High pulse pressure impairs cerebral artery endothelial function in young, but not old, mice

Multi-scale modelling of the effects of ageing, hypertension and exercise on the cerebral vasculature

Ageing and hypertension both have substantial, well-documented effects on the cerebral vasculature. The effects of aerobic exercise on cerebrovascular function and development, although less well understood, have also recently received significantly increased attention. There is now clear evidence that aerobic exercise yields both short- and long-term changes to cerebrovascular health, with significant potential to improve population brain health. However, there has as yet been no mathematical model of this, making it challenging to quantify the effects of aerobic exercise. One reason for this is the very different time scales between exercise (minutes/hours) and cerebrovascular development (years/decades). Here, a new mathematical model is proposed, one that incorporates short-term changes within a longer time scale. The model is calibrated against various experimental data sources and used to quantify the effects of ageing, hypertension, and exercise interventions on lifetime cerebrovascular health. The model predicts that high-intensity exercise has a significant positive effect on cerebral health; that antihypertensive treatment has a significant positive effect even after prolonged periods of hypertension; and that different interventions can strongly interact with each other. This model provides the foundation for future quantitative investigations into the critical role of aerobic exercise and other interventions in cerebrovascular health. KEY POINTS: Exercise has a significant and lifetime positive effect on the cerebral vasculature, which can counterbalance the negative effects of ageing and hypertension. A new model is presented that incorporates the effects of all three effects on the cerebral vasculature, using multiple time scales to include both short- and long-term effects. The model is calibrated against a range of experimental data and used to quantify the effects of different exercise regimes on cerebrovascular health for the first time. This model can be used in future to explore the lifetime effects of different lifestyles and interventions on population brain health.

Higher Long-Term Visit-to-Visit Blood Pressure Variability Is Associated With Severe Cerebral Small Vessel Disease in the General Population

Long-term visit-to-visit blood pressure (BP) variability is linked to various diseases, but its impact on cerebral small vessel disease (cSVD) burden, and its features remains uncertain. We analyzed 1284 participants from the Kailuan cohort (2006-2022). Visit-to-visit systolic BP (SBP), diastolic BP (DBP), and pulse pressure (PP) variability were categorized into tertiles (low, middle, high). Magnetic resonance imaging identified white matter hyperintensities (WMH), lacunae of presumed vascular origin (LA), cerebral microbleeds (CMBs), and visible perivascular spaces (PVS). Total cSVD burden was classified as none (0), mild (1), moderate (2), or severe (3-4) based on the presence of these features. Logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs). High SBP variability was associated with moderate cSVD burden (OR = 1.89, 95% CI: 1.09-3.29) and PVS (OR = 1.62, 95% CI: 1.10-2.39). High DBP variability was associated with LA (OR = 1.74, 95% CI: 1.06-2.84). High PP variability showed a significant risk for severe cSVD burden (OR = 2.49, 95% CI: 1.34-4.63). These associations were modified by age and hypertension status. Among young adults (age < 60 years), high PP variability was associated with severe cSVD burden (OR = 3.33, 95% CI: 1.31-8.44), LA (OR = 3.02, 95% CI: 1.31-6.93), and PVS (OR = 1.86, 95% CI: 1.20-2.88). The risk effects of SBP and PP variability on cSVD burden were significant only in participants with hypertension. High long-term visit-to-visit BP variability (BPV), particularly in combination with hypertension, is a significant risk factor for total cSVD. Special attention should be given to PP variability in younger adults.

Effects of high-intensity interval training in a cold environment on arterial stiffness and cerebral hemodynamics in sedentary Chinese college female students post-COVID-19

