APOE genotype and extent of bleeding and outcome in lobar intracerebral haemorrhage: a genetic association study

Association of APOE genotype with CT markers of cerebral amyloid angiopathy in spontaneous intracerebral haemorrhage

BACKGROUND AND OBJECTIVE

We investigated the association of APOE alleles with CT-based cerebral amyloid angiopathy (CAA) markers including subarachnoid extension (SAE) and finger-like projection (FLP).

METHODS

We included patients with acute primary supratentorial intracerebral haemorrhage (ICH) from a multicentre cohort in China. First, the association of APOE with ICH location (lobar vs non-lobar) was evaluated. Next, the relationships of APOE with SAE, FLP, and the coexistence of the two (SAE+FLP) were evaluated.

RESULTS

533 patients with supratentorial ICH were enrolled. Among them were 138 patients with lobar ICH and 395 with non-lobar ICH. Compared with the non-lobar group, APOE ε4 (OR 1.894, 95% CI 1.138 to 3.154, p=0.014) and ε2/ε4 (OR 6.098, 95% CI 1.414 to 26.293, p=0.015) were associated with lobar ICH. With regard to CAA markers, APOE ε2 was associated with SAE (OR 2.109, 95% CI 1.167 to 3.810, p=0.013), ε4 was associated with FLP and SAE+FLP (OR 3.026, 95% CI 1.353 to 6.767, p=0.007; OR 3.514, 95% CI 1.485 to 8.316, p=0.004, respectively) and ε2/ε4 was associated with all three factors (SAH: OR 7.599, 95% CI 1.764 to 32.734, p=0.006; FLP: OR 20.333, 95% CI 3.278 to 126.137, p=0.001; SAE+FLP: OR 30.568, 95% CI 4.460 to 209.503, p<0.001) after adjusting for age, and remained significant after adjusting for age and ICH volume.

CONCLUSION

In patients with spontaneous supratentorial ICH, APOE ε2 and ε4 alleles were associated with SAE and FLP, respectively, suggesting APOE allele-specific effects on CT markers of CAA and their potential mechanisms.

The relationship between Alzheimer's disease and intracerebral hemorrhage based on Mendelian randomization

BackgroundTraditional epidemiologic studies suggest that Alzheimer's disease (AD) may be associated with intracerebral hemorrhage (ICH).ObjectiveTo explore whether there is a causal relationship between AD and ICH and the underlying mechanisms involved.MethodsMendelian randomization (MR) approach was used to explore causal relationships. The genetic instrumental variables of the candidate genetic instrumental variable AD were obtained from genome-wide association studies. The inverse variance weighted method was the primary method for MR analysis and meta-analysis. The obtained single nucleotide polymorphisms were analyzed for corresponding genes for subsequent pathway enrichment and protein-protein interaction analysis.ResultsFor the single AD dataset, our MR analysis of the AD datasets versus the ICH datasets revealed a genetically predicted causal relationship between AD and ICH (OR 5.947, 95%CI 1.165-30.356, pIVW = 0.032). In addition, the MR-Egger method and MR-PRESSO method revealed no horizontal pleiotropic effect of AD on the risk of ICH. Meta-analysis of each dataset using IVW revealed a final calculated OR of 1.08 (95%CI 1.02-1.15, p = 0.01). Subsequent pathway enrichment analysis revealed that the corresponding genes were involved mainly in the metabolic process of amyloid-β (Aβ) and negatively regulated Aβ formation. In the PPI network analysis, proteins such as ApoE, SROL1, CLU, ABCA7, and AβPP were found to be closely related and located in the key position of the center.ConclusionsWe verified the causal relationship between AD and ICH via MR, and identified the possible pathological mechanisms involved. We also discovered that Aβ plays an important role in this process.

Genetic Variants ε2 and ε4 of APOE Predict Mortality and Poor Outcome Independently in Spontaneous Intracerebral Hemorrhage Within the Chinese Han Population

The heightened mortality and disability rates, coupled with restricted neurological recovery post intracerebral hemorrhage (ICH), have sparked considerable attention toward its treatment and results. Simultaneously, the influence of the APOE gene on ICH prognosis has been well-documented. This research aimed to explore the relationship between specific APOE alleles in the present cohort and the incidences of mortality, recurrence, and adverse prognosis, as determined by neurological function assessments in ICH patients. Data on patients diagnosed with ICH and hospitalized in the Department of Neurology at our institution from October 2021 to March 2022 were collected, including determining their APOE genotypes. A 1-year follow-up was conducted to evaluate mortality, ICH recurrence, and modified Rankin Scale (mRS) scores at 3 and 12 months. Poor prognosis was defined as an mRS score of ≥ 3. Initially, we analyzed the relationships between different APOE alleles and mortality, recurrence, and poor prognosis. Subsequently, we explored additional factors influencing each prognostic outcome and conducted multivariate analysis to identify independent risk factors. An analysis was conducted on 289 patients diagnosed with ICH. The presence of the ε2 allele was found to be a significant independent predictor for unfavorable outcomes at both 3 months (p = 0.022, OR = 2.138, 95% CI [2.041, 3.470]) and 1 year (p = 0.020, OR = 5.116, 95% CI [5.044, 5.307]). Moreover, the ε4 allele was established as an independent risk factor for ICH recurrence within 1 year (p = 0.025, OR = 2.326, 95% CI [1.163, 2.652]), as well as for mortality at 3 months (p = 0.037, OR = 4.250, 95% CI [4.068, 4.920]) and 1 year (p = 0.023, OR = 4.109, 95% CI [4.016, 4.739]). In conclusions, Both APOE ε2 and ε4 variants independently heighten mortality risk, recurrence, and poor prognosis after ICH. The substantial influence underscores the need for additional investigation into the impact of APOE genotype on ICH prognosis.

Apolipoprotein E genotype is associated with island sign in lobar intracerebral hemorrhage

Background

The island sign is a predictor of hematoma expansion and worse outcomes in patients of spontaneous primary intracerebral hemorrhage (ICH). The biological mechanism of the island sign remains unclear, but its presence might be influenced by the underlying vasculopathy related to Apolipoprotein E (APOE) genotypes. Therefore, we aimed to research the association between APOE genotypes and the island sign.

Methods

We enrolled patients with primary supratentorial ICH in a multicenter cohort in northern China with baseline noncontrast CT images performed within 14 days after symptoms onset and APOE genotype available. The island sign was rated on the CT images according to validated criteria. Univariable and multivariable analyses were used to identify the association between APOE genotypes and the island sign, stratified by the ICH location.

Results

Among 460 patients enrolled, 122 were lobar ICH. In all patients, after adjusting for age, sex, hypertension, and time to CT, the presence of the APOE ε4 allele (OR 2.020, 95% CI 1.064-3.834, p = 0.032) was associated with the island sign, whereas the presence of the APOE ε2 allele (OR 0.734, 95% CI 0.339-1.593, p = 0.435) was not. After stratifying by ICH location, multivariable analysis revealed that APOE ε4 (OR 3.510, 95% CI 1.393-8.846, p = 0.008), rather than ε2 (OR 0.621, 95% CI 0.203-1.901, p = 0.404), was associated with the island sign in lobar ICH patients. Neither the ε2 nor the ε4 allele was associated with the island sign among nonlobar ICH patients.

Conclusion

The APOE ε4 allele was associated with the island sign in lobar ICH patients. Our findings indicate that the presence of the island sign may be influenced by the underlying vasculopathy related to APOE ε4, which increases amyloid deposition in the cerebral vasculature.

Subarachnoid hemorrhage and finger-like projection predict recurrence in patients with lobar intracerebral hemorrhage

BACKGROUND AND PURPOSE

Lobar intracerebral hemorrhage (ICH) is associated with a high risk of recurrence, particularly in elderly patients, where cerebral amyloid angiopathy (CAA) is often the primary cause. Diagnostic markers of CAA-related ICH, including subarachnoid hemorrhage (SAH) and finger-like projection (FLP), have recently been developed. Here, we aimed to explore the associations between SAH, FLP and the risk of ICH recurrence in lobar ICH patients.

