Effects of apolipoprotein E genotype on outcome after ischaemic stroke, intracerebral haemorrhage and subarachnoid haemorrhage

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.

Apolipoprotein E ε4 Polymorphism as a Risk Factor for Ischemic Stroke: A Systematic Review and Meta-Analysis

Introduction

Rising studies indicate that the apolipoprotein E (APOE) gene is related to the susceptibility of ischemic stroke (IS). However, certain consensus is limited by the lack of a large sample size of researches. This meta-analysis was performed to explore the potential association between the APOE gene and IS.

Methods

To identify relevant case control studies in English publications by October 2020, we searched PubMed, Embase, Web of Science, and the Cochrane Library. Pooled odds ratios (ORs) with fixed- or random-effect models and corresponding 95% confidence intervals (CIs) were calculated to analyze potential associations.

Results

A total of 55 researches from 32 countries containing 12207 IS cases and 27742 controls were included. The association between APOE gene ε4 mutation and IS was confirmed (ε4 vs. ε3 allele: pooled OR = 1.374, 95% CI, 1.214-1.556; ε2/ε4 vs. ε3/ε3: pooled OR = 1.233, 95% CI, 1.056-1.440; ε3/ε4 vs. ε3/ε3: pooled OR = 1.340, 95% CI, 1.165-1.542; ε4/ε4 vs. ε3/ε3: pooled OR = 1.833, 95% CI, 1.542-2.179; and APOE ε4 carriers vs. non-ε4 carriers: pooled OR = 1.377; 95% CI, 1.203-1.576). Interestingly, APOE ε4 mutation showed a dose-response correlation with IS risk (ε4/ε4 vs. ε2/ε4: pooled OR = 1.625; 95% CI, 1.281-2.060; ε4/ε4 vs. ε3/ε4: pooled OR = 1.301; 95% CI, 1.077-1.571). Similar conclusions were drawn in the small artery disease (SAD) subtype, but not in large artery atherosclerosis (LAA) or in cardioaortic embolism (CE), by subgroup analysis.

Conclusions

These observations reveal that specific APOE ε4 mutation was significantly associated with the risk of IS in a dose-dependent manner, while APOE ε4 mutation was related to SAD subtype onset without a cumulative effect.

Global research trends of Apolipoprotein E in central nervous system: A scientometric analysis

Apolipoprotein E (apoE, protein; APOE, gene) involves in cholesterol recycling and redistribution by mediating lipoprotein pathways unique to central nervous system (CNS), which is a potential therapeutic target for diseases. We visually analyzed the research hotspots of APOE related to CNS in this work, by scientometric analysis from the Web of Science Core Collection (WOSCC) database over the past two decades. A total of 25,719 references of "APOE" and 836 references of "APOE in CNS" were retrieved from the WOSCC on October 26, 2020, and then VOSviewer 1.6.15, Citespace 5.7.R2 were used for visual analysis. Over the last two decades, the research on the field of APOE in CNS is not faddish. Although many funds, organizations, and scholars were affiliated in this field, organizations and scholars, especially the top teams in this field, still lacked close cooperation with other teams around the world. Few articles with high citations had been published in the last decade, but recent studies still lacked scale and breakthrough, and the keywords associated with APOE appeared more outdated. However, the current researches have not fully elucidated the crosstalk between APOE and neuroinflammation in CNS, some new ideas may rekindle the research enthusiasm of scholars. Although the field of APOE in CNS appeared more outdated. Based on keyword analysis, we hypothesized new ideas for further investigation of neuroinflammation would light the interest of APOE in CNS for the scholars. The crosstalk between ApoE and inflammasome may be the focus of future researches. How APOE modulates the time course or intensity of the inflammasome activation, inflammatory response (proinflammatory or anti-inflammatory), and pathological process of CNS disease deserves future attention in both basic and clinical studies. More apoE/APOE-targeted pharmacological interventions will be available for preclinical experiments and clinical trials and bring hope for patients with CNS diseases.

Sex differences in the association between the APOEε4 allele and hearing impairment: A longitudinal memory clinic study

BACKGROUND

The APOEε4 allele and hearing impairment are risk factors for dementia. Cross-sectional studies have shown controversial findings regarding the relationship between APOEε4 and hearing impairment. These may be explained by reported sex differences in the association between APOEε4 and some Alzheimer's disease biomarkers. We aimed to investigate APOEε4 and hearing impairment in a longitudinal setting considering the modifying effects of sex on APOEε4.

METHODS

In total, 1810 subjects with APOE genotype at Ilsan Hospital memory clinics were linked to the longitudinal National Health Insurance Service database with International Statistical Classification of Diseases and Related Health Problems 10th revision (ICD-10) diagnosis codes of hearing impairment. After excluding cases with prevalent hearing impairment and incomplete records, 1092 subjects were analyzed for the period January 2004-July 2019. We used Cox proportional hazard models with or without adjustment for education, hypertension, diabetes, and cognitive function. Effect modification was analyzed by sex stratification and by adding APOEε4 by sex interaction terms.

RESULTS

Hearing impairment did not differ between APOEε4 carriers and non-carriers. Sex-stratification analysis with an unadjusted model showed men with APOEε4 developed more hearing impairment than men without (HR 1.90, 95% CI 1.20-3.01), but women did not. The results remained similar in covariate-adjusted models. The interaction between APOEε4 and sex was also significant regardless of adjustment.

CONCLUSIONS

Our longitudinal analyses suggested male memory clinic visitors with APOEε4 allele were more likely to develop hearing impairment than those without the genotype. This group may benefit more from regular monitoring and preventive measures for hearing impairment.

Apolipoprotein E ε4 and cognitive function after surgery in middle-aged and elderly Danish twins

BACKGROUND

Transient cognitive impairment is common in adult patients of all ages following anaesthesia and surgery. Apolipoprotein E (APOE) ε4 carriers may have a larger deterioration in short-term cognitive function after major surgery compared with APOE ε4 noncarriers.

OBJECTIVES

The aim was to examine the effect of APOE ε4 on the association between exposure to surgery and anaesthesia, and subsequent cognitive functioning. A more pronounced deterioration in cognitive function in APOE ε4 carriers was hypothesised.

DESIGN

An observational cross-sectional and a 6 to 10 years longitudinal twin cohort design.

SETTING

Survey and register study of 2936 Danish twins aged 45 to 92 years.

