1
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Waigi EW, Pernomian L, Crockett AM, Costa TJ, Townsend P, Webb RC, McQuail JA, McCarthy CG, Hollis F, Wenceslau CF. Vascular dysfunction occurs prior to the onset of amyloid pathology and Aβ plaque deposits colocalize with endothelial cells in the hippocampus of female APPswe/PSEN1dE9 mice. GeroScience 2024:10.1007/s11357-024-01213-0. [PMID: 38862757 DOI: 10.1007/s11357-024-01213-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 05/18/2024] [Indexed: 06/13/2024] Open
Abstract
Increasing evidence shows that cardiovascular diseases (CVDs) are associated with an increased risk of cognitive impairment and Alzheimer's diseases (AD). It is unknown whether systemic vascular dysfunction occurs prior to the development of AD, if this occurs in a sex-dependent manner, and whether endothelial cells play a role in the deposition of amyloid beta (Aβ) peptides. We hypothesized that vascular dysfunction occurs prior to the onset of amyloid pathology, thus escalating its progression. Furthermore, endothelial cells from female mice will present with an exacerbated formation of Aβ peptides due to an exacerbated pressure pulsatility. To test this hypothesis, we used a double transgenic mouse model of early-onset AD (APPswe/PSEN1dE9). We evaluated hippocampus-dependent recognition memory and the cardiovascular function by echocardiography and direct measurements of blood pressure through carotid artery catheterization. Vascular function was evaluated in resistance arteries, morphometric parameters in the aortas, and immunofluorescence in the hippocampus and aortas. We observed that endothelial dysfunction occurred prior to the onset of amyloid pathology irrespective of sex. However, during the onset of amyloid pathology, only female APP/PS1 mice had vascular stiffness in the aorta. There was elevated Aβ deposition which colocalized with endothelial cells in the hippocampus from female APP/PS1 mice. Overall, these data showed that vascular abnormalities may be an early marker, and potential mediator of AD, but exacerbated aortic stiffness and pressure pulsatility after the onset of amyloid pathology may be associated with a greater burden of Aβ formation in hippocampal endothelial cells from female but not male APP/PS1 mice.
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Affiliation(s)
- Emily W Waigi
- Cardiovascular Translational Research Center, Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Laena Pernomian
- Cardiovascular Translational Research Center, Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Alexia M Crockett
- Cardiovascular Translational Research Center, Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC, USA
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Tiago J Costa
- Cardiovascular Translational Research Center, Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Paul Townsend
- Cardiovascular Translational Research Center, Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC, USA
| | - R Clinton Webb
- Cardiovascular Translational Research Center, Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC, USA
- Department of Biomedical Engineering, College of Engineering and Computing, University of South Carolina, Columbia, SC, USA
| | - Joseph A McQuail
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Cameron G McCarthy
- Cardiovascular Translational Research Center, Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC, USA
- Department of Biomedical Engineering, College of Engineering and Computing, University of South Carolina, Columbia, SC, USA
| | - Fiona Hollis
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - Camilla F Wenceslau
- Cardiovascular Translational Research Center, Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC, USA.
- Department of Biomedical Engineering, College of Engineering and Computing, University of South Carolina, Columbia, SC, USA.
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2
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Sasahara T, Satomura K, Tada M, Kakita A, Hoshi M. Alzheimer's Aβ assembly binds sodium pump and blocks endothelial NOS activity via ROS-PKC pathway in brain vascular endothelial cells. iScience 2021; 24:102936. [PMID: 34458695 PMCID: PMC8379508 DOI: 10.1016/j.isci.2021.102936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/24/2021] [Accepted: 07/29/2021] [Indexed: 01/12/2023] Open
Abstract
Amyloid β-protein (Aβ) may contribute to worsening of Alzheimer's disease (AD) through vascular dysfunction, but the molecular mechanism involved is unknown. Using ex vivo blood vessels and primary endothelial cells from human brain microvessels, we show that patient-derived Aβ assemblies, termed amylospheroids (ASPD), exist on the microvascular surface in patients' brains and inhibit vasorelaxation through binding to the α3 subunit of sodium, potassium-ATPase (NAKα3) in caveolae on endothelial cells. Interestingly, NAKα3 is also the toxic target of ASPD in neurons. ASPD-NAKα3 interaction elicits neurodegeneration through calcium overload in neurons, while the same interaction suppresses vasorelaxation by increasing the inactive form of endothelial nitric oxide synthase (eNOS) in endothelial cells via mitochondrial ROS and protein kinase C, independently of the physiological relaxation system. Thus, ASPD may contribute to both neuronal and vascular pathologies through binding to NAKα3. Therefore, blocking the ASPD-NAKα3 interaction may be a useful target for AD therapy.
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Affiliation(s)
- Tomoya Sasahara
- Department for Brain and Neurodegenerative Disease Research, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, CLIK 6F 6-3-7 Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan
- TAO Health Life Pharma Co., Ltd., Med-Pharma Collaboration Bldg, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Kaori Satomura
- Department for Brain and Neurodegenerative Disease Research, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, CLIK 6F 6-3-7 Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan
- TAO Health Life Pharma Co., Ltd., Med-Pharma Collaboration Bldg, Kyoto University, 46-29 Yoshida Shimoadachi-cho, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Mari Tada
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Minako Hoshi
- Department for Brain and Neurodegenerative Disease Research, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, CLIK 6F 6-3-7 Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
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3
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Li S, Wang C, Wang Z, Tan J. Involvement of cerebrovascular abnormalities in the pathogenesis and progression of Alzheimer's disease: an adrenergic approach. Aging (Albany NY) 2021; 13:21791-21806. [PMID: 34479211 PMCID: PMC8457611 DOI: 10.18632/aging.203482] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 08/17/2021] [Indexed: 01/09/2023]
Abstract
Alzheimer's disease (AD), as the most common neurodegenerative disease in elder population, is pathologically characterized by β-amyloid (Aβ) plaques, neurofibrillary tangles composed of highly-phosphorylated tau protein and consequently progressive neurodegeneration. However, both Aβ and tau fails to cover the whole pathological process of AD, and most of the Aβ- or tau-based therapeutic strategies are all failed. Increasing lines of evidence from both clinical and preclinical studies have indicated that age-related cerebrovascular dysfunctions, including the changes in cerebrovascular microstructure, blood-brain barrier integrity, cerebrovascular reactivity and cerebral blood flow, accompany or even precede the development of AD-like pathologies. These findings may raise the possibility that cerebrovascular changes are likely pathogenic contributors to the onset and progression of AD. In this review, we provide an appraisal of the cerebrovascular alterations in AD and the relationship to cognitive impairment and AD pathologies. Moreover, the adrenergic mechanisms leading to cerebrovascular and AD pathologies were further discussed. The contributions of early cerebrovascular factors, especially through adrenergic mechanisms, should be considered and treasured in the diagnostic, preventative, and therapeutic approaches to address AD.
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Affiliation(s)
- Song Li
- Liaoning Provincial Center for Clinical Research on Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian 116021, China.,Liaoning Provincial Key Laboratory for Research on the Pathogenic Mechanisms of Neurological Diseases, The First Affiliated Hospital, Dalian Medical University, Dalian 116021, China
| | - Che Wang
- Department of Pharmaceutical Chemistry, School of Chemistry and Chemical Engineering, Liaoning Normal University, Dalian 116029, China
| | - Zhen Wang
- Department of Neurology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou 325000, China
| | - Jun Tan
- Key Laboratory of Endemic and Ethnic Diseases, Guizhou Medical University, Guiyang 550004, China
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4
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Lai CC, Lo H, Lin HG, Lin HH. Potentiation of NMDA-Mediated Responses by Amyloid-β Peptide 1-40 in Rat Sympathetic Preganglionic Neurons. J Alzheimers Dis 2020; 67:1291-1303. [PMID: 30714959 DOI: 10.3233/jad-180886] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The abnormal accumulation of amyloid-β peptides (Aβ) is one of the main characteristics of Alzheimer's disease (AD). Cerebro- and cardiovascular diseases may be the risk factors for developing AD. The effect of Aβ on central sympathetic control of cardiovascular function remains unclear. The present study examines the acute effects of Aβ oligomers on the function of NMDA receptors, a subtype of ionotropic glutamate receptors, in rat sympathetic preganglionic neurons (SPNs). In the in vitro electrophysiological study, Aβ1-40 but not Aβ1-42 applied by superfusion for 5 min significantly potentiated NMDA-induced depolarizations in SPNs of neonatal rat spinal cord slice preparation. Application of Aβ1-40 had little effects on AMPA-induced depolarizations or GABA-induced hyperpolarizations. Treatment with a selective protein kinase C (PKC) inhibitor applied together with Aβ1-40 blocked the augmentation by Aβ1-40 of NMDA-induced depolarizations. Western blot analysis showed an increase in the levels of phosphoserine 896, selectively regulated by PKC, without significant changes in phosphoserine 897 on GluN1 subunits in lateral horn areas of spinal cord slices following treatment with Aβ1-40. In the in vivo study, intrathecal injection of Aβ1-40 (0.2 nmol) potentiated the pressor effects induced by NMDA (2 nmol) injected intrathecally in urethane-anesthetized rats. These results suggest that different fragments of Aβ may have differential effects on the NMDA receptor function and the selective augmentation of NMDA receptor function by Aβ1-40 may involve PKC-dependent mechanisms in sympathetic preganglionic neurons.
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Affiliation(s)
- Chih-Chia Lai
- Department of Pharmacology, School of Medicine, Tzu Chi University, Hualien, Taiwan.,Master and PhD Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Hsuan Lo
- Master and PhD Programs in Pharmacology and Toxicology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Hong-Guo Lin
- Master Program in Medical Physiology, School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Hsun-Hsun Lin
- Master Program in Medical Physiology, School of Medicine, Tzu Chi University, Hualien, Taiwan.,Department of Physiology, School of Medicine, Tzu Chi University, Hualien, Taiwan
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5
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Alfini AJ, Weiss LR, Nielson KA, Verber MD, Smith JC. Resting Cerebral Blood Flow After Exercise Training in Mild Cognitive Impairment. J Alzheimers Dis 2020; 67:671-684. [PMID: 30636734 DOI: 10.3233/jad-180728] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Exercise training has been associated with greater cerebral blood flow (CBF) in cognitively normal older adults (CN). Alterations in CBF, including compensatory perfusion in the prefrontal cortex, may facilitate changes to the brain's neural infrastructure. OBJECTIVE To examine the effects of a 12-week aerobic exercise intervention on resting CBF and cognition in CN and those with mild cognitive impairment (MCI). We hypothesized individuals with MCI (versus CN) would exhibit greater whole brain CBF at baseline and that exercise would mitigate these differences. We also expected CBF changes to parallel cognitive improvements. METHODS Before and after a 12-week exercise intervention, 18 CN and 17 MCI participants (aged 61-88) underwent aerobic fitness testing, neuropsychological assessment, and an MRI scan. Perfusion-weighted images were collected using a GE 3T MR system. Repeated measures analyses of covariance were used to test within- and between-group differences over time, followed by post-hoc analyses to examine links between CBF changes and cognitive improvement. RESULTS At baseline, individuals with MCI (versus CN) exhibited significantly elevated perfusion in the left insula. Twelve weeks of aerobic exercise reversed this discrepancy. Additionally, exercise improved working memory (measured by the Rey Auditory Verbal Learning Test) and verbal fluency (measured by the Controlled Oral Word Association Test) and differentially altered CBF depending on cognitive status. Among those with MCI, decreased CBF in the left insula and anterior cingulate cortex was associated with improved verbal fluency. CONCLUSIONS Exercise training alters CBF and improves cognitive performance in older adults with and without cognitive impairment. Future studies must evaluate the mediating effects of CBF on the association between exercise training and cognition.
