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Madsen LS, Kjeldsen PL, Ismail R, Parbo P, Østergaard L, Brooks DJ, Eskildsen SF. Capillary dysfunction in healthy elderly APOE ε4 carriers with raised brain Aβ deposition. Alzheimers Dement 2024; 20:459-471. [PMID: 37679610 PMCID: PMC10917038 DOI: 10.1002/alz.13461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/26/2023] [Accepted: 08/13/2023] [Indexed: 09/09/2023]
Abstract
INTRODUCTION Capillary dysfunction, characterized by disturbances in capillary blood flow distribution, might be an overlooked factor in the development of Alzheimer's disease (AD). This study investigated microvascular blood flow in preclinical and prodromal AD individuals. METHODS Using dynamic susceptibility contrast magnetic resonance imaging and positron emission tomography, we examined alterations in microvascular circulation and levels of Aβ deposition in two independent cohorts of APOE ε4 carriers. RESULTS Capillary dysfunction was elevated in both prodromal and preclinical AD individuals compared to age-matched controls. Additionally, the prodromal group exhibited higher levels of capillary dysfunction compared to the preclinical group. DISCUSSION These findings suggest that capillary dysfunction can be detected at the preclinical stage of AD and indicates a worsening of capillary dysfunction throughout the AD continuum. Understanding the interaction between capillary dysfunction and Aβ could provide insights into the relationship between cardiovascular risk factors and the development of AD. HIGHLIGHTS Alzheimer's disease (AD) is associated with disturbances in microvascular circulation. Capillary dysfunction can be detected in preclinical AD. As cognitive symptoms progress in prodromal AD, capillary dysfunction worsens. Capillary dysfunction may impede the clearance of beta-amyloid (Aβ). Capillary dysfunction might contribute to the development of AD.
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Affiliation(s)
- Lasse S. Madsen
- Center of Functionally Integrative NeuroscienceDepartment of Clinical MedicineAarhus UniversityAarhusDenmark
- Department of Nuclear Medicine and PET‐CentreAarhus University HospitalAarhusDenmark
| | - Pernille L. Kjeldsen
- Department of Nuclear Medicine and PET‐CentreAarhus University HospitalAarhusDenmark
| | - Rola Ismail
- Department of Nuclear MedicineSygehus LillebaeltVejleDenmark
| | - Peter Parbo
- Department of Nuclear MedicineOdense University HospitalOdenseDenmark
| | - Leif Østergaard
- Center of Functionally Integrative NeuroscienceDepartment of Clinical MedicineAarhus UniversityAarhusDenmark
- Department of NeuroradiologyAarhus University HospitalAarhusDenmark
| | - David J. Brooks
- Department of Nuclear Medicine and PET‐CentreAarhus University HospitalAarhusDenmark
- Institute of Translational and Clinical ResearchUniversity of Newcastle upon TyneNewcastle upon TyneUK
| | - Simon F. Eskildsen
- Center of Functionally Integrative NeuroscienceDepartment of Clinical MedicineAarhus UniversityAarhusDenmark
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Paulson OB, Schousboe A, Hultborn H. The history of Danish neuroscience. Eur J Neurosci 2023; 58:2893-2960. [PMID: 37477973 DOI: 10.1111/ejn.16062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 05/04/2023] [Accepted: 05/29/2023] [Indexed: 07/22/2023]
Abstract
The history of Danish neuroscience starts with an account of impressive contributions made at the 17th century. Thomas Bartholin was the first Danish neuroscientist, and his disciple Nicolaus Steno became internationally one of the most prominent neuroscientists in this period. From the start, Danish neuroscience was linked to clinical disciplines. This continued in the 19th and first half of the 20th centuries with new initiatives linking basic neuroscience to clinical neurology and psychiatry in the same scientific environment. Subsequently, from the middle of the 20th century, basic neuroscience was developing rapidly within the preclinical university sector. Clinical neuroscience continued and was even reinforced during this period with important translational research and a close co-operation between basic and clinical neuroscience. To distinguish 'history' from 'present time' is not easy, as many historical events continue in present time. Therefore, we decided to consider 'History' as new major scientific developments in Denmark, which were launched before the end of the 20th century. With this aim, scientists mentioned will have been born, with a few exceptions, no later than the early 1960s. However, we often refer to more recent publications in documenting the developments of initiatives launched before the end of the last century. In addition, several scientists have moved to Denmark after the beginning of the present century, and they certainly are contributing to the present status of Danish neuroscience-but, again, this is not the History of Danish neuroscience.
