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Méndez-Flores OG, Hernández-Kelly LC, Olivares-Bañuelos TN, López-Ramírez G, Ortega A. Brain energetics and glucose transport in metabolic diseases: role in neurodegeneration. Nutr Neurosci 2024:1-12. [PMID: 38294500 DOI: 10.1080/1028415x.2024.2306427] [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: 02/01/2024]
Abstract
OBJECTIVES Neurons and glial cells are the main functional and structural elements of the brain, and the former depends on the latter for their nutritional, functional and structural organization, as well as for their energy maintenance. METHODS Glucose is the main metabolic source that fulfills energetic demands, either by direct anaplerosis or through its conversion to metabolic intermediates. Development of some neurodegenerative diseases have been related with modifications in the expression and/or function of glial glucose transporters, which might cause physiological and/or pathological disturbances of brain metabolism. In the present contribution, we summarized the experimental findings that describe the exquisite adjustment in expression and function of glial glucose transporters from physiologic to pathologic metabolism, and its relevance to neurodegenerative diseases. RESULTS A exhaustive literature review was done in order to gain insight into the role of brain energetics in neurodegenerative disease. This study made evident a critical involvement of glucose transporters and thus brain energetics in the development of neurodegenerative diseases. DISCUSSION An exquisite adjustment in the expression and function of glial glucose transporters from physiologic to pathologic metabolism is a biochemical signature of neurodegenerative diseases.
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Affiliation(s)
- Orquídea G Méndez-Flores
- División Académica de Ciencias de la Salud, Universidad Juárez Autónoma de Tabasco (UJAT), Villahermosa, México
| | - Luisa C Hernández-Kelly
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, México
| | | | - Gabriel López-Ramírez
- División Académica de Ciencias de la Salud, Universidad Juárez Autónoma de Tabasco (UJAT), Villahermosa, México
| | - Arturo Ortega
- Laboratorio de Neurotoxicología, Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Ciudad de México, México
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Fang X, Fan F, Border JJ, Roman RJ. Cerebrovascular Dysfunction in Alzheimer's Disease and Transgenic Rodent Models. JOURNAL OF EXPERIMENTAL NEUROLOGY 2024; 5:42-64. [PMID: 38434588 PMCID: PMC10906803 DOI: 10.33696/neurol.5.087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
Alzheimer's Disease (AD) and Alzheimer's Disease-Related Dementia (ADRD) are the primary causes of dementia that has a devastating effect on the quality of life and is a tremendous economic burden on the healthcare system. The accumulation of extracellular beta-amyloid (Aβ) plaques and intracellular hyperphosphorylated tau-containing neurofibrillary tangles (NFTs) in the brain are the hallmarks of AD. They are also thought to be the underlying cause of inflammation, neurodegeneration, brain atrophy, and cognitive impairments that accompany AD. The discovery of APP, PS1, and PS2 mutations that increase Aβ production in families with early onset familial AD led to the development of numerous transgenic rodent models of AD. These models have provided new insight into the role of Aβ in AD; however, they do not fully replicate AD pathology in patients. Familial AD patients with mutations that elevate the production of Aβ represent only a small fraction of dementia patients. In contrast, those with late-onset sporadic AD constitute the majority of cases. This observation, along with the failure of previous clinical trials targeting Aβ or Tau and the modest success of recent trials using Aβ monoclonal antibodies, has led to a reappraisal of the view that Aβ accumulation is the sole factor in the pathogenesis of AD. More recent studies have established that cerebral vascular dysfunction is one of the earliest changes seen in AD, and 67% of the candidate genes linked to AD are expressed in the cerebral vasculature. Thus, there is an increasing appreciation of the vascular contribution to AD, and the National Institute on Aging (NIA) and the Alzheimer's Disease Foundation recently prioritized it as a focused research area. This review summarizes the strengths and limitations of the most commonly used transgenic AD animal models and current views about the contribution of Aβ accumulation versus cerebrovascular dysfunction in the pathogenesis of AD.
