Intracerebral hemorrhage outcome: apolipoprotein E genotype, hematoma, and edema volumes

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.

Perihematomal Edema After Intracerebral Hemorrhage: An Update on Pathogenesis, Risk Factors, and Therapeutic Advances

Intracerebral hemorrhage (ICH) has one of the worst prognoses among patients with stroke. Surgical measures have been adopted to relieve the mass effect of the hematoma, and developing targeted therapy against secondary brain injury (SBI) after ICH is equally essential. Numerous preclinical and clinical studies have demonstrated that perihematomal edema (PHE) is a quantifiable marker of SBI after ICH and is associated with a poor prognosis. Thus, PHE has been considered a promising therapeutic target for ICH. However, the findings derived from existing studies on PHE are disparate and unclear. Therefore, it is necessary to classify, compare, and summarize the existing studies on PHE. In this review, we describe the growth characteristics and relevant underlying mechanism of PHE, analyze the contributions of different risk factors to PHE, present the potential impact of PHE on patient outcomes, and discuss the currently available therapeutic strategies.

Association of baseline hematoma and edema volumes with one-year outcome and long-term survival after spontaneous intracerebral hemorrhage: A community-based inception cohort study

BACKGROUND

Hospital-based studies have reported variable associations between outcome after spontaneous intracerebral hemorrhage and peri-hematomal edema volume.

AIMS

In a community-based study, we aimed to investigate the existence, strength, direction, and independence of associations between intracerebral hemorrhage and peri-hematomal edema volumes on diagnostic brain CT and one-year functional outcome and long-term survival.

METHODS

We identified all adults, resident in Lothian, diagnosed with first-ever, symptomatic spontaneous intracerebral hemorrhage between June 2010 and May 2013 in a community-based, prospective inception cohort study. We defined regions of interest manually and used a semi-automated approach to measure intracerebral hemorrhage volume, peri-hematomal edema volume, and the sum of these measurements (total lesion volume) on first diagnostic brain CT performed at ≤3 days after symptom onset. The primary outcome was death or dependence (scores 3-6 on the modified Rankin Scale) at one-year after intracerebral hemorrhage.

RESULTS

Two hundred ninety-two (85%) of 342 patients (median age 77.5 y, IQR 68-83, 186 (54%) female, median time from onset to CT 6.5 h (IQR 2.9-21.7)) were dead or dependent one year after intracerebral hemorrhage. Peri-hematomal edema and intracerebral hemorrhage volumes were colinear (R² = 0.77). In models using both intracerebral hemorrhage and peri-hematomal edema, 10 mL increments in intracerebral hemorrhage (adjusted odds ratio (aOR) 1.72 (95% CI 1.08-2.87); p = 0.029) but not peri-hematomal edema volume (aOR 0.92 (0.63-1.45); p = 0.69) were independently associated with one-year death or dependence. 10 mL increments in total lesion volume were independently associated with one-year death or dependence (aOR 1.24 (1.11-1.42); p = 0.0004).

CONCLUSION

Total volume of intracerebral hemorrhage and peri-hematomal edema, and intracerebral hemorrhage volume alone on diagnostic brain CT, undertaken at three days or sooner, are independently associated with death or dependence one-year after intracerebral hemorrhage, but peri-hematomal edema volume is not.

DATA ACCESS STATEMENT

Anonymized summary data may be requested from the corresponding author.

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.

Subarachnoid Hemorrhage Early Brain Edema Score (SEBES) as a radiographic marker of clinically relevant intracranial hypertension and unfavorable outcome after subarachnoid hemorrhage

BACKGROUND AND PURPOSE

The severity of early brain edema (EBE) after aneurysm rupture was reported to be strongly associated with the risk of poor outcome after aneurysmal subarachnoid hemorrhage (SAH). Using the recently developed Subarachnoid Hemorrhage Early Brain Edema Score (SEBES), we analyzed the predictors of EBE and its impact on complications related to intracranial pressure (ICP) increase after SAH and on poor outcome.

METHODS

All consecutive SAH cases treated between January 2003 and June 2016 with assessable SEBES were included (n = 745). Data on demographic characteristics, medical history, initial severity of SAH, need for conservative ICP treatment and decompressive craniectomy, occurrence of cerebral infarctions and unfavorable outcome at 6 months (modified Rankin scale score > 2) were collected. Univariable and multivariable analyses were performed.

RESULTS

Younger age (<55 years; adjusted odds ratio [aOR] 3.16, 95% confidence interval [CI] 2.28-4.38), female sex (aOR 1.64, 95% CI 1.16-2.31), poor initial clinical condition (World Federation of Neurosurgical Societies score 4-5; aOR 1.74, 95% CI 1.23-2.46), presence of intracerebral hemorrhage (aOR 1.63, 95% CI 1.12-2.36), hypothyroidism (aOR 0.60, 95% CI 0.37-0.98) and renal comorbidity (aOR 0.29, 95% CI 0.11-0.78) were independently associated with SEBES (scores 3-4). There was an independent association between SEBES 3-4 and the need for conservative ICP treatment (aOR 2.43, 95% CI 1.73-3.42), decompressive craniectomy (aOR 2.68, 95% CI 1.84-3.89), development of cerebral infarcts (aOR 2.24, 95% CI 1.53-3.29) and unfavorable outcome (aOR 1.48, 95% CI 1.0-2.17).

CONCLUSIONS

SEBES is a reliable predictor of ICP-related complications and poor outcome of SAH. Our findings highlight the need for further research of the impact of patients' demographic characteristics and comorbidities on the severity of EBE after SAH.

Apolipoprotein E Gene Polymorphisms Are Risk Factors for Spontaneous Intracerebral Hemorrhage: A Systematic Review and Meta-analysis

Intracerebral hemorrhage (ICH) is a serious clinical disease with high morbidity, whose pathogenesis might be related to apolipoprotein E (APOE) gene polymorphisms. To comprehensively evaluate the risk factors for ICH occurrence, we performed a meta-analysis. We searched online databases to identify eligible studies based on the relationship between APOE genetic polymorphisms and ICH occurrence risk. Specific and pooled odds ratios (ORs) were calculated and by assessing small study bias, we drew the relationship between APOE polymorphisms and ICH risk. We included 15 eligible studies in our study containing a total of 1642 ICH samples and 5545 normal controls. The comparison of ɛ4 and ɛ3 APOE genotypes revealed that specific and pooled ORs showed a significantly increased odds ratio in ICH patients with the ɛ4 genotype, indicating that ɛ4 gene is a risk factor for ICH occurrence, and the heterogeneity is acceptable. Similarly, it was found that the ɛ2 genotype also contributed to the incidence rate of ICH. However, after the subgroup analysis by ethnicity, this APOE genetic polymorphism acted as a harmful factor only in white populations, but did not show an effect in Asian populations. It was suggested that both ε2 and ε4 APOE alleles were risk factors for ICH in general. They were risk factors in white populations only, neither had a detectable effect in Asian populations after subgroup analysing by ethnicity.

Disparities in Functional Outcome After Intracerebral Hemorrhage Among Asians and Pacific Islanders

Background

Disparities in outcome after intracerebral hemorrhage (ICH) among Asians, Native Hawaiians, and other Pacific Islanders (NHOPI) have been inadequately studied. We sought to assess differences in functional outcome between Asians and NHOPI after ICH.

Methods

A multiracial prospective cohort study of ICH patients was conducted from 2011 to 2016 at a tertiary center in Honolulu, HI, USA to assess racial disparities in outcome after ICH. Favorable outcome was defined as 3-month modified Rankin Scale (mRS) score ≤2. Patients with no available 3-month functional outcome, race other than Asians and NHOPI, and baseline mRS > 0 were excluded. Multivariable analyses using logistic regression were performed to assess the impact of race on favorable outcome after adjusting for the ICH Score, early do-not-resuscitate (DNR) order and dementia/cognitive impairment.

