Multivariate analyses of peripheral blood leukocyte transcripts distinguish Alzheimer's, Parkinson's, control, and those at risk for developing Alzheimer's.

The need for a reliable, simple, and inexpensive blood test for Alzheimer's disease (AD) suitable for use in a primary care setting is widely recognized. This has led to a large number of publications describing blood tests for AD, which have, for the most part, not been replicable. We have chosen to examine transcripts expressed by the cellular, leukocyte compartment of blood. We have used hypothesis-based cDNA arrays and quantitative PCR to quantify the expression of selected sets of genes followed by multivariate analyses in multiple independent samples. Rather than a single study with no replicates, we chose an experimental design in which there were multiple replicates using different platforms and different sample populations. We have divided 177 blood samples and 27 brain samples into multiple replicates to demonstrate the ability to distinguish early clinical AD (Clinical Dementia Rating scale 0.5), Parkinson's disease (PD), and cognitively unimpaired APOE4 homozygotes, as well as to determine persons at risk for future cognitive impairment with significant accuracy. We assess our methods in a training/test set and also show that the variables we use distinguish AD, PD, and control brain. Importantly, we describe the variability of the weights assigned to individual transcripts in multivariate analyses in repeated studies and suggest that the variability we describe may be the cause of inability to repeat many earlier studies. Our data constitute a proof of principle that multivariate analysis of the transcriptome related to cell stress and inflammation of peripheral blood leukocytes has significant potential as a minimally invasive and inexpensive diagnostic tool for diagnosis and early detection of risk for AD.

Purification and characterization of a hemocyanin (Hemo1) with potential lignin-modification activities from the wood-feeding termite, Coptotermes formosanus Shiraki.

Coptotermes formosanus Shiraki is a well-known wood-feeding termite, which can degrade not only cellulose and hemicellulose polysaccharides, but also some aromatic lignin polymers with its enzyme complex to the woody biomass. In this study, a very abundant protein was discovered and purified, using a three-step column chromatography procedure, from the tissue homogenate of the salivary glands and the gut of C. formosanus. Mass spectrometric analysis and the following peptide searching against the mRNA database toward this termite species indicated that the novel protein was a hemocyanin enzyme, termed as Hemo1, which further exhibited a strong oxidase activity in the substrate bioassays toward ABTS [2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)], as well as other aromatic analogues, such as catechol and veratryl alcohols. This oxidative protein was an acid-favored enzyme with a molecular weight at 82 kDa, and highly active at 80 °C. These findings indicated that the novel protein, hemocyanin, discovered from the gut system of C. formosanus, might be an important ligninolytic enzyme involved in the biomass pretreatment processing, which will potentially enhance the digestibility and utilization of biomass polysaccharides in termite digestive systems.

Activated protein C analog protects from ischemic stroke and extends the therapeutic window of tissue-type plasminogen activator in aged female mice and hypertensive rats.

BACKGROUND AND PURPOSE: 3K3A-activated protein C (APC) protects young, healthy male rodents after ischemic stroke. 3K3A-APC is currently under development as a neuroprotectant for acute ischemic stroke in humans. Stroke Therapy Academic Industry Roundtable recommends that after initial studies in young, healthy male animals, further studies should be performed in females, aged animals, and animals with comorbid conditions. Here, we studied the effects of delayed 3KA-APC therapy alone and with tissue-type plasminogen activator (tPA) in aged female mice and spontaneously hypertensive rats. METHODS: We used Stroke Therapy Academic Industry Roundtable recommendations for ensuring good scientific inquiry. Murine recombinant 3K3A-APC (0.2 mg/kg) alone or with recombinant tPA (10 mg/kg) was given intravenously 4 hours after transient middle cerebral artery occlusion in aged female mice and rats and after embolic stroke in spontaneously hypertensive rat. 3K3A-APC was additionally administered within 3 to 7 days after stroke. The neuropathological analysis and neurological scores, foot-fault, forelimb asymmetry, and adhesive removal tests were performed within 7 and 28 days of stroke. RESULTS: In all models, tPA alone had no effects on the infarct volume or behavior. 3K3A-APC alone or with tPA reduced the infarct volume 7 days after the middle cerebral artery occlusion in aged female mice and embolic stroke in spontaneously hypertensive rat by 62% to 66% and 50% to 53%, respectively, significantly improved (P<0.05) behavior, and eliminated tPA-induced intracerebral microhemorrhages. In aged female mice, 3K3A-APC was protective within 4 weeks of stroke. CONCLUSIONS: 3K3A-APC protects from ischemic stroke and extends the therapeutic window of tPA in aged female mice and in spontaneously hypertensive rat with a comorbid condition.

