Franny Jongbloed

157 6 MORBID OBESITY, BARIATRIC SURGERY AND T-CELL AGING and T-cell differentiation was more pronounced in the female patients. This suggests a dominant effect of gender on T-cell aging. These effects could be mitigated since female patients undergoing bariatric surgery are usually younger than males. Whether female patients might benefit more from bariatric surgery concerning T-cell aging remains unclear. Further studies should fortify the role of gender on premature aging of morbidly obese patients. There are several limitations attached to this study. The sample size of morbidly obese patients and the healthy control group is relatively small which could conceal effects on different subpopulations within our cohort. Especially the selected group of patients investigated after surgery is small as well as the short follow-up period of one year. Further inclusions would increase the likelihood of revealing differences in the studied cohort. Also, a longer follow-up period gives additional information about the long-term effects of bariatric surgery on T-cell differentiation. In addition, since we measured RTL in the total circulating CD4 + and CD8 + T-cell compartments the effects seen in RTL might be the result of shifts in specific T-cell subsets as seen for the significant increase in CD28null T-cells due to obesity and MetS. Further studies should identify the changes in RTL within these specific subsets to correlate these findings. Finally, not all effects of obesity are reflected in the circulation and therefore investigating the effects on the corner stone of obesity, the fat tissue itself, will allow the association between the effect of excess of fat tissue and changes seen in the immune system. In conclusion, we show that the metabolic syndrome induced by morbid obesity causes telomere attrition in combination with enhanced T-cell differentiation in both circulating CD4 + and CD8 + T-cells, indicative of accelerated aging of the T-cell compartment. This shortening of telomeres and enhanced T-cell differentiation state are ameliorated shortly after bariatric surgery. These data suggest that obese patients with MetS are at risk for accelerated aging of the T-cell immune system and might benefit from bariatric surgery at an earlier stage. SUBJECTS AND METHODS Study design This study was designed as a non-randomized prospective cohort-study. The study was approved by the general Medical Ethical Committee (METC) with MEC identification number 2012-134 of the Erasmus University Medical Center, Rotterdam, the Netherlands. Approval of the inclusion center occurred via the Board of Directors of the Maasstad Hospital, Rotterdam, the Netherlands, with local identification number 2012-51. The