Xenotransplantation of human cryopreserved parathyroid tissue isolated from parathyroid adenomas to normocalcemic rabbits

Abstract

Objective: Parathyroid allotransplantation is a new method for the treatment of permanent hypoparathyrodism. Adenoma cells are not used for transplantation because of the potential for functional or histopathologic transformation. In this study, we transplanted human adenomatous parathyroid cells to rabbits. Material and Methods: Parathyroid adenoma tissue taken from a male patient was cryopreserved and transplanted into seven New Zealand white rabbits (mean weight, 3700±220 g; mean age, 4.5 months) under immunosuppression. The levels of parathormone, calcium and phosphorus were measured before and after transplantation, and the parathyroid cells were observed histopathologically. Results: Mean parathyroid hormone level was 0.5 pg/dL before transplantation and 6.6 pg/dL after transplantation (p<0.05). Preoperative mean calciumlevel was 14.1 mg/dL, and mean phosporus level was 3.5 mg/dL before transplantation while these values were 14.4 mg/dL and 3.3mg/dL, respectively, after transplantation (p>0.05). Morphologic transformation was not observed in parathyroid cells after transplantation. Conclusion: In short-term observation, adenomatous parathyroid cells can function without malignant transformation. In the future, the preliminary methodology in this study may serve as a safe alternative for allotransplantation into patients with permanent hypoparathyroidism. Keywords: Hypoparathyroidism, xenotransplantation, parathyroid adenoma