Association of Apolipoprotein E With Intracerebral Hemorrhage Risk by Race/Ethnicity: A Meta-analysis

APOE epsilon variants and composite risk of dementia, disability, and death in the health and retirement study

BACKGROUND

Clinical trials in older adults are increasingly focused on functional outcomes, and the composite outcome of dementia, disability, and death is gaining pivotal importance. Genetic variation, particularly the APOE epsilon(ε) variants, may modify responses to new treatments. Although APOE ε4 is known to influence these outcomes separately, the magnitude of its effect on this composite outcome remains unknown. We tested the hypothesis that APOE ε4 increases, whereas APOE ε2 decreases, the risk of a composite outcome of dementia, disability, and death.

METHODS

We evaluated clinical and genomic data from the Health and Retirement Study collected from 1992 to 2020. We used variants rs429358 and rs7412 to determine APOE genotypes, modeled dominantly (carriers/noncarriers). We conducted survival analysis, using multivariable Cox proportional hazards models with a composite endpoint of dementia, disability, and death. Our primary analysis evaluated participants with genetic data and no previous dementia or disability. In secondary analyses, we focused on persons aged > = 75 years without heart disease or stroke, a subpopulation increasingly important in clinical trials of older adults.

RESULTS

We included 14,527 participants in the primary analysis. Over a median of 18 (Interquartile Range [IQR] 12-24) years, 6711 (46%) participants developed the composite outcome. In Cox analyses, APOE ε4 associated with higher risk (HR:1.15, 95%CI:1.09-1.22) of the composite outcome, whereas APOE ε2 associated with lower risk (HR:0.92, 95%CI:0.86-0.99). In the secondary analysis, we included 3174 participants. Over a median of 7 (IQR 4-11) years, 1326 participants (42%) developed the composite outcome. In Cox analyses, APOE ε4 associated with higher risk (HR:1.25, 95%CI:1.10-1.41) of the composite outcome, whereas APOE ε2 associated with lower risk (HR:0.84, 95%CI:0.71-0.98).

CONCLUSIONS

APOE ε variants are linked to the risk of dementia, disability, and death in older adults. By examining these variants in clinical trials, we can better elucidate how they might alter the effectiveness of tested interventions. Importantly, this genetic information could help identify participants who may have greater absolute benefit from such interventions.

Association between elevated fibrosis-4 index of liver fibrosis and risk of hemorrhagic stroke

BACKGROUND

Cirrhosis is associated with an increased risk of hemorrhagic stroke. Liver fibrosis, typically a silent condition, is antecedent to cirrhosis. The objective of this study was to test the hypothesis that elevated Fibrosis-4 (FIB-4) index, indicating a high probability of liver fibrosis, is associated with an increased risk of hemorrhagic stroke.

METHODS

We performed a cohort analysis of the prospective United Kingdom Biobank cohort study. Participants 40-69 years old were enrolled between 2007 and 2010 and had available follow-up data until March 1, 2018. We excluded participants with prevalent hemorrhagic stroke or thrombocytopenia. High probability of liver fibrosis was defined as having a value >2.67 of the validated FIB-4 index. The primary outcome was hemorrhagic stroke (intracerebral or subarachnoid hemorrhage), defined based on hospitalization and death registry data. Secondary outcomes were intracerebral and subarachnoid hemorrhage, separately. We used Cox proportional hazards models to evaluate the association of FIB-4 index >2.67 with hemorrhagic stroke while adjusting for potential confounders including hypertension, alcohol use, and antithrombotic use.

RESULTS

Among 452,994 participants (mean age, 57 years; 54% women), approximately 2% had FIB-4 index >2.67, and 1241 developed hemorrhagic stroke. In adjusted models, FIB-4 index >2.67 was associated with an increased risk of hemorrhagic stroke (HR, 2.0; 95% CI, 1.6-2.6). Results were similar for intracerebral hemorrhage (HR, 2.0; 95% CI, 1.5-2.7) and subarachnoid hemorrhage (HR, 2.2; 95% CI, 1.5-3.5) individually.

CONCLUSIONS

Elevated FIB-4 index was associated with an increased risk of hemorrhagic stroke.

Risk Factors for Intracerebral Hemorrhage: Genome-Wide Association Study and Mendelian Randomization Analyses

BACKGROUND

The genetic and nongenetic causes of intracerebral hemorrhage (ICH) remain obscure. The present study aimed to uncover the genetic and modifiable risk factors for ICH.

METHODS

We meta-analyzed genome-wide association study data from 3 European biobanks, involving 7605 ICH cases and 711 818 noncases, to identify the genomic loci linked to ICH. To uncover the potential causal associations of cardiometabolic and lifestyle factors with ICH, we performed Mendelian randomization analyses using genetic instruments identified in previous genome-wide association studies of the exposures and ICH data from the present genome-wide association study meta-analysis. We performed multivariable Mendelian randomization analyses to examine the independent associations of the identified risk factors with ICH and evaluate potential mediating pathways.

RESULTS

We identified 1 ICH risk locus, located at the APOE genomic region. The lead variant in this locus was rs429358 (chr19:45411941), which was associated with an odds ratio of ICH of 1.17 (95% CI, 1.11-1.20; P=6.01×10-11) per C allele. Genetically predicted higher levels of body mass index, visceral adiposity, diastolic blood pressure, systolic blood pressure, and lifetime smoking index, as well as genetic liability to type 2 diabetes, were associated with higher odds of ICH after multiple testing corrections. Additionally, a genetic increase in waist-to-hip ratio and liability to smoking initiation were consistently associated with ICH, albeit at the nominal significance level (P<0.05). Multivariable Mendelian randomization analysis showed that the association between body mass index and ICH was attenuated on adjustment for type 2 diabetes and further that type 2 diabetes may be a mediator of the body mass index-ICH relationship.

CONCLUSIONS

Our findings indicate that the APOE locus contributes to ICH genetic susceptibility in European populations. Excess adiposity, elevated blood pressure, type 2 diabetes, and smoking were identified as the chief modifiable cardiometabolic and lifestyle factors for ICH.

Management of cerebral amyloid angiopathy and atrial fibrillation: We are still far from precision medicine

The use of anticoagulation therapy could prove to be controversial when trying to balance ischemic stroke and intracranial bleeding risks in patients with concurrent cerebral amyloid angiopathy (CAA) and atrial fibrillation (AF). In fact, CAA is an age-related cerebral vasculopathy that predisposes patients to intracerebral hemorrhage. Nevertheless, many AF patients require oral systemic dose-adjusted warfarin, direct oral anticoagulants (such as factor Xa inhibitors) or direct thrombin inhibitors to control often associated with cardioembolic stroke risk. The prevalence of both CAA and AF is expected to rise, due to the aging of the population. This clinical dilemma is becoming increasingly common. In patients with coexisting AF and CAA, the risks/benefits profile of anticoagulant therapy must be assessed for each patient individually due to the lack of a clear-cut consensus with regard to its risks in scientific literature. This review aims to provide an overview of the management of patients with concomitant AF and CAA and proposes the implementation of a risk-based decision-making algorithm.

Three major effects of APOEε4 on Aβ immunotherapy induced ARIA

The targeting of amyloid-beta (Aβ) plaques therapeutically as one of the primary causes of Alzheimer's disease (AD) dementia has been an ongoing effort spanning decades. While some antibodies are extremely promising and have been moved out of clinical trials and into the clinic, most of these treatments show similar adverse effects in the form of cerebrovascular damage known as amyloid-related imaging abnormalities (ARIA). The two categories of ARIA are of major concern for patients, families, and prescribing physicians, with ARIA-E presenting as cerebral edema, and ARIA-H as cerebral hemorrhages (micro- and macro-). From preclinical and clinical trials, it has been observed that the greatest genetic risk factor for AD, APOEε4, is also a major risk factor for anti-Aβ immunotherapy-induced ARIA. APOEε4 carriers represent a large population of AD patients, and, therefore, limits the broad adoption of these therapies across the AD population. In this review we detail three hypothesized mechanisms by which APOEε4 influences ARIA risk: (1) reduced cerebrovascular integrity, (2) increased neuroinflammation and immune dysregulation, and (3) elevated levels of CAA. The effects of APOEε4 on ARIA risk is clear, however, the underlying mechanisms require more research.

