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Nabbout M, Langham MC, Cottrell C, Wehrli FW. Quantification of neurovascular compliance with retrospectively gated phase-contrast MRI. MAGMA (NEW YORK, N.Y.) 2024; 37:307-314. [PMID: 38194215 DOI: 10.1007/s10334-023-01137-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 01/10/2024]
Abstract
OBJECTIVE Neurovascular compliance (NVC) is the change in the brain's arterial tree blood volume, ΔV, divided by the change in intra-vascular blood pressure, ΔP, during the cardiac cycle. The primary aim of this work was to evaluate the performance of MRI measurement of NVC obtained from time-resolved measurements of internal carotid artery (ICA) and vertebral artery (VA) flow rates. A secondary aim was to explore whether NVC could be estimated from common carotid (CCA) flow in conjunction with prior knowledge of mean ICA and VA fractional flow rates, given the small cross-section of ICA and VA in some populations, in particular small children. METHODS ΔV was quantified from the blood flow rate measured at the ICA and VA for actual NVC derivation. It was further estimated from individually measured CCA flow rate and mean flow fractions ICA/CCA and VA/CCA (which could alternatively be obtained from literature data), to yield estimated NVC. Time-resolved blood flow rate in CCA, ICA and VA was obtained via retrospectively-gated 2D PC-MRI at 1.5 T in healthy subjects (N = 16, 8 women, mean age 36 ± 13 years). ΔP was determined via a brachial pressure measurement. RESULTS Actual and estimated mean NVC were 27 ± 15 and 38 ± 15 μL/mmHg, respectively, and the two measurements were strongly correlated (r = 0.80; p = 0.0002) with test-retest intra-class correlation coefficients of 0.964 and 0.899. CONCLUSION Both methods yielded excellent retest precision. In spite of a large bias, actual and estimated NVC were strongly correlated.
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Affiliation(s)
- Marianne Nabbout
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Michael C Langham
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Christiana Cottrell
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Felix W Wehrli
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA.
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2
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Jin T, Li B, Li L, Qi W, Xi L. High spatiotemporal mapping of cortical blood flow velocity with an enhanced accuracy. BIOMEDICAL OPTICS EXPRESS 2024; 15:2419-2432. [PMID: 38633086 PMCID: PMC11019678 DOI: 10.1364/boe.520886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/04/2024] [Accepted: 03/04/2024] [Indexed: 04/19/2024]
Abstract
Cerebral blood flow velocity is one of the most essential parameters related to brain functions and diseases. However, most existing mapping methods suffer from either inaccuracy or lengthy sampling time. In this study, we propose a particle-size-related calibration method to improve the measurement accuracy and a random-access strategy to suppress the sampling time. Based on the proposed methods, we study the long-term progress of cortical vasculopathy and abnormal blood flow caused by glioma, short-term variations of blood flow velocity under different anesthetic depths, and cortex-wide connectivity of the rapid fluctuation of blood flow velocities during seizure onset. The experimental results demonstrate that the proposed calibration method and the random-access strategy can improve both the qualitative and quantitative performance of velocimetry techniques and are also beneficial for understanding brain functions and diseases from the perspective of cerebral blood flow.
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Affiliation(s)
- Tian Jin
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Baochen Li
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Linyang Li
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Weizhi Qi
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Lei Xi
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
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3
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Ngiam JN, Liong TS, Pramotedham T, Sia CH, Jou E, Kong WKF, Poh KK. Left ventricular vortex formation time: emerging clinical applications and limitations. Singapore Med J 2023:389617. [PMID: 38037777 DOI: 10.4103/singaporemedj.smj-2022-132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Vortex formation during left ventricular diastolic filling may provide clinically useful insights into cardiac health. In recent years, there has been growing interest in the measurement of vortex formation time (VFT), especially because it is derived noninvasively. There are important applications of VFT in valvular heart disease, athletic physiology, heart failure and hypertrophic cardiomyopathy. The formation of the vortex as fluid propagates into the left ventricle from the left atrium is important for efficient fluid transport. Quantifying VFT may thus help in evaluating and understanding disease and pathophysiological processes.
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Affiliation(s)
| | - Tze Sian Liong
- Department of Medicine, National University Health System, Singapore
| | | | - Ching-Hui Sia
- Department of Medicine; Department of Cardiology, National University Heart Centre Singapore, National University Health System, Singapore
| | - Eric Jou
- School of Clinical Medicine, University of Cambridge, Cambridge, United Kingdom
| | - William Kok-Fai Kong
- Department of Medicine; Department of Cardiology, National University Heart Centre Singapore, National University Health System, Singapore
| | - Kian-Keong Poh
- Department of Medicine; Department of Cardiology, National University Heart Centre Singapore, National University Health System, Singapore
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4
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Li Z, Chen D, Li Z, Fan H, Guo L, Sui B, Ventikos Y. A computational study of fluid transport characteristics in the brain parenchyma of dementia subtypes. J Biomech 2023; 159:111803. [PMID: 37734184 DOI: 10.1016/j.jbiomech.2023.111803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 09/15/2023] [Indexed: 09/23/2023]
Abstract
The cerebral environment is a complex system consisting of parenchymal tissue and multiple fluids. Dementia is a common class of neurodegenerative diseases, caused by structural damages and functional deficits in the cerebral environment. In order to better understand the pathology of dementia from a cerebral fluid transport angle and provide clearer evidence that could help differentiate between dementia subtypes, such as Alzheimer's disease and vascular dementia, we conducted fluid-structure interaction modelling of the brain using a multiple-network poroelasticity model, which considers both neuropathological and cerebrovascular factors. The parenchyma was further subdivided and labelled into parcellations to obtain more localised and detailed data. The numerical results were converted to computed functional images by an in-house workflow. Different cerebral blood flow (CBF) and cerebrospinal fluid (CSF) clearance abnormalities were identified in the modelling results, when comparing Alzheimer's disease and vascular dementia. This paper presents our preliminary results as a proof of concept for a novel clinical diagnostic tool, and paves the way for a larger clinical study.
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Affiliation(s)
- Zeyan Li
- Wenzhou Safety (Emergency) Institute, Tianjin University, Wenzhou, China; School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Duanduan Chen
- Wenzhou Safety (Emergency) Institute, Tianjin University, Wenzhou, China; School of Life Science, Beijing Institute of Technology, Beijing, China
| | - Zhiye Li
- Tiantan Neuroimaging Center for Excellence, China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Beijing, China
| | - Haojun Fan
- Wenzhou Safety (Emergency) Institute, Tianjin University, Wenzhou, China
| | - Liwei Guo
- Department of Mechanical Engineering, University College London, London, United Kingdom.
| | - Binbin Sui
- Tiantan Neuroimaging Center for Excellence, China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Beijing, China.
| | - Yiannis Ventikos
- Department of Mechanical Engineering, University College London, London, United Kingdom; School of Life Science, Beijing Institute of Technology, Beijing, China
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5
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Lazarev VF, Dutysheva EA, Kanunikov IE, Guzhova IV, Margulis BA. Protein Interactome of Amyloid-β as a Therapeutic Target. Pharmaceuticals (Basel) 2023; 16:312. [PMID: 37259455 PMCID: PMC9965366 DOI: 10.3390/ph16020312] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/27/2023] [Accepted: 02/08/2023] [Indexed: 04/12/2024] Open
Abstract
The amyloid concept of Alzheimer's disease (AD) assumes the β-amyloid peptide (Aβ) as the main pathogenic factor, which injures neural and other brain cells, causing their malfunction and death. Although Aβ has been documented to exert its cytotoxic effect in a solitary manner, there is much evidence to claim that its toxicity can be modulated by other proteins. The list of such Aβ co-factors or interactors includes tau, APOE, transthyretin, and others. These molecules interact with the peptide and affect the ability of Aβ to form oligomers or aggregates, modulating its toxicity. Thus, the list of potential substances able to reduce the harmful effects of the peptide should include ones that can prevent the pathogenic interactions by specifically binding Aβ and/or its partners. In the present review, we discuss the data on Aβ-based complexes in AD pathogenesis and on the compounds directly targeting Aβ or the destructors of its complexes with other polypeptides.
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Affiliation(s)
- Vladimir F. Lazarev
- Institute of Cytology of the Russian Academy of Sciences, 194064 Saint Petersburg, Russia
| | - Elizaveta A. Dutysheva
- Institute of Cytology of the Russian Academy of Sciences, 194064 Saint Petersburg, Russia
| | - Igor E. Kanunikov
- Biological Faculty, St. Petersburg State University, 199034 Saint Petersburg, Russia
| | - Irina V. Guzhova
- Institute of Cytology of the Russian Academy of Sciences, 194064 Saint Petersburg, Russia
| | - Boris A. Margulis
- Institute of Cytology of the Russian Academy of Sciences, 194064 Saint Petersburg, Russia
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Mroczkowska S, Shokr H, Benavente-Pérez A, Negi A, Bentham P, Gherghel D. Retinal Microvascular Dysfunction Occurs Early and Similarly in Mild Alzheimer's Disease and Primary-Open Angle Glaucoma Patients. J Clin Med 2022; 11:6702. [PMID: 36431179 PMCID: PMC9717733 DOI: 10.3390/jcm11226702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 11/06/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
Purpose: To assess the similarities and differences in retinal microvascular function between mild Alzheimer’s disease (AD) patients, early-stage primary open angle glaucoma (POAG) patients and healthy controls. Methods: Retinal vessel reactivity to flickering light was assessed in 10 AD, 19 POAG and 20 healthy age matched control patients by means of dynamic retinal vessel analysis (DVA, IMEDOS, GmbH, Jena, Germany) according to an established protocol. All patients additionally underwent BP measurements and blood analysis for glucose and lipid metabolism markers. Results: AD and POAG patients demonstrated comparable alterations in retinal artery reactivity, in the form of an increased arterial reaction time (RT) to flicker light on the final flicker cycle (p = 0.009), which was not replicated by healthy controls (p > 0.05). Furthermore, the sequential changes in RT on progressing from flicker one to flicker three were found to differ between healthy controls and the two disease groups (p = 0.001). Conclusion: AD and POAG patients demonstrate comparable signs of vascular dysfunction in their retinal arteries at the early stages of their disease process. This provides support for the concept of a common underlying vascular aetiology in these two neurodegenerative diseases.