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Affiliation(s)
- Alfonso J Alfini
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Lauren R Weiss
- Department of Kinesiology, University of Maryland, College Park, MD, USA.,Program in Neuroscience and Cognitive Science, University of Maryland, College Park, MD, USA
| | - Kristy A Nielson
- Department of Psychology, Marquette University, Milwaukee, WI, USA.,Department of Neuropsychology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Matthew D Verber
- Department of Chemistry, University of North Carolina, Chapel Hill, NC, USA
| | - J Carson Smith
- Department of Kinesiology, University of Maryland, College Park, MD, USA.,Program in Neuroscience and Cognitive Science, University of Maryland, College Park, MD, USA
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6
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Liao X, Cai F, Sun Z, Zhang Y, Wang J, Jiao B, Guo J, Li J, Liu X, Guo L, Zhou Y, Wang J, Yan X, Jiang H, Xia K, Li J, Tang B, Shen L, Song W. Identification of Alzheimer's disease-associated rare coding variants in the ECE2 gene. JCI Insight 2020; 5:135119. [PMID: 32102983 DOI: 10.1172/jci.insight.135119] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 01/29/2020] [Indexed: 11/17/2022] Open
Abstract
Accumulation of amyloid β protein (Aβ) due to increased generation and/or impaired degradation plays an important role in Alzheimer's disease (AD) pathogenesis. In this report, we describe the identification of rare coding mutations in the endothelin-converting enzyme 2 (ECE2) gene in 1 late-onset AD family, and additional case-control cohort analysis indicates ECE2 variants associated with the risk of developing AD. The 2 mutations (R186C and F751S) located in the peptidase domain in the ECE2 protein were found to severely impair the enzymatic activity of ECE2 in Aβ degradation. We further evaluated the effect of the R186C mutation in mutant APP-knockin mice. Overexpression of wild-type ECE2 in the hippocampus reduced amyloid load and plaque formation, and improved learning and memory deficits in the AD model mice. However, the effect was abolished by the R186C mutation in ECE2. Taken together, the results demonstrated that ECE2 peptidase mutations contribute to AD pathogenesis by impairing Aβ degradation, and overexpression of ECE2 alleviates AD phenotypes. This study indicates that ECE2 is a risk gene for AD development and pharmacological activation of ECE2 could be a promising strategy for AD treatment.
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Affiliation(s)
- Xinxin Liao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, Canada.,National Clinical Research Center for Geriatric Disorders
| | - Fang Cai
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, Canada
| | - Zhanfang Sun
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Yun Zhang
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, Canada
| | - Juelu Wang
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, Canada
| | - Bin Jiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Jifeng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China
| | - Jinchen Li
- National Clinical Research Center for Geriatric Disorders
| | - Xixi Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Lina Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Yafang Zhou
- National Clinical Research Center for Geriatric Disorders
| | - Junling Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Xinxiang Yan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China
| | - Kun Xia
- School of Life Sciences, and
| | | | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan, China
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, The University of British Columbia, Vancouver, Canada
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7
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Govindpani K, McNamara LG, Smith NR, Vinnakota C, Waldvogel HJ, Faull RL, Kwakowsky A. Vascular Dysfunction in Alzheimer's Disease: A Prelude to the Pathological Process or a Consequence of It? J Clin Med 2019; 8:E651. [PMID: 31083442 PMCID: PMC6571853 DOI: 10.3390/jcm8050651] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 04/29/2019] [Accepted: 05/06/2019] [Indexed: 12/19/2022] Open
Abstract
Alzheimer's disease (AD) is the most prevalent form of dementia. Despite decades of research following several theoretical and clinical lines, all existing treatments for the disorder are purely symptomatic. AD research has traditionally been focused on neuronal and glial dysfunction. Although there is a wealth of evidence pointing to a significant vascular component in the disease, this angle has been relatively poorly explored. In this review, we consider the various aspects of vascular dysfunction in AD, which has a significant impact on brain metabolism and homeostasis and the clearance of β-amyloid and other toxic metabolites. This may potentially precede the onset of the hallmark pathophysiological and cognitive symptoms of the disease. Pathological changes in vessel haemodynamics, angiogenesis, vascular cell function, vascular coverage, blood-brain barrier permeability and immune cell migration may be related to amyloid toxicity, oxidative stress and apolipoprotein E (APOE) genotype. These vascular deficits may in turn contribute to parenchymal amyloid deposition, neurotoxicity, glial activation and metabolic dysfunction in multiple cell types. A vicious feedback cycle ensues, with progressively worsening neuronal and vascular pathology through the course of the disease. Thus, a better appreciation for the importance of vascular dysfunction in AD may open new avenues for research and therapy.
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Affiliation(s)
- Karan Govindpani
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Laura G McNamara
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Nicholas R Smith
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Chitra Vinnakota
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Henry J Waldvogel
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Richard Lm Faull
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
| | - Andrea Kwakowsky
- Centre for Brain Research, Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
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8
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Tayler HM, Palmer JC, Thomas TL, Kehoe PG, Paton JF, Love S. Cerebral Aβ 40 and systemic hypertension. J Cereb Blood Flow Metab 2018; 38:1993-2005. [PMID: 28782443 PMCID: PMC6259324 DOI: 10.1177/0271678x17724930] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mid-life hypertension and cerebral hypoperfusion may be preclinical abnormalities in people who later develop Alzheimer's disease. Although accumulation of amyloid-beta (Aβ) is characteristic of Alzheimer's disease and is associated with upregulation of the vasoconstrictor peptide endothelin-1 within the brain, it is unclear how this affects systemic arterial pressure. We have investigated whether infusion of Aβ40 into ventricular cerebrospinal fluid modulates blood pressure in the Dahl salt-sensitive rat. The Dahl salt-sensitive rat develops hypertension if given a high-salt diet. Intracerebroventricular infusion of Aβ induced a progressive rise in blood pressure in rats with pre-existing hypertension produced by a high-salt diet ( p < 0.0001), but no change in blood pressure in normotensive rats. The elevation in arterial pressure in high-salt rats was associated with an increase in low frequency spectral density in systolic blood pressure, suggesting autonomic imbalance, and reduced cardiac baroreflex gain. Our results demonstrate the potential for intracerebral Aβ to exacerbate hypertension, through modulation of autonomic activity. Present findings raise the possibility that mid-life hypertension in people who subsequently develop Alzheimer's disease may in some cases be a physiological response to reduced cerebral perfusion complicating the accumulation of Aβ within the brain.
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Affiliation(s)
- Hannah M Tayler
- 1 School of Clinical Sciences, University of Bristol, Bristol, UK
| | | | - Taya L Thomas
- 1 School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Patrick G Kehoe
- 1 School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Julian Fr Paton
- 2 School of Physiology, Pharmacology & Neuroscience, Biomedical Sciences, University of Bristol, Bristol, UK
| | - Seth Love
- 1 School of Clinical Sciences, University of Bristol, Bristol, UK
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9
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Ngwa JS, Fungwe TV, Ntekim O, Allard JS, Johnson SM, Castor C, Graham L, Nadarajah S, Gillum RF, Obisesan TO. Associations of Pulse and Blood Pressure with Hippocampal Volume by APOE and Cognitive Phenotype: The Alzheimer's Disease Neuroimaging Initiative (ADNI). Dement Geriatr Cogn Disord 2018; 45:66-78. [PMID: 29694964 PMCID: PMC6143389 DOI: 10.1159/000486955] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 01/17/2018] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND It is increasingly evident that high blood pressure can promote reduction in global and regional brain volumes. While these effects may preferentially affect the hippocampus, reports are inconsistent. METHODS Using data from the Alzheimer's Disease Neuroimaging Initiative (ADNI), we examined the relationships of hippocampal volume to pulse pressure (PPR) and systolic (SBP) and diastolic (DBP) blood pressure according to apolipoprotein (APOE) ɛ4 positivity and cognitive status. The ADNI data included 1,308 participants: Alzheimer disease (AD = 237), late mild cognitive impairment (LMCI = 454), early mild cognitive impairment (EMCI = 254), and cognitively normal (CN = 365), with up to 24 months of follow-up. RESULTS Higher quartiles of PPR were significantly associated with lower hippocampal volumes (Q1 vs. Q4, p = 0.034) in the CN and AD groups, but with increasing hippocampal volume (Q1, p = 0.008; Q2, p = 0.020; Q3, p = 0.017; Q4 = reference) in the MCI groups. In adjusted stratified analyses among non-APOE ɛ4 carriers, the effects in the CN (Q1 vs. Q4, p = 0.006) and EMCI groups (Q1, p = 0.002; Q2, p = 0.013; Q3, p = 0.002; Q4 = reference) remained statistically significant. Also, higher DBP was significantly associated with higher hippocampal volume (p = 0.002) while higher SBP was significantly associated with decreasing hippocampal volume in the EMCI group (p = 0.015). CONCLUSION Changes in PPR, SBP, and DBP differentially influenced hippocampal volumes depending on the cognitive and APOE genotypic categories.
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Affiliation(s)
- Julius S. Ngwa
- Division of Cardiovascular Medicine, Department of Medicine, Howard University College of Medicine, Washington, DC, USA
| | - Thomas V. Fungwe
- Department of Nutritional Sciences, School of Nursing and Allied Health Sciences, and Department of Medicine, Howard University College of Medicine, Washington, DC, USA
| | - Oyonumo Ntekim
- Department of Nutritional Sciences, School of Nursing and Allied Health Sciences, and Department of Medicine, Howard University College of Medicine, Washington, DC, USA
| | - Joanne S. Allard
- Department of Physiology and Biophysics, Howard University College of Medicine, Washington, DC, USA
| | - Sheree M. Johnson
- Department of Physiology and Biophysics, Howard University College of Medicine, Washington, DC, USA
| | - Chimene Castor
- Department of Nutritional Sciences, School of Nursing and Allied Health Sciences, and Department of Medicine, Howard University College of Medicine, Washington, DC, USA
| | - Lennox Graham
- Department of Health Education, School of Nursing and Allied Health Sciences, and Department of Medicine, Howard University College of Medicine, Washington, DC, USA
| | - Sheeba Nadarajah
- Division of Nursing, School of Nursing and Allied Health Sciences, and Department of Medicine, Howard University College of Medicine, Washington, DC, USA
| | - Richard F. Gillum
- Division of Geriatrics, Department of Medicine and Clinical/Translational Science Program, Howard University College of Medicine/ Hospital, Washington, DC, USA
| | - Thomas O. Obisesan
- Division of Geriatrics, Department of Medicine and Clinical/Translational Science Program, Howard University College of Medicine/ Hospital, Washington, DC, USA
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10
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d'Uscio LV, He T, Katusic ZS. Expression and Processing of Amyloid Precursor Protein in Vascular Endothelium. Physiology (Bethesda) 2017; 32:20-32. [PMID: 27927802 DOI: 10.1152/physiol.00021.2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amyloid precursor protein (APP) is evolutionary conserved protein expressed in endothelial cells of cerebral and peripheral arteries. In this review, we discuss mechanisms responsible for expression and proteolytic cleavage of APP in endothelial cells. We focus on physiological and pathological implications of APP expression in vascular endothelium.