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Affiliation(s)
- Olaf B Paulson
- Neurobiology Research Unit, Department of Neurology, Rigshospitalet, 9 Blegdamsvej, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Arne Schousboe
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hans Hultborn
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Jensen M, Zeller T, Twerenbold R, Thomalla G. Circulating cardiac biomarkers, structural brain changes, and dementia: Emerging insights and perspectives. Alzheimers Dement 2023; 19:1529-1548. [PMID: 36735636 DOI: 10.1002/alz.12926] [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: 11/28/2022] [Accepted: 12/19/2022] [Indexed: 02/04/2023]
Abstract
Diseases of the heart and brain are strongly linked to each other, and cardiac dysfunction is associated with cognitive decline and dementia. This link between cardiovascular disease and dementia offers opportunities for dementia prevention through prevention and treatment of cardiovascular risk factors and heart disease. Increasing evidence suggests the clinical utility of cardiac biomarkers as risk markers for structural brain changes and cognitive impairment. We propose the hypothesis that structural brain changes are the link between impaired cardiac function, as captured by blood-based cardiac biomarkers, and cognitive impairment. This review provides an overview of the literature and illustrates emerging insights into the association of markers of hemodynamic stress (natriuretic peptides) and markers of myocardial injury (cardiac troponins) with imaging findings of brain damage and cognitive impairment or dementia. Based on these findings, we discuss potential pathophysiological mechanisms underlying the association of cardiac biomarkers with structural brain changes and dementia. We suggest testable hypotheses and a research plan to close the gaps in understanding the mechanisms linking vascular damage and neurodegeneration, and to pave the way for targeted effective interventions for dementia prevention. From a clinical perspective, cardiac biomarkers open the window for early identification of patients at risk of dementia, who represent a target population for preventive interventions targeting modifiable cardiovascular risk factors to avert cognitive decline and dementia.
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Affiliation(s)
- Märit Jensen
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK e.V.), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Tanja Zeller
- German Centre for Cardiovascular Research (DZHK e.V.), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany.,University Center of Cardiovascular Science, University Heart and Vascular Center Hamburg, Clinic for Cardiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Raphael Twerenbold
- German Centre for Cardiovascular Research (DZHK e.V.), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany.,University Center of Cardiovascular Science, University Heart and Vascular Center Hamburg, Clinic for Cardiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Götz Thomalla
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK e.V.), Partner Site Hamburg/Kiel/Lübeck, Hamburg, Germany
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Guo XY, Kwon HJ, Rhee HY, Park S, Cho AR, Ryu CW, Jahng GH. Microvascular morphology alteration using relaxation rate change with gadolinium-based magnetic resonance imaging contrast agent in patients with Alzheimer's disease. Quant Imaging Med Surg 2023; 13:1-16. [PMID: 36620129 PMCID: PMC9816741 DOI: 10.21037/qims-22-524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 09/29/2022] [Indexed: 11/30/2022]
Abstract
Background Conventional magnetic resonance imaging (MRI) techniques cannot demonstrate microvascular alterations in mild Alzheimer's disease (AD). Thus, the diagnosis of microvascular pathology commonly relies on postmortem. The purpose of this study was to evaluate alterations of microvascular structures in patients with AD using a 3T clinical MRI system with a commercially available contrast agent. Methods Eleven patients with AD and 11 cognitively normal (CN) controls were included in this cross-sectional prospective study. R2 and R2* relaxation rate changes (∆R2 and ∆R2*) before and after a Gadolinium (Gd)-based contrast agent injection were calculated from images obtained with a multi-echo turbo spin-echo sequence and multi-echo gradient-echo sequence to obtain microvascular index maps of blood volume fraction (BVf), mean vessel diameter (mVD), vessel size index (VSI), mean vessel density (Q), and microvessel-weighted imaging (MvWI). Two-sample t-test was used to compare those values between the two groups. Correlation analysis was performed to evaluate the relationship between those values and age. Results BVfs at the corpus callosum and at the thalamus were significantly increased in the AD group (P=0.024 and P=0.005, respectively). BVf at the gray matter (P=0.020) and white matter area (P=0.012) were also significantly increased in the AD group compared with the CN group. MvWIs at the hippocampus and parahippocampal gyrus were significantly increased in the AD group compared with the CN group (P=0.020 and P=0.006, respectively). Voxel-based analysis showed both mVD and VSI were significantly decreased at the prefrontal lobe in the AD group. Q were not significant difference between CN and AD groups. MvWI were significantly positively correlated with age. Conclusions Microvascular index was a useful non-invasive method to evaluate microvascular morphology alteration. The microvascular morphology of AD was manifested as increasing BVf and microvessel-weighted.
