Lipid Status and Predisposing Genes in Patients with Diabetes Mellitus Type 1 from Various Ethnic Groups

Oxidative Stress: Pathogenetic Role in Diabetes Mellitus and Its Complications and Therapeutic Approaches to Correction

The review presents modern views about the role of oxidative stress reactions in the pathogenesis of types 1 and 2 diabetes mellitus and their complications based on the analysis of experimental and clinical studies. The sources of increased ROS generation in diabetes are specified, including the main pathways of altered glucose metabolism, oxidative damage to pancreatic β-cells, and endothelial dysfunction. The relationship between oxidative stress, carbonyl stress, and inflammation is described. The significance of oxidative stress reactions associated with hyperglycemia is considered in the context of the “metabolic memory” phenomenon. The results of our studies demonstrated significant ethnic and age-related variability of the LPO—antioxidant defense system parameters in patients with diabetes mellitus, which should be considered during complex therapy of the disease. Numerous studies of the effectiveness of antioxidants in diabetes mellitus of both types convincingly proved that antioxidants should be a part of the therapeutic process. Modern therapeutic strategies in the treatment of diabetes mellitus are aimed at developing new methods of personalized antioxidant therapy, including ROS sources targeting combined with new ways of antioxidant delivery.

Lipid peroxidation processes in men with type 1 diabetes mellitus following α-lipoic acid treatment

<abstract> <p>In various pathological conditions such as diabetes mellitus, the cellular redox balance can be disturbed and these alterations may persist even after blood glucose levels have returned to normal. Antioxidant therapies, including α-lipoic acid, are widely used to treat various systemic diseases including diabetes mellitus. The aim of this study was to measure the lipid metabolism parameters, as well as the activity of lipid peroxidation and antioxidant defense reactions, in men with type 1 diabetes mellitus (T1DM) during treatment with α-lipoic acid. Twenty-four reproductive-age T1DM males with an unsatisfactory glycemic profile were examined. Twenty-eight practically healthy men of similar age were used as the control group. Spectrophotometric, fluorometric, and enzyme-linked immunoassay methods were used. T1DM was characterized by increased values of lipid metabolism components, including total cholesterol, triacylglycerides (TG), and very-low-density lipoproteins (VLDL). In the lipid peroxidation system, increased levels of the primary products (conjugated dienes), secondary products (thiobarbituric acid reactants), and final products (Schiff bases) were observed in T1DM patients compared to the control group. Retinol values were also increased. After treatment, there was a decrease in TG, VLDL, and Schiff bases levels and an increase in the retinol level compared to before treatment. These results expand our understanding of the pathogenetic mechanisms of T1DM and suggest that α-LA treatment may be beneficial for type 1 diabetics.</p> </abstract>

EVALUATION OF LIPID PROFILE COMPONENTS IN FOREIGN STUDENTS STUDYING AT THE IRKUTSK STATE MEDICAL UNIVERSITY

Background. A socially significant order for the training of foreign specialists, including the promotion of Russian education on the international market, certainly requires the organization of the process of students’ adaptation to the educational and information environment of the university. Particular attention deserves the components of the lipid profile, which are part of the overall adaptation syndrome.

Aim: to study the features of the lipid profile in foreign students studying at the Irkutsk State Medical University.

Methods. In total, 100 students of the medical profile of the Irkutsk State Medical University were enrolled in full-time study: 58 students (36 males and 22 females) were students of Russian nationality and 42 students (32 males and 11 females) – Indian students. Levels of lipid status indicators were determined with the help of Cormay kits on the automatic analyzer BTS-330 using the photometry method.

Results. Hindu young men had statistically significantly higher values of triacylglycerols, very low-density lipoproteins and lower levels of high-density lipoproteins in comparison with young Russians. In the groups of girls of Indian origin, the changes concerned increased levels of triacylglycerols and very low-density lipoproteins in comparison with Russians. Gender differences were found only among Russian students – in the form of increased values of cholesterol and low-density lipoproteins in the group of girls compared to boys.

Conclusion. The established functional changes in lipid metabolism in foreign students characterize the stress of the adaptive resources of the body, which, probably, can be due to the irrationality of nutrition.

N-nitrosamines induced infertility and hepatotoxicity in male rabbits

N-nitrosamines are widely spread environmental pollutants of well-known toxicity and carcinogenicity in various animal species. These compounds are metabolically activated by cytochrome P450 system predominantly in the liver and in other tissues into more active metabolites leading to generation of both alkylating agents that alkylate DNA and reactive oxygen species. In the current study, we investigated the influence of four types of N-nitrosamines that are commonly present in the environment [methyethylnitrosamine, (MEN), diethylnitrosamine (DEN), diphenylnitroasamine (DPN) and dimethylnitrosamine (DMN)] on both livers and testes of male rabbits through assessment of 17 β-hydroxysteroid dehydrogenase (17 β-HSD) activity. The protein expression of the three cytochrome P450s (CYP11A1, CYP19A1, and CYP21A2) is involved in the steroidogenesis. The levels of testosterone (T) and estradiol (E2) were also determined in the plasma of N-nitrosamines-treated rabbits after one, four-, eight- and twelve weeks of treatment of male New Zealand rabbits with an oral dose of 0.5 mg/kg B.W/day of each compound. In addition, activities of glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT) and levels of free radicals measured as thiobarbituric acid reactive substances (TBARS), and reduced glutathione (GSH) level were quantified in both livers and testes. The present study showed that levels of free radicals (TBARS) were markedly increased, whereas GSH levels were depleted in the tissues of both livers and testes after treatment of rabbits with any of N-nitrosamines. In addition, all tested N-nitrosamines inhibited the activities of antioxidant enzyme activities (GR, GST, SOD, and CAT) in hepatic and testicular tissues of rabbits after 12 weeks of treatment. Histopathological examination showed that N-nitrosamines caused lymphocytic infiltration with vascular degeneration and necrosis, congestion of central vein with RBCs hemolysis, dilated sinusoids, as well as fibrosis around portal areas were seen in hepatic tissues. In the testes, histopathological examination displayed disorganized seminiferous tubules with degeneration of germinal epithelium and Sertoli cells. Also, spermatogenic cells had pyknotic nuclei and others were detached from basement membranes of seminiferous tubules, edema was seen between seminiferous tubules. Moreover, the present data showed that MEN and DEN down-regulated the protein expression of both CYP19A1 and 21A2 in both livers and testes of male rabbits. In addition, both MEN and DEN decreased levels of testosterone and estradiol in plasma of treated rabbits. On the one hand, DMN and DPN markedly up-regulated the protein expression of CYP19A1 in both hepatic and testicular tissues of treated rabbits. These compounds potentially increased estradiol and decreased testosterone levels. On the other hand, no correlation was found between the expression of CYP11A1 and levels of both testosterone and estradiol. It is concluded that most of tested N-nitrosamines induce different changes, which could be a new mechanism of infertility due to exposure to N-nitrosamines from different environmental sources.