Origins of Polynesian Pigs Revealed by Mitochondrial Whole Genome Ancient DNA.

Domestic pigs (Sus scrofa) were first transported to Polynesia through a series of long-distance voyages ultimately linked to the Neolithic expansion of Austronesian-speaking people out of Asia. The descendants of the founding pigs belong to a rare mtDNA group referred to as the "Pacific Clade" that may have originated in peninsular or island Southeast Asia. We report the first whole genome mtDNA from domestic pigs from any of the remote islands of the Pacific. In this brief report, we describe the close link we discovered between ancient mtDNA from archaeological specimens from across Polynesia and from that of modern pigs in northern peninsular Southeast Asia, specifically southern China's Yunnan Province. More complete mtDNA coverage in commensal animals is necessary to improve our picture of the settlement of Polynesia (ca. 2800-700 years before the present) and specify the route, or routes, that pigs took from northern peninsular Southeast Asia.

Maternal Relationships among Ancient and Modern Southern African Sheep: Newly Discovered Mitochondrial Haplogroups.

We investigated the genetic diversity and historic relationships among southern African sheep as well as the relationships between them and sheep outside the continent by sourcing both archaeological and modern sheep samples. Archaeological sheep samples derived from the site Die Kelders 1, near Cape Town, date to approximately 1500 years ago. The modern samples were taken as ear snips from Damara, Namaqua Afrikaner, and Ronderib Afrikaner sheep on a farm in Prieska in the Northern Cape. Illumina sequencing libraries were constructed for both ancient and modern specimens. Ancient specimens were enriched for the mitochondrial genome using an in-solution hybridization protocol and modern specimens were subjected to shotgun sequencing. Sequences were mapped to the Ovis aries reference genome, assigned to haplogroups and subhaplogroups, and used to calculate a phylogenetic tree using previously published, geographically dispersed mitochondrial genome sheep sequences. Genetic diversity statistics show that southern African sheep have lower diversity than sheep in other regions. Phylogenetic analysis reveals that many modern southern African sheep are likely descended from prehistoric indigenous sheep populations and not from sheep imported from Europe during the historic period.

Systematic Ancient DNA Species Identification Fails to Find Late Holocene Domesticated Cattle in Southern Africa.

Establishing robust temporal control of the arrival of domesticated stock and the associated husbandry skills and lifeways in Southern Africa remains frustrated by the osteological similarities between domestic stock and wild endemic fauna. We report the results of a systematic ancient DNA survey of appropriately sized bovid remains from Later Stone Age deposits in four South African archaeological sites. We show that none of the tested remains originated in domesticated cattle. The precise date of arrival of domestic cattle in the region awaits further study, although we also report new radiocarbon determinations which further refine the local chronology.

Carotid artery disease in post-stroke survivors and effects of enriched environment on stroke pathology in a mouse model of carotid artery stenosis.

AIMS: Carotid artery disease (CAD) is an important risk factor for stroke. We first evaluated CAD and stroke pathology in elderly post-stroke survivors. To simulate CAD, we assessed long-term consequences of bilateral common carotid artery stenosis (BCAS) in mice and exposed them to environmental enrichment (EE). METHODS: Histopathological methods were used to determine degrees of CAD (% area stenosis), brain infarct types, sizes and distribution in post-stroke survivors and BCAS mice. Adult male C57BL/6J mice after BCAS or sham surgery were randomly assigned to standard housing (Std) or limited (3 h) or full-time (Full) exposure to EE per day for 12 weeks. RESULTS: High frequencies of moderate carotid artery stenosis (51-75%) were evident in post-stroke survivors whereas those with severe CAD (>75% stenosis) exhibited greater numbers of cortical rather than subcortical infarcts and, were at higher risk of developing dementia. BCAS in mice reduced cerebral blood flow by 52% (P < 0.01) and thickened carotid artery walls, regardless of EE duration. Remarkably, the total and cortical infarcts declined by >50% in BCAS mice exposed to EE compared with BCAS-Std (P < 0.01). Frontal lobe and cortical strokes were associated with worsening working memory tested in a radial maze paradigm. Proteomic analysis revealed EE, both BCAS-3 h and BCAS-Full attenuated coagulation cascade factors including fibrinogen and von Willebrand factor, markers of blood-brain barrier damage. CONCLUSION: Small cortical and subcortical infarcts were evident in both post-stroke survivors with CAD and BCAS mice. Experimental evidence suggested that moderate exposure to EE is sufficient to reduce subsequent stroke lesions.

