Cerebral Microbleeds and White Matter Hyperintensities are Associated with Cognitive Decline in an Asian Memory Clinic Study

Linking peripheral atherosclerosis to blood-brain barrier disruption: elucidating its role as a manifestation of cerebral small vessel disease in vascular cognitive impairment

Aging plays a pivotal role in the pathogenesis of cerebral small vessel disease (CSVD), contributing to the onset and progression of vascular cognitive impairment and dementia (VCID). In older adults, CSVD often leads to significant pathological outcomes, including blood-brain barrier (BBB) disruption, which in turn triggers neuroinflammation and white matter damage. This damage is frequently observed as white matter hyperintensities (WMHs) in neuroimaging studies. There is mounting evidence that older adults with atherosclerotic vascular diseases, such as peripheral artery disease, ischemic heart disease, and carotid artery stenosis, face a heightened risk of developing CSVD and VCID. This review explores the complex relationship between peripheral atherosclerosis, the pathogenesis of CSVD, and BBB disruption. It explores the continuum of vascular aging, emphasizing the shared pathomechanisms that underlie atherosclerosis in large arteries and BBB disruption in the cerebral microcirculation, exacerbating both CSVD and VCID. By reviewing current evidence, this paper discusses the impact of endothelial dysfunction, cellular senescence, inflammation, and oxidative stress on vascular and neurovascular health. This review aims to enhance understanding of these complex interactions and advocate for integrated approaches to manage vascular health, thereby mitigating the risk and progression of CSVD and VCID.

Sporadic cerebral small vessel disease and cognitive decline in healthy older adults: A systematic review and meta-analysis

We performed a systematic review and meta-analysis on prospective studies that provided risk estimates for the impact of 3 different MRI markers of small vessel disease (SVD), namely white matter hyperintensities (WMH), cerebral microbleeds (CMB) and lacunes, on cognitive decline in relatively healthy older adults without cognitive deficits at baseline. A total of 23 prospective studies comprising 11,486 participants were included for analysis. Extracted data was pooled, reviewed and meta-analysed separately for global cognition, executive function, memory and attention. The pooled effect size for the association between cerebral SVD and cognitive decline was for global cognition -0.10 [-0.14; -0.05], for executive functioning -0.18 [-0.24; - 0.11], for memory -0.12 [-0.17; -0.07], and for attention -0.17 [-0.23; -0.11]. Results for the association of individual MRI markers of cerebral SVD were statistically significant for WMH and global cognition -0.15 [-0.24; -0.06], WMH and executive function -0.23 [-0.33; -0.13], WMH and memory -0.19 [-0.29; -0.09], WMH and attention -0.24 [-0.39; -0.08], CMB and executive function -0.07 [-0.13; -0.02], CMB and memory -0.11 [-0.21; -0.02] and CMB and attention -0.13 [-0.25; -0.02]. In conclusion, presence of MRI markers of cerebral SVD were found to predict an increased risk of cognitive decline in relatively healthy older adults. While WMH were found to significantly affect all cognitive domains, CMB influenced decline in executive functioning over time as well as (in some studies) decline in memory and attention.

Association of plasma GFAP with elevated brain amyloid is dependent on severity of white matter lesions in an Asian cognitively impaired cohort

INTRODUCTION

While elevated blood glial fibrillary acidic protein (GFAP) has been associated with brain amyloid pathology, whether this association occurs in populations with high cerebral small vessel disease (CSVD) concomitance remains unclear.

METHODS

Using a Singapore-based cohort of cognitively impaired subjects, we assessed associations between plasma GFAP and neuroimaging measures of brain amyloid and CSVD, including white matter hyperintensities (WMH). We also examined the diagnostic performance of plasma GFAP in detecting brain amyloid beta positivity (Aβ+).

RESULTS

When stratified by WMH status, elevated brain amyloid was associated with higher plasma GFAP only in the WMH- group (β = 0.383; P < 0.001). The diagnostic performance of plasma GFAP in identifying Aβ+ was significantly higher in the WMH- group (area under the curve [AUC] = 0.896) than in the WMH+ group (AUC = 0.712, P = 0.008).

DISCUSSION

The biomarker utility of plasma GFAP in detecting brain amyloid pathology is dependent on the severity of concomitant WMH.

Highlight

Glial fibrillary acidic protein (GFAP)'s association with brain amyloid is unclear in populations with high cerebral small vessel disease (CSVD).Plasma GFAP was measured in a cohort with CSVD and brain amyloid.Plasma GFAP was better in detecting amyloid in patients with low CSVD versus high CSVD.Biomarker utility of GFAP in detecting brain amyloid depends on the severity of CSVD.