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Affiliation(s)
- Xiao-Yi Guo
- Department of Medicine, Graduate School, Kyung Hee University, Seoul, Republic of Korea
| | - Hyeok Jung Kwon
- Department of Medicine, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Hak Young Rhee
- Department of Neurology, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Soonchan Park
- Department of Radiology, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Ah Rang Cho
- Department of Psychiatry, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Chang-Woo Ryu
- Department of Radiology, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Geon-Ho Jahng
- Department of Radiology, Kyung Hee University Hospital at Gangdong, College of Medicine, Kyung Hee University, Seoul, Republic of Korea
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Kang K, Jeong SY, Park K, Hahm MH, Kim J, Lee H, Kim C, Yun E, Han J, Yoon U, Lee S. Distinct cerebral cortical perfusion patterns in idiopathic normal-pressure hydrocephalus. Hum Brain Mapp 2022; 44:269-279. [PMID: 36102811 PMCID: PMC9783416 DOI: 10.1002/hbm.25974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/29/2022] [Accepted: 05/12/2022] [Indexed: 02/05/2023] Open
Abstract
The aims of the study are to evaluate idiopathic normal-pressure hydrocephalus (INPH)-related cerebral blood flow (CBF) abnormalities and to investigate their relation to cortical thickness in INPH patients. We investigated cortical CBF utilizing surface-based early-phase 18 F-florbetaben (E-FBB) PET analysis in two groups: INPH patients and healthy controls. All 39 INPH patients and 20 healthy controls were imaged with MRI, including three-dimensional volumetric images, for automated surface-based cortical thickness analysis across the entire brain. A subgroup with 37 participants (22 INPH patients and 15 healthy controls) that also underwent 18 F-fluorodeoxyglucose (FDG) PET imaging was further analyzed. Compared with age- and gender-matched healthy controls, INPH patients showed statistically significant hyperperfusion in the high convexity of the frontal and parietal cortical regions. Importantly, within the INPH group, increased perfusion correlated with cortical thickening in these regions. Additionally, significant hypoperfusion mainly in the ventrolateral frontal cortex, supramarginal gyrus, and temporal cortical regions was observed in the INPH group relative to the control group. However, this hypoperfusion was not associated with cortical thinning. A subgroup analysis of participants that also underwent FDG PET imaging showed that increased (or decreased) cerebral perfusion was associated with increased (or decreased) glucose metabolism in INPH. A distinctive regional relationship between cerebral cortical perfusion and cortical thickness was shown in INPH patients. Our findings suggest distinct pathophysiologic mechanisms of hyperperfusion and hypoperfusion in INPH patients.
