The Effects of Bariatric Surgery on Platelet Function and Endothelial Progenitor Cell Level and Function

Introduction: Obesity is associated with metabolic derangements and chronic inflammation. Bariatric surgery provides numerous benefits, including a sharp reduction in cardiovascular (CV) risk. The mechanism by which CV risk is reduced is unclear. We hypothesized this benefit may be related to modification in circulating endothelial progenitor cells (EPCs) and platelet reactivity. Accordingly, we aimed to assess platelet reactivity, EPC level and function, and SDF-1α level (chemokine related to EPC mobilization), before and after sleeve gastrectomy (SG), in morbidly obese individuals.

Methods: We enrolled 25 individuals who were morbidly obese (BMI≥40 kg/m2) or BMI≥35 kg/m2 with risk factors, aged 18-65 years, 84% women, who were planned to undergo SG. Blood samples were taken 3 times: before SG, at one and three months after SG, for platelet reactivity (assessed by P2Y12 VerifyNow assay), EPC circulating levels, identified by expression of CD133 and CD34, EPC capacity to form colonies, and plasma concentrations of SDF-1α.

Results: Following SG body weight decreased from 119.5±15 kg to 107.5±15.5 kg at 1-month (10% reduction, p=0.03), and to 95.5±13 kg at 3 months (20% reduction, p=0.0002). Platelet reactivity did not change significantly between time-points. At 1-month post-SG, level of CD34+ EPCs was higher than at baseline: 6.1±6% vs. 2.6±2%, p=0.03, yet decreased at 3 months to 1.9±1%, p=0.04. At 1-month post-SG, EPC capacity to form colonies was higher than at baseline, p=0.009; and decreased at 3 months post-SG. EPC viability did not change significantly between time-points. SDF1α level increased at 1-month post-BS, and decreased at 3 months.

Conclusions: We report higher EPC level and colony forming capacity after 1 month, and lower EPC level and colony formation after 3 months, in morbidly obese patients who underwent SG. These changes may be related to metabolic and inflammatory processes after SG and may contribute to CV risk modification.