Apoptosis in Primary Hyperparathyroidism.

Primary hyperparathyroidism (PHPT) is defined by inappropriate elevation of parathormone, caused by parathyroid hyperplasia, also known as multi-gland disease (MGD), parathyroid adenoma (PA), or parathyroid carcinoma (PC). Although several studies have already been conducted, there is a lack of a definite diagnostic marker, which could unambiguously distinguish MGD from PA or PC. The accurate and prompt diagnosis has the key meaning for effective treatment and follow-up. This review paper presents the role of apoptosis in PHPT. The comparison of the expression of Fas, TRAIL, BCL-2 family members, p53 in MGD, PA, and PC, among others, was described. The expression of described factors varies among proliferative lesions of parathyroid gland; therefore, these could serve as additional markers to assist in the diagnosis.

Oxidative stress in proliferative lesions of parathyroid gland.

BACKGROUND: Primary hyperparathyroidism (PHPT) is one of the most common endocrine disorders and defined as excessive secretion of parathormone. PHPT is a risk factor of several cardiovascular diseases, which could be caused by alterations in oxidant-antioxidant balance. MATERIALS AND METHODS: Blood serum collected from 52 consecutive patients with PHPT treated surgically constituted our study material, whereas 36 healthy volunteers were our control group. Oxidative stress was evaluated in both patients and control subjects by assessment of malondialdehyde (MDA) and lipid hydroperoxides (LHP). Antioxidants were evaluated by the measurement of superoxide dismutase (SOD), ceruloplasmin (CER), catalase (CAT), sulfhydryl (SH) groups, glutathione (GSH), glutathione peroxidase (GSH-Px), glutathione transferase activity (GST) and glutathione reductase (GR). Moreover total antioxidant capacity (TAC) and total oxidative status (TOS) were measured and oxidative stress index (OSI) was calculated. RESULTS: OSI was increased in patients with PHPT when compared to normal controls, whereas TAC was lower in PHPT. The levels of CER, MnSOD, GR, SH groups and MDA were significantly decreased in PHPT. The levels of serum LHP, catalase and SOD were significantly higher in patients with PHPT than in healthy patients. The erythrocyte CAT activity and GST were significantly increased in patients after parathyroidectomy. The erythrocyte GR and GPx were up-regulated postoperatively, whereas SOD activity decreased. CONCLUSIONS: In PHPT there are several alterations in the balance between the production of reactive oxygen species and antioxidant defense system.

Oxidative stress and angiogenesis in primary hyperparathyroidism.

BACKGROUND: The inappropriate elevation of parathormone (PTH), which regulates the process of angiogenesis in parathyroid tissue, causes the changes of activity of enzymes responsible for the removal of free radicals. Parathyroidectomy (PTX) in patients with primary hyperparathyroidism (PHPT) lowers the level of PTH and leads to the reduction of risk of cardiovascular and all-cause mortality by normalization of the antioxidant status. Therefore, the aims of the study were to assess the activity of antioxidant enzymes and free radical reaction products in patients after parathyroidectomy, and to evaluate the correlation between the systemic oxidative stress and angiogenic parameters. MATERIALS AND METHODS: Patients with PHPT treated surgically were enrolled into the study. Total antioxidant capacity (TAC), total oxidative status (TOS), oxidative stress index (OSI), superoxide dismutase (SOD), ceruloplasmin (CER), lipid hydroperoxides (LHP) and malondialdehyde (MDA) were measured before and after parathyroidectomy. The immunohistological expression of angiogenic factors in parathyroid specimens was assessed by the BrightVision method from ImmunoLogic using murine monoclonal anti-human: anti-VEGF, anti-CD31 and anti-CD106 antibodies. RESULTS: The significant increase of TAC, CER, reduction of TOS, MDA, SOD, especially for cytoplasmic form, and significant decrease of OSI, LHP were observed after PTX. There was no significant correlation between changes of oxidative stress markers and angiogenic parameters: VEGF, CD-31, CD-106 in parathyroid tissue. The correlation level was low and medium. CONCLUSIONS: Parathyroidectomy causes down-regulation of lipid peroxidation processes and leads to reduction of oxidative stress in patients with PHPT. The decrease in the OSI is the results of down-regulation of oxidative stress in the postoperative period. The change of the antioxidant status has no impact on angiogenesis processes in parathyroid tissue.

Expression of TRAIL and Fas in Primary Hyperparathyroidism.

AIM: Differentiating between parathyroid lesions is still difficult and ambiguous. In cases of primary hyperparathyroidism, appropriate and prompt diagnosis is of great importance for effective treatment and follow-up. A great amount of mechanisms contribute to the pathogenesis of primary hyperparathyroidism, such as disturbance in balance between pro- and anti-apoptotic factors. Therefore, we examined whether immunohistochemical expression of apoptotic factors, TNF-related apoptosis-inducing ligand (TRAIL) and Fas, could have clinical utility as a marker of proliferative lesions of parathyroid gland. MATERIALS AND METHODS: Parathyroid specimens of 58 consecutive patients who had undertaken surgery due to primary hyperparathyroidism were incubated with purified mouse monoclonal antihuman antibodies: anti-TRAIL and anti-Fas. Staining was considered positive when at least 5% of the cells showed immunoreactivity. RESULTS: The percentage of cells which were positively stained for TRAIL in parathyroid hyperplasia was 9.65%, in parathyroid adenoma 8.31%, and in normal controls 2.24%. Immunoreactivity for TRAIL was detected in 91.89% of parathyroid hyperplasias, 85.71% of parathyroid adenomas, and none in healthy glands. The percentage of cells with a positive reaction to Fas in parathyroid hyperplasia was 8.92%, in parathyroid adenoma 8.09%, and in normal tissue 1.9%. The expression of Fas was found in 94.59% of parathyroid hyperplasias, 90.48% of parathyroid adenomas, and none in healthy glands. CONCLUSIONS: In our study, hyperplasias demonstrated the highest expression of TRAIL and Fas, whereas in adenomas it was increased compared to normal tissue, but lower than in hyperplasias. These factors could be an additive tool in the differential diagnosis of parathyroid lesions.

Molecular profiling in primary hyperparathyroidism.

BACKGROUND: Primary hyperparathyroidism (HPT) is one of the most common endocrine disorders, defined by hypersecretion of parathormone. Primary HPT can be caused by adenoma, hyperplasia, and carcinoma. A great amount of mechanisms contribute to the pathogenesis of this disease, such as genetic predispositions because of the germline-inactivating mutations in the multiple endocrine neoplasia type 1 (MEN1) and HRPT2 tumor suppressor genes. Somatic mutations in these genes were found also in sporadic parathyroid neoplasias. Cell cycle regulators, growth factors, apoptosis-inducing ligands, death receptors, and other transmitter substances have also been implicated in the etiology of primary HPT. Parathyroid carcinoma is often misdiagnosed as parathyroid adenoma and long-term survival is conditioned by the extent of the primary surgical resection, therefore, of great interest is the discovery of definitive diagnostic markers for carcinoma. This article presents current state of knowledge of the molecular pathogenesis of primary HPT.