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Affiliation(s)
- Livius V d'Uscio
- Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Tongrong He
- Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Zvonimir S Katusic
- Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota
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11
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Navarro-Dorado J, Villalba N, Prieto D, Brera B, Martín-Moreno AM, Tejerina T, de Ceballos ML. Vascular Dysfunction in a Transgenic Model of Alzheimer's Disease: Effects of CB1R and CB2R Cannabinoid Agonists. Front Neurosci 2016; 10:422. [PMID: 27695396 PMCID: PMC5025475 DOI: 10.3389/fnins.2016.00422] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 08/29/2016] [Indexed: 01/21/2023] Open
Abstract
There is evidence of altered vascular function, including cerebrovascular, in Alzheimer's disease (AD) and transgenic models of the disease. Indeed vasoconstrictor responses are increased, while vasodilation is reduced in both conditions. β-Amyloid (Aβ) appears to be responsible, at least in part, of alterations in vascular function. Cannabinoids, neuroprotective and anti-inflammatory agents, induce vasodilation both in vivo and in vitro. We have demonstrated a beneficial effect of cannabinoids in models of AD by preventing glial activation. In this work we have studied the effects of these compounds on vessel density in amyloid precursor protein (APP) transgenic mice, line 2576, and on altered vascular responses in aortae isolated ring. First we showed increased collagen IV positive vessels in AD brain compared to control subjects, with a similar increase in TgAPP mice, which was normalized by prolonged oral treatment with the CB1/CB2 mixed agonist WIN 55,212-2 (WIN) and the CB2 selective agonist JWH-133 (JWH). In Tg APP mice the vasoconstriction induced by phenylephrine and the thromboxane agonist U46619 was significantly increased, and no change in the vasodilation to acetylcholine (ACh) was observed. Tg APP displayed decreased vasodilation to both cannabinoid agonists, which were able to prevent decreased ACh relaxation in the presence of Aβ. In summary, we have confirmed and extended the existence of altered vascular responses in Tg APP mice. Moreover, our results suggest that treatment with cannabinoids may ameliorate the vascular responses in AD-type pathology.
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Affiliation(s)
- Jorge Navarro-Dorado
- Department of Pharmacology, School of Medicine, Complutense University of Madrid Madrid, Spain
| | - Nuria Villalba
- Department of Physiology, Faculty of Pharmacy, Complutense University of Madrid Madrid, Spain
| | - Dolores Prieto
- Department of Physiology, Faculty of Pharmacy, Complutense University of Madrid Madrid, Spain
| | - Begoña Brera
- Neurodegeneration Group, Cellular, Molecular and Developmental Neurobiology and CIBERNED, Cajal Institute, CSIC Madrid, Spain
| | - Ana M Martín-Moreno
- Neurodegeneration Group, Cellular, Molecular and Developmental Neurobiology and CIBERNED, Cajal Institute, CSIC Madrid, Spain
| | - Teresa Tejerina
- Department of Pharmacology, School of Medicine, Complutense University of Madrid Madrid, Spain
| | - María L de Ceballos
- Neurodegeneration Group, Cellular, Molecular and Developmental Neurobiology and CIBERNED, Cajal Institute, CSIC Madrid, Spain
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12
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Love S, Miners J. Cerebral Hypoperfusion and the Energy Deficit in Alzheimer's Disease. Brain Pathol 2016; 26:607-17. [PMID: 27327656 PMCID: PMC8028913 DOI: 10.1111/bpa.12401] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 06/21/2016] [Accepted: 05/25/2016] [Indexed: 12/19/2022] Open
Abstract
There is a perfusion deficit in Alzheimer's disease (AD), commencing in the precuneus and spreading to other parts of the cerebral cortex. The deficit anticipates the development of dementia, contributes to brain damage, and is caused by both functional and structural abnormalities of the cerebral vasculature. Most of the abnormalities are probably secondary to the accumulation of Aβ but the consequent hypoperfusion may, in turn, increase Aβ production. In the early stages of disease, abnormalities that cause vasoconstriction predominate. These include cholinergic vascular denervation, inhibition of endothelial nitric oxide synthase, increased production of endothelin-1 production and possibly also of angiotensin II. Patients with AD also have an increased prevalence of structural disease of cerebral microvessels, particularly CAA and capillary damage, and particularly in the later stages of disease these are likely to make an important contribution to the cerebral hypoperfusion. The metabolic abnormalities that cause early vascular dysfunction offer several targets for therapeutic intervention. However, for intervention to be effective it probably needs to be early. Prolonged cerebral hypoperfusion may induce compensatory circulatory changes that are themselves damaging, including hypertension and small vessel disease. This has implications for the use of antihypertensive drugs once there is accumulation of Aβ within the brain.
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Affiliation(s)
- Seth Love
- Dementia Research Group, Institute of Clinical Neurosciences, School of Clinical SciencesUniversity of BristolBristolUnited Kingom
| | - J.Scott Miners
- Dementia Research Group, Institute of Clinical Neurosciences, School of Clinical SciencesUniversity of BristolBristolUnited Kingom
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13
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Yousefirad N, Kaygisiz Z, Aydin Y. The Effects of Beta Amyloid Peptide 1-42 on Isolated Rat Hearts and Ileum Smooth Muscle. Pharmacology 2016; 98:261-266. [DOI: 10.1159/000448590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 07/21/2016] [Indexed: 11/19/2022]
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14
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Daulatzai MA. Dysfunctional Sensory Modalities, Locus Coeruleus, and Basal Forebrain: Early Determinants that Promote Neuropathogenesis of Cognitive and Memory Decline and Alzheimer’s Disease. Neurotox Res 2016; 30:295-337. [DOI: 10.1007/s12640-016-9643-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/08/2016] [Accepted: 06/10/2016] [Indexed: 12/22/2022]
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15
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Reynolds MR, Singh I, Azad TD, Holmes BB, Verghese PB, Dietrich HH, Diamond M, Bu G, Han BH, Zipfel GJ. Heparan sulfate proteoglycans mediate Aβ-induced oxidative stress and hypercontractility in cultured vascular smooth muscle cells. Mol Neurodegener 2016; 11:9. [PMID: 26801396 PMCID: PMC4722750 DOI: 10.1186/s13024-016-0073-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 01/12/2016] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Substantial evidence suggests that amyloid-β (Aβ) species induce oxidative stress and cerebrovascular (CV) dysfunction in Alzheimer's disease (AD), potentially contributing to the progressive dementia of this disease. The upstream molecular pathways governing this process, however, are poorly understood. In this report, we examine the role of heparan sulfate proteoglycans (HSPG) in Aβ-induced vascular smooth muscle cell (VSMC) dysfunction in vitro. RESULTS Our results demonstrate that pharmacological depletion of HSPG (by enzymatic degradation with active, but not heat-inactivated, heparinase) in primary human cerebral and transformed rat VSMC mitigates Aβ(1-40⁻) and Aβ(1-42⁻)induced oxidative stress. This inhibitory effect is specific for HSPG depletion and does not occur with pharmacological depletion of other glycosaminoglycan (GAG) family members. We also found that Aβ(1-40) (but not Aβ(1-42)) causes a hypercontractile phenotype in transformed rat cerebral VSMC that likely results from a HSPG-mediated augmentation in intracellular Ca(2+) activity, as both Aβ(1-40⁻)induced VSMC hypercontractility and increased Ca(2+) influx are inhibited by pharmacological HSPG depletion. Moreover, chelation of extracellular Ca(2+) with ethylene glycol tetraacetic acid (EGTA) does not prevent the production of Aβ(1-40⁻) or Aβ(1-42⁻)mediated reactive oxygen species (ROS), suggesting that Aβ-induced ROS and VSMC hypercontractility occur through different molecular pathways. CONCLUSIONS Taken together, our data indicate that HSPG are critical mediators of Aβ-induced oxidative stress and Aβ(1-40⁻)induced VSMC dysfunction.
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Affiliation(s)
- Matthew R Reynolds
- Department of Neurological Surgery, Washington University School of Medicine, Hope Center Program on Protein Aggregation and Neurodegeneration, Charles F. and Joanne Knight Alzheimer's Disease Research Center, Campus Box 8057, 660 South Euclid Avenue, St. Louis, Missouri, 63110, USA
| | - Itender Singh
- Department of Neurological Surgery, Washington University School of Medicine, Hope Center Program on Protein Aggregation and Neurodegeneration, Charles F. and Joanne Knight Alzheimer's Disease Research Center, Campus Box 8057, 660 South Euclid Avenue, St. Louis, Missouri, 63110, USA
| | - Tej D Azad
- Department of Neurological Surgery, Washington University School of Medicine, Hope Center Program on Protein Aggregation and Neurodegeneration, Charles F. and Joanne Knight Alzheimer's Disease Research Center, Campus Box 8057, 660 South Euclid Avenue, St. Louis, Missouri, 63110, USA
| | - Brandon B Holmes
- Department of Neurology, Washington University School of Medicine, Hope Center Program on Protein Aggregation and Neurodegeneration, Charles F. and Joanne Knight Alzheimer's Disease Research Center, St. Louis, Missouri, USA
| | - Phillip B Verghese
- Department of Neurology, Washington University School of Medicine, Hope Center Program on Protein Aggregation and Neurodegeneration, Charles F. and Joanne Knight Alzheimer's Disease Research Center, St. Louis, Missouri, USA
| | - Hans H Dietrich
- Department of Neurological Surgery, Washington University School of Medicine, Hope Center Program on Protein Aggregation and Neurodegeneration, Charles F. and Joanne Knight Alzheimer's Disease Research Center, Campus Box 8057, 660 South Euclid Avenue, St. Louis, Missouri, 63110, USA
| | - Marc Diamond
- Center for Alzheimer's and Neurodegenerative Diseases, UT Southwestern, Dallas, Texas, USA
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, Florida, USA
| | - Byung Hee Han
- Department of Pharmacology, AT Still University Health Sciences, Kirksville, Missouri, USA
| | - Gregory J Zipfel
- Department of Neurological Surgery, Washington University School of Medicine, Hope Center Program on Protein Aggregation and Neurodegeneration, Charles F. and Joanne Knight Alzheimer's Disease Research Center, Campus Box 8057, 660 South Euclid Avenue, St. Louis, Missouri, 63110, USA.
- Department of Neurology, Washington University School of Medicine, Hope Center Program on Protein Aggregation and Neurodegeneration, Charles F. and Joanne Knight Alzheimer's Disease Research Center, St. Louis, Missouri, USA.
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16
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Yang SH, Li W, Sumien N, Forster M, Simpkins JW, Liu R. Alternative mitochondrial electron transfer for the treatment of neurodegenerative diseases and cancers: Methylene blue connects the dots. Prog Neurobiol 2015; 157:273-291. [PMID: 26603930 DOI: 10.1016/j.pneurobio.2015.10.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 09/10/2015] [Accepted: 10/20/2015] [Indexed: 12/21/2022]
Abstract
Brain has exceptional high requirement for energy metabolism with glucose as the exclusive energy source. Decrease of brain energy metabolism and glucose uptake has been found in patients of Alzheimer's, Parkinson's and other neurodegenerative diseases, providing a clear link between neurodegenerative disorders and energy metabolism. On the other hand, cancers, including glioblastoma, have increased glucose uptake and rely on aerobic glycolysis for energy metabolism. The switch of high efficient oxidative phosphorylation to low efficient aerobic glycolysis pathway (Warburg effect) provides macromolecule for biosynthesis and proliferation. Current research indicates that methylene blue, a century old drug, can receive electron from NADH in the presence of complex I and donates it to cytochrome c, providing an alternative electron transfer pathway. Methylene blue increases oxygen consumption, decrease glycolysis, and increases glucose uptake in vitro. Methylene blue enhances glucose uptake and regional cerebral blood flow in rats upon acute treatment. In addition, methylene blue provides protective effect in neuron and astrocyte against various insults in vitro and in rodent models of Alzheimer's, Parkinson's, and Huntington's disease. In glioblastoma cells, methylene blue reverses Warburg effect by enhancing mitochondrial oxidative phosphorylation, arrests glioma cell cycle at s-phase, and inhibits glioma cell proliferation. Accordingly, methylene blue activates AMP-activated protein kinase, inhibits downstream acetyl-coA carboxylase and cyclin-dependent kinases. In summary, there is accumulating evidence providing a proof of concept that enhancement of mitochondrial oxidative phosphorylation via alternative mitochondrial electron transfer may offer protective action against neurodegenerative diseases and inhibit cancers proliferation.
