Abstract 273: Phenotypic Differences Between Human Subcutaneous and Perivascular Adipose Tissues

Abstract

Objective: Human adipose lies in specific anatomic depots. Peri-vascular adipose appears unique and impacts blood vessel biology, but direct human data is limited. In view of their theorized roles, we tested the hypothesis that human peri-vascular and subcutaneous adipose tissue hold distinct phenotypic signatures. We also evaluated the impact of clinical parameters on adipose phenotype. Methods: Fresh human peri-vascular and subcutaneous adipose tissues were collected intra-operatively from patients undergoing major lower extremity amputation (n=27) and assayed for protein levels of the adipose-associated mediators IL-6, IL-8, leptin, TNF-α, MCP-1, adiponectin, resistin and PAI-1. Results: Leptin (2.4 fold, p=0.045) and adiponectin (1.8 fold, p=0.007) were significantly more abundant in subcutaneous compared to peri-vascular adipose (Table I). Clinical data were used to model associations between clinical characteristics and mediator levels. Age positively correlated with peri-vascular PAI-1 expression (β=0.64, p=0.042), and hyperlipidemia negatively correlated with peri-vascular adipose adiponectin (β=-1.18, p=0.039). Conclusions: While significant similarity was observed between subcutaneous and peri-vascular adipose from leg amputation patients, the differential in adipose derived hormones leptin and adiponectin provides direct human evidence that these tissue compartments hold distinct biologic roles. Further investigation into the unique nature of peri-vascular adipose may provide meaningful guidance in managing peripheral vascular disease.