Many patients with COVID-19 experience increased arterial stiffness and abnormal cerebral hemodynamics. Although previous studies have explored the effects of cold environments on cardiovascular health and cerebral hemodynamics, there is still no research on the changes in cardiovascular and cerebral hemodynamics in sedentary female students recovering from COVID-19 while performing high-intensity interval training (HIIT) in cold environments. This study investigates the effects of 1 week of HIIT in a cold environment on cerebral hemodynamics and arterial stiffness (AS) in sedentary female college students, providing new insights into the pathophysiological mechanisms in this specific context. Thirty-six participants were randomly divided into a control group (n = 12), a room temperature (RE) group (n = 12), and a cold environment (CE) group (n = 12). HIIT was performed for four 4-min running training sessions, with a 4-min interval between each training session, The training duration was 1 week, with a frequency of 2 sessions per day, while the control group did not undergo any training. After training, the AS in the CE group significantly decreased (p < 0.05), with an average reduction of 11% in brachial-ankle pulse wave velocity, showing a significantly greater improvement compared to the RE group and the control group (p < 0.05), while no significant changes were observed in the RE group (p > 0.05). In the Y-Balance Tests (YBTs), the concentrations of cerebral oxygenated hemoglobin and total hemoglobin significantly increased (p < 0.05) during unilateral leg support tests in both the CE and RE groups, and the increase of CE group is greater than that of RE group. In contrast, in the control group, the concentrations of cerebral oxygenated hemoglobin and total hemoglobin significantly decreased during left leg support (p < 0.05). Our study found that performing HIIT in a cold environment not only effectively reduces AS in sedentary female college students after COVID-19, improves cardiovascular function, but also significantly enhances cerebral hemodynamics, helping them alleviate the negative impacts of post-COVID-19 sequelae and sedentary behavior on health. Future research should further explore the mechanisms by which sedentary behavior, post-COVID-19 recovery status, and adaptation to cold environments collectively influence cardiovascular function and cerebral hemodynamics, providing a more comprehensive understanding of these factors.

Examination of nonlinear associations between pulse pressure index and incident prediabetes susceptibility: a 5-year retrospective cohort investigation

Prediabetes and related complications constitute significant public health burdens globally. As an indicator closely associated with abnormal glucose metabolism and atherosclerosis, the utility of Pulse Pressure Index (PPI) as a prediabetes risk marker has not been explored. We performed a retrospective cohort analysis to investigate this putative association between PPI and prediabetes hazard. Our analysis encompassed 183,517 Chinese adults ≥ 20 years registered within the Rich Healthcare Group 2010-2016. PPI was defined as (systolic blood pressure - diastolic blood pressure)/systolic blood pressure. The relationship between PPI and prediabetes risk was assessed via Cox proportional hazards regression modeling. Non-linearity evaluations applied cubic spline fitting approaches alongside smooth curve analysis. Inflection points of PPI concerning prediabetes hazard were determined using two-piecewise Cox models. During a median follow-up of 3 years (2.17-3.96 years), new-onset prediabetes was documented in 20,607 patients (11.23%). Multivariate regression analysis showed that PPI was an independent risk factor for prediabetes, and the risk of prediabetes increased by 0.6% for every 1% increase in PPI (Hazard Ratio [HR]: 1.006, 95% Confidence Interval [CI] 1.004-1.008, P < 0.001). This association was non-significant for PPI ≤ 37.41% yet exhibited a sharp upsurge when PPI surpassed 37.41% (HR: 1.013, 95% CI 1.005-1.021, P = 0.0029). Our analysis unveils a positive, non-linear association between PPI and future prediabetes risk. Within defined PPI ranges, this relationship is negligible but dramatically elevates beyond identified thresholds.

Impact of arterial stiffness on cerebrovascular function: a review of evidence from humans and preclincal models

With advancing age, the cerebral vasculature becomes dysfunctional, and this dysfunction is associated with cognitive decline. However, the initiating cause of these age-related cerebrovascular impairments remains incompletely understood. A characteristic feature of the aging vasculature is the increase in stiffness of the large elastic arteries. This increase in arterial stiffness is associated with elevated pulse pressure and blood flow pulsatility in the cerebral vasculature. Evidence from both humans and rodents supports that increases in large elastic artery stiffness are associated with cerebrovascular impairments. These impacts on cerebrovascular function are wide-ranging and include reductions in global and regional cerebral blood flow, cerebral small vessel disease, endothelial cell dysfunction, and impaired perivascular clearance. Furthermore, recent findings suggest that the relationship between arterial stiffness and cerebrovascular function may be influenced by genetics, specifically APOE and NOTCH genotypes. Given the strength of the evidence that age-related increases in arterial stiffness have deleterious impacts on the brain, interventions that target arterial stiffness are needed. The purpose of this review is to summarize the evidence from human and rodent studies, supporting the role of increased arterial stiffness in age-related cerebrovascular impairments.