METHODS

We analyzed data from consecutive lobar ICH patients using the method of cohort study. We divided them into 4 groups on the basis of the presence or absence of SAH and FLP on CT imaging. The Cox regression model and competing risk model were used to analyze the associations of SAH and FLP with the risk of ICH recurrence at 1 year.

RESULTS

In total, 353 patients with lobar ICH (median age 74 [62, 81] years, 57.2% male) were included in our study. During follow-up, recurrence occurred in 34 patients (10.6%), and 90 patients (28.1%) died. The competing risk model revealed that patients in the SAH + FLP- (HR 2.88, 95% CI 1.12-7.44, p = 0.03) and SAH + FLP + (HR 8.38, 95% CI 3.40-20.66, p < 0.001) groups had higher risks of ICH recurrence within 1 year than did those in the SAH-FLP- group.

CONCLUSION

SAH is an important predictor of ICH recurrence, and this predictive ability is further enhanced when FLP is present. These findings suggest that SAH, especially with FLP, can be a valuable tool for assessing prognosis in lobar ICH patients.

Association between apolipoprotein E gene polymorphism and early MR findings in individuals with acute intracerebral hemorrhage: A retrospective cohort analysis

OBJECTIVE

The Apolipoprotein E (APOE) gene plays a significant role in the development and prognosis of intracerebral hemorrhage (ICH). Imaging features identified within 48 h of ICH onset, particularly on magnetic resonance imaging (MRI), are indicative of cerebral small vessel diseases (CSVD). Our study aimed to assess these imaging characteristics and investigate their association with the APOE gene among ICH patients.

METHODS

Clinical and imaging data from patients meeting specific inclusion and exclusion criteria from October 2021 to March 2022 were collected. MR signs or scores were evaluated following international accreditation standards and then analyzed in connection with the APOE allele genes.

RESULTS

In a cohort of 220 patients, ε2 was identified as an independent risk factor for the "multiple subcortical spots" sign (OR = 13.29, 95% CI 1.88-22.59). Furthermore, ε4 emerged as an independent risk factor for the presence of perivascular space (PVS) in the centrum semiovale (OR = 2.46, 95% CI 1.03-5.89) and basal ganglia (OR = 2.64, 95% CI 1.10-6.35), as well as for cerebral microbleeds (CMB) across all locations (OR = 2.38, 95% CI 1.15-6.97), lobar CMB (OR = 2.92, 95% CI 1.11-7.65), and deep CMB (OR = 2.29, 95% CI 1.12-8.67).

CONCLUSION

The association between APOE ɛ2 and ɛ4 alleles and the presence of "subcortical multiple spots," "PVS," and "CMB" indirectly implies the potential role of APOE gene-related pathological changes in the progression of ICH and small vessel pathology.

Oral microbiome and nitric oxide biomarkers in older people with mild cognitive impairment and APOE4 genotype

Apolipoprotein E4 (APOE4) genotype and nitric oxide (NO) deficiency are risk factors for age-associated cognitive decline. The oral microbiome plays a critical role in maintaining NO bioavailability during aging. The aim of this study was to assess interactions between the oral microbiome, NO biomarkers, and cognitive function in 60 participants with mild cognitive impairment (MCI) and 60 healthy controls using weighted gene co-occurrence network analysis and to compare the oral microbiomes between APOE4 carriers and noncarriers in a subgroup of 35 MCI participants. Within the MCI group, a high relative abundance of Neisseria was associated with better indices of cognition relating to executive function (Switching Stroop, rs = 0.33, P = 0.03) and visual attention (Trail Making, rs = -0.30, P = 0.05), and in the healthy group, Neisseria correlated with working memory (Digit Span, rs = 0.26, P = 0.04). High abundances of Haemophilus (rs = 0.38, P = 0.01) and Haemophilus parainfluenzae (rs = 0.32, P = 0.03), that co-occurred with Neisseria correlated with better scores on executive function (Switching Stroop) in the MCI group. There were no differences in oral nitrate (P = 0.48) or nitrite concentrations (P = 0.84) between the MCI and healthy groups. Linear discriminant analysis Effect Size identified Porphyromonas as a predictor for MCI and Prevotella intermedia as a predictor of APOE4-carrier status. The principal findings of this study were that a greater prevalence of oral P. intermedia is linked to elevated genetic risk for dementia (APOE4 genotype) in individuals with MCI prior to dementia diagnosis and that interventions that promote the oral Neisseria-Haemophilus and suppress Prevotella-dominated modules have potential for delaying cognitive decline.

Effect of APOE gene on cerebral oxygen saturation, cerebral electrical activity and prognosis after intracerebral hemorrhage

Cerebral hemorrhage represents a severe neurological disorder with significant implications for patient health. Numerous factors play a crucial role in determining the prognosis of this condition. In recent years, research has highlighted the polymorphism of the apolipoprotein E (APOE) gene as being closely associated with cerebrovascular diseases and the recovery of neurological functions. This study aims to explore the influence of APOE gene polymorphism on cerebral oxygen saturation, cerebral electrical activity, and the clinical prognosis of patients experiencing cerebral hemorrhage. The goal is to identify potential new biomarkers that could enhance the management and treatment of individuals who have suffered from this type of bleed in the brain.To investigate this relationship, the study analyzed the ε2, ε3, and ε4 alleles of the APOE gene through gene sequencing techniques. Measurements of cerebral oxygen saturation and electrical brain activity were conducted using specialized equipment including brain oxygen monitors and electroencephalography (EEG) devices. Additionally, detailed clinical data were gathered, encompassing neurological function assessments and the duration of recovery for each patient.A comparative analysis was performed to assess the cerebral oxygen saturation levels, EEG characteristics, and overall prognosis associated with the different APOE genotypes. The findings indicated that patients carrying the APOE ε4 allele exhibited significantly impaired cerebral oxygen metabolism and diminished electrical activity in the initial stages of intracerebral hemorrhage. This impairment potentially results in a worse prognostic outlook when compared to individuals who are non-carriers of the APOE ε4 allele. Furthermore, the relationship between the pulsatility index (PR) and regional cerebral oxygen saturation (rScO2) was found to be negatively correlated. Specifically, patients with intracerebral hemorrhage who exhibited elevated PR levels alongside reduced rScO2 demonstrated poorer clinical outcomes.

Stroke genetics and how it Informs novel drug discovery

INTRODUCTION

Stroke is one of the main causes of death and disability worldwide. Nevertheless, despite the global burden of this disease, our understanding is limited and there is still a lack of highly efficient etiopathology-based treatment. It is partly due to the complexity and heterogenicity of the disease. It is estimated that around one-third of ischemic stroke is heritable, emphasizing the importance of genetic factors identification and targeting for therapeutic purposes.

AREAS COVERED

In this review, the authors provide an overview of the current knowledge of stroke genetics and its value in diagnostics, personalized treatment, and prognostication.

EXPERT OPINION

As the scale of genetic testing increases and the cost decreases, integration of genetic data into clinical practice is inevitable, enabling assessing individual risk, providing personalized prognostic models and identifying new therapeutic targets and biomarkers. Although expanding stroke genetics data provides different diagnostics and treatment perspectives, there are some limitations and challenges to face. One of them is the threat of health disparities as non-European populations are underrepresented in genetic datasets. Finally, a deeper understanding of underlying mechanisms of potential targets is still lacking, delaying the application of novel therapies into routine clinical practice.

