Effect of leptin and adiponectin on the expression of cytokine genes IL-1β, IL-6 AND TNFα in lymphocytes

Metabolic syndrome (MS) is one of the world’s topical health problems. Large-scale epidemiological studies on the prevalence of MS in the world have not been conducted, but according to different authors, depending on the region of residence, the composition of the study population and the diagnostic criteria used, the incidence of MS is at least 10%, and according to estimates of the International Diabetes Federation IDF – up to 25% of the adult population. The metabolic changes in MS are explained by a disturbance in the balance of mediators synthesized by adipose tissue (adiponectin, leptin, resistin, visfatin, vaspin and others); MS is also considered as a subclinical chronic inflammatory process characterized by excessive synthesis of proinflammatory and deficiency of anti-inflammatory cytokines. According to modern ideas, changes in the cellular and humoral immunity in MS are largely due to the imbalance of adipokines: leptin and adiponectin. Increased functional activity of immune cells, including lymphocytes, leads to changes in cytokine gene expression. In the present work, we studied in vitro the expression of IL-1â, IL-6 and TNFá genes in peripheral blood lymphocytes under the influence of adipokines at concentrations characteristic of MS. As a result, differential effects of adipokines on lymphocytes of MS patients and conditionally healthy individuals were found. In conditionally healthy individuals, incubation of lymphocytes with adipokines leptin, adiponectin and their combination, as well as in the presence of physiological solution causes an increase in IL-6 gene expression. The most noticeable effect was observed when cultured with adiponectin. Thus, in norm, with a decrease in the physiological concentration of adiponectin, the expression of IL-6 in lymphocytes increases, indicating insufficient realization of the anti-inflammatory effect of adiponectin. In MS, IL-6 gene expression increases in lymphocytes isolated from peripheral blood in vitro after incubation with adiponectin, a combination of adiponectin and leptin, as well as in the presence of physiological solution. No changes in IL-6 gene expression under the effect of high concentration of leptin were detected.

Probably, our results reflect the phenomenon of lymphocyte resistance to leptin action in MS, as under its influence there is not activation of lymphocytes characteristic in vivo, but on the contrary, decrease of activated subpopulations, also there is no change in IL-6 gene expression. Thus, adipokines in concentrations characteristic of metabolic syndrome influence the functional activity of peripheral blood lymphocytes.