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Affiliation(s)
- Stephanie Mroczkowska
- Vascular Research Laboratory, Ophthalmic Research Group, College Health and Life Sciences, Aston University, Birmingham B4 7ET, UK
- Eye and Vision Research Group, School of Health Professions, Plymouth University, Plymouth PL4 8AA, UK
| | - Hala Shokr
- Vascular Research Laboratory, Ophthalmic Research Group, College Health and Life Sciences, Aston University, Birmingham B4 7ET, UK
- Pharmacy Division, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, UK
| | - Alexandra Benavente-Pérez
- Vascular Research Laboratory, Ophthalmic Research Group, College Health and Life Sciences, Aston University, Birmingham B4 7ET, UK
| | - Anil Negi
- Medical Innovation Development and Research Unit, University Hospitals Birmingham NHS Foundation Trust, Birmingham B15 1NT, UK
| | - Peter Bentham
- Medical Innovation Development and Research Unit, University Hospitals Birmingham NHS Foundation Trust, Birmingham B15 1NT, UK
| | - Doina Gherghel
- Vascular Research Laboratory, Ophthalmic Research Group, College Health and Life Sciences, Aston University, Birmingham B4 7ET, UK
- Division of Cardiovascular Sciences, University of Manchester, Manchester M13 9PL, UK
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Cilhoroz BT, DeBlois JP, Lefferts WK, Keller AP, Pagan Lassalle P, Meyer ML, Stoner L, Heffernan KS. Exploration of cerebral hemodynamic pathways through which large artery function affects neurovascular coupling in young women. Front Cardiovasc Med 2022; 9:914439. [PMID: 36035945 PMCID: PMC9411931 DOI: 10.3389/fcvm.2022.914439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 07/25/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundThe interactions between large artery function and neurovascular coupling (NVC) are emerging as important contributors to cognitive health. Women are disproportionally affected by Alzheimer's disease and related dementia later in life. Understanding large artery correlates of NVC in young women may help with preservation of cognitive health with advancing age.PurposeTo explore the association between large artery function, NVC and cognitive performance in young women.MethodsVascular measurements were made in 61 women (21 ± 4 yrs) at rest and during a cognitive challenge (Stroop task). Transcranial Doppler was used to measure left middle cerebral artery (MCA) maximum velocity (Vmax), mean velocity (Vmean), and pulsatility index (PI). NVC was determined as MCA blood velocity reactivity to the Stroop task. Large artery function was determined using carotid-femoral pulse wave velocity (cfPWV) as a proxy measure of aortic stiffness and carotid ultrasound-derived measures of compliance and reactivity (diameter change to the Stroop task). Cognitive function was assessed separately using a computerized neurocognitive battery that included appraisal of response speed, executive function, information processing efficiency, memory, attention/concentration, and impulsivity.ResultsMCA Vmax reactivity was positively associated with executive function (β = 0.26, 95% CI 0.01–0.10); MCA Vmean reactivity was negatively associated with response speed (β = −0.33, 95% CI −0.19 to −0.02) and positively with memory score (β = 0.28, 95% CI 0.01–0.19). MCA PI reactivity was negatively associated with attention performance (β = −0.29, 95% CI −14.9 to −1.0). Path analyses identified significant paths (p < 0.05) between carotid compliance and carotid diameter reactivity to select domains of cognitive function through MCA reactivity.ConclusionsNVC was associated with cognitive function in young women. Carotid artery function assessed as carotid compliance and carotid reactivity may contribute to optimal NVC in young women through increased blood flow delivery and reduced blood flow pulsatility.
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Affiliation(s)
- Burak T. Cilhoroz
- Department of Exercise Science, Syracuse University, Syracuse, NY, United States
| | - Jacob P. DeBlois
- Department of Exercise Science, Syracuse University, Syracuse, NY, United States
| | - Wesley K. Lefferts
- Department of Kinesiology, Iowa State University, Ames, IA, United States
| | - Allison P. Keller
- Department of Exercise Science, Syracuse University, Syracuse, NY, United States
| | - Patricia Pagan Lassalle
- Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC, United States
| | - Michelle L. Meyer
- Department of Epidemiology, Gilling's School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Department of Emergency Medicine, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Lee Stoner
- Department of Exercise and Sport Science, University of North Carolina, Chapel Hill, NC, United States
- Department of Epidemiology, Gilling's School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Kevin S. Heffernan
- Department of Exercise Science, Syracuse University, Syracuse, NY, United States
- *Correspondence: Kevin S. Heffernan
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8
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Estfanous S, Daily KP, Eltobgy M, Deems NP, Anne MNK, Krause K, Badr A, Hamilton K, Carafice C, Hegazi A, Abu Khweek A, Kelani H, Nimjee S, Awad H, Zhang X, Cormet-Boyaka E, Haffez H, Soror S, Mikhail A, Nuovo G, Barrientos RM, Gavrilin MA, Amer AO. Elevated Expression of MiR-17 in Microglia of Alzheimer's Disease Patients Abrogates Autophagy-Mediated Amyloid-β Degradation. Front Immunol 2021; 12:705581. [PMID: 34426734 PMCID: PMC8379081 DOI: 10.3389/fimmu.2021.705581] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 06/30/2021] [Indexed: 01/18/2023] Open
Abstract
Autophagy is a proposed route of amyloid-β (Aβ) clearance by microglia that is halted in Alzheimer’s Disease (AD), though mechanisms underlying this dysfunction remain elusive. Here, primary microglia from adult AD (5xFAD) mice were utilized to demonstrate that 5xFAD microglia fail to degrade Aβ and express low levels of autophagy cargo receptor NBR1. In 5xFAD mouse brains, we show for the first time that AD microglia express elevated levels of microRNA cluster Mirc1/Mir17-92a, which is known to downregulate autophagy proteins. By in situ hybridization in post-mortem AD human tissue sections, we observed that the Mirc1/Mir17-92a cluster member miR-17 is also elevated in human AD microglia, specifically in the vicinity of Aβ deposits, compared to non-disease controls. We show that NBR1 expression is negatively correlated with expression of miR-17 in human AD microglia via immunohistopathologic staining in human AD brain tissue sections. We demonstrate in healthy microglia that autophagy cargo receptor NBR1 is required for Aβ degradation. Inhibiting elevated miR-17 in 5xFAD mouse microglia improves Aβ degradation, autophagy, and NBR1 puncta formation in vitro and improves NBR1 expression in vivo. These findings offer a mechanism behind dysfunctional autophagy in AD microglia which may be useful for therapeutic interventions aiming to improve autophagy function in AD.
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Affiliation(s)
- Shady Estfanous
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States.,Biochemistry and Molecular Biology Department, Faculty of Pharmacy, Helwan University, Cairo, Egypt
| | - Kylene P Daily
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States
| | - Mostafa Eltobgy
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States
| | - Nicholas P Deems
- Institute for Behavioral Medicine Research, Ohio State University, Columbus, OH, United States
| | - Midhun N K Anne
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States
| | - Kathrin Krause
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States.,Max Planck Unit for the Science of Pathogens, Berlin, Germany
| | - Asmaa Badr
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States
| | - Kaitlin Hamilton
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States
| | - Cierra Carafice
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States
| | - Ahmad Hegazi
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States
| | - Arwa Abu Khweek
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States.,Department of Biology and Biochemistry, Birzeit University, West Bank, Palestine
| | - Hesham Kelani
- Department of Anesthesiology, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Shahid Nimjee
- Department of Neurological Surgery, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Hamdy Awad
- Department of Anesthesiology, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Xiaoli Zhang
- Center for Biostatistics, Ohio State University, Columbus, OH, United States
| | - Estelle Cormet-Boyaka
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, United States
| | - Hesham Haffez
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy, Helwan University, Cairo, Egypt.,Center of Excellence, Helwan Structure Biology Research, Cairo, Egypt
| | - Sameh Soror
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy, Helwan University, Cairo, Egypt.,Center of Excellence, Helwan Structure Biology Research, Cairo, Egypt
| | - Adel Mikhail
- GNOME DIAGNOSTICS, Department of Scientific Research, Powell, OH, United States
| | - Gerard Nuovo
- GNOME DIAGNOSTICS, Department of Scientific Research, Powell, OH, United States
| | - Ruth M Barrientos
- Institute for Behavioral Medicine Research, Ohio State University, Columbus, OH, United States
| | - Mikhail A Gavrilin
- Department of Internal Medicine, Ohio State University, Columbus, OH, United States
| | - Amal O Amer
- Department of Microbial Infection and Immunity, Infectious Diseases Institute, The Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States
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Chintamaneni PK, Krishnamurthy PT, Pindiprolu SKSS. Polysorbate-80 surface modified nano-stearylamine BQCA conjugate for the management of Alzheimer's disease. RSC Adv 2021; 11:5325-5334. [PMID: 35423107 PMCID: PMC8694636 DOI: 10.1039/d1ra00049g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 01/13/2021] [Indexed: 01/31/2023] Open
Abstract
Acetylcholinesterase (AChE) inhibitors such as donepezil, galantamine and rivastigmine are used for the management of dementia in Alzheimer's Disease (AD). These drugs elevate endogenous acetylcholine (ACh) levels at the M1 muscarinic receptor in the brain to achieve therapeutic benefits. However, their side effects, such as nausea, vomiting, dizziness, insomnia, loss of appetite, altered heart rate, etc., are related to non-specific peripheral activation of M2-M5 muscarinic subtypes. It is logical, therefore, to develop drugs that selectively activate brain M1 receptors. Unfortunately, the orthosteric site homology among the receptor subtypes does not permit this approach. An alternative approach is to use positive allosteric modulator (PAM) of M1 receptors like benzyl quinolone carboxylic acid (BQCA). PAMs although devoid of M1 agonist activity, however, when bound, enhance the binding affinity of orthosteric ligand, Ach. The current challenge with PAMS is their low brain half-life, permeability, and higher elimination rates. This study reports active targeting of brain M1 receptors using surface modified nano lipid-drug conjugates (LDC) of M1 PAM, BQCA, to treat AD. Polysorbate-80 (P-80) surface modified stearylamine (SA)-BQCA conjugated nanoparticles (BQCA-SA-P80-NPs) were prepared by conjugating BQCA to SA, followed by the formation of nanoparticles (NPs) using P-80 by solvent injection method. The BQCA-SA-P80-NPs are near-spherical with a particle size (PS) of 166.62 ± 1.24 nm and zeta potential (ZP) of 23.59 ± 0.37 mV. In the in vitro cytotoxicity (SH-SY5Y cells) and hemolysis assays, BQCA-SA-P80-NPs, show acceptable safety and compatibility. In mice, Alzheimer's model, BQCA-SA-P80-NPs significantly prevent STZ induced changes in memory, neuronal Aβ1-42, p-Tau, APP, NF-κB, and BACE levels and neuronal cell death, when compared to untreated disease control and naïve BQCA treated group. Further, BQCA-SA-P80-NPs significantly improve the therapeutic efficacy of AChE inhibitor, donepezil (DPZ), indicating its potentiating effects. In vivo biodistribution studies in mice show selective accumulation of BQCA-SA-P80-NPs in the brain, suggesting an improved brain bioavailability and reduced peripheral side effects of BQCA. The study results demonstrate that BQCA-SA-P80-NPs can improve brain bioavailability and therapeutic efficacy of BQCA in AD.