MAIN OUTCOME MEASURES

Cognitive function was assessed using five age-sensitive cognitive tests. In the cross-sectional study, we compared twins exposed to surgery with a reference group (unexposed). Linear regression models were used adjusting for sex and age and stratified by APOE ε4 carrier status. In the longitudinal cognitive follow-up study 1671 twins participated. Intrapair analyses were also performed using 70 same-sexed twin pairs concordant for APOE ε4 carrier status, but discordant for major surgery.

RESULTS

APOE ε4 carriers had lower cognitive scores compared with noncarriers, and this was statistically significant in elderly twins 70+ years of age (mean difference, -0.67; 95% CI, -1.14 to -0.17). There was no significant impact on cognitive function after surgery according to APOE ε4 carrier status in the cross-sectional study. Similarly, there was no APOE ε4 modification in the longitudinal study. Also, in the intrapair analyses no evidence was found of lower cognitive score after major surgery compared with the nonexposed cotwins among APOE ε4 carriers.

CONCLUSION

No evidence was found of more pronounced long-term deterioration in cognitive function after surgery among APOE ε4 carriers, but elderly APOE ε4 carriers in general performed worse on the cognitive tests than noncarriers.

APOE4 Copy Number-Dependent Proteomic Changes in the Cerebrospinal Fluid

Background:

APOE4 has been hypothesized to increase Alzheimer’s disease risk by increasing neuroinflammation, though the specific neuroinflammatory pathways involved are unclear.

Objective:

Characterize cerebrospinal fluid (CSF) proteomic changes related to APOE4 copy number.

Methods:

We analyzed targeted proteomic data from ADNI CSF samples using a linear regression model adjusting for age, sex, and APOE4 copy number, and additional linear models also adjusting for AD clinical status or for CSF Aβ, tau, or p-tau levels. False discovery rate was used to correct for multiple comparisons correction.

Results:

Increasing APOE4 copy number was associated with a significant decrease in a CRP peptide level across all five models (q < 0.05 for each), and with significant increases in ALDOA, CH3L1 (YKL-40), and FABPH peptide levels (q < 0.05 for each) except when controlling for AD clinical status or neurodegeneration biomarkers (i.e., CSF tau or p-tau). In all models except the one controlling for CSF Aβ levels, though not statistically significant, there was a consistent inverse direction of association between APOE4 copy number and the levels of all 24 peptides from all 8 different complement proteins measured. The odds of this happening by chance for 24 unrelated peptides would be less than 1 in 16 million.

Conclusion:

Increasing APOE4 copy number was associated with decreased CSF CRP levels across all models, and increased CSF ALDOA, CH3L1, and FABH levels when controlling for CSF Aβ levels. Increased APOE4 copy number may also be associated with decreased CSF complement pathway protein levels, a hypothesis for investigation in future studies.

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.

Factors affecting post-stroke motor recovery: Implications on neurotherapy after brain injury

Neurological disorders are a major cause of chronic disability globally among which stroke is a leading cause of chronic disability. The advances in the medical management of stroke patients over the past decade have significantly reduced mortality, but at the same time increased numbers of disabled survivors. Unfortunately, this reduction in mortality was not paralleled by satisfactory therapeutics and rehabilitation strategies that can improve functional recovery of patients. Motor recovery after brain injury is a complex, dynamic, and multifactorial process in which an interplay among genetic, pathophysiologic, sociodemographic and therapeutic factors determines the overall recovery trajectory. Although stroke recovery is the most well-studied form of post-injury neuronal recovery, a thorough understanding of the pathophysiology and determinants affecting stroke recovery is still lacking. Understanding the different variables affecting brain recovery after stroke will not only provide an opportunity to develop therapeutic interventions but also allow for developing personalized platforms for patient stratification and prognosis. We aim to provide a narrative review of major determinants for post-stroke recovery and their implications in other forms of brain injury.

Genetics and Genomics of Acute Neurologic Disorders

Neurologic diseases and injuries are complex and multifactorial, making risk prediction, targeted treatment modalities, and outcome prognostication difficult and elusive. Genetics and genomics have affected clinical practice in many aspects in medicine, particularly cancer treatment. Advancements in knowledge of genetic and genomic variability in neurologic disease and injury are growing rapidly. Although these data are not yet ready for use in clinical practice, research continues to progress and elucidate information that eventually will provide answers to complex neurologic questions and serve as a platform to provide individualized care plans aimed at improving outcomes. This article provides a focused review of relevant literature on genetics, genomics, and common complex neurologic disease and injury likely to be seen in the acute care setting.

Downregulation of Apolipoprotein-E and Apolipoprotein-J in Moyamoya Disease-A Proteome Analysis of Cerebrospinal Fluid

BACKGROUND AND PURPOSE

Genetic factors are closely involved in the etiology of moyamoya disease (MMD). However, its postgenomic mechanisms are still unknown. This study was aimed to identify specific biomarkers in the cerebrospinal fluid (CSF) of patients with MMD, using quantitative proteome technique.

METHODS

This study included 10 patients with MMD and 4 controls. The CSF was collected without blood contamination during surgery. A comparative 2-dimensional gel electrophoresis study (2D-PAGE) was performed. Protein spots that showed significant differences between moyamoya patients and controls were selected for further analysis by mass spectrometry.

RESULTS

On 2D-PAGE, 2 proteins were significantly upregulated, and 2 other proteins were downregulated in the CSF of MMD. Further mass spectrometry analysis revealed that haptoglobin and α-1-B-glycoprotein (A1BG) were upregulated. On the other hand, apolipoprotein-E (apoE), apoE precursor, and apolipoprotein-J (apoJ) were significantly downregulated in the CSF of MMD. The observed probability-based MOWSE score was 72 for haptoglobin (P <.05), 521 for A1BG (P <.05), 62 for apoE (P <.05), 72 for apoE precursor (P <.05), and 112 for apoJ (P <.05).

CONCLUSION

Although the role of A1BG in the central nervous system is still unknown, the overexpressed haptoglobin may indicate the inflammation and/or angiogenesis in MMD. The downregulation of apoE and apoJ strongly suggests a critical role of lipid metabolism in the development and progression of MMD. These proteins may be novel biomarkers in shedding light on the pathogenesis of MMD, although further studies would be warranted.

Apolipoprotein E mimetic peptide, CN-105, improves outcomes in ischemic stroke

Objective

At present, the absence of a pharmacological neuroprotectant represents an important unmet clinical need in the treatment of ischemic and traumatic brain injury. Recent evidence suggests that administration of apolipoprotein E mimetic therapies represent a viable therapeutic strategy in this setting. We investigate the neuroprotective and anti‐inflammatory properties of the apolipoprotein E mimetic pentapeptide, CN‐105, in a microglial cell line and murine model of ischemic stroke.

