245-LB: Aberrant DNA Methylation as a Contributor to Obesity-Associated Vascular Dysfunction

Obesity is a major risk factor for cardiovascular disease. We previously demonstrated an impaired vascular function in obese adults (OB). We now hypothesize a role of obesity-associated hypoxia in disturbing the methylation of genes involved in inflammation and vascular dysfunction and propose a mediating role of the hypoxia-inducible factor, HIF1α and the DNA hydroxymethylase, TET1. Methods: We obtained subcutaneous and visceral adipose tissue (AT) biopsies from bariatric patients (n=60; age: 36±7 yrs; BMI: 50.7±8.7 kg/m2) and non-obese (NOB) adults having elective surgeries (n=36; age: 36±2 yrs; BMI: 25.8±1 kg/m2). AT-isolated arterioles were tested for vasoreactivity in response to increasing pressure gradients. Arteriolar nitric oxide (NO) and reactive oxygen species (ROS) were measured. Protein expression of HIF1α and TET1 and promoter methylation/gene expression of leptin, IL1β, IL6, IL8, IL17, CXCL5, TNF-α, and IFNɣ were measured in the AT biopsy. Brachial artery flow-mediated dilation (FMD) was measured via doppler ultrasound. Results: Flow-induced dilation (FID) was 40-50% higher in NOB than OB adults across all pressure gradients (p Conclusion: Our results suggest that vascular dysfunction in OB adults may be attributed to aberrant DNA methylation and increased expression of adipocytokines in the hypoxic AT. A downstream target for this pathway could reside in endothelial cells of nearby arterioles and remote arteries resulting in vascular dysfunction. Disclosure M.M. Ali: None. C. Hassan: None. M. Masrur: None. F. Bianco: Consultant; Self; Intuitive, Medtronic. S.A. Phillips: None. A.M. Mahmoud: None. Funding National Institutes of Health (4R00HL140049, 031K99, HL14004901)