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Affiliation(s)
- Shao-Hua Yang
- Center for Neuroscience Discovery, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
| | - Wenjun Li
- Center for Neuroscience Discovery, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Nathalie Sumien
- Center for Neuroscience Discovery, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Michael Forster
- Center for Neuroscience Discovery, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - James W Simpkins
- Department of Physiology and Pharmacology, Center for Neuroscience, Health Science Center, West Virginia University, Medical Center Drive, Morgantown, WV 26506, USA
| | - Ran Liu
- Center for Neuroscience Discovery, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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17
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Zhu Y, Chen Z, Chen X, Hu S. Serum sEPCR levels are elevated in patients with Alzheimer's disease. Am J Alzheimers Dis Other Demen 2015; 30:517-21. [PMID: 25588409 PMCID: PMC10852812 DOI: 10.1177/1533317514567124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Blood-brain barrier impairment and endothelial cell dysfunction have both been implicated in the pathogenesis of Alzheimer's disease (AD). The presence of vascular risk factors is also known to increase the risk of AD. Soluble endothelial protein C receptor (sEPCR) should thus produce procoagulant and proinflammatory effects. Serum sEPCR levels have been found to be associated with several diseases. To date, no reports have been published regarding serum sEPCR levels in AD. In this study, we found that serum sEPCR levels were significantly increased in patients with AD when compared to control participants (P = .0005). There was no significant difference between patients with mild cognitive impairment (MCI) and healthy controls (P = .055) or between patients with AD and MCI (P = .054). Importantly, our results also indicate that the degree of cognitive impairment is significantly correlated with serum sEPCR levels in all patients and healthy controls. These findings suggest that serum sEPCR levels could be a potential candidate for a biomarker panel for AD diagnosis.
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Affiliation(s)
- Yongjian Zhu
- Department of Rehabilitation, Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Huangshi, China
| | - Zhilong Chen
- Department of Gerontology, Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Huangshi, China
| | - Xugang Chen
- Department of Neurosurgery, the People's Hospital of Daye City, Daye, China
| | - Sheng Hu
- Department of Neurosurgery, Huangshi Central Hospital, Affiliated Hospital of Hubei Polytechnic University, Huangshi, China
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18
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Watson D, Castaño E, Kokjohn TA, Kuo YM, Lyubchenko Y, Pinsky D, Connolly ES, Esh C, Luehrs DC, Stine WB, Rowse LM, Emmerling MR, Roher AE. Physicochemical characteristics of soluble oligomeric Aβand their pathologic role in Alzheimer's disease. Neurol Res 2013; 27:869-81. [PMID: 16354549 DOI: 10.1179/016164105x49436] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Extracellular fibrillar amyloid deposits are prominent and universal Alzheimer's disease (AD) features, but senile plaque abundance does not always correlate directly with the degree of dementia exhibited by AD patients. The mechanism(s) and dynamics of Abeta fibril genesis and deposition remain obscure. Enhanced Abeta synthesis rates coupled with decreased degradative enzyme production and accumulating physical modifications that dampen proteolysis may all enhance amyloid deposit formation. Amyloid accumulation may indirectly exert the greatest pathologic effect on the brain vasculature by destroying smooth muscle cells and creating a cascade of negative impacts on cerebral blood flow. The most visible manifestation of amyloid dis-equilibrium could actually be a defense mechanism employed to avoid serious vascular wall degradation while the major toxic effects to the gray and white matter neurons are mediated by soluble oligomeric Abeta peptides with high beta-sheet content. The recognition that dynamic soluble oligomeric Abeta pools exist in AD and are correlated to disease severity led to neurotoxicity and physical conformation studies. It is now recognized that the most basic soluble Abeta peptides are stable dimers with hydrophobic regions sequestered from the aqueous environment and are capable of higher order aggregations. Time course experiments employing a modified ELISA method able to detect Abeta oligomers revealed dynamic intermolecular interactions and additional experiments physically confirmed the presence of stable amyloid multimers. Amyloid peptides that are rich in beta-sheet structure are capable of creating toxic membrane ion channels and a capacity to self-assemble as annular structures was confirmed in vitro using atomic force microscopy. Biochemical studies have established that soluble Abeta peptides perturb metabolic processes, provoke release of deleterious reactive compounds, reduce blood flow, induce mitochondrial apoptotic toxicity and inhibit angiogenesis. While there is no question that gross amyloid deposition does contribute to AD pathology, the destructive potential now associated with soluble Abeta suggests that treatment strategies that target these molecules may be efficacious in preventing some of the devastating effects of AD.
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Affiliation(s)
- Desiree Watson
- Pfizer, Global Research and Development, Ann Arbor, MI 48106 USA
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19
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Ruiz A, Pesini P, Espinosa A, Pérez-Grijalba V, Valero S, Sotolongo-Grau O, Alegret M, Monleón I, Lafuente A, Buendía M, Ibarria M, Ruiz S, Hernández I, San José I, Tárraga L, Boada M, Sarasa M. Blood amyloid beta levels in healthy, mild cognitive impairment and Alzheimer's disease individuals: replication of diastolic blood pressure correlations and analysis of critical covariates. PLoS One 2013; 8:e81334. [PMID: 24312290 PMCID: PMC3842353 DOI: 10.1371/journal.pone.0081334] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/14/2013] [Indexed: 01/03/2023] Open
Abstract
Plasma amyloid beta (Aβ) levels are being investigated as potential biomarkers for Alzheimer's disease. In AB128 cross-sectional study, a number of medical relevant correlates of blood Aβ40 or Aβ42 were analyzed in 140 subjects (51 Alzheimer's disease patients, 53 healthy controls and 36 individuals diagnosed with mild cognitive impairment). We determined the association between multiple variables with Aβ40 and Aβ42 levels measured in three different blood compartments called i) Aβ directly accessible (DA) in the plasma, ii) Aβ recovered from the plasma matrix (RP) after diluting the plasma sample in a formulated buffer, and iii) associated with the remaining cellular pellet (CP). We confirmed that diastolic blood pressure (DBP) is consistently correlated with blood DA Aβ40 levels (r=-0.19, P=0.032). These results were consistent in the three phenotypic groups studied. Importantly, the observation resisted covariation with age, gender or creatinine levels. Observed effect size and direction of Aβ40 levels/DBP correlation are in accordance with previous reports. Of note, DA Aβ40 and the RP Aβ40 were also strongly associated with creatinine levels (r=0.599, P<<0.001) and to a lesser extent to urea, age, hematocrit, uric acid and homocysteine (p<0.001). DBP and the rest of statistical significant correlates identified should be considered as potential confounder factors in studies investigating blood Aβ levels as potential AD biomarker. Remarkably, the factors affecting Aβ levels in plasma (DA, RP) and blood cell compartments (CP) seem completely different.
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Affiliation(s)
- Agustín Ruiz
- Alzheimer Research Center and Memory Clinic, Fundació ACE, Institut Català de Neurociències Aplicades, Barcelona, Spain
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20
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Amiri H, Saeidi K, Borhani P, Manafirad A, Ghavami M, Zerbi V. Alzheimer's disease: pathophysiology and applications of magnetic nanoparticles as MRI theranostic agents. ACS Chem Neurosci 2013; 4:1417-29. [PMID: 24024702 PMCID: PMC3837373 DOI: 10.1021/cn4001582] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 09/05/2013] [Indexed: 11/29/2022] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia. During the recent decade, nanotechnology has been widely considered, as a promising tool, for theranosis (diagnosis and therapy) of AD. Here we first discuss pathophysiology and characteristics of AD with a focus on the amyloid cascade hypothesis. Then magnetic nanoparticles (MNPs) and recent works on their applications in AD, focusing on the superparamagnetic iron oxide nanoparticles (SPIONs), are reviewed. Furthermore, the amyloid-nanoparticle interaction is highlighted, with the scope to be highly considered by the scientists aiming for diagnostics and/or treatment of AD employing nanoparticles. Furthermore, recent findings on the "ignored" parameters (e.g., effect of protein "corona" at the surface of nanoparticles on amyloid-β (Aβ) fibrillation process) are discussed.
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Affiliation(s)
- Houshang Amiri
- Department of Radiology and Department
of Anatomy, Donders Institute for Brain,
Cognition and Behaviour, Radboud University
Nijmegen Medical Centre, 6500HB Nijmegen, The Netherlands
| | - Kolsoum Saeidi
- Department of Medical Genetics and Department of Radiological
Sciences, Kerman University of Medical Sciences, 7618747653 Kerman, Iran
| | - Parvin Borhani
- Department of Medical Genetics and Department of Radiological
Sciences, Kerman University of Medical Sciences, 7618747653 Kerman, Iran
| | - Arash Manafirad
- National Cell Bank, Pasteur Institute of Iran, 13164 Tehran, Iran
| | - Mahdi Ghavami
- National Cell Bank, Pasteur Institute of Iran, 13164 Tehran, Iran
| | - Valerio Zerbi
- Department of Radiology and Department
of Anatomy, Donders Institute for Brain,
Cognition and Behaviour, Radboud University
Nijmegen Medical Centre, 6500HB Nijmegen, The Netherlands
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21
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Donix M, Scharf M, Marschner K, Werner A, Sauer C, Gerner A, Nees JA, Meyer S, Donix KL, Von Kummer R, Holthoff VA. Cardiovascular risk and hippocampal thickness in Alzheimer's disease. Int J Alzheimers Dis 2013; 2013:108021. [PMID: 24228185 PMCID: PMC3818844 DOI: 10.1155/2013/108021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Accepted: 09/10/2013] [Indexed: 11/18/2022] Open
Abstract
Cardiovascular risk factors influence onset and progression of Alzheimer's disease. Among cognitively healthy people, changes in brain structure and function associated with high blood pressure, diabetes, or other vascular risks suggest differential regional susceptibility to neuronal damage. In patients with Alzheimer's disease, hippocampal and medial temporal lobe atrophy indicate early neuronal loss preferentially in key areas for learning and memory. We wanted to investigate whether this regional cortical thinning would be modulated by cardiovascular risk factors. We utilized high-resolution magnetic resonance imaging and a cortical unfolding technique to determine the cortical thickness of medial temporal subregions in 30 patients with Alzheimer's disease. Cardiovascular risk was assessed using a sex-specific multivariable risk score. Greater cardiovascular risk was associated with cortical thinning in the hippocampus CA2/3/dentate gyrus area but not other hippocampal and medial temporal subregions. APOE genotype, a family history of Alzheimer's disease, and age did not influence cortical thickness. Alzheimer's disease-related atrophy could mask the influence of genetic risk factors or age on regional cortical thickness in medial temporal lobe regions, whereas the impact of vascular risk factors remains detectable. This highlights the importance of cardiovascular disease prevention and treatment in patients with Alzheimer's disease.
