Muscadine Grape Extract Treatment Improves Aortic Pulse Wave Velocity and Superior Mesenteric Artery Pulsatility Index in Hypertensive Transgenic (mRen2)27 Female Rats

Hypertension is a major risk factor for heart disease and stroke, the leading causes of death in the United States. Hypertension is characterized by changes in vascular hemodynamics including vascular stiffness of the elastic conduit arteries and increased peripheral vascular resistance of the smaller muscular arteries that are associated with tissue damage. Dietary phenolic compounds are linked to beneficial cardiovascular effects. In this study, we investigated the influence of a muscadine grape extract (MGE; Piedmont Research & Development Corp.) on arterial stiffness and peripheral vascular resistance in hypertensive transgenic (mRen2)27 rats. We also investigated whether sex modulates MGE effects on arterial dysfunction in this rat model. MGE was administered in drinking water (0.2 mg polyphenolics/mL) starting at the age of 14 weeks, control animals were given regular water (n = 5 in each group, control and MGE‐treated female; n = 4 in each group, control and MGE‐treated male). After 6 weeks of treatment, noninvasive cardiovascular hemodynamic measurements were performed using a preclinical ultrasound system, Vevo LAZR (Fujifilm, Visual Sonics). Systolic blood pressure was measured using tail cuff plethysmography (NIBP‐8, Columbus instruments, Ohio). Aortic arch pulse wave velocity (PWV) was used as a measure of arterial stiffness and superior mesenteric artery (SMA) pulsatility index (PI), defined as PI = [(peak systolic velocity‐ end diastolic velocity)/mean flow velocity] was used as an indicator of peripheral vascular resistance. (mRen2)27 rats treated with MGE had lower aortic arch PWV compared with controls in both male (2.31 ± 0.33 vs. 3.79 ± 0.37 m/s, p < 0.05) and female (2.44 ± 0.13 vs. 3.62 ± 0.37 m/s, p < 0.05) rats. In addition, MGE‐treated female rats had lower SMA PI than control females (0.97 ± 0.07 vs. 1.27 ± 0.10, p < 0.05). There were no significant effects of the extract on SMA PI in males (1.19 ± 0.05 vs. 1.34 ± 0.07). These MGE effects were independent of changes in body weight (508 ± 3 vs. 493 ± 9 g in males, 282 ± 5 vs. 280 ± 5 g in females), cardiac index (4.5 ± 0.1 vs. 4.6 ± 0.3 mg/g in males, 4.9 ± 0.3 vs. 4.5 ± 0.2 mg/g in females), systolic blood pressure (188 ± 5 vs. 199 ± 4 mm Hg in males, 191 ± 12 vs. 194 ± 12 mm Hg in females) or cardiac function. In conclusion, six weeks of MGE treatment improved arterial stiffness in both male and female hypertensive rats. More pronounced beneficial vascular effects in females suggest that MGE actions in the arterial vasculature are modulated by sex. Support or Funding Information Chronic Disease Fund Research. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .