5.3 THE INFLUENCE OF SEX AND AGE ON ARTERIAL FUNCTION IN RESPONSE TO AN ACUTE INFLAMMATORY STIMULUS

Abstract

Background: Aging is associated with increased arterial stiffness and chronic low-grade inflammation. Acute inflammatory stimulus in the presence of low-grade chronic inflammation briefly increases the risk of cardiovascular events. The risk of cardiovascular events also increases substantially in older compared to younger women, therefore the relationship between sex and aging is important to understand. Purpose: To describe the differential effects of age following induced systemic inflammation on arterial function, endothelial function, and wave reflection. Method: Healthy volunteers aged 18–35 yrs (n = 18, ≈26yr, male = 6) or 55–75 yrs (n = 21, ≈64yr, male = 9) participated. Ultrasound of the common carotid and brachial artery was performed, Beta-stiffness (β) and flow mediated dilation (FMD) were calculated. Aortic mean arterial (aMAP), pulse wave analysis with wave separation, pulse wave velocity (PWV) measurements were obtained in the supine position at rest using applanation tonometry. Participants received an influenza vaccine to induce acute inflammation following baseline measurements and returned for 24-hour follow-up. Results: C-reactive protein and interlukin-6 increased pre-to-post similar in all groups (p < 0.05). β was higher for older adults pre/post. (p < 0.05). Older males exhibited decreased MAP and reflected wave pressure (RP), but increased PWV following vaccination (p < 0.05). However, FMD significantly decreased only in young males. Conclusion: The results suggest that differential responses occur between young and older adults and between males and females in response to acute inflammation. Although inflammation increased similarly, inflammation had limited effects on vascular function in both young and old females, suggesting there are significant sex effects for arterial function in response to acute inflammation.