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Affiliation(s)
- Markus Donix
- Department of Psychiatry and Psychotherapy, Division of Old Age Psychiatry and Cognitive Neuropsychiatry, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE), 01307 Dresden, Germany
| | - Maria Scharf
- Department of Psychiatry and Psychotherapy, Division of Old Age Psychiatry and Cognitive Neuropsychiatry, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE), 01307 Dresden, Germany
| | - Kira Marschner
- Department of Psychiatry and Psychotherapy, Division of Old Age Psychiatry and Cognitive Neuropsychiatry, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE), 01307 Dresden, Germany
| | - Annett Werner
- Department of Neuroradiology, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Cathrin Sauer
- Department of Psychiatry and Psychotherapy, Division of Old Age Psychiatry and Cognitive Neuropsychiatry, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Antje Gerner
- Department of Psychiatry and Psychotherapy, Division of Old Age Psychiatry and Cognitive Neuropsychiatry, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE), 01307 Dresden, Germany
| | - Josef A. Nees
- Department of Psychiatry and Psychotherapy, Division of Old Age Psychiatry and Cognitive Neuropsychiatry, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Shirin Meyer
- Department of Psychiatry and Psychotherapy, Division of Old Age Psychiatry and Cognitive Neuropsychiatry, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Katharina L. Donix
- Department of Psychiatry and Psychotherapy, Division of Old Age Psychiatry and Cognitive Neuropsychiatry, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Rüdiger Von Kummer
- Department of Neuroradiology, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
| | - Vjera A. Holthoff
- Department of Psychiatry and Psychotherapy, Division of Old Age Psychiatry and Cognitive Neuropsychiatry, University Hospital Carl Gustav Carus, Technische Universität Dresden, 01307 Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE), 01307 Dresden, Germany
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22
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Glodzik L, Randall C, Rusinek H, de Leon MJ. Cerebrovascular reactivity to carbon dioxide in Alzheimer's disease. J Alzheimers Dis 2013; 35:427-40. [PMID: 23478306 DOI: 10.3233/jad-122011] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
There is growing evidence that cerebrovascular reactivity to carbon dioxide (CVRCO2) is impaired in Alzheimer's disease (AD). Preclinical and animal studies suggest chronic hypercontractility in brain vessels in AD. We review (a) preclinical studies of mechanisms for impaired CVRCO2 in AD; (b) clinical studies of cerebrovascular function in subjects with AD dementia, mild cognitive impairment (MCI), and normal cognition. Although results of clinical studies are inconclusive, an increasing number of reports reveal an impairment of vascular reactivity to carbon dioxide in subjects with AD, and possibly also in MCI. Thus, CVRCO2 may be an attractive means to detect an early vascular dysfunction in subjects at risk.
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Affiliation(s)
- Lidia Glodzik
- Center for Brain Health, Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA.
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23
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Paris D, Humphrey J, Quadros A, Patel N, Crescentini R, Crawford F, Mullan M. Vasoactive effects of Aβin isolated human cerebrovessels and in a transgenic mouse model of Alzheimer's disease: Role of inflammation. Neurol Res 2013; 25:642-51. [PMID: 14503019 DOI: 10.1179/016164103101201940] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
A beta peptides are the major protein constituents of Alzheimer's disease (AD) senile plaques and also form some deposits in the cerebrovasculature leading to cerebral amyloid angiopathy and hemorrhagic stroke. Functional vascular abnormalities are one of the earlier clinical manifestations in both sporadic and familial forms of AD. Most of the cardiovascular risk factors (for instance, diabetes, hypertension, high cholesterol levels, atherosclerosis and smoking) constitute risk factors for AD as well, suggesting that functional vascular abnormalities may contribute to AD pathology. We studied the effect of A beta on endothelin-1 induced vasoconstriction in isolated human cerebral arteries collected following rapid autopsies. We report that freshly solubilized A beta enhances endothelin-1 induced vasoconstriction in isolated human middle cerebral and basilar arteries. The vasoactive effect of A beta in these large human cerebral arteries is inhibited by NS-398, a selective cyclooxygenase-2 inhibitor and by SB202190, a specific p38 Mitogen Activated Protein Kinase inhibitor suggesting the involvement of a pro-inflammatory pathway. Using a scanner laser Doppler imager, we observed that cerebral blood flow is decreased in the double transgenic APPsw Alzheimer mouse (PS1/APPsw) compared to PS1 littermates and can be improved by chronic treatment with either NS-398 or SB202190. Altogether, our data suggest a link between inflammation and the compromised cerebral hemodynamics in AD.
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Affiliation(s)
- Daniel Paris
- Roskamp Institute, 2040 Whitfield Avenue, Sarasota, FL 34243, USA.
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Abrahamson EE, Foley LM, Dekosky ST, Hitchens TK, Ho C, Kochanek PM, Ikonomovic MD. Cerebral blood flow changes after brain injury in human amyloid-beta knock-in mice. J Cereb Blood Flow Metab 2013; 33:826-33. [PMID: 23443172 PMCID: PMC3677107 DOI: 10.1038/jcbfm.2013.24] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Traumatic brain injury (TBI) is an environmental risk factor for Alzheimer's disease (AD). Increased brain concentrations of amyloid-β (Aβ) peptides and impaired cerebral blood flow (CBF) are shared pathologic features of TBI and AD and promising therapeutic targets. We used arterial spin-labeling magnetic resonance imaging to examine if CBF changes after TBI are influenced by human Aβ and amenable to simvastatin therapy. CBF was measured 3 days and 3 weeks after controlled cortical impact (CCI) injury in transgenic human Aβ-expressing APP(NLh/NLh) mice compared to murine Aβ-expressing C57Bl/6J wild types. Compared to uninjured littermates, CBF was reduced in the cortex of the injured hemisphere in both Aβ transgenics and wild types; deficits were more pronounced in the transgenic group, which exhibited injury-induced increased concentrations of human Aβ. In the hemisphere contralateral to CCI, CBF levels were stable in Aβ transgenic mice but increased in wild-type mice, both relative to uninjured littermates. Post-injury treatment of Aβ transgenic mice with simvastatin lowered brain Aβ concentrations, attenuated deficits in CBF ipsilateral to injury, restored hyperemia contralateral to injury, and reduced brain tissue loss. Future studies examining long-term effects of simvastatin therapy on CBF and chronic neurodegenerative changes after TBI are warranted.
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Affiliation(s)
- Eric E Abrahamson
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Effect of bFGF on neuronal damage induced by sequential treatment of amyloid β and excitatory amino acid in vitro and in vivo. Eur J Pharmacol 2012; 695:76-82. [DOI: 10.1016/j.ejphar.2012.09.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 09/04/2012] [Accepted: 09/17/2012] [Indexed: 11/18/2022]
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Alzheimer disease as a vascular disorder: Where do mitochondria fit? Exp Gerontol 2012; 47:878-86. [DOI: 10.1016/j.exger.2012.07.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 07/12/2012] [Accepted: 07/13/2012] [Indexed: 12/26/2022]
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Petzold GC, Murthy VN. Role of astrocytes in neurovascular coupling. Neuron 2011; 71:782-97. [PMID: 21903073 DOI: 10.1016/j.neuron.2011.08.009] [Citation(s) in RCA: 285] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2011] [Indexed: 10/17/2022]
Abstract
Neural activity is intimately tied to blood flow in the brain. This coupling is specific enough in space and time that modern imaging methods use local hemodynamics as a measure of brain activity. In this review, we discuss recent evidence indicating that neuronal activity is coupled to local blood flow changes through an intermediary, the astrocyte. We highlight unresolved issues regarding the role of astrocytes and propose ways to address them using novel techniques. Our focus is on cellular level analysis in vivo, but we also relate mechanistic insights gained from ex vivo experiments to native tissue. We also review some strategies to harness advances in optical and genetic methods to study neurovascular coupling in the intact brain.
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Affiliation(s)
- Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
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28
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Si ML, Long C, Chen MF, Lee TJF. Estrogen prevents β-amyloid inhibition of sympathetic α7-nAChR-mediated nitrergic neurogenic dilation in porcine basilar arteries. Acta Physiol (Oxf) 2011; 203:13-23. [PMID: 21073661 DOI: 10.1111/j.1748-1716.2010.02224.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
AIM β-amyloid peptides (Aβs) have been shown to block cerebral nitrergic neurogenic vasodilation by blocking sympathetic α7-nAChRs, and that oestrogen prevents Aβ-induced neurotoxicity. We examined whether Aβ-inhibition of α7-nAChR-mediated cerebral nitrergic vasodilation was prevented by oestrogen. METHODS Effects of Aβ and 17β-oestradiol on neurogenic nitrergic vasodilation in isolated porcine basilar arteries were examined using wire-myography. Drug effects on nicotine- and choline-induced calcium influx and inward currents in porcine cultured superior cervical ganglion (SCG) were investigated using confocal microscopy and patch-clamp techniques respectively. RESULTS Precontracted endothelium-denuded basilar arteries relaxed exclusively upon transmural nerve stimulation (TNS, 8 Hz), and applications of nicotine (100 μm) or choline (1 mm), which was sensitive to nitro-L-arginine (L-NNA, 30 μm) and tetrodotoxin (0.3 μm). The relaxation induced by nicotine and choline but not that by TNS was blocked reversibly by Aβ(1-40) in a concentration-dependent manner. Aβ(1-40) also reversibly blocked nicotine- and choline-induced increase of calcium influx and inward currents in the SCG neurons. Aβ inhibition of nicotine- and choline-induced α7-nAChR-mediated nitrergic vasodilation and inward currents was prevented by 17β-oestradiol (10 μm), but not by α-oestradiol (10 μm) or testosterone (10 μm). CONCLUSION These results provide further evidence supporting that Aβ is an antagonist for the α7-nAChR found on post-ganglionic sympathetic adrenergic nerve terminals originating in the SCG. Aβ can cause constriction of cerebral arteries with possible decreased regional cerebral blood flow by blocking sympathetic nerve-mediated release of nitric oxide from the perivascular nitrergic nerves. This effect of Aβ can be prevented by endogenous oestrogen but not testosterone.
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Affiliation(s)
- M-L Si
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, USA
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29
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Prvulovic D, Bokde ALW, Faltraco F, Hampel H. Functional magnetic resonance imaging as a dynamic candidate biomarker for Alzheimer's disease. Prog Neurobiol 2011; 95:557-69. [PMID: 21722703 DOI: 10.1016/j.pneurobio.2011.05.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 05/24/2011] [Accepted: 05/27/2011] [Indexed: 11/18/2022]
Abstract
During the last two decades, imaging of neural activation has become an invaluable tool for assessing the functional organization of the human brain in vivo. Due to its widespread application in neuroscience, functional neuroimaging has raised the interest of clinical researchers in its possible use as a diagnostic biomarker. A hallmark feature of many neurodegenerative diseases is their chronic non-linear dynamic and highly complex preclinical course. Neurodegenerative diseases unfold over years to decades through clinically silent and asymptomatic stages of early adaptive, compensatory to pathophysiological (i.e. actively neurodegenerative) and decompensatory mechanisms in the brain - phases that are increasingly being considered as critical for primary and secondary preventive and therapeutic measures. Emerging evidence supports the concept of a potentially fully reversible functional phase that may precede the onset of micro- and macrostructural and cognitive decline, a potentially late-stage "neurodegenerative" phase of a primary neurodegenerative disorder. Alzheimer's disease serves as an ideal model to test this hypothesis supported by the neural network model of the healthy and diseased brain. Being highly dynamic in nature, brain activation and neuronal network functional connectivity represent not only candidate diagnostic but also candidate surrogate markers for interventional trials. Potential caveats of functional imaging are critically reviewed with focus on confound variables such as altered neurovascular coupling as well as parameters related to task- and study design.