Apolipoprotein E ɛ2 Is Associated with the White Matter Hyperintensity Multispot Pattern in Spontaneous Intracerebral Hemorrhage

The white matter hyperintensity (WMH) multispot pattern, as multiple punctate subcortical foci, could differentiate cerebral amyloid angiopathy (CAA) from hypertensive arteriolopathy. Nevertheless, the pathophysiology underlying the multispot sign is still inexplicit. We aimed to explore risk factors for multispot patterns in cerebral small vessel disease (CSVD)-related intracerebral hemorrhage (ICH). Between June 2018 and January 2020, we retrospectively rated the WMH multispot pattern while blinded to our prospective spontaneous ICH cohort's clinical data. Demographic, genetic, and neuroimaging characteristics were applied in establishing the multispot pattern models via multiple logistic regression. In total, 268 participants were selected from our cohort. The possession of apolipoprotein E (APOE) ε2 (P = 0.051) was associated with multispot WMH in univariate analysis. Multispot WMHs were accompanied by multiple CAA features, such as centrum semiovale (CSO)-perivascular space (PVS) predominance (P = 0.032) and severe CSO-PVS (P < 0.001). After adjusting for confounding factors, APOE ε2 possession (OR 2.99, 95% CI [1.07, 8.40]; P = 0.037), severe CSO-PVS (OR 2.39, 95% CI [1.09, 5.26]; P = 0.031), and large posterior subcortical patches (P = 0.001) were independently correlated with the multispot pattern in multivariate analysis. Moreover, APOE ε2 possession (OR 4.34, 95% CI [1.20, 15.62]; P = 0.025) and severe CSO-PVS (OR 3.39, 95% CI [1.23, 9.34]; P = 0.018) remained statistically significant among the participants older than 55 years of age and with categorizable CSVD. APOE ε2 and severe CSO-PVS contribute to the presence of WMH multispot patterns. Because the multispot pattern is a potential diagnostic biomarker in CAA, genetics-driven effects shed light on its underlying vasculopathy. Clinical Trial Registration: URL- http://www.chictr.org.cn . Unique identifier: ChiCTR-ROC-2000039365. Registration date 2020/10/24 (retrospectively registered).

Incident Dementia After Spontaneous Intracerebral Hemorrhage

 Post-stroke cognitive impairment and dementia (PSCID) is a complication that affects long-term functional outcomes after stroke. Studies on dementia after long-term follow-up in stroke have focused predominantly on ischemic stroke, which may be different from the development of dementia after spontaneous intracerebral hemorrhage (ICH). In this review, we summarize the existing data and hypotheses on the development of dementia after spontaneous ICH, review the management of post-ICH dementia, and suggest areas for future research. Dementia after spontaneous ICH has a cumulative incidence of up to 32.0-37.4% at 5 years post-ICH. Although the pathophysiology of post-ICH dementia has not been fully understood, two main theoretical frameworks can be considered: 1) the triggering role of ICH (both primary and secondary brain injury) in precipitating cognitive decline and dementia; and 2) the contributory role of pre-existing brain pathology (including small vessel disease and neurodegenerative pathology), reduced cognitive reserve, and genetic factors predisposing to cognitive dysfunction. These pathophysiological pathways may have synergistic effects that converge on dysfunction of the neurovascular unit and disruptions in functional connectivity leading to dementia post-ICH. Management of post-ICH dementia may include screening and monitoring, cognitive therapy, and pharmacotherapy. Non-invasive brain stimulation is an emerging therapeutic modality under investigation for safety and efficacy. Our review highlights that there remains a paucity of data and standardized reporting on incident dementia after spontaneous ICH. Further research is imperative for determining the incidence, risk factors, and pathophysiology of post-ICH dementia, in order to identify new therapies for the treatment of this debilitating condition.

Genome-wide analysis identified abundant genetic modulators of contributions of the apolipoprotein E alleles to Alzheimer's disease risk

INTRODUCTION

The apolipoprotein E (APOE) ε2 and ε4 alleles have beneficial and adverse impacts on Alzheimer's disease (AD), respectively, with incomplete penetrance, which may be modulated by other genetic variants.

METHODS

We examined whether the associations of the APOE alleles with other polymorphisms in the genome can be sensitive to AD-affection status.

RESULTS

We identified associations of the ε2 and ε4 alleles with 314 and 232 polymorphisms, respectively. Of them, 35 and 31 polymorphisms had significantly different effects in AD-affected and -unaffected groups, suggesting their potential involvement in the AD pathogenesis by modulating the effects of the ε2 and ε4 alleles, respectively. Our survival-type analysis of the AD risk supported modulating roles of multiple group-specific polymorphisms. Our functional analysis identified gene enrichment in multiple immune-related biological processes, for example, B cell function.

DISCUSSION

These findings suggest involvement of local and inter-chromosomal modulators of the effects of the APOE alleles on the AD risk.

APOE and Cerebral Small Vessel Disease Markers in Patients With Intracerebral Hemorrhage

BACKGROUND AND OBJECTIVE

We investigated the associations between the APOE genotype, intracerebral hemorrhage (ICH), and neuroimaging markers of cerebral amyloid angiopathy (CAA).

METHODS

We included patients from a prospective, multicenter UK observational cohort study of patients with ICH and representative UK population controls. First, we assessed the association of the APOE genotype with ICH (compared with controls without ICH). Second, among patients with ICH, we assessed the association of APOE status with the hematoma location (lobar or deep) and brain CT markers of CAA (finger-like projections [FLP] and subarachnoid extension [SAE]).

RESULTS

We included 907 patients with ICH and 2,636 controls. The mean age was 73.2 (12.4 SD) years for ICH cases vs 69.6 (0.2 SD) for population controls; 50.3% of cases and 42.1% of controls were female. Compared with controls, any APOE ε2 allele was associated with all ICH (lobar and nonlobar) and lobar ICH on its own in the dominant model (OR 1.38, 95% CI 1.13-1.7, p = 0.002 and OR 1.50, 95% CI 1.1-2.04, p = 0.01, respectively) but not deep ICH in an age-adjusted analyses (OR 1.26, 95% CI 0.97-1.63, p = 0.08). In the cases-only analysis, the APOE ε4 allele was associated with lobar compared with deep ICH in an age-adjusted analyses (OR 1.56, 95% CI 1.1-2.2, p = 0.01). When assessing CAA markers, APOE alleles were independently associated with FLP (ε4: OR 1.74, 95% CI 1.04-2.93, p = 0.04 and ε2/ε4: 2.56, 95% CI 0.99-6.61, p = 0.05). We did not find an association between APOE alleles and SAE.

DISCUSSION

We confirmed associations between APOE alleles and ICH including lobar ICH. Our analysis shows selective associations between APOE ε2 and ε4 alleles with FLP, a CT marker of CAA. Our findings suggest that different APOE alleles might have diverging influences on individual neuroimaging biomarkers of CAA-associated ICH.

Clinical neuroimaging in intracerebral haemorrhage related to cerebral small vessel disease: contemporary practice and emerging concepts

INTRODUCTION

About 80% of all non-traumatic intracerebral haemorrhage (ICH) are caused by the sporadic cerebral small vessel diseases deep perforator arteriopathy (DPA, also termed hypertensive arteriopathy or arteriolosclerosis) and cerebral amyloid angiopathy (CAA), though these frequently co-exist in older people. Contemporary neuroimaging (MRI and CT) detects an increasing spectrum of haemorrhagic and non-haemorrhagic imaging biomarkers of small vessel disease which may identify the underlying arteriopathies.

AREAS COVERED

We discuss biomarkers for cerebral small vessel disease subtypes in ICH, and explore their implications for clinical practice and research.

EXPERT OPINION

ICH is not a single disease, but results from a defined range of vascular pathologies with important implications for prognosis and treatment. The terms "primary" and "hypertensive" ICH are poorly defined and should be avoided, as they encourage incomplete investigation and classification. Imaging-based criteria for CAA will show improved diagnostic accuracy, but specific imaging biomarkers of DPA are needed. Ultra-high-field 7T-MRI using structural and quantitative MRI may provide further insights into mechanisms and pathophysiology of small vessel disease. We expect neuroimaging biomarkers and classifications to allow personalized treatments (e.g. antithrombotic drugs) in clinical practice and to improve patient selection and monitoring in trials of targeted therapies directed at the underlying arteriopathies.

