Co-expression of parathyroid hormone and chromogranin A in secondary hyperparathyroidism: a functional marker for secretory activity of hyperplastic nodules

Density-Dependent Differentiation of Tonsil-Derived Mesenchymal Stem Cells into Parathyroid-Hormone-Releasing Cells

Mesenchymal stem cells (MSCs) can differentiate into endoderm lineages, especially parathyroid-hormone (PTH)-releasing cells. We have previously reported that tonsil-derived MSC (T-MSC) can differentiate into PTH-releasing cells (T-MSC-PTHCs), which restored the parathyroid functions in parathyroidectomy (PTX) rats. In this study, we demonstrate quality optimization by standardizing the differentiation rate for a better clinical application of T-MSC-PTHCs to overcome donor-dependent variation of T-MSCs. Quantitation results of PTH mRNA copy number in the differentiated cells and the PTH concentration in the conditioned medium confirmed that the differentiation efficiency largely varied depending on the cells from each donor. In addition, the differentiation rate of the cells from all the donors greatly improved when differentiation was started at a high cell density (100% confluence). The large-scale expression profiling of T-MSC-PTHCs by RNA sequencing indicated that those genes involved in exiting the differentiation and the cell cycle were the major pathways for the differentiation of T-MSC-PTHCs. Furthermore, the implantation of the T-MSC-PTHCs, which were differentiated at a high cell density embedded in hyaluronic acid, resulted in a higher serum PTH in the PTX model. This standardized efficiency of differentiation into PTHC was achieved by initiating differentiation at a high cell density. Our findings provide a potential solution to overcome the limitations due to donor-dependent variation by establishing a standardized differentiation protocol for the clinical application of T-MSC therapy in treating hypoparathyroidism.

Spontaneous proliferative and neoplastic lesions in thyroid and parathyroid glands of nondomestic felids

Based on microscopic and immunohistochemical characterization, we documented spontaneous proliferative and neoplastic lesions in the thyroid and parathyroid glands of nondomestic felids. Ten animals (4 leopards, 3 tigers, and 3 cougars), all with a previous diagnosis of thyroid neoplasia were identified from the University of Tennessee College of Veterinary Medicine database. The mean age of affected animals was 15.9 y. Twelve neoplasms were identified; 2 animals had 2 concurrent neoplasms. After immunohistochemical characterization using a panel of chromogranin A, thyroglobulin, and calcitonin, 7 of the former thyroid neoplasms were diagnosed as thyroid adenomas, 1 was diagnosed as a thyroid carcinoma, and 4 were diagnosed as parathyroid adenomas. No thyroid medullary neoplasms (C-cell tumors) were diagnosed in the current study. Most of the diagnosed neoplasms were benign (11 of 12), and metastasis was not documented in the single carcinoma. Only 2 animals were suspected to have functional neoplasms (1 thyroid adenoma and 1 parathyroid adenoma), based on associated tissue lesions or serum biochemistry. Other documented lesions in the thyroid and parathyroid glands included thyroid nodular hyperplasia ( n = 7), parathyroid hyperplasia associated with chronic renal disease ( n = 2), a thyroid abscess, and a branchial cyst. Parathyroid adenomas were more commonly diagnosed than expected in comparison with domestic cats. We demonstrated that an immunohistochemistry panel for thyroglobulin, calcitonin, and chromogranin A can be used to differentiate neoplasms of thyroid from parathyroid origin in nondomestic felids.

Normocalcemic primary hyperparathyroidism in patients with recurrent kidney stones: pathological analysis of parathyroid glands

The lack of overt elevation of serum calcium concentration in some patients suffering from primary hyperparathyroidism is an intriguing clinical phenomenon. Previous studies have substantiated abnormal parathyroid tissue in these patients, but the extent and mode of derangements remained largely undefined. The parathyroid tissues from patients of normocalcemic primary hyperparathyroidism (NCPHPT) and those having normal parathyroid glands, hypercalcemic primary hyperplasia, secondary hyperplasia, and adenoma were compared by undertaking quantitative immunohistochemistry analysis on tissue microarray. The statistic results suggested that the parathyroid tissue of NCPHPT approximates more to normal gland than to its counterpart in other groups of parathyroid proliferative diseases in terms of the lack of significant alterations of calcium-sensing receptor (CaSR), chromogranin A (CGA), parathyroid hormone (PTH), and proliferation index (Ki67). On the other hand, the depressed vitamin D receptor (VitDR) and elevated cyclin D1 (CyD1) of NCPHPT indicated the inherent functional abnormalities in parathyroid cells. Our results imply that inherent functional disengagement may exist between CaSR and CyD1 or between CaSR and VitDR or both in parathyroid cells of symptomatic NCPHPT. Lack of enhanced release of CGA and PTH and discordance between proliferative activity and CyD1 expression in parathyroid cells may further hinder the development of hypercalcemia.