Ageing causes prominent neurovascular dysfunction associated with loss of astrocytic contacts and gliosis.

AIMS: Normal neurovascular coupling, mediated by the fine interplay and communication of cells within the neurovascular unit, is critical for maintaining normal brain activity and cognitive function. This study investigated whether, with advancing age there is disruption of neurovascular coupling and specific cellular components of the neurovascular unit, and whether the effects of increasing amyloid (a key feature of Alzheimer's disease) would exacerbate these changes. METHODS: Wild-type mice, in which amyloid deposition is absent, were compared to transgenic amyloid precursor protein (APP) littermates (TgSwDI) which develop age-dependent increases in amyloid. Baseline cerebral blood flow and responses to whisker stimulation were measured. Components of the neurovascular unit (astrocytes, end-feet, pericytes, microglia) were measured by immunohistochemistry. RESULTS: Neurovascular coupling was progressively impaired with increasing age (starting at 12 months) but was not further altered in TgSwDI mice. Aged mice showed reduced vascular pericyte coverage relative to young but this was not related to neurovascular function. Aged mice displayed significant reductions in astrocytic end-feet expression of aquaporin-4 on blood vessels compared to young mice, and a prominent increase in microglial proliferation which correlated with neurovascular function. CONCLUSIONS: Strategies aimed to restore the loss of astrocytic end feet contact and reduce gliosis may improve neurovascular coupling.

Complete Mitochondrial Genomes of New Zealand's First Dogs.

Dogs accompanied people in their migrations across the Pacific Ocean and ultimately reached New Zealand, which is the southern-most point of their oceanic distribution, around the beginning of the fourteenth century AD. Previous ancient DNA analyses of mitochondrial control region sequences indicated the New Zealand dog population included two lineages. We sequenced complete mitochondrial genomes of fourteen dogs from the colonisation era archaeological site of Wairau Bar and found five closely-related haplotypes. The limited number of mitochondrial lineages present at Wairau Bar suggests that the founding population may have comprised only a few dogs; or that the arriving dogs were closely related. For populations such as that at Wairau Bar, which stemmed from relatively recent migration events, control region sequences have insufficient power to address questions about population structure and founding events. Sequencing mitogenomes provided the opportunity to observe sufficient diversity to discriminate between individuals that would otherwise be assigned the same haplotype and to clarify their relationships with each other. Our results also support the proposition that at least one dispersal of dogs into the Pacific was via a south-western route through Indonesia.

The genetic diversity of the Nguni breed of African Cattle (Bos spp.): complete mitochondrial genomes of haplogroup T1.

Domesticated cattle were commonplace in northern Africa by about 7,000 years ago. Archaeological evidence, however, suggests they were not established in southern Africa until much later, no earlier than 2,000 years ago. Genetic reconstructions have started to shed light on the movement of African cattle, but efforts have been frustrated by a lack of data south of Ethiopia and the nature of the mitochondrial haplogroup T1 which is almost fixed across the continent. We sequenced 35 complete mitochondrial genomes from a South African herd of Nguni cattle, a breed historically associated with Bantu speaking farmers who were among the first to bring cattle to southern Africa. As expected, all individuals in the study were found to be members of haplogroup T1. Only half of the sub-haplogroups of T1 (T1a-T1f) are represented in our sample and the overwhelming majority (94%) in this study belong to subhaplogroup T1b. A previous study of African cattle found frequencies of T1b of 27% in Egypt and 69% in Ethiopia. These results are consistent with serial multiple founder effects significantly shaping the gene pool as cattle were moved from north to south across the continent. Interestingly, these mitochondrial data give no indication that the impacts of the founder effects were ameliorated by gene flow from recently introduced Indian cattle breeds.