Lewy body pathology modifies risk factors for cerebral amyloid angiopathy when comorbid with Alzheimer's disease pathology

INTRODUCTION

Cerebral amyloid angiopathy (CAA) often accompanies dementia-associated pathologies and is important in the context of anti-amyloid monoclonal therapies and risk of hemorrhage.

METHODS

We conducted a retrospective neuropathology-confirmed study of 2384 participants in the National Alzheimer Coordinating Center cohort (Alzheimer's disease [AD], n = 1175; Lewy body pathology [LBP], n = 316; and mixed AD and LBP [AD-LBP], n = 893). We used logistic regression to evaluate age, sex, education, APOE ε4, neuritic plaques, and neurofibrillary tangles (NFTs) in CAA risk.

RESULTS

APOE ε4 increased CAA risk in all three groups, while younger age and higher NFT stages increased risk in AD and AD-LBP. In AD-LBP, male sex and lower education were additional risk factors. The odds of APOE ε4 carrier homozygosity related to CAA was higher in LBP (25.69) and AD-LBP (9.50) than AD (3.17).

DISCUSSION

AD and LBPs modify risk factors for CAA and should be considered in reviewing the risk of CAA.

HIGHLIGHTS

Lewy body pathology modifies risk factors for cerebral amyloid angiopathy (CAA) when present along with Alzheimer's disease (AD) neuropathology. In the context of anti-amyloid monoclonal therapies and their associated risks for hemorrhage, the risk of underlying CAA in mixed dementia with Lewy body pathology needs to be considered.

APOE ε4 and Intracerebral Hemorrhage in Patients With Brain Arteriovenous Malformation

Importance

Intracerebral hemorrhage (ICH) is a serious complication of brain arteriovenous malformation (AVM). Apolipoprotein E (APOE) ε4 is a well-known genetic risk factor for ICH among persons without AVM, and cerebral amyloid angiopathy is a vasculopathy frequently observed in APOE ε4 carriers that may increase the risk of ICH.

Objective

To assess whether APOE ε4 is associated with a higher risk of ICH in patients with a known AVM.

Design, Setting, and Participants

This cross-sectional study including 412 participants was conducted in 2 stages (discovery and replication) using individual-level data from the UK Biobank (released March 2012 and last updated October 2023) and the All of Us Research Program (commenced on May 6, 2018, with its latest update provided in October 2023). The occurrence of AVM and ICH was ascertained at the time of enrollment using validated International Classification of Diseases, Ninth Revision and Tenth Revision, codes. Genotypic data on the APOE variants rs429358 and rs7412 were used to ascertain the ε status.

Main Outcomes and Measures

For each study, the association between APOE ε4 variants and ICH risk was assessed among patients with a known AVM by using multivariable logistic regression.

Results

The discovery phase included 253 UK Biobank participants with known AVM (mean [SD] age, 56.6 [8.0] years, 119 [47.0%] female), of whom 63 (24.9%) sustained an ICH. In the multivariable analysis of 240 participants of European ancestry, APOE ε4 was associated with a higher risk of ICH (odds ratio, 4.58; 95% CI, 2.13-10.34; P < .001). The replication phase included 159 participants with known AVM enrolled in All of Us (mean [SD] age, 57.1 [15.9] years; 106 [66.7%] female), of whom 29 (18.2%) sustained an ICH. In multivariable analysis of 101 participants of European ancestry, APOE ε4 was associated with higher risk of ICH (odds ratio, 4.52; 95% CI, 1.18-19.38; P = .03).

Conclusions and Relevance

The results of this cross-sectional study of patients from the UK Biobank and All of Us suggest that information on APOE ε4 status may help identify patients with brain AVM who are at particularly high risk of ICH and that cerebral amyloid angiopathy should be evaluated as a possible mediating mechanism of the observed association.

A Genomic Risk Score Identifies Individuals at High Risk for Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) has an estimated heritability of 29%. We developed a genomic risk score for ICH and determined its predictive power in comparison to standard clinical risk factors.

METHODS

We combined genome-wide association data from individuals of European ancestry for ICH and related traits in a meta-genomic risk score ([metaGRS]; 2.6 million variants). We tested associations with ICH and its predictive performance in addition to clinical risk factors in a held-out validation dataset (842 cases and 796 controls). We tested associations with risk of incident ICH in the population-based UK Biobank cohort (486 784 individuals, 1526 events, median follow-up 11.3 years).

RESULTS

One SD increment in the metaGRS was significantly associated with 31% higher odds for ICH (95% CI, 1.16-1.48) in age-, sex- and clinical risk factor-adjusted models. The metaGRS identified individuals with almost 5-fold higher odds for ICH in the top score percentile (odds ratio, 4.83 [95% CI, 1.56-21.2]). Predictive models for ICH incorporating the metaGRS in addition to clinical predictors showed superior performance compared to the clinical risk factors alone (c-index, 0.695 versus 0.686). The metaGRS showed similar associations for lobar and nonlobar ICH, independent of the known APOE risk locus for lobar ICH. In the UK Biobank, the metaGRS was associated with higher risk of incident ICH (hazard ratio, 1.15 [95% CI, 1.09-1.21]). The associations were significant within both a relatively high-risk population of antithrombotic medications users, as well as among a relatively low-risk population with a good control of vascular risk factors and no use of anticoagulants.

CONCLUSIONS

We developed and validated a genomic risk score that predicts lifetime risk of ICH beyond established clinical risk factors among individuals of European ancestry. Whether implementation of the score in risk prognostication models for high-risk populations, such as patients under antithrombotic treatment, could improve clinical decision making should be explored in future studies.

Genetic considerations in cerebral small vessel diseases

Cerebral small vessel disease (CSVD) encompasses a broad clinical spectrum united by pathology of the small vessels of the brain. CSVD is commonly identified using brain magnetic resonance imaging with well characterized markers including covert infarcts, white matter hyperintensities, enlarged perivascular spaces, and cerebral microbleeds. The pathophysiology of CSVD is complex involving genetic determinants, environmental factors, and their interactions. While the role of vascular risk factors in CSVD is well known and its management is pivotal in mitigating the clinical effects, recent research has identified novel genetic factors involved in CSVD. Delineating genetic determinants can promote the understanding of the disease and suggest effective treatments and preventive measures of CSVD at the individual level. Here we review CSVD focusing on recent advances in the genetics of CSVD. The knowledge gained has advanced understanding of the pathophysiology of CSVD, offered promising early results that may improve subtype identification of small vessel strokes, has led to additional identification of mendelian forms of small vessel strokes, and is getting closer to influencing clinical care through pharmacogenetic studies.

Cerebral Superficial Siderosis

Superficial siderosis (SS) of the central nervous system constitutes linear hemosiderin deposits in the leptomeninges and the superficial layers of the cerebrum and the spinal cord. Infratentorial (i) SS is likely due to recurrent or continuous slight bleeding into the subarachnoid space. It is assumed that spinal dural pathologies often resulting in cerebrospinal fluid (CSF) leakage is the most important etiological group which causes iSS and detailed neuroradiological assessment of the spinal compartment is necessary. Further etiologies are neurosurgical interventions, trauma and arteriovenous malformations. Typical neurological manifestations of this classical type of iSS are slowly progressive sensorineural hearing impairment and cerebellar symptoms, such as ataxia, kinetic tremor, nystagmus and dysarthria. Beside iSS, a different type of SS restricted to the supratentorial compartment can be differentiated, i.e. cortical (c) SS, especially in older people often due to cerebral amyloid angiopathy (CAA). Clinical presentation of cSS includes transient focal neurological episodes or “amyloid spells”. In addition, spontaneous and amyloid beta immunotherapy-associated CAA-related inflammation may cause cSS, which is included in the hemorrhagic subgroup of amyloid-related imaging abnormalities (ARIA). Because a definitive diagnosis requires a brain biopsy, knowledge of neuroimaging features and clinical findings in CAA-related inflammation is essential. This review provides neuroradiological hallmarks of the two groups of SS and give an overview of neurological symptoms and differential diagnostic considerations.