An activated protein C analog stimulates neuronal production by human neural progenitor cells via a PAR1-PAR3-S1PR1-Akt pathway.

Activated protein C (APC) is a protease with anticoagulant and cell-signaling activities. In the CNS, APC and its analogs with reduced anticoagulant activity but preserved cell signaling activities, such as 3K3A-APC, exert neuroprotective, vasculoprotective, and anti-inflammatory effects. Murine APC promotes subependymal neurogenesis in rodents in vivo after ischemic and traumatic brain injury. Whether human APC can influence neuronal production from resident progenitor cells in humans is unknown. Here we show that 3K3A-APC, but not S360A-APC (an enzymatically inactive analog of APC), stimulates neuronal mitogenesis and differentiation from fetal human neural stem and progenitor cells (NPCs). The effects of 3K3A-APC on proliferation and differentiation were comparable to those obtained with fibroblast growth factor and brain-derived growth factor, respectively. Its promoting effect on neuronal differentiation was accompanied by inhibition of astroglial differentiation. In addition, 3K3A-APC exerted modest anti-apoptotic effects during neuronal production. These effects appeared to be mediated through specific protease activated receptors (PARs) and sphingosine-1-phosphate receptors (S1PRs), in that siRNA-mediated inhibition of PARs 1-4 and S1PRs 1-5 revealed that PAR1, PAR3, and S1PR1 are required for the neurogenic effects of 3K3A-APC. 3K3A-APC activated Akt, a downstream target of S1PR1, which was inhibited by S1PR1, PAR1, and PAR3 silencing. Adenoviral transduction of NPCs with a kinase-defective Akt mutant abolished the effects of 3K3A-APC on NPCs, confirming a key role of Akt activation in 3K3A-APC-mediated neurogenesis. Therefore, APC and its pharmacological analogs, by influencing PAR and S1PR signals in resident neural progenitor cells, may be potent modulators of both development and repair in the human CNS.

A lipoprotein receptor cluster IV mutant preferentially binds amyloid-ß and regulates its clearance from the mouse brain.

Soluble low density lipoprotein receptor-related protein-1 (sLRP1) binds ~70% of amyloid ß-peptide (Aß) in human plasma. In Alzheimer disease (AD) and individuals with mild cognitive impairment converting to AD, plasma sLRP1 levels are reduced and sLRP1 is oxidized, which results in diminished Aß peripheral binding and higher levels of free Aß in plasma. Experimental studies have shown that free circulating Aß re-enters the brain and that sLRP1 and/or its recombinant wild type cluster IV (WT-LRPIV) prevent Aß from entering the brain. Treatment of Alzheimer APPsw(+/0) mice with WT-LRPIV has been shown to reduce brain Aß pathology. In addition to Aß, LRPIV binds multiple ligands. To enhance LRPIV binding for Aß relative to other LRP1 ligands, we generated a library of LRPIV-derived fragments and full-length LRPIV variants with glycine replacing aspartic acid residues 3394, 3556, and 3674 in the calcium binding sites. Compared with WT-LRPIV, a lead LRPIV-D3674G mutant had 1.6- and 2.7-fold higher binding affinity for Aß40 and Aß42 in vitro, respectively, and a lower binding affinity for other LRP1 ligands (e.g. apolipoprotein E2, E3, and E4 (1.3-1.8-fold), tissue plasminogen activator (2.7-fold), matrix metalloproteinase-9 (4.1-fold), and Factor Xa (3.8-fold)). LRPIV-D3674G cleared mouse endogenous brain Aß40 and Aß42 25-27% better than WT-LRPIV. A 3-month subcutaneous treatment of APPsw(+/0) mice with LRPIV-D3674G (40 µg/kg/day) reduced Aß40 and Αß42 levels in the hippocampus, cortex, and cerebrospinal fluid by 60-80% and improved cerebral blood flow responses and hippocampal function at 9 months of age. Thus, LRPIV-D3674G is an efficient new Aß clearance therapy.

