ORCID Profile
0000-0003-4137-6840
Current Organisation
University of British Columbia
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Publisher: Wiley
Date: 09-01-2023
DOI: 10.1113/EP090813
Abstract: What is the central question of this study? We sought to investigate whether peripheral and cerebrovascular function are impaired in early and late postmenopausal females compared with premenopausal females, while also accounting for nitric oxide and estradiol levels. What is the main finding and its importance? We observed no differences in peripheral vascular and cerebrovascular function between healthy and physically active premenopausal females and early and late postmenopausal females. Our findings contradict previous cross‐sectional observations of vascular and cerebrovascular dysfunction across menopause. Longitudinal studies assessing vascular and cerebrovascular outcomes across the menopausal transition are warranted. The risk of cardiovascular and cerebrovascular disease increases in ageing females, coinciding with the onset of menopause. Differences in peripheral and cerebrovascular function across menopausal stages, however, are poorly characterized. The aim of this study was to compare peripheral and cerebrovascular function between healthy premenopausal (PRE), early (1–6 years after final menstrual period E‐POST) and late ( years after final menstrual period L‐POST) postmenopausal females. We also explored the association between reproductive hormones, NO bioavailability and cerebrovascular function. In 39 females (40–65 years of age), we measured arterial stiffness, brachial artery flow‐mediated dilatation, and cerebrovascular reactivity (CVR) to hypercapnia in the middle (MCAv) and internal (ICA) carotid arteries. Follicle‐stimulating hormone, estradiol, progesterone and plasma nitrate and nitrite concentrations were also measured. Years since final menstrual period (PRE, 0 ± 0 years E‐POST, 3 ± 1 years L‐POST, 11 ± 4 years P 0.001) and estradiol levels (PRE, 145.5 ± 65.6 pg ml −1 E‐POSTm 30.2 ± 81.2 pg ml −1 L‐POST, 7.7 ± 11.3 pg ml −1 P 0.001) were different between groups. All groups exceeded the guidelines for recommended physical activity. There were no group differences in blood pressure ( P = 0.382), arterial stiffness ( P = 0.129), flow‐mediated dilatation ( P = 0.696) or MCAv CVR ( P = 0.442). The ICA CVR blood flow response was lower in PRE compared with L‐POST (26.5 ± 19.2 vs. 47.8 ± 12.6% P = 0.010), but after adjusting for age these differences were no longer present. Flow‐mediated dilatation ( r = 0.313, P = 0.105) and ICA CVR ( r = −0.154, P = 0.495) were not associated with the estradiol concentration. There were no associations between the estradiol concentration and NO bioavailability. These results suggest that in healthy, physically active early and late postmenopausal females, vascular and cerebrovascular function is generally well preserved.
Publisher: Wiley
Date: 10-12-2022
DOI: 10.1113/JP281058
Publisher: American Physiological Society
Date: 10-2022
DOI: 10.1152/AJPHEART.00300.2022
Abstract: We observed similar MCA CVR and ICA reactivity in males and females. However, kinetic responses of the MCA to hypercapnia suggest that advancing age slows down the rate at which MCA velocity increases in response to hypercapnia. These data indicate distinct regulatory differences, and an impaired vasomotor control of the cerebrovasculature with advancing age, not detected by traditional methods.
Publisher: American Physiological Society
Date: 08-2022
Publisher: Canadian Science Publishing
Date: 08-2021
Publisher: University of Queensland Library
Date: 2023
DOI: 10.14264/CBF3E5B
Publisher: Wiley
Date: 30-06-2020
DOI: 10.1002/JCU.22891
Publisher: Wiley
Date: 14-12-2022
DOI: 10.1113/EP090031
Abstract: What is the central question of the study? What is the reliability of middle cerebral artery velocity cerebrovascular reactivity (CVR) when using traditional and novel outcomes, as measured by transcranial Doppler? What is the main finding and its importance? Traditional CVR approaches presented acceptable reproducibility but should be expressed as an absolute CVR. Large within‐ and between‐in idual differences in the middle cerebral artery velocity response profile support using a dynamic peak, rather than a set time point, for the most reliable interpretation. The study highlights the utility of novel kinetic CVR outcomes, but due to increased variability in time‐based metrics, this analysis requires larger s le sizes than traditional methods. Cerebrovascular reactivity (CVR) of middle cerebral artery velocity (MCAv) to CO 2 is a common method to assess cerebrovascular function. Yet, the approaches used to calculate CVR outcomes vary. The aim of this study was to explore the within‐ and between‐day reliability of traditional CVR outcomes. The second aim was to explore the reliability of novel kinetic‐based analyses. Healthy adults ( n = 10, 22.3 ± 3.4 years) completed assessments of CVR over 4 min using a fixed fraction of inspired CO 2 (6%). This was repeated across four separate visits (between‐day), and on one visit measures were repeated 2.5 h later (within‐day). No mean biases were present between assessments for traditional CVR metrics, expressed as absolute (cm/s/mmHg) or relative (%/mmHg) outcomes (minute 3, minute 4, peak 1 s, peak 30 s) (between‐day: P 0.14, η p 2 0.20 within‐day: P 0.22, d 0.27). Absolute, rather than relative, CVR yielded the most reproducible parameters (coefficient of variation: 8.1–13.2% vs. 14–83%, respectively). There were significant differences between CVR outcomes ( P 0.001, η p 2 0.89) dependent on the time point used to determine CVR, as a steady state MCAv response was rarely observed. Furthermore, the MCAv response was not reproducible within an in idual (κ = 0.15, P = 0.09). No mean differences were present for novel kinetic outcomes ( litude, time‐delay, time constant) (between‐day: P 0.05, d 0.33 within‐day: P 0.38, d 0.25). The results support the need for standardisation and indicate CVR should be defined as a dynamic peak, rather than a set time point for increased reliability. For novel kinetic outcomes variability was greater (CV: 8.7–120.9%) due to the nature of time‐based metrics.
Publisher: Elsevier BV
Date: 06-2021
Publisher: SAGE Publications
Date: 05-04-2023
DOI: 10.1177/0271678X231167753
Abstract: Neurovascular coupling (NVC) is the matching between local neuronal activity and regional cerebral blood flow (CBF), but little is known about the effects of age and sex on NVC. This study aimed to investigate the relationships and interaction between age and sex on NVC. Sixty-four healthy adults (18–85 years, N = 34 female) completed a visual stimulus evoked NVC assessment to a flashing checkerboard. NVC responses were measured in the posterior cerebral artery (PCAv) using transcranial Doppler ultrasound. A hierarchical multiple regression was used to determine the relationships between age, sex, and the age by sex interaction on NVC. There was a significant age by sex interaction for baseline (P = 0.001) and peak PCAv (P = 0.01), with a negative relationship with age in females (P 0.005), and no relationship in males (P ≥ 0.17). NVC responses as a percent increase from baseline showed a significant age by sex interaction (P = 0.014), with a positive relationship with age in females (P = 0.04) and no relationship in males (P = 0.17), even after adjusting for baseline PCAv. These data highlight important sex differences, with an association between age and NVC only apparent in females but not males, and thus a need to account for sex dependent effects of ageing when investigating cerebrovascular regulation.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Jodie Koep.