Results

A total of 220 patients (161 Asians, 59 NHOPI) were studied. Overall, 65 (29.5%) achieved favorable outcome at 3 months. NHOPI were younger than Asians (p < 0.0001) and had higher prevalence of diabetes (p = 0.007), obesity (p < 0.0001), and lower prevalence of dementia/cognitive impairment (p = 0.02), early DNR order (p = 0.0004), and advance directive presence (p = 0.0005). NHOPI race was a predictor of favorable outcome in the unadjusted model [odds ratio (OR) 2.47, 95% confidence interval (CI): 1.32-4.62] and after adjusting for the ICH Score (OR 2.30, 95% CI: 1.06-4.97) but not in the final model (OR 2.04, 95% CI: 0.94-4.42). In the final model, the ICH Score was the only independent negative predictor of outcome (OR 0.26, 95% CI: 0.17-0.41 per point).

Conclusion

NHOPI are more likely to achieve favorable functional outcome after ICH compared with Asians even after controlling for ICH severity. However, this association was attenuated by the DNR and dementia/cognitive impairment status.

Apolipoprotein E as a novel therapeutic neuroprotection target after traumatic spinal cord injury

Apolipoprotein E (apoE), a plasma lipoprotein well known for its important role in lipid and cholesterol metabolism, has also been implicated in many neurological diseases. In this study, we examined the effect of apoE on the pathophysiology of traumatic spinal cord injury (SCI). ApoE-deficient mutant (apoE^-/-) and wild-type mice received a T9 moderate contusion SCI and were evaluated using histological and behavioral analyses after injury. At 3days after injury, the permeability of spinal cord-blood-barrier, measured by extravasation of Evans blue dye, was significantly increased in apoE^-/- mice compared to wild type. The inflammation and spared white matter was also significantly increased and decreased, respectively, in apoE^-/- mice compared to the wild type ones. The apoptosis of both neurons and oligodendrocytes was also significantly increased in apoE^-/- mice. At 42days after injury, the inflammation was still robust in the injured spinal cord in apoE^-/- but not wild type mice. CD45+ leukocytes from peripheral blood persisted in the injured spinal cord of apoE^-/- mice. The spared white matter was significantly decreased in apoE^-/- mice compared to wild type ones. Locomotor function was significantly decreased in apoE^-/- mice compared to wild type ones from week 1 to week 8 after contusion. Treatment of exogenous apoE mimetic peptides partially restored the permeability of spinal cord-blood-barrier in apoE^-/- mice after SCI. Importantly, the exogenous apoE peptides decreased inflammation, increased spared white matter and promoted locomotor recovery in apoE^-/- mice after SCI. Our results indicate that endogenous apoE plays important roles in maintaining the spinal cord-blood-barrier and decreasing inflammation and spinal cord tissue loss after SCI, suggesting its important neuroprotective function after SCI. Our results further suggest that exogenous apoE mimetic peptides could be a novel and promising neuroprotective reagent for SCI.

Apolipoprotein E polymorphism in aneurysmal subarachnoid haemorrhage in West Sweden

BACKGROUND AND PURPOSE

Aneurysmal subarachnoid haemorrhage (aSAH) is associated with high morbidity and mortality despite novel treatments. Genetic variability may explain outcome differences. Apolipoprotein E (ApoE) is a glycoprotein with a major role in brain lipoprotein metabolism. It has three isoforms encoded by distinct alleles: APOEε2, APOEε3 and APOEε4. The APOEε4 allele is associated with Alzheimer's disease and worse outcome after traumatic brain injury and ischaemic stroke. This prospective blinded study explored the influence of the APOEε4 polymorphism on the risk of aSAH, risk of cerebral vasospasm (CVS) and 1-year neurological outcome.

METHODS

The APOΕε4 polymorphism was analysed in 147 patients with aSAH. Allele and genotype frequencies were compared to those found in a gender- and area-matched control group of healthy individuals (n = 211). Early CVS was identified and treated according to neurointensive care unit (NICU) guidelines. Neurological deficit(s) at admittance and at 1-year follow-up visit was recorded. Neurological outcome was assessed by the National Institute of Health Stroke Scale, Barthel Index and the Extended Glasgow Outcome Scale.

RESULTS

APOEε4 and non-APOEε4 allele frequencies were similar in aSAH patients and healthy individuals. The presence of APOEε4 was not associated with the development of early CVS. We could not find an influence of the APOE polymorphism on 1-year neurological outcome between groups. Subgroup analyses of patients treated with surgical clipping vs endovascular coiling did not reveal any associations.

CONCLUSIONS

The APOEε4 polymorphism has no major influence on risk of aSAH, the occurrence of CVS or long-term neurological outcome after aSAH.

Hyperbaric oxygen preconditioning attenuates neuroinflammation after intracerebral hemorrhage in rats by regulating microglia characteristics

Intracerebral Hemorrhage (ICH) results in a detrimental neurologic disorder with complicated secondary brain injury. Hyperbaric oxygen preconditioning (HBOP) may be a safe and effective therapeutic method for ICH victims. Our previous studies have demonstrated that HBOP induces neuroprotection in cerebral ischemia and traumatic brain injury. This study aimed to investigate whether HBOP could alleviate neuroinflammation by regulating changes in microglia characteristics in a rat model of ICH. ICH was induced by autologous arterial blood injection, and animals were sacrificed at 12, 24, and 72 h post injury. We measured motor function and brain water content to evaluate the extent of inflammation. Fluoro-Jade C and TNF-α staining was used to characterize neuronal degeneration and neuroinflammatory cytokines, and immunofluorescence staining was performed for CD11b to show activated microglia and Iba-1 to show microglia. Our results indicate that motor dysfunction and brain water content are alleviated by HBOP, and Fluoro-Jade C staining demonstrates that neuron degeneration decreased in the HBOP group. The growth of Iba-1-positive microglia decreased in the HBOP group. Moreover, TNF-α was dynamically reduced in the HBOP group compared with the ICH group. CD11b-Iba-1 double staining demonstrated that the ratio of CD11b and Iba-1 was significantly decreased in the HBOP group. Overall, the data demonstrated that HBOP could significantly alleviate the ICH-induced neuroinflammation by regulating microglia characteristics changing. The phenomenon may propel the progress of the relation between microglia and HBOP and represent a novel target for ICH treatment.

Targeting secondary injury in intracerebral haemorrhage--perihaematomal oedema

Perihaematomal oedema (PHO) is an important pathophysiological marker of secondary injury in intracerebral haemorrhage (ICH). In this Review, we describe a novel method to conceptualize PHO formation within the framework of Starling's principle of movement of fluid across a capillary wall. We consider progression of PHO through three stages, characterized by ionic oedema (stage 1) and progressive vasogenic oedema (stages 2 and 3). In this context, possible modifiers of PHO volume and their value in identifying patients who would benefit from therapies that target secondary injury are discussed; the practicalities of using neuroimaging to measure PHO volume are also considered. We examine whether PHO can be used as a predictor of neurological outcome following ICH, and we provide an overview of emerging therapies. Our discussion emphasizes that PHO has clinical relevance both as a therapeutic target, owing to its augmentation of the mass effect of a haemorrhage, and as a surrogate marker for novel interventions that target secondary injury.

High dose deferoxamine in intracerebral hemorrhage (HI-DEF) trial: rationale, design, and methods

BACKGROUND

Hemoglobin degradation products, in particular iron, have been implicated in secondary neuronal injury following intracerebral hemorrhage (ICH). The iron chelator Deferoxamine Mesylate (DFO) exerts diverse neuroprotective effects, reduces perihematoma edema (PHE) and neuronal damage, and improves functional recovery after experimental ICH. We hypothesize that treatment with DFO could minimize neuronal injury and improve outcome in ICH patients. As a prelude to test this hypothesis, we conducted a Phase I, open-label study to determine the tolerability, safety, and maximum tolerated dose (MTD) of DFO in patients with ICH. Intravenous infusions of DFO in doses up to 62 mg/kg/day (up to a maximum of 6000 mg/day) were well-tolerated and did not seem to increase serious adverse events (SAEs) or mortality. We have initiated a multi-center, double-blind, randomized, placebo-controlled, Phase II clinical trial (High Dose Deferoxamine [HI-DEF] in Intracerebral Hemorrhage) to determine if it is futile to move DFO forward to Phase III efficacy evaluation.