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Affiliation(s)
- Kyunghun Kang
- Department of Neurology, School of MedicineKyungpook National UniversityDaeguSouth Korea
| | - Shin Young Jeong
- Department of Nuclear Medicine, School of MedicineKyungpook National UniversityDaeguSouth Korea
| | - Ki‐Su Park
- Department of Neurosurgery, School of MedicineKyungpook National UniversityDaeguSouth Korea
| | - Myong Hun Hahm
- Department of Radiology, School of MedicineKyungpook National UniversityDaeguSouth Korea
| | - Jaeil Kim
- School of Computer Science and EngineeringKyungpook National UniversityDaeguSouth Korea
| | - Ho‐Won Lee
- Department of Neurology, School of MedicineKyungpook National UniversityDaeguSouth Korea,Brain Science and Engineering InstituteKyungpook National UniversityDaeguSouth Korea
| | - Chi‐Hun Kim
- Department of NeurologyHallym University Sacred Heart HospitalAnyangSouth Korea
| | - Eunkyeong Yun
- Department of Biomedical EngineeringDaegu Catholic UniversityGyeongsan‐siSouth Korea
| | - Jaehwan Han
- Department of Biomedical EngineeringDaegu Catholic UniversityGyeongsan‐siSouth Korea
| | - Uicheul Yoon
- Department of Biomedical EngineeringDaegu Catholic UniversityGyeongsan‐siSouth Korea
| | - Sang‐Woo Lee
- Department of Nuclear Medicine, School of MedicineKyungpook National UniversityDaeguSouth Korea
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Perera C, Tolomeo D, Baker RR, Ohene Y, Korsak A, Lythgoe MF, Thomas DL, Wells JA. Investigating changes in blood-cerebrospinal fluid barrier function in a rat model of chronic hypertension using non-invasive magnetic resonance imaging. Front Mol Neurosci 2022; 15:964632. [PMID: 36117909 PMCID: PMC9478509 DOI: 10.3389/fnmol.2022.964632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/02/2022] [Indexed: 12/03/2022] Open
Abstract
Chronic hypertension is a major risk factor for the development of neurodegenerative disease, yet the etiology of hypertension-driven neurodegeneration remains poorly understood. Forming a unique interface between the systemic circulation and the brain, the blood-cerebrospinal fluid barrier (BCSFB) at the choroid plexus (CP) has been proposed as a key site of vulnerability to hypertension that may initiate downstream neurodegenerative processes. However, our ability to understand BCSFB's role in pathological processes has, to date, been restricted by a lack of non-invasive functional measurement techniques. In this work, we apply a novel Blood-Cerebrospinal Fluid Barrier Arterial Spin Labeling (BCSFB-ASL) Magnetic resonance imaging (MRI) approach with the aim of detecting possible derangement of BCSFB function in the Spontaneous Hypertensive Rat (SHR) model using a non-invasive, translational technique. SHRs displayed a 36% reduction in BCSFB-mediated labeled arterial water delivery into ventricular cerebrospinal fluid (CSF), relative to normotensive controls, indicative of down-regulated choroid plexus function. This was concomitant with additional changes in brain fluid biomarkers, namely ventriculomegaly and changes in CSF composition, as measured by T1 lengthening. However, cortical cerebral blood flow (CBF) measurements, an imaging biomarker of cerebrovascular health, revealed no measurable change between the groups. Here, we provide the first demonstration of BCSFB-ASL in the rat brain, enabling non-invasive assessment of BCSFB function in healthy and hypertensive rats. Our data highlights the potential for BCSFB-ASL to serve as a sensitive early biomarker for hypertension-driven neurodegeneration, in addition to investigating the mechanisms relating hypertension to neurodegenerative outcomes.
