Endocrine Abstracts

Obesity of varying severities can be seen in the vast majority of patients with type 2 diabetes mellitus (DM2). Oxidative stress is considered as a key pathogenetic link in the formation of metabolic disorders in obesity. The work was initiated to assess intensity of oxidative stress in obese patients with DM2.

Materials and methods

The patients were divided into 3 groups. Patients with DM2 and BMI > 30 kg/m² were included into the 1^st group. The 2^nd group consisted of obese non-diabetic persons with BMI > 30 kg/m². Apparently healthy persons with BMI < 30 kg/m² were included into the 3^rd group. Concentrations of malondialdehyde (MDA), a lipid peroxidation (LPO) end product, were used to assess LPO in blood of patients with diabetes mellitus. Activity of catalase, an antioxidant system (AOS) enzyme, was used to assess AOS. Serum concentrations of TNF-α, a proinflammatory cytokine, were measured by EIA with the test systems (Vector-Best, Russian Federation).

Results

As compared to apparently healthy persons, HOMA-IR index was found higher in obese non-diabetics by 1.8 times (P < 0.05) and in obese patients with DM2 by 2.6 times (P < 0.01). Lipid profile parameters typical of atherogenic disorders, to name elevated triglycerides, as well as LDL, VLDL and cholesterol, were found in obese patients in these two groups. Our study on blood LPO and AOS demonstrated significant impairments in peroxidation and weakening of antioxidant mechanisms both in obese diabetics and non-diabetics. As compared to apparently healthy persons, serum concentrations of MDA, a toxic product of lipid peroxidation, were observed higher in obese diabetics (by 40.3%, P < 0.01) and obese non-diabetics (by 14.3%, P < 0.05). In these patients, blood catalase activity was found declined to be the evidence for reduction of AOS activity. Of interest, as compared to apparently healthy persons, serum TNF-α levels were found significantly higher by 5 times (P < 0.01) in obese diabetics and by 4.5 times (P < 0.05) in obese non-diabetics, demonstrating direct correlation to HOMA-IR index.

Conclusion

Associated with obesity, insulin resistance and diabetes mellitus facilitate intensification of oxidative stress in the organism. Significant elevations in serum TNF-α concentrations is the risk factor for insulin resistance and DM2.