Activated protein C analog promotes neurogenesis and improves neurological outcome after focal ischemic stroke in mice via protease activated receptor 1.

3K3A-APC is a recombinant analog of activated protein C (APC) which is an endogenous protease with multiple functions in the body. Compared to APC, 3K3A-APC has reduced anticoagulant activity but preserved cell signaling activities. In the brain, 3K3A-APC exerts neuroprotective effects after an acute or chronic injury. 3K3A-APC is currently under clinical assessment as a neuroprotective agent following acute ischemic stroke. Whether 3K3A-APC can influence post-ischemic neurogenesis and improve neurological outcome by promoting brain repair remains unknown. Here we show that murine 3K3A-APC 0.8mg/kg intraperitoneally given at 12h, 1, 3, 5 and 7 days after permanent distal middle cerebral artery occlusion (dMCAO) in mice compared to vehicle improves significantly sensorimotor and locomotor activity 7 and 14 days after stroke, reduces infarct and edema volumes 7 days after stroke by 43% (P<0.05) and 50% (P<0.05), respectively, increases the number of newly formed neuroblasts in the subventricular zone, corpus callosum and the peri-infarct area 7 days after stroke by 2.2-fold, 2.3-fold and 2.2-fold (P<0.05), respectively, and increases the cortical width index 14 days after stroke by 28% (P<0.05). Functional outcome in 3K3A-APC-treated group, but not in vehicle-treated group, correlated inversely with the reductions in the infarct volume, and positively with the number of neuroblasts migrating in the peri-infarct area and the cortical width index. The effects of 3K3A-APC on neuroprotection, neurogenesis and brain repair were lost in protease activated receptor 1 (PAR1) deficient mice. Thus, late therapy with 3K3A-APC is neuroprotective and promotes stroke-induced neurogenesis and repair through PAR1 in mice.

An activated protein C analog with reduced anticoagulant activity extends the therapeutic window of tissue plasminogen activator for ischemic stroke in rodents.

BACKGROUND AND PURPOSE: Tissue plasminogen activator (tPA) is the only approved therapy for acute ischemic stroke. However, tPA has a brief therapeutic window. Its side effects include intracerebral bleeding and neurotoxicity. Therefore, a combination therapy with tPA and agents that can extend the therapeutic window of tPA and/or counteract its side effects are warranted. Here, we studied whether 3K3A-APC, a neuroprotective analog of activated protein C with reduced anticoagulant activity, can enhance the therapeutic effects of tPA in models of ischemic stroke in rodents. METHODS: Human recombinant tPA (10 mg/kg), alone or in combination with human recombinant 3K3A-APC (2 mg/kg), was administered intravenously 4 hours after proximal or distal transient middle cerebral artery occlusion in mice and embolic stroke in rats. The 3K3A-APC was additionally administered for 3 to 4 consecutive days after stroke. The neuropathological and neurological analyses were performed at 1 to 7 days after stroke. RESULTS: In all models, tPA alone had no effects on the infarct volume or behavior (ie, neurological score, foot-fault, forelimb asymmetry, adhesive removal) compared with vehicle. The tPA and 3K3A-APC combination therapy reduced the infarct volume 24 hours and 7 days after proximal or distal transient middle cerebral artery occlusion in mice and 7 days after embolic stroke in rats by 65%, 63%, and 52%, respectively, significantly (P<0.05) improved behavior and eliminated tPA-induced intracerebral microhemorrhages. CONCLUSIONS: The 3K3A-APC extends the therapeutic window of tPA for ischemic stroke in rodents. Therefore, this combination therapy also should be considered for treating stroke in humans.

Activated protein C analog with reduced anticoagulant activity improves functional recovery and reduces bleeding risk following controlled cortical impact.