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Affiliation(s)
- Pavan Kumar Chintamaneni
- Department of Pharmacology, JSS College of Pharmacy (JSS Academy of Higher Education & Research) Ooty, The Nilgiris Tamil Nadu-643001 India +91-7598223850
- Department of Pharmaceutics, Raghavendra Institute of Pharmaceutical Education and Research (RIPER) Anantapuramu 51572 Andhra Pradesh India
| | - Praveen Thaggikuppe Krishnamurthy
- Department of Pharmacology, JSS College of Pharmacy (JSS Academy of Higher Education & Research) Ooty, The Nilgiris Tamil Nadu-643001 India +91-7598223850
| | - Sai Kiran S S Pindiprolu
- Department of Pharmacology, JSS College of Pharmacy (JSS Academy of Higher Education & Research) Ooty, The Nilgiris Tamil Nadu-643001 India +91-7598223850
- Department of Pharmacology, Aditya Pharmacy College Surampalem East Godavari 533 437 Andhra Pradesh India
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10
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Maliszewska-Cyna E, Vecchio LM, Thomason LAM, Oore JJ, Steinman J, Joo IL, Dorr A, McLaurin J, Sled JG, Stefanovic B, Aubert I. The effects of voluntary running on cerebrovascular morphology and spatial short-term memory in a mouse model of amyloidosis. Neuroimage 2020; 222:117269. [PMID: 32818618 DOI: 10.1016/j.neuroimage.2020.117269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/06/2020] [Accepted: 08/10/2020] [Indexed: 12/27/2022] Open
Abstract
Physical activity has been correlated with a reduced risk of cognitive decline, including that associated with vascular dementia, mild cognitive impairment (MCI) and Alzheimer's disease (AD); recent literature suggests this may in part result from benefits to the cerebrovascular network. Using a transgenic (Tg) mouse model of AD, we evaluated the effect of running on cortical and hippocampal vascular morphology, cerebral amyloid angiopathy, amyloid plaque load, and spatial memory. TgCRND8 mice present with progressive amyloid pathology, advancing from the cortex to the hippocampus in a time-dependent manner. We postulated that the characteristic progression of pathology could lead to differential, time-dependent effects of physical activity on vascular morphology in these brain regions at 6 months of age. We used two-photon fluorescent microscopy and 3D vessel tracking to characterize vascular and amyloid pathology in sedentary TgCRND8 mice compared those who have a history of physical activity (unlimited access to a running wheel, from 3 to 6 months of age). In sedentary TgCRND8 mice, capillary density was found to be lower in the cortex and higher in the hippocampus compared to non-transgenic (nonTg) littermates. Capillary length, vessel branching, and non-capillary vessel tortuosity were also higher in the hippocampus of sedentary TgCRND8 compared to nonTg mice. Three months of voluntary running resulted in normalizing cortical and hippocampal microvascular morphology, with no significant difference between TgCRND8 and nonTg mice. The benefits of physical activity on cortical and hippocampal vasculature in 6-month old TgCRND8 mice were not paralleled by significant changes on parenchymal and cerebral amyloid pathology. Short-term spatial memory- as evaluated by performance in the Y-maze- was significantly improved in running compared to sedentary TgCRND8 mice. These results suggest that long-term voluntary running contributes to the maintenance of vascular morphology and spatial memory in TgCRND8 mice, even in the absence of an effect on amyloid pathology.
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Affiliation(s)
- Ewelina Maliszewska-Cyna
- Hurvitz Brain Sciences, Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Ave, S112, Toronto, Ontario M4N 3M5, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Laura M Vecchio
- Hurvitz Brain Sciences, Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Ave, S112, Toronto, Ontario M4N 3M5, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.
| | - Lynsie A M Thomason
- Hurvitz Brain Sciences, Physical Sciences, Sunnybrook Research Institute, Canada
| | - Jonathan J Oore
- Hurvitz Brain Sciences, Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Ave, S112, Toronto, Ontario M4N 3M5, Canada
| | - Joe Steinman
- Mouse Imaging Centre, Hospital for Sick Children, Canada; Department of Medical Biophysics, University of Toronto, Canada
| | - Illsung Lewis Joo
- Hurvitz Brain Sciences, Physical Sciences, Sunnybrook Research Institute, Canada
| | - Adrienne Dorr
- Hurvitz Brain Sciences, Physical Sciences, Sunnybrook Research Institute, Canada
| | - JoAnne McLaurin
- Hurvitz Brain Sciences, Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Ave, S112, Toronto, Ontario M4N 3M5, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - John G Sled
- Mouse Imaging Centre, Hospital for Sick Children, Canada; Department of Medical Biophysics, University of Toronto, Canada
| | - Bojana Stefanovic
- Hurvitz Brain Sciences, Physical Sciences, Sunnybrook Research Institute, Canada; Department of Medical Biophysics, University of Toronto, Canada
| | - Isabelle Aubert
- Hurvitz Brain Sciences, Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Ave, S112, Toronto, Ontario M4N 3M5, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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11
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Susceptibility-weighted imaging and transcranial Doppler ultrasound in patients with cerebral small vessel disease. Neurol Sci 2020; 41:2853-2858. [DOI: 10.1007/s10072-020-04414-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/13/2020] [Indexed: 10/24/2022]
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12
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Holmgren M, Wåhlin A, Dunås T, Malm J, Eklund A. Assessment of Cerebral Blood Flow Pulsatility and Cerebral Arterial Compliance With 4D Flow MRI. J Magn Reson Imaging 2019; 51:1516-1525. [PMID: 31713964 PMCID: PMC7216927 DOI: 10.1002/jmri.26978] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/08/2019] [Accepted: 10/08/2019] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Four-dimensional flow magnetic resonance imaging (4D flow MRI) enables efficient investigation of cerebral blood flow pulsatility in the cerebral arteries. This is important for exploring hemodynamic mechanisms behind vascular diseases associated with arterial pulsations. PURPOSE To investigate the feasibility of pulsatility assessments with 4D flow MRI, its agreement with reference two-dimensional phase-contrast MRI (2D PC-MRI) measurements, and to demonstrate how 4D flow MRI can be used to assess cerebral arterial compliance and cerebrovascular resistance in major cerebral arteries. STUDY TYPE Prospective. SUBJECTS Thirty-five subjects (20 women, 79 ± 5 years, range 70-91 years). FIELD STRENGTH/SEQUENCE 4D flow MRI (PC-VIPR) and 2D PC-MRI acquired with a 3T scanner. ASSESSMENT Time-resolved flow was assessed in nine cerebral arteries. From the pulsatile flow waveform in each artery, amplitude (ΔQ), volume load (ΔV), and pulsatility index (PI) were calculated. To reduce high-frequency noise in the 4D flow MRI data, the flow waveforms were low-pass filtered. From the total cerebral blood flow, total PI (PItot ), total volume load (ΔVtot ), cerebral arterial compliance (C), and cerebrovascular resistance (R) were calculated. STATISTICAL TESTS Two-tailed paired t-test, intraclass correlation (ICC). RESULTS There was no difference in ΔQ between 4D flow MRI and the reference (0.00 ± 0.022 ml/s, mean ± SEM, P = 0.97, ICC = 0.95, n = 310) with a cutoff frequency of 1.9 Hz and 15 cut plane long arterial segments. For ΔV, the difference was -0.006 ± 0.003 ml (mean ± SEM, P = 0.07, ICC = 0.93, n = 310) without filtering. Total R was 11.4 ± 2.41 mmHg/(ml/s) (mean ± SD) and C was 0.021 ± 0.009 ml/mmHg (mean ± SD). ΔVtot was 1.21 ± 0.29 ml (mean ± SD) with an ICC of 0.82 compared with the reference. PItot was 1.08 ± 0.21 (mean ± SD). DATA CONCLUSION We successfully assessed 4D flow MRI cerebral arterial pulsatility, cerebral arterial compliance, and cerebrovascular resistance. Averaging of multiple cut planes and low-pass filtering was necessary to assess accurate peak-to-peak features in the flow rate waveforms. LEVEL OF EVIDENCE 2 Technical Efficacy Stage: 2 J. Magn. Reson. Imaging 2020;51:1516-1525.