METHODS

We will randomize 324 subjects with spontaneous ICH to either DFO at 62 mg/kg/day (up to a maximum daily dose of 6000 mg/day) or saline placebo, given by intravenous infusion for 5 consecutive days. Treatment will be initiated within 24 hours after ICH symptom onset. All subjects will be followed for 3 months and will receive standard of care therapy while participating in the study. At 3 months, the proportion of DFO-treated subjects with a good clinical outcome, assessed by modified Rankin Scale, will be compared to the placebo proportion in a futility analysis.

CONCLUSIONS

The Hi-Def trial is expected to advance our understanding of the pathopgysiology of secondary neuronal injury in ICH and will provide a crucial "Go/No Go" signal as to whether a Phase III trial to investigate the efficacy of DFO is warranted.

Apolipoprotein E gene polymorphism and the risk of intracerebral hemorrhage: a meta-analysis of epidemiologic studies

Background

Studies investigating the association between the apolipoprotein E (APOE) gene polymorphism and the risk of intracerebral hemorrhage (ICH) have reported conflicting results. We here performed a meta-analysis based on the evidence currently available from the literature to make a more precise estimation of this relationship.

Methods

Published literature from the National Library of Medline and Embase databases were retrieved. Odds ratio (OR) and 95% confidence interval (CI) were calculated in fixed- or random-effects models when appropriate. Subgroup analyses were performed by race.

Results

This meta-analysis included 11 case–control studies, which included 1,238 ICH cases and 3,575 controls. The combined results based on all studies showed that ICH cases had a significantly higher frequency of APOE ϵ4 allele (OR= 1.42, 95% CI= 1.21,1.67, P<0.001). In the subgroup analysis by race, we also found that ICH cases had a significantly higher frequency of APOE ϵ4 allele in Asians (OR= 1.52, 95% CI= 1.20,1.93, P<0.001) and in Caucasians (OR= 1.34, 95% CI= 1.07,1.66, P=0.009). There was no significant relationship between APOE ϵ2 allele and the risk of ICH.

Conclusion

Our meta-analysis suggested that APOE ϵ4 allele was associated with a higher risk of ICH.

Interaction between sex and apolipoprotein e genetic background in a murine model of intracerebral hemorrhage

Emerging evidence suggests sex and apolipoprotein E (APOE) genotype separately modify outcomes after intracerebral hemorrhage (ICH). We test the hypothesis that an interaction exists between sex and APOE polymorphism in modifying outcomes after ICH and is altered by administration of exogenous apoE-mimetic peptide. To define the effects of sex and APOE polymorphism in ICH, we created collagenase-induced ICH in male and female APOETR mice (targeted replacement mice homozygous for APOE3 or APOE4 alleles; n=12/group) and assessed performance on Rotarod (RR) and Morris water maze (MWM). To evaluate hematoma formation, we used hematoxylin and eosin staining at 24 h after injury (n=8/group). Using separate cohorts (n=12/group), apoE-mimetic peptide (COG1410 at 2 mg/kg) was administered after ICH, and mice were assessed by RR and MWM. Female mice outperformed male mice via RR and MWM by over 190% improvement through 7 days (RR) and 32 days (MWM) of testing after ICH (p<0.01). Female APOE3TR mice demonstrated improved function compared with all other groups (p<0.05) without any difference in hematoma volume at 24 h after injury in any group. Administration of a therapeutic apoE-mimetic peptide improved RR latencies through 7 days after ICH in male and female APOE4TR mice and MWM latencies over days 28-32 after ICH in male APOE4TR mice (p<0.05). Sex and APOE polymorphism influence functional outcomes in our murine model of ICH. Moreover, administration of exogenous apoE-mimetic peptide after injury differentially modifies the interaction between sex and APOE polymorphism.

New avenues for treatment of intracranial hemorrhage

OPINION STATEMENT

The mortality and morbidity from intracerebral hemorrhage (ICH) remain high despite advances in medical, neurologic, and surgical care during the past decade. The lessons learned from previous therapeutic trials in ICH, improved understanding of the pathophysiology of neuronal injury after ICH, and advances in imaging and pre-hospital assessment technologies provide optimism that more effective therapies for ICH are likely to emerge in the coming years. The potential new avenues for the treatment of ICH include a combination of increased utilization of minimally invasive surgical techniques with or without thrombolytic usage to evacuate or reduce the size of the hematoma; utilization of advanced imaging to improve selection of patients who are likely to benefit from reversal of coagulopathy or hemostatic therapy; ultra-early diagnosis and initiation of therapy in the ambulance; and the use of novel drugs to target the secondary injury mechanisms, including the inflammatory cascade, perihematomal edema reduction, and hemoglobin degradation products-mediated toxicity.

Association of serum glucose concentrations during acute hospitalization with hematoma expansion, perihematomal edema, and three month outcome among patients with intracerebral hemorrhage

BACKGROUND

There is some evidence that hyperglycemia increases the rate of poor outcomes in patients with intracerebral hemorrhage (ICH). We explored the relationship between various parameters of serum glucose concentrations measured during acute hospitalization and hematoma expansion, perihematomal edema, and three month outcome among subjects with ICH.

METHODS

A post-hoc analysis of a multicenter prospective study recruiting subjects with ICH and elevated systolic blood pressure (SBP) ≥170 mmHg who presented within 6 h of symptom onset was performed. The serum glucose concentration was measured repeatedly up to 5 times over 3 days after admission and change over time was characterized using a summary statistic by fitting the linear regression model for each subject. The admission glucose, glucose change between admission and 24 hour glucose concentration, and estimated parameters (slope and intercept) were entered in the logistic regression model separately to predict the functional outcome as measured by modified Rankin scale (mRS) at 90 days (0-3 vs. 4-6); hematoma expansion at 24 h (≤33 vs. >33%); and relative perihematomal edema expansion at 24 h (≤40 vs. >40%).

RESULTS

A total of 60 subjects were recruited (aged 62.0 ±15.1 years; 56.7% men). The mean of initial glucose concentration (±standard deviation) was 136.7 mg/dl (±58.1). Thirty-five out of 60 (58%) subjects had a declining glucose over time (negative slope). The risk of poor outcome (mRS 4-6) in those with increasing serum glucose levels was over two-fold relative to those who had declining serum glucose levels (RR = 2.64, 95% confidence interval [CI]: 1.03, 6.75). The RRs were 2.59 (95% CI: 1.27, 5.30) for hematoma expansion >33%; and 1.25 (95% CI: 0.73, 2.13) for relative edema expansion >40%.

CONCLUSIONS

Decline in serum glucose concentration correlated with reduction in proportion of subjects with hematoma expansion and poor clinical outcome. These results provide a justification for a randomized controlled clinical trial to evaluate the efficacy of aggressive serum glucose reduction in reducing death and disability among patients with ICH.