Complete mitochondrial DNA genome sequences from the first New Zealanders.

The dispersal of modern humans across the globe began ~65,000 y ago when people first left Africa and culminated with the settlement of East Polynesia, which occurred in the last 1,000 y. With the arrival of Polynesian canoes only 750 y ago, Aotearoa/New Zealand became the last major landmass to be permanently settled by humans. We present here complete mitochondrial genome sequences of the likely founding population of Aotearoa/New Zealand recovered from the archaeological site of Wairau Bar. These data represent complete mitochondrial genome sequences from ancient Polynesian voyagers and provide insights into the genetic diversity of human populations in the Pacific at the time of the settlement of East Polynesia.

Setting the stage - building and working in an ancient DNA laboratory.

With the introduction of next generation high throughput sequencing in 2005 and the resulting revolution in genetics, ancient DNA research has rapidly developed from an interesting but marginal field within evolutionary biology into one that can contribute significantly to our understanding of evolution in general and the development of our own species in particular. While the amount of sequence data available from ancient human, other animal and plant remains has increased dramatically over the past five years, some key limitations of ancient DNA research remain. Most notably, reduction of contamination and the authentication of results are of utmost importance. A number of studies have addressed different aspects of sampling, DNA extraction and DNA manipulation in order to establish protocols that most efficiently generate reproducible and authentic results. As increasing numbers of researchers from different backgrounds become interested in using ancient DNA technology to address key questions, the need for practical guidelines on how to construct and use an ancient DNA facility arises. The aim of this article is therefore to provide practical tips for building a state-of-the-art ancient DNA facility. It is intended to help researchers new to the field of ancient DNA research generally, and those considering the application of next generation sequencing, in their planning process.

Neuroprotective effect of adenoviral-mediated gene transfer of TIMP-1 and -2 in ischemic brain injury.

Gene therapy may be a promising approach for treatment of brain ischemia. We and others previously demonstrated that increased activity of matrix metalloproteinases (MMPs) contributes to the tissue damage that results from ischemic injury. The proteolysis of MMPs is tightly controlled by tissue inhibitors of MMPs (TIMPs). In this study, we examined whether adenoviral-mediated gene transfer of TIMP-1 and TIMP-2 could protect against neuronal damage induced by global cerebral ischemia in mice. An adenovirus expressing TIMP-1 or TIMP-2 (AdTIMP-1 or AdTIMP-2) or a control adenovirus (RAd60) or vehicle was injected into the striatum 3 days before transient global cerebral ischemia. The extent of neuronal damage was quantified 3 days post-ischemia. There was no significant difference in the extent of neuronal damage in vehicle as compared to RAd60-treated mice. In contrast, neuronal damage was reduced, by approximately 50%, after gene transfer of AdTIMP-1 (P<0.001) and AdTIMP-2 (P< 0.01) as compared to controls. This study provides the first in vivo evidence of the protective effects of TIMP-1 and TIMP-2 via gene transfer in global ischemia.

Neuroprotection by a selective estrogen receptor beta agonist in a mouse model of global ischemia.

