Manifestations Of Small Vessel Disease Research Articles

Normative Population-Derived Data for MRI Manifestations of Cerebral Small Vessel Disease.

Cerebral small vessel disease (SVD) is manifested on magnetic resonance imaging (MRI) by white matter hyperintensities, lacunes, microbleeds, and atrophy. While these manifestations can be part of normal aging, a high burden has been associated with cognitive impairment and vascular events. Distinguishing between normal versus abnormal SVD lesion burden in clinical practice remains complex. Our objective is to establish age- and sex-specific normative data for MRI manifestations of SVD, to support clinical assessment in individual patients. We used 11 465 MRI scans from 5402 participants of the Rotterdam Study, the Netherlands, an ongoing prospective population-based cohort since 1990, to develop percentile curves for white matter hyperintensities and brain parenchymal fraction and probability curves for the prevalence and count of lacunes and microbleeds, across ages 45 to 100 years, stratified by sex. Participants were primarily White (≈97%), with a mean age at first scan of 64.7 (range, 45.7-97.9) years, and 55.7% being female participants. For all SVD MRI manifestations, the curves demonstrated nonlinear trends, with accelerating burden with advancing age (eg, doubling of white matter hyperintensity fraction every 10 years). Regarding brain parenchymal fraction, a decline was seen earlier in male participants (≈45 years) than female participants (≈60 years) and was more pronounced in male participants over time. Female participants had slightly higher white matter hyperintensity fractions compared with male participants across all ages. Lacunes and microbleeds were more frequently found in male participants than in female participants, and microbleeds were more prevalent than lacunes. We provide comprehensive normative data for different MRI manifestations of SVD, presented as percentile and probability curves by age, stratified by sex. This can aid clinicians to actually quantify the SVD burden on an individual patient's MRI scans and detect patterns of abnormality.

Epigenetic age acceleration predicts subject-specific white matter degeneration in the human brain.

Epigenetic clocks provide powerful tools for estimating health and lifespan but their ability to predict brain degeneration and neuronal damage during the aging process is unknown. In this study, we use GrimAge, an epigenetic clock correlated to several blood plasma proteins, to longitudinally investigate brain cellular microstructure in axonal white matter from a cohort of healthy aging individuals. A specific focus was made on white matter hyperintensities, a visible neurological manifestation of small vessel disease, and the axonal pathways throughout each individual's brain affected by their unique white matter hyperintensity location and volume. 98 subjects over 55 years of age were scanned at baseline with 41 returning for a follow-up scan 2 years later. Using diffusion MRI lesionometry, we reconstructed subject-specific networks of affected axonal tracts and examined the diffusion cellular microstructure composition of these areas, both at baseline and longitudinally, for evidence of cellular degeneration. A chronological age-adjusted version of GrimAge was significantly correlated with baseline WMH volume and markers of neuronal decline, indicated by increased extracellular free water, increased intracellular signal, and decreased axonal signal within WMH. By isolating subject-specific axonal regions "lesioned" by crossing through a WMH, age-adjusted GrimAge was also able to predict longitudinal development of similar patterns of neuronal decline throughout the brain. This study is the first to demonstrate WMH lesionometry as a subject-specific precision imaging technique to study degeneration in aging and the first to establish a relationship between accelerated epigenetic GrimAge and brain cellular microstructure in humans.

Associations Between CSF Markers of Inflammation, White Matter Lesions, and Cognitive Decline in Individuals Without Dementia.

