1Universidad de Guadalajara, Zapotlán el Grande, México, 2Laboratorio de Biomedicina y Biotecnología para la Salud, Zapotlán el Grande, México, 3Unidad Especializada en Investigación, Desarrollo e Innovación en Medicina Genómica, CENyT, Universidad Autónoma de Nayarit, Nayarit, México.
Type II diabetes mellitus (T2DM) is characterized by alterations in the metabolism of carbohydrates, fat and proteins; which are related to deficiencies over the action or secretion of insulin. Recent studies identified the presence of antibodies directed against neuropetides and hormones that regulate appetite and metabolism, including antibodies against leptin. As of today, the presence of autoantibodies against leptin in adults with T2DM remains unknown, hence the present work set the objective of analyzing anti-leptin antibodies serum levels in adults with T2DM, as well as determining its relationship with body composition, metabolic profile, and cardiovascular risk factors. One hundred serum samples from adults aged 57.12 ± 11.64 years were included and categorized in: normal-weight, overweight and obesity. Anthropometric, biochemical parameters such as cholesterol, glucose, Hb1Ac, insulin, leptin, HDL-C, LDL-C, VLDL-C, triglycerides were measured. Also anthropometric and metabolic indexes such as BMI, waist circumference, body fat percentage and HOMA-IR were evaluated. In-house ELISA test was performed for detection of anti-leptin serum levels (IgG isotype) in their free and total fractions, plus the percentage of immune complexes. Free anti-leptin IgG autoantibodies serum levels were higher in obese than in normal-weight TDM2 patients (p <0.001). Furthermore, the percentage of immune complexes was significantly lower in obese patients (p <0.01) than in overweight. After evaluating correlation between anti-leptin immune complexes and biochemical parameters, negative correlations were observed in subjects of the normal weight group with: TG (r = -0.4126, p = 0.0235) and VLDL-c (r = -0.6118, p = 0.0174). In obese subjects, total anti-leptin antibodies showed a positive correlation with serum leptin (r = 0.4096, p = 0.0246) and a negative correlation with HOMA-IR (r = -0.4506, p = 0.0121). Overall, this research proves presence of IgG isotype anti-leptin antibodies in normal weight, overweight and obese subjects with T2DM. Furthermore, it is suggested that the production of these antibodies is influenced by body composition and leptin secretion, highlighting an adaptive mechanism.
Keywords: anti-leptin autoantibodies, diabetes mellitus tipe 2, cardiovascular risk, adultos