Development and application of primary rat parathyroid cells for transplantation in hypoparathyroidism

BACKGROUND: Hypoparathyroidism (HPO) is characterized by deficient secretion of parathyroid hormone (PTH), leading to hypocalcemia and disrupted calcium homeostasis. Current treatments rely on calcium and vitamin D supplementation, which do not adequately mimic physiological PTH function. Cell-based therapies offer a potential solution, but optimal culture conditions to preserve the functional properties of primary parathyroid cells remain unclear. This study aims to develop primary rat parathyroid cell cultures that maintain hormone secretion and calcium-sensing abilities and to evaluate their therapeutic potential in a rat model of HPO. METHODS: An HPO model was established in rats through surgical excision of the parathyroid glands. Primary parathyroid cells were isolated from these rats and sorted by flow cytometry using epithelial cell adhesion molecule (EpCAM) and calcium-sensing receptor (CaSR) markers. Four different culture media (CM) were tested to determine optimal conditions for sustaining cell functionality. The most effective CM was supplemented with Sonic Hedgehog (Shh), Activin A, and inhibitors of epithelial-mesenchymal transition (EMT). The cultured cells were then transplanted into HPO rats, and serum calcium and PTH levels were monitored to assess therapeutic efficacy. RESULTS: The optimized CM successfully preserved the hormone-secreting and calcium-sensing functions of primary parathyroid cells over multiple passages. Transplanted cells in HPO rats led to a significant increase in serum calcium and PTH levels compared to untreated controls. The restoration of these levels correlated with the alleviation of hypocalcemic symptoms, indicating effective functional integration of the transplanted cells. CONCLUSIONS: Primary rat parathyroid cells cultured under optimized conditions retained essential functional properties and, upon transplantation, effectively restored calcium homeostasis in an HPO rat model. These results highlight the potential of using cultured primary parathyroid cells as a viable cell-based therapy for HPO, offering a promising alternative to conventional treatments.