Small vessel disease (SVD) and neuroinflammation both occur in Alzheimer disease (AD) and other neurodegenerative diseases. It is unclear whether these processes are related or independent mechanisms in AD, especially in the early stages of disease. We therefore investigated the association between white matter lesions (WML; the most common manifestation of SVD) and CSF biomarkers of neuroinflammation and their effects on cognition in a population without dementia. Individuals without dementia from the Swedish BioFINDER study were included. The CSF was analyzed for proinflammatory markers (interleukin [IL]-6 and IL-8), cytokines (IL-7, IL-15, and IL-16), chemokines (interferon γ-induced protein 10, monocyte chemoattractant protein 1), markers of vascular injury (soluble intercellular adhesion molecule 1, soluble vascular adhesion molecule 1), and markers of angiogenesis (placental growth factor [PlGF], soluble fms-related tyrosine kinase 1 [sFlt-1], vascular endothelial growth factors [VEGF-A and VEFG-D]), and amyloid β (Aβ)42 Aβ40, and p-tau217. WML volumes were determined at baseline and longitudinally over 6 years. Cognition was measured at baseline and follow-up over 8 years. Linear regression models were used to test associations. A total of 495 cognitively unimpaired (CU) elderly individuals and 247 patients with mild cognitive impairment (MCI) were included. There was significant worsening in cognition over time, measured by Mini-Mental State Examination, Clinical Dementia Rating, and modified preclinical Alzheimer composite score in CU individuals and patients with MCI, with more rapid worsening in MCI for all cognitive tests. At baseline, higher levels of PlGF (β = 0.156, p < 0.001), lower levels of sFlt-1 (β = -0.086, p = 0.003), and higher levels of IL-8 (β = 0.07, p = 0.030) were associated with more WML in CU individuals. In those with MCI, higher levels of PlGF (β = 0.172, p = 0.001), IL-16 (β = 0.125, p = 0.001), IL-8 (β = 0.096, p = 0.013), IL-6 (β = 0.088, p = 0.023), VEGF-A (β = 0.068, p = 0.028), and VEGF-D (β = 0.082, p = 0.028) were associated with more WML. PlGF was the only biomarker that was associated with WML independent of Aβ status and cognitive impairment. Longitudinal analyses of cognition showed independent effects of CSF inflammatory markers and WML on longitudinal cognition, especially in people without cognitive impairment at baseline. Most neuroinflammatory CSF biomarkers were associated with WML in individuals without dementia. Our findings especially highlight a role for PlGF, which was associated with WML independent of Aβ status and cognitive impairment.

Haptoglobin genotype and its relation to asymptomatic cerebral small-vessel disease in type 1 diabetes

AimCerebral small-vessel disease (SVD) is prevalent in type 1 diabetes and has been associated with the haptoglobin variant allele Hp1. Contrarily, the Hp2-allele has been linked to cardiovascular disease and the role of haptoglobin-genotype in asymptomatic SVD is unknown. We, therefore, aimed to evaluate the alleles’ association with SVD.MethodsThis cross-sectional study included 179 neurologically asymptomatic adults with type 1 diabetes (women 53%, mean age 39 ± 7 years, diabetes duration 23 ± 10 years, HbA1c 8.1 ± 3.2% [65 ± 12 mmol/mol]). Examinations included genotyping (genotypes Hp1-1, Hp2-1, Hp2-2) by polymerase chain reaction, clinical investigation, and magnetic resonance brain images assessed for SVD manifestations (white matter hyperintensities, cerebral microbleeds, and lacunar infarcts).ResultsSVD prevalence was 34.6%. Haptoglobin genotype frequencies were 15.6% (Hp1-1), 43.6% (Hp1-2), and 40.8% (Hp2-2). Only diastolic blood pressure differed between the genotypes Hp1-1, Hp1-2, and Hp2-2 (81 [74–83], 75 [70–80], and 75 [72–81] mmHg, p = 0.019). Haptoglobin genotype frequencies by presence versus absence of SVD were 16.1%; 46.8%; 37.1% versus 15.4%; 41.9%; 42.7% (p = 0.758). Minor allele frequencies were 39.5% versus 36.3% (p = 0.553). Hp1 homozygotes and Hp2 carriers displayed equal proportions of SVD (35.7% vs 34.4%, p > 0.999) and SVD manifestations (white matter hyperintensities 14.3% vs 17.9%, p = 0.790; microbleeds 25.0% vs 21.9%, p = 0.904; lacunar infarcts 0% vs 3.6%, p > 0.999). Hp1-1 was not associated with SVD (OR 1.19, 95% CI 0.46–2.94, p = 0.712) when adjusting for age, blood pressure, and diabetic retinopathy.ConclusionsAlthough the SVD prevalence was high, we detected no significant association between SVD and haptoglobin-genotype.