Forkhead box O3 longevity genotype may attenuate the impact of hypertension on risk of intracerebral haemorrhage

OBJECTIVE

Since the G allele of forkhead box O3 ( FOXO3 ) single nucleotide polymorphism (SNP) rs2802292 is associated with resilience and longevity, ostensibly by mitigating the adverse effects of chronic cardiometabolic stress on mortality, our aim was to determine the association between the FOXO3 SNP rs2802292 genotype and risk of hypertension-mediated intracerebral haemorrhage (ICH).

METHODS

From a prospective population-based cohort of Japanese American men from the Kuakini Honolulu Heart Program (KHHP), age-adjusted prevalence of ICH by hypertension was assessed for the whole cohort after stratifying by FOXO3 genotype. Cox regression models, adjusted for age, cardiovascular risk factors and, FOXO3 and APOE genotypes, were utilized to determine relative risk of hypertension's effect on ICH. All models were created for the whole cohort and stratified by FOXO3 G -allele carriage vs. TT genotype.

RESULTS

Among 6469 men free of baseline stroke, FOXO3 G -allele carriage was seen in 3009 (46.5%) participants. Overall, 183 participants developed ICH over the 34-year follow-up period. Age-adjusted ICH incidence was 0.90 vs. 1.32 per 1000 person-years follow-up in those without and with hypertension, respectively ( P  = 0.002). After stratifying by FOXO3 genotype, this association was no longer significant in G allele carriers. In the whole cohort, hypertension was an independent predictor of ICH (relative risk [RR] = 1.70, 95% confidence interval [CI] 1.25, 2.32; P  = 0.0007). In stratified analyses, hypertension remained an independent predictor of ICH among the FOXO3 TT -genotype group (RR = 2.02, 95% CI 1.33, 3.07; P  = 0.001), but not in FOXO3 G -allele carriers (RR = 1.39, 95% CI 0.88, 2.19; P  = 0.15).

CONCLUSIONS

The longevity-associated FOXO3   G allele may attenuate the impact of hypertension on ICH risk.

Epidemiology of intracerebral hemorrhage: A systematic review and meta-analysis

Background

Intracerebral hemorrhage (ICH) is associated with high mortality and disability rates. This study aimed to investigate the relationship between sex, age, study year, risk factors, bleeding site, median year of study, and the incidence of ICH.

Method

Literature on the incidence of ICH published on 1 January 1980 and 1 January 2020, was systematically retrieved from PubMed and Embase databases. The random-effects model and subgroup analysis were used to explore the relationship between the incidence of ICH and different ages, sex, bleeding sites, and risk factors.

Results

We summarized the epidemiological changes in ICH in the past 40 years according to 52 studies and found that the total incidence of ICH is 29.9 per 100,000 person-years (95% CI: 26.5–33.3), which has not decreased worldwide. The incidence of ICH in the Asian population is much higher than in other continents. In addition, the incidence of ICH increases with age and differs at the 85-year-old boundary. Men are more likely to develop ICH than women, and the basal ganglia region is the most common area for ICH. Of the 10 risk factors examined in this study, those with hypertension had the highest incidence of ICH, followed by those with excessive alcohol consumption and heart disease.

Conclusion

The prevention and treatment of ICH still need to be improved continuously according to age, sex, risk factors, and other factors, and targeted and normative strategies should be gradually developed in the future.

Genetics and Epigenetics of Spontaneous Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a complex and heterogeneous disease, and there is no effective treatment. Spontaneous ICH represents the final manifestation of different types of cerebral small vessel disease, usually categorized as: lobar (mostly related to cerebral amyloid angiopathy) and nonlobar (hypertension-related vasculopathy) ICH. Accurate phenotyping aims to reflect these biological differences in the underlying mechanisms and has been demonstrated to be crucial to the success of genetic studies in this field. This review summarizes how current knowledge on genetics and epigenetics of this devastating stroke subtype are contributing to improve the understanding of ICH pathophysiology and their potential role in developing therapeutic strategies.

In Search of the Optimal Antithrombotic Regimen for Intracerebral Hemorrhage Survivors with Atrial Fibrillation

Spontaneous intracerebral hemorrhage (ICH) constitutes 10-15% of all strokes, and is a significant cause of mortality and morbidity. Survivors of ICH, especially those with atrial fibrillation (AF), are at risk for both recurrent hemorrhagic and ischemic cerebrovascular events. A conundrum in the field of vascular neurology, neurosurgery, and cardiology has been the decision to initiate or resume versus withhold anticoagulation in survivors of ICH with AF. To initiate anticoagulation would decrease the risk of ischemic stroke but may increase the risk of hemorrhage. To withhold anticoagulation maintains a lower risk of hemorrhage but does not decrease the risk of ischemic stroke. In this narrative review, we discuss the evidence for and against the use of antithrombotics in ICH survivors with AF, focusing on recently completed and ongoing clinical trials.

Genetics of Spontaneous Intracerebral Hemorrhage: Risk and Outcome

Spontaneous intracerebral hemorrhage (ICH) is a common fatal event without an effective therapy. Of note, some familial aggregation and inherited tendency is found in ICH and heritability estimates indicate that genetic variations contribute substantially to ICH risk and outcome. Thus, identification of genetic variants that affect the occurrence and outcome may be helpful for ICH prevention and therapy. There are several reviews summarizing numerous genetic variants associated with the occurrence of ICH before, but genetic variants contributing to location distribution and outcome have rarely been introduced. Here, we summarize the current knowledge of genetic variants and pay special attention to location distribution and outcome. So far, investigations have reveled variations in APOE, GPX1, CR1, ITGAV, PRKCH, and 12q21.1 are associated with lobar ICH (LICH), while ACE, COL4A2, 1q22, TIMP1, TIMP2, MMP2, MMP9, and TNF are associated with deep ICH (DICH). Moreover, variations in APOE, VWF, 17p12, HP, CFH, IL6ST, and COL4A1 are possible genetic contributors to ICH outcome. Furthermore, the prospects for ICH related genetic studies from the bench to the bed were discussed.

CT-Visible Convexity Subarachnoid Hemorrhage Predicts Early Recurrence of Lobar Hemorrhage

Background and Purpose

Convexity subarachnoid hemorrhage (cSAH) may predict an increased recurrence risk in cerebral amyloid angiopathy (CAA)-related intracerebral hemorrhage (ICH) survivors. We aimed to investigate whether cSAH detected on CT was related to early recurrence in patients with ICH related to CAA.

Methods

We analyzed data from consecutive lobar ICH patients diagnosed as probable or possible CAA according to the Boston criteria using the method of cohort study. Demographic and clinical data, ICH recurrence at discharge and within 90 days were collected. The association between cSAH detected on CT and early recurrent ICH was analyzed using multivariable logistic regression.

Results

A total of 197 cases (74 [66–80] years) were included. cSAH was observed on the baseline CT of 91 patients (46.2%). A total of 5.1% (10/197) and 9.5% (17/179) of patients experienced ICH recurrence within 2 weeks and 90 days, respectively. The presence of cSAH was related to recurrence within 2 weeks (OR = 5.705, 95%CI 1.070–30.412, P = 0.041) after adjusting for hypertension, previous symptomatic ICH and anticoagulant use. The presence of cSAH was related to recurrence within 90 days (OR 5.473, 95%CI 1.425–21.028, P = 0.013) after adjusting for hypertension, previous symptomatic ICH and intraventricular hemorrhage. The similar results were obtained in other models using different methods to select adjusting variables.

