White Matter Hyperintensity Volume Research Articles

Visual and Auditory Sensory Impairments Differentially Relate with Alzheimer's Pathology.

We intended to investigate the relationships between visual sensory impairment (VSI) or auditory sensory impairment (ASI) and brain pathological changes associated with cognitive decline in older adults. We primarily tried to examine whether each sensory impairment is related to Alzheimer's disease (AD) pathology, specifically beta-amyloid (Aβ) deposition, through both cross-sectional and longitudinal approaches in cognitively unimpaired older adults. Self-report questionnaires on vision and hearing status were administered at the baseline. Neuroimaging scans including brain [11C] Pittsburgh Compound B PET and MRI, as well as clinical assessments, were performed at baseline and 2-year follow-up. Cross-sectional analyses showed that the VSI-positive group had significantly higher Aβ deposition than the VSI-negative group, whereas there was no significant association between ASI positivity and Aβ deposition. Longitudinal analyses revealed that VSI positivity at baseline was significantly associated with increased Aβ deposition over 2 years (β = 0.153, p = 0.025), although ASI positivity was not (β = 0.045, p = 0.518). VSI positivity at baseline was also significantly associated with greater atrophic changes in AD-related brain regions over the 2-year follow-up period (β = -0.207, p = 0.005), whereas ASI positivity was not (β = 0.024, p = 0.753). Neither VSI nor ASI positivity was related to cerebrovascular injury, as measured based on the white matter hyperintensity volume. The findings suggest that VSI is probably related to AD-specific pathological changes, which possibly mediate the reported relationship between VSI and cognitive decline. In contrast, ASI appears not associated with AD pathologies but may contribute to cognitive decline via other mechanisms.

Causal effect of cerebral small vessel disease on unexplained dizziness: A Mendelian randomization study

BackgroundPrevious cohort studies have suggested an association between cerebral small vessel disease (cSVD) and “unexplained dizziness”. The causality of this link remains uncertain, but it would be of significant clinical importance, considering the substantial number of patients presenting with unexplained dizziness is large. We aimed to investigate the causal effect of cSVD-related phenotypes on unexplained dizziness using a Mendelian randomization approach. MethodsGenetic instruments for each cSVD-related phenotype - white matter hyperintensity (WMH) volume, lacunar stroke (LS), perivascular spaces (PVS), and cerebral microbleeds (CMBs) - as well as unexplained dizziness were identified through large-scale genome-wide association studies. We conducted 2-sample Mendelian randomization analyses. The random-effects inverse-variance weighted (IVW) method was chosen for the primary analysis. For sensitivity analyses, we employed the weighted-median, MR-Egger, MR pleiotropy residual sum and outlier (MR-PRESSO), and leave-one-out analysis methods were implemented for the sensitivity analyses. ResultsWe successfully identified a significant causal effect of WMH volume on unexplained dizziness (odds ratio [95% CI], 1.12 [1.01–1.23]). However, we were unable to detect any significant causal effects of the other cSVD-related phenotypes on unexplained dizziness, with odds ratios [95% CI] of 1.03 [0.98–1.09] for LS, 0.75 [0.55–1.02] for white matter PVS, 1.02 [0.68–1.52] for basal ganglia PVS, 0.80 [0.43–1.51] for hippocampal PVS, 0.95 [0.90–1.00] for lobar CMBs, and 0.97 [0.92–1.01] for mixed CMBs respectively. The results from the sensitivity analyses were generally consistent with those of the primary analyses. ConclusionsThis MR study supports a causal relationship between WMH, a phenotype associated with cSVD, and the risk of unexplained dizziness, but does not support such a relationship between other cSVD-related phenotypes and unexplained dizziness. These findings require further validation through randomized controlled trials, larger cohort studies, and MR studies based on more extensive GWASs.

Alzheimer's disease genetic risk and changes in brain atrophy and white matter hyperintensities in cognitively unimpaired adults.