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Affiliation(s)
- Charith Perera
- Division of Medicine, UCL Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom
| | - Daniele Tolomeo
- Division of Medicine, UCL Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom
| | - Rebecca R. Baker
- Division of Medicine, UCL Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom
| | - Yolanda Ohene
- Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, United Kingdom
- Geoffrey Jefferson Brain Research Centre, University of Manchester, Manchester, United Kingdom
| | - Alla Korsak
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Mark F. Lythgoe
- Division of Medicine, UCL Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom
| | - David L. Thomas
- Neuroradiological Academic Unit, Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology, London, United Kingdom
- Dementia Research Centre, UCL Queen Square Institute of Neurology, London, United Kingdom
- Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom
| | - Jack A. Wells
- Division of Medicine, UCL Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom
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Jullienne A, Quan R, Szu JI, Trinh MV, Behringer EJ, Obenaus A. Progressive Vascular Abnormalities in the Aging 3xTg-AD Mouse Model of Alzheimer’s Disease. Biomedicines 2022; 10:biomedicines10081967. [PMID: 36009514 PMCID: PMC9405684 DOI: 10.3390/biomedicines10081967] [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: 06/22/2022] [Revised: 08/01/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
Vascular dysfunction and structural abnormalities in Alzheimer’s disease (AD) are known to contribute to the progression of the pathology, and studies have tended to ignore the role of the vasculature in AD progression. We utilized the 3xTg-AD mouse model of AD to examine individual cerebral vessels and the cortical vascular network across the lifespan. Our vessel painting approach was used to label the entire cortical vasculature, followed by epifluorescence microscopy. The middle cerebral artery (MCA) tree was assessed with confocal microscopy, and a new method was developed to assess branching patterns as a measure of aging-related changes. We found that vascular remodeling was profoundly altered at 4–6 months of age, when the 3xTg-AD mouse is known to transition to cognitive impairment and Aβ deposition in both sexes. Analysis of vascular features (density, junctions, length) of the MCA territory highlighted sex-dependent differences across the 3xTg-AD mouse lifespan, with no alterations in branching patterns. Our current cerebrovascular angioarchitectural analyses demonstrate progressive alterations in individual cortical vessels, as well as in the vascular network of the cortex. These new findings advance our understanding of brain anatomy and physiology in the 3xTg-AD mouse, while potentially identifying unique diagnostic signatures of AD progression.
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Affiliation(s)
- Amandine Jullienne
- Department of Pediatrics, University of California, Irvine, CA 92697, USA
| | - Ryan Quan
- Department of Pediatrics, University of California, Irvine, CA 92697, USA
| | - Jenny I. Szu
- Department of Pediatrics, University of California, Irvine, CA 92697, USA
| | - Michelle V. Trinh
- Department of Pediatrics, University of California, Irvine, CA 92697, USA
| | - Erik J. Behringer
- Department of Basic Sciences, Loma Linda University, Loma Linda, CA 92350, USA
| | - Andre Obenaus
- Department of Pediatrics, University of California, Irvine, CA 92697, USA
- Department of Basic Sciences, Loma Linda University, Loma Linda, CA 92350, USA
- Correspondence:
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Saiyasit N, Butlig EAR, Chaney SD, Traylor MK, Hawley NA, Randall RB, Bobinger HV, Frizell CA, Trimm F, Crook ED, Lin M, Hill BD, Keller JL, Nelson AR. Neurovascular Dysfunction in Diverse Communities With Health Disparities-Contributions to Dementia and Alzheimer's Disease. Front Neurosci 2022; 16:915405. [PMID: 35844216 PMCID: PMC9279126 DOI: 10.3389/fnins.2022.915405] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/31/2022] [Indexed: 12/13/2022] Open
Abstract
Alzheimer's disease and related dementias (ADRD) are an expanding worldwide crisis. In the absence of scientific breakthroughs, the global prevalence of ADRD will continue to increase as more people are living longer. Racial or ethnic minority groups have an increased risk and incidence of ADRD and have often been neglected by the scientific research community. There is mounting evidence that vascular insults in the brain can initiate a series of biological events leading to neurodegeneration, cognitive impairment, and ADRD. We are a group of researchers interested in developing and expanding ADRD research, with an emphasis on vascular contributions to dementia, to serve our local diverse community. Toward this goal, the primary objective of this review was to investigate and better understand health disparities in Alabama and the contributions of the social determinants of health to those disparities, particularly in the context of vascular dysfunction in ADRD. Here, we explain the neurovascular dysfunction associated with Alzheimer's disease (AD) as well as the intrinsic and extrinsic risk factors contributing to dysfunction of the neurovascular unit (NVU). Next, we ascertain ethnoregional health disparities of individuals living in Alabama, as well as relevant vascular risk factors linked to AD. We also discuss current pharmaceutical and non-pharmaceutical treatment options for neurovascular dysfunction, mild cognitive impairment (MCI) and AD, including relevant studies and ongoing clinical trials. Overall, individuals in Alabama are adversely affected by social and structural determinants of health leading to health disparities, driven by rurality, ethnic minority status, and lower socioeconomic status (SES). In general, these communities have limited access to healthcare and healthy food and other amenities resulting in decreased opportunities for early diagnosis of and pharmaceutical treatments for ADRD. Although this review is focused on the current state of health disparities of ADRD patients in Alabama, future studies must include diversity of race, ethnicity, and region to best be able to treat all individuals affected by ADRD.