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Affiliation(s)
- David Prvulovic
- Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Goethe-University of Frankfurt, Frankfurt, Germany.
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Lee RHC, Liu YQ, Chen PY, Liu CH, Chen MF, Lin HW, Kuo JS, Premkumar LS, Lee TJF. Sympathetic α₃β₂-nAChRs mediate cerebral neurogenic nitrergic vasodilation in the swine. Am J Physiol Heart Circ Physiol 2011; 301:H344-54. [PMID: 21536845 DOI: 10.1152/ajpheart.00172.2011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The α(7)-nicotinic ACh receptor (α(7)-nAChR) on sympathetic neurons innervating basilar arteries of pigs crossed bred between Landrace and Yorkshire (LY) is known to mediate nicotine-induced, β-amyloid (Aβ)-sensitive nitrergic neurogenic vasodilation. Preliminary studies, however, demonstrated that nicotine-induced cerebral vasodilation in pigs crossbred among Landrace, Yorkshire, and Duroc (LYD) was insensitive to Aβ and α-bungarotoxin (α-BGTX). We investigated nAChR subtype on sympathetic neurons innervating LYD basilar arteries. Nicotine-induced relaxation of porcine isolated basilar arteries was examined by tissue bath myography, inward currents on nAChR-expressing oocytes by two-electrode voltage recording, and mRNA and protein expression in the superior cervical ganglion (SCG) and middle cervical ganglion (MCG) by reverse transcription PCR and Western blotting. Nicotine-induced basilar arterial relaxation was not affected by Aβ, α-BGTX, and α-conotoxin IMI (α(7)-nAChR antagonists), or α-conotoxin AuIB (α(3)β(4)-nAChR antagonist) but was inhibited by tropinone and tropane (α(3)-containing nAChR antagonists) and α-conotoxin MII (selective α(3)β(2)-nAChR antagonist). Nicotine-induced inward currents in α(3)β(2)-nAChR-expressing oocytes were inhibited by α-conotoxin MII but not by α-BGTX, Aβ, or α-conotoxin AuIB. mRNAs of α(3)-, α(7)-, β(2)-, and β(4)-subunits were expressed in both SCGs and MCGs with significantly higher mRNAs of α(3)-, β(2)-, and β(4)-subunits than that of α(7)-subunit. The Aβ-insensitive sympathetic α(3)β(2)-nAChR mediates nicotine-induced cerebral nitrergic neurogenic vasodilation in LYD pigs. The different finding from Aβ-sensitive α(7)-nAChR in basilar arteries of LY pigs may offer a partial explanation for different sensitivities of individuals to Aβ in causing diminished cerebral nitrergic vasodilation in diseases involving Aβ.
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Affiliation(s)
- Reggie Hui-Chao Lee
- Institutes of Medical Sciences, College of Medicine, Tzu Chi University, Hualien, Taiwan
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31
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Lambert JC, Dallongeville J, Ellis KA, Schraen-Maschke S, Lui J, Laws S, Dumont J, Richard F, Cottel D, Berr C, Ames D, Masters CL, Rowe CC, Szoeke C, Tzourio C, Dartigues JF, Buée L, Martins R, Amouyel P. Association of plasma Aß peptides with blood pressure in the elderly. PLoS One 2011; 6:e18536. [PMID: 21525986 PMCID: PMC3078119 DOI: 10.1371/journal.pone.0018536] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 03/03/2011] [Indexed: 01/10/2023] Open
Abstract
Background Aß peptides are often considered as catabolic by-products of the amyloid ß protein precursor (APP), with unknown physiological functions. However, several biological properties have been tentatively attributed to these peptides, including a role in vasomotion. We assess whether plasma Aß peptide levels might be associated with systolic and diastolic blood pressure values (SBP and DBP, respectively). Methodology/Principal Findings Plasma Aß1-40 and Aß1-42 levels were measured using an xMAP-based assay in 1,972 individuals (none of whom were taking antihypertensive drugs) from 3 independent studies: the French population-based 3C and MONA-LISA (Lille) studies (n = 627 and n = 769, respectively) and the Australian, longitudinal AIBL study (n = 576). In the combined sample, the Aß1-42/ Aß1-40 ratio was significantly and inversely associated with SBP (p = 0.03) and a similar trend was observed for DBP (p = 0.06). Using the median age (69) as a cut-off, the Aß1-42/Aß1-40 ratio was strongly associated with both SBP and DBP in elderly individuals (p = 0.002 and p = 0.03, respectively). Consistently, a high Aß1-42/ Aß1-40 ratio was associated with a lower risk of hypertension in both the combined whole sample (odds ratio [OR], 0.71; 95% confidence interval [CI], 0.56-0.90) and (to an even greater extent) in the elderly subjects (OR, 0.53; 95% CI, 0.37–0.75). Lastly, all these associations appeared to be primarily driven by the level of plasma Aß1-40. Conclusion The plasma Aß1-42/Aß1-40 ratio is inversely associated with SBP, DBP and the risk of hypertension in elderly subjects, suggesting that Aß peptides affect blood pressure in vivo. These results may be particularly relevant in Alzheimer's disease, in which a high Aß1-42/Aß1-40 plasma ratio is reportedly associated with a decreased risk of incident disease.
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Palmer J, Love S. Endothelin receptor antagonists: potential in Alzheimer's disease. Pharmacol Res 2010; 63:525-31. [PMID: 21193044 DOI: 10.1016/j.phrs.2010.12.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 12/17/2010] [Accepted: 12/17/2010] [Indexed: 12/20/2022]
Abstract
Alzheimer's disease (AD) is believed to be initiated by the accumulation of neurotoxic forms of Aβ peptide within the brain. AD patients show reduction of cerebral blood flow (CBF), the extent of the reduction correlating with the impairment of cognition. There is evidence that cerebral hypoperfusion precedes and may even trigger the onset of dementia in AD. Cerebral hypoperfusion impairs neuronal function, reduces the clearance of Aβ peptide and other toxic metabolites from the brain, and upregulates Aβ production. Studies in animal models of AD have shown the reduction in CBF to be more than would be expected for the reduction in neuronal metabolic activity. Aβ may contribute to the reduction in CBF in AD, as both Aβ₁₋₄₀ and Aβ₁₋₄₂ induce cerebrovascular dysfunction. Aβ₁₋₄₀ acts directly on cerebral arteries to cause cerebral smooth muscle cell contraction. Aβ₁₋₄₂ causes increased neuronal production and release of endothelin-1 (ET-1), a potent vasoconstrictor, and upregulation of endothelin-converting enzyme-2 (ECE-2), the enzyme which cleaves ET-1 from its inactive precursor. ET-1 and ECE-2 are also elevated in AD, making it likely that upregulation of the ECE-2-ET-1 axis by Aβ₁₋₄₂ contributes to the chronic reduction of CBF in AD. At present, only a few symptomatic treatment options exist for AD. The involvement of ET-1 in the pathogenesis of endothelial dysfunction associated with elevated Aβ indicates the potential for endothelin receptor antagonists in the treatment of AD. It has already been demonstrated that the endothelin receptor antagonist bosentan, preserves aortic and carotid endothelial function in Tg2576 mice, and our findings suggest that endothelin receptor antagonists may be beneficial in maintaining CBF in AD.
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Affiliation(s)
- Jennifer Palmer
- Dementia Research Group, Institute of Clinical Neurosciences, School of Clinical Sciences, University of Bristol, Frenchay Hospital, Bristol BS16 1LE, United Kingdom.
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33
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Yavuz BB, Dede DS, Yavuz B, Cankurtaran M, Halil M, Ulger Z, Cankurtaran ES, Aytemir K, Kabakci G, Haznedaroglu IC, Ariogul S. Potential biomarkers for vascular damage in Alzheimer's disease: thrombomodulin and von Willebrand factor. J Nutr Health Aging 2010; 14:439-41. [PMID: 20617285 DOI: 10.1007/s12603-010-0043-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
OBJECTIVES Evidence regarding the vascular basis of Alzheimer's disease (AD) is growing. In vascular damage thrombomodulin tears of the cell wall and its level increases in the plasma. von Willebrand factor (vWF) is also thought to be a biomarker for vascular damage. The aim of this study was to examine the levels of vWF and thrombomodulin in AD as possible markers for vascular damage and to test their utility as an early biomarker in AD. DESIGN Case-control study. SETTING Geriatric medicine outpatient clinic of a university hospital. PARTICIPANTS Twenty Alzheimer's disease patients free from vascular risk factors and 20 controls were enrolled in the study. MEASUREMENTS Thrombomodulin and VWF levels of 20 AD patients and 20 controls were analyzed by commercial kits. RESULTS Thrombomodulin levels were not different between Alzheimer's disease and control groups [median (range) = 4.25 (2.27-37.00) ng/ml in Alzheimer's disease and 3.55 (2.27-14.00) in control group, p=0.15]. Von Willebrand Factor antigen (%) levels were 188.5 (96-306) in Alzheimer's disease, and 181 (112- 284) in control group (p=0.74). CONCLUSION Although vascular damage is thought to play role in the pathogenesis of AD, vWF and thrombomodulin failed to demonstrate the vascular damage in AD. Their utility to be used as early biomarkers of AD could not be shown.
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Affiliation(s)
- B B Yavuz
- Hacettepe University, Faculty of Medicine, Department of Internal Medicine, Division of Geriatric Medicine, Sihhiye, 06100, Ankara, Turkey.
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Palmer JC, Kehoe PG, Love S. Endothelin-converting enzyme-1 in Alzheimer's disease and vascular dementia. Neuropathol Appl Neurobiol 2010; 36:487-97. [DOI: 10.1111/j.1365-2990.2010.01084.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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35
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Hsu MJ, Sheu JR, Lin CH, Shen MY, Hsu CY. Mitochondrial mechanisms in amyloid beta peptide-induced cerebrovascular degeneration. Biochim Biophys Acta Gen Subj 2010; 1800:290-6. [DOI: 10.1016/j.bbagen.2009.08.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 08/06/2009] [Accepted: 08/11/2009] [Indexed: 01/19/2023]
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36
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Cole SL, Vassar R. Linking vascular disorders and Alzheimer's disease: potential involvement of BACE1. Neurobiol Aging 2009; 30:1535-44. [PMID: 18289733 PMCID: PMC3490488 DOI: 10.1016/j.neurobiolaging.2007.12.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 11/28/2007] [Accepted: 12/14/2007] [Indexed: 01/26/2023]
Abstract
The etiology of Alzheimer's disease (AD) remains unknown. However, specific risk factors have been identified, and aging is the strongest AD risk factor. The majority of cardiovascular events occur in older people and a close relationship between vascular disorders and AD exists. Amyloid plaques, composed of the beta amyloid peptide (Abeta), are hallmark lesions in AD and evidence indicates that Abeta plays a central role in AD pathophysiology. The BACE1 enzyme is essential for Abeta generation, and BACE1 levels are elevated in AD brain. The cause(s) of this BACE1 elevation remains undetermined. Here we review the potential contribution of vascular disease to AD pathogenesis. We examine the putative vasoactive properties of Abeta and how the cellular changes associated with vascular disease may elevate BACE1 levels. Despite increasing evidence, the exact role(s) vascular disorders play in AD remains to be determined. However, given that vascular diseases can be addressed by lifestyle and pharmacologic interventions, the potential benefits of these therapies in delaying the clinical appearance and progression of AD may warrant investigation.