Reduced brain volumes and more prominent white matter hyperintensities on MRI scans are commonly observed among older adults without cognitive impairment. However, it remains unclear whether rates of change in these measures among cognitively normal adults differ as a function of genetic risk for late-onset Alzheimer's disease, including APOE-ɛ4, APOE-ɛ2 and Alzheimer's disease polygenic risk scores (AD-PRS), and whether these relationships are influenced by other variables. This longitudinal study examined the trajectories of regional brain volumes and white matter hyperintensities in relationship to APOE genotypes (N = 1541) and AD-PRS (N = 1093) in a harmonized dataset of middle-aged and older individuals with normal cognition at baseline (mean baseline age = 66 years, SD = 9.6) and an average of 5.3 years of MRI follow-up (max = 24 years). Atrophy on volumetric MRI scans was quantified in three ways: (i) a composite score of regions vulnerable to Alzheimer's disease (SPARE-AD); (ii) hippocampal volume; and (iii) a composite score of regions indexing advanced non-Alzheimer's disease-related brain aging (SPARE-BA). Global white matter hyperintensity volumes were derived from fluid attenuated inversion recovery (FLAIR) MRI. Using linear mixed effects models, there was an APOE-ɛ4 gene-dose effect on atrophy in the SPARE-AD composite and hippocampus, with greatest atrophy among ɛ4/ɛ4 carriers, followed by ɛ4 heterozygouts, and lowest among ɛ3 homozygouts and ɛ2/ɛ2 and ɛ2/ɛ3 carriers, who did not differ from one another. The negative associations of APOE-ɛ4 with atrophy were reduced among those with higher education (P < 0.04) and younger baseline ages (P < 0.03). Higher AD-PRS were also associated with greater atrophy in SPARE-AD (P = 0.035) and the hippocampus (P = 0.014), independent of APOE-ɛ4 status. APOE-ɛ2 status (ɛ2/ɛ2 and ɛ2/ɛ3 combined) was not related to baseline levels or atrophy in SPARE-AD, SPARE-BA or the hippocampus, but was related to greater increases in white matter hyperintensities (P = 0.014). Additionally, there was an APOE-ɛ4 × AD-PRS interaction in relation to white matter hyperintensities (P = 0.038), with greater increases in white matter hyperintensities among APOE-ɛ4 carriers with higher AD-PRS. APOE and AD-PRS associations with MRI measures did not differ by sex. These results suggest that APOE-ɛ4 and AD-PRS independently and additively influence longitudinal declines in brain volumes sensitive to Alzheimer's disease and synergistically increase white matter hyperintensity accumulation among cognitively normal individuals. Conversely, APOE-ɛ2 primarily influences white matter hyperintensity accumulation, not brain atrophy. Results are consistent with the view that genetic factors for Alzheimer's disease influence atrophy in a regionally specific manner, likely reflecting preclinical neurodegeneration, and that Alzheimer's disease risk genes contribute to white matter hyperintensity formation.

Associations of Amyloid Burden, White Matter Hyperintensities, and Hippocampal Volume With Cognitive Trajectories in the 90+ Study.

Amyloid pathology, vascular disease pathology, and pathologies affecting the medial temporal lobe are associated with cognitive trajectories in older adults. However, only limited evidence exists on how these pathologies influence cognition in the oldest old. We evaluated whether amyloid burden, white matter hyperintensity (WMH) volume, and hippocampal volume (HV) are associated with cognitive level and decline in the oldest old. This was a longitudinal, observational community-based cohort study. We included participants with 18F-florbetapir PET and MRI data from the 90+ Study. Amyloid load was measured using the standardized uptake value ratio in the precuneus/posterior cingulate with eroded white matter mask as reference. WMH volume was log-transformed. All imaging measures were standardized using sample means and SDs. HV and log-WMH volume were normalized by total intracranial volume using the residual approach. Global cognitive performance was measured by the Mini-Mental State Examination (MMSE) and modified MMSE (3MS) tests, repeated every 6 months. We used linear mixed-effects models with random intercepts; random slopes; and interaction between time, time squared, and imaging variables to estimate the associations of imaging variables with cognitive level and cognitive decline. Models were adjusted for demographics, APOE genotype, and health behaviors. The sample included 192 participants. The mean age was 92.9 years, 125 (65.1%) were female, 71 (37.0%) achieved a degree beyond college, and the median follow-up time was 3.0 years. A higher amyloid load was associated with a lower cognitive level (βMMSE = -0.82, 95% CI -1.17 to -0.46; β3MS = -2.77, 95% CI -3.69 to -1.84). A 1-SD decrease in HV was associated with a 0.70-point decrease in the MMSE score (95% CI -1.14 to -0.27) and a 2.27-point decrease in the 3MS score (95% CI -3.40 to -1.14). Clear nonlinear cognitive trajectories were detected. A higher amyloid burden and smaller HV were associated with faster cognitive decline. WMH volume was not significantly associated with cognitive level or decline. Amyloid burden and hippocampal atrophy are associated with both cognitive level and cognitive decline in the oldest old. Our findings shed light on how different pathologies contributed to driving cognitive function in the oldest old.

Neuroimaging correlates of Alzheimer's disease biomarker concentrations in a racially diverse high-risk cohort of middle-aged adults.