Blood-based biomarkers of cerebral small vessel disease

Age-associated cerebral small vessel disease (CSVD) represents a clinically heterogenous condition, arising from diverse microvascular mechanisms. These lead to chronic cerebrovascular dysfunction and carry a substantial risk of subsequent stroke and vascular cognitive impairment in aging populations. Owing to advances in neuroimaging, in vivo visualization of cerebral vasculature abnormities and detection of CSVD, including lacunes, microinfarcts, microbleeds and white matter lesions, is now possible, but remains a resource-, skills- and time-intensive approach. As a result, there has been a recent proliferation of blood-based biomarker studies for CSVD aimed at developing accessible screening tools for early detection and risk stratification. However, a good understanding of the pathophysiological processes underpinning CSVD is needed to identify and assess clinically useful biomarkers. Here, we provide an overview of processes associated with CSVD pathogenesis, including endothelial injury and dysfunction, neuroinflammation, oxidative stress, perivascular neuronal damage as well as cardiovascular dysfunction. Then, we review clinical studies of the key biomolecules involved in the aforementioned processes. Lastly, we outline future trends and directions for CSVD biomarker discovery and clinical validation.

Contributions of amyloid beta and cerebral small vessel disease in clinical decline

INTRODUCTION

We assessed whether co-morbid small vessel disease (SVD) has clinical predictive value in preclinical or prodromal Alzheimer's disease.

METHODS

In 1090 non-demented participants (65.4 ± 10.7 years) SVD was assessed with magnetic resonance imaging and amyloid beta (Aβ) with lumbar puncture and/or positron emission tomography scan (mean follow-up for cognitive function 3.1 ± 2.4 years).

RESULTS

Thirty-nine percent had neither Aβ nor SVD (A-V-), 21% had SVD only (A-V+), 23% Aβ only (A+V-), and 17% had both (A+V+). Pooled cohort linear mixed model analyses demonstrated that compared to A-V- (reference), A+V- had a faster rate of cognitive decline. Co-morbid SVD (A+V+) did not further increase rate of decline. Cox regression showed that dementia risk was modestly increased in A-V+ (hazard ratio [95% confidence interval: 1.8 [1.0-3.2]) and most strongly in A+ groups. Also, mortality risk was increased in A+ groups.

DISCUSSION

In non-demented persons Aβ was predictive of cognitive decline, dementia, and mortality. SVD modestly predicts dementia in A-, but did not increase deleterious effects in A+.

HIGHLIGHTS

Amyloid beta (Aβ; A) was predictive for cognitive decline, dementia, and mortality. Small vessel disease (SVD) had no additional deleterious effects in A+. SVD modestly predicted dementia in A-. Aβ should be assessed even when magnetic resonance imaging indicates vascular cognitive impairment.

Risk Factor Analysis in Patients Exhibiting Cerebral Microbleeds and the Correlation with Cognitive Impairment

Objective: To identify the risk factors contributing to cerebral microbleeds (CMBs), analyze the correlation between the quantity and distribution of CMBs and overall cognitive performance, including specific cognitive domains in patients, and investigate the underlying mechanisms by which CMBs impact cognitive function. Methods: Patients diagnosed with cerebral small vessel disease were recruited between September 2022 and September 2023. Clinical baseline data were systematically gathered. The Montreal Cognitive Assessment (MoCA) was employed to evaluate patients' cognitive status. CMBs were identified via susceptibility-weighted imaging (SWI), noting their locations and quantities. Patients were categorized into two cohorts: those without CMBs and those with CMBs. This division facilitated the comparison of basic clinical data and laboratory indicators, aiming to elucidate the risk factors associated with CMBs. Within the CMBs cohort, patients were further classified based on the number of CMBs into mild, moderate, and severe groups, and according to CMBs' locations into deep, cortical-subcortical, and mixed groups. Spearman correlation analysis and ANOVA were utilized to compare the total MoCA scores, as well as scores in specific cognitive domains, across these groups. This approach enabled the analysis of the relationship between the quantity and location of CMBs and cognitive impairment. Results: Statistically significant differences were noted between patients with and without cerebral microbleeds (CMBs) regarding gender, age, hypertension, diabetes, history of cerebral infarction, history of alcohol consumption, glycosylated hemoglobin levels, low-density lipoprotein cholesterol, and homocysteine levels (p < .05). Multifactorial logistic regression analysis identified age, hypertension, diabetes, history of alcohol consumption, and elevated homocysteine as independent risk factors for the development of CMBs. Spearman correlation analysis revealed a linear correlation between the presence of CMBs and the total score of the MoCA (r = -.837, p < .001). The group with CMBs demonstrated a significant decline in visuospatial execution function and delayed recall abilities compared to the group without CMBs (p < .05). Specifically, deep CMBs were linked to impairments in visuospatial execution function, naming, attention, computational ability, language, delayed recall, and orientation (p < .05). Cortical-subcortical CMBs affected visuospatial execution function, attention, computational ability, and delayed recall ability(p < .05). Mixed CMBs impacted visuospatial execution function and naming (p < .05). Conclusion: Age, hypertension, diabetes, history of alcohol consumption, and elevated homocysteine levels are key independent risk factors for CMBs. There exists a linear relationship between the severity of CMBs and the extent of cognitive impairment. Patients with CMBs show notable deterioration in visuospatial execution function and delayed recall abilities. Furthermore, the location of CMBs influences various specific cognitive domains.