Conclusion

In patients with lobar ICH related to CAA, 5.1% and 9.5% of them experienced ICH recurrence within 2 weeks and 90 days, respectively. CT-visible cSAH was detected in 46.2% of patients and indicates an increased risk for early recurrent ICH.

Human Galectin-7 Gene LGALS7 Promoter Sequence Polymorphisms and Risk of Spontaneous Intracerebral Hemorrhage: A Prospective Study

Background and purpose

Despite evidence for the role of genetic factors in stroke, only a small proportion of strokes have been clearly attributed to monogenic factors, due to phenotypic heterogeneity. The goal of this study was to determine whether a significant relationship exists between human galectin-7 gene LGALS7 promoter region polymorphisms and the risk of stroke due to non-traumatic intracerebral hemorrhage (ICH).

Methods

This two-stage genetic association study included an initial exploratory stage followed by a discovery stage. During the exploratory stage, transgenic galectin-7 mice or transgenic mice with the scrambled sequence of the hairpin structure –silenced down gene LGALS7—were generated and then expressed differentially expressed proteins and galectin-7-interacting proteins were identified through proteomic analysis. During the discovery stage, a single-nucleotide polymorphism (SNP) genotyping approach was used to determine associations between 2 LGALS7 SNPs and ICH stroke risk for a cohort of 24 patients with stroke of the Chinese Han population and 70 controls.

Results

During the exploratory phase, LGALS7 expression was found to be decreased in TGLGALS–DOWN mice as compared to its expression in TGLGALS mice. During the discovery phase, analysis of LGALS7 sequences of 24 non-traumatic ICH cases and 70 controls led to the identification of 2 ICH susceptibility loci: a genomic region on 19q13.2 containing two LGALS7 SNPs, rs567785577 and rs138945880, whereby the A allele of rs567785577 and the T allele of rs138945880 were associated with greater risk of contracting ICH [for T and A vs. C and G, unadjusted odds ratio (OR) = 13.5; 95% CI = 2.249–146.5; p = 0.002]. This is the first study to genotype the galectin-7 promoter in patients with hemorrhagic stroke. Genotype and allele association tests and preliminary analysis of patients with stroke revealed that a single locus may be a genetic risk factor for hemorrhagic stroke.

Conclusion

A and T alleles of two novel SNP loci of 19q13.2, rs567785577 and rs138945880, respectively, were evaluated for associations with susceptibility to ICH. Further studies with expanded case numbers that include subjects of other ethnic populations are needed to elucidate mechanisms underlying associations between these SNPs and ICH risk.

Biological and Social Determinants of Hypertension Severity Before vs After Intracerebral Hemorrhage

BACKGROUND AND OBJECTIVES

Although blood pressure (BP) control is considered the most effective measure to prevent functional decline after intracerebral hemorrhage (ICH), less than half of survivors achieve treatment goals. We hypothesized that long-term (i.e., pre-hemorrhage) hypertension severity may be a crucial factor in explaining poor BP control after ICH. We investigated changes in hypertension severity after vs before ICH using Latent Class Analysis (LCA), and identified patient characteristics predictive of individuals' BP trajectories.

METHODS

We analyzed data for ICH survivors enrolled in a study conducted at Massachusetts General Hospital (MGH) from 2002 to 2019 in Boston MA, a high-resource setting with near-universal medical insurance coverage. We captured BP measurements in the 12 months preceding and following the acute ICH hospitalization. Using LCA we identified patient groups (classes) based on changes in hypertension severity over time in an unbiased manner. We then created multinomial logistic regression models to identify patient factors associated with these classes.

RESULTS

Among 336 participants the average age was 74.4 years, 166 (49%) were male, and 288 (86%) self-reported White race/ethnicity. LCA identified 3 patient classes, corresponding to minimal (n = 114, 34%), intermediate (n = 128, 38%) and substantial (n = 94, 28%) improvement in hypertension severity after vs before ICH. Survivors with undertreated (Relative Risk Ratio [RRR] 0.05, 95% Confidence Interval [CI] 0.01-0.23) or resistant (RRR 0.03, 95% CI 0.01-0.06) hypertension before ICH were less likely to experience substantial improvement afterwards. Residents of high-income neighborhoods were more likely to experience substantial improvement (RRR 1.14 per $10,000, 95% CI 1.02-1.28). Black, Hispanic and Asian participants with uncontrolled hypertension before ICH were more likely to experience minimal improvement after hemorrhagic stroke (interaction p < 0.001).

DISCUSSION

Most ICH survivors do not display consistent improvement in hypertension severity after hemorrhagic stroke compared to prior. BP control after ICH is profoundly influenced by patient characteristics predating the hemorrhage, chiefly pre-stroke hypertension severity and socio-economic status. Of note, neighborhood income was associated with hypertension severity after ICH in a high-resource setting with near-universal healthcare coverage. Furthermore, these findings likely contribute to previously documented racial/ethnic disparities in BP control and clinical outcomes following ICH.

Association between Apolipoprotein E Polymorphism and Clinical Outcome after Ischemic Stroke, Intracerebral Hemorrhage, and Subarachnoid Hemorrhage

BACKGROUNDS

Previous studies reported inconsistent results regarding associations between apolipoprotein E (APOE) polymorphism and clinical outcomes after ischemic stroke (IS), intracerebral hemorrhage (ICH), or subarachnoid hemorrhage (SAH). Thus, the study was designed to make a systematic review and meta-analysis regarding the association between APOE polymorphism and clinical outcome after IS, ICH, and SAH.

METHODS

To identify studies eligible for this meta-analysis, we searched for articles published before August 2021 in the databases (PubMed, Web of Science, and Google Scholar). We used STATA 12.0 software to compute hazard ratios (HRs) and their 95% confidence intervals (CIs) regarding APOE polymorphism and clinical outcome after IS, ICH, and SAH.

RESULTS

Meta-analysis showed no significant association between APOE polymorphism and functional outcome after IS with fixed effects models (ε4 carrier vs. non-ε4 carrier: HR, 1.00; 95% CI: 0.83-1.21, I2 = 29.4%, p = 0.183; ε2 carrier vs. non-ε2 carrier: HR, 0.92; 95% CI: 0.72-1.16, I2 = 15.6%, p = 0.307). Meta-analysis showed that ICH patients carrying ε4 allele have increased risk of poor outcome in Caucasian population with fixed effects models (ε4 carrier vs. non-ε4 carrier: HR, 1.75; 95% CI: 1.19-2.57, I2 = 0.0%, p = 0.543). Meta-analysis showed no significant association between APOE polymorphism and functional outcomes after SAH with random effects models (ε4 carrier vs. non-ε4 carrier: HR, 1.51; 95% CI: 0.80-2.84, I2 = 57.1%, p = 0.022).

CONCLUSIONS

In conclusion, the present study demonstrated APOE ε4 carriers show worse functional outcomes after ICH, but not after IS or SAH. More large-scale studies were critical to explore the association between APOE polymorphism and clinical outcome after IS, ICH, and SAH.

Genetic and Genomic Epidemiology of Stroke in People of African Ancestry

Stroke is one of the leading causes of disability and death worldwide and places a significant burden on healthcare systems. There are significant racial/ethnic differences in the incidence, subtype, and prognosis of stroke, between people of European and African ancestry, of which only about 50% can be explained by traditional stroke risk facts. However, only a small number of genetic studies include individuals of African descent, leaving many gaps in our understanding of stroke genetics among this population. This review article highlights the need for and significance of including African-ancestry individuals in stroke genetic studies and points to the efforts that have been made towards this direction. Additionally, we discuss the caveats, opportunities, and next steps in African stroke genetics-a field still in its infancy but with great potential for expanding our understanding of stroke biology and for developing new therapeutic strategies.

