Sex-specific Differences in Arterial Stiffness and Endothelial Function in Untreated Hyperlipidemia

Background: The ACC/AHA guidelines for management of blood pressure (BP) and blood cholesterol provide significant updates to the identification and intervention of strategies for mitigating CVD risk. However, opportunities remain for enhancement especially in consideration of concomitant disease states and in sex differences. Recent reports have demonstrated the efficacy of measurements of arterial stiffness in which sex differences have been established in predicting the progression or development of cardio-metabolic pathologies. Thus, the purpose of the present study was to investigate sex-specific differences of elevated BP on arterial stiffness in a hyperlipidemic population. Methods: A total of 29 individuals (9 men:M, 20 women:W) with elevated fasting blood LDL cholesterol were recruited and grouped based on resting systolic blood pressure (SBP), with values ≤ 120 mmHg categorized as “normotensive” (n=5 M, 11 W) and SBP values > 120 mmHg as “elevated” BP (n=4 M, 9 W). Cardiovascular (CV) measures and blood samples for fasting LDL-cholesterol were collected before the clinical trial began thus, the data presented are baseline values. CV measurements included 24-hr ambulatory BP monitoring, endothelium-dependent vasodilator function via flow-mediated dilation (% FMD) test, and arterial stiffness determined via ultrasound of foot-to-foot transit time and velocity waveforms. Data are presented as (Mean ± SD) and significance was considered p<0.05. Results: Age was not significantly different between normotensive vs. elevated BP groups (M; 47.4 ± 16.6 vs. 47 ± 12.7 years, p>0.99), (W; 49 ±10.3 vs. 61.4 ± 8.6 years, p=0.12). LDL-cholesterol levels were not different between normotensive and elevated BP groups for men (p=0.38) or women (p=0.93). However, the normotensive group exhibited a greater change in % FMD vs. the elevated BP group (8.4 ± 3.2 vs. 5.9 ± 2.6%, p=0.022). Carotid-femoral pulse wave velocity (cfPWV) was significantly higher in the elevated BP group compared to normotensive (6 ± 1.3 vs. 7.7 ± 1.4 m/s, p=0.0016). When evaluating sex-specific differences, women had a higher % FMD in the normotensive group vs. elevated BP (9.5 ± 3.4 vs. 4.8 ± 1.7%, p=0.0037) whereas there was no difference in normotensive vs. elevated BP in men (p=0.99). Women with elevated BP also had greater elevations in cfPWV vs. normotensive women (6.2 ± 1.4 vs. 8.1 ± 1.6 m/s, p=0.022), while there was no difference in normotensive vs. elevated BP in men (p=0.68). Conclusion: Hyperlipidemic, but normotensive, women had greater blood vessel responses to FMD than hyperlipidemic women with elevated BP whereas there were no differences in men. Additionally, women with elevated BP had greater cfPWV than normotensive women, which implies greater arterial stiffness in those with elevated BP. These elevated BP measurements suggest a sex-specificity on arterial stiffness and endothelial function as changes were only seen in hyperlipidemic women but not hyperlipidemic men. California Strawberry Commission This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.