In this study, we investigated biomarkers in a midlife, racially diverse, at-risk cohort to facilitate early identification and intervention. We examined neuroimaging measures, including resting state functional magnetic resonance imaging (fMRI), white matter hyperintensity vo (WMH), and hippocampal volumes, alongside cerebrospinal fluid (CSF) markers. Our data set included 76 cognitively unimpaired, middle-aged, Black Americans (N=29, F/M=17/12) and Non-Hispanic White (N=47, F/M=27/20) individuals. We compared cerebrospinal fluid phosphorylated tau141 and amyloid beta (Aβ)42 to fMRI default mode network (DMN) subnetwork connectivity, WMH volumes, and hippocampal volumes. Results revealed a significant race × Aβ42 interaction in Black Americans: lower Aβ42 was associated with reduced DMN connectivity and increased WMH volumes regions but not in non-Hispanic White individuals. Our findings suggest that precuneus DMN connectivity and temporal WMHs may be linked to Alzheimer's disease risk pathology during middle age, particularly in Black Americans. Cerebrospinal fluid (CSF) amyloid beta (Aβ)42 relates to precuneus functional connectivity in Black, but not White, Americans. Higher white matter hyperintensity volume relates to lower CSF Aβ42 in Black Americans. Precuneus may be a hub for early Alzheimer's disease pathology changes detected by functional connectivity.

Cardiovascular risk and preclinical atherosclerosis are associated with white matter hyperintensities in apparently healthy adults: the population-based cross-sectional BIALYSTOK PLUS study.

White matter hyperintensities, present in patients and asymptomatic individuals, have been previously shown to be associated with atherosclerosis risk factors, such as high blood pressure, hypercholesterolemia, smoking, and diabetes. Our aim was to examine the associations between the volume of white matter hyperintensities and cardiovascular risk factors in the general, apparently healthy population. The analysis includes 735 participants (aged 20 to 79 years) without neurological or severe cardiac diseases. The participants underwent detailed clinical examination, including medical history, biochemical analyses, carotid arteries ultrasound, and brain magnetic resonance imaging, followed by white matter hyperintensities segmentation using the FreeSurfer tool. The participants were divided into 3 cardiovascular risk (CVR) categories based on the 2021 European Society of Cardiology guidelines. The median volume of white matter hyperintensities was 95.2 mm3 (interquartile range, 2.1-482 mm3). Multivariable analysis revealed positive independent association between the volume of white matter hyperintensities and CVR categories, glycated hemoglobin concentration, presence of carotid plaques, and central systolic blood pressure. An analysis including individuals without hypertension or diabetes revealed mean intima‑media thickness and high or very high cardiovascular risk class as independent predictors of white matter hyperintensities percentile. The cardiovascular risk class, presence of carotid plaques, increased intima‑media complex thickness, and diabetes are the main risk factors for white matter hyperintensities in apparently healthy adults. People without hypertension or diabetes but with higher CVR are also at a risk for developing white matter hyperintensities, which emphasizes the importance of CVR assessment for prediction of neurodegenerative changes.

Anti-Inflammatory Diet and Dementia in Older Adults With Cardiometabolic Diseases

Inflammation has been proposed as a mechanism linking cardiometabolic diseases (CMDs) to increased risk of dementia. However, whether an anti-inflammatory diet can support brain and cognitive health among people with CMDs is unclear. To examine CMD status and dietary inflammatory potential in association with dementia risk and brain magnetic resonance imaging (MRI) measures using joint effect analysis. The UK Biobank is an ongoing community-based cohort study with baseline assessments conducted between March 13, 2006, and October 1, 2010. The present study included 84 342 dementia-free older adults (≥60 years), who were followed up until January 20, 2022 (maximum, 15 years). A subsample (n = 8917) underwent brain MRI scans between May 2, 2014, and March 13, 2020. Baseline CMDs (including type 2 diabetes, heart disease, and stroke) were ascertained from medical records. Dietary Inflammatory Index scores (anti-inflammatory [≤-1.5 points], neutral [>-1.5 to <0.5 points], or proinflammatory [≥0.5 points]) were calculated from participants' average intake of 31 nutrients, assessed up to 5 times using the Oxford WebQ, a web-based, 24-hour dietary assessment. Incident dementia was identified through linkage to medical records. Regional brain volumes were collected from brain MRI scans. The study included 84 342 participants (mean [SD] age, 64.1 [2.9] years; 43 220 [51.2%] female). At baseline, 14 079 (16.7%) had at least 1 CMD. Over a median follow-up of 12.4 (IQR, 11.8-13.1) years, 1559 individuals (1.9%) developed dementia. With the use of joint effect analysis, the hazard ratio of dementia was 2.38 (95% CI, 1.93-2.93) for people with CMDs and a proinflammatory diet and 1.65 (95% CI, 1.36-2.00) for those with CMDs and an anti-inflammatory diet (reference: CMD-free, anti-inflammatory diet). Dementia risk was 31% lower (hazard ratio, 0.69; 95% CI, 0.55-0.88; P = .003) among people with CMDs and an anti-inflammatory diet. On brain MRI, participants with CMDs and an anti-inflammatory diet compared with a proinflammatory diet additionally had significantly larger gray matter volume (β = -0.15; 95% CI, -0.24 to -0.06 vs β = -0.27; 95% CI, -0.38 to -0.16) and smaller white matter hyperintensity volume (β = 0.05; 95% CI, -0.04 to 0.14 vs β = 0.16; 95% CI, 0.05-0.27). In this cohort study, people with CMDs and an anti-inflammatory compared with proinflammatory diet had a significantly lower hazard ratio of dementia, larger gray matter volume, and smaller white matter hyperintensity volume.

