Abstract P234: High-fat Diet Reduces Beneficial Effect Of Perivascular Adipose Tissue On Arterial Stiffness

Abstract

Perivascular adipose tissue (PVAT) is has been shown to significantly contribute to arterial mechanics in health. Our previous results showed that, when including PVAT arterial stiffness is significantly reduced in the thoracic aorta. In this study, we aim to quantify the effect of PVAT on arterial stiffness in an animal model of adiposity driven hypertension. Our model was the thoracic aorta of Dahl Salt-Sensitive rats 8 weeks old on control (CON, n=2) and high-fat (HF, n=2) diets. Uniaxial mechanical tests for aorta + PVAT (+PVAT) and aorta - PVAT (-PVAT) were performed on a custom mechanical stretcher. The data reported is the low-stress stiffness calculated from the Cauchy stress-stretch curve. Blood pressure was also recorded for these animals. As expected, +PVAT samples’ stiffness appear to be lower than -PVAT samples. Including PVAT results in a 61% reduction of stiffness in the animals on CON diet. However, in animals fed a HF diet, the beneficial effect of PVAT is reduced to 21%. Surprisingly, while animals on HF diet had higher blood pressure compered to animals on CON diet, the stiffness recorded for -PVAT samples was lower in animals fed a HF vs CON diet. This could be due to an early remodeling mechanism which increases the cross-sectional area of the vessel, resulting in a lower values of stress for comparable values of stretch. Another possibility is that the collagen fibers in the tissue were not fully engaged during the test, due to the low level of deformation applied. Finally, more tests are required to confirm these initial observations. In conclusion, HF diet appears to decrease the beneficial effect of PVAT on the stiffness of the thoracic aorta.