Changes of endothelial function and oxidant status in insulin resistance and obesity under the conditions of iodine deficiency

Abstract

Background. The topicality of the theme is due to the significant prevalence of cardiovascular diseases and an increase in costs for medical care, the high risk of disability, which characterizes the medical and social component of the problem. Pathological changes can be a manifestation not only of a cardiovascular disorder, but also develop as a result of other diseases, including diabetes mellitus, obesity, and thyroid pathology. One of the main mechanisms of morbidity and mortality is macrovascular complications that can occur in endothelial dysfunction and oxidative stress. The purpose of the research is to study the peculiarities of changes in the parame­ters of the endothelial system and oxidant status in animals with insulin resistance and obesity under conditions of adequate iodine supply and iodine deficiency. Materials and methods. Study included 75 sexually mature rats having received a high-carbohydrate, high-fat diet under conditions of adequate and limited iodine supply, followed by analysis of markers of carbohydrate metabolism, thyroid status, indices of endothelial function, lipid peroxidation and antioxidant protection. Results. The development of insulin resistance and obesity in a diet loaded with fructose and fats is accompanied by the development of endothelial dysfunction: in the blood serum, the level of endothelin-1 increases and inducible NO-synthase (iNO-synthase) is activated, in the myocardium, the activity of iNO-synthase increases compared to the data in animals who received a standard diet. The development of oxidative stress in experimental animals characterizes an increase in the content of diene conjugates and thiobarbituric acid-reactive substances in blood serum and myocardium against the background of inhibition of serum antioxidant enzymes (catalase, superoxide dismutase, ceruloplasmin, glutathione peroxidase, glutathione reductase). The degree of endothelial dysfunction and the intensity of lipoperoxidation increase with hypothyroid dysfunction against the background of iodine deficiency. Conclusions. Metabolic disorders under the conditions of insulin resistance and obesity are characterized by the development of endothelial dysfunction and oxidative stress, which are the predictors of the development of cardiovascular risks. Their intensity depends on carbohydrate and thyroid homeostasis.

Keywords

• cardiovascular system
• insulin resistance
• obesity
• thyroid homeostasis
• endothelial dysfunction
• pro-/antioxidant system