Stroke Prevention After Intracerebral Hemorrhage: Where Are We Now?

PURPOSE OF REVIEW

Patients after intracerebral hemorrhage (ICH) are at high risk of both ischemic stroke and recurrent ICH, and stroke prevention after ICH is important to improve the long-term outcomes in this patient population. The objective of this article is to review the current guidelines on stroke prevention measures after ICH as well as the new findings and controversies for future guidance.

RECENT FINDINGS

Intensive blood pressure reduction might benefit ICH survivors significantly. Cholesterol levels and the risk of ICH have an inverse relationship, but statin therapy after ICH might be still beneficial. Anticoagulation in atrial fibrillation after ICH specifically with novel oral anticoagulants may be associated with better long-term outcomes. Left atrial appendage occlusion may be an alternative for stroke prevention in ICH survivors with atrial fibrillation for whom long-term anticoagulation therapy is contraindicated. While complete individualized risk assessment is imperative to prevent stroke after ICH, future research is required to address current controversies and knowledge gap in this topic.

Moderators of gene-outcome associations following traumatic brain injury

The field of genomics is the principal avenue in the ongoing development of precision/personalised medicine for a variety of health conditions. However, relating genes to outcomes is notoriously complex, especially when considering that other variables can change, or moderate, gene-outcome associations. Here, we comprehensively discuss moderation of gene-outcome associations in the context of traumatic brain injury (TBI), a common, chronically debilitating, and costly neurological condition that is under complex polygenic influence. We focus our narrative review on single nucleotide polymorphisms (SNPs) of three of the most studied genes (apolipoprotein E, brain-derived neurotrophic factor, and catechol-O-methyltransferase) and on three demographic variables believed to moderate associations between these SNPs and TBI outcomes (age, biological sex, and ethnicity). We speculate on the mechanisms which may underlie these moderating effects, drawing widely from biomolecular and behavioural research (n = 175 scientific reports) within the TBI population (n = 72) and other neurological, healthy, ageing, and psychiatric populations (n = 103). We conclude with methodological recommendations for improved exploration of moderators in future genetics research in TBI and other populations.

Ethnic and Racial Variation in Intracerebral Hemorrhage Risk Factors and Risk Factor Burden

Importance

Black and Hispanic individuals have an increased risk of intracerebral hemorrhage (ICH) compared with their White counterparts, but no large studies of ICH have been conducted in these disproportionately affected populations.

Objective

To examine the prevalence, odds, and population attributable risk (PAR) percentage for established and novel risk factors for ICH, stratified by ICH location and racial/ethnic group.

Design, Setting, and Participants

The Ethnic/Racial Variations of Intracerebral Hemorrhage Study was a case-control study of ICH among 3000 Black, Hispanic, and White individuals who experienced spontaneous ICH (1000 cases in each group). Recruitment was conducted between September 2009 and July 2016 at 19 US sites comprising 42 hospitals. Control participants were identified through random digit dialing and were matched to case participants by age (±5 years), sex, race/ethnicity, and geographic area. Data analyses were conducted from January 2019 to May 2020.

Main Outcomes and Measures

Case and control participants underwent a standardized interview, physical measurement for body mass index, and genotyping for the ɛ2 and ɛ4 alleles of APOE, the gene encoding apolipoprotein E. Prevalence, multivariable adjusted odds ratio (OR), and PAR percentage were calculated for each risk factor in the entire ICH population and stratified by racial/ethnic group and by lobar or nonlobar location.

Results

There were 1000 Black patients (median [interquartile range (IQR)] age, 57 [50-65] years, 425 [42.5%] women), 1000 Hispanic patients (median [IQR] age, 58 [49-69] years; 373 [37.3%] women), and 1000 White patients (median [IQR] age, 71 [59-80] years; 437 [43.7%] women). The mean (SD) age of patients with ICH was significantly lower among Black and Hispanic patients compared with White patients (eg, lobar ICH: Black, 62.2 [15.2] years; Hispanic, 62.5 [15.7] years; White, 71.0 [13.3] years). More than half of all ICH in Black and Hispanic patients was associated with treated or untreated hypertension (PAR for treated hypertension, Black patients: 53.6%; 95% CI, 46.4%-59.8%; Hispanic patients: 46.5%; 95% CI, 40.6%-51.8%; untreated hypertension, Black patients: 45.5%; 95% CI, 39.%-51.1%; Hispanic patients: 42.7%; 95% CI, 37.6%-47.3%). Lack of health insurance also had a disproportionate association with the PAR percentage for ICH in Black and Hispanic patients (Black patients: 21.7%; 95% CI, 17.5%-25.7%; Hispanic patients: 30.2%; 95% CI, 26.1%-34.1%; White patients: 5.8%; 95% CI, 3.3%-8.2%). A high sleep apnea risk score was associated with both lobar (OR, 1.68; 95% CI, 1.36-2.06) and nonlobar (OR, 1.62; 95% CI, 1.37-1.91) ICH, and high cholesterol was inversely associated only with nonlobar ICH (OR, 0.60; 95% CI, 0.52-0.70); both had no interactions with race and ethnicity. In contrast to the association between the ɛ2 and ɛ4 alleles of APOE and ICH in White individuals (eg, presence of APOE ɛ2 allele: OR, 1.84; 95% CI, 1.34-2.52), APOE alleles were not associated with lobar ICH among Black or Hispanic individuals.

Conclusions and Relevance

This study found sleep apnea as a novel risk factor for ICH. The results suggest a strong contribution from inadequately treated hypertension and lack of health insurance to the disproportionate burden and earlier onset of ICH in Black and Hispanic populations. These findings emphasize the importance of addressing modifiable risk factors and the social determinants of health to reduce health disparities.

Race-Related Association between APOE Genotype and Alzheimer's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

The global race-dependent association of Alzheimer's disease (AD) and apolipoprotein E (APOE) genotype is not well understood. Transethnic analysis of APOE could clarify the role of genetics in AD risk across populations.

OBJECTIVE

This study aims to determine how race and APOE genotype affect the risks for AD.

METHODS

We performed a systematic search of PubMed, Embase, Web of Science, and the Cochrane Library since 1993 to Aug 25, 2020. A total of 10,395 reports were identified, and 133 were eligible for analysis with data on 77,402 participants. Studies contained AD clinical diagnostic and APOE genotype data. Homogeneous data sets were pooled in case-control analyses. Odds ratios and 95% confidence intervals for developing AD were calculated for populations of different races and APOE genotypes.

RESULTS

The proportion of APOE genotypes and alleles differed between populations of different races. Results showed that APOEɛ4 was a risk factor for AD, whereas APOEɛ2 protected against it. The effects of APOEɛ4 and ɛ2 on AD risk were distinct in various races, they were substantially attenuated among Black people. Sub-group analysis found a higher frequency of APOEɛ4/ɛ4 and lower frequency of APOEɛ3/ɛ3 among early-onset AD than late-onset AD in a combined group and different races.

CONCLUSION

Our meta-analysis suggests that the association of APOE genotypes and AD differ between races. These results enhance our understanding of APOE-related risk for AD across race backgrounds and provide new insights into precision medicine for AD.

Cerebral microbleeds in vascular dementia from clinical aspects to host-microbial interaction

Vascular dementia is the second leading cause of dementia after Alzheimer's disease in the elderly population worldwide. Cerebral microbleeds (CMBs) are frequently observed in MRI of elderly subjects and considered as a possible surrogate marker. The number and location of CMBs reflect the severity of diseases and the underlying pathologies may involve cerebral amyloid angiopathy or hypertensive vasculopathy. Accumulating evidence demonstrated the clinicopathological discrepancies of CMBs, the clinical significance of CMBs associated with other MRI markers of cerebral small vessel disease, cognitive impairments, serum, and cerebrospinal fluid biomarkers. Moreover, emerging evidence has shown that genetic factors and gene-environmental interactions might shed light on the underlying etiologies of CMBs, focusing on blood-brain-barrier and inflammation. In this review, we introduce recent genetic and microbiome studies as a cutting-edge approach to figure out the etiology of CMBs through the "microbe-brain-oral axis" and "microbiome-brain-gut axis." Finally, we propose novel concepts, "microvascular matrisome" and "imbalanced proteostasis," which may provide better perspectives for elucidating the pathophysiology of CMBs and future development of therapeutics for vascular dementia using CMBs as a surrogate marker.

