Wai-Ying Wendy Yau

Plasma phosphorylated tau 217 (pTau217) is an excellent biomarker of Alzheimer's disease (AD) pathology, but it remains uncertain whether pTau217 can predict amyloid-β (Aβ) and tau accumulation prior to Aβ positron emission tomography (PET) positivity. Here, we leverage data from a well-characterized prospective cohort of cognitively unimpaired older adults to examine mass spectrometry-based plasma %pTau217 (pTau217/non-phosphorylated-Tau217×100) relative to changes in Aβ/tau PET and cognition. A higher baseline %pTau217 was associated with faster Aβ and tau accumulation on PET, which then led to greater cognitive decline. Among individuals Aβ PET-negative at baseline, higher %pTau217 levels presaged increases in Aβ and tau PET signals. Together, our results suggest that very low %pTau217 in cognitively unimpaired older adults is associated with a minimal risk of AD pathology accumulation and cognitive decline.

BACKGROUND: Midlife hypertension is linked to white matter injury and dementia, partly through cerebral small vessel disease. We examined how age and systolic blood pressure (SBP) affect progression of 2 cerebral small vessel disease markers, white matter hyperintensity volume (WMHv), and peak width of skeletonized mean diffusivity, in the SPRINT (Systolic Blood Pressure Intervention) and ACCORD (Action to Control Cardiovascular Risk in Diabetes) trials. METHODS: We assessed age modification of intensive (P =0.18). However, intensive SBP treatment demonstrated a stepwise greater longitudinal WMHv reduction with younger age ≤65 years (−0.19 [95% CI, −0.28 to −0.11]), 66 to 75 years (−0.11 [95% CI, −0.19 to −0.02]), >75 years (−0.06 [95% CI, −0.20 to 0.09]), corresponding to respective reductions of 75%, 34%, and 19%. Intensive treatment produced a similar pattern in peak width of skeletonized mean diffusivity progression, with a significant treatment effect in those ≤65 only ( P =0.15 for overall treatment by age interaction). In ACCORD, intensive SBP-lowering was associated with reduced WMHv progression in the younger (≤65) compared with the older age group ( P =0.038). CONCLUSIONS: Intensive SBP control may be more effective in reducing white matter injury at younger compared with older ages.

Physical inactivity is a recognized modifiable risk factor for Alzheimer’s disease (AD), yet its relationship with progression of AD pathology in humans remains unclear, limiting the effective translation into prevention trials. Using pedometer-measured step counts in cognitively unimpaired older adults, we demonstrated an association between higher physical activity and slower cognitive and functional decline in individuals with elevated baseline amyloid. Importantly, this beneficial association was not related to lower amyloid burden at baseline or longitudinally. Instead, higher physical activity was associated with slower amyloid-related inferior temporal tau accumulation, which significantly mediated the association with slower cognitive decline. Dose–response analyses further revealed a curvilinear relationship, where the associations with slower tau accumulation and cognitive decline reached a plateau at a moderate level of physical activity (5,001–7,500 steps per day), potentially offering a more approachable goal for older sedentary individuals. Collectively, our findings support targeting physical inactivity as an intervention to modify the trajectory of preclinical AD in future prevention trials, and further suggest that preferentially enrolling sedentary individuals with elevated amyloid may maximize the likelihood of demonstrating a protective effect of physical activity on tau accumulation and cognitive and functional decline in early AD.

Background: Physically inactivity is associated with increased risk of dementia including Alzheimer’s disease (AD). Prior work from the Harvard Aging Brain Study (HABS) suggests that lower baseline physical activity in cognitively unimpaired individuals with elevated amyloid burden is associated with faster prospective cognitive decline. However, whether this detrimental effect on cognition in preclinical AD is mediated by accelerated tau pathology remains unclear.Method: We examined 293 baseline cognitively unimpaired older adults from HABS (Table 1). Baseline physical activity (mean steps per day) was measured using a waistband‐mounted pedometer (HJ‐720ITC; Omron Healthcare) worn over 7 consecutive days during waking hours. Using linear mixed effects models, we examined the interactive effects of baseline physical activity and amyloid PET burden (Pittsburgh Compound‐B) on longitudinal cognitive decline (Preclinical Alzheimer Cognitive Composite‐5 [PACC5]), adjusting for age, sex and education (APOE not significant). In a subset of 169 participants, we examined the interactive effects on longitudinal tau pathology (Flortaucipir PET) in 36 whole‐brain FreeSurfer cortical and limbic ROIs (FDR‐correction). We further investigated if the physical activity effects on PACC5 decline in preclinical AD are mediated by changes in tau.Result: In a larger sample of HABS participants with up to 13 years of cognitive follow‐up, we replicated the significant interaction between lower physical activity and elevated amyloid burden on faster prospective cognitive decline (ß=0.09, t=3.42, p<0.001; Figure 1A). We further demonstrated a novel interactive effect on tau pathology, where lower physical activity was associated with accelerated amyloid‐related tau accumulation in inferior temporal (ITC) and middle temporal (MTC) cortices (ITC: ß=‐0.10, t=‐3.36, FDR‐p=0.02; MTC: ß=‐0.09, t=‐3.27, FDR‐p=0.02; Figure 1B). Importantly, moderated mediation analyses revealed that accelerated tau accumulation fully mediated the effects of lower physical activity on faster cognitive decline in the setting of elevated amyloid (p<0.001, 100% mediated; Figure 2).Conclusion: Our findings provide strong support for promoting physical activity as a lifestyle intervention, in conjunction with anti‐amyloid therapy, to slow the onset and/or progression of early neocortical tau pathology and cognitive decline in preclinical AD.

