Serum Irisin Levels and Cardiovascular Risk in Obese Patients before and after Bariatric Surgery

Objectives: Irisin has emerged as a potential cardiovascular biomarker with protective effects. This study aimed to evaluate serum irisin levels and FNDC5 gene expression in obese individuals undergoing bariatric surgery and to assess irisin's role as a cardiovascular biomarker in obesity and post-surgery. Method: Forty severely obese participants and 40 healthy, normal-weight controls were evaluated at baseline, 6 months and 12 months after surgery. Serum irisin was measured using ELISA and FNDC5 gene expression was assessed via Real-Time PCR. Various biochemical, anthropometric and clinical parameters were also measured. Results: Serum irisin levels decreased significantly from 10.45±2.49 ng/mL at baseline to 7.66±1.49 ng/mL at 12 months post-surgery (p = 0.000). FNDC5 gene expression also significantly declined (p = 0.000). Irisin levels were positively correlated with BMI and FNDC5 expression and inversely correlated with cholesterol, LDL, triglycerides, CRP, MDA and hs-Tn. Higher irisin levels were associated with lower cholesterol, LDL, CRP and MDA levels. At 12 months, irisin was negatively correlated with cholesterol, ApoB/ApoA ratio and hs-Tn. Conclusion: Irisin may serve as a cardiovascular biomarker in obese individuals both before and after bariatric surgery. Elevated irisin levels are associated with obesity but decrease following surgery, correlating with inflammatory markers and cardiovascular risk factors. These results suggest that higher irisin levels could be linked to a lower cardiovascular risk in obese patients.