Perceived Stress is Associated with Alzheimer's Disease Cerebrospinal Fluid Biomarkers in African Americans with Mild Cognitive Impairment

Perceived Stress, Blood Biomarkers, and Cognitive Functioning in Older Adults

INTRODUCTION

There is a substantial gap in knowledge regarding how perceived stress may influence the relationship between serum-measured biomarkers for Alzheimer's disease and cognitive decline.

METHODS

This study consists of 1118 older adult participants from the Chicago Health and Aging Project (CHAP) (60% Black participants and 63% female participants). Linear mixed effects regression models were conducted to examine the role of perceived stress in the association between three blood biomarkers: total tau (t-tau), glial fibrillary acid protein (GFAP), and neurofilament light chain (NfL) on global cognitive decline. Stratified analysis by stress level was also conducted to evaluate the associations between each blood biomarker and baseline cognitive function and decline. All models adjusted for age, race, sex, education, time, and their interactions with time.

RESULTS

The interaction of stress, NfL concentration, and time was statistically significant on global cognition ( β = -0.064 [SE = 0.028], p = .023) and on episodic memory ( β = -0.097 [SE = 0.036], p = .007).

CONCLUSIONS

Greater stress level worsens the association between high NfL concentration and cognitive decline. Stress management interventions may be helpful to reduce the rate of cognitive decline in individuals with high concentrations of NfL.

Lifetime Stressful Events Associated with Alzheimer's Pathologies, Neuroinflammation and Brain Structure in a Risk Enriched Cohort

OBJECTIVE

Along with the known effects of stress on brain structure and inflammatory processes, increasing evidence suggest a role of chronic stress in the pathogenesis of Alzheimer's disease (AD). We investigated the association of accumulated stressful life events (SLEs) with AD pathologies, neuroinflammation, and gray matter (GM) volume among cognitively unimpaired (CU) individuals at heightened risk of AD.

METHODS

This cross-sectional cohort study included 1,290 CU participants (aged 48-77) from the ALFA cohort with SLE, lumbar puncture (n = 393), and/or structural magnetic resonance imaging (n = 1,234) assessments. Using multiple regression analyses, we examined the associations of total SLEs with cerebrospinal fluid (1) phosphorylated (p)-tau181 and Aβ1-42/1-40 ratio, (2) interleukin 6 (IL-6), and (3) GM volumes voxel-wise. Further, we performed stratified and interaction analyses with sex, history of psychiatric disease, and evaluated SLEs during specific life periods.

RESULTS

Within the whole sample, only childhood and midlife SLEs, but not total SLEs, were associated with AD pathophysiology and neuroinflammation. Among those with a history of psychiatric disease SLEs were associated with higher p-tau181 and IL-6. Participants with history of psychiatric disease and men, showed lower Aβ1-42/1-40 with higher SLEs. Participants with history of psychiatric disease and women showed reduced GM volumes in somatic regions and prefrontal and limbic regions, respectively.

INTERPRETATION

We did not find evidence supporting the association of total SLEs with AD, neuroinflammation, and atrophy pathways. Instead, the associations appear to be contingent on events occurring during early and midlife, sex and history of psychiatric disease. ANN NEUROL 2024;95:1058-1068.

Longitudinal course of cognitive impairment in patients with atopic dermatitis

Atopic dermatitis (AD) is a common inflammatory skin disease. Cognitive dysfunction was recently demonstrated to be increased in adults and children with AD. However, little is known about the longitudinal course of cognitive impairment in AD and its relationship with pruritus. To investigate the longitudinal course and predictors of cognitive impairment in AD a prospective dermatology practice-based study was performed using questionnaires and evaluation by a dermatologist (n = 210). Patients with ≥ 2 visits were included (mean follow-up time: 318 days). Cognitive function was assessed using the Patient-Reported Outcomes Measurement Information System (PROMIS) Cognitive Function 8-item Short-Form. At baseline, 20.85% of patients had PROMIS T scores ≤ 45, indicating cognitive impairment (CI). Among patients with CI at baseline, 34.09% had persistent CI, 47.72% had a fluctuating course, and 18.18% had sustained improvement of cognitive function. In repeated-measures regression models, cognitive function scores declined overtime in patients with worse AD severity [SCORing Atopic Dermatitis (SCORAD): p = 0.01, Atopic Dermatitis Severity Index: p = 0.001], increased itch (p = 0.01), skin pain (p = 0.001), and sleep disturbance (p = 0.001). In multivariable logistic regression models, persistent CI was associated with female gender and depressive symptoms [moderate-to-severe Patient Health Questionnaire-9 score (PHQ9)]. Latent class analysis identified two classes of cognitive dysfunction: normal cognition (77.23%), moderate dysfunction (16.21%) and severe impairment (6.55%). Black/African-American race (p = 0.02), moderate-to-severe SCORAD (p = 0.03), dermatology life quality index (p < 0.0001), PHQ9 (p < 0.0001), itch (p = 0.02) and skin pain (p < 0.0001) were more likely to experience moderate dysfunction or severe cognitive impairment. AD is associated with a heterogeneous longitudinal course of cognitive function in adults, with some patients experiencing persistent CI over time.