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Affiliation(s)
- Napatsorn Saiyasit
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Evan-Angelo R. Butlig
- Department of Neurology, Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, Intellectual and Developmental Disabilities Research Center, University of California, Los Angeles, Los Angeles, CA, United States
| | - Samantha D. Chaney
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Miranda K. Traylor
- Department of Health, Kinesiology, and Sport, University of South Alabama, Mobile, AL, United States
| | - Nanako A. Hawley
- Department of Psychology, University of South Alabama, Mobile, AL, United States
| | - Ryleigh B. Randall
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Hanna V. Bobinger
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Carl A. Frizell
- Department of Physician Assistant Studies, University of South Alabama, Mobile, AL, United States
| | - Franklin Trimm
- College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Errol D. Crook
- Department of Internal Medicine, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Mike Lin
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
| | - Benjamin D. Hill
- Department of Psychology, University of South Alabama, Mobile, AL, United States
| | - Joshua L. Keller
- Department of Health, Kinesiology, and Sport, University of South Alabama, Mobile, AL, United States
| | - Amy R. Nelson
- Department of Physiology and Cell Biology, College of Medicine, University of South Alabama, Mobile, AL, United States
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Fukui K, Kimura S, Kato Y, Kohno M. Effects of far infrared light on Alzheimer's disease-transgenic mice. PLoS One 2021; 16:e0253320. [PMID: 34138944 PMCID: PMC8211253 DOI: 10.1371/journal.pone.0253320] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 06/02/2021] [Indexed: 11/19/2022] Open
Abstract
Far infrared light has been used in many medical procedures. However, the detailed biological mechanisms of infrared light's effects have not yet been elucidated. Many researchers have pointed out the thermal effects of treatments such as infrared saunas, which are known to increase blood flow. Alzheimer's disease (AD) is associated with gradual decreases in brain blood flow and resulting dementia. In this study, we attempted to clarify the beneficial effects of far infrared light using the 5xFAD mouse, a transgenic model of AD. We exposed 5xFAD mice to far infrared light for 5 months. Among the far infrared-exposed AD mice, body weights were significantly decreased, and the levels of nerve growth factor and brain-derived neurotrophic factor protein were significantly increased in selected brain areas (compared to those in non-irradiated AD mice). However, cognition and motor function (as assessed by Morris water maze and Rota Rod tests, respectively) did not differ significantly between the irradiated and non-irradiated AD mouse groups. These results indicated that exposure to far infrared light may have beneficial biological effects in AD mice. However, the experimental schedule and methods may need to be modified to obtain clearer results.
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Affiliation(s)
- Koji Fukui
- Department of Bioscience and Engineering, Molecular Cell Biology Laboratory, College of Systems Engineering and Sciences, Shibaura Institute of Technology (SIT), Minato, Japan
- Department of Functional Control Systems, Molecular Cell Biology Laboratory, Graduate School of Engineering and Science, SIT, Minato, Japan
- Department of Life Science and Technology, Tokyo Institute of Technology, Meguro, Japan
| | - Shunsuke Kimura
- Department of Bioscience and Engineering, Molecular Cell Biology Laboratory, College of Systems Engineering and Sciences, Shibaura Institute of Technology (SIT), Minato, Japan
| | - Yugo Kato
- Department of Functional Control Systems, Molecular Cell Biology Laboratory, Graduate School of Engineering and Science, SIT, Minato, Japan
| | - Masahiro Kohno
- Department of Life Science and Technology, Tokyo Institute of Technology, Meguro, Japan
- SIT Research Laboratories, The Brain Science & Life Technology Research Center, SIT, Minato, Japan
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Østergaard L. SARS CoV-2 related microvascular damage and symptoms during and after COVID-19: Consequences of capillary transit-time changes, tissue hypoxia and inflammation. Physiol Rep 2021; 9:e14726. [PMID: 33523608 PMCID: PMC7849453 DOI: 10.14814/phy2.14726] [Citation(s) in RCA: 154] [Impact Index Per Article: 51.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 12/15/2022] Open
Abstract
