Visceral and subcutaneous adiposity and brachial artery vasodilator function

Area of Science:

• Cardiovascular Disease Research
• Obesity and Metabolism
• Vascular Biology

Background:

• Endothelial dysfunction is a potential mechanism linking obesity to cardiovascular disease (CVD).
• The relative contribution of visceral abdominal tissue (VAT) versus subcutaneous adipose tissue (SAT) to endothelial dysfunction is not fully understood.

Purpose of the Study:

• To test the hypothesis that visceral abdominal tissue (VAT) is more strongly associated with endothelium-dependent vasodilation than subcutaneous adipose tissue (SAT).
• To investigate the relationship between abdominal adipose tissue depots and brachial artery measures of endothelial function.

Main Methods:

• Analysis of data from the Framingham Offspring and Third Generation cohorts (n = 3,020).
• Computed tomography (CT) was used to assess VAT and SAT.
• Multivariable linear regression models were employed, adjusting for CVD risk factors, to relate VAT, SAT, BMI, and waist circumference (WC) with brachial artery measures, including flow-mediated dilation (FMD%).

Main Results:

• Both BMI, WC, VAT, and SAT were positively associated with baseline artery diameter and mean flow velocity.
• BMI, WC, and VAT were inversely associated with percentage of flow-mediated dilation (FMD%), while SAT was not.
• VAT showed a statistically significant inverse association with FMD% after adjusting for clinical covariates, though the incremental increase in explained variability compared to SAT was minimal.

Conclusions:

• Visceral abdominal tissue (VAT) is associated with impaired flow-mediated dilation (FMD%), suggesting a role in endothelial dysfunction.
• While VAT shows a stronger association with FMD% than SAT, the differential impact on vascular function, after accounting for traditional risk factors, appears minimal.
• Both VAT and SAT are related to baseline arterial characteristics, highlighting the systemic impact of adipose tissue distribution on vascular health.