Intracerebral Hemorrhage Genetics

Intracerebral hemorrhage (ICH) is a devastating type of stroke, frequently resulting in unfavorable functional outcomes. Up to 15% of stroke patients experience ICH and approximately half of those have a lethal outcome within a year. Considering the huge burden of ICH, timely prevention and optimized treatment strategies are particularly relevant. Nevertheless, ICH management options are quite limited, despite thorough research. More and more trials highlight the importance of the genetic component in the pathogenesis of ICH. Apart from distinct monogenic disorders of familial character, mostly occurring in younger subjects, there are numerous polygenic risk factors, such as hypertension, neurovascular inflammation, disorders of lipid metabolism and coagulation cascade, and small vessel disease. In this paper we describe gene-related ICH types and underlying mechanisms. We also briefly discuss the emerging treatment options and possible clinical relevance of the genetic findings in ICH management. Although existing data seems of more theoretical and scientific value so far, a growing body of evidence, combined with rapidly evolving experimental research, will probably serve clinicians in the future.

Vascular Dysfunction Is Central to Alzheimer's Disease Pathogenesis in APOE e4 Carriers

Alzheimer's disease (AD) is the most common form of dementia and the leading risk factor, after age, is possession of the apolipoprotein E epsilon 4 allele (APOE4). Approximately 50% of AD patients carry one or two copies of APOE4 but the mechanisms by which it confers risk are still unknown. APOE4 carriers are reported to demonstrate changes in brain structure, cognition, and neuropathology, but findings have been inconsistent across studies. In the present study, we used multi-modal data to characterise the effects of APOE4 on the brain, to investigate whether AD pathology manifests differently in APOE4 carriers, and to determine if AD pathomechanisms are different between carriers and non-carriers. Brain structural differences in APOE4 carriers were characterised by applying machine learning to over 2000 brain MRI measurements from 33,384 non-demented UK biobank study participants. APOE4 carriers showed brain changes consistent with vascular dysfunction, such as reduced white matter integrity in posterior brain regions. The relationship between APOE4 and AD pathology was explored among the 1260 individuals from the Religious Orders Study and Memory and Aging Project (ROSMAP). APOE4 status had a greater effect on amyloid than tau load, particularly amyloid in the posterior cortical regions. APOE status was also highly correlated with cerebral amyloid angiopathy (CAA). Bulk tissue brain transcriptomic data from ROSMAP and a similar dataset from the Mount Sinai Brain Bank showed that differentially expressed genes between the dementia and non-dementia groups were enriched for vascular-related processes (e.g., "angiogenesis") in APOE4 carriers only. Immune-related transcripts were more strongly correlated with AD pathology in APOE4 carriers with some transcripts such as TREM2 and positively correlated with pathology severity in APOE4 carriers, but negatively in non-carriers. Overall, cumulative evidence from the largest neuroimaging, pathology, and transcriptomic studies available suggests that vascular dysfunction is key to the development of AD in APOE4 carriers. However, further studies are required to tease out non-APOE4-specific mechanisms.

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.

Association Between Partial Pressure of Carbon Dioxide and Immediate Seizures in Patients With Primary Intracerebral Hemorrhage: A Propensity-Matched Analysis

Purpose

To explore the value of partial pressure of carbon dioxide (PaCO₂) levels in arterial blood for predicting immediate seizures (ISs) in patients with primary intracerebral hemorrhage (ICH).

Methods

Demographic information and clinical data from patients with primary ICH were prospectively collected, including arterial blood gas analysis. Immediate seizures (ISs) were determined as seizures in the first 24 h after admission. Univariate and multivariate analyses were performed to assess the association of PaCO₂ levels with ISs. Propensity-score matching (PSM) analyses were adopted to reduce the baseline difference between ISs and non-ISs groups.

Results

A total of 596 patients with primary ICH were initially screened in this clinical study, 368 of whom fulfilled all the inclusion criteria [mean age, (60.46 ±12.78) years; 57.9% female patients]. ISs occurred in 30 of the 368 (8.15%) patients with primary ICH of this cohort. Patients with ISs had significantly lower PaCO₂ levels [34.35(32.38–37.53) vs. 39.45(35.90–43.43), mmHg, p < 0.001] and were younger than those without ISs [(54.57±12.15 vs. 60.99 ±12.72) years, p = 0.008]. Multivariate analysis showed that lower initial PaCO₂ (≤37.2 mmHg) level was a significant independent predictor of ISs [odds ratios (OR) 0.141, 95% confidence interval (CI) 0.057–0.351, p < 0.001], as well as younger age (OR 0.961, 95% CI 0.928–0.995, p = 0.023) and hematoma expansion (OR 0.340, 95% CI 0.134–0.863, p = 0.023). Receiver operating characteristic curve (ROC) analysis demonstrated that the optimal cutoff value of PaCO₂ level for predicting ISs was 37.20 mmHg in patients with primary ICH (the area under the curve (AUC) was 0.760 with a corresponding sensitivity of 76.67% and specificity of 67.46%, 95%CI = 0.713–0.802, p < 0.001). After PSM, the matched ISs group had significantly lower PaCO₂ levels compared with the matched non-ISs group [34.45(32.43–38.18) vs. 41.75(35.85–43.98) mmHg, p < 0.05] in the univariate analysis. The lower initial PaCO₂ level was still independent of ISs following primary ICH.

Conclusions

The lower initial PaCO₂ level was associated with an increased risk of ISs in patients with primary ICH.

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.

EARLY CONSIDERATIONS OF GENETICS IN APHASIA REHABILITATION: A NARRATIVE REVIEW

Background

Early investigations linking language and genetics were focused on the evolution of human communication in populations with developmental speech and language disorders. Recently, studies suggest that genes may also modulate recovery from post-stroke aphasia.

Aims

Our goal is to review current literature related to the influence of genetics on post-stroke recovery, and the implications for aphasia rehabilitation. We describe candidate genes implicated by empirical findings and address additional clinical considerations.

Main Contribution

We describe existing evidence and mechanisms supporting future investigations into how genetic factors may modulate aphasia recovery and propose that two candidate genes, brain derived neurotrophic factor (BDNF) and apolipoprotein E (APOE), may be important considerations for future research assessing response to aphasia treatment. Evidence suggests that BDNF is important for learning, memory, and neuroplasticity. APOE influences cognitive functioning and memory in older individuals and has also been implicated in neural repair. Moreover, recent data suggest an interaction between specific alleles of the BDNF and APOE genes in influencing episodic memory.

Conclusions

Genetic influences on recovery from aphasia have been largely unexplored in the literature despite evidence that genetic factors influence behaviour and recovery from brain injury. As researchers continue to explore prognostic factors that may influence response to aphasia treatment, it is time for genetic factors to be considered as a source of variability. As the field moves in the direction of personalized medicine, eventually allied health professionals may utilize genetic profiles to inform treatment decisions and education for patients and care partners.

Mitochondrial DNA Copy Number as a Marker and Mediator of Stroke Prognosis: Observational and Mendelian Randomization Analyses

BACKGROUND AND OBJECTIVES

Low buffy coat mitochondrial DNA copy number (mtDNA-CN) is associated with incident risk of stroke and poststroke mortality; however, its prognostic utility has not been extensively explored. Our goal was to investigate whether low buffy coat mtDNA-CN is a marker and causal determinant of poststroke outcomes using epidemiologic and genetic studies.