Methods

Ten to 13‐week‐old male C57/BL6 mice underwent transient middle cerebral artery occlusion and were randomly selected to receive CN‐105 (0.1 mg/kg) in 100 μL volume or vehicle via tail vein injection at various time points. Survival, motor‐sensory functional outcomes using rotarod test and 4‐limb wire hanging test, infarct volume assessment using 2,3,5‐Triphenyltetrazolium chloride staining method, and microglial activation in the contralateral hippocampus using F4/80 immunostaining were assessed at various time points. In vitro assessment of tumor necrosis factor‐alpha secretion in a microglial cell line was performed, and phosphoproteomic analysis conducted to explore early mechanistic pathways of CN‐105 in ischemic stroke.

Results

Mice receiving CN‐105 demonstrated improved survival, improved functional outcomes, reduced infarct volume, and reduced microglial activation. CN‐105 also suppressed inflammatory cytokines secretion in microglial cells in vitro. Phosphoproteomic signals suggest that CN‐105 reduces proinflammatory pathways and lower oxidative stress.

Interpretation

CN‐105 improves functional and histological outcomes in a murine model of ischemic stroke via modulation of neuroinflammatory pathways. Recent clinical trial of this compound has demonstrated favorable pharmacokinetic and safety profile, suggesting that CN‐105 represents an attractive candidate for clinical translation.

Polymorphisms of apolipoprotein E and aneurysmal subarachnoid haemorrhage: A meta-analysis

Subarachnoid haemorrhage (SAH) is characterised by bleeding in the subarachnoid space in the brain. There are various polymorphisms in genes which are associated with this disease. We performed a systematic meta- analysis to investigate the relationship of APOE polymorphism on aSAH. A comprehensive literature search was done in the Pubmed database, Science Direct, Cochrane library and Google Scholar. The OR and 95% CI were evaluated for the gene and aSAH association using fixed and random effect models. Publication bias was assessed using Begg's funnel plot and Egger's regression test. All statistical evaluations were done using the software Review Manager 5.0 and Comprehensive Meta Analysis v2.2.023. A total of 9 studies were assessed on APOE polymorphism (1100 Cases, 2732 Control). Meta analysis results showed significant association in ε2/ ε2 versus ε3/ε3, ε2 versus ε3 genetic models and ε2 allele frequency. In subgroup analysis statistically significant association was observed in Asians in the genetic models ε2/ ε2 versus ε3/ε3, ε2/ε3 versus ε3/ε3, ε2 versus ε3 and also in ε2 allele frequency. However, in Caucasian population only ε2/ε2 versus ε3/ε3 genetic model showed significant association between APOE and risk of aSAH. In this meta-analysis study, the ε2/ε2 genotype is associated with increased risk of aSAH.

BDNF Genotype Interacts with Motor Function to Influence Rehabilitation Responsiveness Poststroke

BACKGROUND

Persistent motor impairment is common but highly heterogeneous poststroke. Genetic polymorphisms, including those identified on the brain-derived neurotrophic factor (BDNF) and apolipoprotein E (APOE) genes, may contribute to this variability by limiting the capacity for use-dependent neuroplasticity, and hence rehabilitation responsiveness.

OBJECTIVE

To determine whether BDNF and APOE genotypes influence motor improvement facilitated by poststroke upper-limb rehabilitation.

METHODS

BDNF-Val66Met and APOE isoform genotypes were determined using leukocyte DNA for 55 community-dwelling patients 2-123 months poststroke. All patients completed a dose-matched upper-limb rehabilitation program of either Wii-based Movement Therapy or Constraint-induced Movement Therapy. Upper-limb motor function was assessed pre- and post-therapy using a suite of functional measures.

RESULTS

Motor function improved for all patients post-therapy, with no difference between therapy groups. In the pooled data, there was no significant effect of BDNF or APOE genotype on motor function at baseline, or following the intervention. However, a significant interaction between the level of residual motor function and BDNF genotype was identified (p = 0.029), whereby post-therapy improvement was significantly less for Met allele carriers with moderate and high, but not low motor function. There was no significant association between APOE genotype and therapy outcomes.

CONCLUSION

This study identified a novel interaction between the BDNF-Val66Met polymorphism, motor-function status, and the magnitude of improvement with rehabilitation in chronic stroke. This polymorphism does not preclude, but may reduce, the magnitude of motor improvement with therapy, particularly for patients with higher, but not lower residual motor function. BDNF genotype should be considered in the design and interpretation of clinical trials.

Understanding the cause of sporadic Alzheimer's disease

The increasing prevalence of Alzheimer's disease (AD) and a lack of effective prevention or disease-modifying therapies are global challenges with devastating personal, social and economic consequences. The amyloid β (Aβ) hypothesis posits that cerebral β-amyloidosis is a critical early event in AD pathogenesis. However, failed clinical trials of Aβ-centric drug candidates have called this hypothesis into question. Whereas we acknowledge that the Aβ hypothesis is far from disproven, we here re-visit the links between Aβ, tau and neurodegeneration. We review the genetics, epidemiology and pathology of sporadic AD and give an updated account of what is currently known about the molecular pathogenesis of the disease.

Genetic variation at the BDNF locus: evidence for association with long-term outcome after ischemic stroke

Background and Purpose

Rates and extent of recovery after stroke vary considerably between individuals and genetic factors are thought to contribute to post-stroke outcome. Brain-derived neurotrophic factor (BDNF) plays important roles in brain plasticity and repair and has been shown to be involved in stroke severity, recovery, and outcome in animal models. Few clinical studies on BDNF genotypes in relation to ischemic stroke have been performed. The aims of the present study are therefore to investigate whether genetic variation at the BDNF locus is associated with initial stroke severity, recovery and/or short-term and long-term functional outcome after ischemic stroke.

Methods

Four BDNF tagSNPs were analyzed in the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS; 600 patients and 600 controls, all aged 18–70 years). Stroke severity was assessed using the NIH Stroke Scale (NIHSS). Stroke recovery was defined as the change in NIHSS over a 3-month period. Short- and long-term functional outcome post-stroke was assessed using the modified Rankin Scale at 3 months and at 2 and 7 years after stroke, respectively.

Results

No SNP was associated with stroke severity or recovery at 3 months and no SNP had an impact on short-term outcome. However, rs11030119 was independently associated with poor functional outcome 7-years after stroke (OR 0.66, 95% CI 0.46–0.92; P =  0.006).