Abstract TP21: Association Of Periodontal Disease And Small Vessel Disease In Stroke And Transient Ischemic Attack Patients

Introduction: Few studies have systematically investigated the association between periodontal disease (PD) and small vessel disease (SVD) in stroke/TIA patients. White matter hyperintensity (WMH) is a manifestation of SVD in the brain and is a surrogate for vascular cognitive impairment. Methods: Consecutive stroke/TIA patients admitted to our tertiary stroke center were assessed for PD as a part of a stroke study. PD was defined as moderate/severe periodontitis by Center for Disease Control/American Academy of Periodontology Working Group. Periventricular (PVWMH) and deep white matter (DWMH) were rated visually on axial FLAIR imaging using the 4-point Fazeka scale and were categorized into none/mild (grades 0-1) or moderate/severe (grades 2-3). Total WMHs were dichotomized into none/mild (grades 0-2) or moderate/severe (grades 3-6). Student t-tests were performed to test continuous variables, and X 2 test was used to compare categorical variables. Multivariable analysis was conducted using multiple logistic regression to test the association between PD and WMH. Results: A total of 861 consecutive patients, 404 with PD and 457 without PD, were compared for moderate/severe PVWMH and DWMH. Patients with PD were more likely to be African American (AA) compared to whites (55% vs. 36%, p&lt;0.001). They were also more likely to be smokers (62% vs. 42%, p&lt;0.001). Patients with PD were similar in age (63.7±12.0 vs. 63.4 ± 12.8), gender, hypertension, diabetes, hyperlipidemia, and atrial fibrillation status. PD was associated with total WMH (OR 1.51, 95% 1.14-2.00) and DWMH (OR 1.46, 95% 1.08-1.97). PD was not significantly associated with PVWMH (OR 1.30, 95% 0.98-1.73). These associations remained significant after adjusting for age, gender, race, hypertension, diabetes, and smoking for total WMH (Adj. OR 1.38, 95% 1.01-1.88) and DWMH (Adj. OR 1.37, 95% 1.00-1.90) and remained nonsignificant for PVWMH (Adj. OR 1.24, 95% 0.91-1.70). Conclusion: Stroke/TIA patients with PD were more likely to be AA and smokers. We report significant independent associations of PD with total WMH and DWMH manifestations of SVD. This suggests that stroke risk in AA and smokers may be partly mediated by SVD.

5-Year Associations among Cerebral Arterial Pulsatility, Perivascular Space Dilation, and White Matter Lesions.

High cerebral arterial pulsatility index (PI), white matter lesions (WMLs), enlarged perivascular spaces (PVSs), and lacunar infarcts are common findings in the elderly population, and considered indicators of small vessel disease (SVD). Here, we investigate the potential temporal ordering among these variables, with emphasis on determining whether high PI is an early or delayed manifestation of SVD. In a population-based cohort, 4D flow MRI data for cerebral arterial pulsatility was collected for 159 participants at baseline (age 64-68), and for 122 participants at follow-up 5 years later. Structural MRI was used for WML and PVS segmentation, and lacune identification. Linear mixed-effects (LME) models were used to model longitudinal changes testing for pairwise associations, and latent change score (LCS) models to model multiple relationships among variables simultaneously. Longitudinal 5-year increases were found for WML, PVS, and PI. Cerebral arterial PI at baseline did not predict changes in WML or PVS volume. However, WML and PVS volume at baseline predicted 5-year increases in PI. This was shown for PI increases in relation to baseline WML and PVS volumes using LME models (R 0.24; p < 0.02 and R 0.23; p < 0.03, respectively) and LCS models ( =0.28; p=0.015 and =0.28; p=0.009, respectively). Lacunes at baseline were unrelated to PI. In healthy older adults, indicators of SVD are related in a lead-lag fashion, in which the expression of WML and PVS precedes increases in cerebral arterial PI. Hence, we propose that elevated PI is a relatively late manifestation, rather than a risk factor, for cerebral SVD. ANN NEUROL 2022;92:871-881.

Abstract 70: Racial Differences In Small Vessel Disease Measured In MRI Of Stroke/ TIA Patients