Barriers and solutions to Alzheimer's disease clinical trial participation for Black Americans

Introduction

Black Americans are disproportionately burdened by Alzheimer's disease (AD) relative to other racial groups in the United States and continue to be underrepresented in AD clinical trials. This review explores the primary barriers for participation in clinical trials among Black Americans and provides literature-based recommendations to improve the inclusion of Black Americans in AD clinical trials.

Methods

We searched electronic databases and gray literature for articles published in the United States through January 1, 2023, ultimately identifying 26 key articles for inclusion.

Results

Barriers to participation in clinical trials for Black Americans are rooted in social determinants of health, including access to quality education and information, access to health care, economic stability, built environment, and community context. Best practices to improve the inclusion of Black Americans in clinical trials require pharmaceutical companies to adopt a multifaceted approach, investing in innovative strategies for site selection, development of local partnerships, outreach, and education.

Discussion

While multisectoral action must occur to effectively address the disproportionate burden of AD on Black Americans, the pharmaceutical industry has an important part to play in this space due to their central role in product development and clinical trials.

Neurovascular Dysfunction in Diverse Communities With Health Disparities-Contributions to Dementia and Alzheimer's Disease

Alzheimer's disease and related dementias (ADRD) are an expanding worldwide crisis. In the absence of scientific breakthroughs, the global prevalence of ADRD will continue to increase as more people are living longer. Racial or ethnic minority groups have an increased risk and incidence of ADRD and have often been neglected by the scientific research community. There is mounting evidence that vascular insults in the brain can initiate a series of biological events leading to neurodegeneration, cognitive impairment, and ADRD. We are a group of researchers interested in developing and expanding ADRD research, with an emphasis on vascular contributions to dementia, to serve our local diverse community. Toward this goal, the primary objective of this review was to investigate and better understand health disparities in Alabama and the contributions of the social determinants of health to those disparities, particularly in the context of vascular dysfunction in ADRD. Here, we explain the neurovascular dysfunction associated with Alzheimer's disease (AD) as well as the intrinsic and extrinsic risk factors contributing to dysfunction of the neurovascular unit (NVU). Next, we ascertain ethnoregional health disparities of individuals living in Alabama, as well as relevant vascular risk factors linked to AD. We also discuss current pharmaceutical and non-pharmaceutical treatment options for neurovascular dysfunction, mild cognitive impairment (MCI) and AD, including relevant studies and ongoing clinical trials. Overall, individuals in Alabama are adversely affected by social and structural determinants of health leading to health disparities, driven by rurality, ethnic minority status, and lower socioeconomic status (SES). In general, these communities have limited access to healthcare and healthy food and other amenities resulting in decreased opportunities for early diagnosis of and pharmaceutical treatments for ADRD. Although this review is focused on the current state of health disparities of ADRD patients in Alabama, future studies must include diversity of race, ethnicity, and region to best be able to treat all individuals affected by ADRD.

Interplay between stress-related genes may influence Alzheimer's disease development: The results of genetic interaction analyses of human data

Emerging evidence from experimental and clinical research suggests that stress-related genes may play key roles in AD development. The fact that genome-wide association studies were not able to detect a contribution of such genes to AD indicates the possibility that these genes may influence AD non-linearly, through interactions of their products. In this paper, we selected two stress-related genes (GCN2/EIF2AK4 and APP) based on recent findings from experimental studies which suggest that the interplay between these genes might influence AD in humans. To test this hypothesis, we evaluated the effects of interactions between SNPs in these two genes on AD occurrence, using the Health and Retirement Study data on white indidividuals. We found several interacting SNP-pairs whose associations with AD remained statistically significant after correction for multiple testing. These findings emphasize the importance of nonlinear mechanisms of polygenic AD regulation that cannot be detected in traditional association studies. To estimate collective effects of multiple interacting SNP-pairs on AD, we constructed a new composite index, called Interaction Polygenic Risk Score, and showed that its association with AD is highly statistically significant. These results open a new avenue in the analyses of mechanisms of complex multigenic AD regulation.