Conclusions

BDNF gene variants were not major contributors to ischemic stroke severity, recovery, or short-term functional outcome. However, this study suggests that variants in the BDNF gene may contribute to poor long-term functional outcome after ischemic stroke.

Does an Alzheimer's disease susceptibility gene influence the cognitive effects of cancer therapy?

The apolipoprotein E (APOE) e4 allele is the most prevalent genetic risk factor for Alzheimer's disease (AD). APOE e4 carriers suffer greater morbidity from head trauma, stroke, and carbon monoxide poisoning, yet possible interactions between APOE genotype and cancer therapy on cognition are unclear. Neuropathological and biomarker studies of young asymptomatic APOE e4 carriers that show elevated neocortical amyloid and medial temporal neurofibrillary tangles and longitudinal neuropsychological studies that show accelerated memory decline beginning around age 55-60 years define preclinical AD and have set the stage for assessing the potential adverse cognitive effects of cancer therapy in APOE e4 carriers.

The potential applications of Apolipoprotein E in personalized medicine

Personalized medicine uses various individual characteristics to guide medical decisions. Apolipoprotein (ApoE), the most studied polymorphism in humans, has been associated with several diseases. The purpose of this review is to elucidate the potential role of ApoE polymorphisms in personalized medicine, with a specific focus on neurodegenerative diseases, by giving an overview of its influence on disease risk assessment, diagnosis, prognosis, and therapy. This review is not a systematic inventory of the literature, but rather a summary and discussion of novel, influential and promising works in the field of ApoE research that could be valuable for personalized medicine. Empirical evidence suggests that ApoE genotype informs pre-symptomatic risk for a wide variety of diseases, is valuable for the diagnosis of type III dysbetalipoproteinemia, increases risk of dementia in neurodegenerative diseases, and is associated with a poor prognosis following acute brain damage. ApoE status appears to influence the efficacy of certain drugs, outcome of clinical trials, and might also give insight into disease prevention. Assessing ApoE genotype might therefore help to guide medical decisions in clinical practice.

Effects of APOE ε4 on brain amyloid, lacunar infarcts, and white matter lesions: a study among patients with subcortical vascular cognitive impairment

The relationship between the apolipoprotein E ε4 allele (APOE4) and factors associated with vascular cognitive impairment (VCI) is unclear. We aimed to examine the effects of APOE4 on brain amyloid beta using Pittsburg compound B (PiB) and subcortical cerebrovascular disease, as assessed by lacunes and white matter hyperintensities (WMH) in subcortical VCI (SVCI) patients. We recruited 230 subjects with normal cognition, 111 subjects with cognitive impairment due to clinically defined Alzheimer's disease (ADCI), and 134 subjects with clinically defined SVCI. A PiB retention ratio greater than 1.5 was considered to be PiB positive. Logistic regression analysis was performed to investigate whether APOE4 increased the risk for each cognitive impairment group. Multiple linear regression analysis was performed to investigate whether APOE4 was associated with brain amyloid beta, lacunes, and WMH. APOE4 did not increase the risk of PiB(-) SVCI (odds ratio [OR], 1.50; 95% confidence interval [CI], 0.79-2.84), whereas APOE4 increased the risk of PiB(+) SVCI (OR, 4.52; 95% CI, 1.70-11.97) and PiB(+) ADCI (odds ratio, 4.84; 95% CI, 2.54-7.91). In SVCI patients, APOE4 was positively associated with PiB retention ratio, whereas APOE4 was not associated with the number of lacunes or with WMH volume. Our results suggest that amyloid beta burden can occur in patients with and without subcortical cerebrovascular disease, and that it is associated with APOE4. However APOE4 might be independent of subcortical cerebrovascular disease.

Genetic risk factors for perinatal arterial ischemic stroke

The cause of perinatal arterial ischemic stroke is unknown in most cases. We explored whether genetic polymorphisms modify the risk of perinatal arterial ischemic stroke. In a population-based case-control study of 1997-2002 births at Kaiser Permanente Northern California, we identified 13 white infants with perinatal arterial ischemic stroke. Control subjects included 86 randomly selected white infants. We genotyped polymorphisms in nine genes involved in inflammation, thrombosis, or lipid metabolism previously linked with stroke, and compared genotype frequencies in case and control individuals. We tested several polymorphisms: tumor necrosis factor-α -308, interleukin-6, lymphotoxin A, factor V Leiden, methyltetrahydrofolate reductase 1298 and 667, prothrombin 20210, and apolipoprotein E ε2 and ε4 alleles. Patients with perinatal arterial ischemic stroke were more likely than control subjects to demonstrate at least one apolipoprotein E ε4 allele (54% vs 25%, P = 0.03). More patients with perinatal arterial ischemic stroke carried two ε4 alleles than did control subjects (15% vs 2%, P = 0.09), although this finding lacked statistical significance. Proinflammatory and prothrombotic polymorphisms were not associated with perinatal arterial ischemic stroke. The apolipoprotein E polymorphism may confer genetic susceptibility for perinatal arterial ischemic stroke. Larger population-based studies are required to confirm this finding.

Gene dose of apolipoprotein E and age-related hearing loss

Next to outer hair cell dysfunction, age-related hearing loss may be explained by apolipoprotein E (APOE) genotype. In the Leiden 85-plus Study, a population-based study, the participants were 85 years old. We measured hearing loss by pure-tone audiometry in 435 participants in relation to APOE. Results demonstrated that those with the APOE-ε4/ε4 genotype had the highest levels of hearing loss (n = 6; 56.1 dB), those with the APOE-ε3/ε4 or ε2/ε4 genotype (n = 89) had intermediate levels of hearing loss (51.0 dB), and those without the APOE-ε4 allele (n = 340) had the lowest levels of hearing loss (48.9 dB), p for trend = 0.02. Eighty percent of participants had hearing loss of 35 dB and more, that is, hearing impairment. The APOE-ε4 allele was associated with a 2.0-fold increased risk of hearing impairment (confidence interval [CI 95%], 1.0-4.0), compared with those without the APOE-ε4 allele. The risk for hearing impairment in subjects with the APOE-ε4 allele remained similar after adjustment for cardiovascular disease, stroke, and cognitive impairment. Our results suggest that the APOE-ε4 allele contributes to age-related hearing loss.