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Affiliation(s)
| | - Anders Wåhlin
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.,Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
| | - Tora Dunås
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.,Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden.,Center for Demographic and Aging Research, Umeå University, Umeå, Sweden
| | - Jan Malm
- Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden.,Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
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13
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Silva GM, Barcelos MP, Poiani JGC, Hage-Melim LIDS, da Silva CHTDP. Allosteric Modulators of Potential Targets Related to Alzheimer's Disease: a Review. ChemMedChem 2019; 14:1467-1483. [PMID: 31310701 DOI: 10.1002/cmdc.201900299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/05/2019] [Indexed: 12/15/2022]
Abstract
Among neurodegenerative disorders, Alzheimer's disease (AD) is the most common type of dementia, and there is an urgent need to discover new and efficacious forms of treatment for it. Pathological patterns of AD include cholinergic dysfunction, increased β-amyloid (Aβ) peptide concentration, the appearance of neurofibrillary tangles, among others, all of which are strongly associated with specific biological targets. Interactions observed between these targets and potential drug candidates in AD most often occur by competitive mechanisms driven by orthosteric ligands that sometimes result in the production of side effects. In this context, the allosteric mechanism represents a key strategy; this can be regarded as the selective modulation of such targets by allosteric modulators in an advantageous manner, as this may decrease the likelihood of side effects. The purpose of this review is to present an overview of compounds that act as allosteric modulators of the main biological targets related to AD.
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Affiliation(s)
- Guilherme Martins Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-903, Ribeirão Preto, Brazil.,Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14090-901, Ribeirão Preto, Brazil
| | - Mariana Pegrucci Barcelos
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-903, Ribeirão Preto, Brazil.,Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14090-901, Ribeirão Preto, Brazil
| | - João Gabriel Curtolo Poiani
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-903, Ribeirão Preto, Brazil
| | - Lorane Izabel da Silva Hage-Melim
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-903, Ribeirão Preto, Brazil.,Departamento de Ciências Biológicas e da Saúde, Curso de Farmácia, Universidade Federal do Amapá, Rod. Juscelino Kubitschek, KM-02, 68903-419, Macapá, Brazil
| | - Carlos Henrique Tomich de Paula da Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-903, Ribeirão Preto, Brazil.,Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14090-901, Ribeirão Preto, Brazil
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14
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Li HC, Chen PY, Cheng HF, Kuo YM, Huang CC. In Vivo Visualization of Brain Vasculature in Alzheimer's Disease Mice by High-Frequency Micro-Doppler Imaging. IEEE Trans Biomed Eng 2019; 66:3393-3401. [PMID: 30872220 DOI: 10.1109/tbme.2019.2904702] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Cerebrovascular disorders are associated with Alzheimer's disease (AD). Functional analysis of the cerebral vasculature requires an in vivo approach to visualize the blood flow in small animal brains. This paper proposes a high-frequency micro-Doppler imaging (HFμDI) technology for mapping mouse cerebral vasculature. METHODS HFμDI used a 40-MHz transducer with an ultrafast ultrasound imaging technology that enabled in vivo visualization of the mouse brain up to 3 mm in depth; furthermore, a minimal vessel diameter of 48 μm could be determined. RESULTS Animal experiments determined that the cortical and hippocampal vessel density in young wild-type (WT) mice was similar to that in middle-aged WT mice. However, compared with the vessel density in middle-aged WT mice, that in middle-aged mice with AD was significantly lower, particularly in the hippocampus. DISCUSSION In vivo observation of cerebral vasculature demonstrated the effectiveness of HFμDI for the preclinical study of AD, and a potential way for human diagnosis was provided.
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15
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Jin WS, Bu XL, Wang YR, Li L, Li WW, Liu YH, Zhu C, Yao XQ, Chen Y, Gao CY, Zhang T, Zhou HD, Zeng F, Wang YJ. Reduced Cardiovascular Functions in Patients with Alzheimer’s Disease. J Alzheimers Dis 2017; 58:919-925. [DOI: 10.3233/jad-170088] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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16
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Voss HU, Dyke JP, Tabelow K, Schiff ND, Ballon DJ. Magnetic resonance advection imaging of cerebrovascular pulse dynamics. J Cereb Blood Flow Metab 2017; 37:1223-1235. [PMID: 27221244 PMCID: PMC5453446 DOI: 10.1177/0271678x16651449] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We analyze the pulsatile signal component of dynamic echo planar imaging data from the brain by modeling the dependence between local temporal and spatial signal variability. The resulting magnetic resonance advection imaging maps depict the location of major arteries. Color direction maps allow for visualization of the direction of blood vessels. The potential significance of magnetic resonance advection imaging maps is demonstrated on a functional magnetic resonance imaging data set of 19 healthy subjects. A comparison with the here introduced pulse coherence maps, in which the echo planar imaging signal is correlated with a cardiac pulse signal, shows that the magnetic resonance advection imaging approach results in a better spatial definition without the need for a pulse reference. In addition, it is shown that magnetic resonance advection imaging velocities can be estimates of pulse wave velocities if certain requirements are met, which are specified. Although for this application magnetic resonance advection imaging velocities are not quantitative estimates of pulse wave velocities, they clearly depict local pulsatile dynamics. Magnetic resonance advection imaging can be applied to existing dynamic echo planar imaging data sets with sufficient spatiotemporal resolution. It is discussed whether magnetic resonance advection imaging might have the potential to evolve into a biomarker for the health of the cerebrovascular system.
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Affiliation(s)
- Henning U Voss
- 1 Department of Radiology, Citigroup Biomedical Imaging Center, Weill Cornell Medicine, New York, NY, USA
| | - Jonathan P Dyke
- 1 Department of Radiology, Citigroup Biomedical Imaging Center, Weill Cornell Medicine, New York, NY, USA
| | - Karsten Tabelow
- 2 Weierstrass Institute for Applied Analysis and Stochastics, Berlin, Germany
| | - Nicholas D Schiff
- 3 Department of Neurology and Neuroscience, Weill Cornell Medicine, New York, NY, USA
| | - Douglas J Ballon
- 1 Department of Radiology, Citigroup Biomedical Imaging Center, Weill Cornell Medicine, New York, NY, USA
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17
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Bateman GA, Lechner-Scott J, Lea RA. A comparison between the pathophysiology of multiple sclerosis and normal pressure hydrocephalus: is pulse wave encephalopathy a component of MS? Fluids Barriers CNS 2016; 13:18. [PMID: 27658732 PMCID: PMC5034419 DOI: 10.1186/s12987-016-0041-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 09/08/2016] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND It has been suggested there is a chronic neurodegenerative disorder, underlying the pathophysiology of multiple sclerosis (MS), which is distinct from the more obvious immune-mediated attack on the white matter. Limited data exists indicating there is an alteration in pulse wave propagation within the craniospinal cavity in MS, similar to the findings in normal pressure hydrocephalus (NPH). It is hypothesized MS may harbor pulse wave encephalopathy. The purpose of this study is to compare blood flow and pulse wave measurements in MS patients with a cohort of NPH patients and control subjects, to test this hypothesis. METHODS Twenty patients with MS underwent magnetic resonance (MR) flow quantification techniques. Mean blood flow and stroke volume were measured in the arterial inflow and venous out flow from the sagittal (SSS) and straight sinus (ST). The arteriovenous delay (AVD) was defined. The results were compared with both age-matched controls and NPH patients. RESULTS In MS there was a 35 % reduction in arteriovenous delay and a 5 % reduction in the percentage of the arterial inflow returning via the sagittal sinus compared to age matched controls. There was an alteration in pulse wave propagation, with a 26 % increase in arterial stroke volume but 30 % reduction in SSS and ST stroke volume. The AVD and blood flow changes were in the same direction to those of NPH patients. CONCLUSIONS There are blood flow and pulsation propagation changes in MS patients which are similar to those of NPH patients. The findings would be consistent with an underlying pulse wave encephalopathy component in MS.
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Affiliation(s)
- Grant A. Bateman
- Department of Medical Imaging, John Hunter Hospital, Locked Bag 1, Newcastle Region Mail Center, Newcastle, 2310 Australia
- Newcastle University Faculty of Health, Callaghan Campus Newcastle, Newcastle, Australia
| | - Jeannette Lechner-Scott
- Newcastle University Faculty of Health, Callaghan Campus Newcastle, Newcastle, Australia
- Department of Neurology, John Hunter Hospital, Newcastle, Australia
- Hunter Medical Research Institute, Newcastle, Australia
| | - Rodney A. Lea
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
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18
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Abstract
In the nineteenth century, prior to the introduction of the cuff sphygmomanometer, arteriosclerosis (stiffening of arteries) was recognized by clinicians and by life insurance companies as an indicator of vascular aging and cardiovascular risk, even in asymptomatic individuals. Through the twentieth century, views on aging came to focus on values of systolic and diastolic pressure and on obstructive atherosclerotic disease. Such focus deflected attention from the primary aging change which occurs in all societies, and is represented by stiffening and dilation of the proximal aorta. This review emphasizes the cushioning function of elastic arteries — principally the aorta — and how in youth this results in optimal interaction with the heart, and optimal steady flow through peripheral resistance vessels. Aortic stiffening with age is principally due to fatigue and fracture of elastin lamellae, with transfer of stress to stiffer collagenous components. Stiffening increases left ventricular load and myocardial blood requirement, but limits the capacity for blood supply during diastole. Consequences are cardiac failure and predisposition to ischaemia. The second, under-appreciated effect of aortic stiffening is transmission of flow pulsations downstream into vasodilated organs, principally brain and kidney, where pulsatile energy is dissipated and fragile microvessels are damaged. This accounts for micro infarcts and microhaemorrhages, with specialized cell damage, cognitive decline and renal failure. The aging process can be best monitored by change in the arterial pressure wave rather than by reliance on the cuff sphygmomanometer. This reintroduces the approaches by clinicians and life insurance examiners of the nineteenth century, endorses modern treatments for established disease, and holds the promise of detecting premature arterial degeneration, and better applying lifestyle measures and vasoactive medications to modify the aging process.
