Background

Adolescents with obesity represent a serious problem. Inflammation and immune dysregulation associated with obesity contribute to associated health risks. This study aimed to investigate immune cell proportions and their acute responses to lipopolysaccharide (LPS) stimulation from samples collected at the time of bariatric surgery. Adipocyte diameter was evaluated as well.

Methods

Peripheral blood mononuclear cells were isolated from adolescents with a BMI > 95th PC, and controls. Stimulation of isolated PBMCs with 1 µg LPS, and assessment of lineage-specific activation through CD69 expression at 0, 2, and 6 hours was performed. Adipocytes were analyzed for mean area.

Results

Thirteen samples, 9 individuals with obesity and 4 controls, were analyzed. Adolescents with obesity exhibited a mean BMI of 46.33 kg/m2 (SD +/- 12.29 kg/m2 - mean Z score of 2.6), Adipocyte diameter was greater in samples from adolescents with obesity (mean area of 4874 µm vs 555.3 µm, P<0.05) (Figure 1). Following stimulation of PBMCs, CD69+ activation, measured by mean fluorescence intensity, on the surface of B cells and CD4 T cells after the 6 hours was higher in the population with obesity. (Mean Diff. -959.7, with a 95% CI of diff -1640 to -279.5, P <0.05) (Figure 2).

Conclusions

Our cohort exhibited higher adipocyte mean area suggesting physiologic adaption. There was a heightened response from B cells and CD4 cells upon stimulation. This study sheds light on early abnormalities in the pediatric population, indicating an exaggerated immune response that may lead to serious diseases. Limitations: Number of samples.