**9. Conclusion**

decrease in glycemia did not reach statistical significance. An important advantage in our study was that, despite the common belief about neutral effect that DPP-4 inhibitors have on weight, we demonstrated that with the addition of Sitagliptin to metformin, there was a more marked weight loss and decrease of BMI and visceral fat depot, compared to the group of patients on metformin monotherapy. What was a "pure" contribution of DPP-4 inhibitor + metformin combination, and what was due to lifestyle changes in both groups could not be determined in this work, therefore, further prospective studies including quantitative calculation of energy inputs are required. The study of adipokine status, specifically leptin and adiponectin, was of particular interest. The main function of leptin is forming a communication pathway link between adipocytes and the brain [19]. Leptin secretion positively correlates with the amount of adipose tissue, which we also demonstrated in our work. In addition to the anorectic effect in the adjustment of eating behavior, leptin also stimulates energy intake. During increased energy intake exceeding the body's requirements, the leptin level increases, which prevents further food consumption and increases energy expenditure, and that leads to negative energy balance and rebalancing of energy. Most obese patients have high leptin levels, but this does not lead to weight loss, which confirms the fact that obese patients may develop resistance to leptin. Leptin's effect disorder in obesity can be a leading factor in the development of insulin resistance and fat and glucose metabolism disorder. In our work, on a background of combined Sitagliptin and metformin therapy, the leptin level was reduced by 30.47% and in the metformin monotherapy group by 5.41%. We associate decrease in leptin level with weight loss and a decrease in the

In both study groups, the initial adiponectin levels were lower than reference values. After 24 weeks of therapy, adiponectin content in blood increased by 27.06% in the group receiving Sitagliptin and metformin combination, and by 7.16% in the group receiving metformin monotherapy. Adiponectin with its effect on the reduction of insulin resistance, which is characteristic of patients with T2D and obesity, and also its anti-inflammatory, antidiabetic and antisclerotic effects make it an additional therapeutic target. In our study, an increase of adiponectin is most likely associated with a decrease of body weight and VFA, according to the data of the correlation analysis. However, there are publications which make it known that GLP-1 promotes an increase in adiponectin level [20, 21], the Sitagliptin therapy was followed

Correlational analysis demonstrated correlation of glycemic control in T2D obese patients with reducing visceral fat amount and with recovery of secretion of adipose tissue hormones. In addition, the study showed a significant improvement in the functional activity of pancreatic β-cells against combined Sitagliptin and metformin therapy, which was confirmed by an increase in the HOMA-β index, a decrease in the ratio of proinsulin/insulin, in contrast to metformin monotherapy, where the change in these indices did not reach statistical significance. A possible mechanism for improving the function of β-cells can be a decrease in lipotoxicity, against a background of a decrease in the level of TG inhibiting

amount of fat.

66 Diabetes and Its Complications

β-cell function.

by increase in adiponectin level [22, 23].

Our study demonstrated the important role of correction of fat metabolism disorders in improving glycemic control in patients with diabetes and obesity. Regression of visceral fat according to the MRI results was accompanied by the recovery of levels of adipokine hormones, which led to an improvement in the parameters of carbohydrate and fat metabolism. Contrary to common belief, we consider Sitagliptin as a drug that promotes weight loss. The chapter demonstrates that ultimately it is the reduction of the visceral depot that plays a key role in the correction of carbohydrate metabolism disorders. The parameters of the lipid profile and glycemic control are significantly improved as the pathogenetic effect on patient's body weight as well as on the structure of its adipose tissue. Recovery of such indicators as HOMA-IR and HOMA-β proves the possibility of disease management by correcting disorders of fat metabolism in patients with T2D and obesity in the early stages.