Neurologic Effects of SARS-CoV-2 Transmitted among Dogs

SARS-CoV-2 induces illness and death in humans by causing systemic infections. Evidence suggests that SARS-CoV-2 can induce brain pathology in humans and other hosts. In this study, we used a canine transmission model to examine histopathologic changes in the brains of dogs infected with SARS-CoV-2. We observed substantial brain pathology in SARS-CoV-2-infected dogs, particularly involving blood-brain barrier damage resembling small vessel disease, including changes in tight junction proteins, reduced laminin levels, and decreased pericyte coverage. Furthermore, we detected phosphorylated tau, a marker of neurodegenerative disease, indicating a potential link between SARS-CoV-2-associated small vessel disease and neurodegeneration. Our findings of degenerative changes in the dog brain during SARS-CoV-2 infection emphasize the potential for transmission to other hosts and induction of similar signs and symptoms. The dynamic brain changes in dogs highlight that even asymptomatic individuals infected with SARS-CoV-2 may develop neuropathologic changes in the brain.

Magnetic resonance imaging and neuropsychological findings for predicting of cognitive deterioration in memory clinic patients

Objective

The severity of cerebral small vessel disease (SVD) on magnetic resonance imaging (MRI) has been assessed using hypertensive arteriopathy SVD and cerebral amyloid angiopathy (CAA)-SVD scores. In addition, we reported the modified CAA-SVD score including cortical microinfarcts and posterior dominant white matter hyperintensity. Each SVD score has been associated with cognitive function, but the longitudinal changes remain unclear. Therefore, this study prospectively examined the prognostic value of each SVD score, imaging findings of cerebral SVD, and neuropsychological assessment.

Methods

This study included 29 patients diagnosed with mild cognitive impairment or mild dementia at memory clinic in our hospital, who underwent clinical dementia rating (CDR) and brain MRI (3D-fluid attenuated inversion recovery, 3D-double inversion recovery, and susceptibility-weighted imaging) at baseline and 1 year later. Each SVD score and neuropsychological tests including the Mini-Mental State Examination, Japanese Raven's Colored Progressive Matrices, Trail Making Test -A/-B, and the Rivermead Behavioral Memory Test were evaluated at baseline and 1 year later.

Results

Twenty patients had unchanged CDR (group A), while nine patients had worsened CDR (group B) after 1 year. At baseline, there was no significant difference in each SVD score; after 1 year, group B had significantly increased CAA-SVD and modified CAA-SVD scores. Group B also showed a significantly higher number of lobar microbleeds than group A at baseline. Furthermore, group B had significantly longer Japanese Raven's Colored Progressive Matrices and Trail Making test-A times at baseline. After 1 year, group B had significantly lower Mini-Mental State Examination, Japanese Raven's Colored Progressive Matrices, and Rivermead Behavioral Memory Test scores and significantly fewer word fluency (letters).

Conclusion

Patients with worsened CDR 1 year after had a higher number of lobar microbleeds and prolonged psychomotor speed at baseline. These findings may become predictors of cognitive deterioration in patients who visit memory clinics.