Introduction: White matter hyperintensities (WMH) and cerebral microbleeds (CMB) are manifestations of small vessel disease (SVD), a surrogate for vascular cognitive impairment. Few studies have systematically investigated the racial differences in SVD among African American (AA) and white stroke/TIA patients. Methods: MRI scans of consecutive ischemic stroke and TIA patients admitted to our tertiary stroke center were assessed as a part of a stroke study. Deep and periventricular WMHs (DWMHs and PVWMHs, respectively) were rated visually on axial FLAIR images using the 4-point Fazekas scale and categorized into none/mild (grades 0 and 1) or moderate/severe (grades 2 and 3). Subsequently T2*-weighted MRI scans for the number, location, and topography of CMBs, as well as patients’ demographic, clinical information, and periodontal disease (PD) were evaluated. Student t-tests were performed to test continuous variables. X 2 tests were used to compare categorical variables. Multivariable analysis using multiple logistic regression was used to test the association between AA and SVD. Results: Among a total of 861 consecutive patients (741 stroke, 120 TIA), 469 AA patients were compared with 360 white for moderate/severe PVWMH (38%), DWMH (32%) and CMB≥5 (3%). Those with moderate/severe PVWMH were older (age 68±11 vs. 61±12, p&lt;0.001), more likely to be male (42% vs. 35%, p=0.02), hypertensive (40% vs. 26%, p=0.02), diabetic (43% vs. 34%, p=0.007), and have severe PD (41% vs. 35%, p=0.07). AA race was associated with PVWMH (Adj. OR 1.9, 95% 1.4-2.7) when adjusted for age, gender, hypertension, diabetes, and PD. Those with moderate/severe DWMH were older (age 68±10 vs. 62±13, p&lt;0.001), and more likely to be hypertensive (33% vs. 24%, p=0.09), diabetic (37% vs. 27%, p=0.003), and have severe PD (36% vs. 28%, p=0.01). AA race was associated with DWMH (Adj. OR 1.5, 95% 1.1-2.2) when adjusted for age, hypertension, diabetes, and PD. Those with CMB≥5 were more likely to be hypertensive (5% vs. 1%, p=0.008). AA race was associated with CMB≥5 (Adj. OR 4.1, 95% 1.3-12.6) when adjusted for age and hypertension. Conclusion: We report significant independent association between AA race and various manifestations of SVD including moderate/severe DWMH, PVWMH, and CMB≥5.

Neuropathology of Vascular Brain Health: Insights From Ex Vivo Magnetic Resonance Imaging-Histopathology Studies in Cerebral Small Vessel Disease.

Sporadic cerebral small vessel disease (SVD) is a major contributor to vascular cognitive impairment and dementia in the aging human brain. On neuropathology, sporadic SVD is characterized by abnormalities to the small vessels of the brain predominantly in the form of cerebral amyloid angiopathy and arteriolosclerosis. These pathologies frequently coexist with Alzheimer disease changes, such as plaques and tangles, in a single brain. Conversely, during life, magnetic resonance imaging (MRI) only captures the larger manifestations of SVD in the form of parenchymal brain abnormalities. There appears to be a major knowledge gap regarding the underlying neuropathology of individual MRI-detectable SVD abnormalities. Ex vivo MRI in postmortem human brain tissue is a powerful tool to bridge this gap. This review summarizes current insights into the histopathologic correlations of MRI manifestations of SVD, their underlying cause, presumed pathophysiology, and associated secondary tissue injury. Moreover, we discuss the advantages and limitations of ex vivo MRI-guided histopathologic investigations and make recommendations for future studies.

Interactions Between Kidney Function and Cerebrovascular Disease: Vessel Pathology That Fires Together Wires Together.

The kidney and the brain, as high-flow end organs relying on autoregulatory mechanisms, have unique anatomic and physiological hemodynamic properties. Similarly, the two organs share a common pattern of microvascular dysfunction as a result of aging and exposure to vascular risk factors (e.g., hypertension, diabetes and smoking) and therefore progress in parallel into a systemic condition known as small vessel disease (SVD). Many epidemiological studies have shown that even mild renal dysfunction is robustly associated with acute and chronic forms of cerebrovascular disease. Beyond ischemic SVD, kidney impairment increases the risk of acute cerebrovascular events related to different underlying pathologies, notably large artery stroke and intracerebral hemorrhage. Other chronic cerebral manifestations of SVD are variably associated with kidney disease. Observational data have suggested the hypothesis that kidney function influences cerebrovascular disease independently and adjunctively to the effect of known vascular risk factors, which affect both renal and cerebral microvasculature. In addition to confirming this independent association, recent large-scale human genetic studies have contributed to disentangling potentially causal associations from shared genetic predisposition and resolving the uncertainty around the direction of causality between kidney and cerebrovascular disease. Accelerated atherosclerosis, impaired cerebral autoregulation, remodeling of the cerebral vasculature, chronic inflammation and endothelial dysfunction can be proposed to explain the additive mechanisms through which renal dysfunction leads to cerebral SVD and other cerebrovascular events. Genetic epidemiology also can help identify new pathological pathways which wire kidney dysfunction and cerebral vascular pathology together. The need for identifying additional pathological mechanisms underlying kidney and cerebrovascular disease is attested to by the limited effect of current therapeutic options in preventing cerebrovascular disease in patients with kidney impairment.