The present study employs selective estrogen receptor (ER) agonists to determine whether 17beta-estradiol-induced neuroprotection in global ischemia is receptor mediated and, if so, which subtype of receptor (ERalpha or ERbeta) is predominantly responsible. Halothane-anesthetized female C57Bl/6J mice were ovariectomized, and osmotic minipumps containing ERbeta agonist diarylpropiolnitrile (DPN) (8 mg.kg(-1).day(-1), n = 12) or vehicle (50% DMSO in 0.9% saline) (n = 9) or ERalpha agonist propyl pyrazole triol (PPT) (2 mg.kg(-1).day(-1), n = 13) or vehicle (50% DMSO in 0.9% saline) (n = 10) were implanted subcutaneously. One week later transient global ischemia was induced by bilateral carotid artery occlusion under halothane anesthesia, and the mice were perfusion fixed 72 h later. ERbeta agonist DPN significantly reduced ischemic damage by 70% in the caudate nucleus and 55% in the CA1 region compared with vehicle controls (P < 0.05, Mann-Whitney U-statistic). In contrast, pretreatment with the ERalpha agonist PPT had no effect on the extent of neuronal damage compared with controls. The data indicate a significant estrogen receptor-mediated neuroprotection in a global cerebral ischemia model involving ERbeta.

Ancient DNA in anthropology: methods, applications, and ethics.

Anthropologists were quick to recognize the potential of new techniques in molecular biology to provide additional lines of evidence on questions long investigated in anthropology, as well as those questions that, while always of interest, could not have been addressed by more traditional techniques. The earliest ancient DNA studies, both within anthropology and in other fields, lacked rigorous hypothesis testing. However, more recently the true value of ancient DNA studies is being realized, and methods are being applied to a wide variety of anthropological questions. We review the most common methods and applications to date, and describe promising avenues of future research. We find that ancient DNA analyses have a valuable place in the array of anthropological techniques, but argue that such studies must not be undertaken merely to demonstrate that surviving DNA is present in organic remains, and that no such work should be performed before a careful consideration of the possible ethical ramifications of the research is undertaken.

Minimal ischaemic neuronal damage and HSP70 expression in MF1 strain mice following bilateral common carotid artery occlusion.

Investigation into the influence of specific genes and gene products upon the pathophysiology of cerebral ischaemia has been greatly enhanced by the use of genetically modified mice. A simple model of global cerebral ischaemia in mouse is bilateral common carotid artery occlusion (BCCAo) and the neuropathological impact of BCCAo has been investigated in several mouse strains. Bilateral carotid occlusion produces extensive neuronal damage in C57Bl/6J strain mice and this damage is linked to posterior communicating artery (PcomA) hypoplasticity in the circle of Willis. In the present study, we investigated the effect of BCCAo in MF1 strain mice and compared them with C57Bl/6J mice. The neuropathological consequences of BCCAo were assessed using standard histochemical staining and heat shock protein 70 (HSP70) immunohistochemical staining (to demarcate cells that had been ischaemically stressed). The effect of BCCAo on mean arterial blood pressure (MABP) was also measured. The plasticity of the circle of Willis was recorded using carbon black perfusion. MF1 mice displayed significantly less ischaemic neuronal damage and HSP70 immunoreactivity compared to C57Bl/6J mice following 10-20 min BCCAo. Moreover, ischaemic neuronal damage and HSP70 immunoreactivity in MF1 mice subjected to extended BCCAo (25-45 min) was never as extensive or widespread as that observed in C57Bl/6J mice after 20 min BCCAo. MABP in MF1 mice (102+/-5 mmHg) was significantly higher than in C57Bl/6J mice (87+/-5) during 20 min BCCAo. MABP in MF1 mice during 20 and 40 min (103+/-12 mmHg) BCCAo remained above pre-occlusion values for the entire occlusion period. MF1 mice had significantly greater circle of Willis plasticity (more PcomAs) than C57Bl/6J mice did. These data indicate that MF1 mice are less susceptible to BCCAo than C57Bl/6J mice and that this could be due to maintained increases in MABP during BCCAo and the lower prevalence of abnormalities of the circle of Willis in MF1 mice.

4-Hydroxynonenal immunoreactivity is increased in human hippocampus after global ischemia.