METHODS

First, we performed association testing between baseline buffy coat mtDNA-CN measurements and 1-month poststroke outcomes in 3,498 cases of acute, first stroke from 25 countries from the international, multicenter case-control study Importance of Conventional and Emerging Risk Factors of Stroke in Different Regions and Ethnic Groups of the World (INTERSTROKE). Then, we performed 2-sample mendelian randomization analyses to evaluate potential causative effects of low mtDNA-CN on 3-month modified Rankin Scale (mRS) score. Genetic variants associated with mtDNA-CN levels were derived from the UK Biobank study (N = 383,476), and corresponding effects on 3-month mRS score were ascertained from the Genetics of Ischemic Stroke Functional Outcome (GISCOME; N = 6,021) study.

RESULTS

A 1-SD lower mtDNA-CN at baseline was associated with stroke severity (baseline mRS score: odds ratio [OR] 1.27, 95% confidence interval [CI] 1.19-1.36; p = 4.7 × 10-12). Independently of baseline stroke severity, lower mtDNA-CN was associated with increased odds of greater 1-month disability (ordinal mRS score: OR 1.16, 95% CI 1.08-1.24; p = 4.4 × 10-5), poor functional outcome status (mRS score 3-6 vs 0-2: OR 1.21, 95% CI 1.08-1.34; p = 6.9 × 10-4), and mortality (OR 1.35, 95% CI 1.14-1.59; p = 3.9 × 10-4). Subgroup analyses demonstrated consistent effects across stroke type, sex, age, country income level, and education level. In addition, mtDNA-CN significantly improved reclassification of poor functional outcome status (net reclassification index [NRI] score 0.16, 95% CI 0.08-0.23; p = 3.6 × 10-5) and mortality (NRI score 0.31, 95% CI 0.19-0.43; p = 1.7 × 10-7) beyond known prognosticators. With the use of independent datasets, mendelian randomization revealed that a 1-SD decrease in genetically determined mtDNA-CN was associated with increased odds of greater 3-month disability quantified by ordinal mRS score (OR 2.35, 95% CI 1.13-4.90; p = 0.02) and poor functional outcome status (OR 2.68, 95% CI 1.05-6.86; p = 0.04).

DISCUSSION

Buffy coat mtDNA-CN is a novel and robust marker of poststroke prognosis that may also be a causal determinant of poststroke outcomes.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that low buffy coat mtDNA-CN (>1 SD) was associated with worse baseline severity and 1-month outcomes in patients with ischemic or hemorrhagic stroke.

Genetics in aphasia recovery

Considerable research efforts have been exerted toward understanding the mechanisms underlying recovery in aphasia. However, predictive models of spontaneous and treatment-induced recovery remain imprecise. Some of the hitherto unexplained variability in recovery may be accounted for with genetic data. A few studies have examined the effects of the BDNF val66met polymorphism on aphasia recovery, yielding mixed results. Advances in the study of stroke genetics and genetics of stroke recovery, including identification of several susceptibility genes through candidate-gene or genome-wide association studies, may have implications for the recovery of language function. The current chapter discusses both the direct and indirect evidence for a genetic basis of aphasia recovery, the implications of recent findings within the field, and potential future directions to advance understanding of the genetics-recovery associations.

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.

Machine Learning and Precision Medicine in Emergency Medicine: The Basics

As machine learning (ML) and precision medicine become more readily available and used in practice, emergency physicians must understand the potential advantages and limitations of the technology. This narrative review focuses on the key components of machine learning, artificial intelligence, and precision medicine in emergency medicine (EM). Based on the content expertise, we identified articles from EM literature. The authors provided a narrative summary of each piece of literature. Next, the authors provided an introduction of the concepts of ML, artificial intelligence as an extension of ML, and precision medicine. This was followed by concrete examples of their applications in practice and research. Subsequently, we shared our thoughts on how to consume the existing research in these subjects and conduct high-quality research for academic emergency medicine. We foresee that the EM community will continue to adapt machine learning, artificial intelligence, and precision medicine in research and practice. We described several key components using our expertise.

CN-105 in Participants with Acute Supratentorial Intracerebral Hemorrhage (CATCH) Trial

BACKGROUND

Endogenous apolipoprotein (apo) E mediates neuroinflammatory responses and recovery after brain injury. Exogenously administered apoE-mimetic peptides effectively penetrate the central nervous system compartment and downregulate acute inflammation. CN-105 is a novel apoE-mimetic pentapeptide with excellent evidence of functional and histological improvement in preclinical models of intracerebral hemorrhage (ICH). The CN-105 in participants with Acute supraTentorial intraCerebral Hemorrhage (CATCH) trial is a first-in-disease-state multicenter open-label trial evaluating safety and feasability of CN-105 administration in patients with acute primary supratentorial ICH.

METHODS

Eligible patients were aged 30-80 years, had confirmed primary supratentorial ICH, and were able to intiate CN-105 administration (1.0 mg/kg every 6 h for 72 h) within 12 h of symptom onset. A priori defined safety end points, including hematoma volume, pharmacokinetics, and 30-day neurological outcomes, were analyzed. For clinical outcomes, CATCH participants were compared 1:1 with a closely matched contemporary ICH cohort through random selection. Hematoma volumes determined from computed tomography images on days 0, 1, 2, and 5 and ordinal modified Rankin Scale score at 30 days after ICH were compared.

RESULTS

In 38 participants enrolled across six study sites in the United States, adverse events occurred at an expected rate without increase in hematoma expansion or neurological deterioration. CN-105 treatment had an odds ratio (95% confidence interval) of 2.69 (1.31-5.51) for lower 30-day modified Rankin Scale score, after adjustment for ICH score, sex, and race/ethnicity, as compared with a matched contemporary cohort.

CONCLUSIONS

CN-105 administration represents an excellent translational candidate for treatment of acute ICH because of its safety, dosing feasibility, favorable pharmacokinetics, and possible improvement in neurological recovery.

Neuroprotective Therapies for Spontaneous Intracerebral Hemorrhage

Patients who survive the initial ictus of spontaneous intracerebral hemorrhage (ICH) remain vulnerable to subsequent injury of the perilesional parenchyma by molecular and cellular responses to the hematoma. Secondary brain injury after ICH, which contributes to long-term functional impairment and mortality, has emerged as an attractive therapeutic target. This review summarizes preclinical and clinical evidence for neuroprotective therapies targeting secondary injury pathways following ICH. A focus on therapies with pleiotropic antiinflammatory effects that target thrombin-mediated chemotaxis and inflammatory cell migration has led to studies investigating statins, anticholinergics, sphingosine-1-phosphate receptor modulators, peroxisome proliferator activated receptor gamma agonists, and magnesium. Attempts to modulate ICH-induced blood-brain barrier breakdown and perihematomal edema formation has prompted studies of nonsteroidal antiinflammatory agents, matrix metalloproteinase inhibitors, and complement inhibitors. Iron chelators, such as deferoxamine and albumin, have been used to reduce the free radical injury that ensues from erythrocyte lysis. Stem cell transplantation has been assessed for its potential to enhance subacute neurogenesis and functional recovery. Despite promising preclinical results of numerous agents, their outcomes have not yet translated into positive clinical trials in patients with ICH. Further studies are necessary to improve our understanding of the molecular events that promote damage and inflammation of the perihematomal parenchyma after ICH. Elucidating the temporal and pathophysiologic features of this secondary brain injury could enhance the clinical efficacy of neuroprotective therapies for ICH.

Cerebrovascular Risk Factors in Possible or Probable Cerebral Amyloid Angiopathy, Modifier or Bystander?

Goal: Cerebral amyloid angiopathy (CAA) is a frequent cause of atypical intracerebral hemorrhage (ICH) in the elderly. Stroke risk factors such as arterial hypertension (AHT), atrial fibrillation (AFib), diabetes mellitus (DM), and renal dysfunction (RD) are increasingly apparent in these patients. In this retrospective study, we analyzed the presence of these stroke risk factors in different initial CAA presentations comprising cerebral microbleeds (CMB), acute ischemic stroke (AIS), cortical superficial hemosiderosis (cSS), or lobar ICH (LICH) and evaluated their influence on the initial clinical presentation of patients with CAA.