The anticoagulant activated protein C (APC) protects neurons and vascular cells from injury through its direct cytoprotective effects that are independent of its anticoagulant action. Wild-type recombinant murine APC (wt-APC) exerts significant neuroprotection in mice if administered early after traumatic brain injury (TBI). Here, we compared efficacy and safety of a late therapy for TBI with wt-APC and 3K3A-APC, an APC analog with approximately 80% reduced anticoagulant activity but normal cytoprotective activity, using a controlled cortical impact model of TBI. Mice received 0.8 mg/kg intraperitoneally of recombinant murine 3K3A-APC, wt-APC or saline at 6, 12, 24 and 48 h after injury. 3K3A-APC (n=15) relative to wt-APC (n=15) improved motor and sensorimotor recovery within the first three days post-trauma as demonstrated by rotarod (p<0.05) and beam balance test (p<0.05), respectively. Both, wt-APC and 3K3A-APC reduced the lesion volume seven days after injury by 36% (n=8; p<0.01) and 56% (n=8; p<0.01), respectively, compared to saline (n=8). Three days post-TBI, the hemoglobin levels in the injured brain were increased by approximately 3-fold after wt-APC treatment compared to saline indicating an increased risk for intracerebral bleeding. In contrast, comparable levels of brain hemoglobin in 3K3A-APC-treated and saline-treated mice suggested that 3K3A-APC treatment did not increase risk for bleeding after TBI. Thus, compared to wt-APC, 3K3A-APC is more efficacious and safer therapy for TBI with no risk for intracerebral hemorrhage.

Activated protein C therapy slows ALS-like disease in mice by transcriptionally inhibiting SOD1 in motor neurons and microglia cells.

Activated protein C (APC) is a signaling protease with anticoagulant activity. Here, we have used mice expressing a mutation in superoxide dismutase-1 (SOD1) that is linked to amyotrophic lateral sclerosis (ALS) to show that administration of APC or APC analogs with reduced anticoagulant activity after disease onset slows disease progression and extends survival. A proteolytically inactive form of APC with reduced anticoagulant activity provided no benefit. APC crossed the blood-spinal cord barrier in mice via endothelial protein C receptor. When administered after disease onset, APC eliminated leakage of hemoglobin-derived products across the blood-spinal cord barrier and delayed microglial activation. In microvessels, motor neurons, and microglial cells from SOD1-mutant mice and in cultured neuronal cells, APC transcriptionally downregulated SOD1. Inhibition of SOD1 synthesis in neuronal cells by APC required protease-activated receptor-1 (PAR1) and PAR3, which inhibited nuclear transport of the Sp1 transcription factor. Diminished mutant SOD1 synthesis by selective gene excision within endothelial cells did not alter disease progression, which suggests that diminished mutant SOD1 synthesis in other cells, including motor neurons and microglia, caused the APC-mediated slowing of disease. The delayed disease progression in mice after APC administration suggests that this approach may be of benefit to patients with familial, and possibly sporadic, ALS.

Neuroprotective activities of activated protein C mutant with reduced anticoagulant activity.

The anticoagulant activated protein C (APC) protects neurons and endothelium via protease activated receptor (PAR)1, PAR3 and endothelial protein C receptor. APC is neuroprotective in stroke models. Bleeding complications may limit the pharmacologic utility of APC. Here, we compared the 3K3A-APC mutant with 80% reduced anticoagulant activity and wild-type (wt)-APC. Murine 3K3A-APC compared with wt-APC protected mouse cortical neurons from N-methyl-D-aspartate-induced apoptosis with twofold greater efficacy and more potently reduced N-methyl-D-aspartate excitotoxic lesions in vivo. Human 3K3A-APC protected human brain endothelial cells (BECs) from oxygen/glucose deprivation with 1.7-fold greater efficacy than wt-APC. 3K3A-APC neuronal protection required PAR1 and PAR3, as shown by using PAR-specific blocking antibodies and PAR1- and PAR3-deficient cells and mice. BEC protection required endothelial protein C receptor and PAR1. In neurons and BECs, 3K3A-APC blocked caspase-9 and -3 activation and induction of p53, and decreased the Bax/Bcl-2 pro-apoptotic ratio. After distal middle cerebral artery occlusion (dMCAO) in mice, murine 3K3A-APC compared with vehicle given 4:00 h after dMCAO improved the functional outcome and reduced the infarction volume by 50% within 3 days. 3K3A-APC compared with wt-APC multi-dosing therapy at 12:00 h, 1, 3, 5 and 7 days after dMCAO significantly improved functional recovery and reduced the infarction volume by 75% and 38%, respectively, within 7 days. The wt-APC, but not 3K3A-APC, significantly increased the risk of intracerebral bleeding as indicated by a 50% increase in hemoglobin levels in the ischemic hemisphere. Thus, 3K3A-APC offers a new approach for safer and more efficacious treatments of neurodegenerative disorders and stroke with APC.

