Lipid peroxidation as a predictive biomarker of the early stage of cancer.

Prostate cancer continues to be a major cause of morbidity and mortality in men around the world. The data concerning the antioxidant status and the degree of lipid peroxidation at the moment of the initiation of cancer is limited. The aim of this research is to assess the effect of selected minerals (zinc, selenium, iron, copper and calcium) on the growth of the neoplastic process and the concentrations of selected biomarkers of the oxidative damage in rats with implanted prostate cancer cells. It was found that the diet supplementation with selected minerals (zinc, selenium, iron, copper and calcium) affect the occurrence of prostate tumor growth in the examined rats. The intraperitoneal implantation of prostate cancer cells resulted in the occurrence of prostatic adenoma in 71% of the examined rats. In the rats that were additionally supplemented with selenium and with copper, the cancer cell aggregates constituted, respectively, 25% and 38% of the cases. As a result of implantation of cancer cells, the level of biomarkers of lipid peroxidation increased both in the urine and in tissues of the examined animals (rat group without supplementation). No relationship was found between the process of lipid peroxidation due to the supplementation with selenium and copper, and the lower incidence of cancer and the induction of apoptosis. The reduced activity of antioxidative enzymes (catalase, superoxide dismutase and glutathione peroxidase) creates favorable conditions for the formation of cancer cell aggregates, which was shown in the rats whose diet was supplemented with iron. In summary, we conclude that lipid peroxidation represents a fruitful approach to early stage cancer prevention. Supplementation of rats with trace elements correlated with the risk of developing cancer, but the mechanisms of this action is complicated and dose-dependent.

Effect of zinc, copper and resveratrol supplementation on the urinary level of 15-hydroxyeicosatetraenoic acid at the early stage of breast cancer in rats.

The aim of the present study was to assess the effect of zinc and copper, separately or in combination with resveratrol, on the concentration of 15-hydroxyeicosatetraenoic acid (15-HETE) in urine of rats with mammary cancer (adenocarcinoma) induced with 7,12- dimethyl-1,2-benz[a]anthracene (+ DMBA). The research focused on the kinetics of alterations in urinary 15-HETE at the early stage of carcinogenesis, as well as on the influence of dietary factors on the process. The content of 15-hydroxyeicosatetraenoic acid in the rats' urine was determined by enzyme-linked immunosorbent assay (ELISA). The 15-HETE level was standardized by conversion to the creatinine level. Regardless of the diet (standard, Zn, Zn+resveratrol, Cu, Cu+resveratrol), DMBA-induced breast carcinogenesis was not inhibited. On the contrary, in the Zn+resveratrol supplemented group, tumorigenesis developed at a considerably faster rate. It was found that the supplementation of the rats' diet with zinc only or zinc plus resveratrol resulted in a reduction of the 15-HETE level in urine of rats with mammry cancer (+ DMBA) as compared with control rats (- DMBA). A statistically lower concentration of 15-HETE was found in urine of rats supplemented with zinc or copper with resveratrol when compared with the animals that received only zinc or copper (p=0.02; p=0.0001). Summing up the obtained results, it can be concluded that the level of 15-HETE in urine of the examined animals depended on the applied supplementation.

[Balance of magnesium and iron and their content in tissues and body fluids of rats after supplementation with magnesium carbonate]. / Bilans magnezu i zelaza oraz ich zawartosc w narzadach i plynach ustrojowych szczurów poddanych suplementacji weglanem magnezu.

Effect of magnesium on iron and magnesium metabolism in rats were investigated. 96 male Wistar rats were divided into four groups received 2.5; 5.0 and 10.0 mg magnesium daily per kg of body weight--dissolved in 2%--solution of arabic gum (tests groups) or clear 2%--solution of arabic gum (test group) for 4 weeks and the next 4 weeks without supplements. Iron concentrations increased in the brain and kidney of the experimental rats, but decreased in the spleen, intestine and liver (2 and 4 weeks only) also in the heart and femur (only 8 week). Percentage of iron retention decreased during the whole experiment. Magnesium concentrations increased in the spleen, liver and intestine of rats. It was shown that at 8 weeks of experiment the magnesium level of heart and femur decreased (only groups received 2.5 mg and 5.0 mg Mg/kg b.w./24 h), but in group received 10.0 mg Mg/kg b.w./24 h increased for all experiment. The apparent retention of magnesium increased in start of the experiment. This results show that oral magnesium supplementation disturbs metabolism of these elements, especially balance of iron.