Validation of Circulating Endothelial Cells and Microparticles in Youth

Identification and validation of early chronic disease biomarkers in children is of paramount importance especially in the burgeoning arena of pediatric obesity research. Despite the presence of risk factors, few obese children develop overt cardiovascular disease (CVD) early in life. However, because CVD is a cumulative process occurring over time, identifying the earliest signs in order to intervene sooner may have a large impact on slowing its progression. Endothelial activation is one of the earliest detectable signs of the beginnings of CVD. However, accurately quantifying endothelial health in children has proven to be a major challenge. Direct measures of endothelial cell biology, such as circulating endothelial cells (CEC) and endothelial microparticles (EMP), have been extensively studied in adults and are associated with vascular diseases, CVD risk factors, and CVD events. Despite being well-validated in adults, CEC and EMP have not been formally evaluated as disease biomarkers in children and adolescents. Pediatric obesity is an ideal condition in which to validate CEC and EMP as disease biomarkers since adiposity in childhood is associated with CVD, type 2 diabetes mellitus, and premature death, later in life. The investigators primary focus in this study will be the evaluation of CEC and EMP as biomarkers of CVD risk and whether substantial changes in weight affect these biomarkers. The investigators propose to evaluate the change in levels of CEC and EMP in response to substantial weight loss in 32 adolescents with extreme obesity undergoing elective, clinically-indicated bariatric surgery.