Apolipoproteins: metabolic role and clinical biochemistry applications

Lipoprotein metabolism is dependent on apolipoproteins, multifunctional proteins that serve as templates for the assembly of lipoprotein particles, maintain their structure and direct their metabolism through binding to membrane receptors and regulation of enzyme activity. The three principal functions of lipoproteins are contribution to interorgan fuel (triglyceride) distribution (by means of the fuel transport pathway), to the maintenance of the extracellular cholesterol pool (by means of the overflow pathway) and reverse cholesterol transport. The most important clinical application of apolipoprotein measurements in the plasma is in the assessment of cardiovascular risk. Concentrations of apolipoprotein B and apolipoprotein AI (and their ratio) seem to be better markers of cardiovascular risk than conventional markers such as total cholesterol and LDL-cholesterol. Apolipoprotein measurements are also better standardized than the conventional tests. We suggest that measurements of apolipoprotein AI and apolipoprotein B are included as a part of the specialist lipid profile. We also suggest that lipoprotein (a) should be measured as part of the initial assessment of dyslipidaemias because of its consistent association with cardiovascular risk. Genotyping of apolipoprotein E isoforms remains useful in the investigation of mixed dyslipidaemias. Lastly, the role of postprandial metabolism is increasingly recognized in the context of atherogenesis, obesity and diabetes. This requires better markers of chylomicrons, very-low-density lipoproteins and remnant particles. Measurements of apolipoprotein B48 and remnant lipoprotein cholesterol are currently the key tests in this emerging field.

A high cholesterol diet given to apolipoprotein E-knockout mice has a differential effect on the various neurotrophin systems in the hippocampus

Apolipoprotein E (apoE) is one of the major transporters of cholesterol in the body and is essential for maintaining various neural functions in the brain. Given that hypercholesterolemia is a risk factor in Alzheimer's disease (AD), it has been suggested that altered cholesterol metabolism may be involved in the development of the pathogenesis, including neural degeneration, commonly observed in AD patients. Neurotrophic factors and their receptors, which are known to regulate various neural functions, are also known to be altered in various neurodegenerative diseases. We therefore hypothesized that cholesterol metabolism may itself influence the neurotrophin system within the brain. We decided to investigate this possibility by modulating the amount of dietary cholesterol given to apoE-knockout (apoE-KO) and wild-type (WT) mice, and examining the mRNA expression of various neurotrophin ligands and receptors in their hippocampal formations. Groups of eight-week-old apoE-KO and WT mice were fed a diet containing either "high" (HCD) or "normal" (ND) levels of cholesterol for a period of 12 weeks. We found that high dietary cholesterol intake elevated BDNF mRNA expression in both apoE-KO and WT mice and TrkB mRNA expression in apoE-KO animals. On the other hand, NGF and TrkA mRNA levels remained unchanged irrespective of both diet and mouse type. These findings indicate that altered cholesterol metabolism induced by HCD ingestion combined with apoE deficiency can elicit a differential response in the various neurotrophin ligand/receptor systems in the mouse hippocampus. Whether such changes can lead to neural degeneration, and the mechanisms that may be involved in this, awaits further research.

Safety and tolerability of deferoxamine mesylate in patients with acute intracerebral hemorrhage

BACKGROUND AND PURPOSE

Treatment with the iron chelator, deferoxamine mesylate (DFO), improves neurological recovery in animal models of intracerebral hemorrhage (ICH). We aimed to evaluate the feasibility, safety, and tolerability of varying dose-tiers of DFO in patients with spontaneous ICH, and to determine the maximum tolerated dose to be adopted in future efficacy studies.

METHODS

This was a multicenter, phase-I, dose-finding study using the Continual Reassessment Method. DFO was administered by intravenous infusion for 3 consecutive days, starting within 18 hours of ICH onset. Subjects underwent repeated clinical assessments through 90 days, and computed tomography neuroimaging pre- and post-drug-administration.

RESULTS

Twenty subjects were enrolled onto 5 dose tiers, starting with 7 mg/kg per day and ending with 62 mg/kg per day as the maximum tolerated dose. Median age was 68 years (range, 50-90); 60% were men; and median Glasgow Coma Scale and National Institutes of Health Stroke Scale scores on admission were 15 (5-15) and 9 (0-39), respectively. ICH location was lobar in 40%, deep in 50%, and brain stem in 10%; intraventricular hemorrhage was present in 15%. DFO was discontinued because of adverse events in 2 subjects (10%). Six subjects (30%) experienced 12 serious adverse events, none of which were drug-related. DFO infusions were associated with mild blood-pressure-lowering effects. Fifty percent of patients had modified Rankin scale scores ≤2, and 39% had modified Rankin scale scores of 4 to 6 on day 90; 15% died.

CONCLUSIONS

Consecutive daily infusions of DFO after ICH are feasible, well-tolerated, and not associated with excessive serious adverse events or mortality. Our findings lay the groundwork for future studies to evaluate the efficacy of DFO in ICH.

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.

Effect of systolic blood pressure reduction on hematoma expansion, perihematomal edema, and 3-month outcome among patients with intracerebral hemorrhage: results from the antihypertensive treatment of acute cerebral hemorrhage study

BACKGROUND

Evidence indicates that systolic blood pressure (SBP) reduction may reduce hematoma expansion in patients with intracerebral hemorrhage (ICH) who are initially seen with acute hypertensive response.

OBJECTIVE

To explore the relationship between different variables of SBP reduction and hematoma expansion, perihematomal edema, and 3-month outcome among patients with ICH.

DESIGN

Post hoc analysis of a traditional phase 1 dose-escalation multicenter prospective study.

SETTING

Emergency departments and intensive care units.

PATIENTS

Patients having ICH with an elevated SBP of at least 170 mm Hg who were seen within 6 hours of symptom onset.

INTERVENTION

Systolic blood pressure reduction using intravenous nicardipine hydrochloride targeting 3 tiers of sequentially escalating SBP reduction goals (170-199, 140-169, or 110-139 mm Hg).

MAIN OUTCOME MEASURES

We evaluated the effect of SBP reduction (relative to initial SBP) on the following: hematoma expansion (defined as an increased intraparenchymal hemorrhage volume >33% on 24-hour vs baseline computed tomographic [CT] images), higher perihematomal edema ratio (defined as a >40% increased ratio of edema volume to hematoma volume on 24-hour vs baseline CT images), and poor 3-month outcome (defined as a modified Rankin scale score of 4-6).

RESULTS

Sixty patients (mean [SD] age, 62.0 [15.1] years; 34 men) were recruited (18, 20, and 22 patients in each of the 3 SBP reduction goal tiers). The median area under the curve (AUC) (calculated as the area between the hourly SBP measurements over 24 hours and the baseline SBP) was 1360 (minimum, 3643; maximum, 45) U. Comparing patients having less vs more aggressive SBP reduction based on 24-hour AUC analysis, frequencies were 32% vs 17% for hematoma expansion, 61% vs 40% for higher perihematomal edema ratio, and 46% vs 38% for poor 3-month outcome (P > .05 for all). The median SBP reductions were 54 mm Hg at 6 hours and 62 mm Hg at 6 hours from treatment initiation. Comparing patients having equal to or less vs more than the median SBP reduction at 2 hours, frequencies were 21% vs 31% for hematoma expansion, 42% vs 57% for higher perihematomal edema ratio, and 35% vs 48% for poor 3-month outcome (P > .05 for all).

CONCLUSIONS

We found no significant relationship between SBP reduction and any of the outcomes measured herein; however, the Antihypertensive Treatment of Acute Cerebral Hemorrhage study was primarily a safety study and was not powered for such end points. The consistent favorable direction of these associations supports further studies with an adequately powered randomized controlled design to evaluate the efficacy of aggressive pharmacologic SBP reduction.

Apolipoprotein E modifies neurological outcome by affecting cerebral edema but not hematoma size after intracerebral hemorrhage in humans

INTRODUCTION

To address the mechanisms by which apoE polymorphism affects functional outcome after intracerebral hemorrhage in humans, we tested the hypothesis that the presence of the APOE4 allele results in amplified inflammatory responses and increased cerebral edema.

METHODS

We prospectively enrolled and collected data on 21 adult patients consecutively admitted to Duke University Hospital with supratentorial intracerebral hematoma including hemorrhage volume, midline shift, modified Rankin Score, Glasgow Outcome Score, and APOE genotype. Hemorrhage size (cm(3)) and midline shift (mm), at the level of the thalamus, were measured by computed tomography within 36 hours of admission. Rankin and Glasgow Scores were determined at discharge. Student's t-test was used to analyze hemorrhage size, midline shift, and Glasgow Outcome Score and logistical regression were used to measure allele affect on modified Rankin Score. When analyzing modified Rankin Score, patients were grouped by favorable outcome (0-2) or unfavorable (3-6).