Cerebral Vasoreactivity Changes Over Time in Patients With Different Clinical Manifestations of Cerebral Small Vessel Disease

Objectives: Endothelial dysfunction (ED) has been linked to the pathogenesis of cerebral small vessel disease (SVD). We aimed to assess ED and cerebrovascular reactivity (CVR) in the patients with a diverse manifestation of SVD, with similar and extensive white matter lesions (WMLs, modified Fazekas scale grade ≥2), compared with a control group (CG) without the MRI markers of SVD, matched for age, gender, hypertension, diabetes, and to evaluate the change of CVR following 24 months.Methods: We repeatedly measured the vasomotor reactivity reserve (VMRr) and breath-holding index (BHI) of the middle cerebral artery (MCA) by the transcranial Doppler ultrasound (TCD) techniques in 60 subjects above 60 years with a history of lacunar stroke (LS), vascular dementia (VaD), or parkinsonism (VaP) (20 in each group), and in 20 individuals from a CG.Results: The mean age, frequency of the main vascular risk factors, and sex distribution were similar in the patients with the SVD groups and a CG. The VMRr and the BHI were more severely impaired at baseline (respectively, 56.7 ± 18% and 0.82 ± 0.39) and at follow-up (respectively, 52.3 ± 16.7% and 0.71 ± 0.38) in the patients with SVD regardless of the clinical manifestations (ANOVA, p > 0.1) than in the CG (respectively, baseline VMRr 77.2 ± 15.6%, BHI 1.15 ± 0.47, p < 0.001; follow-up VMRr 74.3 ± 17.6%, BHI 1.11 ± 0.4, p < 0.001). All the assessed CVR measures (VMRr and BHI) significantly decreased over time in the subjects with SVD (Wilcoxon's signed-rank test p = 0.01), but this was not observed in the CG (p > 0.1) and the decrease of CVR measures was not related to the SVD radiological progression (p > 0.1).Conclusions: This study provided evidence that the change in CVR measures is detectable over a 24-month period in patients with different clinical manifestations of SVD. Compared with the patients in CG with similar atherothrombotic risk factors, all the CVR measures (BMRr and BHI) significantly declined over time in the subjects with SVD. The reduction in CVR was not related to the SVD radiological progression.

Early markers and predictors of cerebrovascular diseases in a group of young and middle-aged employees of the EMERCOM of Russia

Introduction. Typical basis of chronic cerebral ischemia in young people is small vessel disease (SVD) diagnosed by micro-focal lesions and microstructural damage of cerebral white matter (WM), reduction of fractional anisotropy (FA) in diffusion tensor MRI (DT-MRI). Previous studies showed that increased dopplerographic pulsatility and resistivity indices in middle cerebral artery (MCA PI-RI) correlated with SVD manifestations and cognitive impairment in middle-aged and elderly patients. Aim – to determine early markers and predictors of asymptomatic SVD in young and middle-aged individuals without cognitive impairment. Materials and methods. 52 male employees of the EMERCOM, 47.3±7.6 years, without neurological or cognitive deficits were examined. Duplex scanning with MCA PI-RI calculation, MRI with WM damage assessment according to Fazekas scale, DT-MRI FA definition were completed. Results. All those examed showed MRI signs of SVD. Two groups were formed according to Fazekas: 0 points (n-38) and 1-2 points (n-14). The 2nd group showed higher MCA PI-RI (p&lt;0.002 and p&lt;0.05). Multivariate logistical regression analysis showed significant correlation of PI in MCA (OR: 2.33; 95% CI: 1.13- 4.81; p=0.02) with WM lesion according to Fazekas. The FA in cognitively important tracts was lower in group 2 (p&lt;0,001). A stepwise multiple linear regression model revealed that the strongest predictors of FA reduction were PI and RI. The values of psychomotor speed and attention span were lower in group 2. Conclusion. MCA PI-RI are early markers of focal lesions and microstructural changes in WM and predictors of cognitive impairment in the young and middle-aged with asymptomatic SVD.

Intracranial Atherosclerotic Burden and Cerebral Parenchymal Changes at 7T MRI in Patients With Transient Ischemic Attack or Ischemic Stroke.