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Affiliation(s)
- Sarah L Cole
- Northwestern University, The Feinberg School of Medicine, Department of Cell and Molecular Biology, 303 E. Chicago Avenue, Chicago, IL 60611, USA.
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37
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Kaminsky YG, Marlatt MW, Smith MA, Kosenko EA. Subcellular and metabolic examination of amyloid-beta peptides in Alzheimer disease pathogenesis: evidence for Abeta(25-35). Exp Neurol 2009; 221:26-37. [PMID: 19751725 DOI: 10.1016/j.expneurol.2009.09.005] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 09/03/2009] [Accepted: 09/04/2009] [Indexed: 11/28/2022]
Abstract
Amyloid-beta peptide (Abeta) is a central player in the pathogenesis and diagnosis of Alzheimer disease. It aggregates to form the core of Alzheimer disease-associated plaques found in coordination with tau deposits in diseased individuals. Despite this clinical relevance, no single hypothesis satisfies and explicates the role of Abeta in toxicity and progression of the disease. To explore this area, investigators have focused on mechanisms of cellular dysfunction, aggregation, and maladaptive responses. Extensive research has been conducted using various methodologies to investigate Abeta peptides and oligomers, and these multiple facets have provided a wealth of data from specific models. Notably, the utility of each experiment must be considered in regards to the brain environment. The use of Abeta(25-35) in studies of cellular dysfunction has provided data indicating that the peptide is indeed responsible for multiple disturbances to cellular integrity. We will review how Abeta peptide induces oxidative stress and calcium homeostasis, and how multiple enzymes are deleteriously impacted by Abeta(25-35). Understanding and discussing the origin and properties of Abeta peptides is essential to evaluating their effects on various intracellular metabolic processes. Attention will also be specifically directed to metabolic compartmentation in affected brain cells, including mitochondrial, cytosolic, nuclear, and lysosomal enzymes.
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Affiliation(s)
- Yury G Kaminsky
- Institute of Theoretical and Experimental Biophysics, RAS, Pushchino, Russia.
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38
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Abstract
Cumulative evidence implicates hypertension in the pathogenesis of Alzheimer disease. Although it may not presently be possible to completely differentiate the effects of treatment and control of hypertension itself from those of the medication used to achieve such treatment goals, efforts directed at the treatment and control of hypertension can have significant public health impact.
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Affiliation(s)
- Thomas Olabode Obisesan
- Division of Geriatrics, Department of Medicine, Howard University Hospital, 2041 Georgia Avenue, NW, Washington, DC 20060, USA.
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39
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Palmer JC, Baig S, Kehoe PG, Love S. Endothelin-converting enzyme-2 is increased in Alzheimer's disease and up-regulated by Abeta. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 175:262-70. [PMID: 19541930 DOI: 10.2353/ajpath.2009.081054] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Alzheimer's disease (AD) is thought to be caused by the accumulation of amyloid beta (Abeta) peptide within the brain. Endothelin-converting enzyme-2 (ECE-2), which is expressed in neural tissues, cleaves 'big endothelin' to produce the vasoconstrictor endothelin-1. ECE-2 also degrades Abeta. We have examined ECE-2 expression in the temporal cortex of brain tissue from patients with AD, vascular dementia, and controls. Immunohistochemistry with specific antibodies showed ECE-2 to be abundant within pyramidal neurons in both the hippocampus and neocortex, but also to be present in certain astrocytes and microglia, particularly in AD brains. Quantitative real-time PCR showed ECE-2 mRNA to be markedly elevated in AD but not in vascular dementia. ECE-2 protein concentration, measured by sandwich enzyme-linked immunosorbent assay, was also significantly elevated in AD but not in vascular dementia. Exposure of SH-SY5Y human neuroblastoma cells to monomeric or oligomeric Abeta(1-42) caused an initial decrease in ECE-2 mRNA at 4 hours, but a marked increase by 24 hours. Our findings indicate that Abeta accumulation in AD is unlikely to be caused by ECE-2 deficiency. However, ECE-2 expression is up-regulated, perhaps to minimize Abeta accumulation, but this may also be a mechanism through which endothelin-1 production is increased and cerebral blood flow is reduced in AD. Our findings suggest that endothelin-1 receptor antagonists, already licensed for treating other diseases, could be of benefit in AD therapies.
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Affiliation(s)
- Jennifer C Palmer
- Dementia Research Group, Frenchay Hospital, Bristol, United Kingdom.
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40
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Hooijmans CR, Van der Zee CEEM, Dederen PJ, Brouwer KM, Reijmer YD, van Groen T, Broersen LM, Lütjohann D, Heerschap A, Kiliaan AJ. DHA and cholesterol containing diets influence Alzheimer-like pathology, cognition and cerebral vasculature in APPswe/PS1dE9 mice. Neurobiol Dis 2008; 33:482-98. [PMID: 19130883 DOI: 10.1016/j.nbd.2008.12.002] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Revised: 11/28/2008] [Accepted: 12/04/2008] [Indexed: 11/18/2022] Open
Abstract
Cholesterol and docosahexenoic acid (DHA) may affect degenerative processes in Alzheimer's Disease (AD) by influencing Abeta metabolism indirectly via the vasculature. We investigated whether DHA-enriched diets or cholesterol-containing Typical Western Diets (TWD) alter behavior and cognition, cerebral hemodynamics (relative cerebral blood volume (rCBV)) and Abeta deposition in 8- and 15-month-old APP(swe)/PS1(dE9) mice. In addition we investigated whether changes in rCBV precede changes in Abeta deposition or vice versa. Mice were fed regular rodent chow, a TWD-, or a DHA-containing diet. Behavior, learning and memory were investigated, and rCBV was measured using contrast-enhanced MRI. The Abeta load was visualized immunohistochemically. We demonstrate that DHA altered rCBV in 8-month-old APP/PS1 and wild type mice[AU1]. In 15-month-old APP/PS1 mice DHA supplementation improved spatial memory, decreased Abeta deposition and slightly increased rCBV, indicating that a DHA-enriched diet can diminish AD-like pathology. In contrast, TWD diets decreased rCBV in 15-month-old mice. The present data indicate that long-term dietary interventions change AD-like pathology in APP/PS1 mice. Additionally, effects of the tested diets on vascular parameters were observed before effects on Abeta load were noted. These data underline the importance of vascular factors in the APP/PS1 mouse model of AD pathology.
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Affiliation(s)
- C R Hooijmans
- Radboud University Nijmegen Medical Center, Donders Institute for Brain, Cognition and Behaviour, (department: Anatomy and Cognitive Neuroscience) Geert Grooteplein noord 21, PO BOX 9101, 6500 HB, Nijmegen, The Netherlands
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Hu NW, Smith IM, Walsh DM, Rowan MJ. Soluble amyloid-beta peptides potently disrupt hippocampal synaptic plasticity in the absence of cerebrovascular dysfunction in vivo. Brain 2008; 131:2414-24. [PMID: 18678563 DOI: 10.1093/brain/awn174] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Long before the onset of clinical Alzheimer's disease non-fibrillar, soluble assembly states of amyloid-beta (Abeta) peptides are believed to cause cognitive problems by disrupting synaptic function in the absence of significant neurodegeneration. Since many of the risk factors for Alzheimer's disease are vascular, impairment of cerebral blood flow by soluble Abeta has been proposed to be critical in triggering these early changes. However, it is not known if soluble Abeta can affect cerebrovascular function at the concentrations required to cause inhibition of synaptic plasticity mechanisms believed to underlie the early cognitive deficits of Alzheimer's disease. Here we developed a new method to simultaneously assess the ability of soluble Abeta to impair plasticity at synapses and to affect resting and activity-dependent local blood flow in the rat hippocampus in vivo. Intracerebroventricular injection of soluble synthetic Abeta(40) dimers rapidly inhibited plasticity of excitatory synaptic transmission at doses (10-42 pmol) comparable to natural Abeta, but failed to affect vascular function measured using laser-Doppler flowmetry (LDF). Like wild-type Abeta(40), the more vasculotropic Abeta produced by people with familial hemorrhagic stroke of the Dutch type (Abeta(40)E22Q), impaired hippocampal plasticity without causing a significant change in local blood flow. Furthermore, neither resting nor activation-evoked hippocampal perfusion was affected by soluble Abeta(42), even at a concentration that markedly (25%) reduced baseline synaptic transmission. These findings demonstrate that the putative synaptotoxic soluble Abeta species of early Alzheimer's disease cause synaptic dysfunction in the absence of detectible changes in local blood flow. This strongly indicates that early cognitive deficits can be caused by soluble Abeta independently of deleterious effects on cerebrovascular dynamics.
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Affiliation(s)
- Neng-Wei Hu
- Trinity College Institute of Neuroscience, Trinity College, Dublin, Ireland
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42
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Non-invasive characterization of β-amyloid1-40 vasoactivity by functional magnetic resonance imaging in mice. Neuroscience 2008; 155:263-9. [DOI: 10.1016/j.neuroscience.2008.04.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 03/14/2008] [Accepted: 04/03/2008] [Indexed: 11/20/2022]
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Smith CCT, Stanyer L, Betteridge DJ, Cooper MB. Native and oxidized low-density lipoproteins modulate the vasoactive actions of soluble β-amyloid peptides in rat aorta. Clin Sci (Lond) 2007; 113:427-34. [PMID: 17531005 DOI: 10.1042/cs20070082] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cerebrovascular accumulation of Aβ (β-amyloid) occurs in aging and AD (Alzheimer's disease). Hypercholesterolaemia, which is associated with raised plasma LDL (low-density lipoprotein), may predispose to AD. Soluble Aβ is found in the circulation and enhances vasoconstriction. Under conditions that may favour the formation of short Aβ oligomers, as opposed to more severe polymerization leading to Aβ fibrillogenesis, we investigated the influence of LDLs on the vasoactive actions of soluble Aβ. Thus the actions of Aβ40 and Aβ42 in combination with native or oxidized LDL on vasoconstriction to NA (noradrenaline) and vasodilatation to ACh (acetylcholine) were examined in rat aortic rings. LDL, particularly when oxidized, potentiated NA-induced constriction when combined with soluble Aβ40 and, especially, Aβ42. Soluble Aβ40 reduced relaxation induced by ACh, but Aβ42 was ineffective. Native and oxidized LDL also attenuated relaxation. Synergism occurred between oxidized LDL and Aβ with respect to ACh-induced relaxation, but not between native LDL and Aβ. We have shown for the first time that, under conditions that may result in Aβ oligomer formation, LDL, particularly when oxidized, modulates the vascular actions of soluble Aβ to extents greater than those reported previously for fibrillar Aβ preparations. Mechanisms whereby a treatable condition, namely hypercholesterolaemia, might contribute to the development of the cerebrovascular component of AD are indicated.
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Affiliation(s)
- Christopher C T Smith
- The Hatter Cardiovascular Institute, University College London Hospital and Medical School, 67 Chenies Mews, London WC1E 6HX, UK.