Association of cortical morphology, white matter hyperintensity, and glymphatic function in frontotemporal dementia variants.

Frontotemporal dementia (FTD) can be phenotypically divided into behavioral variant FTD (bvFTD), nonfluent variant primary progressive aphasia (nfvPPA), and semantic variant PPA (svPPA). However, the neural underpinnings of this phenotypic heterogeneity remain elusive. Cortical morphology, white matter hyperintensities (WMH), diffusion tensor image analysis along the perivascular space (DTI-ALPS), and their interrelationships were assessed in subtypes of FTD. Neuroimaging-transcriptional analyses on the regional cortical morphological deviances among subtypes were also performed. Changes in cortical thickness, surface area, gyrification, WMH, and DTI-ALPS were subtype-specific in FTD. The three morphologic indices are related to whole-brain WMH volume and cognitive performance, while cortical thickness is related to DTI-ALPS. Neuroimaging-transcriptional analyses identified key biological pathways linked to the formation and/or spread of TDP-43/tau pathologies. We found subtype-specific changes in cortical morphology, WMH, and glymphatic function in FTD. Our findings have the potential to contribute to the development of personalized predictions and treatment strategies for this disorder. Cortical morphologic changes, white matter hyperintensities (WMH), and glymphatic dysfunction are subtype-specific. Cortical morphologic changes, WMH, and glymphatic dysfunction are inter-correlated. Cortical morphologic changes and WMH burden contribute to cognitive impairments.

The Different Associations of White Matter Hyperintensities With Severity of Dementia and Cognitive Impairment According to the Distance From the Lateral Ventricular Surface in Patients With Alzheimer's Disease.

White matter hyperintensities (WMH) are common among the elderly. Although WMH play a key role in lowering the threshold for the clinical expression of dementia in Alzheimer's disease (AD)-related pathology, the clinical significance of their location is not fully understood. This study aimed to investigate the association between WMH and cognitive function according to the location of WMH in AD. Subjects underwent clinical evaluations including volumetric brain magnetic resonance imaging study and neuropsychological tests using the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet. WMH were calculated using automated quantification method. According to the distance from the lateral ventricular surface, WMH within 3 mm, WMH within 3-13 mm, and WMH over 13 mm were classified as juxtaventricular WMH (JVWMH), periventricular WMH (PVWMH), and deep WMH (DWMH), respectively. Total WMH volume was associated with poor performance in categorical verbal fluency test (β=-0.197, p=0.035). JVWMH volume was associated with poor performances on categorical verbal fluency test (β=-0.201, p=0.032) and forward digit span test (β= -0.250, p=0.012). PVWMH volume was associated with poor performances on categorical verbal fluency test (β=-0.185, p=0.042) and word list memory test (β=-0.165, p=0.042), whereas DWMH volume showed no association with cognitive tests. PVWMH volume were also related to Clinical Dementia Rating Scale Sum of Boxes score (β=0.180, p=0.026). WMH appear to exhibit different associations with the severity of dementia and cognitive impairment according to the distance from ventricle surface in AD.

White matter hyperintensity shape is related to long-term progression of cerebrovascular disease in community-dwelling older adults.

White matter hyperintensity (WMH) shape is associated with long-term dementia risk in community-dwelling older adults, however, the underlying structural correlates of this association are unknown. We therefore aimed to investigate the association between baseline WMH shape and cerebrovascular disease progression over time in community-dwelling older adults. The association of WMH shape and cerebrovascular disease markers was investigated using linear and logistic regression models in the Age, Gene/Environment Susceptibility-Reykjavik (AGES) study (n = 2297; average time to follow-up: 5.2 years). A more irregular shape of periventricular/confluent WMH at baseline was associated with a larger increase in WMH volume, and with occurrence of new subcortical infarcts, new microbleeds, new enlarged perivascular spaces, and new cerebellar infarcts at the 5.2-year follow-up (all p < 0.05). Furthermore, less elongated and more irregularly shaped deep WMHs were associated with a larger increase in WMH volume, and new cortical infarcts at follow-up (p < 0.05). A less elongated shape of deep WMH was associated with new microbleeds at follow-up (p < 0.05). Our findings show that WMH shape may be indicative of the type of cerebrovascular disease marker progression. This underlines the significance of WMH shape to aid in the assessment of cerebrovascular disease progression.

