Persistent hyperparathyroidism in renal allograft recipients: Vitamin D receptor, calcium-sensing receptor, and apoptosis

The phenotypic changes in parathyroid cells after successful renal transplantation remain to be elucidated. We compared 10 diffuse and 11 nodular hyperplastic parathyroid glands from five renal allograft recipients with persistent hyperparathyroidism, with five diffuse and 13 nodular hyperplasia from seven uremic patients on hemodialysis, and 13 normal glands. Comparisons included expressions of both vitamin D receptor (VDR) and calcium-sensing receptor (CaSR), proliferative activity (Ki67), and apoptosis (TUNEL). Immunoreactivity was assessed semiquantitatively and expressed as labeling index. The area/cell was also measured to assess cellular hypertrophy. The labeling indexes of VDR (587±71; mean±s.e.m.) and CaSR (45.0±2.8) in recipients’ diffuse hyperplasia were significantly higher than those in uremic diffuse hyperplasia (224±44, 29.3±2.3, respectively) (P<0.01, each). However, these expressions remained low in recipients’ nodular hyperplasia (42±8, 11.8±1.4, respectively). Ki67 labeling index in recipients’ nodular hyperplasia (7±1) was significantly smaller than in uremic patients (24±6, P