Oxidative stress and lipid peroxidation may contribute to the pathology of neurodegenerative disorders such as Alzheimer's disease (AD) and cerebral ischemia. 4-Hydroxynonenal (4-HNE) is a toxic by-product of lipid peroxidation, and immunoreactivity to 4-HNE has been used to examine lipid peroxidation in the pathogenesis of AD and ischemia. This study sought to determine 1) if there are cellular alterations in 4-HNE immunoreactivity in the human hippocampus after global ischemia, and 2) whether possession of an apolipoprotein E (APOE) epsilon4 allele influenced the extent of 4-HNE immunoreactivity. 4-HNE immunoreactivity was assessed semi-quantitatively in the temporal lobe of a group of controls (n = 44) and in a group of patients who had an episode of global ischemia as a result of a cardiorespiratory arrest and subsequently died (n = 56, survival ranged from 1hr to 42 days). There was minimal cellular 4-HNE immunoreactivity in the control group. However, compared to controls, 4-HNE immunoreactivity was significantly increased in neurons (p < 0.0002) and glia (p < 0.0001) in the hippocampal formation after global ischemia. Possession of an APOE epsilon4 allele did not influence the extent of neuronal or glial 4-HNE immunostaining in the control or global ischemia group. There was a significant negative correlation between the extent of neuronal 4-HNE immunoreactivity with survival period after global ischemia (r2 = 0.0801; p < 0.036) and a significant positive correlation between the extent of glial 4-HNE immunoreactivity and survival after global ischemia (r2 = 0.2958; p < 0.0001). The data indicate a marked increase in neuronal and glial 4-HNE. This substantiates a role for lipid peroxidation in the pathogenesis of cerebral ischemia. There was no indication that APOE genotype influenced the extent of 4-HNE immunoreactivity.

Targeting expression of hsp70i to discrete neuronal populations using the Lmo-1 promoter: assessment of the neuroprotective effects of hsp70i in vivo and in vitro.

Transgenic technology provides a powerful means of studying gene regulation and specific gene function with complex mammalian systems. In this study, the authors exploited the specific and discrete neuronal expression pattern mediated by promoter 1 of the Lmo-1 gene to study the neuroprotective effects of the inducible form of heat shock protein 70kD (hsp70i) in primary hippocampal cultures in a mouse model of global cerebral ischemia. Targeting expression of hsp70i to hippocampal neurons protected these cells significantly from toxic levels of glutamate and oxidative stress (for example, exposure to 10 micromol/L free iron produced a 26% increase in lactate dehydrogenase release from neurons cultured from wild-type mice, but a 7% increase in neurons cultured from hsp70i transgenic mice). Bilateral carotid occlusion (25 minutes) produced significantly less neuronal damage in the caudate nucleus and posterior thalamus in hsp70i transgenic mice than in wild-type littermates (for example, 21% +/- 9.3% and 12.5% +/- 9.0% neuronal damage in lateral caudate nucleus of wild-type and hsp70i transgenic mice, respectively, P < 0.05). The current study highlights the utility of targeted expression of transgenes of interest in cerebral ischemia and demonstrates that expression of hsp70i alone is sufficient to mediate the protection of primary neurons from denaturing stress and that expression of human hsp70i in vivo plays crucial role in determining the fate of neurons after ischemic challenge.

Impaired neuronal plasticity in transgenic mice expressing human apolipoprotein E4 compared to E3 in a model of entorhinal cortex lesion.