Neurocognitive correlates of nocturnal oxygen desaturation in a memory clinic population

Previous studies suggested that sleep apnea is associated with neurocognitive impairments but did not examine populations most likely to have clinically relevant impairments. Cross-sectional, retrospective analyses were performed on 108 patients (65 with mild cognitive impairment, 43 with dementia) seen in an academic medical center. Results indicated that severity of oxygen desaturation was associated with cognitive impairments in attention and executive function domains, even after controlling for age, sex, education, and depressive symptoms. Strength of associations was influenced by cardiovascular disease. Screening for nocturnal oxygen desaturation may be a useful procedure to assess for a potentially reversible cause of cognitive impairment.

Interaction between vascular factors and the APOE ε4 allele in predicting rate of progression in Alzheimer's disease

Vascular factors have been shown to affect the rate of Alzheimer's disease (AD) progression. However, the effect of the APOE ε4 allele on rate of progression has been ambiguous. Little research to date has examined an interaction between vascular factors and the APOE ε4 allele in predicting decline among AD patients. 216 participants with incident AD from a population of elderly persons in Cache County, Utah, were followed for a mean of 3.3 years and 4.2 follow-up visits. A history of vascular risk factors and conditions and anti-hypertensive use was assessed at the diagnostic visit. Linear mixed effects models tested interactions between the vascular factors, APOE ε4, and time as predictors of clinical progression on the Mini-Mental State Exam (MMSE) and Clinical Dementia Rating-Sum of Boxes (CDR-SB). Multiple comparisons were corrected using the Holm-Bonferroni method. There was a 3-way interaction between stroke, APOE ε4 and time in predicting MMSE decline (LR χ² = 10.32, 2 df, p = 0.006). For the CDR-SB, there were 3-way interactions between the APOE ε4, time and either myocardial infarction (LR χ² = 17.83, 2 df, p = 0.0001) or stroke (LR χ² = 11.48, 2 df, p = 0.003. Results suggest a complex relationship between the APOE ε4 and vascular factors in predicting cognitive and functional progression. Among individuals with a history of stroke or myocardial infarction at baseline, progression of AD is influenced by APOE ε4 carrier status and varies by time after AD diagnosis.

Correlation between genetic polymorphisms and stroke recovery: analysis of the GAIN Americas and GAIN International Studies

BACKGROUND AND PURPOSE

Recovery after stroke occurs on the basis of specific molecular events. Genetic polymorphisms associated with impaired neural repair or plasticity might reduce recovery from stroke and might also account for some of the intersubject variability in stroke recovery. This study hypothesized that the ApoE ε4 polymorphism and the val(66) met polymorphism for brain-derived neurotrophic factor (BDNF) are each associated with poorer outcome after stroke. Associations with mitochondrial genotype were also explored.

METHODS

Genotypes were determined in 255 stroke patients who also received behavioral evaluations in the Glycine Antagonist In Neuroprotection (GAIN) clinical trials. The primary outcome measure was recovery during the first month post-stroke, as this is the time when neural repair is at a maximum and so when genetic influences might have their largest impact. Two secondary outcome measures at 3 months post-stroke were also examined.

RESULTS

  Genotype groups were similar acutely post-stroke. Presence of the ApoE ε4 polymorphism was associated with significantly poorer recovery over the first month post-stroke (P = 0.023) and with a lower proportion of subjects with minimal or no disability (modified Rankin score 0-1, P = 0.01) at 3 months post-stroke. Indeed, those with this polymorphism were approximately half as likely to achieve minimal or no disability (18.2%) versus those with polymorphism absent (35.5%). Findings were confirmed in multivariate models. Results suggested possible effects from the val(66) met BDNF polymorphism and from the R0 mitochondrial DNA haplotype.

CONCLUSIONS

  Genetic factors, particularly the ApoE ε4 polymorphism, might contribute to variability in outcomes after stroke.

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

BACKGROUND

Carriers of APOE ε2 and ε4 have an increased risk of intracerebral haemorrhage (ICH) in lobar regions, presumably because of the effects of these gene variants on risk of cerebral amyloid angiopathy. We aimed to assess whether these variants also associate with severity of ICH, in terms of haematoma volume at presentation and subsequent outcome.

METHODS

We investigated the association of APOE ε2 and ε4 with ICH volume and outcomes in patients with primary ICH in three phases: a discovery phase of 865 individuals of European ancestry from the Genetics of Cerebral Hemorrhage on Anticoagulation study, and replication phases of 946 Europeans (replication 1) and 214 African-Americans (replication 2) from an additional six studies. We also assessed the association of APOE variants with ICH volume and outcomes in meta-analyses of results from all three phases, and the association of APOE ε4 with mortality in a further meta-analysis including data from previous reports. Admission ICH volume was quantified on CT scan. We assessed functional outcome (modified Rankin scale score 3-6) and mortality at 90 days. We used linear regression to establish the effect of genotype on haematoma volume and logistic regression to assess the effect on outcome from ICH.

FINDINGS

For patients with lobar ICH, carriers of the APOE ε2 allele had larger ICH volumes than did non-carriers in the discovery phase (p=2·5×10(-5)), in both replication phases (p=0·008 in Europeans and p=0·016 in African-Americans), and in the meta-analysis (p=3·2×10(-8)). In the meta-analysis, each copy of APOE ε2 increased haematoma size by a mean of 5·3 mL (95% CI 4·7-5·9; p=0·004). Carriers of APOE ε2 had increased mortality (odds ratio [OR] 1·50, 95% CI 1·23-1·82; p=2·45×10(-5)) and poorer functional outcomes (modified Rankin scale score 3-6; 1·52, 1·25-1·85; p=1·74×10(-5)) compared with non-carriers after lobar ICH. APOE ε4 was not associated with lobar ICH volume, functional outcome, or mortality in the discovery phase, replication phases, or meta-analysis of these three phases; in our further meta-analysis of 2194 patients, this variant did not increase risk of mortality (1·08, 0·86-1·36; p=0·52). APOE allele variants were not associated with deep ICH volume, functional outcome, or mortality.

INTERPRETATION

Vasculopathic changes associated with the APOE ε2 allele might have a role in the severity and clinical course of lobar ICH. Screening of patients who have ICH to identify the ε2 variant might allow identification of those at increased risk of mortality and poor functional outcomes.

FUNDING

US National Institutes of Health-National Institute of Neurological Disorders and Stroke, Keane Stroke Genetics Research Fund, Edward and Maybeth Sonn Research Fund, and US National Center for Research Resources.