Elevated Soluble TNF-Receptor 1 in the Serum of Predementia Subjects with Cerebral Small Vessel Disease

Tumor necrosis factor-receptor 1 (TNF-R1)-mediated signaling is critical to the regulation of inflammatory responses. TNF-R1 can be proteolytically released into systemic blood circulation in a soluble form (sTNF-R1), where it binds to circulating TNF and functions to attenuate TNF-mediated inflammation. Increases of peripheral sTNF-R1 have been reported in both Alzheimer’s disease (AD) dementia and vascular dementia (VaD). However, the status of sTNF-R1 in predementia subjects (cognitive impairment, no dementia, CIND) is unknown, and putative associations with cerebral small vessel disease (CSVD), as well as with longitudinal changes in cognitive functions are unclear. We measured baseline serum sTNF-R1 in a longitudinally assessed cohort of 93 controls and 103 CIND, along with neuropsychological evaluations and neuroimaging assessments. Serum sTNF-R1 levels were increased in CIND compared with controls (p < 0.001). Higher baseline sTNF-R1 levels were specifically associated with lacunar infarcts (rate ratio = 6.91, 95% CI 3.19–14.96, p < 0.001), as well as lower rates of cognitive decline in the CIND subgroup. Our data suggest that sTNF-R1 interacts with vascular cognitive impairment in a complex manner at predementia stages, with elevated levels associated with more severe CSVD at baseline, but which may subsequently be protective against cognitive decline.

Increase in cerebral microbleeds and cognitive decline

BACKGROUND

In spite of increasing evidence of the clinical importance of cerebral microbleeds (CMBs), the relationship between CMBs and cognitive impairment is still controversial. In addition, there are very limited prior data regarding the prospective association of additional CMBs over time with a decline in cognitive function. This study thus aimed to investigate the effects of newly detected CMBs on cognitive decline in a Japanese health examination cohort.

PATIENTS AND METHODS

We performed a prospective cohort study involving 769 Japanese participants (mean age, 61.6 years) with a mean follow-up of 7.3 ± 3.5 years. CMBs were classified according to their locations. Cognitive functions were evaluated using Okabe's Intelligence Scale, Koh's block design test, and the Wisconsin Card Sorting Test. Multiple linear regression analyses were performed to examine the relationship between the newly detected CMBs and cognitive decline.

RESULTS

Fifty-six (7.3%) participants (16 had new strictly lobar cerebral microbleeds and 40 had new deep or infratentorial cerebral microbleeds) developed new CMBs during the follow-up period. In multivariable analysis, newly detected strictly lobar CMBs were associated with a greater decline in the Wisconsin Card Sorting Test in the categories achieved (β: - 0.862 [95% CI: - 1.325, - 0.399]; P < 0.0001), greater increase in perseverative errors of Nelson (β: 0.603 [95% CI: 0.023, 1.183]; P = 0.04), and greater increase in the difficulty with maintaining set (β: 1.321 [95% CI: 0.801, 1.842]; P < 0.0001).

CONCLUSIONS

Strictly lobar CMBs over time were associated with a decline in executive function.

Deep medullary veins: a promising neuroimaging marker for mild cognitive impairment in outpatients

BACKGROUND AND PURPOSE

Mild cognitive impairment is an age-dependent pre-dementia state caused by varied reasons. Early detection of MCI helps handle dementia. Vascular factors are vital for the occurrence of MCI. This study investigates the correlation between deep medullary veins and multi-dimensional cognitive outcomes.

MATERIALS AND METHODS

A total of 73 participants with MCI and 32 controls were enrolled. Minimum Mental State Examination and Montreal Cognitive Assessment were used to examine the global cognitive function, and different cognitive domains were measured by specific neuropsychological tests. MRI was used to assess the visibility of the DMV and other neuroimage markers.

RESULTS

DMV score was statistically significantly higher in the MCI group compared with the control group (P = 0.009) and independently related to MCI (P = 0.007). Linear regression analysis verified that DMV score was linearly related to global cognition, memory, attention, and executive function after adjusting for cerebrovascular risk factors.

CONCLUSION

DMV score was independently related to the onset of MCI, and correlates with overall cognition, memory, attention, and executive function in outpatients.

The performance of patients with cerebral microbleeds in different cognitive tests: A cross-sectional study

Background

The clinical features and pathological process of cerebral microbleed (CMB)-related cognitive impairment are hot topics of cerebral small vessel disease (CSVD). However, how to choose a more suitable cognitive assessment battery for CMB patients is still an urgent issue to be solved. This study aimed to analyze the performance of CMB patients on different cognitive tests.

Methods

This study was designed as a cross-sectional study. The five main markers of CSVD (including the CMB, white matter hyperintensities, perivascular spaces, lacunes and brain atrophy) were assessed according to magnetic resonance imaging. The burden of CMB was categorized into four grades based on the total number of lesions. Cognitive function was assessed by Mini-Mental State Examination (MMSE), Trail-Making Test (TMT, Part A and Part B), Stroop color-word test (Stroop test, Part A, B and C), Verbal Fluency Test (VF, animal), Digit-Symbol Substitution Test (DSST), Digit Cancellation Test (DCT) and Maze. Multiple linear regression analysis was conducted to analyze the association between CMB and cognitive findings.