The apolipoprotein E (APOE) epsilon 4 allele is a major risk factor for late-onset familial and sporadic Alzheimer's disease (AD) and is associated with a poor outcome after brain injury. Each apoE isoform is suggested to have differential effects on neuronal repair mechanisms within the CNS. In the present study, APOE genotype influence on the immediate response to injury and subsequent repair process was examined in a line of transgenic APOE mice possessing human APOE gene insertions (epsilon 3 and epsilon 4). Quantification of synaptophysin and GAP-43 immunoreactivity was used to measure the extent of degeneration and regeneration after entorhinal cortex lesion (ECL). Progressive neurodegenerative decline occurred in the ipsilateral dentate gyrus until day 28 post-ECL which was more severe in APOE epsilon 3 mice compared to APOE epsilon 4 mice. By day 90 post-ECL compensatory sprouting and reactive synaptogenesis had taken place in the dentate gyrus of APOE epsilon 3 mice such that GAP-43 and synaptophysin immunoreactivity had returned to prelesion levels. In contrast, APOE epsilon 4 mice displayed significant deficits in synaptophysin and GAP-43 immunostaining compared to the APOE epsilon 3 mice (P < 0.05). Expansion of the inner molecular layer (IML) was used as a measure of the sprouting index from the commissural-associational pathway and by day 90 post-ECL the IML width in APOE epsilon 3 mice had increased by 45% but only 20% in APOE epsilon 4 mice (P < 0.0001). ApoE immunoreactivity was increased within the neuropil and glia to the same extent in APOE epsilon 3 and APOE epsilon 4 mice post-ECL. There was no significant difference in the deposition and clearance of degeneration products between APOE epsilon 3 and epsilon 4 mice post-ECL. These results indicate that neuronal plasticity is impaired in transgenic mice possessing human APOE epsilon 4 alleles compared to APOE epsilon 3. These isoform-specific differences in plasticity may relate to the severity of AD and poor, long-term recovery after head injury in APOE epsilon 4 individuals.

Alterations in ApoE and ApoJ in relation to degeneration and regeneration in a mouse model of entorhinal cortex lesion.

Apolipoproteins are primarily involved in the transport of lipid and cholesterol within the central nervous system (CNS) and are thought to play a role in synaptic remodeling, repair, and regeneration after brain injury. In the present study, alterations in apolipoproteins E (apoE) and J (apoJ) were examined in the molecular layers of the dentate gyrus after unilateral chemical lesioning of the entorhinal cortex (ECL), at days 0, 1, 3, 7, 28, and 90 days following injury. Alterations in immunostaining for these proteins were assessed in relation to accumulation of silver-labeled degeneration products and alterations in synaptophysin and GAP-43 immunoreactivity. Quantitative analysis of synaptophysin and GAP-43 immunostaining highlighted synaptic loss and fiber degeneration initially (3-7 days post-ECL), with subsequent terminal sprouting and reactive synaptogenesis occurring at longer survival periods (28-90 days post-ECL). Increased apoE and apoJ immunoreactivity was evident first within the neuropil (*P < 0.05 and **P < 0.01) followed by intense glial staining by day 7 post-ECL. By day 28 apoE and apoJ immunostaining had returned almost to baseline levels. However, at day 90 post-ECL, neuropil apoE and apoJ immunoreactivity was dramatically increased compared to contralateral levels (**P < 0.01 and ***P < 0.0001, respectively). Silver-labeled degeneration products were found to be in abundance at day 3 postlesion; however, by day 7 this was reduced leaving only a thin band of material within the MML and at day 90 post-ECL, dentate silver staining was similar to that of controls. The results indicate that apoE and apoJ are upregulated after injury and parallel clearance of cholesterol and lipid debris from the site of injury. This coordinated alteration in apolipoproteins may redistribute lipid material to sprouting fibers to promote neurite extension and may play an important role in long-term plasticity changes following injury.

Increased neuronal damage and apoE immunoreactivity in human apolipoprotein E, E4 isoform-specific, transgenic mice after global cerebral ischaemia.