Impact of Systolic Blood Viscosity on Deep White Matter Hyperintensities in Patients With Acute Ischemic Stroke.

Elevated blood viscosity (BV), a critical determinant in blood rheology, is a contributing factor in cerebrovascular diseases. The specific influence of BV on small vessel disease burden remains unexplored. This study aims to examine the relationship between BV and regional white matter hyperintensity (WMH) volume in patients with acute ischemic stroke. We enrolled a cohort of 302 patients with acute ischemic stroke or transient ischemic attack who were admitted to a hospital within 7 days of symptom onset in this study. We measured whole BV using a scanning capillary-tube viscometer and categorized systolic blood viscosity into 3 groups based on established references. We quantified and normalized WMH volumes using automated localization and segmentation software by NEUROPHET Inc. We performed multivariable logistic regression analysis to assess the correlation between systolic BV and WMH. The mean subject age was 66.7±13.4 years, and 38.7% (n=117) of the participants were female. Among a total of 302 patients, patients with higher deep WMH volume (T3) were typically older and had an atrial fibrillation, strokes of cardioembolic or undetermined cause, elevated levels of C-reactive protein, diastolic blood viscosity and systolic BV. A multivariable adjustment revealed a significant association between high systolic BV and increased deep-WMH volume (odds ratio [OR], 2.636 [95% CI, 1.225-5.673]). Elevated systolic BV is more likely to be associated with deep WMH volume in patients with acute ischemic stroke or transient ischemic attack. These findings reveal novel therapeutic strategies focusing on blood rheology to enhance cerebral microcirculation in stroke management.

Estimated Pulse-Wave Velocity and Magnetic Resonance Imaging Markers of Cerebral Small-Vessel Disease in the NOMAS.

Pulse-wave velocity is a measure of arterial stiffness and a risk factor for cardiovascular disease. Recently, an estimated pulse-wave velocity (ePWV) was introduced that was predictive of increased risk of cardiovascular disease. Our objective was to determine whether ePWV was associated with cerebral small-vessel disease on magnetic resonance imaging. We included 1257 participants from the NOMAS (Northern Manhattan Study). The ePWV values were calculated using a nonlinear function of age and mean arterial blood pressure. The association between ePWV and white matter hyperintensity volume was assessed. Modification by race and ethnicity was evaluated. Associations between ePWV and other cerebral small-vessel disease markers, covert brain infarcts, cerebral microbleeds, and enlarged perivascular spaces, were explored as secondary outcomes. Mean±SD age of the cohort was 64±8 years; 61% were women; 18% self-identified as non-Hispanic Black, 67% as Hispanic, and 15% as non-Hispanic White individuals. Mean±SD ePWV was 11±2 m/s in the total NOMAS population and was similar across race and ethnic groups. The ePWV was significantly associated with white matter hyperintensity volume (β=0.23 [95% CI, 0.20-0.26]) after adjustment. Race and ethnicity modified the association between ePWV and white matter hyperintensity volume, with stronger associations in Hispanic and non-Hispanic Black individuals. Significant associations were found between ePWV and covert brain infarcts, cerebral microbleeds, and perivascular spaces after adjustment. The ePWV function may provide a vascular mechanism for deleterious cerebrovascular outcomes in individuals with cerebral small-vessel disease and is particularly apparent in the racial and ethnic minorities represented in the NOMAS cohort.

Interplay of Large Neutral Amino Acids, Metabolic Syndrome, and Apolipoprotein E ε4 on Brain Integrity at Midlife.

Large neutral amino acids (LNAAs) tryptophan and phenylalanine have been implicated in the pathogenesis of neurodegenerative diseases. Given limited research on the effects of LNAA on brain health across different life stages, vascular risk, and genetic backgrounds, our study aimed to explore the interaction of LNAA levels, metabolic syndrome (MetS), and the presence of the apolipoprotein E ε4 (ApoE ε4) allele brain integrity at midlife. Sixty-eight adults aged 40-61 underwent a health assessment to calculate the number of MetS components, quantify LNAA, measure white matter hyperintensity (WMH) volume, and genotype ApoE ε4. Multivariate linear regression analyses were performed to test the joint effect of LNAA, MetS, and ApoE ε4 on WMH while adjusting for sex, age, and education. Significant 3-way interactions were observed between serum tryptophan (β = 0.042, SE = 0.018, p &lt; 0.05) and phenylalanine (β = 0.044, SE = 0.013, p &lt; 0.01) levels, number of MetS components, and ApoE ε4 alleles status on WMH volume. Neither individual LNAA levels nor MetS components alone predicted WMH volume. The study highlights significant 3-way interactions between LNAA, MetS, and genetic risk factors in the pathology of WMH, particularly in individuals genetically predisposed to Alzheimer's disease. These interactions suggest differential impacts of LNAA on WMH volume dependent on both genetic and metabolic factors. Results emphasize the need for personalized metabolic and genetic profile assessments in neurodegenerative disease management.

