PERIVASCULAR ADIPOSE TISSUE DYSFUNCTION IS DRIVEN BY META-INFLAMMATORY CHANGES IN A CARDIOMETABOLIC MODEL CHARACTERIZED BY THE COEXISTENCE OF HYPERTENSION AND OBESITY

Objective: Indirect evidence supports a pivotal role of perivascular adipose tissue (PVAT) in microvascular dysfunction associated with hypertension and obesity. The purpose of this work is to characterise the PVAT phenotype in patients with hypertension and obesity and to explore the mechanisms underlying PVAT dysfunction. Design and method: Small vessels (100-300 uM) from healthy controls (n=13) and patients with hypertension and obesity (n=27) were isolated and mounted for pressure myography or stored for further experiments. Functional evaluation was performed either in the presence or absence of PVAT to assess the PVAT-specific contribution to microvascular dysfunction. We adopted a mouse model characterized by exposure to high-fat diet and L-NAME supplementation as a mirror of our cardiometabolic patients. In vitro cross-talk model between human PVAT-like adipocytes and human endothelial cells via direct (transwell) and indirect (conditioned media) co-culture was adopted to recapitulate the phenotype. We investigated underpinning mechanisms via transcriptomic, metabolomic and lipidomic profiling and gain/loss-of-function assays. Results: Ex vivo microvascular function is severely impaired in cardiometabolic patients (p<0.0001). ACh vasodilation and L-NAME vasoinhibition were reduced with a PVAT specific contribution of 14.31% (p<0.001) and 18.71% (p<0.001), respectively. Transcriptomic, metabolomic and lipidomic analysis in diseased PVAT revealed an impaired TCA cycle with increased glycolysis and triglyceride storage. This was associated with an increased metabolic load and higher (2-to-5 fold, p<0.01) levels of inflammatory mediators (TNFa, IL1b, IL6) at the tissue level and in secretome. In vitro, overexpression of glycolytic genes in healthy adipocytes (gly-ACs) induces a pro-inflammatory phenotype. Pro-gly-ACs and PVAT-derived primary adipocytes from hypertensive and obese patients induce similar molecular changes as well as a reduction in eNOS dimerization, a surrogate for endothelial dysfunction, in co-cultured human endothelial cells. Reduction of glycolytic enzyme activation by competitive pharmacological antagonism or gene silencing in PVAT-derived primary adipocytes from hypertensive and obese patients rescues the phenotype. Conclusions: In the context of hypertension and obesity, dysfunctional PVAT is characterized by stunned metabolic activity and increased inflammatory burden, disrupting endothelial cells’ function. Targeting the metabolic shift in PVAT rescues the phenotype and prevents deleterious changes in the microvascular endothelium.