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Affiliation(s)
- Michael F. O'Rourke
- Suite 810, St Vincent's Clinic, 438 Victoria Street, Darlinghurst, NSW 2010, Australia,
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19
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Bien-Ly N, Boswell CA, Jeet S, Beach TG, Hoyte K, Luk W, Shihadeh V, Ulufatu S, Foreman O, Lu Y, DeVoss J, van der Brug M, Watts RJ. Lack of Widespread BBB Disruption in Alzheimer's Disease Models: Focus on Therapeutic Antibodies. Neuron 2016; 88:289-97. [PMID: 26494278 DOI: 10.1016/j.neuron.2015.09.036] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 09/08/2015] [Accepted: 09/17/2015] [Indexed: 12/21/2022]
Abstract
The blood-brain barrier (BBB) limits brain uptake of therapeutic antibodies. It is believed that the BBB is disrupted in Alzheimer's disease (AD), potentially increasing drug permeability de facto. Here we compared active versus passive brain uptake of systemically dosed antibodies (anti-transferrin receptor [TfR] bispecific versus control antibody) in mouse models of AD. We first confirmed BBB disruption in a mouse model of multiple sclerosis as a positive control. Importantly, we found that BBB permeability was vastly spared in mouse models of AD, including PS2-APP, Tau transgenics, and APOE4 knockin mice. Brain levels of TfR in mouse models or in human cases of AD resembled controls, suggesting target engagement of TfR bispecific is not limited. Furthermore, infarcts from human AD brain showed similar occurrences compared to age-matched controls. These results question the widely held view that the BBB is largely disrupted in AD, raising concern about assumptions of drug permeability in disease.
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Affiliation(s)
- Nga Bien-Ly
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA.
| | - C Andrew Boswell
- Department of Development Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Surinder Jeet
- Department of Translational Immunology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Thomas G Beach
- Banner Sun Health Research Institutes, 10515 West Santa Fe Drive, Sun City, AZ 85372, USA
| | - Kwame Hoyte
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Wilman Luk
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Vera Shihadeh
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Sheila Ulufatu
- Department of Development Sciences, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Oded Foreman
- Department of Pathology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Yanmei Lu
- Department of Biochemical and Cellular Pharmacology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Jason DeVoss
- Department of Translational Immunology, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
| | - Marcel van der Brug
- Department of Diagnostic Discovery, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA.
| | - Ryan J Watts
- Department of Neuroscience, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA
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20
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Truran S, Weissig V, Madine J, Davies HA, Guzman-Villanueva D, Franco DA, Karamanova N, Burciu C, Serrano G, Beach TG, Migrino RQ. Nanoliposomes protect against human arteriole endothelial dysfunction induced by β-amyloid peptide. J Cereb Blood Flow Metab 2016; 36:405-12. [PMID: 26661197 PMCID: PMC4759678 DOI: 10.1177/0271678x15610134] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 09/02/2015] [Indexed: 12/13/2022]
Abstract
We tested whether nanoliposomes containing phosphatidylcholine, cholesterol and phosphatidic acid (NLPA) prevent β-amyloid 1-42 (Aβ42) fibrillation and Aβ42-induced human arteriole endothelial dysfunction. NLPA abolished Aβ42 fibril formation (thioflavin-T fluorescence/electron microscopy). In ex-vivo human adipose and leptomeningeal arterioles, Aβ42 impaired dilator response to acetylcholine that was reversed by NLPA; this protection was abolished by L-NG-nitroarginine methyl ester. Aβ42 reduced human umbilical vein endothelial cell NO production that was restored by NLPA. Nanoliposomes prevented Aβ42 amyloid formation, reversed Aβ42-induced human microvascular endothelial dysfunction and may be useful in Alzheimer's disease.
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Affiliation(s)
- Seth Truran
- Phoenix Veterans Affair Health Care System, Phoenix, AZ, USA
| | | | | | | | | | - Daniel A Franco
- Phoenix Veterans Affair Health Care System, Phoenix, AZ, USA
| | - Nina Karamanova
- Phoenix Veterans Affair Health Care System, Phoenix, AZ, USA
| | - Camelia Burciu
- Phoenix Veterans Affair Health Care System, Phoenix, AZ, USA
| | - Geidy Serrano
- Banner Sun Health Research Institute, Sun City, AZ, USA
| | | | - Raymond Q Migrino
- Phoenix Veterans Affair Health Care System, Phoenix, AZ, USA University of Arizona College of Medicine, Phoenix, AZ, USA
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21
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Pulse wave myelopathy: An update of an hypothesis highlighting the similarities between syringomyelia and normal pressure hydrocephalus. Med Hypotheses 2015; 85:958-61. [PMID: 26362731 DOI: 10.1016/j.mehy.2015.08.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 08/26/2015] [Indexed: 10/23/2022]
Abstract
Most hypotheses trying to explain the pathophysiology of idiopathic syringomyelia involve mechanisms whereby CSF is pumped against a pressure gradient, from the subarachnoid space into the cord parenchyma. On review, these theories have universally failed to explain the disease process. A few papers have suggested that the syrinx fluid may originate from the cord capillary bed itself. However, in these papers, the fluid is said to accumulate due to impaired fluid drainage out of the cord. Again, there is little evidence to substantiate this. This proffered hypothesis looks at the problem from the perspective that syringomyelia and normal pressure hydrocephalus are almost identical in their manifestations but only differ in their site of effect within the neuraxis. It is suggested that the primary trigger for syringomyelia is a reduction in the compliance of the veins draining the spinal cord. This reduces the efficiency of the pulse wave dampening, occurring within the cord parenchyma, increasing arteriolar and capillary pulse pressure. The increased capillary pulse pressure opens the blood-spinal cord barrier due to a direct effect upon the wall integrity and interstitial fluid accumulates due to an increased secretion rate. An increase in arteriolar pulse pressure increases the kinetic energy within the cord parenchyma and this disrupts the cytoarchitecture allowing the fluid to accumulate into small cystic regions in the cord. With time the cystic regions coalesce to form one large cavity which continues to increase in size due to the ongoing interstitial fluid secretion and the hyperdynamic cord vasculature.
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22
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Endothelial Dysfunction and Amyloid-β-Induced Neurovascular Alterations. Cell Mol Neurobiol 2015; 36:155-65. [PMID: 26328781 DOI: 10.1007/s10571-015-0256-9] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/20/2015] [Indexed: 01/08/2023]
Abstract
Alzheimer's disease (AD) and cerebrovascular diseases share common vascular risk factors that have disastrous effects on cerebrovascular regulation. Endothelial cells, lining inner walls of cerebral blood vessels, form a dynamic interface between the blood and the brain and are critical for the maintenance of neurovascular homeostasis. Accordingly, injury in endothelial cells is regarded as one of the earliest symptoms of impaired vasoregulatory mechanisms. Extracellular buildup of amyloid-β (Aβ) is a central pathogenic factor in AD. Aβ exerts potent detrimental effects on cerebral blood vessels and impairs endothelial structure and function. Recent evidence implicates vascular oxidative stress and activation of the non-selective cationic channel transient receptor potential melastatin (TRPM)-2 on endothelial cells in the mechanisms of Aβ-induced neurovascular dysfunction. Thus, Aβ triggers opening of TRPM2 channels in endothelial cells leading to intracellular Ca(2+) overload and vasomotor dysfunction. The cerebrovascular dysfunction may contribute to AD pathogenesis by reducing the cerebral blood supply, leading to increased susceptibility to vascular insufficiency, and by promoting Aβ accumulation. The recent realization that vascular factors contribute to AD pathobiology suggests new targets for the prevention and treatment of this devastating disease.
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23
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Kim SA, Park JB, O'Rourke MF. Vasculopathy of Aging and the Revised Cardiovascular Continuum. Pulse (Basel) 2015; 3:141-7. [PMID: 26587463 DOI: 10.1159/000435901] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
There have been attempts to explain the process of developments in overt cardiovascular disease, resulting in the presentation of the classic cardiovascular disease continuum and the aging cardiovascular continuum. Although the starting points of these two continua are different, they meet in the midstream of the cycle and reach a consensus at the end of the process. The announcement of the aging cardiovascular continuum made both continua complete, explaining the cardiovascular events in patients without atherosclerotic cardiovascular disease with aging. Impairment of the vascular structure by pulse wave and reflected wave is considered the cause of aortic damage, which influences the development of ischemic heart disease and the development of overt renal disease or cerebrovascular disease. The pathophysiology of vascular aging through pulse wave and its effect on other organs was discussed with Prof. Michael F. O'Rourke who devised the aging cardiovascular continuum.
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Affiliation(s)
- Su-A Kim
- Division of Cardiology, Department of Medicine, Cheil General Hospital, Dankook University, College of Medicine, Seoul, Republic of Korea
| | - Jeong Bae Park
- Division of Cardiology, Department of Medicine, Cheil General Hospital, Dankook University, College of Medicine, Seoul, Republic of Korea
| | - Michael F O'Rourke
- Victor Chang Cardiac Research Institute, St. Vincent's Clinic, University of New South Wales, Sydney, N.S.W., Australia
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24
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Katsimpardi L, Rubin LL. Young systemic factors as a medicine for age-related neurodegenerative diseases. NEUROGENESIS 2015; 2:e1004971. [PMID: 27502604 PMCID: PMC4973601 DOI: 10.1080/23262133.2015.1004971] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 12/14/2014] [Accepted: 01/03/2015] [Indexed: 01/19/2023]
Abstract
It is widely known that neurogenesis, brain function and cognition decline with aging. Increasing evidence suggests that cerebrovascular dysfunction is a major cause of cognitive impairment in the elderly but is also involved in age-related neurodegenerative diseases. Finding ways and molecules that reverse this process and ameliorate age- and disease-related cognitive impairment by targeting vascular and neurogenic deterioration would be of great therapeutic value. In Katsimpardi et al. we reported that young blood has a dual beneficial effect in the aged brain by restoring age-related decline in neurogenesis as well as inducing a striking remodeling of the aged vasculature and restoring blood flow to youthful levels. Additionally, we identified a youthful systemic factor, GDF11 that recapitulates these beneficial effects of young blood. We believe that the identification of young systemic factors that can rejuvenate the aged brain opens new roads to therapeutic intervention for neurodegenerative diseases by targeting both neural stem cells and neurogenesis as well as at the vasculature.