Species-dependent neuroprotection by activated protein C mutants with reduced anticoagulant activity.

Activated protein C (APC) is a protease with anticoagulant and cytoprotective activities. APC is neuroprotective in rodent models of stroke. But, an APC variant with reduced anticoagulant activity, 3K3A-APC, compared to wild-type APC shows greater neuroprotection with no risk for bleeding in stroke models. To determine whether 3K3A-APC exhibits species-dependent neuroprotection similar to that as seen with wild-type APC, we studied murine and human recombinant 3K3A-APC mutants which show approximately 80% reduced anticoagulant activity. Murine 3K3A-APC (0.2 mg/kg i.v.) administered at 4 h after embolic stroke improved substantially functional outcome and reduced by 80% the infract volume 7 days after stroke. Human 3K3A-APC was neuroprotective after embolic stroke in mice, but at significantly higher concentrations (i.e. 2 mg/kg i.v.). Species-dependent neuroprotection, i.e. murine > human 3K3A-APC, was confirmed in a mouse model of permanent middle cerebral artery occlusion. Human 3K3A-APC had by fivefold greater cytoprotective activity than murine 3K3A-APC in oxygen-glucose deprivation model in human brain endothelial cells, whereas murine 3K3A-APC was by 2.5-fold more potent than human 3K3A-APC in a mouse model of NMDA-induced neuronal apoptosis. Thus, 3K3A-APC exhibits species-dependent neuroprotection which should be taken into account when designing human trials for ischemic stroke with APC mutants.

SRF and myocardin regulate LRP-mediated amyloid-beta clearance in brain vascular cells.

Amyloid beta-peptide (Abeta) deposition in cerebral vessels contributes to cerebral amyloid angiopathy (CAA) in Alzheimer's disease (AD). Here, we report that in AD patients and two mouse models of AD, overexpression of serum response factor (SRF) and myocardin (MYOCD) in cerebral vascular smooth muscle cells (VSMCs) generates an Abeta non-clearing VSMC phenotype through transactivation of sterol regulatory element binding protein-2, which downregulates low density lipoprotein receptor-related protein-1, a key Abeta clearance receptor. Hypoxia stimulated SRF/MYOCD expression in human cerebral VSMCs and in animal models of AD. We suggest that SRF and MYOCD function as a transcriptional switch, controlling Abeta cerebrovascular clearance and progression of AD.

Differential neuroprotection and risk for bleeding from activated protein C with varying degrees of anticoagulant activity.

BACKGROUND AND PURPOSE: Activated protein C (APC), a protease with anticoagulant and cytoprotective activities, protects neurons and endothelium from ischemic injury. Drotrecogin-alfa activated, a hyperanticoagulant form of human recombinant APC, is currently being studied in patients with ischemic stroke. How changes in APC anticoagulant activity influence APC's neuroprotection and risk for bleeding is not clear. METHODS: We used neuronal and brain endothelial cell injury models and middle cerebral artery occlusion in mice to compare efficacy and safety of drotrecogin-alfa activated and human 3K3A-APC, an APC nonanticoagulant mutant. RESULTS: Drotrecogin-alfa activated and 3K3A-APC exhibited 148% and 10% of plasma-derived APC's anticoagulant activity and differ in the carbohydrate content. 3K3A-APC protected mouse neurons from N-methyl-d-aspartate-induced apoptosis and human brain endothelial cell from oxygen-glucose deprivation with 1.8- and 3.1-fold greater efficacy than drotrecogin-alfa activated. Given 5 minutes before transient middle cerebral artery occlusion, 3K3A-APC and drotrecogin-alfa activated (0.5 and 2 mg/kg intravenously) reduced comparably and dose-dependently the infarction lesion up to 85%. 3K3A-APC, but not drotrecogin-alfa activated, improved neurological score dose-dependently (P<0.05). 3K3A-APC did not cause bleeding. In contrast, drotrecogin-alfa activated dose-dependently increased hemoglobin content in postischemic brain. After permanent middle cerebral artery occlusion, 3K3A-APC multidose therapy (1 mg/kg intravenously at 12 hours and 1, 3, 5, and 7 days) improved functional recovery and reduced infarction by 60% with no risk for bleeding, whereas drotrecogin-alfa activated increased hemoglobin deposition in the postischemic brain and showed relatively modest neuroprotection. CONCLUSIONS: Nonanticoagulant 3K3A-APC exhibits greater neuroprotective efficacy with no risk for bleeding compared with drotrecogin-alfa activated, a hyperanticoagulant form of APC.