Apolipoprotein E in Alzheimer's disease and other neurological disorders

Apolipoprotein E (APOE) is a 299-aminoacid protein encoded by the APOE gene. Three common polymorphisms in the APOE gene, ɛ2, ɛ3, and ɛ4, result in a single aminoacid change in the APOE protein. APOE ɛ2, ɛ3, and ɛ4 alleles strongly alter, in a dose-dependent manner, the likelihood of developing Alzheimer's disease and cerebral amyloid angiopathy. In particular, APOE ɛ4 is associated with increased risk for Alzheimer's disease whereas APOE ɛ2 is associated with decreased risk. The effects of APOE genotype on risk of these diseases are likely to be mediated by differential effects of APOE on amyloid-β accumulation in the brain and its vasculature. Response to treatment for Alzheimer's disease might differ according to APOE genotype. Because convincing evidence ties the APOE genotype to risk of Alzheimer's disease and cerebral amyloid angiopathy, APOE has been studied in other neurological diseases. APOE ɛ4 is associated with poor outcome after traumatic brain injury and brain haemorrhage, although the mechanisms underlying these associations are unclear. The possibility that APOE has a role in these and other neurological diseases has been of great interest, but convincing associations have not yet emerged.

Genetic influences on neural plasticity

Neural plasticity refers to the capability of the brain to alter function or structure in response to a range of events and is a crucial component of both functional recovery after injury and skill learning in healthy individuals. A number of factors influence neural plasticity and recovery of function after brain injury. The current review considers the impact of genetic factors. Polymorphisms in the human genes coding for brain-derived neurotrophic factor and apolipoprotein E have been studied in the context of plasticity and stroke recovery and are discussed here in detail. Several processes involved in plasticity and stroke recovery, such as depression or pharmacotherapy effects, are modulated by other genetic polymorphisms and are also discussed. Finally, new genetic polymorphisms that have not been studied in the context of stroke are proposed as new directions for study. A better understanding of genetic influences on recovery and response to therapy might allow improved treatment after a number of forms of central nervous system injury.

Association of apolipoprotein E polymorphisms with cerebral vasospasm after spontaneous subarachnoid hemorrhage

Cerebral vasospasm (CVS) is the main complication of spontaneous subarachnoid hemorrhage (SAH), severely affecting clinical outcome of patients with SAH. Apolipoprotein E gene (APOE) is associated with prognosis of spontaneous subarachnoid hemorrhage (SAH), and APOEε4 allele is reported to be apt to CVS after SAH. The current study aimed to investigate the association of APOE polymorphisms with CVS after SAH. One hundred and eighty-five patients with spontaneous SAH were recruited in the study. APOE genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). CVS was judged by Transcranial Doppler sonography (TCD) combined with patients' condition. χ2-test and logistic regression analysis were done by SPSS (version 11.5). The distributions of APOE genotypes and alleles matched Hardy-Weinberg Law. In 185 patients, 21 of 32 (65.7%) patients with APOEε4 allele showed CVS, which was significantly different from those without APOE ε4 allele (56 of 153 patients, 36.6%, P=0.022). However, neither the presence of ε2 nor ε3 was significantly different from those absent of it (P>0.05). Logistic regression analysis demonstrated that ApoEε4 allele was a risk factor (OR=2.842. 95% CI 1.072-6.124. P=0.019) to predispose to CVS after adjusting for age, sex, hypertension or not, hyperlipemia or not, Fisher grade, and Hunt-Hess grade after SAH. Our finding suggests that the patients with APOEε4 allele predispose to CVS after spontaneous SAH.

Association of APOE polymorphism with the change of brain function in the early stage of aneurysmal subarachnoid hemorrhage

Recent studies have indicated that early brain injury may be responsible for the detrimental effects seen in patients after subarachnoid hemorrhage (SAH). In this study, we investigated the relationship between apolipoprotein E gene (APOE) polymorphism and the change of brain function in the early stage of aneurysmal SAH. A total of 79 patients admitted within 5 days after aneurysmal SAH were recruited in the study. Patient characteristics, such as age, gender, Fisher and Hunt-Hess grade were collected when admitted. Electroencephalogram (EEG) was recorded on admission and at 3-5 days after onset to assess the change of brain function of the patients in acute stage of SAH. The result of the second EEG recording was defined as EEG deterioration if the decrease in alpha wave frequency, increase in slow wave or decline in amplitude were observed when compared with the first EEG recording. The APOE polymorphism was determined in all patients by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Ten of 17 patients with APOEε4 (58.8%) showed the deteriorated EEGs, which was significantly different from those without APOEε4 (18 of 62 patients, 29.0%, p=0.023). However, neither the presence of ε2 nor of ε3 was significantly different from those absent of it (p>0.05). Univariate logistic regression analyses showed that both high Fisher grade (p=0.028, OR=2.917, 95% CI=1.124-7.572) and APOEε4 (p=0.027, OR=3.492, 95% CI=1.150-10.604) were risk factors to EEG aggravation after aneurysmal SAH. The association of APOEε4 for deteriorated EEG was more significant after adjustment for age, gender, Hunt-Hess grade on admission, and Fisher grade (p=0.007, OR=5.741, 95% CI=1.625-20.280). Our findings suggest that APOEε4 allele is a risk factor to brain function aggravation in the early stage of aneurysmal SAH, and it may contribute to early brain injury after SAH.

Cerebrovascular risk factors and preclinical memory decline in healthy APOE ε4 homozygotes

OBJECTIVE

To characterize the effects of cerebrovascular (CV) risk factors on preclinical memory decline in cognitively normal individuals at 3 levels of genetic risk for Alzheimer disease (AD) based on APOE genotype.

METHODS

We performed longitudinal neuropsychological testing on an APOE ε4 enriched cohort, ages 21-97. The long-term memory (LTM) score of the Auditory Verbal Learning Test (AVLT) was the primary outcome measure. Any of 4 CV risk factors (CVany), including hypercholesterolemia (CHOL), prior cigarette use (CIG), diabetes mellitus (DM), and hypertension (HTN), was treated as a dichotomized variable. We estimated the longitudinal effect of age using statistical models that simultaneously modeled the cross-sectional and longitudinal effects of age on AVLT LTM by APOE genotype, CVany, and the interaction between the two.