Material and Methods: We identified patients with at least possible CAA defined by the modified Boston criteria admitted to the Department of Neurology or Neurosurgery from 2002 to 2018.

Findings: In the overall cohort of 209 patients, we analyzed the correlation between the number of stroke risk factors and the initial clinical presentation of patients with CAA and could show the high multimorbidity of the collective. There are large differences between the subgroups with different initial clinical presentations, e.g., patients with CMB as initial CAA presentation have the highest number of cerebrovascular risk factors and recurrent AIS, whereas AFib is more frequent in the Neurosurgery Department.

Conclusion: There is a distinct overlap between the subgroups of CAA manifestations and stroke risk factors that need to be verified in larger patient collectives. Since these comorbidities are likely to influence the clinical course of CAA, they represent possible targets for secondary prevention until specific treatment for CAA becomes available.

Recurrent Lobar Hemorrhages and Multiple Cortical Superficial Siderosis in a Patient of Alzheimer's Disease With Homozygous APOE ε2 Allele Presenting Hypobetalipoproteinemia and Pathological Findings of 18F-THK5351 Positron Emission Tomography: A Case Report

In Alzheimer's disease, the apolipoprotein E gene (APOE) ε2 allele is a protective genetic factor, whereas the APOE ε4 allele is a genetic risk factor. However, both the APOE ε2 and the APOE ε4 alleles are genetic risk factors for lobar intracerebral hemorrhage. The reasons for the high prevalence of lobar intracerebral hemorrhage and the low prevalence of Alzheimer's disease with the APOE ε2 allele remains unknown. Here, we describe the case of a 79-year-old Japanese female with Alzheimer's disease, homozygous for the APOE ε2 allele. This patient presented with recurrent lobar hemorrhages and multiple cortical superficial siderosis. The findings on the ¹¹C-labeled Pittsburgh Compound B-positron emission tomography (PET) were characteristic of Alzheimer's disease. ¹⁸F-THK5351 PET revealed that the accumulation of ¹⁸F-THK 5351 in the right pyramidal tract at the pontine level, the cerebral peduncle of the midbrain, and the internal capsule, reflecting the lesions of the previous lobar intracerebral hemorrhage in the right frontal lobe. Moreover, ¹⁸F-THK5351 accumulated in the bilateral globus pallidum, amygdala, caudate nuclei, and the substantia nigra of the midbrain, which were probably off-target reaction, by binding to monoamine oxidase B (MAO-B). ¹⁸F-THK5351 were also detected in the periphery of prior lobar hemorrhages and a cortical subarachnoid hemorrhage, as well as in some, but not all, areas affected by cortical siderosis. Besides, ¹⁸F-THK5351 retentions were observed in the bilateral medial temporal cortices and several cortical areas without cerebral amyloid angiopathy or prior hemorrhages, possibly where tau might accumulate. This is the first report of a patient with Alzheimer's disease, carrying homozygous APOE ε2 allele and presenting with recurrent lobar hemorrhages, multiple cortical superficial siderosis, and immunohistochemically vascular amyloid β. The ¹⁸F-THK5351 PET findings suggested MAO-B concentrated regions, astroglial activation, Waller degeneration of the pyramidal tract, neuroinflammation due to CAA related hemorrhages, and possible tau accumulation.

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 predicts subarachnoid extension in spontaneous intracerebral haemorrhage

BACKGROUND AND PURPOSE

Spontaneous intracerebral haemorrhage (ICH) with subarachnoid extension (SAHE) predicts poor outcomes and haematoma expansion in spontaneous ICH and is also a potential predictor of the severity of vascular amyloid deposition. The biological underpinnings of SAHE remain elusive. A study was conducted to identify risk factors associated with SAHE.

METHODS

A retrospective analysis was performed of an ongoing prospective cohort of primary spontaneous supratentorial ICH patients admitted to Tongji Hospital. SAHE was rated on baseline noncontrast computed tomography images by investigators blinded to the clinical data.

RESULTS

A total of 189 patients were enrolled. Apolipoprotein E (APOE) ε2 copies (p = 0.020), but not APOE ε4 copies (p > 0.2), were more common in patients with SAHE in univariate analysis. After controlling for confounding factors in multiple logistic regression, lobar haematoma (odds ratio [OR] 14.21, 95% confidence interval [CI] 5.89-34.33; p < 0.001), large haematoma volume (OR 1.04, 95% CI 1.02-1.06; p < 0.001) and APOE ε2 copies (OR 3.07, 95% CI 1.05-8.97; p = 0.041) were three independent predictors of SAHE. For subgroup analysis stratified by location, APOE ε2 showed a possible association with SAHE in lobar ICH (p = 0.026) but not in deep ICH (p > 0.2). No significant association was found between APOE ε4 copies and either lobar (p > 0.2) or deep ICH (p > 0.2).

CONCLUSIONS

The APOE ε2 allele predicts SAHE in spontaneous supratentorial ICH. The association may predominantly apply to lobar ICH. Given the established relationship between the APOE ε2 allele and pathological cerebrovascular changes, our findings suggest that SAHE involves genetically driven vessel pathology.

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.

Genetic underpinnings of cerebral edema in acute brain injury: an opportunity for pathway discovery

Cerebral edema constitutes an important contributor to secondary injury in acute brain injury. The quantification of cerebral edema in neuroimaging, a well-established biomarker of secondary brain injury, represents a useful intermediate phenotype to study edema formation. Population genetics provides powerful tools to identify novel susceptibility genes, biological pathways and therapeutic targets related to brain edema formation. Here, we provide an overview of the pathogenesis of cerebral edema, introduce relevant genetic methods to study this process, and discuss the ongoing research on the genetic underpinnings of edema formation in acute brain injury. The epsilon 2 and 4 variants within the Apolipoprotein E (APOE) gene are associated with worse outcome after traumatic brain injury and intracerebral hemorrhage, and recent studies link these polymorphisms to inflammatory processes that lead to blood-brain barrier disruption and vasogenic edema. For the Haptoglobin gene (HP), the Hp 2-2 genotype associates with worse outcome after acute brain injury, whereas the haptoglobin Hp 1-1 genotype correlates with increased edema in the early phases of intracerebral hemorrhage. Another important protein in cerebral edema is aquaporin 4, coded by the AQP4 gene. AQP4 mutations contribute to the formation of cytotoxic edema, and further genetic research is necessary to help elucidate the mediating mechanism. Findings supporting the target genes outlined above require replication in larger samples and evaluation in non-white populations. These next steps will be significantly facilitated by the rapid changes observed in the field of population genetics, including large international collaborations, open access to genetic data, and significant reductions in the cost of genotyping technologies.

Understanding the Pathophysiology of Cerebral Amyloid Angiopathy

Cerebral amyloid angiopathy (CAA), one of the main types of cerebral small vessel disease, is a major cause of spontaneous intracerebral haemorrhage and an important contributor to cognitive decline in elderly patients. Despite the number of experimental in vitro studies and animal models, the pathophysiology of CAA is still largely unknown. Although several pathogenic mechanisms including an unbalance between production and clearance of amyloid beta (Aβ) protein as well as ‘the prion hypothesis’ have been invoked as possible disease triggers, they do not explain completely the disease pathogenesis. This incomplete disease knowledge limits the implementation of treatments able to prevent or halt the clinical progression. The continuous increase of CAA patients makes imperative the development of suitable experimental in vitro or animal models to identify disease biomarkers and new pharmacological treatments that could be administered in the early disease stages to prevent irreversible changes and disease progression.