Serum response factor and myocardin mediate arterial hypercontractility and cerebral blood flow dysregulation in Alzheimer's phenotype.

Cerebral angiopathy contributes to cognitive decline and dementia in Alzheimer's disease (AD) through cerebral blood flow (CBF) reductions and dysregulation. We report vascular smooth muscle cells (VSMC) in small pial and intracerebral arteries, which are critical for CBF regulation, express in AD high levels of serum response factor (SRF) and myocardin (MYOCD), two interacting transcription factors that orchestrate a VSMC-differentiated phenotype. Consistent with this finding, AD VSMC overexpressed several SRF-MYOCD-regulated contractile proteins and exhibited a hypercontractile phenotype. MYOCD overexpression in control human cerebral VSMC induced an AD-like hypercontractile phenotype and diminished both endothelial-dependent and -independent relaxation in the mouse aorta ex vivo. In contrast, silencing SRF normalized contractile protein content and reversed a hypercontractile phenotype in AD VSMC. MYOCD in vivo gene transfer to mouse pial arteries increased contractile protein content and diminished CBF responses produced by brain activation in wild-type mice and in two AD models, the Dutch/Iowa/Swedish triple mutant human amyloid beta-peptide (Abeta)-precursor protein (APP)- expressing mice and APPsw(+/-) mice. Silencing Srf had the opposite effect. Expression of SRF did not change in VSMC subjected to Alzheimer's neurotoxin, Abeta. Thus, SRF-MYOCD overexpression in small cerebral arteries appears to initiate independently of Abeta a pathogenic pathway mediating arterial hypercontractility and CBF dysregulation, which are associated with Alzheimer's dementia.

Role of the MEOX2 homeobox gene in neurovascular dysfunction in Alzheimer disease.

Neurovascular dysfunction substantially contributes to Alzheimer disease. Here, we show that transcriptional profiling of human brain endothelial cells (BECs) defines a subset of genes whose expression is age-independent but is considerably altered in Alzheimer disease, including the homeobox gene MEOX2 (also known as GAX), a regulator of vascular differentiation, whose expression is low in Alzheimer disease. By using viral-mediated MEOX2 gene silencing and transfer, we show that restoring expression of the protein it encodes, GAX, in BECs from individuals with Alzheimer disease stimulates angiogenesis, transcriptionally suppresses AFX1 forkhead transcription factor-mediated apoptosis and increases the levels of a major amyloid-beta peptide (Abeta) clearance receptor, the low-density lipoprotein receptor-related protein 1 (LRP), at the blood-brain barrier. In mice, deletion of Meox2 (also known as Gax) results in reductions in brain capillary density and resting cerebral blood flow, loss of the angiogenic response to hypoxia in the brain and an impaired Abeta efflux from brain caused by reduced LRP levels. The link of MEOX2 to neurovascular dysfunction in Alzheimer disease provides new mechanistic and therapeutic insights into this illness.

Neurovascular pathways and Alzheimer amyloid beta-peptide.

According to the prevailing amyloid cascade hypothesis, the onset and progression of a chronic neurodegenerative condition in Alzheimer disease (AD) is initiated by the amyloid beta-peptide (Abeta) accumulation in brain and consequent neuronal toxicity. Recent emphasis on co-morbidity of AD and cerebrovascular disease and the recognition that cerebrovascular dysregulation is an important feature of AD, has shed new light on neurovascular dysfunction as a possible contributor to cognitive decline and Alzheimer neurodegeneration. In the same time, this association has raised a question as to whether there is a causal relationship between cerebrovascular dysregulation and Abeta-initiated pathology, and whether influencing targets in the neurovasculature may prevent different forms of Abeta brain accumulation and/or lower pre-existing accumulates in a later stage of the disease. Pathogenic cascades which operate to dissociate normal transport exchanges between central and peripheral pools of Abeta, and decreased vascular competence leading to brain hypoperfusion and impaired Abeta clearance are discussed. We suggest that there is a link between neurovascular dysfunction and elevated brain Abeta which provides a new scenario for therapeutic interventions to control Alzheimer mental deterioration.