Serum-Free Culture with PVP Enables Maintenance of Primary Culture of Parathyroid Cells In Vitro

The parathyroid gland is a critical endocrine organ responsible for maintaining serum calcium homeostasis through the secretion of parathyroid hormone (Pth). Parathyroid tissue can be irreversibly lost due to autoimmune diseases or surgical injury, and the absence of appropriate model cells has hindered drug discovery targeting this cell type. Therefore, there is a strong need to develop in vitro culture systems for normal parathyroid cells for both cell therapy and pharmacological research. In this study, we identified a serum-free culture system supplemented with B27 and polyvinylpyrrolidone (PVP) that enables the maintenance of parathyroid-like cells. These cells retained expression of key markers such as calcium-sensing receptor (CaSR) and Pth and exhibited slow but consistent colony formation and proliferation. Notably, the cultured cells were highly sensitive to serum exposure; the addition of 10% Fetal Bovine Serum (FBS) rapidly induced epithelial-to-mesenchymal transition (EMT)-like changes and a marked loss of functional gene expression. These findings not only provide a foundational strategy for culturing parathyroid cells but also highlight their inherent vulnerability to phenotypic and functional deterioration.