Sex differences in arterial stiffness and sympathetic activity in older CKD patients

Abstract

Chronic kidney disease (CKD) is characterized by sympathetic nervous system overactivity that contributes to increased arterial stiffness and cardiovascular risk. While premenopausal females are relatively protected from cardiovascular disease in healthy individuals, older postmenopausal females without kidney disease have similar degrees of sympathetic overactivity, vascular stiffness and cardiovascular risk compared to older age-matched males in the general population. However, in the CKD population, cardiovascular mortality risk remains higher in older males compared to age-matched females and whether sex differences in neural and vascular function exist in older CKD patients is unknown. Therefore, we tested the hypothesis that compared to older females, older males with CKD have higher baseline sympathetic activity that is related to increased arterial stiffness. In 207 CKD patients (N=90 females, 62 ± 9 years; and N=117 males, 60 ± 9 years), we measured resting sympathetic nerve activity directed to muscle (MSNA) by microneurography at the peroneal nerve. At a separate visit, arterial stiffness was determined by carotid-to-femoral pulse wave velocity (PWV) using transcutaneous Doppler flow velocity (SphygmoCor®). Office blood pressure (BP) and 24-hour ambulatory BP monitoring (ABPM; Spacelabs) were performed using standard techniques. Resting MSNA was higher in males versus females with CKD (43 ± 10 vs 31 ± 14 bursts/min; p= 0.039). Both office and 24-hour ambulatory diastolic BP (79 ± 11 vs 67 ± 14 mmHg, p<0.001) and mean arterial pressure (96 ± 10 vs 88 ± 13 mmHg, p<0.001) were also higher in males versus females. PWV was not different between male and female groups (p= 0.157). There was no association between PWV and resting MSNA in males, while in females, there was an inverse relationship between PWV and MSNA burst frequency (r2=0.271; p=0.039) and burst incidence (r2=0.310; p=0.025). Older male CKD patients have higher resting MSNA, office and ambulatory BP compared to older females with CKD. In contrast, there were no differences in arterial stiffness measured as PWV between sexes. In males, increased MSNA was not associated with increased arterial stiffness, while MSNA was negatively correlated with PWV in females. Sex differences in neural and vascular function may impact cardiovascular outcomes in older patients with CKD. Supported by NIH grants R01HL135183, R33AT010457. 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.