Contribution of Racial and Ethnic Differences in Cerebral Small Vessel Disease Subtype and Burden to Risk of Cerebral Hemorrhage Recurrence

OBJECTIVE

Black and Hispanic survivors of intracerebral hemorrhage (ICH) are at higher risk of recurrent intracranial bleeding. MRI-based markers of chronic cerebral small vessel disease (CSVD) are consistently associated with recurrent ICH. We therefore sought to investigate whether racial/ethnic differences in MRI-defined CSVD subtype and severity contribute to disparities in ICH recurrence risk.

METHODS

We analyzed data from the Massachusetts General Hospital ICH study (n = 593) and the Ethnic/Racial Variations of Intracerebral Hemorrhage (ERICH) study (n = 329). Using CSVD markers derived from MRIs obtained within 90 days of index ICH, we classified ICH cases as cerebral amyloid angiopathy (CAA)-related, hypertensive arteriopathy (HTNA)-related, and mixed etiology. We quantified CSVD burden using validated global, CAA-specific, and HTNA-specific scores. We compared CSVD subtype and severity among White, Black, and Hispanic ICH survivors and investigated its association with ICH recurrence risk.

RESULTS

We analyzed data for 922 ICH survivors (655 White, 130 Black, 137 Hispanic). Minority ICH survivors had greater global CSVD (p = 0.011) and HTNA burden (p = 0.021) on MRI. Furthermore, minority survivors of HTNA-related and mixed-etiology ICH demonstrated higher HTNA burden, resulting in increased ICH recurrence risk (all p < 0.05).

CONCLUSIONS

We uncovered significant differences in CSVD subtypes and severity among White and minority survivors of primary ICH, with direct implication for known disparities in ICH recurrence risk. Future studies of racial/ethnic disparities in ICH outcomes will benefit from including detailed MRI-based assessment of CSVD subtypes and severity and investigating social determinants of health.

Current Management and Therapeutic Strategies for Cerebral Amyloid Angiopathy

Cerebral amyloid angiopathy (CAA) is characterized by accumulation of amyloid β (Aβ) in walls of leptomeningeal vessels and cortical capillaries in the brain. The loss of integrity of these vessels caused by cerebrovascular Aβ deposits results in fragile vessels and lobar intracerebral hemorrhages. CAA also manifests with progressive cognitive impairment or transient focal neurological symptoms. Although development of therapeutics for CAA is urgently needed, the pathogenesis of CAA remains to be fully elucidated. In this review, we summarize the epidemiology, pathology, clinical and radiological features, and perspectives for future research directions in CAA therapeutics. Recent advances in mass spectrometric methodology combined with vascular isolation techniques have aided understanding of the cerebrovascular proteome. In this paper, we describe several potential key CAA-associated molecules that have been identified by proteomic analyses (apolipoprotein E, clusterin, SRPX1 (sushi repeat-containing protein X-linked 1), TIMP3 (tissue inhibitor of metalloproteinases 3), and HTRA1 (HtrA serine peptidase 1)), and their pivotal roles in Aβ cytotoxicity, Aβ fibril formation, and vessel wall remodeling. Understanding the interactions between cerebrovascular Aβ deposits and molecules that accumulate with Aβ may lead to discovery of effective CAA therapeutics and to the identification of biomarkers for early diagnosis.

Apolipoprotein E genotype does not influence the risk of symptomatic hemorrhage in acute ischemic stroke

BACKGROUND

APOE ε4 is independently associated with lobar intracranial hemorrhages (ICH). Although the ε4 allele enhances amyloid deposition in blood vessels, the ε2 allele predisposes to vasculopathic changes leading to rupture of amyloid laden vessels. Thus, ε4 and ε2 carriers might have increased susceptibility to ICH. We aimed to study the impact of the apolipoprotein E alleles in the development of symptomatic ICH (sICH).

METHODS

We included 384 consecutive ischemic anterior circulation stroke patients submitted to thrombolysis between January 2014 and March 2016. Admission CT-scans were reviewed to calculate the ASPECTS. Patients were followed for up to at least 6 months post-stroke or until death. Outcome was development of sICH, defined according to the ECASS III.

RESULTS

Considering APOE genotyping, three patients had ε2/ε2, four had ε2/ε4, 38 had ε2/ε3, 284 had ε3/ε3, 51 had ε3/ε4 and four had ε4/ε4. sICH was associated with sex and diabetes. In multivariate analysis, sICH was not associated with carrying one or more ε4 alleles (OR: 0.483, 95%CI = [0.059, 3.939], p = 0.497) nor with carrying one or more ε2 alleles (OR: 1.369, 95%CI = [0.278, 6.734], p = 0.699).

CONCLUSION

No association was found between APOE genotype and the development of symptomatic intracranial hemorrhage.

Intracerebral Hemorrhage with Intraventricular Extension Associated with Loss of Consciousness at Symptom Onset

BACKGROUND

In patients with spontaneous intracerebral hemorrhage (ICH), pre-hospital markers of disease severity might be useful to potentially triage patients to undergo early interventions.

OBJECTIVE

Here, we tested whether loss of consciousness (LOC) at the onset of ICH is associated with intraventricular hemorrhage (IVH) on brain computed tomography (CT).

METHODS

Among 3000 ICH cases from ERICH (Ethnic/Racial Variations of Intracerebral Hemorrhage study, NS069763), we included patients with complete ICH/IVH volumetric CT measurements and excluded those with seizures at ICH onset. Trained investigators extracted data from medical charts. Mental status at symptom onset (categorized as alert/oriented, alert/confused, drowsy/somnolent, coma/unresponsive/posturing) and 3-month disability (modified Rankin score, mRS) were assessed through standardized interviews of participants or dedicated proxies. We used logistic regression and mediation analysis to assess relationships between LOC, IVH, and unfavorable outcome (mRS 4-6).

RESULTS

Two thousand seven hundred and twenty-four patients met inclusion criteria. Median admission Glasgow Coma Score was 15 (interquartile range 11-15). 46% had IVH on admission or follow-up CT. Patients with LOC (mental status: coma/unresponsive, n = 352) compared to those without LOC (all other mental status, n = 2372) were younger (60 vs. 62 years, p = 0.005) and had greater IVH frequency (77 vs. 41%, p < 0.001), greater peak ICH volumes (28 vs. 11 ml, p < 0.001), greater admission systolic blood pressure (200 vs. 184 mmHg, p < 0.001), and greater admission serum glucose (158 vs. 127 mg/dl, p < 0.001). LOC was independently associated with IVH presence (odds ratio, OR, 2.6, CI 1.9-3.5) and with unfavorable outcome (OR 3.05, CI 1.96-4.75). The association between LOC and outcome was significantly mediated by IVH (beta = 0.24, bootstrapped CI 0.17-0.32).

CONCLUSION

LOC at ICH onset may be a useful pre-hospital marker to identify patients at risk of having or developing IVH.

Insights in the pathophysiology of haemorrhagic strokes in a sub-Sahara African country, an epidemiological and MRI study

OBJECTIVE

Intra-cerebral Haemorrhage (ICH) seems more prevalent in sub-Saharan Africa (SSA) than in High-Income Countries (HIC) with poorer clinical outcome. Higher impact of hypertension and/or amyloid angiopathy could account for this disproportion. Here, we sought to (i) retrospectively compare ICH clinical and imaging patterns in Belgium and Guinea and in a subsequent cohort (ii) prospectively compare brain MRI characteristics to seek evidence for a different proportion of amyloid angiopathy patterns.

