Parathyroid hormone content distinguishes true normal parathyroids from parathyroids of patients with primary hyperparathyroidism

The purpose of this study was to clarify the pathophysiology of primary hyperparathyroidism by looking for differences between parathyroids from eucalcemic patients and patients with primary hyperparathyroidism (HPT) with respect to the following parameters: intracellular parathyroid content of parathyroid hormone (PTH) and parathyroid hormone messenger RNA (PTH mRNA); and serum PTH and calcium levels of patients and patient age. Coded samples of human parathyroid biopsies were assayed for PTH content with a C-terminal-specific radioimmunoassay. Total cellular RNA was extracted, and PTH mRNA was quantified by dot-blot analysis. These results were tabulated along with associated data on patient age, preoperative serum PTH, and preoperative calcium levels. The content of PTH was significantly higher in true normal (TN) parathyroids than in parathyroids from patients with hyperparathyroidism. PTH content of adenomas and hyperplasias were similar. PTH content of normal parathyroids biopsied from patients with parathyroid adenomas (NA) was statistically higher than that of adenomas but statistically lower than that of TN parathyroids. PTH mRNA and PTH content were correlated (p < 0.001) for TN parathyroid glands; however, it was not true for glands (grossly normal or otherwise) in patients with HPT. Patient groups were similar with regard to mean patient age and intracellular PTH mRNA levels. Hypercalcemic patients were similar with regard to preoperative serum calcium and PTH levels. NA parathyroids, adenomas, and hyperplasias are different from TN parathyroids with regard to their PTH content. PTH mRNA was similar across all groups. The relation between intracellular PTH mRNA and PTH was significantly absent in patients with HPT compared with TN glands. Furthermore, we have found that PTH content of normal parathyroid in patients with adenoma is similar to that of hyperplastic and adenoma tissues. These data suggest that the PTH content of parathyroid tissues may be of use in differentiating normal from abnormal parathyroids.

DNA index and ploidy distinguish normal human parathyroids from parathyroid adenomas and primary hyperplastic parathyroids

BACKGROUND

The goal of this study was to identify factors that might aid in diagnosis and intraoperative management of hyperparathyroidism.

METHODS

We analyzed biopsy specimens of 242 parathyroids from 159 patients by use of flow cytometry and image cytometry (ICM) for DNA index (DI), defined as the content of nuclear DNA compared with that expected for a DNA diploid standard, for proliferative index (PI), and for ploidy (diploid versus aneuploid or tetraploid).

RESULTS

True normal and normal parathyroids from patients with solitary adenomas were uniformly diploid. Abnormal ploidy (aneuploidy or tetraploidy) was identified frequently in adenomas and occasionally in hyperplasias with the exception that multiple endocrine neoplasia (MEN) biopsy specimens were uniformly diploid. DI for adenomas was similar to that for hyperplasias, and DI of both was higher than for normal glands. ICM-DI correlated positively with flow cytometry-DI and patient age and inversely with serum parathyroid hormone. PI was relatively low in all groups but was higher for hyperplasias versus normal parathyroids from patients with solitary adenomas and MEN versus non-MEN. PI correlated inversely with patient age.

CONCLUSIONS

DI by ICM differentiates normal from abnormal parathyroids. DI might influence extent of resection in two- and three-gland hyperplasia and selection of the most appropriate gland for autografting and cryopreservation in patients with four-gland hyperplasia.