The relevance of intracranial vessel wall lesions detected with MRI is not fully established. In this study (trial identification number: NTR2119; www.trialregister.nl), 7T MRI was used to investigate if a higher vessel wall lesion burden is associated with more cerebral parenchymal changes in patients with ischemic stroke or transient ischemic attack (TIA). MR images of 82 patients were assessed for the number of vessel wall lesions of the large intracranial arteries and for cerebral parenchymal changes, including the presence and number of cortical, small subcortical, and deep gray matter infarcts; lacunes of presumed vascular origin; cortical microinfarcts; and periventricular and deep white matter hyperintensities (WMHs). Regression analyses showed that a higher vessel wall lesion burden was associated with the presence of small subcortical infarcts, lacunes of presumed vascular origin, and deep gray matter infarcts (relative risk 1.18; 95% CI, 1.03–1.35) and presence of moderate-to-severe periventricular WMHs (1.21; 95% CI, 1.03–1.42), which are all manifestations of small vessel disease (SVD). The burden of enhancing vessel wall lesions was associated with the number of cortical microinfarcts only (1.48; 95% CI, 1.04–2.11). These results suggest an interrelationship between large vessel wall lesion burden and cerebral parenchymal manifestations often linked to SVD or, alternatively, that vascular changes occur in both large and small intracranial arteries simultaneously.

Modified cerebral small vessel disease score is associated with vascular cognitive impairment after lacunar stroke.

We conducted a cross-sectional study to characterize the relationship between total and modified small vessel disease (SVD) score with vascular cognitive impairment (VCI). Patients (n = 157) between the ages of 50 and 85 years old who had suffered their first lacunar infarction were analyzed prospectively. Brain magnetic resonance imaging was performed to identify SVD manifestations, which were used to calculate total or modified SVD scores. Neuropsychological assessments measured cognitive function. Spearman correlation analysis demonstrated that the total and modified SVD scores were associated with overall cognition as well as with function in the executive and visuospatial domains. The associations remained significant in linear regression after adjusting for age, sex, education and vascular risk factors. Binary logistic regression and chi-squared trend tests revealed that VCI risk increased significantly with SVD burden based on the modified SVD score. Subsequent chi-squared testing demonstrated that the VCI rate was significantly higher in patients with a modified SVD score of 5-6 than in patients without any SVD burden. Our results suggest that both the total and modified SVD scores show a negative association with cognitive function, but the modified SVD score may be better at identifying patients at high VCI risk.

Cerebrospinal Fluid Metals and the Association with Cerebral Small Vessel Disease.

Brain metal homeostasis is essential for brain health, and deregulation can result in oxidative stress on the brain parenchyma. Our objective in this study was to focus on two hemorrhagic MRI manifestations of small vessel disease [cerebral microbleeds (CMBs) and cortical superficial siderosis (cSS)] and associations with cerebrospinal fluid (CSF) iron levels. In addition, we aimed to analyze CSF biomarkers for dementia and associations with CSF metal levels. This is a cross-sectional study of 196 patients who underwent memory clinic investigation, including brain MRI. CSF was collected and analyzed for metals, amyloid-β (Aβ) 42, total tau (T-tau), and phosphorylated tau (P-tau), and CSF/serum albumin ratios. Statistical analyses were performed using generalized linear models. No significant difference was found between CSF metal levels across diagnostic groups. Higher iron and copper levels were associated with higher CSF levels of Aβ42, T-tau, P-tau, and CSF/serum albumin ratios (p < 0.05). Zinc was associated with higher CSF/serum albumin ratios. There was no significant association between CMBs or cSS and CSF iron levels. An increase in CSF iron with the number of CMBs was seen in APOEɛ4 carriers. CSF iron levels are elevated with cerebral microbleeds in APOEɛ4 carriers, with no other association seen with hemorrhagic markers of small vessel disease. The association of elevated CSF iron and copper with tau could represent findings of increased neurodegeneration in these patients.

Author response: WMH and long-term outcomes in ischemic stroke: A systematic review and meta-analysis.

We thank Dr. Gupta for the interest in our article1 and for raising important issues about alternative causes of white matter hyperintensities (WMH) other than small vessel disease (SVD). Indeed, migraine, hypertensive encephalopathy, eclampsia, and therapy with immunomodulatory agents may cause temporary WMH lesions. Yet, the prevalence of WMH lesions in the general population increases substantially with age because of the increasing underlying burden of SVD.2,3 In our article, we refer to WMH in a specific population of patients with ischemic stroke. Given the relatively old age and the high burden of vascular risk factors of this population, we believe that most WMH lesions in the original studies entered our meta-analysis to represent manifestations of SVD.

Genetic determinants of blood lipids and cerebral small vessel disease: role of high-density lipoprotein cholesterol.

