid skeleton could potentially translate into increased skeletal fragility. In this context, the BMF has not been investigated in hypoparathyroidism.
The primary endpoint is to assess BMF and how it could be related with skeletal fragility in hypoparathyroidism. Mechanisms associated with the increase in BMF in the setting of chronic low PTH levels will be explored.
The project will recruit 60 patients with hypoparathyrodism and 60 age and sex-matched healthy subjects. All participants will undergo L1-L4 vertebrae 3 Tesla Magnetic Resonance Imaging to assess the proton density fat fraction; L1-L4, femoral neck, 1/3 radius MD and total body dual X ray absorptiometry (DXA) for BMD and fat and lean mass measurements, and vertebral fracture assessment by DXA. Serum levels of bone tunorver markers, and mineral metabolism parameters will be measured.
Results from the study will comprehensively define for the first time new features of the skeleton in hypoparathyroidism and mechanisms through which they could potentially be associated with skeletal fragility.
