Leptin-reactive antibodies are distinctly correlated with body composition parameters and metabolic risk indexes in children and adolescents

Leptin/Ghrelin Axis and Antibodies Reactive to Both Hormones in Relation to Metabolic Syndrome Components in Mexican Children

Background: Metabolic syndrome (MetS) in children is a rising health issue that is strongly associated with cardiovascular diseases and type 2 diabetes mellitus development. Low-affinity antibodies reactive to leptin and ghrelin are suggested to regulate hormone stability and function; nevertheless, the role of the leptin/ghrelin axis and antibodies reactive to both hormones in relation to MetS or its components in the pediatric population remains unknown. Methods: Fifty-eight children (7-12 years) were included and categorized according to the presence of one or more criteria for the diagnosis of MetS or according to body mass index. Body composition, biochemical variables, and metabolic risk indexes were determined. Antibodies reactive to leptin and ghrelin were quantified by an in-house enzyme-linked immunosorbent assay test. Ratios of leptin/ghrelin hormones and anti-leptin/anti-ghrelin immune complexes were obtained. Results: The biochemical variables glucose (P = 0.0009), insulin (P = 0.0001), leptin (P = 0.0036), HOMA-IR (homeostatic model assessment for insulin resistance) (P < 0.0001), and plasma atherogenic index (P < 0.0001) were significantly higher in children with two or three components of MetS (MetS 2-3) in comparison to children with none or one component (MetS 0-1). Ratios of leptin/ghrelin (P = 0.0307) and anti-leptin/anti-ghrelin immune complexes (P = 0.0338) were higher in MetS 2-3 group versus MetS 0-1 group. In MetS 2-3 group, both insulin (r = 0.4361, P = 0.0293) and HOMA-IR (r = 0.4761, P = 0.0161) were positively correlated with the leptin/ghrelin hormone ratio. Conclusions: The higher leptin/ghrelin hormone ratio scores observed in MetS 2-3 group, along with their correlation with insulin levels and HOMA-IR, highlight the role of leptin and ghrelin on insulin sensitivity and metabolic regulation. An increased ratio of anti-leptin/anti-ghrelin immune complexes suggests affinity changes in these antibodies that may lead to alterations in hormone function.

Antibodies Reactive to Leptin in Adults with Type 2 Diabetes and Its Relationship with Clinical, Metabolic and Cardiovascular Risk Parameters

BACKGROUND AND AIMS

Patients with obesity and type 2 diabetes (T2D) have shown alterations in the affinity of IgG anti-leptin antibodies which are possibly related to metabolic alterations. In the present exploratory study, we analyzed serum samples from adults with T2D classified by body mass index (BMI) and evaluated the relationship of IgG anti-leptin antibodies with body composition, metabolic and cardiovascular risk parameters.

METHODS

Serum IgG anti-leptin antibodies (total, free and immune complexes fractions) were measured by in-house ELISA. Body composition, metabolic biomarkers (glucose, glycated hemoglobin, lipid profile, insulin, leptin) and cardiometabolic risk indexes (AIP, HOMA-IR, HOMA-ß) were evaluated in one hundred T2D patients.

RESULTS

Patients with T2D and obesity presented a decrease in the percentage of IgG anti-leptin immune complexes compared to patients with T2D and overweight (p < 0.0053). Negative correlations of IgG anti-leptin immune complexes with triglycerides (TG) (r=-0.412, p = 0.023) and VLDL-C (r=-0.611, p = 0.017) were found in normal weight T2D patients. Free IgG anti-leptin antibodies correlated positively with TC (r = 0.390, p = 0.032) and LDL-C (r = 0.458, p = 0.011) in overweight individuals with T2D. Finally, total IgG anti-leptin antibodies correlated positively with leptin hormone levels (r = 0.409, p = 0.024) and negatively with HOMA-IR (r =-0.459, p = 0.012) in T2D patients with obesity.

CONCLUSIONS

The decrease of IgG anti-leptin immune complexes observed in patients with T2D and obesity suggests a reduction in antibody affinity to the hormone that may impact its transport and signaling, lipid, lipoprotein and insulin metabolism.