Background: Physically inactivity is associated with increased risk of dementia including Alzheimer’s disease (AD). Prior work from the Harvard Aging Brain Study (HABS) suggests that lower baseline physical activity in cognitively unimpaired individuals with elevated amyloid burden is associated with faster prospective cognitive decline. However, whether this detrimental effect on cognition in preclinical AD is mediated by accelerated tau pathology remains unclear.Method: We examined 293 baseline cognitively unimpaired older adults from HABS (Table 1). Baseline physical activity (mean steps per day) was measured using a waistband‐mounted pedometer (HJ‐720ITC; Omron Healthcare) worn over 7 consecutive days during waking hours. Using linear mixed effects models, we examined the interactive effects of baseline physical activity and amyloid PET burden (Pittsburgh Compound‐B) on longitudinal cognitive decline (Preclinical Alzheimer Cognitive Composite‐5 [PACC5]), adjusting for age, sex and education (APOE not significant). In a subset of 169 participants, we examined the interactive effects on longitudinal tau pathology (Flortaucipir PET) in 36 whole‐brain FreeSurfer cortical and limbic ROIs (FDR‐correction). We further investigated if the physical activity effects on PACC5 decline in preclinical AD are mediated by changes in tau.Result: In a larger sample of HABS participants with up to 13 years of cognitive follow‐up, we replicated the significant interaction between lower physical activity and elevated amyloid burden on faster prospective cognitive decline (β = 0.09, t = 3.42, pp = 0.02; MTC: β = ‐0.09, t = ‐3.27, FDR‐p = 0.02; Figure 1B). Importantly, moderated mediation analyses revealed that accelerated tau accumulation fully mediated the effects of lower physical activity on faster cognitive decline in the setting of elevated amyloid (p<0.001, 100% mediated; Figure 2).Conclusion: Our findings provide strong support for promoting physical activity as a lifestyle intervention, in conjunction with anti‐amyloid therapy, to slow the onset and/or progression of early neocortical tau pathology and cognitive decline in preclinical AD.

Objective: Subclinical vascular brain injury is an increasingly recognized risk factor for stroke and dementia. Despite well‐established sex differences in vascular risk and disease prevalence, the impact of sex on drivers of subclinical vascular brain injury remains unclear, presenting a barrier to developing sex‐specific prevention guidelines. We aimed to establish the extent to which sex moderates associations between vascular risk factors and magnetic resonance imaging (MRI) measures of subclinical brain injury in stroke‐free older adults.Methods: We leveraged cross‐sectional data from 1,579 stroke‐ and dementia‐free Framingham Heart Study Offspring participants at exam 8 (age 65.7 ± 8.8 years, 53% women). Vascular risks were assessed using components of the Framingham Stroke Risk Profile (FSRP) and diastolic blood pressure (DBP). White matter hyperintensity volume (WMH), total cerebral brain volume (TBV), and covert brain infarcts were quantified using MRI. We examined whether vascular risk factors were associated with MRI measures across the combined cohort, and then determined whether sex modified these associations.Results: Higher FSRP and specifically systolic blood pressure (SBP) were associated with greater WMH. These associations were stronger in women and remained after adjusting for menopause age and hormone therapy use. By contrast, diabetes and lower DBP were associated with smaller TBV primarily in men. The DBP‐atrophy relationship was only observed in men with declining DBP or prior hypertension.Interpretation: Our findings highlight differential vulnerability to the impact of vascular risk factors on white matter health in women and global atrophy in men, supporting the development of sex‐specific guidelines to better preserve vascular brain health in aging. ANN NEUROL 2025;97:460–469