Multilevel omics for the discovery of biomarkers and therapeutic targets for stroke

Despite many years of research, no biomarkers for stroke are available to use in clinical practice. Progress in high-throughput technologies has provided new opportunities to understand the pathophysiology of this complex disease, and these studies have generated large amounts of data and information at different molecular levels. The integration of these multi-omics data means that thousands of proteins (proteomics), genes (genomics), RNAs (transcriptomics) and metabolites (metabolomics) can be studied simultaneously, revealing interaction networks between the molecular levels. Integrated analysis of multi-omics data will provide useful insight into stroke pathogenesis, identification of therapeutic targets and biomarker discovery. In this Review, we detail current knowledge on the pathology of stroke and the current status of biomarker research in stroke. We summarize how proteomics, metabolomics, transcriptomics and genomics are all contributing to the identification of new candidate biomarkers that could be developed and used in clinical stroke management.

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.

Genetic Variation and Response to Neurocritical Illness: a Powerful Approach to Identify Novel Pathophysiological Mechanisms and Therapeutic Targets

Disease-specific therapeutic options for critically ill neurological patients are limited. The identification of new preventive, therapeutic, and rehabilitation strategies is of the utmost importance in the field of neurocritical care research. Population genetics offers powerful tools to identify and prioritize biological pathways to be targeted by novel interventions. New treatments with supportive genetic evidence have twice the chances of obtaining final FDA approval compared to those without this support. Large collaborations, public access to data, reproducible science, and innovative analytical methods have exponentially increased the pace of discoveries related to neurocritical care genetics.

Incidence of Convexal Subarachnoid Hemorrhage in the Elderly: The Mayo Clinic Study of Aging

OBJECTIVES

Nontraumatic convexal subarachnoid hemorrhages in the elderly can be a manifestation of cerebral amyloid angiopathy associated with a high risk of future intracerebral hemorrhage. The incidence in the elderly population is unknown. Our objectives were to: 1) determine the incidence of convexal subarachnoid hemorrhage in a population-based study, and, 2) to compare apopolipoprotein-E genotype and amyloid positron emission tomographic (PET) imaging for those with versus without hemorrhage.

METHODS

Between 11/29/2004 and 3/11/2017, 4462 individuals without hemorrhage at baseline participated in the population-based Mayo Clinic Study of Aging. We used the Rochester Epidemiology Project medical records-linkage system to identify intracerebral hemorrhages. Records and images were reviewed to identify convexal subarachnoid hemorrhage. Neuroimaging characteristics, demographics, medications, and apopolipoprotein-E genotype were recorded.

RESULTS

Four cases were identified. The incidence of convexal subarachnoid hemorrhage was 14.1 per 100,000 person years. Three occurred in women, median age, 79 (range: 71-84). One patient had coexisting cerebral microbleeds. Two participants developed a subsequent lobar intracerebral hemorrhage at a median of 4.75 years after convexal subarachnoid hemorrhage. The apopolipoprotein-E -allele combinations of the 4 were: 3/3, 3/3, 2/2, and 2/3. On Pittsburgh Compound B-PET imaging, median standardized uptake value ratio with convexal subarachnoid hemorrhage was 1.86 (range: 1.38-2.34).

CONCLUSIONS

Convexal subarachnoid hemorrhage is rare in the older population, occurring with an incidence of about 14 per 100,000 person years. Yet, when present, it may be associated with a high risk of future intracerebral hemorrhage.

Cortical superficial siderosis and bleeding risk in cerebral amyloid angiopathy: A meta-analysis

OBJECTIVE

To assess the association of cortical superficial siderosis (cSS) presence and extent with future bleeding risk in cerebral amyloid angiopathy (CAA).

METHODS

This was a meta-analysis of clinical cohorts of symptomatic patients with CAA who had T2*-MRI at baseline and clinical follow-up for future intracerebral hemorrhage (ICH). We pooled data in a 2-stage meta-analysis using random effects models. Covariate-adjusted hazard ratios (adjHR) from multivariable Cox proportional hazard models were used.

RESULTS

We included data from 6 eligible studies (n = 1,239). cSS pooled prevalence was 34% (95% confidence interval [CI] 26%-41%; I ² 87.94%; p < 0.001): focal cSS prevalence was 14% (95% CI 12%-16%; I ² 6.75%; p = 0.37), and disseminated cSS prevalence was 20% (95% CI 13%-26%; I ² 90.39%; p < 0.001). During a mean follow-up of 3.1 years (range 1-4 years), 162/1,239 patients experienced a symptomatic ICH-pooled incidence rate 6.9% per year (95% CI 3.9%-9.8% per year; I ² 83%; p < 0.001). ICH incidence rates per year according to cSS status were 3.9% (95% CI 1.7%-6.1%; I ² 70%; p = 0.018) for patients without cSS, 11.1% (95% CI 7%-15.2%; I ² 56.8%; p = 0.074) for cSS presence, 9.1% (95% CI 5.5%-12.8%; I ² 0%; p = 0.994) for focal cSS, and 12.5% (95% CI 5.3%-19.7%; I ² 73.2%; p = 0.011) for disseminated cSS. In adjusted pooled analysis, any cSS presence was independently associated with increased future ICH risk (adjHR 2.14; 95% CI 1.19-3.85; p < 0.0001). Focal cSS was linked with ICH risk (adjHR 2.11; 95% CI 1.31-2.41; p = 0.002), while disseminated cSS conferred the strongest bleeding risk (adjHR 4.28; 95% CI 2.91-6.30; p < 0.0001).

CONCLUSION

In patients with CAA, cSS presence and extent are the most important MRI prognostic risk factors for future ICH, likely useful in treatment planning.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that in symptomatic CAA survivors with baseline T2*-MRI, cSS (particularly if disseminated, i.e., affecting >3 sulci) increases the risk of future ICH.

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.

Rapid Cognitive Decline and Recurrent Falls in a 71 Year-Old Man Due to Cerebral Amyloidangiopathy-Related Inflammation (CAA-RI)

Cognitive decline and falls in the elderly are common and are often accepted as natural and inevitable by relatives and health care professionals, but frequently there are specific and treatable diseases that should be revealed. In our case, cerebral amyloid angiopathy-related inflammation (CAA-RI) was causative for neuro-psychiatric symptoms and worsening of gait in a 71 year-old man with recurrent falls and decline of gait and cognition. Cerebral amyloidangiopathy (CAA) is an important cause of cerebrovascular disorders in the elderly, characterized by leukoencephalopathy combined with lobar or small cortical hemorrhage due to amyloid deposition in cortical and leptomeningeal vessels. In several conditions, amyloid deposition can provoke inflammation or edema that lead to -normally reversible- encephalopathy. CAA-RI is then characterized by subacute neurobehavioral symptoms, headache, seizures or stroke-like signs. The first therapeutic option after confirming the diagnosis is treatment with glucocorticoids. Despite treatment with prednisolone, our patient could not regain his unrestricted mobility and self-help competence. Our report aims to sharpen awareness for CAA and its inflammatory form (CAA-RI) in healthcare professionals involved in medical care of the elderly and provide a short summary of this disease.

Acute dizziness with potential life-threatening event: A case series from single ICU

BACKGROUND

Whether the acute dizziness would be associated with potentially life-threatening event, which was previously unknown.

METHODS

Between Jan 2014 and Dec 2016, We performed a retrospective survey to investigate the clinical data of patients with acute dizziness from an intensive care unit (ICU) in China. Inclusion criteria for all cases were presented with acute dizziness at onset, and then with a potentially life-threatening event. Baseline data and 30-days outcomes were collected.

RESULTS

Approximately 1.0% of ICU patients had an acute dizziness with potentially life-threatening events. The median age of patients was 60 years (range 23 to 81 years), male: female ratio was 1.8:1. The causes of acute dizziness included focal cerebral hemorrhage in 15 cases (60%), shock in 7cases (28%), and cerebral infarction in 3 cases (12%). The most frequent potentially life-threatening event was acute brain failure (24/25), and the most common cause leading to brain failure was the lesion enlarged (54.2%, including hematoma enlargement in 8 cases, large area infarction or new infarction in 3 cases, and intraventricular hemorrhage in 2 cases). The second potentially life-threatening event was septic shock/secondary sepsis (45.8%). The fatality rate for all life- threatening events was in 64%. Compared with the survival group, the patients with lesion enlarged (56.3% vs. 11.1%, p < 0.05), acute respiratory failure (93.8% vs. 55.6% p < 0.05), lactate level (5.3 mmol/l vs. 1.3 mmol/l, p < 0.05), and Sequential Organ Failure Assessment (SOFA) score (6.9 vs. 3.4, p < 0.0001) in the non-survival group were significantly higher, while late mean arterial blood pressure (84.6 mmHg vs.124 mmHg, p < 0.0001), GCS score (5.0 score vs. 15 score, p < 0.0001) in the non-survival group were significantly lower.