Apolipoprotein E (apoE, protein; APOE, gene) is expressed as three isoforms in humans (E2, E3, E4). The APOE-epsilon4 allele is associated with a poor outcome in patients after head injury of which ischaemic brain damage is a contributor of mortality and morbidity. The aim of the study was to determine whether mice expressing human APOE-epsilon4 displayed more extensive ischaemic neuronal damage 72 h after transient global ischaemia compared with mice which express human APOE-epsilon3. APOE-epsilon3 and -epsilon4 transgenic mice, under the control of a human promoter, were used which express human APOE in neurons and glia. Ischaemic neuronal damage in the CA1 pyramidal cell layer in the APOE-epsilon4 transgenic mice was significantly greater than in the APOE-epsilon3 mice after global ischaemia (36.4+/-8.9%, 18.2+/-7.3%; P<0.05). This was associated with more extensive neuronal apoE immunoreactivity in the CA1 pyramidal cell layer in the APOE-epsilon4 transgenic mice compared with APOE-epsilon3 transgenic mice. In contrast, in the caudate nucleus, there were similar levels of ischaemic neuronal damage in the APOE-epsilon3 and -epsilon4 transgenic mice (39.2 +/-10.1%; 44.6+/-8.4%, P = 0.32). In the caudate, similar numbers of neurons were immunostained for apoE in the APOE-epsilon3 and -epsilon4 transgenic mice. The present study demonstrated that the APOE-epsilon4 allele is associated with an increased vulnerability of a specific brain region to the effects of global ischaemia, which is closely associated with an increase in neuronal apoE. The data extend previous work and are consistent with an association of the APOE-epsilon4 allele with a poor outcome after acute brain injury in humans.

beta-amyloid (Abeta)42(43), abeta42, abeta40 and apoE immunostaining of plaques in fatal head injury.

beta-Amyloid (Abeta) deposits are found in the brains of approximately one-third of patients who die within days after a severe head injury; their presence correlating strongly with possession of an apolipoprotein E (apoE)-epsilon4 allele. The aim of the study was to investigate the relationship between Abeta42, Abeta40 and apoE immunostaining of Abeta plaques in the cerebral cortex and the relevance of apoE genotype in 23 fatally head-injured patients. These cases were known to have Abeta deposits from a previous study in which they were examined and semiquantified and related to apoE genotype. In the present study, the temporal cortex was probed using four different antibodies that recognize Abeta42(43), Abeta40 and an antibody to apoE. Abeta42(43)-positive plaques were observed in all of the 23 cases and Abeta40 immunoreactivity in only 11 of the 23 cases. In addition, semiquantitative analysis showed that relatively fewer plaques were detected with anti-Abeta40 than anti-Abeta42(43). ApoE-immunoreactive plaques were identified in 18 of the 23 cases. The number of plaques stained for apoE was relatively less than for Abeta42(43) but greater than for Abeta40. Furthermore, the density of Abeta plaques detected using either Abeta42(43), Abeta40 or apoE antibodies was associated with possession of apoE-epsilon4 in an allele dose-dependent manner. The results are consistent with Abeta42(43) as the initially deposited species in brain parenchyma and provide evidence that apoE is involved in the early stages of amyloid deposition. Further, the findings may be of relevance to the role of apoE genotype in influencing outcome after acute brain injury.

The role of apolipoprotein E in Alzheimer's disease, acute brain injury and cerebrovascular disease: evidence of common mechanisms and utility of animal models.

The epsilon 4 allele of apolipoprotein E (APOE denotes gene; apoE denotes protein) is a major risk factor for Alzheimer's disease (AD). More recent evidence indicates an association with a poor outcome after acute brain injury including that due to head trauma and intracerebral hemorrhage. APOE gene polymorphism also influences the risk of hemorrhage in cerebral amyloid angiopathy. These diverse brain disorders seem to have some mechanisms in common. The multiplicity of the roles of apoE within the central nervous system is currently being unraveled. For example, apoE can interact with amyloid beta-protein and tau, proteins central to the pathogenesis of AD. In addition to these effects, it is proposed that one of the major functions of apoE is to mediate neuronal protection, repair and remodeling. In all of the different roles proposed, there are marked apoE-isoform specific differences. Although it remains to be clarified which is the most important mechanism(s) in each disorder in which apoE is involved, these isoform specific differences seem to underly a genetically determined susceptibility to outcome from acute brain injury and to AD with APOE epsilon 4 conferring relative vulnerability. This review focuses on apoE research, from clinical studies to animal models, in AD, acute brain injury and cerebrovascular disease and explores the common mechanisms that may explain some of the complex underlying neurobiology.