Transplantation of human cryopreserved adenomatous and hyperplastic parathyroid tissue to the hypocalcemic Nude mouse

Cryopreserved parathyroid glands from patients operated on for hyperparathyroidism were stored for further auto‐ or allografting. In an attempt to better use cryopreserved parathyroid glands in humans, we designed a study whose goal was to compare human parathormone (hPTH) secretion from cryopreserved parathyroid glands with regard to tissue histology (adenoma or hyperplasia), mass, and time of storage in hypocalcemic Nude mice and to be able to better use them in humans. A new hypocalcemic experimental model, using parathyroidectomized Nude mice was set up. Hypocalcemicmice received calibrated grafts from human parathyroid glands cryopreserved between 1982 and 1992 originating from 30 patients (15 adenomas, 15 hyperplasias). Each parathyroid was grafted into two mice under the ratio of one mass‐unit (12 mg) and three mass‐units (36 mg). The hPTH concentration was assessed by an immunoradiometric method 21 days after grafting. The mean cryopreservation time was 677 days (54–3187 days). The time of cryopreservation was identical in the two kinds of tissue ( p =0.88). The hPTH concentration in 59 living mice was 72.2 ±271.4 (SD) ng/ml (3–1936 ng/ml). This concentration was 7.1 ±4.3 ng/L for adenomas versus 139.4 ±378.6 ng/L for hyperplasias ( p =0.003) and 87.1 ±352.6 ng/L for one‐unit‐mass grafts versus 56.7 ±152.5 ng/L for three unit‐mass grafts ( p =0.824). Hyperplastic glands showed more secretion, which was confirmed in both mass related groups ( p =0.02, p =0.006). The multiple linear regression showed no hPTH concentration difference related to mass or time of cryopreservation ( p >0.15), and it confirmed that the highest secretion of hPTH was in the hyperplastic tissues ( p =0.0001). These results show that cryopreservation preserves glands for several years, and that hyperplastic tissue preferentially should be used.