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Dede DS, Yavuz B, Yavuz BB, Cankurtaran M, Halil M, Ulger Z, Cankurtaran ES, Aytemir K, Kabakci G, Ariogul S. Assessment of endothelial function in Alzheimer's disease: is Alzheimer's disease a vascular disease? J Am Geriatr Soc 2007; 55:1613-7. [PMID: 17711428 DOI: 10.1111/j.1532-5415.2007.01378.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To compare endothelial function of people with Alzheimer's disease (AD) with that of people without. DESIGN Case-control study. SETTING Geriatric medicine outpatient clinic of a university hospital. PARTICIPANTS Twenty-five patients with AD who were free of vascular risk factors and 24 healthy elderly controls were enrolled. Exclusion criteria were diabetes mellitus, hypertension, dyslipidemia, evident stroke, smoking, documented coronary artery disease, history of myocardial infarction, heart failure, acute or chronic infection, malignancy, peripheral artery disease, renal disease, rheumatologic diseases, alcohol abuse, and certain drugs that may affect endothelial function. Both groups underwent comprehensive geriatric assessment and neuropsychiatric assessment. MEASUREMENTS Endothelial function was evaluated according to flow-mediated dilation (FMD) from the brachial artery. RESULTS Mean age +/- standard deviation was 78 +/- 5.9 in the group with AD (11 female and 14 male) and 72.1 +/- 5.8 in the control group (9 female and 11 male). Multiple linear regression analysis revealed that FMD was significantly lower in patients with AD (median 3.45, range 0-7) than controls (median 8.41, range 1-14) (P < .001), independent of age. It was also found that FMD values were inversely correlated with the stage of the disease as determined according to the Clinical Dementia Rating scale (r=-0.603, P < .001). CONCLUSION Endothelial function is impaired in patients with AD. Endothelial function was worse in patients with severe AD. These findings provide evidence that vascular factors have a role in the pathogenesis of AD.
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Affiliation(s)
- Didem Sener Dede
- Department of Internal Medicine, Haceteppe University, Ankara, Turkey
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Eder L, Zisman D, Wolf R, Bitterman H. Pulmonary hypertension and amyloidosis--an uncommon association: a case report and review of the literature. J Gen Intern Med 2007; 22:416-9. [PMID: 17356978 PMCID: PMC1824747 DOI: 10.1007/s11606-006-0052-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Only a limited number of patients with amyloidosis and pulmonary hypertension have been reported in the literature. We report a 73-year-old female with AL type amyloidosis who developed respiratory insufficiency and right heart failure because of severe pulmonary hypertension. There were no signs of cardiac involvement with amyloid or findings consistent with interstitial lung disease. Previous reports of pulmonary hypertension without an apparent parenchymal lung or myocardial involvement with amyloidosis are summarized. Pulmonary hypertension due to deposition of amyloid in the pulmonary vasculature is an uncommon finding; however, it should be considered in cases of unexplained pulmonary hypertension in patients with amyloidosis.
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Affiliation(s)
- Lihi Eder
- Department of Internal Medicine, Carmel Medical Center, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
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van Dijk EJ, Prins ND, Hofman A, van Duijn CM, Koudstaal PJ, Breteler MMB. Plasma beta amyloid and impaired CO2-induced cerebral vasomotor reactivity. Neurobiol Aging 2006; 28:707-12. [PMID: 16698128 DOI: 10.1016/j.neurobiolaging.2006.03.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Revised: 03/08/2006] [Accepted: 03/31/2006] [Indexed: 11/19/2022]
Abstract
Amyloid beta (Abeta) may disturb cerebral autoregulation by damaging the wall of small cerebral blood vessels and by direct negative vasoactive properties. We assessed whether previous and concurrent plasma Abeta(1-40) and Abeta(1-42) levels were associated with an impaired CO2-induced cerebral vasomotor response. In the longitudinal population-based Rotterdam Study we measured plasma Abeta levels and cerebral vasomotor reactivity to hypercapnia with transcranial Doppler ultrasonography (TCD) in 441 people, aged 60-90 years. We performed age and sex adjusted logistic regression analysis. Plasma Abeta levels assessed on average 6.5-year before TCD were linearly associated with an impaired CO2-induced cerebral vasomotor response (odds ratio 1.48 (95%CI 1.19;1.84) per standard deviation increase in Abeta(1-40), and 1.36 (95%CI 1.09;1.70) per standard deviation increase in Abeta(1-42)). Such an association was not present for Abeta assessed concurrently with the TCD measurement. Persons whose plasma Abeta(1-40) levels had decreased in the 6.5-year period preceding TCD measurements were more likely to have an impaired CO2-induced vasomotor reactivity. Overall our observations are most compatible with plasma Abeta levels representing vascular Abeta deposits years later resulting in impaired CO2-induced vasomotor reactivity.
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Affiliation(s)
- Ewoud J van Dijk
- Department of Epidemiology and Biostatistics, Erasmus MC, Erasmus University Medical Center, PO Box 1738, 3000 Rotterdam, The Netherlands
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Elesber AA, Bonetti PO, Woodrum JE, Zhu XY, Lerman LO, Younkin SG, Lerman A. Bosentan preserves endothelial function in mice overexpressing APP. Neurobiol Aging 2006; 27:446-50. [PMID: 15894408 DOI: 10.1016/j.neurobiolaging.2005.02.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2004] [Revised: 01/06/2005] [Accepted: 02/28/2005] [Indexed: 11/22/2022]
Abstract
This study was designed to test the hypothesis that Alzheimer's disease (AD) is associated with endothelial dysfunction and that chronic endothelin-1 antagonism preserves endothelial function in mice overexpressing the AD amyloid precursor protein (APP). Three groups of mice were studied: C57BL/6 (normal control, n = 6), transgenic mice overexpressing APP (Tg2576, n = 5), and Tg2576 mice fed Bosentan (100 mg/(kg day)(-1)), a combined endothelin A and B receptor antagonist, for 4 months (Tg2576+Bosentan, n = 5). Mice were sacrificed at the age of 7 months. In vitro, the endothelium-dependent aortic vasorelaxation was significantly attenuated in Tg2576 mice as compared to C57BL/6 and Tg2576+Bosentan mice. In contrast, Tg2576+Bosentan and C57BL/6 mice showed similar endothelium-dependent aortic vasorelaxation. Similarly, endothelium-dependent carotid vasorelaxation was significantly attenuated in Tg2576 mice compared to C57BL/6 and Tg2576+Bosentan mice. There was no difference between the three groups in the response to nitroprusside. The current study demonstrates the presence of endothelial dysfunction in both carotid and aortic arteries in mice overexpressing APP and suggests a pathophysiological role for the endogenous endothelin system in AD.
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Affiliation(s)
- Ahmad A Elesber
- Division of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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Girouard H, Iadecola C. Neurovascular coupling in the normal brain and in hypertension, stroke, and Alzheimer disease. J Appl Physiol (1985) 2006; 100:328-35. [PMID: 16357086 DOI: 10.1152/japplphysiol.00966.2005] [Citation(s) in RCA: 842] [Impact Index Per Article: 46.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
The brain is critically dependent on a continuous supply of blood to function. Therefore, the cerebral vasculature is endowed with neurovascular control mechanisms that assure that the blood supply of the brain is commensurate to the energy needs of its cellular constituents. The regulation of cerebral blood flow (CBF) during brain activity involves the coordinated interaction of neurons, glia, and vascular cells. Thus, whereas neurons and glia generate the signals initiating the vasodilation, endothelial cells, pericytes, and smooth muscle cells act in concert to transduce these signals into carefully orchestrated vascular changes that lead to CBF increases focused to the activated area and temporally linked to the period of activation. Neurovascular coupling is disrupted in pathological conditions, such as hypertension, Alzheimer disease, and ischemic stroke. Consequently, CBF is no longer matched to the metabolic requirements of the tissue. This cerebrovascular dysregulation is mediated in large part by the deleterious action of reactive oxygen species on cerebral blood vessels. A major source of cerebral vascular radicals in models of hypertension and Alzheimer disease is the enzyme NADPH oxidase. These findings, collectively, highlight the importance of neurovascular coupling to the health of the normal brain and suggest a therapeutic target for improving brain function in pathologies associated with cerebrovascular dysfunction.
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Affiliation(s)
- Helene Girouard
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York, USA
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Kouznetsova E, Klingner M, Sorger D, Sabri O, Grossmann U, Steinbach J, Scheunemann M, Schliebs R. Developmental and amyloid plaque‐related changes in cerebral cortical capillaries in transgenic Tg2576 Alzheimer mice. Int J Dev Neurosci 2006; 24:187-93. [PMID: 16423498 DOI: 10.1016/j.ijdevneu.2005.11.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Accepted: 11/10/2005] [Indexed: 12/25/2022] Open
Abstract
There is experimental evidence that cerebral perfusion is decreased during aging and in Alzheimer's disease. To characterize the temporal relationship between amyloid deposition, plaque size and cerebrovascular abnormalities, a semiquantitative immunohistochemical study was performed in transgenic Tg2576 mice that express the Swedish double mutation of human amyloid precursor protein (APP) and progressively develop Alzheimer-like beta-amyloid deposits. Cortical cryocut sections, obtained from mice at ages ranging between 4 and 18 months, were immunostained to label glucose transporter type 1 (GLUT1), a marker of vascular endothelial cells, and thioflavine-S to visualize plaques. Regardless of age and transgene, a laminar distribution of capillaries was observed being highest in cortical layers IV and V. The density of microvessels estimated in cortical regions with high plaque load was found to be significantly lower as compared to areas with low plaque load. Around large thioflavine-S-positive senile plaques the capillary density was low, while diffuse plaques demonstrated a close association of capillaries with no signs of any damage. The data suggest that amyloid plaque deposition differentially affects the cerebrovascular system in an age- and plaque type-related manner, and provide further evidence that beta-amyloid, in addition to its well-described neurotoxic effects, may also contribute to neuronal dysfunction through its actions on the cerebrovasculature.
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Affiliation(s)
- Elena Kouznetsova
- Paul Flechsig Institute for Brain Research, University of Leipzig, Department of Neurochemistry, Jahnallee 59, D-04109 Leipzig, Germany
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Si ML, Long C, Yang DI, Chen MF, Lee TJF. Statins prevent beta-amyloid inhibition of sympathetic alpha7-nAChR-mediated nitrergic neurogenic dilation in porcine basilar arteries. J Cereb Blood Flow Metab 2005; 25:1573-85. [PMID: 16192990 DOI: 10.1038/sj.jcbfm.9600232] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The exact mechanism underlying regional cerebral hypoperfusion in the early phase of Alzheimer's disease (AD) is not understood. We have shown in isolated porcine cerebral arteries that stimulation of sympathetic alpha7-nicotinic acetylcholine receptors (alpha7-nAChRs) causes release of nitric oxide in parasympathetic nitrergic nerves and vasodilation. We therefore examined if beta-amyloid peptides (Abetas), which play a key role in pathogenesis of AD, blocked sympathetic alpha7-nAChRs leading to reduced neurogenic nitrergic dilation in isolated porcine basilar arteries, using in vitro tissue bath, calcium image, and patch clamping techniques. The results indicated that Abeta(1-40), but not Abeta(40-1), blocked relaxation of endothelium-denuded basilar arterial rings induced by nicotine (100 micromol/L) and choline (1 mmol/L) without affecting that induced by sodium nitroprusside or isoproterenol. In cultured superior cervical ganglion (SCG) cells, Abeta(1-40), but not Abeta(40-1), blocked choline- and nicotine-induced calcium influx and inward currents. The Abeta blockade of the nitrergic vasodilation and inward currents, but not that of calcium influx, was prevented by acute pretreatment with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors mevastatin and lovastatin. These results suggest that Abeta(1-40) blocks cerebral perivascular sympathetic alpha7-nAChRs, resulting in the attenuation of cerebral nitrergic neurogenic vasodilation. This effect of Abeta may be responsible in part for cerebral hypoperfusion occurred in the early phase of the AD, which may be prevented by statins most likely because of their effects independent of cholesterol lowering. Statins may offer an alternative strategy in the prevention and treatment of AD.
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Affiliation(s)
- Min-Liang Si
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL 62794-9629, USA
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