RESULTS

A total of 74 APOE ε4 homozygotes (HMZ), 239 ε4 heterozygotes (HTZ), and 494 ε4 noncarriers were included. APOE ε4 carrier status showed a significant quadratic effect with age-related LTM decline in all models as previously reported. CVany was associated with further longitudinal AVLT LTM decline in APOE ε4 carriers (p=0.02), but had no effect in noncarriers. When ε4 HTZ and HMZ were considered separately, there was a striking effect in HMZ (p<0.001) but not in HTZ. In exploratory analyses, significant deleterious effects were found for CIG (p=0.001), DM (p=0.03), and HTN (p=0.05) in APOE ε4 carriers only that remained significant only for CIG after correction for multiple comparisons.

CONCLUSION

CV risk factors influence age-related memory decline in APOE ε4 HMZ.

The role of diffusion tensor imaging in the study of cognitive aging

This chapter gives an overview of the role that diffusion tensor MRI (DTI) can play in the study of cognitive decline that is associated with advancing age. A brief overview of biological injury processes that impinge on the aging brain is provided, and their overall effect on the integrity of neural architecture is described. Cognitive decline associated with aging, and white matter connectivity degradation as a biological substrate for that decline, is then described. We then briefly describe the technology of DTI as a means for in vivo, non-invasive interrogation of white matter connectivity, and relate it to FLAIR, a more traditional MRI method for assessing white matter injury. We then survey the existing findings on relationships between aging-associated neuropathological processes and DTI measurements on one hand; and relationships between DTI measurements and late-life cognitive function on the other. We conclude with a summary of current research directions in relation to DTI studies of cognitive aging.

ApoE, MemorE, and EpilepsE

ApoE- ∊4 Is Associated with Reduced Memory in Long-Standing Intractable Temporal Lobe Epilepsy. Busch RM, Lineweaver TT, Naugle RI, Kim KH, Gong Y, Tilelli CQ, Prayson RA, Bingaman W, Najm IM, Diaz-Arrastia R. Neurology 2007;68(6):409–414. OBJECTIVE: To investigate the relationship between the apolipoprotein (ApoE) 4 allele and memory performance (verbal and nonverbal) in patients with medically intractable temporal lobe epilepsy (TLE) who underwent temporal lobectomy. METHODS: Presurgical and postsurgical memory performance was examined in 87 adult patients with TLE (4 = 22; non-4 = 65) to determine whether the expression of ApoE-4 may be associated with memory performance in this population and to examine how this relationship may be affected by duration of epilepsy. RESULTS: There was a significant interaction between ApoE-4 status and duration of epilepsy such that 4 carriers with a long duration of epilepsy demonstrated the poorest memory performance on both verbal and nonverbal measures. This relationship was observed both before and after temporal lobectomy, with little change in test performance over time. CONCLUSIONS: The ApoE-4 allele interacts with longstanding seizures to affect memory performance, both verbal and nonverbal, in patients with medically intractable temporal lobe epilepsy.

Genetic determinants of cerebral vasospasm, delayed cerebral ischemia, and outcome after aneurysmal subarachnoid hemorrhage

Despite extensive effort to elucidate the cellular and molecular bases for delayed cerebral injury after aneurysmal subarachnoid hemorrhage (aSAH), the pathophysiology of these events remains poorly understood. Recently, much work has focused on evaluating the genetic underpinnings of various diseases in an effort to delineate the contribution of specific molecular pathways as well as to uncover novel mechanisms. The majority of subarachnoid hemorrhage genetic research has focused on gene expression and linkage studies of these markers as they relate to the development of intracranial aneurysms and their subsequent rupture. Far less work has centered on the genetic determinants of cerebral vasospasm, the predisposition to delayed cerebral injury, and the determinants of ensuing functional outcome after aSAH. The suspected genes are diverse and encompass multiple functional systems including fibrinolysis, inflammation, vascular reactivity, and neuronal repair. To this end, we present a systematic review of 21 studies suggesting a genetic basis for clinical outcome after aSAH, with a special emphasis on the pathogenesis of cerebral vasospasm and delayed cerebral ischemia. In addition, we highlight potential pitfalls in the interpretation of genetic association studies, and call for uniformity of design of larger multicenter studies in the future.

Brain plasticity and genetic factors

Brain plasticity refers to changes in brain function and structure that arise in a number of contexts. One area in which brain plasticity is of considerable interest is recovery from stroke, both spontaneous and treatment-induced. A number of factors influence these poststroke brain events. The current review considers the impact of genetic factors. Polymorphisms in the human genes coding for brain-derived neurotrophic factor (BDNF) and apolipoprotein E (ApoE) have been studied in the context of plasticity and/or stroke recovery and are discussed here in detail. Several other genetic polymorphisms are indirectly involved in stroke recovery through their modulating influences on processes such as depression and pharmacotherapy effects. Finally, new genetic polymorphisms that have not been studied in the context of stroke are proposed as new directions for study. A better understanding of genetic influences on recovery and response to therapy might allow improved treatment after stroke.

Significance of apolipoprotein E in subarachnoid hemorrhage: neuronal injury, repair, and therapeutic perspectives--a review

Subarachnoid hemorrhage (SAH) strikes individuals at a young age with devastating neurologic consequences. Classic formulations that correlate complications and outcome with clinical variables do not explain all the heterogeneity that is usually found in clinical practice. The role of genetic predisposition has recently been investigated. Particular attention has been paid to the apolipoprotein E (APOE) genotype that encodes for a polymorphic protein existing as 3 isoforms (apoE2, apoE3, apoE4), products of alleles E2, E3, and E4 at a single gene locus. ApoE is produced by astrocytes and exerts complex neuroprotective functions that make it a hub of the biochemical network of SAH. The neuroprotective effectiveness of the apoE4 isoform is reduced with respect to the others and this has made the E4 allele a risk factor candidate. Recently published observational studies and meta-analyses suggested that the APOE genotype may strongly improve the usual predictive model with the possibility of optimizing clinical decisions according to the individual's needs. Furthermore, the clinical results, together with new biological insights, suggest that SAH may be a possible candidate for the ongoing research on apoE-based neuroprotective therapy. This article reviews the clinical studies, analyzes their methodology, and surveys the biological links between the physiopathology of SAH and apoE and the possible prospects.

Apolipoprotein E genotype and outcome after aneurysmal subarachnoid hemorrhage

Object

After aneurysmal subarachnoid hemorrhage (SAH), conflicting results concerning an association between the APOE genotype and impaired outcome have been reported. The authors tested prospectively whether APOE ε2 or ε4 allele–containing genotypes (ε2+ and ε4+) affect outcome after SAH.