Latent profiles of modifiable dementia risk factors in later midlife: relationships with incident dementia, cognition, and neuroimaging outcomes.

In 2020, the Lancet Commission identified 12 modifiable factors that increase population-level dementia risk. It is unclear if these risk factors co-occur among individuals in a clinically meaningful way. Using latent class analysis, we identified profiles of modifiable dementia risk factors in dementia-free adults aged 60-64 years from the UK Biobank. We then estimated associations between these profiles with incident dementia, cognition, and neuroimaging outcomes, and explored the differences across profiles in the effects of a polygenic risk score for Alzheimer's disease on outcomes. In 55,333 males and 63,063 females, three sex-specific latent profiles were identified: cardiometabolic risk, substance use-related risk, and low risk. The cardiometabolic risk profile in both males and females was associated with greater incidence of all-cause dementia (male: OR [95% CI] = 2.33 [2.03, 2.66]; female: OR [95% CI] = 1.44 [1.24, 1.68]), poorer cognitive performance, greater brain atrophy, and greater white matter hyperintensity volume compared to the low risk profile. The substance use-related risk profile in males was associated with poorer cognitive performance and greater white matter hyperintensities compared to the low risk profile, but no difference in all-cause dementia incidence was observed (OR [95% CI] = 1.00 [0.95, 1.06]). In females, the substance use-related risk profile demonstrated increased dementia incidence (OR [95% CI] = 1.58 [1.57, 1.58]) and greater brain atrophy but smaller white matter hyperintensity volume compared to the low risk profile. The polygenic risk score had larger effects among females, and differentially influenced outcomes across profiles; for instance, there were larger effects of the polygenic risk score on atrophy in the cardiometabolic profile vs. the low risk profile among males, and larger effects of the polygenic risk score on loss of white matter integrity in the cardiometabolic profile vs. the low risk profile among females. These results reveal three modifiable dementia risk profiles, their unique cognitive/neuroimaging outcomes, and their interactions with genetic risk for Alzheimer's disease. These differences highlight the need to consider population heterogeneity in risk prediction tools and in planning personalized prevention strategies.

The relationship between intracranial atherosclerosis and white matter hyperintensity in ischemic stroke patients: a retrospective cross-sectional study using high-resolution magnetic resonance vessel wall imaging.

Both intracranial atherosclerosis and white matter hyperintensity (WMH) are prevalent among the stroke population. However, the relationship between intracranial atherosclerosis and WMH has not been fully elucidated. Therefore, the aim of this study was to investigate the relationship between the characteristics of intracranial atherosclerotic plaques and the severity of WMH in patients with ischemic stroke using high-resolution magnetic resonance vessel wall imaging. Patients hospitalized with ischemic stroke and concurrent intracranial atherosclerosis at Beijing Tsinghua Changgung Hospital, a tertiary comprehensive stroke center, who underwent high-resolution magnetic resonance vessel wall imaging and conventional brain magnetic resonance imaging were continuously recruited from January 2018 to December 2018. Both intracranial plaque characteristics (plaque number, maximum wall thickness, luminal stenosis, T1 hyperintensity, and plaque length) and WMH severity (Fazekas score and volume) were evaluated. Spearman correlation or point-biserial correlation analysis was used to determine the association between clinical characteristics and WMH volume. The independent association between intracranial plaque characteristics and the severity as well as WMH score was analyzed using logistic regression. The associations of intracranial plaque characteristics with total white matter hyperintensity (TWMH) volume, periventricular white matter hyperintensity (PWMH) volume and deep white matter hyperintensity (DWMH) volume were determined using multilevel mixed-effects linear regression. A total of 159 subjects (mean age: 64.0±12.5 years; 103 males) were included into analysis. Spearman correlation analysis indicated that age was associated with TWMH volume (r=0.529, P<0.001), PWMH volume (r=0.523, P<0.001) and DWMH volume (r=0.515, P<0.001). Point-biserial correlation analysis indicated that smoking (r=-0.183, P=0.021) and hypertension (r=0.159, P=0.045) were associated with DWMH volume. After adjusting for confounding factors, logistic regression analysis showed plaque number was significantly associated with the presence of severe WMH [odds ratio (OR), 1.590; 95% CI, 1.241-2.035, P<0.001], PWMH score of 3 (OR, 1.726; 95% CI, 1.074-2.775, P=0.024), and DWMH score of 2 (OR, 1.561; 95% CI, 1.150-2.118, P=0.004). Intracranial artery luminal stenosis was associated with presence of severe WMH (OR, 1.032; 95% CI, 1.002-1.064, P=0.039) and PWMH score of 2 (OR, 1.057; 95% CI, 1.008-1.109, P=0.023). Multilevel mixed-effects linear regression analysis showed that plaque number was associated with DWMH volume (β=0.128; 95% CI, 0.016-0.240; P=0.026) after adjusted for age and sex. In ischemic stroke patients, intracranial atherosclerotic plaque characteristics as measured by plaque number and luminal stenosis were associated with WMH burden.