METHODS

Ninety one consecutive patients admitted for spontaneous ICH at Brussels Erasme-ULB Hospital and at Conakry Ignace Deen-UGANC were retrospectively compared in terms of ICH volume estimated with the ABC/2 method, clinical characteristics and modified ranking (mRS) score at 30 days. mRS was dichotomised as good outcomes (≤3) and poor outcomes (>3). A prospective cohort of 30 consecutive patients with ICH admitted at CHU Conakry Ignace Deen-UGANC was prospectively included to undergo brain MRI. Results of the Guinean MRI were compared to 30 patients randomly selected from Brussels' initial cohort. Paired Student's t-test and Mann-Whitney u-test were used for group comparisons.

RESULTS

Age of ICH onset was higher in Belgium (68 ± 17 years vs. 56 ± 14 years, P < 0.01) while ICH volume and 30-day mortality rate were higher in Guinea (20 ml vs. 11 ml, P < 0.01 and mortality 33% vs. 10 %, P < 0.01). ICH burden in survivors in Conakry and Brussels showed respectively good outcomes in 56.7% and 60.4% (P = 0.09) and poor outcomes in 10.3% vs. 29.6% (P < 0.001). MRI analysis of the prospective cohort failed to disclose significant differences regarding brain MRI characteristics.

CONCLUSIONS

Intra-cerebral Haemorrhage affected patients 15 years younger in Guinea with larger haematoma volumes and higher mortality than in Belgium. MRI findings did not show more prevalent amyloid angiopathy pathology suggesting that better primary prevention of hypertension could positively impact ICH epidemiology in Guinea.

Association of Selective Serotonin Reuptake Inhibitor Use After Intracerebral Hemorrhage With Hemorrhage Recurrence and Depression Severity

IMPORTANCE

Selective serotonin reuptake inhibitors (SSRIs) are widely used to treat poststroke depression but are associated with increased incidence of first-ever intracerebral hemorrhage (ICH) in the general population. The decision to treat ICH survivors with SSRIs must therefore balance potential risks of ICH recurrence with presumed benefits on depressive symptoms.

OBJECTIVE

To determine whether SSRI use among survivors of primary ICH was associated with ICH recurrence and decreased severity of depressive symptoms.

DESIGN, SETTING, AND PARTICIPANTS

Longitudinal ICH cohort study at a tertiary care center enrolling from January 2006 to December 2017, with follow-up for a median of 53.2 months (interquartile range, 42.3-61.2 months). The study included 1279 consenting individuals (1049 White, 89 Black, 77 Hispanic, and 64 other race/ethnicity) of 1335 eligible patients presenting with primary ICH and who were discharged alive from initial hospitalization for stroke.

MAIN OUTCOMES AND MEASURES

We conducted univariable and multivariable analyses for ICH recurrence risk and depression severity, including subset analyses for patients with 1 or more of the following characteristics associated with high ICH recurrence risk: (1) lobar ICH; (2) presence of the apolipoprotein ε2/ε4 gene variants; (3) prior history of ICH/TIA/ischemic stroke; and (4) Black or Hispanic race/ethnicity.

RESULTS

Mean age of study participants was 71.3 years, with 602 women (47%); of the 1279 participants, 1049 were White, 89 were Black, 77 were Hispanic, and 64 were other race/ethnicity. SSRI exposure was associated with both ICH recurrence (subhazard ratio [SHR], 1.31; 95% CI, 1.08-1.59) and resolution of post-ICH depression (SHR, 1.53; 95% CI, 1.12 2.09). Among those individuals at high risk for recurrent ICH, SSRIs were associated with further elevation in risk for ICH recurrence (SHR, 1.79; 95% CI, 1.22-2.64) compared with all other survivors of ICH (SHR, 1.20; 95% CI, 1.01-1.42; P = .008 for comparison of effect sizes). The association of SSRI with reduced depressive symptoms did not differ between high those at high risk for recurrent ICH and all other ICH survivors.

CONCLUSIONS AND RELEVANCE

Selective serotonin reuptake inhibitor exposure after ICH is associated with both improvement in depressive symptoms and increased risk of recurrent hemorrhagic stroke. Clinical history, neuroimaging data, and genetic biomarkers may help to identify survivors of ICH more likely to safely tolerate SSRI use.

Molecular and cellular mechanisms underlying the pathogenesis of Alzheimer's disease

Alzheimer’s disease (AD) is the most common neurodegenerative disorder seen in age-dependent dementia. There is currently no effective treatment for AD, which may be attributed in part to lack of a clear underlying mechanism. Studies within the last few decades provide growing evidence for a central role of amyloid β (Aβ) and tau, as well as glial contributions to various molecular and cellular pathways in AD pathogenesis. Herein, we review recent progress with respect to Aβ- and tau-associated mechanisms, and discuss glial dysfunction in AD with emphasis on neuronal and glial receptors that mediate Aβ-induced toxicity. We also discuss other critical factors that may affect AD pathogenesis, including genetics, aging, variables related to environment, lifestyle habits, and describe the potential role of apolipoprotein E (APOE), viral and bacterial infection, sleep, and microbiota. Although we have gained much towards understanding various aspects underlying this devastating neurodegenerative disorder, greater commitment towards research in molecular mechanism, diagnostics and treatment will be needed in future AD research.

Mendelian Randomization Study of Obesity and Cerebrovascular Disease

OBJECTIVE

To systematically investigate causal relationships between obesity and cerebrovascular disease and the extent to which hypertension and hyperglycemia mediate the effect of obesity on cerebrovascular disease.

METHODS

We used summary statistics from genome-wide association studies for body mass index (BMI), waist-to-hip ratio (WHR), and multiple cerebrovascular disease phenotypes. We explored causal associations with 2-sample Mendelian randomization (MR) accounting for genetic covariation between BMI and WHR, and we assessed what proportion of the association between obesity and cerebrovascular disease was mediated by systolic blood pressure (SBP) and blood glucose levels, respectively.

RESULTS

Genetic predisposition to higher BMI did not increase the risk of cerebrovascular disease. In contrast, for each 10% increase in WHR there was a 75% increase (95% confidence interval [CI] = 44-113%) in risk for large artery ischemic stroke, a 57% (95% CI = 29-91%) increase in risk for small vessel ischemic stroke, a 197% increase (95% CI = 59-457%) in risk of intracerebral hemorrhage, and an increase in white matter hyperintensity volume (β = 0.11, 95% CI = 0.01-0.21). These WHR associations persisted after adjusting for genetic determinants of BMI. Approximately one-tenth of the observed effect of WHR was mediated by SBP for ischemic stroke (proportion mediated: 12%, 95% CI = 4-20%), but no evidence of mediation was found for average blood glucose.

INTERPRETATION

Abdominal adiposity may trigger causal pathological processes, partially independent from blood pressure and totally independent from glucose levels, that lead to cerebrovascular disease. Potential targets of these pathological processes could represent novel therapeutic opportunities for stroke. ANN NEUROL 2020;87:516-524.