Vascular dysfunction is increasingly recognized as an important contributor to the pathogenesis of Alzheimer’s disease. Alterations in vascular endothelial growth factor (VEGF) pathways have been implicated as potential mechanisms. However, the specific impact of VEGF proteins in preclinical Alzheimer’s disease and their relationships with other Alzheimer’s disease and vascular pathologies during this critical early period remain to be elucidated. We included 317 older adults from the Harvard Aging Brain Study, a cohort of individuals who were cognitively unimpaired at baseline and followed longitudinally for up to 12 years. Baseline VEGF family protein levels (VEGFA, VEGFC, VEGFD, PGF and FLT1) were measured in fasting plasma using high-sensitivity immunoassays. Using linear mixed effects models, we examined the interactive effects of baseline plasma VEGF proteins and amyloid PET burden (Pittsburgh Compound-B) on longitudinal cognition (Preclinical Alzheimer Cognitive Composite-5). We further investigated if effects on cognition were mediated by early neocortical tau accumulation (flortaucipir PET burden in the inferior temporal cortex) or hippocampal atrophy. Lastly, we examined the impact of adjusting for baseline cardiovascular risk score or white matter hyperintensity volume. Baseline plasma VEGFA and PGF each showed a significant interaction with amyloid burden on prospective cognitive decline. Specifically, low VEGFA and high PGF were associated with greater cognitive decline in individuals with elevated amyloid, i.e. those on the Alzheimer’s disease continuum. Concordantly, low VEGFA and high PGF were associated with accelerated longitudinal tau accumulation in those with elevated amyloid. Moderated mediation analyses confirmed that accelerated tau accumulation fully mediated the effects of low VEGFA and partially mediated (31%) the effects of high PGF on faster amyloid-related cognitive decline. The effects of VEGFA and PGF on tau and cognition remained significant after adjusting for cardiovascular risk score or white matter hyperintensity volume. There were concordant but non-significant associations with longitudinal hippocampal atrophy. Together, our findings implicate low VEGFA and high PGF in accelerating early neocortical tau pathology and cognitive decline in preclinical Alzheimer’s disease. Additionally, our results underscore the potential of these minimally-invasive plasma biomarkers to inform the risk of Alzheimer’s disease progression in the preclinical population. Importantly, VEGFA and PGF appear to capture distinct effects from vascular risks and cerebrovascular injury. This highlights their potential as new therapeutic targets, in combination with anti-amyloid and traditional vascular risk reduction therapies, to slow the trajectory of preclinical Alzheimer’s disease and delay or prevent the onset of cognitive decline.

Objective: Elevated vascular risk and beta‐amyloid (Aβ) burden have been synergistically associated with cognitive decline in preclinical Alzheimer's disease (AD), although the underlying mechanisms remain unclear. We examined whether accelerated longitudinal tau accumulation mediates the vascular risk‐Aβ interaction on cognitive decline.Methods: We included 175 cognitively unimpaired older adults (age 70.5 ± 8.0 years). Baseline vascular risk was quantified using the office‐based Framingham Heart Study general cardiovascular disease risk score (FHS‐CVD). Baseline Aβ burden was measured with Pittsburgh Compound‐B positron emission tomography (PET). Tau burden was measured longitudinally (3.6 ± 1.5 years) with Flortaucipir PET, focusing on inferior temporal cortex (ITC). Cognition was assessed longitudinally (7.0 ± 2.0 years) using the Preclinical Alzheimer's Cognitive Composite. Linear mixed effects models examined the interactive effects of baseline vascular risk and Aβ on longitudinal ITC tau. Additionally, moderated mediation was used to determine whether tau accumulation mediated the FHS‐CVD*Aβ effect on cognitive decline.Results: We observed a significant interaction between elevated baseline FHS‐CVD and Aβ on greater ITC tau accumulation (p = 0.004), even in individuals with Aβ burden below the conventional threshold for amyloid positivity. Examining individual vascular risk factors, we found elevated systolic blood pressure and body mass index showed independent interactions with Aβ on longitudinal tau (both p < 0.0001). ITC tau accumulation mediated 33% of the interactive association of FHS‐CVD and Aβ on cognitive decline.Interpretation: Vascular risks interact with subthreshold levels of Aβ to promote cognitive decline, partially by accelerating early neocortical tau accumulation. Our findings support vascular risk reduction, especially treating hypertension and obesity, to attenuate Aβ‐related tau pathology and reduce late‐life cognitive decline. ANN NEUROL 2022;92:745–755

Autosomal‐dominant, Dutch‐type cerebral amyloid angiopathy (D‐CAA) offers a unique opportunity to develop biomarkers for pre‐symptomatic cerebral amyloid angiopathy (CAA). We hypothesized that neuroimaging measures of white matter injury would be present and progressive in D‐CAA prior to hemorrhagic lesions or symptomatic hemorrhage. In a longitudinal cohort of D‐CAA carriers and non‐carriers, we observed divergence of white matter injury measures between D‐CAA carriers and non‐carriers prior to the appearance of cerebral microbleeds and >14 years before the average age of first symptomatic hemorrhage. These results indicate that white matter disruption measures may be valuable cross‐sectional and longitudinal biomarkers of D‐CAA progression. ANN NEUROL 2022;92:358–363