The omentum of obese girls harbors small adipocytes and browning transcrips

Severe obesity (SO) affects about 6% of youth in US, augmenting the risks for cardiovascular disease and Type 2 diabetes. Herein, we obtained paired omental (omVAT) and abdominal subcutaneous (SAT) adipose tissue biopsies from obese girls with SO, undergoing sleeve gastrectomy (SG), to test whether differences in cellular and transcriptomic profiles between omVAT and SAT depots affect insulin sensitivity differentially. Following weight loss, these analyses were repeated in a subgroup of subjects having a second SAT biopsy. We found that omVAT displayed smaller adipocytes compared to SAT, increased lipolysis through adipose triglyceride lipase (ATGL) phosphorylation, reduced inflammation and increased expression of browning/beige markers. Contrary to omVAT, SAT adipocyte diameter correlated with insulin resistance. Following SG, both weight and insulin sensitivity improved markedly in all subjects. SAT adipocytes size became smaller showing an increased lipolysis through perilipin-1 phosphorylation, decreased inflammation and increased expression in browning/beige markers. In summary, in adolescent girls with SO, both omVAT and SAT depots showed distinct cellular and transcriptomic profiles. Following weight loss, the SAT depot changed its cellular morphology and transcriptomic profiles into a more favorable one. These changes in the SAT depot may play a fundamental role in the resolution of insulin resistance. Human Abdominal Subcutaneous (SAT) and omental (omVAT) Adipose tissue mRNA profiles of 10 severe obese subjects and SAT mRNA profile of 4 subjects returned after weight loss (sequencing using Illumina Hi-Seq4000)