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Affiliation(s)
- Lida Katsimpardi
- Department of Stem Cell and Regenerative Biology; Harvard University and Harvard Stem Cell Institute ; Cambridge, MA USA
| | - Lee L Rubin
- Department of Stem Cell and Regenerative Biology; Harvard University and Harvard Stem Cell Institute ; Cambridge, MA USA
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25
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Çalık AN, Özcan KS, Yüksel G, Güngör B, Aruğarslan E, Varlibas F, Ekmekci A, Osmonov D, Tatlısu MA, Karaca M, Bolca O, Erdinler İ. Altered diastolic function and aortic stiffness in Alzheimer's disease. Clin Interv Aging 2014; 9:1115-21. [PMID: 25075180 PMCID: PMC4107181 DOI: 10.2147/cia.s63337] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background Alzheimer’s disease (AD) is closely linked to cardiovascular risk factors. Methods Echocardiographic studies were performed, including left ventricular diastolic functions, left and right atrial conduction times, and arterial stiffness parameters, namely stiffness index, pressure-strain elastic modulus, and distensibility, on 29 patients with AD and 24 age-matched individuals with normal cognitive function. Results The peak mitral flow velocity of the early rapid filling wave (E) was lower, and the peak velocity of the late filling wave caused by atrial contraction (A), deceleration time of peak E velocity, and isovolumetric relaxation time were higher in the AD group. The early myocardial peak (Ea) velocity was significantly lower in AD patients, whereas the late diastolic (Aa) velocity and E/Ea ratio were similar between the two groups. In Alzheimer patients, stiffness index and pressure-strain elastic modulus were higher, and distensibility was significantly lower in the AD group compared to the control. Interatrial electromechanical delay was significantly longer in the AD group. Conclusion Our findings suggest that patients with AD are more likely to have diastolic dysfunction, higher atrial conduction times, and increased arterial stiffness compared to the controls of same sex and similar age.
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Affiliation(s)
- Ali Nazmi Çalık
- Department of Cardiology, Yozgat State Hospital, Yozgat, Turkey
| | - Kazım Serhan Özcan
- Department of Cardiology, Derince Training and Research Hospital, Kocaeli, Turkey
| | - Gülbün Yüksel
- Department of Neurology, Haydarpaşa Numune Training and Research Hospital, Istanbul, Turkey
| | - Barısş Güngör
- Department of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, Turkey
| | - Emre Aruğarslan
- Department of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, Turkey
| | - Figen Varlibas
- Department of Neurology, Haydarpaşa Numune Training and Research Hospital, Istanbul, Turkey
| | - Ahmet Ekmekci
- Department of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, Turkey
| | - Damirbek Osmonov
- Department of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, Turkey
| | - Mustafa Adem Tatlısu
- Department of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, Turkey
| | - Mehmet Karaca
- Department of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, Turkey
| | - Osman Bolca
- Department of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, Turkey
| | - İzzet Erdinler
- Department of Cardiology, Siyami Ersek Cardiovascular and Thoracic Surgery Center, Istanbul, Turkey
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Jiang S, Li Y, Zhang C, Zhao Y, Bu G, Xu H, Zhang YW. M1 muscarinic acetylcholine receptor in Alzheimer's disease. Neurosci Bull 2014; 30:295-307. [PMID: 24590577 DOI: 10.1007/s12264-013-1406-z] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 10/28/2013] [Indexed: 01/31/2023] Open
Abstract
The degeneration of cholinergic neurons and cholinergic hypofunction are pathologies associated with Alzheimer's disease (AD). Muscarinic acetylcholine receptors (mAChRs) mediate acetylcholine-induced neurotransmission and five mAChR subtypes (M1-M5) have been identified. Among them, M1 mAChR is widely expressed in the central nervous system and has been implicated in many physiological and pathological brain functions. In addition, M1 mAChR is postulated to be an important therapeutic target for AD and several other neurodegenerative diseases. In this article, we review recent progress in understanding the functional involvement of M1 mAChR in AD pathology and in developing M1 mAChR agonists for AD treatment.
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Affiliation(s)
- Shangtong Jiang
- Fujian Provincial Key Laboratory of Neurodegenerative Disease and Aging Research, Institute of Neuroscience, College of Medicine, Xiamen University, Xiamen, 361102, China
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Jolly TAD, Bateman GA, Levi CR, Parsons MW, Michie PT, Karayanidis F. Early detection of microstructural white matter changes associated with arterial pulsatility. Front Hum Neurosci 2013; 7:782. [PMID: 24302906 PMCID: PMC3831342 DOI: 10.3389/fnhum.2013.00782] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 10/29/2013] [Indexed: 11/13/2022] Open
Abstract
Increased cerebral blood flow pulsatility is common in vascular dementia and is associated with macrostructural damage to cerebral white matter or leukoaraiosis (LA). In this study, we examine whether cerebral blood flow pulsatility is associated with macrostructural and microstructural changes in cerebral white matter in older adults with no or mild LA and no evidence of dementia. Diffusion Tensor Imaging was used to measure fractional anisotropy (FA), an index of the microstructural integrity of white matter, and radial diffusivity (RaD), a measure sensitive to the integrity of myelin. When controlling for age, increased arterial pulsation was associated with deterioration in both measures of white matter microstructure but not LA severity. A stepwise multiple linear regression model revealed that arterial pulsatility index was the strongest predictor of FA (R = 0.483, adjusted R (2) = 0.220), followed by LA severity, but not age. These findings suggest that arterial pulsatility may provide insight into age-related reduction in white matter FA. Specifically, increased arterial pulsatility may increase perivascular shear stress and lead to accumulation of damage to perivascular oligodendrocytes, resulting in microstructural changes in white matter and contributing to proliferation of LA over time. Changes in cerebral blood flow pulsatility may therefore provide a sensitive index of white matter health that could facilitate the early detection of risk for perivascular white matter damage and the assessment of the effectiveness of preventative treatment targeted at reducing pulsatility.
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Affiliation(s)
- Todd A D Jolly
- Functional Neuroimaging Laboratory, Faculty of Science and IT, School of Psychology, University of Newcastle Newcastle, NSW, Australia ; Centre for Translational Neuroscience and Mental Health Research, University of Newcastle Newcastle, NSW, Australia ; Hunter Medical Research Institute Newcastle, NSW, Australia
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Wagner M, Jurcoane A, Volz S, Magerkurth J, Zanella FE, Neumann-Haefelin T, Deichmann R, Singer OC, Hattingen E. Age-related changes of cerebral autoregulation: new insights with quantitative T2'-mapping and pulsed arterial spin-labeling MR imaging. AJNR Am J Neuroradiol 2012; 33:2081-7. [PMID: 22700750 DOI: 10.3174/ajnr.a3138] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Cerebral perfusion and O(2) metabolism are affected by physiologic age-related changes. High-resolution motion-corrected quantitative T2'-imaging and PASL were used to evaluate differences in deoxygenated hemoglobin and CBF of the gray matter between young and elderly healthy subjects. Further combined T2'-imaging and PASL were investigated breathing room air and 100% O(2) to evaluate age-related changes in cerebral autoregulation. MATERIALS AND METHODS Twenty-two healthy volunteers 60-88 years of age were studied. Two scans of high-resolution motion-corrected T2'-imaging and PASL-MR imaging were obtained while subjects were either breathing room air or breathing 100% O(2). Manual and automated regions of interest were placed in the cerebral GM to extract values from the corresponding maps. Results were compared with those of a group of young healthy subjects previously scanned with the identical protocol as that used in the present study. RESULTS There was a significant decrease of cortical CBF (P < .001) and cortical T2' values (P < .001) between young and elderly healthy subjects. In both groups, T2' remained unchanged under hyperoxia compared with normoxia. Only in the younger but not in the elderly group could a significant (P = .02) hyperoxic-induced decrease of the CBF be shown. CONCLUSIONS T2'-mapping and PASL in the cerebral cortex of healthy subjects revealed a significant decrease of deoxygenated hemoglobin and of CBF with age. The constant deoxyHb level breathing 100% O(2) compared with normoxia in young and elderly GM suggests an age-appropriate cerebral autoregulation. At the younger age, hyperoxic-induced CBF decrease may protect the brain from hyperoxemia.
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Affiliation(s)
- M Wagner
- Institute of Neuroradiology, Goethe University Frankfurt am Main, Frankfurt am Main, Germany.
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Medeiros R, Kitazawa M, Caccamo A, Baglietto-Vargas D, Estrada-Hernandez T, Cribbs DH, Fisher A, LaFerla FM. Loss of muscarinic M1 receptor exacerbates Alzheimer's disease-like pathology and cognitive decline. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:980-91. [PMID: 21704011 PMCID: PMC3157199 DOI: 10.1016/j.ajpath.2011.04.041] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 03/29/2011] [Accepted: 04/22/2011] [Indexed: 02/03/2023]
Abstract
Alzheimer's disease (AD) is pathologically characterized by tau-laden neurofibrillary tangles and β-amyloid deposits. Dysregulation of cholinergic neurotransmission has been implicated in AD pathogenesis, contributing to the associated memory impairments; yet, the exact mechanisms remain to be defined. Activating the muscarinic acetylcholine M(1) receptors (M(1)Rs) reduces AD-like pathological features and enhances cognition in AD transgenic models. To elucidate the molecular mechanisms by which M(1)Rs affect AD pathophysiological features, we crossed the 3xTgAD and transgenic mice expressing human Swedish, Dutch, and Iowa triple-mutant amyloid precursor protein (Tg-SwDI), two widely used animal models, with the M(1)R(-/-) mice. Our data show that M(1)R deletion in the 3xTgAD and Tg-SwDI mice exacerbates the cognitive impairment through mechanisms dependent on the transcriptional dysregulation of genes required for memory and through acceleration of AD-related synaptotoxicity. Ablating the M(1)R increased plaque and tangle levels in the brains of 3xTgAD mice and elevated cerebrovascular deposition of fibrillar Aβ in Tg-SwDI mice. Notably, tau hyperphosphorylation and potentiation of amyloidogenic processing in the mice with AD lacking M(1)R were attributed to changes in the glycogen synthase kinase 3β and protein kinase C activities. Finally, deleting the M(1)R increased the astrocytic and microglial response associated with Aβ plaques. Our data highlight the significant role that disrupting the M(1)R plays in exacerbating AD-related cognitive decline and pathological features and provide critical preclinical evidence to justify further development and evaluation of selective M(1)R agonists for treating AD.
