Chronodisruption enhances inflammatory cytokine release from visceral adipose tissue in obesity

Background: Chronodisruption, marked by circadian rhythm misalignment, is linked to inflammatory diseases like obesity. Chronotypes, reflecting individual circadian behavior, include morning, intermediate, and evening types, with evening chronotypes showing worse body composition and higher metabolic risk. This study evaluated the inflammatory profile of visceral adipose tissue (VAT) across chronotypes in individuals with obesity and examined clock gene expression. Methods: Twenty-five participants with obesity (11/14 F/M, BMI 41.59 ± 7.69 kg/m², age 41.13 ± 11.08 years) candidates for bariatric surgery were classified using the Morningness-Eveningness Questionnaire (MEQ): morning (36%), intermediate (28%), or evening (36%) chronotypes. VAT biopsies were analyzed for cytokines, chemokines, and growth factors via multiplex ELISA, and clock genes (PER1, CLOCK, BMAL1) were assessed using qPCR. Results: Body composition and biochemical parameters were similar across groups, but evening chronotypes had higher triglyceride levels (p = 0.012) and lower phase angle (p = 0.035). VAT inflammatory markers, including IL-1β (p = 0.04), IL-8 (p = 0.03), bFGF (p = 0.01), MCP-1 (p = 0.01), and MIP-1β (p = 0.05), were highest in evening and lowest in morning chronotypes. Evening chronotypes had significantly elevated bFGF levels compared to other groups (p = 0.04). PER1 mRNA expression was also higher in evening chronotypes (p = 0.02) and correlated with VAT-released bFGF (p = 0.03) and IL-1β (p = 0.03). MEQ scores negatively correlated with VAT bFGF (p = 0.02), MCP-1 (p = 0.02), and PER1 expressions. Conclusion: Despite similar metabolic profiles, evening chronotypes exhibit heightened VAT inflammation and altered clock gene expression, potentially worsening their metabolic risk.