Immunohistochemical assessment of mitochondrial superoxide dismutase (MnSOD) in colorectal premalignant and malignant lesions

Introduction: It is generally accepted that mitochondria are a primary source of intracellular reactive oxygen species (ROS). Under physiological circumstances they are permanently formed as by-products of aerobic metabolism in the mitochondria. To counter the harmful effect of ROS, cells possess an antioxidant defence system to detoxify ROS and avert them from accumulation at high concentrations. Mitochondria-located manganese superoxide dismutase (MnSOD, SOD2) successfully converts superoxide to the less reactive hydrogen peroxide (H2O2). To the best of our knowledge, there are no available data regarding immunohistochemical expression of MnSOD in colorectal neoplastic tissues. Aim: To investigate the immunohistochemical expression status of MnSOD in colorectal premalignant and malignant lesions. Material and methods: This study was performed on resected specimens obtained from 126 patients who had undergone surgical resection for primary sporadic colorectal cancer, and from 114 patients who had undergone colonoscopy at the Municipal Hospital in Jaworzno (Poland). Paraffin-embedded, 4-mu m-thick tissue sections were stained for rabbit polyclonal anti SOD2 antibody obtained from GeneTex (clone TF9-10-H10 from America Diagnostica). Results: Results of our study demonstrated that the development of colorectal cancer is connected with increased expression of MnSOD both in adenoma and adenocarcinoma stages. Samples of adenocarcinoma with G(2) and G(3) grade showed significantly higher levels of immunohistochemical expression of this antioxidant enzyme. Moreover, patients with the presence of lymphovascular invasion and higher degree of regional lymph node status have been also characterised by higher levels of MnSOD expression. The samples of adenoma have been characterised by higher levels of MnSOD expression in comparison to normal mucosa as well. Interestingly, there was no significant correlation between expression and histological type of adenoma. Conclusions: Development of colorectal cancer is connected with increased expression of MnSOD both in adenoma and adenocarcinoma stages. Keyword

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

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

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