Oxidative stress in proliferative lesions of parathyroid gland

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.

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.

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.

In PHPT there are several alterations in the balance between the production of reactive oxygen species and antioxidant defense system.