T cell phenotypes associated with metabolically healthy obesity: Results from the Berlin Aging Study II

BackgroundObesity is associated with chronic low-grade inflammation leading to metabolic and cardiovascular diseases, but a subset of obese individuals is considered metabolically healthy. The underlying pathophysiologic mechanisms remain elusive and clinical studies on the relationship between inflammatory markers and metabolically healthy obesity (MHO) are scarce.MethodsIn this cross-sectional analysis, we included a sample of 437 older participants (60–84 years) from the Berlin Aging Study II (BASE-II). Peripheral blood mononuclear cells were isolated, immune cell subsets were analyzed with multiparameter flow cytometry and systemic cytokine levels were measured. Immune cell parameters were correlated with metabolic measures and multiple linear regression analysis was conducted and adjusted for various demographic and clinical factors.ResultsWe found that frequencies of naïve and memory CD4+ and CD8+ T cells inversely correlated with measures for insulin sensitivity in the older population. Moreover, the percentages of naïve CD4+ and CD8+ T cells were significantly higher, whereas activated T cells and IL-6 levels were lower in metabolically healthy compared to metabolically unhealthy obese individuals. The percentages of naïve CD4+ and CD8+ T cells were predictive for impaired insulin sensitivity (ß=0.16, p = 0.01 and ß=0.11, p = 0.04), and the association of naïve CD4+ T cells with insulin sensitivity persisted after multivariate adjustment (ß=0.14, p = 0.02).ConclusionsThese findings support the hypothesis that parameters of systemic inflammation can differentiate metabolically healthy from metabolically unhealthy obese individuals that are at higher risk for cardiometabolic diseases and may have clinical implications with regard to obesity treatment stratification.Trial registrationDRKS00009277. Registered 31 August 2015 - Retrospectively registered, https://www.base2.mpg.de/de