Does Increased Arterial Stiffness Herald Cognitive Impairment?

Nuances in Alzheimer's Genetic Risk Reveal Differential Predictions of Non-demented Memory Aging Trajectories: Selective Patterns by APOE Genotype and Sex

BACKGROUND

Apolipoprotein E (APOE) is a prominent genetic risk factor for Alzheimer's disease (AD) and a frequent target for associations with non-demented and cognitively impaired aging. APOE offers a unique opportunity to evaluate two dichotomous comparisons and selected gradations of APOE risk. Some evidence suggests that APOE effects may differ by sex and emerge especially in interaction with other AD-related biomarkers (e.g., vascular health).

METHODS

Longitudinal trajectories of non-demented adults (n = 632, 67% female, Mage = 68.9) populated a 40-year band of aging. Focusing on memory performance and individualized memory trajectories, a sequence of latent growth models was tested for predictions of (moderation between) APOE and pulse pressure (PP) as stratified by sex. The analyses (1) established robust benchmark PP effects on memory trajectories, (2) compared predictions of alternative dichotomous groupings (ε4- vs ε4+, ε2- vs ε2+), and (3) examined precision-based predictions by disaggregated APOE genotypes.

RESULTS

Healthier (lower) PP was associated with better memory performance and less decline. Therefore, all subsequent analyses were conducted in the interactive context of PP effects and sex stratification. The ε4-based dichotomization produced no differential genetic predictions. The ε2-based analyses showed sex differences, including selective protection for ε2-positive females. Exploratory follow-up disaggregated APOE genotype analyses suggested selective ε2 protection effects for both homozygotic and heterozygotic females.

CONCLUSION

Precision analyses of AD genetic risk will advance the understanding of underlying mechanisms and improve personalized implementation of interventions.

Arterial Stiffness and Cognition Among Adults: A Systematic Review and Meta-Analysis of Observational and Longitudinal Studies

Background

To estimate the strength of the cross‐sectional and longitudinal association between arterial stiffness, measured by pulse‐wave velocity, and cognitive function, distinguishing between global cognition, executive functions, and memory and to examine the influence of demographic, clinical, and assessment characteristics on this relationship.

Methods and Results

Systematic review of MEDLINE (via PubMed), Scopus, and WOS databases from their inception to March 2019, to identify cross‐sectional and longitudinal studies on the association between pulse‐wave velocity and cognitive domains (ie, global cognition, executive functions, and memory) among adult population. A total of 29 cross‐sectional and 9 longitudinal studies support the negative relationship between arterial stiffness and cognitive function, including global cognition, executive function, and memory. Demographic, clinical, and assessment characteristics did not substantially modify the strength of this association.

Conclusions

Evidence reveals a negative association between arterial stiffness, measured using pulse‐wave velocity, and cognition, specifically executive function, memory, and global cognition. This association seems to be independent of demographic, clinical, and assessment characteristics. These results accumulate evidence supporting that pulse‐wave velocity assessment could be a useful tool to identify individuals at high risk of cognitive decline or early stages of cognitive decline, to implement interventions aimed at slowing the progression to dementia.

Cognitive Impairment in Chronic Kidney Disease: Vascular Milieu and the Potential Therapeutic Role of Exercise

Chronic kidney disease (CKD) is considered a model of accelerated aging. More specifically, CKD leads to reduced physical functioning and increased frailty, increased vascular dysfunction, vascular calcification and arterial stiffness, high levels of systemic inflammation, and oxidative stress, as well as increased cognitive impairment. Increasing evidence suggests that the cognitive impairment associated with CKD may be related to cerebral small vessel disease and overall impairment in white matter integrity. The triad of poor physical function, vascular dysfunction, and cognitive impairment places patients living with CKD at an increased risk for loss of independence, poor health-related quality of life, morbidity, and mortality. The purpose of this review is to discuss the available evidence of cerebrovascular-renal axis and its interconnection with early and accelerated cognitive impairment in patients with CKD and the plausible role of exercise as a therapeutic modality. Understanding the cerebrovascular-renal axis pathophysiological link and its interconnection with physical function is important for clinicians in order to minimize the risk of loss of independence and improve quality of life in patients with CKD.