Therapeutic Development of Apolipoprotein E Mimetics for Acute Brain Injury: Augmenting Endogenous Responses to Reduce Secondary Injury

Over the last few decades, increasing evidence demonstrates that the neuroinflammatory response is a double-edged sword. Although overly robust inflammatory responses may exacerbate secondary tissue injury, inflammatory processes are ultimately necessary for recovery. Traditional drug discovery often relies on reductionist approaches to isolate and modulate specific intracellular pathways believed to be involved in disease pathology. However, endogenous brain proteins are often pleiotropic in order to regulate neuroinflammation and recovery mechanisms. Thus, a process of "backward translation" aims to harness the adaptive properties of endogenous proteins to promote earlier and greater recovery after acute brain injury. One such endogenous protein is apolipoprotein E (apoE), the primary apolipoprotein produced in the brain. Robust preclinical and clinical evidence demonstrates that endogenous apoE produced within the brain modulates the neuroinflammatory response of the acutely injured brain. Thus, one innovative approach to improve outcomes following acute brain injury is administration of exogenous apoE-mimetic drugs optimized to cross the blood-brain barrier. In particular, one promising apoE mimetic peptide, CN-105, has demonstrated efficacy across a wide variety of preclinical models of brain injury and safety and feasibility in early-phase clinical trials. Preclinical and clinical evidence for apoE's neuroprotective effects and downregulation of neuroinflammatory and the resulting translational therapeutic development strategy for an apoE-based therapeutic are reviewed.

Translational Genomics in Neurocritical Care: a Review

Translational genomics represents a broad field of study that combines genome and transcriptome-wide studies in humans and model systems to refine our understanding of human biology and ultimately identify new ways to treat and prevent disease. The approaches to translational genomics can be broadly grouped into two methodologies, forward and reverse genomic translation. Traditional (forward) genomic translation begins with model systems and aims at using unbiased genetic associations in these models to derive insight into biological mechanisms that may also be relevant in human disease. Reverse genomic translation begins with observations made through human genomic studies and refines these observations through follow-up studies using model systems. The ultimate goal of these approaches is to clarify intervenable processes as targets for therapeutic development. In this review, we describe some of the approaches being taken to apply translational genomics to the study of diseases commonly encountered in the neurocritical care setting, including hemorrhagic and ischemic stroke, traumatic brain injury, subarachnoid hemorrhage, and status epilepticus, utilizing both forward and reverse genomic translational techniques. Further, we highlight approaches in the field that could be applied in neurocritical care to improve our ability to identify new treatment modalities as well as to provide important information to patients about risk and prognosis.

Racial/ethnic disparities in the risk of intracerebral hemorrhage recurrence

OBJECTIVE

To estimate the risk of intracerebral hemorrhage (ICH) recurrence in a large, diverse, US-based population and to identify racial/ethnic and socioeconomic subgroups at higher risk.

METHODS

We performed a longitudinal analysis of prospectively collected claims data from all hospitalizations in nonfederal California hospitals between 2005 and 2011. We used validated diagnosis codes to identify nontraumatic ICH and our primary outcome of recurrent ICH. California residents who survived to discharge were included. We used log-rank tests for unadjusted analyses of survival across racial/ethnic groups and multivariable Cox proportional hazards regression to determine factors associated with risk of recurrence after adjusting for potential confounders.

RESULTS

We identified 31,355 California residents with first-recorded ICH who survived to discharge, of whom 15,548 (50%) were white, 6,174 (20%) were Hispanic, 4,205 (14%) were Asian, and 2,772 (9%) were black. There were 1,330 recurrences (4.1%) over a median follow-up of 2.9 years (interquartile range 3.8). The 1-year recurrence rate was 3.0% (95% confidence interval [CI] 2.8%-3.2%). In multivariable analysis, black participants (hazard ratio [HR] 1.22; 95% CI 1.01-1.48; p = 0.04) and Asian participants (HR 1.29; 95% CI 1.10-1.50; p = 0.001) had a higher risk of recurrence than white participants. Private insurance was associated with a significant reduction in risk compared to patients with Medicare (HR 0.60; 95% CI 0.50-0.73; p < 0.001), with consistent estimates across racial/ethnic groups.

CONCLUSIONS

Black and Asian patients had a higher risk of ICH recurrence than white patients, whereas private insurance was associated with reduced risk compared to those with Medicare. Further research is needed to determine the drivers of these disparities.

Cerebral amyloid angiopathy and Alzheimer disease - one peptide, two pathways

The shared role of amyloid-β (Aβ) deposition in cerebral amyloid angiopathy (CAA) and Alzheimer disease (AD) is arguably the clearest instance of crosstalk between neurodegenerative and cerebrovascular processes. The pathogenic pathways of CAA and AD intersect at the levels of Aβ generation, its circulation within the interstitial fluid and perivascular drainage pathways and its brain clearance, but diverge in their mechanisms of brain injury and disease presentation. Here, we review the evidence for and the pathogenic implications of interactions between CAA and AD. Both pathologies seem to be driven by impaired Aβ clearance, creating conditions for a self-reinforcing cycle of increased vascular Aβ, reduced perivascular clearance and further CAA and AD progression. Despite the close relationship between vascular and plaque Aβ deposition, several factors favour one or the other, such as the carboxy-terminal site of the peptide and specific co-deposited proteins. Amyloid-related imaging abnormalities that have been seen in trials of anti-Aβ immunotherapy are another probable intersection between CAA and AD, representing overload of perivascular clearance pathways and the effects of removing Aβ from CAA-positive vessels. The intersections between CAA and AD point to a crucial role for improving vascular function in the treatment of both diseases and indicate the next steps necessary for identifying therapies.

Genetic risk of Spontaneous intracerebral hemorrhage: Systematic review and future directions

BACKGROUND

Although highly heritable, few genes have been linked to spontaneous intracerebral hemorrhage (SICH), which does not currently have any evidence-based disease-modifying therapy. Individuals of African ancestry are especially susceptible to SICH, even more so for indigenous Africans. We systematically reviewed the genetic variants associated with SICH and examined opportunities for rapidly advancing SICH genomic research for precision medicine.

METHOD

We searched the National Human Genome Research Institute-European Bioinformatics Institute (NHGRI-EBI) Genome Wide Association Study (GWAS) catalog and PubMed for original research articles on genetic variants associated with SICH as of 15 June 2019 using the PRISMA guideline.

RESULTS

Eight hundred and sixty-four articles were identified using pre-specified search criteria, of which 64 met the study inclusion criteria. Among eligible articles, only 9 utilized GWAS approach while the rest were candidate gene studies. Thirty-eight genetic loci were found to be variously associated with the risk of SICH, hematoma volume, functional outcome and mortality, out of which 8 were from GWAS including APOE, CR1, KCNK17, 1q22, CETP, STYK1, COL4A2 and 17p12. None of the studies included indigenous Africans.

CONCLUSION

Given this limited information on the genetic contributors to SICH, more genomic studies are needed to provide additional insights into the pathophysiology of SICH, and develop targeted preventive and therapeutic strategies. This call for additional investigation of the pathogenesis of SICH is likely to yield more discoveries in the unexplored indigenous African populations which also have a greater predilection.

A Case of Cerebral Amyloid Angiopathy-Related Inflammation With the Rare Apolipoprotein ε2/ε2 Genotype

Cerebral amyloid angiopathy (CAA)-related inflammation (CAA-RI) is a rare CAA variant characterized by acute or subacute encephalopathy, headache, epilepsy, or focal neurological deficits. Radiologically, CAA-RI presents with widespread white matter lesions on brain magnetic resonance imaging (MRI) in addition to the hemorrhagic imaging features of CAA. Previous studies have found that the apolipoprotein E (ApoE) ε4 allele and ε4/ε4 genotype were over-represented in CAA-RI. The role of the ApoE ε2 allele in CAA-RI, however, is largely unknown, partly due to the rarity of the ε2/ε2 genotype in the general population. The authors report the first case of CAA-RI with the rare ApoE ε2/ε2 genotype. The patient presented with mild clinical symptoms but striking neuroimaging abnormalities. The response to small-dose glucocorticoids was satisfactory. Because ApoE ε2 promotes amyloid β accumulation and fibrinoid necrosis in the cerebral vasculature, the ε2/ε2 genotype, similar to ε4/ε4, may also be a precipitating factor for CAA-RI. To clarify the role of ApoE ε2 in CAA-RI, studies with large sample sizes investigating whether ε2 is more common in patients with CAA-RI than in those with CAA only are warranted.