Methods

Previous disease histories and clinical and radiological variables were recorded for 105 patients who were admitted within 48 hours after SAH. Fifteen patients (14%) had the ε2+ genotype and 31 (17%) had ε4+ genotypes. Factors predicting poor outcome according to the Glasgow Outcome Scale and cerebral infarction visible on CT scans obtained at 3 months after SAH were tested with multiple logistic regression analyses.

Results

Apolipoprotein E ε2 or ε4–containing genotypes were not associated with outcome, occurrence of cerebral infarction, or with any of their predictors, either in univariate or multivariate analysis. Poor outcome was predicted independently by the occurrence of intraventricular bleeding and intracerebral hematoma as well as by elevated levels of both plasma glucose and D-dimer, and delayed cerebral ischemia (p < 0.05 for each factor), and in univariate analysis only by clinical condition on admission and patient age. Cerebral infarction was predicted independently according to clinical condition on admission (p < 0.05), amount of subarachnoid blood (p < 0.01), duration of intraoperative parent artery clipping (p < 0.01), and body mass index (p < 0.05). In the univariate analysis only cerebral infarction was also predicted by patient age, intracerebral hematoma, and delayed cerebral ischemia.

Conclusions

Severity of bleeding for the most part predicts outcome after SAH; APOE polymorphisms seem to have no prognostic value for outcome after SAH. This result was in accordance with the findings from the largest ischemic stroke studies.

The on-line promotion and sale of nutrigenomic services

PURPOSE

Nutrigenomic researchers hope to improve health through personalized nutrition, but many consider the sale of nutrigenomic services to be premature. Few studies have evaluated the promotion and sales practices of organizations hosting nutrigenomic websites.

METHODS

Systematic search and analysis of websites promoting nutrigenomic services in October 2006.

RESULTS

Of the 64 organizations hosting websites, 29 organizations offered (24 of 29) or promoted (5 of 29) at-home testing and 26 organizations sold services on-line (17 of 26) or provided a direct link to on-line sales (9 of 26). A lack of transparency made it difficult to identify unique tests; however, three organizations were linked to 56% of all test mentions. Most organizations were healthcare/wellness service providers (50%) or laboratories/biotech companies (27%). Few organizations provided on-line information about laboratory certifications (20%), nutrigenomic test or research limitations (13%), test validity or utility (11%), or genetic counseling (9%). Affiliation opportunities were offered by 15 organizations.

CONCLUSIONS

Organizations did not provide adequate information about nutrigenomic services and at-home genetic testing. Affiliation opportunities and distribution agreements suggest the promotion and sale of nutrigenomic services will continue, increasing the importance of consumer and provider education. In absence of federal regulation, organizations promoting nutrigenomic services should equate websites to product labels and include information to facilitate informed decision-making.

Pharmacogenomic effects of apolipoprotein e on intracerebral hemorrhage

BACKGROUND AND PURPOSE

The purpose of the study was to evaluate the effect of APOE genotype and the feasibility of administering an apolipoprotein E-mimetic therapeutic to modify outcomes in a murine model of intracerebral hemorrhage.

METHODS

Intracerebral hemorrhage was induced via stereotactic injection of 0.1 U Clostridial collagenase into the left basal ganglia of wild-type and apolipoprotein-E targeted-replacement mice, consisting of either homozygous 3/3 or 4/4 genotypes. Animals were randomized to receive either vehicle or apolipoprotein E-mimetic peptide. Outcomes included functional neurological tests (21-point neuroseverity score and Rotorod latency) over the initial 7 days after injury, radiographic and histological hemorrhage size at 3 and 7 days, brain water content for cerebral edema at 24 hours, and quantitative polymerase chain reaction for inflammatory markers at 6, 24, and 48 hours.

RESULTS

Apolipoprotein-E targeted-replacement mice consisting of homozygous 3/3 demonstrated superior neuroseverity scores and Rotorod latencies over the first 3 days after intracerebral hemorrhage, decreased cerebral edema at 24 hours, and reduced upregulation of IL-6 and endothelial nitric oxide synthase at 6 hours when compared to their apolipoprotein-E targeted-replacement mice consisting of homozygous 4/4 counterparts. After intravenous administration of 1 mg/kg apolipoprotein E-mimetic peptide, both wild-type and apolipoprotein-E targeted-replacement mice consisting of homozygous 4/4 exhibited improved functional outcomes over 7 days after intracerebral hemorrhage, less edema at 24 hours, and reduced upregulation of IL-6 and endothelial nitric oxide synthase when compared to mice that did not receive the peptide.

CONCLUSIONS

Our data indicate that APOE genotype influences neurological outcome after intracerebral hemorrhage in a murine model. In particular APOE4 is associated with poor functional outcome and increased cerebral edema. Additionally, this outcome can be modified by the addition of an apolipoprotein E mimetic-peptide, COG1410.

Genetic polymorphisms for the study of multifactorial stroke

Single-gene disorders explain only a minority of stroke cases. Stroke represents a complex trait, which is usually assumed to be polygenic. On this topic, the role of a wide number of candidate genes has been investigated in stroke through association studies, with controversial results. Therefore, it is difficult for the clinician to establish the validity and the level of clinical applicability of the previously reported associations between genetic factors and stroke. This review is an update and an extensive analysis of the more recent association studies conducted in stroke. We evaluated a number of studies on several candidate genes (including F5, F2, FGA/FGB/FGG, F7, F13A1, vWF, F12, SERPINE1, ITGB3/PLA1/PLA2/ITGA2B, ITGA2, GP1BA, ACE, AGT, NOS3, APOE, LPL, PON1, PDE4D, ALOX5AP, MTHFR, MTR, and CBS), providing a final panel of genes and molecular variants. We categorized this panel in relation to the degree of association with stroke, supported by the results of meta-analyses and case-control studies. Our findings could represent a useful tool to address further molecular investigations and to realize more detailed meta-analyses.

Apolipoprotein E and neurological disease: therapeutic potential and pharmacogenomic interactions

The apolipoprotein E (apoE) polymorphism is emerging as a uniquely important genetic modifier that affects functional outcome from both acute and chronic neurological injuries. Recent attention has focused on common denominator mechanisms by which apoE might affect brain injury and/or brain repair responses in clinically diverse diseases. Although endogenous apoE likely serves several adaptive functions in the injured CNS, there is growing evidence that its effect on modifying brain inflammatory responses and providing protection from excitotoxic injury may be central to its protective properties. A more complete understanding of the role that apoE plays in the injured brain has led to novel therapeutic strategies for both acute and chronic neurological disease.