Association of Arterial Stiffness Index and Brain Structure in the UK Biobank: A 10-Year Retrospective Analysis.

Arterial stiffening and changes in brain structure both occur with normal aging and can be exacerbated via acquired health conditions. While cross-sectional associations exist, the longitudinal relationship between arterial stiffness and brain structure remains unclear. In this study, we investigated 1) associations between baseline arterial stiffness index (ASI) and brain structure (global and regional grey matter volumes (GMV), white matter hyperintensities (WMH)) 10-years post-baseline (10.4±0.8 years) and 2) associations between the 10-year change in ASI from baseline and brain structure 10-years post-baseline in 650 healthy middle- to older-aged adults (53.4±7.5 years) from the UK Biobank. We observed significant associations between baseline ASI and GMV (p<0.001) and WMH (p=0.0036) 10-years post-baseline. No significant associations between 10-year change in ASI and brain structure (global GMV p=0.24; WMH volume p=0.87) were observed. There were significant associations of baseline ASI in 2 of 60 regional brain volumes analyzed (right posterior superior temporal gyrus p=0.001; left superior lateral occipital cortex p<0.001). Strong associations with baseline ASI, but not changes in ASI over 10-years, suggest arterial stiffness at the entry point of older adulthood is more impactful on brain structure 10-years later compared to age-related stiffening. Based on these associations, we suggest clinical monitoring and potential intervention for reducing arterial stiffness should occur in midlife to reduce vascular contributions to structural changes in the brain, supporting a healthy trajectory of brain aging. Our findings also support use of ASI as a surrogate for gold standard measures in showing overall relationships between arterial stiffness and brain structure.

CSF1R-Related Disorder: Prevalence of CSF1R Variants and Their Clinical Significance in the UK Population.

CSF1R-related disorder (CSF1R-RD) is a devastating neurodegenerative disorder caused by variants in the colony stimulating factor-1 receptor (CSF1R) gene. CSF1R-RD leads to a variable combination of cognitive impairment, movement disorders, upper motor neuron signs, and spasticity with associated imaging abnormalities in brain white matter. Although increasingly recognized, there is evidence that it is significantly underdiagnosed or misdiagnosed, and its true prevalence is unknown. We leveraged the large data set of the UK Biobank to determine the prevalence of CSF1R mutations in the UK population and identify clinical phenotypes associated with these variants. Pathogenic and likely pathogenic CSF1R variants were identified in UK Biobank whole-exome sequencing data (N = 470,000). Medical history, including neurologic and psychiatric disease, were determined from self-reported and hospital collected codes, and the volume of MRI white matter hyperintensities were compared between variant carriers and controls. We identified 25 individuals carrying 18 unique pathogenic variants and 107 individuals carrying 44 unique likely pathogenic variants-combined prevalence 132 (∼1 in 3,500). Pathogenic CSF1R variant carriers had increased risk of psychiatric disease (OR: 5.15, p = 0.0079), depression (OR: 10.52, p = 0.0015), and Parkinson disease (OR: 19.80, p = 0.0038). Using algorithmically defined diagnosis data, pathogenic or likely pathogenic variants (the combined group) carriers were at higher risk for both dementia (OR: 2.50, p = 0.046) and vascular dementia (OR: 4.72, p = 0.032). Damaging variants in CSF1R are more common than expected in the general population and are associated with cognitive, psychiatric, and movement disorder diagnoses, which may reflect clinical manifestation of the disease. This study suggests that CSF1R-RD is either underreported, not diagnosed because of lack of genetic screening or that there is reduced penetrance.

Characterization of white matter hyperintensities in Down syndrome.

In Down syndrome (DS), white matter hyperintensities (WMHs) are highly prevalent, yet their topography and association with sociodemographic data and Alzheimer's disease (AD) biomarkers remain largely unexplored. In 261 DS adults and 131 euploid controls, fluid-attenuated inversion recovery magnetic resonance imaging scans were segmented and WMHs were extracted in concentric white matter layers and lobar regions. We tested associations with AD clinical stages, sociodemographic data, cerebrospinal fluid (CSF) AD biomarkers, and gray matter (GM) volume. In DS, total WMHs arose at age 43 and showed stronger associations with age than in controls. WMH volume increased along the AD continuum, particularly in periventricular regions, and frontal, parietal, and occipital lobes. Associations were found with CSF biomarkers and temporo-parietal GM volumes. WMHs increase 10 years before AD symptom onset in DS and are closely linked with AD biomarkers and neurodegeneration. This suggests a direct connection to AD pathophysiology, independent of vascular risks. White matter hyperintensities (WMHs) increased 10 years before Alzheimer's disease symptom onset in Down syndrome (DS). WMHs were strongly associated in DS with the neurofilament light chain biomarker. WMHs were more associated in DS with gray matter volume in parieto-temporal areas.