Blood lipids are causally involved in the pathogenesis of atherosclerosis, but their role in cerebral small vessel disease remains largely elusive. Here, we explored associations of genetic determinants of blood lipid levels, lipoprotein particle components, and targets for lipid-modifying drugs with small vessel disease phenotypes. We selected genetic instruments for blood levels of high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides, for cholesterol and triglycerides components of size-defined lipoprotein particles, and for lipid-modifying drug targets based on published genome-wide association studies (up to 617 303 individuals). Applying two-sample Mendelian randomization approaches we investigated associations with ischaemic and haemorrhagic manifestations of small vessel disease [small vessel stroke: 11 710 cases, 287 067 controls; white matter hyperintensities (WMH): 10 597 individuals; intracerebral haemorrhage: 1545 cases, 1481 controls]. We applied the inverse-variance weighted method and multivariable Mendelian randomization as our main analytical approaches. Genetic predisposition to higher HDL-C levels was associated with lower risk of small vessel stroke [odds ratio (OR) per standard deviation = 0.85, 95% confidence interval (CI) = 0.78-0.92] and lower WMH volume (β = -0.07, 95% CI = -0.12 to -0.02), which in multivariable Mendelian randomization remained stable after adjustments for LDL-C and triglycerides. In analyses of lipoprotein particle components by size, we found these effects to be specific for cholesterol concentration in medium-sized high-density lipoprotein, and not large or extra-large high-density lipoprotein particles. Association estimates for intracerebral haemorrhage were negatively correlated with those for small vessel stroke and WMH volume across all lipid traits and lipoprotein particle components. HDL-C raising genetic variants in the gene locus of the target of CETP inhibitors were associated with lower risk of small vessel stroke (OR: 0.82, 95% CI = 0.75-0.89) and lower WMH volume (β = -0.08, 95% CI = -0.13 to -0.02), but a higher risk of intracerebral haemorrhage (OR: 1.64, 95% CI = 1.26-2.13). Genetic predisposition to higher HDL-C, specifically to cholesterol in medium-sized high-density lipoprotein particles, is associated with both a lower risk of small vessel stroke and lower WMH volume. These analyses indicate that HDL-C raising strategies could be considered for the prevention of ischaemic small vessel disease but the net benefit of such an approach would need to be tested in a randomized controlled trial.

Clinical Relevance of Cerebral Small Vessel Diseases.

Clinical Relevance of Cerebral Small Vessel Diseases.

Tolerability, safety and intermediary pharmacological effects of cilostazol and isosorbide mononitrate, alone and combined, in patients with lacunar ischaemic stroke: The LACunar Intervention-1 (LACI-1) trial, a randomised clinical trial

BackgroundLacunar stroke, a frequent clinical manifestation of small vessel disease (SVD), differs pathologically from other ischaemic stroke subtypes and has no specific long-term secondary prevention. Licenced drugs, isosorbide mononitrate (ISMN) and cilostazol, have relevant actions to prevent SVD progression. MethodsWe recruited independent patients with clinically confirmed lacunar ischaemic stroke without cognitive impairment to a prospective randomised clinical trial, LACunar Intervention-1 (LACI-1). We randomised patients using a central web-based system, 1:1:1:1 with minimisation, to masked ISMN 25 mg bd, cilostazol 100 mg bd, both ISMN and cilostazol started immediately, or both with start delayed. We escalated doses to target over two weeks, sustained for eight weeks. Primary outcome was the proportion achieving target dose. Secondary outcomes included symptoms, safety (haemorrhage, recurrent vascular events), cognition, haematology, vascular function, and neuroimaging. LACI-1 was powered (80%, alpha 0.05) to detect 35% (90% versus 55%) difference between the proportion reaching target dose on one versus both drugs at 55 patients. Registration ISRCTN12580546. FindingsLACI-1 enrolled 57 participants between March 2016 and August 2017: 18 (32%) females, mean age 66 (SD 11, range 40–85) years, onset-randomisation 203 (range 6–920) days. Most achieved full (64%) or over half (87%) dose, with no difference between cilostazol vs ISMN, single vs dual drugs. Headache and palpitations increased initially then declined similarly with dual versus single drugs. There was no between-group difference in BP, pulse-wave velocity, haemoglobin or platelet function, but pulse rate was higher (mean difference, MD, 6.4, 95%CI 1.2–11.7, p = 0.02), platelet count higher (MD 35.7, 95%CI 2.8, 68.7, p = 0.03) and white matter hyperintensities reduced more (Chi-square p = 0.007) with cilostazol versus no cilostazol. InterpretationCilostazol and ISMN are well tolerated when the dose is escalated, without safety concerns, in patients with lacunar stroke. Larger trials with longer term follow-up are justified. FundingAlzheimer's Society (AS-PG-14-033).

