PARATHYROID-GLANDS IN UREMIC PATIENTS WITH REFRACTORY HYPERPARATHYROIDISM - HISTOPATHOLOGY AND P53 PROTEIN EXPRESSION ANALYSIS

Aims: Refractory hyperparathyroidism is a state of parathyroid hyperfu nction and hypercalcaemia in uraernic patients with previous secondary hyperplasia. We studied histopathological features and p53 expression in 49 parathyroid glands of uraemic patients (n=21) with refractory h yperparathyroidism in order to investigate whether p53 abnormalities c ould be present in parathyroid hyperplasias of chronic renal failure. Methods and results: Nodular hyperplasia was found in 77.5% of the gla nds (n = 38). The proportion of oxyphil cells and acinar cell arrangem ents was higher in nodular hyperplasia than in diffuse hyperplastic gl ands (P<0.001), Duration of renal disease and haemodialysis treatment tended to be longer in patients with nodular hyperplasia, There was no correlation between serum intact PTH (iPTH), calcium and hyperplasia pattern, A trend for a higher glandular mass was found in nodular type hyperplasia (1.88 +/- 2.13 g) than in diffuse type hyperplasia (0.87/-1.28g; P=0.06). Nuclear p53 immunoreactivity was shown in 55% of the hyperplastic glands, whereas it was not detected in 12 normal parathy roid glands used as controls. p53 staining was present in c, 82% of th e diffuse hyperplastic glands and in 47% of the nodular hyperplastic g lands (P=0.08), Conclusions: Nodular type hyperplasia was the predomin ant histopathological pattern in uraemic patients with refractory hype rparathyroidism in our study. Nodular hyperplastic glands characterist ically had higher percentage of oxyphil cells, acinar cell arrangement s and mass than diffuse hyperplastic glands. A high prevalence of p53 protein expression was found in hyperplastic glands of uraemic patient s. Our results suggest that p53 abnormalities might be involved in the pathogenesis of parathyroid hyperplasia in chronic renal failure.