Greater White Matter Hyperintensity Volume Is Associated with the Number of Microhemorrhages in Preclinical Alzheimer’s Disease

BackgroundIncreased white matter hyperintensity (WMH) volume visible on MRI is a common finding in Alzheimer’s disease (AD). We hypothesized that WMH in preclinical AD is associated with the presence of advanced vessel amyloidosis manifested as microhemorrhages (MCH).Objectives1) To assess the relationship between baseline WMH volume and baseline MCH. 2) To assess the relationship between longitudinal WMH accumulation and last MRI MCH during the double-blind phase of the A4 trial.DesignA multicenter, randomized, double-blind, placebo-controlled, Phase 3 study comparing solanezumab with placebo given as infusions once every 4 weeks over 4.5 years in subjects with preclinical AD, defined as having evidence of elevated brain amyloid before the stage of clinically evident cognitive impairment, with an optional open-label extension period.SettingAnti-Amyloid Treatment in Asymptomatic Alzheimer’s Disease (A4) study.ParticipantsA sample of 1157 cognitively unimpaired older adults (mean age = 71.9 years [SD = 4.8 years], 59% women, 59% APOE ε4 carriers).MeasurementsA linear regression model was used to assess the impact of baseline MCH amount (0, 1, 2+) on WMH volume. A linear mixed-effects model was used to assess the impact of last MRI MCH on longitudinal WMH. All models were corrected for age, sex, grey matter volume, cortical amyloid PET, APOE ε4 status, and treatment group.ResultsBaseline WMH volume was greater in individuals with more than one MCH compared to those with no MCH (t=4.8, p<0.001). The longitudinal increase in WMH amongst individuals with one (t=2.3, p=0.025) and more than one MCH (t=6.7, p<0.001) at the last MRI was greater than those with no MCH.ConclusionThese results indicate a strong association between WMH and MCH, a common manifestation of cerebral amyloid angiopathy and ARIA-H. These results suggest that increased WMH volume may represent an early sign of vessel amyloidosis, likely prior to the emergence of MCH.

Correlation between matrix metalloproteinase-2, matrix metalloproteinase-9, and tissue inhibitor of metalloproteinases-1 and white matter hyperintensities in patients with cerebral small vessel disease based on cranial magnetic resonance 3D imaging

ObjectiveThe objective of this study was to investigate the correlation between serum levels of matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinases-1 (TIMP-1) levels and their ratios with the severity of white matter hyperintensities (WMHs) in patients with cerebral small vessel disease (CSVD). MethodsThis cross-sectional study was done on a prospective cohort of patients with CSVD. Qualitative and quantitative analyses of WMHs were performed using Fazekas grading and lesion prediction algorithm (LPA) methods. Biomarkers MMP-2, MMP-9, and TIMP-1 were measured to explore their correlation with the severity of WMHs. ResultsThe sample consisted of 144 patients with CSVD. There were 63 male and 81 female patients, with an average age of 67.604 ± 8.727 years. Among these, 58.33% presented with white matter hyperintensities at Fazekas grading level 1, with an average total template volume of WMHs of 4.305 mL. MMP-2 (P = 0.025), MMP-9 (P = 0.008), TIMP-1 (P = 0.026), and age (P = 0.007) were identified as independent correlates of WMHs based on Fazekas grading. Independent correlates of the total template volume of WMHs included MMP-2 (P = 0.023), TIMP-1 (P = 0.046), age (P = 0.047), systolic blood pressure (P = 0.047), and homocysteine (Hcy) (P = 0.014). In addition, age (P = 0.003; P < 0.001), interleukin-6 (IL-6) (P < 0.001; P = 0.044), Hcy (P < 0.001; P < 0.001), glycated hemoglobin (HbA1c) (P = 0.016; P = 0.043), and chronic kidney disease (P < 0.001; P < 0.001) were associated with both WMHs Fazekas grading and the total template volume of WMHs. ConclusionSerum levels of MMP-9, MMP-2, and TIMP-1 were independently associated with the Fazekas grading, while serum TIMP-1 and MMP-2 levels were independently related to the total template volume of WMHs. The association of TIMP-1 and MMP-2 with the severity of CSVD-related WMHs suggests their potential role as disease-related biomarkers. However, further research is required to uncover the specific mechanisms underlying these interactions.