RESULTS

Out of 21 patients, 11 possessed at least 1 APOE4 allele (APOE4+). There was no difference in hemorrhage volume (25.8 v 38.3 mm for APOE4- v APOE4+, respectively) between the groups, but there was a significant difference in midline shift (P = .04, 0.7 v 4 mm). Functional outcomes were worse for the patients possessing at least 1 APOE4 allele (P = .04)

CONCLUSION

The presence of APOE4 is associated with poor functional outcomes in humans after intracerebral hemorrhage. Our data suggest that the mechanism for this may be increased cerebral edema and not larger hematoma volume.

Modulating effect of apolipoprotein E polymorphisms on secondary brain insult and outcome after childhood brain trauma

OBJECTIVE

The aim of this study was to determine the relationship between apolipoprotein E (APO E) alleles, the amount of cerebral perfusion pressure (CPP) insult and outcome in children after brain trauma.

MATERIALS AND METHODS

In a prospective two-centre case-control study, the APO E genotypes of 65 critically ill children admitted after brain trauma were correlated with age-related CPP insult quantification, conscious state at the time of discharge from intensive care and global outcome at 6 months post-injury. One hundred sixty healthy age- and sex-matched children were genotyped as controls.

RESULTS

The CPP insult level among the e4 carriers with poor outcome was significantly less than the non-e4 carriers (p=0.03). Homozygotic e3 patients with good recovery did so despite having suffered nearly 26 times more CPP insult than those who were not e3 homzygous (p=0.02).

CONCLUSION

Different APO E alleles may potentially affect cerebral ischaemic tolerance differently in children after brain trauma.

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.

Apolipoprotein E, amyloid-beta, and blood-brain barrier permeability in Alzheimer disease

There is increasing evidence for blood-brain barrier (BBB) compromise in Alzheimer disease (AD). The presence of the epsilon4 allele of the apolipoprotein E (apoE) gene is a risk factor for sporadic AD. Apolipoprotein E is essential both for maintenance of BBB integrity and for the deposition of fibrillar amyloid-beta (Abeta) that leads to the development of Abeta plaques in AD and to cerebral amyloid angiopathy. This review investigates the relationships between apoE, Abeta, and the BBB in AD. Alterations in the expression and distribution of the BBB Abeta transporters receptor for advanced glycation end-products and low-density lipoprotein receptor-related protein 1 in AD and the potential roles of apoE4 expression in adversely influencing Abeta burden and BBB permeability are also examined. Because both apoE and Abeta are ligands for low-density lipoprotein receptor-related protein 1, all 3 molecules are present in AD plaques, and most AD plaques are located close to the cerebral microvasculature. The interactions of these molecules at the BBB likely influence metabolism and clearance of Abeta and contribute to AD pathogenesis. Therapeutic alternatives targeting apoE/Abeta and sealing a compromised BBB are under development for the treatment of AD.

Apolipoprotein E epsilon4 allele and outcomes of traumatic spinal cord injury

BACKGROUND/OBJECTIVE

To test the hypothesis that apolipoprotein E (APOE) polymorphisms are associated with outcomes after spinal cord injury (SCI).

METHODS

Retrospective cohort study, from rehabilitation admission to discharge.

PARTICIPANTS

Convenience sample of 89 persons with cervical SCI (C3-C8) treated from 1995 through 2003. Median age was 30 years (range 14-70); 67 were male (75%) and 83 were white (93%).

MAIN OUTCOME MEASURES

American Spinal Injury Association (ASIA) motor and sensory scores, ASIA Impairment Scale (AIS), time from injury to rehabilitation admission, and length of stay (LOS) in rehabilitation.

RESULTS

Subjects with an APOE epsilon4 allele (n = 15; 17%) had significantly less motor recovery during rehabilitation than did individuals without an epsilon4 allele (median 3.0 vs 5.5; P < 0.05) and a longer rehabilitation LOS (median 106 vs 89 days; P = 0.04), but better sensory-pinprick recovery (median 5.0 vs 2.0; P= 0.03). There were no significant differences by APOE epsilon4 allele status in sensory-light touch recovery, likelihood of improving AIS Grade, or time from injury to rehabilitation admission.

CONCLUSIONS

APOE epsilon4 allele was associated with differences in neurological recovery and longer rehabilitation LOS. Genetic factors may be among the determinants of outcome after SCI and warrant further study.

Apolipoprotein E4 allele presence and functional outcome after severe traumatic brain injury

Presence of the apolipoprotein E (APOE) 4 allele has been associated with increased incidence and faster progression of neurodegenerative diseases, poorer recovery from neurologic insult, and decreased cognitive function in the well-elderly. The specific association between APOE genotype and recovery from severe traumatic brain injury (TBI) is conflicting with many groups finding the APOE 4 allele to be associated with poorer outcome while others have found no association. The purpose of this study was to investigate the association between APOE 4 allele presence and recovery during the two years after injury from severe TBI in light of other potential covariates, such as age, race, gender, hypotension or hypoxia before hospital admission and severity of injury. APOE genotype was determined for 123 subjects with severe TBI. Glasgow outcome score (GOS) and mortality were collected at 3, 6, 12, and 24 months after injury. Results showed individuals improved over the two year period following injury and those with the 4 allele had a slower recovery rate than those without the APOE 4 allele over the two year period. We did not however find significant differences in GOS at individual time points when controlling for other covariates. Our findings suggest that APOE 4 allele presence influences recovery rate from severe TBI independent of other covariates. The findings of this study are unique in that they address not only the relationship between APOE 4 allele presence and outcome from severe TBI, but also describe differences in trajectory of recovery by APOE 4 allele presence.

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

BACKGROUND

Rodent models of acute ischaemic stroke and head injury suggest that apolipoprotein E (APOE) genotype influences neuronal repair, regeneration and survival after brain injury. Possession of an APOE epsilon4 allele is associated with poor outcome after head injury in clinical studies. APOE might therefore influence outcome after acute stroke in humans.

OBJECTIVE AND METHODS

To comprehensively search, identify, assess and carry out meta-analyses of studies reporting on the association between APOE and the combined outcome of death or dependency, or death alone, several months after ischaemic stroke, intracerebral haemorrhage (ICH) or subarachnoid haemorrhage (SAH).

RESULTS

Main analyses included data from nine studies on 2262 patients (1453 with ischaemic stroke, 199 with ICH and 610 with SAH). Overall, epsilon4+ genotypes were not significantly associated with risk of death or dependency several months after stroke. However, there was significant heterogeneity between studies, and between the three pathological types of stroke. Epsilon4+ genotypes were associated with increased death or dependency after SAH (relative risk (RR) 1.40, 95% confidence interval (CI) 1.06 to 1.84), with a trend towards a similar association with ICH (RR 1.38, 95% CI 0.99 to 1.92), but not with ischaemic stroke (RR 0.98, 95% CI 0.85 to 1.12). Results were similar for death alone.

CONCLUSIONS

APOE may differentially affect outcome after the three main pathological types of stroke. Further, large studies are needed to confirm or refute these findings, and to assess the possibility of an interaction between the effects of APOE and age.