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Affiliation(s)
- Rodrigo Medeiros
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California
- Department of Neurobiology and Behavior, University of California, Irvine, California
| | - Masashi Kitazawa
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California
- Department of Neurobiology and Behavior, University of California, Irvine, California
| | - Antonella Caccamo
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California
- Department of Neurobiology and Behavior, University of California, Irvine, California
| | - David Baglietto-Vargas
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California
- Department of Neurobiology and Behavior, University of California, Irvine, California
| | - Tatiana Estrada-Hernandez
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California
- Department of Neurobiology and Behavior, University of California, Irvine, California
| | - David H. Cribbs
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California
- Department of Neurology, University of California, Irvine, California
| | - Avraham Fisher
- Israel Institute for Biological Research, Ness-Ziona, Israel
| | - Frank M. LaFerla
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, California
- Department of Neurobiology and Behavior, University of California, Irvine, California
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Abstract
Cerebral autoregulation aims to stabilize blood flow to the brain during variations in perfusion pressure, thus protecting the brain against the risks of low or high systemic blood pressure. This vital mechanism is severely impaired in the transgenic mouse model of Alzheimer's disease (AD) that abundantly produces amyloid-β peptide β(1-42). These observations have been extrapolated to human AD, wherein impairment of autoregulation could have important implications for the clinical management and prevention of AD. Research on cerebral autoregulation in human AD, however, has only recently become available. Contrary to the animal models, preliminary studies suggest that cerebral autoregulation is preserved in patients with AD. Further research is urgently needed to elucidate this discrepancy in the current literature, given the accumulating evidence that implicates cerebrovascular pathology in AD.
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Abstract
The ability of the brain to locally augment glucose delivery and blood flow during neuronal activation, termed neurometabolic and neurovascular coupling, respectively, is compromised in Alzheimer's disease (AD). Since perfusion deficits may hasten clinical deterioration and have been correlated with negative treatment outcome, strategies to improve the cerebral circulation should form an integral element of AD therapeutic efforts. These efforts have yielded several experimental models, some of which constitute AD models proper, others which specifically recapture the AD cerebrovascular pathology, characterized by anatomical alterations in brain vessel structure, as well as molecular changes within vascular smooth muscle cells and endothelial cells forming the blood-brain barrier. The following paper will present the elements of AD neurovascular dysfunction and review the in vitro and in vivo model systems that have served to deepen our understanding of it. It will also critically evaluate selected groups of compounds, the FDA-approved cholinesterase inhibitors and thiazolidinediones, for their ability to correct neurovascular dysfunction in AD patients and models. These and several others are emerging as compounds with pleiotropic actions that may positively impact dysfunctional cerebrovascular, glial, and neuronal networks in AD.
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Iadecola C. The overlap between neurodegenerative and vascular factors in the pathogenesis of dementia. Acta Neuropathol 2010; 120:287-96. [PMID: 20623294 DOI: 10.1007/s00401-010-0718-6] [Citation(s) in RCA: 383] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 07/03/2010] [Accepted: 07/04/2010] [Indexed: 02/07/2023]
Abstract
There is increasing evidence that cerebrovascular dysfunction plays a role not only in vascular causes of cognitive impairment but also in Alzheimer's disease (AD). Vascular risk factors and AD impair the structure and function of cerebral blood vessels and associated cells (neurovascular unit), effects mediated by vascular oxidative stress and inflammation. Injury to the neurovascular unit alters cerebral blood flow regulation, depletes vascular reserves, disrupts the blood-brain barrier, and reduces the brain's repair potential, effects that amplify the brain dysfunction and damage exerted by incident ischemia and coexisting neurodegeneration. Clinical-pathological studies support the notion that vascular lesions aggravate the deleterious effects of AD pathology by reducing the threshold for cognitive impairment and accelerating the pace of the dementia. In the absence of mechanism-based approaches to counteract cognitive dysfunction, targeting vascular risk factors and improving cerebrovascular health offers the opportunity to mitigate the impact of one of the most disabling human afflictions.
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Claassen JAHR, Diaz-Arrastia R, Martin-Cook K, Levine BD, Zhang R. Altered cerebral hemodynamics in early Alzheimer disease: a pilot study using transcranial Doppler. J Alzheimers Dis 2009; 17:621-9. [PMID: 19433892 DOI: 10.3233/jad-2009-1079] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Cerebrovascular disease may contribute to the development and progression of Alzheimer's disease (AD). This study investigated whether impairments in cerebral hemodynamics can be detected in early-stage AD. Nine patients with mild AD and eight cognitively normal controls matched for age underwent brain magnetic resonance imaging and neuropsychological evaluation, followed by assessment of steady-state cerebral blood flow velocity (CBFV, transcranial Doppler), blood pressure (BP, Finapres), and cerebrovascular resistance index (BP/CBFV). Cerebral hemodynamics were quantified using spectral and transfer function analysis of BP and CBFV in rest, during standing up after squat, and during repeated squat-stand maneuvers. Compared to controls, AD patients had lower CBFV and higher cerebrovascular resistance index, unexplained by brain atrophy. Low-frequency variability of BP was enhanced, suggesting impaired arterial baroreflex function. However, CBFV variability was reduced despite enhanced BP variability, and dynamic cerebral autoregulation was not impaired. In conclusion, despite a distinct pattern of altered cerebral hemodynamics, AD patients may have normal autoregulation. However, the challenges for autoregulation in AD are higher, as our data show enhanced BP fluctuations. Increased cerebral vasoconstriction or reduced vasomotion also may attenuate CBFV variability.
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Affiliation(s)
- Jurgen A H R Claassen
- Department of Geriatric Medicine, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
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Belohlavek M, Jiamsripong P, Calleja AM, McMahon EM, Maarouf CL, Kokjohn TA, Chaffin TL, Vedders LJ, Garami Z, Beach TG, Sabbagh MN, Roher AE. Patients with Alzheimer disease have altered transmitral flow: echocardiographic analysis of the vortex formation time. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2009; 28:1493-1500. [PMID: 19854964 DOI: 10.7863/jum.2009.28.11.1493] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
OBJECTIVE There is considerable epidemiologic evidence that Alzheimer disease (AD) is linked to cardiovascular risk factors and associated with an increased risk of symptomatic left ventricular (LV) dysfunction. Formation of a vortex alongside a diastolic jet signifies an efficient blood transport mechanism. The vortex formation time (VFT) is an index of optimal conditions for vortex formation. We hypothesized that AD and its associated cardiovascular risk factors impair diastolic transmitral flow efficiency and, therefore, shift the VFT value out of its optimal range. METHODS Echocardiographic studies were performed on 45 participants in total: 22 patients with AD diagnosed according to the American Psychiatric Association's criteria and 23 age-matched individuals as a control group with cognitive function within normal limits. RESULTS The echocardiographic ratio of the early to atrial phases of the LV filling velocities was significantly lower in the AD group (mean +/- SD, 0.67 +/- 14) when compared with the control individuals (0.79 +/- 0.14; P = .003). The interventricular septum diastolic thickness, left ventricular posterior wall diastolic thickness, and right ventricular end-diastolic diameter were significantly higher in the AD group (P <or= 0.04). The mitral annular diameters in the control and AD groups were nearly identical (P = .725). The time-velocity integral of the E wave had a lower value in the AD group than in the control group (P = .05), whereas the VFT was significantly lower in the AD group (P = .018). CONCLUSIONS Our study suggests that patients with AD have impaired transmitral flow efficiency of diastolic filling, as measured by the VFT, compared with age-matched control individuals.
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Affiliation(s)
- Marek Belohlavek
- Translational Ultrasound Research Laboratory, Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona, USA
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Henry-Feugeas MC. Assessing cerebrovascular contribution to late dementia of the Alzheimer's type: the role of combined hemodynamic and structural MR analysis. J Neurol Sci 2009; 283:44-8. [PMID: 19268312 DOI: 10.1016/j.jns.2009.02.325] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The critical question as to the respective role of Alzheimer's disease (AD) and cerebrovascular disease in dementia of the Alzheimer's type (DAT), the most common form of dementia, is still debated. But there has been considerable progress in understanding cerebral hemodynamics and the relationship between structural brain damage and cognitive decline, in routine neuro imaging techniques. These advances now allow the proposition of a novel MR classification of DAT including indicators of both cerebrovascular function and regional brain atrophy. MR indicators of windkessel function include the arterial pulsatility index, the intracranial blood stroke volume, the cerebral relative venous outflow rates and a relative index of craniospinal compliance. MR indicators of vascular conduct function include total arterial and superficial venous flow rates that are closely related to brain metabolism. Structural MR sequences allow the detection of structural markers of windkessel dysfunction and, beyond the non specific hippocampal atrophy, a more extensive AD-like MR pattern of atrophy. The first illustration of this MR classification in elderly patients that later progressed to dementia converges with recent neuropathological observations to suggest that the major enemy to combat in late-life dementia is not AD but cerebrovascular dysfunction.
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Affiliation(s)
- Marie Cécile Henry-Feugeas
- Department of Radiology, Bichat-Claude Bernard University Hospital, AP-HP, 46 rue Henri Huchard, 75877 Paris cedex 18, France.
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Dhoat S, Ali K, Bulpitt CJ, Rajkumar C. Vascular compliance is reduced in vascular dementia and not in Alzheimer's disease. Age Ageing 2008; 37:653-9. [PMID: 18703522 DOI: 10.1093/ageing/afn158] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVE to determine whether functional changes in the vasculature differ between Alzheimer's disease (AD) and vascular dementia (VAD). DESIGN we determined vascular stiffness in patients with a clinical and radiological diagnosis of either AD or VAD and compared them to normal age- and sex-matched controls. METHODS In all, 16 patients with late onset AD, 13 subjects with VAD and 16 age- and sex-matched controls were recruited to this study. Central arterial compliance (CAC), augmentation index (AI) and pulse wave velocity (PWV) (measures of arterial stiffness) were measured. RESULTS the mean age was 77.7 +/- 8.3 years (mean +/- SD) in the AD group, 79.7 +/- 8.9 years in the VAD group and 76.4 +/- 6.9 in the controls (P = 0.44). CAC was significantly lower in subjects with VAD compared to both the AD and the control groups (0.57 +/- 0.46 ml/mm Hg versus 1.12 +/- 0.57 and 1.1 +/- 0.47 ml/mm Hg respectively, P = 0.01). AI was significantly higher in the subjects with VAD compared to both the AD and the control groups (13.3 +/- 9.0 versus 3.5 +/- 11.4 and 4.2 +/- 9.7% respectively, P = 0.03). PWV in the muscular and elastic arteries were not statistically different between the three groups but tended to be highest in the VAD group for carotid-radial measurements. CONCLUSIONS the reduced CAC and increased AI in VAD subjects indicate that the disease process is associated with less vascular compliance of the large elastic arteries in these patients, but not in patients with AD.