Results

A total of 563 participants (median age of 69 years) were enrolled in this study, including 218 (38.7%) CMB patients. CMB patients showed worse performance than non-CMB subjects in each cognitive test. Correlation analysis indicated the total number of CMB lesions had positive correlations with the time of TMT, Maze and Stroop test, and negative correlations with the performance of MMSE, VF, DSST, and DCT. After the adjustment for all the potential confounders by linear regression, the CMB burden grade was correlated with the performance of VF, Stroop test C, Maze and DCT.

Conclusion

The presence of CMB lesions was associated with much worse cognitive performances. In VF, Stroop test C, Maze and DCT, the correlations between CMB severity and assessment results were more significant. Our study further confirmed that the attention/executive function domain was the most commonly evaluated in CMB, which provided a picture of the most utilized tools to analyze the prognostic and diagnostic value in CMB.

Plasma Lipoprotein-Associated Phospholipase A2 Affects Cognitive Impairment in Patients with Cerebral Microbleeds

Purpose

The plasma lipoprotein-associated phospholipase A2 (Lp-PLA2) is an inflammatory biomarker of cerebral microbleeds (CMBs) and may be related to the occurrence, development, and prognosis of cognitive impairment. The present study aimed to investigate the impact of plasma Lp-PLA2 level on the cognitive impairment in patients with CMBs.

Methods

In this study, 213 patients with CMBs confirmed by 3.0 T brain magnetic resonance imaging (MRI) were analyzed. Lp-PLA2 levels were determined by magnetic particle chemiluminescence immunoassay technology, and cognitive function was assessed using the Montreal Cognitive Assessment Scale (MoCA). The cognitive functions of patients with CMBs were divided into three groups according to the MoCA scale, including normal cognition (NC), mild cognitive impairment (MCI), and moderate-severe cognitive impairment (MSCI). Clinical, laboratory and radiological data of the three groups were analysed. The relationship between plasma Lp-PLA2 and MoCA score in patients with CMBs was investigated through rank correlation analysis and multivariate regression analysis, and receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of Lp-PLA2.

Results

CMBs were detected in 213 (30.2%) of 705 patients who underwent 3.0 T MRI. Multiple comparisons showed that plasma Lp-PLA2 in patients with CMBs with normal cognitive scores was significantly lower than that in the other two groups with cognitive impairment (p < 0.05). In the single factor correlation analysis, high level of plasma Lp-PLA2 was negatively correlated with the decrease of MoCA score in patients with CMBs (r =-0.389, p < 0.01). Multivariate regression analysis showed that high plasma Lp-PLA2 was an independent risk factor for a low MoCA score in patients with CMBs (odds ratio [OR]=1.014; 95% confidence interval [CI], 1.002-1.026; p=0.025).

Conclusion

A high level of plasma Lp-PLA2 is positively correlated with the generation of cognitive impairment in patients with CMBs and negatively correlated with the degree of impairment. Plasma Lp-PLA2 is an important indicator of cognitive impairment in patients with CMBs and may provide a therapeutic target for preventing CMB-induced cognitive impairment.

Use of Lipid-Lowering Drugs After Intracerebral Hemorrhage

Hyperlipidemia is common in patients with intracerebral hemorrhage (ICH). Accumulating evidence indicates that patients with ICH are at risk for future hemorrhage recurrence, cardiovascular disease, and ischemic stroke and highlights the importance of secondary prevention of vascular events after ICH. Although the benefits of intensive treatment of hyperlipidemia for reducing ischemic cardiac and vascular events in patients with ischemic stroke are well established, the benefit versus harm in patients with ICH are less clear. Epidemiological studies suggest that hyperlipidemia is protective against ICH and that intensive lowering of lipids is associated with increased risk for ICH. Similarly, although currently available lipid-lowering treatments have been thoroughly studied in patients with ischemic cardiac and vascular disease, only few randomized trials of these therapies included a very small number of patients with history of ICH. Thus, limiting any definitive conclusions regarding the safety and net benefit of these treatments in ICH populations. Currently, there is no consensus regarding the optimal strategy for management of hyperlipidemia after ICH. In this article, we review relevant literature to outline the competing risks and benefits of lipid-lowering treatments in this vulnerable patient population. We suggest a treatment paradigm based on available data but note that data from dedicated randomized trials are needed to build the necessary evidence to guide optimal lipid-lowering strategy in patients with a history of ICH.