Corona virus disease 2019 (COVID-19) causes symptoms from multiple organs after infection by severe acute respiratory syndrome corona virus 2 (SARS CoV-2). They range from early, low blood oxygen levels (hypoxemia) without breathlessness ("silent hypoxia"), delirium, rashes, and loss of smell (anosmia), to persisting chest pain, muscle weakness and -pain, fatigue, confusion, memory problems and difficulty to concentrate ("brain fog"), mood changes, and unexpected onset of hypertension or diabetes. SARS CoV-2 affects the microcirculation, causing endothelial cell swelling and damage (endotheliitis), microscopic blood clots (microthrombosis), capillary congestion, and damage to pericytes that are integral to capillary integrity and barrier function, tissue repair (angiogenesis), and scar formation. Similar to other instances of critical illness, COVID-19 is also associated with elevated cytokine levels in the systemic circulation. This review examines how capillary damage and inflammation may contribute to these acute and persisting COVID-19 symptoms by interfering with blood and tissue oxygenation and with brain function. Undetectable by current diagnostic methods, capillary flow disturbances limit oxygen diffusion exchange in lungs and tissue and may therefore cause hypoxemia and tissue hypoxia. The review analyzes the combined effects of COVID-19-related capillary damage, pre-existing microvascular changes, and upstream vascular tone on tissue oxygenation in key organs. It identifies a vicious cycle, as infection- and hypoxia-related inflammation cause capillary function to deteriorate, which in turn accelerates hypoxia-related inflammation and tissue damage. Finally, the review addresses the effects of low oxygen and high cytokine levels in brain tissue on neurotransmitter synthesis and mood. Methods to assess capillary functions in human organs and therapeutic means to protect capillary functions and stimulate capillary bed repair may prove important for the individualized management of COVID-19 patients and targeted rehabilitation strategies.
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Affiliation(s)
- Leif Østergaard
- Neuroradiology Research UnitSection of NeuroradiologyDepartment of RadiologyAarhus University HospitalAarhusDenmark
- Center of Functionally Integrative NeuroscienceDepartment of Clinical MedicineAarhus UniversityAarhusDenmark
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Østergaard L. Blood flow, capillary transit times, and tissue oxygenation: the centennial of capillary recruitment. J Appl Physiol (1985) 2020; 129:1413-1421. [PMID: 33031017 DOI: 10.1152/japplphysiol.00537.2020] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The transport of oxygen between blood and tissue is limited by blood's capillary transit time, understood as the time available for diffusion exchange before blood returns to the heart. If all capillaries contribute equally to tissue oxygenation at all times, this physical limitation would render vasodilation and increased blood flow insufficient means to meet increased metabolic demands in the heart, muscle, and other organs. In 1920, Danish physiologist August Krogh was awarded the Nobel Prize in Physiology or Medicine for his mathematical and quantitative, experimental demonstration of a solution to this conceptual problem: capillary recruitment, the active opening of previously closed capillaries to meet metabolic demands. Today, capillary recruitment is still mentioned in textbooks. When we suspect symptoms might represent hypoxia of a vascular origin, however, we search for relevant, flow-limiting conditions in our patients and rarely ascribe hypoxia or hypoxemia to short capillary transit times. This review describes how natural changes in capillary transit-time heterogeneity (CTH) and capillary hematocrit (HCT) across open capillaries during blood flow increases can account for a match of oxygen availability to metabolic demands in normal tissue. CTH and HCT depend on a number of factors: on blood properties, including plasma viscosity, the number, size, and deformability of blood cells, and blood cell interactions with capillary endothelium; on anatomical factors including glycocalyx, endothelial cells, basement membrane, and pericytes that affect the capillary diameter; and on any external compression. The review describes how risk factor- and disease-related changes in CTH and HCT interfere with flow-metabolism coupling and tissue oxygenation and discusses whether such capillary dysfunction contributes to vascular disease pathology.
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Affiliation(s)
- Leif Østergaard
- Center of Functionally Integrative Neuroscience, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Neuroradiology Research Unit, Section of Neuroradiology, Department of Radiology, Aarhus University Hospital, Aarhus, Denmark
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