CONCLUSION

Acute dizziness with potentially life-threatening events accounts for about 1% of adult ICU patients. Acute dizziness in ICU patients is associated with a high risk of death within 30 days of onset.

APOE genotype, hypertension severity and outcomes after intracerebral haemorrhage

Intracerebral haemorrhage in the elderly is a severe manifestation of common forms of cerebral small vessel disease. Nearly 60% of intracerebral haemorrhage survivors will develop clinical manifestations of small vessel disease progression including recurrent haemorrhage, ischaemic stroke, dementia, late-life depression and gait impairment within 5 years. Blood pressure measurements following intracerebral haemorrhage are strongly associated with this risk. However, aggressive blood pressure lowering in the elderly carries substantial risks. In order to determine whether there might be an opportunity to select individuals at the highest risk for small vessel disease progression for aggressive blood pressure reduction, we investigated whether APOE gene variants ɛ2/ɛ4 modify the association between blood pressure and small vessel disease clinical progression after intracerebral haemorrhage. We conducted a single-centre longitudinal study at a tertiary care referral centre (Massachusetts General Hospital in Boston, MA, USA), analysing 716 consecutive survivors of acute intracerebral haemorrhage, enrolled from January 2006 to December 2016. We conducted research interviews at the time of enrolment and obtained APOE genotypes from peripheral venous blood samples. We followed patients longitudinally by means of validated phone-based research encounters, aimed at gathering measurements of systolic and diastolic blood pressure, as well as information on small vessel disease clinical outcomes (including recurrent haemorrhage, incident ischaemic stroke, incident dementia, incident depression and incident gait impairment). APOE ε4 and systolic blood pressure were associated with the risk of recurrent haemorrhage, ischaemic stroke and post-haemorrhage dementia, depression and gait impairment (all P < 0.05). APOE ε4 and systolic blood pressure interacted to increase the risk of recurrent haemorrhage, ischaemic stroke, dementia and gait impairment (all interaction P < 0.05). Among patients with elevated blood pressure following intracerebral haemorrhage (average systolic blood pressure 120–129 mmHg and diastolic blood pressure <80 mmHg) only those with one or more APOE ε4 copies were at increased risk for one or more small vessel disease outcomes (hazard ratio = 1.97, 95% confidence interval 1.17–3.31). Among haemorrhage survivors with hypertension (stage 1 and beyond) APOE genotype also stratified risk for all small vessel disease outcomes. In conclusion, APOE genotype modifies the already strong association of hypertension with multiple small vessel disease clinical outcomes among intracerebral haemorrhage survivors. These data raise the possibility that genetic screening could inform blood pressure treatment goals in this patient population.

Genetic underpinnings of recovery after stroke: an opportunity for gene discovery, risk stratification, and precision medicine

As the number of stroke survivors continues to increase, identification of therapeutic targets for stroke recovery has become a priority in stroke genomics research. The introduction of high-throughput genotyping technologies and novel analytical tools has significantly advanced our understanding of the genetic underpinnings of stroke recovery.

Invited Review: The spectrum of age-related small vessel diseases: potential overlap and interactions of amyloid and nonamyloid vasculopathies

Deep perforator arteriopathy (DPA) and cerebral amyloid angiopathy (CAA) are the commonest known cerebral small vessel diseases (CSVD), which cause ischaemic stroke, intracebral haemorrhage (ICH) and vascular cognitive impairment (VCI). While thus far mainly considered as separate entities, we here propose that DPA and CAA share similarities, overlap and interact, so that 'pure' DPA or CAA are extremes along a continuum of age-related small vessel pathologies. We suggest blood-brain barrier (BBB) breakdown, endothelial damage and impaired perivascular β-amyloid (Aβ) drainage are hallmark common mechanisms connecting DPA and CAA. We also suggest a need for new biomarkers (e.g. high-resolution imaging) to deepen understanding of the complex relationships between DPA and CAA.

Long-Term Follow-Up of Cerebral Amyloid Angiopathy-Associated Intracranial Hemorrhage Reveals a High Prevalence of Atrial Fibrillation

GOAL

Cerebral amyloid angiopathy (CAA) is the second-most common cause of nontraumatic intracerebral hemorrhages (ICH), surpassed only by uncontrolled hypertension. We characterized the percentage, risk factors, and comorbidities of patients suffering from CAA-related ICH in relation to long-term outcomes.

MATERIAL AND METHODS

We performed retrospective analyses and clinical follow-ups of individuals suffering from ICH who were directly admitted to neurosurgery between 2002 and 2016.

FINDINGS

Seventy-four of 174 (42%) spontaneous nontraumatic lobar ICH cases leastwise satisfied the modified Boston criteria definition for at least "possible CAA." Females suffered a higher risk of CAA-caused ICH (42 of 74, 56.8%, P= .035). Atrial fibrillation as a major comorbidity was observed in 19 patients (25.7%). Recovery (decrease of modified Rankin scale [mRS]) was highest during hospitalization in the acute clinic. One-year mortality was as follows: 14 of 25 patients (56%) with probable CAA without supporting pathology, 6 of 18, and 8 of 31 patients with supporting pathology and possible CAA, respectively. Only 10 of 74 (13.6%) had favorable long-term outcomes (mRS ≤2). Increasing numbers of lobar hemorrhages, low initial Glasgow Coma Scale, and subarachnoid hemorrhage were significantly associated with poor survivability, whereas statins, antithrombotic agents, an intraventricular hemorrhage, and midline shift played seemingly minor roles.

CONCLUSIONS

Symptomatic ICH is a serious stage in CAA progression with high mortality. The high incidence of concurrent atrial fibrillation in these patients may support data on more widespread vascular pathology in CAA.

Influences of genetic variants on stroke recovery: a meta-analysis of the 31,895 cases

Background

The influences of genetic variants on functional clinical outcomes following stroke are unclear. In order to reliably quantify these influences, we undertook a comprehensive meta-analysis of outcomes after acute intracerebral haemorrhage (ICH) or ischaemic stroke (AIS) in relation to different genetic variants.

Methods

PubMed, PsycInfo, Embase and Medline electronic databases were searched up to January 2019. Outcomes, defined as favourable or poor, were assessed by validated scales (Barthel index, modified Rankin scale, Glasgow outcome scale and National Institutes of Health stroke scale).

Results

Ninety-two publications comprising 31,895 cases met our inclusion criteria. Poor outcome was observed in patients with ICH who possessed the APOE4 allele: OR =2.60 (95% CI = 1.25–5.41, p = 0.01) and in AIS patients with the GA or AA variant at the BDNF-196 locus: OR = 2.60 (95% CI = 1.25–5.41, p = 0.01) or a loss of function allele of CYP2C19: OR = 2.36 (95% CI = 1.56–3.55, p < 0.0001). Poor outcome was not associated with APOE4: OR = 1.02 (95% CI = 0.81–1.27, p = 0.90) or IL6-174 G/C: OR = 2.21 (95% CI = 0.55–8.86, p = 0.26) in patients with AIS.

Conclusions

We demonstrate that recovery of AIS was unfavourably associated with variants of BDNF and CYP2C19 genes whilst recovery of ICH was unfavourably associated with APOE4 gene.

Electronic supplementary material

The online version of this article (10.1007/s10072-019-04024-w) contains supplementary material, which is available to authorized users.