Modulatory Role of Omentin-1 in Inflammation: Cytokines and Dietary Intake.

Purpose: Obesity is known as a chronic inflammatory state whereby anti-inflammatory adipokines, such as omentin-1 levels, are decreased. The present study aims to determine omentin-1 levels in relation to dietary intake, inflammation, and immune response in healthy obese individuals.

Method: A total of 170 obese participants (body mass index [BMI] ≥ 30) were recruited in this cross-sectional study. Body composition was evaluated by a body composition analyzer, and inflammatory markers (high-sensitivity C-reactive protein [hs-CRP], interleukin (IL)-4, IL-6, IL-1β, IL-17, IL-10, IL-13, and tumor necrosis factor-alpha [TNF-α]) were measured by enzyme-linked immunosorbent assay (ELISA) kits.

Results: We observed associations between higher serum levels of omentin-1 and lower levels of fasting insulin, glucose, total cholesterol, IL-6, and TNF-α concentrations; higher levels of IL-13, IL-4, and IL-1β were associated with higher serum levels of omentin-1 (all p < 0.05). Omentin-1 levels were not associated with IL-10, hs-CRP, and IL-17 concentrations. We also observed associations between higher intake of saturated fatty acid (SFA) and omentin-1 levels, even after adjustment for total energy intake (p = 0.04). Women with low intake of SFA had higher levels of omentin-1 (p = 0.03); a similar relation was not observed in men.

Conclusion: Omentin-1 has an anti-inflammatory role in obesity and exerts its effects probably by inducing an increase in Th-2 cytokines comprising IL-13 and IL-4. Omentin-1 is not related to IL-17, a regulatory T cell cytokine, which modulates T helper balance. Levels of inflammatory cytokines are decreased in higher concentrations of omentin-1, except IL-1β. Lower intake of SFA may modify omentin-1 levels in women. Our study demonstrated the probable protective role of omentin-1 in obesity-related inflammation and insulin resistance.