Apolipoprotein E knockout mice have accentuated malnutrition with mucosal disruption and blunted insulin-like growth factor I responses to refeeding

Apolipoprotein E (apoE) is synthesized mainly in the liver and in the brain and is critical for cholesterol metabolism and recovery from brain injury. However, although apoE mRNA increases at birth, during suckling, and after fasting in rat liver, little is known about its role in early postnatal development. Using an established postnatal malnutrition model and apoE knock-out (ko) mice, we examined the role of apoE in intestinal adaptation responses to early postnatal malnutrition. Wild-type and apoE-ko mice were separated from their lactating dams for defined periods each day (4 hours on day 1, 8 hours on day 2, and 12 hours thereafter). We found significant growth deficits, as measured by weight gain or tail length, in the apoE-ko mice submitted to a malnutrition challenge, as compared with malnourished wild type, especially during the second week of postnatal development (P < .05). In addition, apoE-ko animals failed to show growth catch-up after refeeding, compared with wild-type malnourished controls. Furthermore, we found shorter crypts and reduced villus height and area in the apoE-ko malnourished mice, compared with controls, after refeeding. Insulinlike growth factor 1 expression was also blunted in the ileum in apoE-ko mice after refeeding, compared with wild-type controls, which exhibited full insulinlike growth factor 1 expression along the intestinal crypts, villi, and in the muscular layer. Taken together, these findings suggest the importance of apoE in coping with a malnutrition challenge and during the intestinal adaptation after refeeding.

Premorbid effects of APOE on synaptic proteins in human temporal neocortex

APOE affects the risk of Alzheimer's disease (AD) and course of several other neurologic diseases. Experimental studies suggest that APOE influences synaptogenesis. We measured the concentration of two presynaptic proteins, synaptophysin and syntaxin 1, and also postsynaptic density-95 (PSD95), in superior temporal cortex from 42 AD and 160 normal brains, and determined the APOE genotypes. The concentration of both presynaptic proteins was approximately two-thirds lower in AD than normal brains and that of PSD95 one-third lower. No effect of APOE on synaptic proteins was found in advanced AD. However, in normal brain, epsilon4 was associated with lower concentrations of all three synaptic proteins and epsilon2 with significantly elevated PSD95 (p=0.03). A combined measure of synaptic proteins showed a significant linear decrease from epsilon2 through epsilon3 to varepsilon4 (p=0.01). APOE influences the concentration of synaptic proteins in normal superior temporal cortex and may thereby affect the response to injury, and the risk and outcome of a range of neurologic diseases.

Location characteristics of early perihaematomal oedema

BACKGROUND

The natural history and triggers of perihaematomal oedema (PHO) remain poorly understood. Cerebral amyloid angiopathy (a common cause of lobar haemorrhage) has localised anticoagulant and thrombolytic properties, which may influence PHO. We hypothesised that early (within 24 hours) oedema to haematoma volume ratios are smaller in patients with lobar intracerebral haemorrhage (ICH) than in patients with deep ICH.

METHODS

Haematoma and PHO volumes were measured in consecutive patients admitted to an acute stroke unit with a diagnosis of spontaneous supratentorial ICH proven by computed tomography. The oedema to haematoma volume ratios were calculated and compared in patients with lobar ICH and deep ICH.

RESULTS

In total, 44 patients with ICH were studied: 19 patients had deep ICH, median haematoma volume 8.4 ml (interquartile range (IQR) 4.8 to 20.8), median PHO 8.2 ml (2.8 to 16), and 25 had lobar ICHs, median haematoma volume 17.6 ml (6.6 to 33.1) and median oedema volume 10.2 ml (3.4 to 24.2). Patients with lobar ICH were older than those with deep ICH (65.7 v 57.4 years, p = 0.009) but ICH location did not differ by sex or race. There was no evidence that haematoma or oedema volumes were related to type of ICH (p = 0.23, p = 0.39 respectively). The median oedema to haematoma volume ratios were similar in patients with lobar and deep ICH (0.67 v 0.58, p = 0.71). Controlling for age, sex, and race made little difference to these comparisons.

CONCLUSIONS

There are no major location specific differences in PHO volumes within 24 hours of ICH onset. Deep and lobar ICH may have common therapeutic targets to reduce early PHO.

Association of APOE e4 and cerebrovascular pathology in traumatic brain injury

BACKGROUND

Previous studies have found the e4 allele of the apolipoprotein E gene (APOE e4) is associated with an unfavourable outcome after head injury, but this has not been related to specific pathological features.

OBJECTIVES

This study tested the postulate that head injured patients with APOE e4, amounting to approximately a third of the population, are selectively predisposed to one or more of the different pathological features that constitute the response to traumatic brain injury (TBI), and that this underlies the association of APOE e4 with poor clinical outcome.

METHODS

Included in the study were 239 fatal cases of TBI (1987-1999) for which APOE genotypes were determined from archival tissue. For each case, specific pathological features of trauma were recorded by researchers blinded to the APOE e4 status. Of the 239 cases examined, 83 (35%) were APOE e4 carriers and 156 (65%) were non-carriers.

RESULTS

Possession of APOE e4 was associated with a greater incidence of moderate or severe contusions (42% v 30% for carriers versus e4 non-carriers; p = 0.05) and there was a trend towards a greater incidence of severe ischaemic brain damage (54% v 42%; p = 0.08). Significant differences were not noted between the other pathological features examined.

CONCLUSIONS

Possession of APOE e4 is associated with a greater incidence of moderate/severe contusional injury and severe ischaemic brain damage in fatal cases of TBI. This may be relevant to the relatively poor outcome from traumatic brain injury in patients with APOE e4 identified in clinical studies.

Mechanisms of brain injury after intracerebral haemorrhage

The past decade has resulted in a rapid increase in knowledge of mechanisms underlying brain injury induced by intracerebral haemorrhage (ICH). Animal studies have suggested roles for clot-derived factors and the initial physical trauma and mass effect as a result of haemorrhage. The coagulation cascade (especially thrombin), haemoglobin breakdown products, and inflammation all play a part in ICH-induced injury and could provide new therapeutic targets. Human imaging has shown that many ICH continue to expand after the initial ictus. Rebleeding soon after the initial haemorrhage is common and forms the basis of a current clinical trial using factor VIIa to prevent rebleeding. However, questions about mechanisms of injuries remain. There are conflicting data on the role of ischaemia in ICH and there is uncertainty over the role of clot removal in ICH therapy. The next decade should bring further information about the underlying mechanisms of ICH-induced brain injury and new therapeutic interventions for this severe form of stroke. This review addresses our current understanding of the mechanisms underlying ICH-induced brain injury.

Genetic influences on outcome following acute neurological insults

PURPOSE OF REVIEW

To examine the evidence for a genetic influence on clinical outcome after a variety of acute neurologic events.

RECENT FINDINGS

Clinical outcome after brain injury is variable and cannot easily be predicted. It has been proposed that genetic polymorphisms may have an important role in determining outcome from a number of conditions, including acute neurologic events. Apolipoprotein E, an important mediator of cholesterol and lipid transport in the brain, is coded by a polymorphic gene (APOE). The APOE epsilon4 allele has been associated with unfavorable outcome after traumatic brain injury (TBI), hemorrhagic stroke and subarachnoid hemorrhage (SAH). Genes involved in other pathophysiological processes, such as cytokine genes in neuroinflammation, are now being implicated. For example interleukin-6 (IL-6) promoter polymorphisms are a risk factor for poor outcome after ischemic stroke, and may have an effect after traumatic brain injury. The emerging importance of a number of other gene polymorphisms is outlined in the review.

SUMMARY

There is evidence demonstrating the epsilon4 allele of APOE predisposes to poor outcome after TBI, hemorrhagic stroke and SAH, but not ischemic stroke. The reason for this difference is unclear but it suggests there may be differences in the key mechanisms underlying the response to different types of insult. The role of other gene polymorphisms is being increasingly explored but there is still a need for larger prospective studies looking at larger panels of gene polymorphisms.

Genes and outcome after aneurysmal subarachnoid haemorrhage

OBJECTIVES

Initial and secondary ischaemia are important determinants of outcome after subarachnoid haemorrhage (SAH). Cerebral ischaemia is a potent stimulus for expression of genes that may influence recovery.We investigated whether functional polymorphisms in the apolipoprotein E (APOE), insulin-like growth factor-1 (IGF-1), tumor necrosis factor-A (TNF-A), interleukin-1A (IL-1A), interleukin-1B (IL-1B), and interleukin-6 (IL-6) genes are related with outcome after aneurysmal SAH.