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Affiliation(s)
- Sasha Dhoat
- Faculty of Medicine, Imperial College, London, UK
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Henry-Feugeas MC, Onen F, Claeys ES. Classifying late-onset dementia with MRI: is arteriosclerotic brain degeneration the most common cause of Alzheimer's syndrome? Clin Interv Aging 2008; 3:187-99. [PMID: 18488889 PMCID: PMC2544365 DOI: 10.2147/cia.s2537] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Our aim was to use early magnetic resonance imaging (MRI) to investigate the causes of cognitive decline in elderly people with mild cognitive impairment (MCI). Baseline structural and flow quantification MR sequences, and clinical and neuropsychological follow-up for at least two years, were performed on 62 elderly subjects with MCI. Of these subjects, 17 progressed to dementia, and 15 of these progressed to dementia of the Alzheimer type (DAT). Conversion to clinically diagnosed DAT was related to six distinct MR profiles, including one profile suggesting severe AD (20% of these converters) and five profiles suggesting severe cerebrovascular dysfunction. Two profiles suggested arteriosclerotic brain degeneration, one profile suggested severe venous windkessel dysfunction, and two suggested marked cerebral hypoperfusion associated with very low craniospinal compliance or marked brain atrophy. As compared with vascular MR type converters, AD MR type converters showed high executive and mobility predementia performances. Severe whole anteromesial temporal atrophy and predominantly left brain atrophy on visual MR analysis was only observed in AD MR type converters. In conclusion, these observations enhance the pathogenic complexity of the Alzheimer syndrome, and suggest that the role of arteriosclerotic brain degeneration in late life dementia is underestimated.
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The venous manifestations of pulse wave encephalopathy: windkessel dysfunction in normal aging and senile dementia. Neuroradiology 2008; 50:491-7. [DOI: 10.1007/s00234-008-0374-x] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Accepted: 02/15/2008] [Indexed: 12/23/2022]
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Fleisher AS, Podraza KM, Bangen KJ, Taylor C, Sherzai A, Sidhar K, Liu TT, Dale AM, Buxton RB. Cerebral perfusion and oxygenation differences in Alzheimer's disease risk. Neurobiol Aging 2008; 30:1737-48. [PMID: 18325636 DOI: 10.1016/j.neurobiolaging.2008.01.012] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Revised: 12/08/2007] [Accepted: 01/18/2008] [Indexed: 10/22/2022]
Abstract
Functional MRI has demonstrated differences in response to memory performance based on risk for Alzheimer's disease (AD). The current study compared blood oxygen level dependent (BOLD) functional MRI response with arterial spin labeling (ASL) perfusion response during an associative encoding task and resting perfusion signal in different risk groups for AD. Thirteen individuals with a positive family history of AD and at least one copy of the apolipoprotien E epsilon4 (APOE4) gene (high risk) were compared to ten individuals without these risk factors (low risk). In the medial temporal lobes (MTLs) the high risk group had an elevated level of resting perfusion, and demonstrated decreased fractional BOLD and perfusion responses to the encoding task. However, there was no difference in the absolute cerebral blood flow during the task. These data demonstrate that individuals with increased risk for Alzheimer's disease have elevated MTL resting cerebral blood flow, which significantly influences apparent differences in BOLD activations. BOLD activations should be interpreted with caution, and do not necessarily reflect differences in neuronal activation.
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Affiliation(s)
- Adam S Fleisher
- University of California at San Diego, Department of Neuroscience, La Jolla, CA 92037-0949, United States.
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Altered morphology and 3D architecture of brain vasculature in a mouse model for Alzheimer's disease. Proc Natl Acad Sci U S A 2008; 105:3587-92. [PMID: 18305170 DOI: 10.1073/pnas.0709788105] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Substantial evidence from epidemiological, pathological, and clinical reports suggests that vascular factors are critical in the pathogenesis of Alzheimer's disease (AD), and changes in blood flow are currently the most reliable indicators of the disease. We previously reported that older APP23 transgenic (tg) mice have significant blood flow alterations correlated with structural modifications of blood vessels. For the present study, our objective was to analyze the age-dependent morphological and architectural changes of the cerebral vasculature of APP23 tg mice. To visualize the 3D arrangement of the entire brain vasculature, we used vascular corrosion casts. Already at young ages, when typically parenchymal amyloid plaques are not yet present, APP23 tg mice had significant alterations, particularly of the microvasculature, often accompanied by small deposits attached to the vessels. In older animals, vasculature abruptly ended at amyloid plaques, resulting in holes. Often, small deposits were sitting near or at the end of truncated vessels. Between such holes, the surrounding vascular array appeared more dense and showed features typical for angiogenesis. We propose that small amyloid aggregates associated with the microvasculature lead to morphological and architectural alterations of the vasculature, resulting in altered local blood flow. The characteristic early onset of vascular alterations suggests that imaging blood flow and/or vasculature architecture could be used as a tool for early diagnosis of the disease and to monitor therapies.
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Henry-Feugeas MC. Alzheimer’s disease in late-life dementia: A minor toxic consequence of devastating cerebrovascular dysfunction. Med Hypotheses 2008; 70:866-75. [PMID: 17825499 DOI: 10.1016/j.mehy.2007.07.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Accepted: 07/16/2007] [Indexed: 11/24/2022]
Abstract
Alzheimer's disease (AD) is thought to be the most common cause of late-life dementia. But pure AD is infrequent whereas AD pathology is often insufficient to explain dementia in the elderly. Conversely, cerebrovascular disease is omnipresent and the crucial role of microvascular alterations increasingly recognized in late dementia or "Alzheimer syndrome". Pathomechanisms of vascular cognitive impairment are still debated but recent data indicate that the initial concept of chronic low grade cerebral hypoxia should not have been abandoned. Thus, it is proposed that windkessel dysfunction is the missing link between vascular and craniospinal senescence on the one hand, and chronic low grade cerebral hypoxia, "senile brain degeneration" and "Alzheimer syndrome" on the other hand. An age-related decrease in the buffering capacity of both the vessels and the craniospinal cavity favours cerebral hypoxia; due to increased capillary pulsatility with disturbances in capillary exchanges or due to a marked reduction in craniospinal compliance with a mechanical reduction in cerebral arterial inflow. "Invisible" windkessel dysfunction, most often related to "hardening of the arteries" may be the most frequent pathomechanism of late-onset dementia whereas associated mild or moderate AD may be merely a toxic manifestation of a primarily hypoxic disease. Structural patterns of arteriosclerotic dementia fit well with an underlying arterial windkessel dysfunction: with secondary mechanical damage to the cerebral small vessels and the brain and predominantly deep hypoxia. The clinical significance of leukoaraïosis, small foci of necrosis, ventricular dilatation, hippocampal and cortical atrophy is in good agreement with their value as indirect markers of windkessel dysfunction. An age-related "invisible" reduction in craniospinal compliance may also contribute to the associations between heart failure, arterial hypotension and cognitive impairment in the elderly and to the high percentage of dementia of unknown origin in the very old. Both neuropathological and clinical overlap between AD and windkessel dysfunction can explain that cerebrovascular dysfunction remains misdiagnosed for AD in the elderly. Evidence of the key role of cerebrovascular dysfunction should markedly facilitate and widen therapeutic research in late-life dementia. Routine MRI including direct assessment of intracranial dynamics should be increasingly used to define etiological subtypes of the "Alzheimer syndrome" and develop a well-targeted therapeutic strategy.
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Affiliation(s)
- M C Henry-Feugeas
- Department of Radiology, Bichat-Claude Bernard University Hospital, AP-HP, Paris Cedex 18, France.
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Stivaros SM, Jackson A. Changing concepts of cerebrospinal fluid hydrodynamics: role of phase-contrast magnetic resonance imaging and implications for cerebral microvascular disease. Neurotherapeutics 2007; 4:511-22. [PMID: 17599715 PMCID: PMC7479718 DOI: 10.1016/j.nurt.2007.04.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Phase-contrast magnetic resonance imaging (PC-MRI) or flow-sensitive MRI can be used to noninvasively measure intracranial vascular and CSF flow. Monro-Kellie homeostasis is the complex compensatory mechanism for the increase in intracranial blood volume during systole. Through PC-MRI techniques, our understanding of Monro-Kellie homeostasis and the associated intracranial hydrodynamics has greatly improved. Failure of this homeostatic mechanism has been implicated in a wide range of cerebral disorders, including vascular and Alzheimer's dementia, late-onset depression, benign and secondary intracranial hypertension, communicating and normal pressure hydrocephalus, and age-related white matter changes. The most common mode of homeostatic failure is due to vascular disease with decreased cerebral arterial compliance. This has wide-reaching implications in the investigation of patients with cerebral vascular disease. Here we discuss the role of PC-MRI in the study of cerebral hydrodynamics and the current understanding of Monro-Kellie homeostasis in both healthy and disease states. Quantitative assessment of the changes in this homeostatic mechanism using PC-MRI has important implications in the development of biomarkers of vascular involvement in disease with application in diagnosis, treatment planning, phenotype identification, and outcome assessment in clinical trials.
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Affiliation(s)
- Stavros Michael Stivaros
- Imaging Science and Biomedical Engineering, The Medical School, University of Manchester, Oxford Road, M13 9PT UK
| | - Alan Jackson
- Imaging Science and Biomedical Engineering, The Medical School, University of Manchester, Oxford Road, M13 9PT UK
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