Differences between antioxidant defense parameters and specific trace element concentrations in healthy, benign, and malignant brain tissues.

There are only a few reports examining the impact of oxidative stress in patients with benign and malignant brain tumors. In this study we investigated whether there are changes in antioxidant system (AOS) parameters and key trace elements between control, benign and malignant brain tissues. The study also aimed to examine correlations between the analyzed parameters. The study enrolled both types of brain tumors, benign tumors (BT) and malignant tumors (MT). The results were compared with control tissue (CT) without tumor infiltration collected from patients with BT. The following antioxidant parameters were determined: activities of total, manganese-containing, and copper/zinc-containing superoxide dismutase (TotSOD, MnSOD and CuZnSOD), activities of catalase, glutathione peroxidase, glutathione S-transferase, glutathione reductase and acetylcholine esterase (AChE), the concentrations of glutathione and sulfhydryl groups and of manganese (Mn), copper (Cu), zinc (Zn), and selenium (Se). BT and MT had altered activities/levels of multiple AOS parameters as compared to CT, indicating that tumor cells had an altered cell metabolism and changes in AOS represent adaptive response to increased oxidative stress. Low MnSOD and AChE and high GST activities were significant for distinguishing between MT and CT. Malignant tissue was also characterized by lower Mn and Cu concentrations relative to CT and BT. Principal Component Analysis clearly discriminated BT from CT and MT (PC1, 66.97%), while PC2 clearly discriminated CT from BT and MT (33.03%). Most correlative relationships were associated with Se in the BT group and Cu in the MT group. The results of this study reveal differences between the AOS parameters and the essential trace elements between the analyzed groups. The observed dysregulations show that oxidative stress could have an important role in disrupting brain homeostasis and its presence in the pathogenesis of benign and malignant brain tumors.

Cadmium as main endocrine disruptor in papillary thyroid carcinoma and the significance of Cd/Se ratio for thyroid tissue pathophysiology.

BACKGROUND: The etiology of papillary thyroid carcinoma (PTC) is unknown and some literature data support the hypothesis that heavy metals, as endocrine disrupters, could play a major role in the pathogenesis of thyroid cancer. This study aimed to estimate the content of selected toxic and essential trace metals (Mn, Co, Ni, Cu, Zn, As, Se, Cd, Pb, Th, and U), as well as the selected ratio's (Cu/Zn and Cd/Se) in the malignant thyroid tissues according to sex, age, smoking habits, familial history of any thyroid disease, pathohistological (PH) types of PTC, tumor size, the existence of a thyroid capsular invasion, intrathyroid tumor dissemination, retrosternal thyroid growth, and TNM progress of PTC. METHODS: The study included 66 patients with PTC (women/men ratio = 46/20, mean age: 54 ± 14 years). A comparative analysis was made by collecting the healthy thyroid tissues (HTTs) of the same patients, making the total number of samples 132. All trace metals were quantified by inductively coupled plasma-mass spectrometry (ICP-MS). RESULTS: Metals that significantly separated papillary thyroid tissues (PTTs) from the HTTs were Cd, U and Se (p < 0.05). The obtained negative correlation between Cd and Se in the PTTs could explain extrusion of essential Se caused by increased content of Cd. Only Cd had an influence on the retrosternal thyroid growth, while the essential metals (Mn, Co, and Zn) had an influence on thyroid capsular invasion. CONCLUSION: It was found that Cd act as the main endocrine disrupter, which could highlight its role in the etiology of PTC. Considering that the Cd/Se ratio significantly separated two studied groups and had an influence on the retrosternal thyroid growth, its altered content could contribute to the better understanding of the molecular basis for pathophysiological changes in the PTC.