METHODS

Genotyping of the polymorphisms was performed in a consecutive series of 167 patients with aneurysmal SAH. The risk of a poor outcome was analysed with logistic regression with adjustment for prognostic factors for outcome after SAH, using the homozygotes for the wild type alleles as a reference.

RESULTS

Patients carrying any IGF-1 non-wild type allele had a lower risk of a poor outcome (OR 0.4, 95% CI 0.2-1.0), while carriers of the TNF-A non-wild type allele had a higher risk (OR 2.3, 95% CI 1.0-5.4). We could not demonstrate an association with outcome for APOE (APOE epsilon4 OR 0.4, 95% CI 0.1-1.2; APOE epsilon2 OR 0.7, 95% CI 0.2-2.4), IL-1A (OR 1.8, 95% CI 0.8-4.0), IL-1B (OR 0.7, 95% CI 0.3-1.5) and IL-6 (OR 0.7, 95% CI 0.3-1.8) polymorphisms.

CONCLUSIONS

Variation in some genes that are expressed after cerebral ischaemia may partly explain the large differences in outcome between patients with aneurysmal SAH. SAH patients homozygote for the IGF-1 wild type allele or carriers of the TNF-A non-wild type allele have a higher risk of poor outcome. Additional studies in other populations are needed to assess the generalisability of our results.

Cerebral amyloid angiopathy in traumatic brain injury: association with apolipoprotein E genotype

OBJECTIVE

In view of the association of the apolipoprotein E (APOE) epsilon 4 allele with poor outcome after traumatic brain injury we determined the frequency of cerebral amyloid angiopathy (CAA) and the extent of haemorrhagic pathology in relation to APOE genotype in an autopsy series of 88 head injured cases.

METHODS

Tissue sections from the frontal and temporal lobes were immunostained for amyloid-beta peptide (A beta) and stained for Congo red to identify vascular amyloid pathology. A semiquantitative assessment of contusions, the total contusion index, was used to estimate the severity of the haemorrhagic pathology. APOE genotypes were determined by polymerase chain reaction of genomic DNA extracted from paraffin embedded tissue sections.

RESULTS

CAA was present in 7/40 (18%) epsilon 4 carriers compared with 1/48 (2%) non-epsilon 4 carriers (p = 0.021, 95% confidence interval (CI) for difference in proportions with CAA 3% to 29%) with 6/40 (4 with CAA) epsilon 4 carriers being homozygotes. Thus the risk of having CAA for epsilon 4 carriers was 8.4 times that for the non-epsilon 4 carriers. However, there was no clear tendency for patients with CAA to have more severe or more numerous contusions (median contusion index 19 (CAA) v 14.5, p = 0.23, 95% CI for difference in medians -5 to 14).

CONCLUSIONS

Presence of CAA in head injured cases was significantly associated with possession of an APOE epsilon 4 allele but not with the severity of contusions.

There is no evidence of an association in children and teenagers between the apolipoprotein E epsilon4 allele and post-traumatic brain swelling

Traumatic brain injury (TBI) is an important cause of mortality and disability in children and teenagers. A particular feature of the neuropathology at post-mortem is brain swelling. The cause of the swelling in some cases is not known, while in others it is associated with traumatic axonal injury or hypoxia. Apolipoprotein E (APOE) epsilon4 allele is known to be an important genetic determinant of outcome in children after TBI. We hypothesized a relationship between possession of APOEepsilon4 and diffuse traumatic brain swelling. A total of 165 cases aged between 2 and 19 years were identified from the department's tissue archive. APOE genotype was determined by polymerase chain reaction (PCR) in 106 cases. Bilateral swelling was present in 44 cases (11 with APOEepsilon4), unilateral swelling in 25 cases (7 with APOEepsilon4) and in 36 cases (9 with APOEepsilon4) there was no evidence of brain swelling. There was no significant relationship between possession of APOEepsilon4 and the presence of cerebral swelling (chi(2) = 0.09, df = 2, P = 0.96). The 95% confidence interval for difference in proportions with swelling in those with and without the APOE epsilon4 is -19% to 22%. Thus, a significant relationship was not found between diffuse brain swelling and possession of APOEepsilon4, and in this cohort of patients there was an identifying cause of the brain swelling in all cases.

Cell column chromatography: a new research tool to quantify cerebral cell volume changes following chemically-induced anoxia/re-oxygenation

OBJECTIVE

The roles of individual types of cerebral cells in contributing to brain edema are undefined. The objective of this study was to determine the role of cerebral cell-column chromatography in quantifying cell volumes of individual cerebral cell lines, under chemically-induced anoxia/re-oxygenation (A/R).

METHODS

Cerebral endothelial cells (4 experiments) or type II astrocytes (4 experiments) were cultured to confluence on microcarrier beads. A chromatographic cell-column of 1.5 cm height was filled with non-treated cell-covered beads. The column was perfused at 1 ml/min with a balanced perfusate for one hour (Baseline). The perfusate was then switched to that containing 5 mM thioglycolic acid for one hour (Anoxia). Then the column was perfused with the normal perfusate for another two hours (Re-oxygenation). The total free space in the column, reversely reflecting cell volumes, was determined by averaged transit time (TTa) of a non-permeable flow tracer blue dextran. Decreased TTa means that cells swell, and vice versa.

RESULTS

TTa in endothelial cell columns increased with a peak at 60 minutes of re-oxygenation. TTa in astrocyte columns decreased with a nadir at 30 minutes of re-oxygenation.

CONCLUSION

Cell column chromatography can be used to determine the cerebral cell volume changes following chemically-induced anoxia/re-oxygenation.

Involvement of apolipoprotein E in glioblastoma: immunohistochemistry and clinical outcome

We hypothesised that apolipoprotein E (apoE) influences brain tumours by delivery of lipids to tumour cells and by analogy with other brain insults. APOE gene analysis was performed for 126 glioblastomas, the commonest primary brain tumour. Neither APOE epsilon2 nor epsilon4 alleles were significantly associated with differences in post-operative survival. However, there was apoE immunoreactivity of tumour cells, macrophages in areas of necrosis and astrocytes nearby. The immunohistochemistry findings support the hypothesis that apoE is involved in the delivery of lipids to tumour cells and in the recycling of lipids by macrophages in necrotic areas, raising the possibility that apoE-mediated lipid transport may represent a new therapeutic target in brain tumours.

Association between apolipoprotein E4 and rehabilitation outcome in hospitalized ischemic stroke patients

OBJECTIVE

To determine the value of apolipoprotein E4 (APOE*E4) allele in predicting discharge impairment and disability in ischemic stroke patients after acute rehabilitation.

DESIGN

Prospective study comparing results of rehabilitation in patients with different APOE genotypes.

SETTING

Acute neurologic rehabilitation department in Israel.

PARTICIPANTS

One hundred one consecutive patients 75 years old or less with a first ischemic stroke.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Impairment, as measured by the National Institutes of Health Stroke Scale (NIHSS), and disability, as assessed with the FIM trade mark instrument.

RESULTS

On admission, there was no significant difference in the FIM or NIHSS measurements between the apo E4 group and other patients, but the prevalence of aphasia was 2.07 times more frequent in those with the APOE*E4 genotype (95% confidence interval, 0.98-4.4). A logistic regression model demonstrated that score measurements on admission were highly predictive of the NIHSS score at discharge (receiver operator curve=96.1%), whereas the presence of the APOE*E4 genotype did not add significantly to the model in predicting poorer rehabilitation treatment outcome as measured by the FIM or the NIHSS.

CONCLUSIONS

The presence of the apo E4 allele did not predict a poorer outcome of rehabilitation treatment after ischemic stroke, but it was associated with an increased prevalence of aphasia. Further studies are warranted to confirm this association.