Endothelial damage, vascular bagging and remodeling of the microvascular bed in human microangiopathy with deep white matter lesions

White matter lesions (WMLs) are a common manifestation of small vessel disease (SVD) in the elderly population. They are associated with an enhanced risk of developing gait abnormalities, poor executive function, dementia, and stroke with high mortality. Hypoperfusion and the resulting endothelial damage are thought to contribute to the development of WMLs. The focus of the present study was the analysis of the microvascular bed in SVD patients with deep WMLs (DWMLs) by using double- and triple-label immunohistochemistry and immunofluorescence. Simultaneous visualization of collagen IV (COLL4)-positive membranes and the endothelial glycocalyx in thick sections allowed us to identify endothelial recession in different types of string vessels, and two new forms of small vessel/capillary pathology, which we called vascular bagging and ghost string vessels. Vascular bags were pouches and tubes that were attached to vessel walls and were formed by multiple layers of COLL4-positive membranes. Vascular bagging was most severe in the DWMLs of cases with pure SVD (no additional vascular brain injury, VBI). Quantification of vascular bagging, string vessels, and the density/size of CD68-positive cells further showed widespread pathological changes in the frontoparietal and/or temporal white matter in SVD, including pure SVD and SVD with VBI, as well as a significant effect of the covariate age. Plasma protein leakage into vascular bags and the white matter parenchyma pointed to endothelial damage and basement membrane permeability. Hypertrophic IBA1-positive microglial cells and CD68-positive macrophages were found in white matter areas covered with networks of ghost vessels in SVD, suggesting phagocytosis of remnants of string vessels. However, the overall vessel density was not altered in our SVD cohort, which might result from continuous replacement of vessels. Our findings support the view that SVD is a progressive and generalized disease process, in which endothelial damage and vascular bagging drive remodeling of the microvasculature.

Cerebral and Extracerebral Vasoreactivity in Patients With Different Clinical Manifestations of Cerebral Small-Vessel Disease: Data From the Significance of Hemodynamic and Hemostatic Factors in the Course of Different Manifestations of Cerebral Small-Vessel Disease Study.

Endothelial dysfunction has been implicated in the pathogenesis of cerebral small-vessel disease (SVD). Little is known about the relationship between SVD and measures of endothelium-dependent vasodilatation and cerebral vasomotor reactivity. The aim of this study was to evaluate cerebral and extracerebral endothelial dysfunction in patients with different manifestations of SVD and to assess the relationship between endothelial dysfunction and radiologic markers of SVD. The vasomotor reactivity reserve (VMRr), breath-holding index (BHI) of the middle cerebral arteries, and brachial artery flow-mediated dilatation (FMD) were measured with ultrasound techniques in 90 patients (30 in each group) older than 60 years with extensive white matter lesions (Fazekas grade ≥ 2) with a history of lacunar stroke, vascular dementia, or parkinsonism and 30 individuals with normal magnetic resonance imaging findings (control group). All groups were matched for age, sex, hypertension, and diabetes. The mean age ± SD (71.8 ± 3.4 versus 71.7 ± 3.4 years), sex distribution, and prevalence of the main vascular risk factors were similar in the SVD and control groups. The VMRr (56.6% ± 18.3% versus 77.1% ± 16.9%), BHI (0.8 ± 0.3 versus 1.1 ± 0.4), and FMD (5.8% ± 4 versus 12.1% ± 5.2%) were severely impaired in the SVD groups compared to the control group (P < .01). The vascular responses to all tests was similar in the SVD groups, but they were significantly decreased in patients with severe white matter lesions, marked brain atrophy, and enlarged perivascular spaces. This study was the first that simultaneously evaluated cerebral and extracerebral vasodilator responses in a well-phenotyped cohort of patients with lacunar stroke, vascular dementia, or parkinsonism. The VMRr, BHI, and FMD were more severely impaired in patients with SVD, regardless of its clinical manifestation, than in control participants. All measures were significantly lower in patients with severe white-matter lesions, brain atrophy, or enlarged perivascular spaces.