Genetic vulnerability following traumatic brain injury: the role of apolipoprotein E

Apolipoprotein E (APOE) is thought to be responsible for the transportation of lipids within the brain, maintaining structural integrity of the microtubule within the neurone, and assisting with neural transmission. Possession of the APOE epsilon4 allele has also been shown to influence neuropathological findings in patients who die from traumatic brain injury, including the accumulation of amyloid beta protein. Previous clinical studies reporting varying outcome severities of traumatic brain injury, including cognitive and functional recovery, all support the notion that APOE epsilon4 allele possession is associated with an unfavourable outcome. Evidence from experimental and clinical brain injury studies confirms that APOE plays an important role in the response of the brain to injury.

Edema after intracerebral hemorrhage: correlations with coagulation parameters and treatment

OBJECT

Development of edema is known to contribute to poor outcome after spontaneous intracerebral hemorrhage (ICH). Recent research has identified thrombin as a key mediator in the development of edema in animal models; however, little has been published correlating the coagulation cascade and edema in humans.

METHODS

In this retrospective clinical study of 80 patients with spontaneous supratentorial ICH, the authors sought to identify factors associated with edema development and outcome, including lesion imaging parameters, anticoagulant use, international normalized ratio and platelet count on hospital admission, and treatment with mannitol and steroid medications. A multivariate model was used to identify edema volume, use of mannitol, elevated blood glucose, and the presence of intraventricular hemorrhage as predictors of poor outcome at the time patients were discharged from the hospital. The authors developed a quadratic model for predicting edema volume against time by using a random coefficients model, and found that edema peaks between Days 5 and 6 after onset of ICH. The volume of the hemorrhage and the platelet count correlated significantly with edema volume within the first 24 hours post-ICH in the multiple regression analysis (p < 0.0001, r2 = 0.75). Edema growth during the first 5 days post-ICH also correlated with the platelet count, with an increasing platelet count associated with an increasing growth of edema (p = 0.0013).

CONCLUSIONS

The authors propose that factors released from activated platelets at the site of hemorrhage, for example vascular endothelial growth factor, may interact with thrombin to increase vascular permeability and contribute to the development of edema.

Effect of apolipoprotein E genotype on in-hospital mortality following intracerebral haemorrhage

OBJECTIVE

To determine the relationship between the apolipoprotein E (APOE) epsilon4 allele and in-hospital mortality from intracerebral haemorrhage (ICH).

MATERIAL AND METHODS

Patients admitted to two acute stroke units with ICH were prospectively evaluated and APOE genotyped. In-hospital survival was recorded in 176 patients.

RESULTS

There were 85 men and 91 women, mean age 68 years. Fifty-two (30%) of the 176 patients died in hospital. After adjusting for sex, age, hospital, and race, increased age (P = 0.009) and the presence of the APOEepsilon4 allele (P = 0.026) significantly reduced in-hospital survival.

CONCLUSION

The APOEepsilon4 allele in this population may be associated with poor survival following ICH.

Apolipoprotein E polymorphism and outcome after closed traumatic brain injury: influence of ethnic and regional differences

OBJECT

The presence of the apolipoprotein E-epsilon4 (APOE-epsilon4) allele is reported to be associated with poor outcome after traumatic brain injury (TBI). This study was performed to determine if the presence of the APOE-epsilon4 allele influenced outcome in a cohort of black patients with TBI who had homogeneous neuropathological findings.

METHODS

Venous blood was collected at the time of admission to determine the APOE genotype in black Zulu-speaking patients who presented with traumatic cerebral contusions. The frequency of the APOE-epsilon4 allele's appearance was correlated with outcome at a minimum of 6 months of follow up. Univariate and multivariate analyses were performed to determine independent risk factors and to control for confounding factors. In 110 black Zulu-speaking patients with traumatic cerebral contusions, genotypes for APOE were analyzed. Eleven of 45 (24.4%) with the APOE-epsilon4 allele experienced a poor outcome, compared with 10 (15.4%) of 65 without this allele (p = 0.34). Both patients with homozygous APOE-epsilon4 alleles experienced a good outcome (Glasgow Outcome Score 5). Univariate and multivariate analysis revealed no significant relationship in patients with the APOE-epsilon4 allele with regard to age, admission Glasgow Comas Scale score, contusion volume, type of neurosurgical management, and outcome. The risk of a poor outcome was, however, greater in patients with the APOE-epsilon4 allele (relative risk 1.59; 95% confidence interval 0.74-3.42).

CONCLUSIONS

The authors recorded no relationship between APOE-epsilon4 allele status and outcome after TBI in black patients. Given the high regional susceptibility to the APOE gene, further studies, possibly even community-based investigations and studies conducted in other geographic areas, are probably warranted.

Apolipoprotein E and intellectual achievement

OBJECTIVES

To determine whether apolipoprotein E (apo E) genotype influences intellectual achievement in cognitively normal individuals.

DESIGN

Between 1994 and 1999 we performed apo E testing on 1,000 self-described cognitively normal residents of Maricopa County and detailed neuropsychological testing on a subset of 250.

SETTING

Tertiary care academic medical center.

PARTICIPANTS

Cognitively normal adults genotyped for apo E.

MEASUREMENTS

Measures of intellectual background included years of education and a demographically based estimate of intellectual capacity (demographic intellectual quotient (DIQ)). Measures of intellectual achievement, which included Wechsler Adult Intelligence Scale revised (WAIS-R), information (WAISI), and vocabulary (WAISV) scores, occupational intellectual requirements (OIR), and census-derived estimates of household income, were compared between apo E genetic subgroups while adjusting for intellectual background and demographic variables.

RESULTS

WAISI, WAISV, OIR, and income correlated with age, sex, education, and DIQ, but after controlling for these variables there were no clinically significant differences between apo E-e4 homozygotes and noncarriers on any measure.

CONCLUSIONS

No clinically significant differences between genotypes were observed for the effects of education and DIQ on WAISI, WAISV, OIR, or income, although a larger sample size would be required to exclude smaller, clinically insignificant differences.

Effect of apolipoprotein E genotype on hematoma volume after trauma

OBJECT

The apolipoprotein E-epsilon4 (APOE-epsilon4) allele is associated with poor outcome after head injury and spontaneous intracerebral hemorrhage (SICH). The aims of this study were to determine if patients in whom one or more APOE-epsilon4 alleles are present are more likely to sustain intracranial mass lesions after head injury and to determine whether there is an isoform-specific effect on the size of the intracranial hematoma.

METHODS

The authors performed a computerized volumetric analysis of 142 hematomas visible on computerized tomography (CT) scans obtained in 129 patients. The APOE genotype was determined by subjecting buccal smear samples to polymerase chain reaction and restriction enzyme digestion. Allele frequencies were similar in head-injured patients with and without intracranial hematomas (p = 0.36). Univariate analysis revealed that in those patients with one or more APOE-epsilon4 alleles hematoma volume was greater (cube root-transformed values) than that found in patients without the APOE-epsilon4 allele (3.1 cm compared with 2.5 cm, p = 0.0039). The results of univariate analysis also suggested significant effects of patient age, injury severity (mild, moderate, or severe according to admission Glasgow Coma Scale scores) and hematoma location (extraaxial, intraaxial, or both) on hematoma volume. The mechanism of injury (assault, fall, or other) was marginally associated with hematoma volume (p = 0.052). Time from injury to CT scan, hypoxia, and hypotension had no significant effect on hematoma volume. The results of multiple linear regression analysis showed that the presence of an APOE-epsilon4 allele and an extraaxial hematoma location were independent predictors of hematoma volume, after adjusting for patient age, hours between injury and CT scan, injury severity, and injury mechanism.

CONCLUSIONS

Larger hematomas were found in head-injured patients with one or more APOE-epsilon4 alleles than in patients without the allele. This may contribute to the poorer outcomes observed in these patients.