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Affiliation(s)
- Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Fan Fan
- Department of Physiology, Augusta University, Augusta, GA 30912, USA
| | - Jane J. Border
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Richard J. Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA
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Penn C, Katnik C, Cuevas J, Mohapatra SS, Mohapatra S. Multispectral optoacoustic tomography (MSOT): Monitoring neurovascular changes in a mouse repetitive traumatic brain injury model. J Neurosci Methods 2023; 393:109876. [PMID: 37150303 PMCID: PMC10388337 DOI: 10.1016/j.jneumeth.2023.109876] [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: 03/21/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 05/09/2023]
Abstract
BACKGROUND Evidence suggests that mild TBI injuries, which comprise > 75% of all TBIs, can cause chronic post-concussive symptoms, especially when experienced repetitively (rTBI). rTBI is a major cause of cognitive deficit in athletes and military personnel and is associated with neurovascular changes. Current methods to monitor neurovascular changes in detail are prohibitively expensive and invasive for patients with mild injuries. NEW METHOD We evaluated the potential of multispectral optoacoustic tomography (MSOT) to monitor neurovascular changes and assess therapeutic strategies in a mouse model of rTBI. Mice were subjected to rTBI or sham via controlled cortical impact and administered pioglitazone (PG) or vehicle. Oxygenated and deoxygenated hemoglobin were monitored using MSOT. Indocyanine green clearance was imaged via MSOT to evaluate blood-brain-barrier (BBB) integrity. RESULTS Mice subjected to rTBI show a transient increase in oxygenated/total hemoglobin ratio which can be mitigated by PG administration. rTBI mice also show BBB disruption shortly after injury and reduction of oxygenated/total hemoglobin in the chronic stage, neither of which were affected by PG intervention. COMPARISON WITH EXISTING METHODS MSOT imaging has the potential as a noninvasive in vivo imaging method to monitor neurovascular changes and assess therapeutics in mouse models of rTBI. In comparison to standard methods of tracking inflammation and BBB disruption, MSOT can be used multiple times throughout the course of injury without the need for surgery. Thus, MSOT is especially useful in research of rTBI models for screening therapeutics, and with further technological improvements may be extended for use in rTBI patients.
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Affiliation(s)
- Courtney Penn
- James A. Haley Veterans Hospital, 13000 Bruce B Downs Blvd, Tampa, FL 33612, USA; Department of Molecular Medicine, University of South Florida Morsani College of Medicine, 12901 Bruce B Downs Blvd., Tampa, FL 33612, USA
| | - Chris Katnik
- Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, 12901 Bruce B Downs Blvd., Tampa, FL 33612, USA
| | - Javier Cuevas
- Department of Molecular Pharmacology and Physiology, University of South Florida Morsani College of Medicine, 12901 Bruce B Downs Blvd., Tampa, FL 33612, USA
| | - Shyam S Mohapatra
- James A. Haley Veterans Hospital, 13000 Bruce B Downs Blvd, Tampa, FL 33612, USA; Department of Internal Medicine, University of South Florida Morsani College of Medicine, 12901 Bruce B Downs Blvd., Tampa, FL 33612, USA
| | - Subhra Mohapatra
- James A. Haley Veterans Hospital, 13000 Bruce B Downs Blvd, Tampa, FL 33612, USA; Department of Molecular Medicine, University of South Florida Morsani College of Medicine, 12901 Bruce B Downs Blvd., Tampa, FL 33612, USA.
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Obenaus A, Rodriguez-Grande B, Lee JB, Dubois CJ, Fournier ML, Cador M, Caille S, Badaut J. A single mild juvenile TBI in male mice leads to regional brain tissue abnormalities at 12 months of age that correlate with cognitive impairment at the middle age. Acta Neuropathol Commun 2023; 11:32. [PMID: 36859364 PMCID: PMC9976423 DOI: 10.1186/s40478-023-01515-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 01/12/2023] [Indexed: 03/03/2023] Open
Abstract
Traumatic brain injury (TBI) has the highest incidence amongst the pediatric population and its mild severity represents the most frequent cases. Moderate and severe injuries as well as repetitive mild TBI result in lasting morbidity. However, whether a single mild TBI sustained during childhood can produce long-lasting modifications within the brain is still debated. We aimed to assess the consequences of a single juvenile mild TBI (jmTBI) at 12 months post-injury in a mouse model. Non-invasive diffusion tensor imaging (DTI) revealed significant microstructural alterations in the hippocampus and the in the substantia innominata/nucleus basalis (SI/NB), structures known to be involved in spatial learning and memory. DTI changes paralled neuronal loss, increased astrocytic AQP4 and microglial activation in the hippocampus. In contrast, decreased astrocytic AQP4 expression and microglia activation were observed in SI/NB. Spatial learning and memory were impaired and correlated with alterations in DTI-derived derived fractional ansiotropy (FA) and axial diffusivity (AD). This study found that a single juvenile mild TBI leads to significant region-specific DTI microstructural alterations, distant from the site of impact, that correlated with cognitive discriminative novel object testing and spatial memory impairments at 12 months after a single concussive injury. Our findings suggest that exposure to jmTBI leads to a chronic abnormality, which confirms the need for continued monitoring of symptoms and the development of long-term treatment strategies to intervene in children with concussions.
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Affiliation(s)
- Andre Obenaus
- Department of Pediatrics, University of California, Irvine, CA, USA
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | | | - Jeong Bin Lee
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Christophe J Dubois
- CNRS UMR 5536 RMSB, University of Bordeaux, 146 Rue Léo Saignat, 33076, Bordeaux Cedex, France
| | | | - Martine Cador
- CNRS, EPHE, INCIA UMR5287, University of Bordeaux, F33000, Bordeaux, France
| | - Stéphanie Caille
- CNRS, EPHE, INCIA UMR5287, University of Bordeaux, F33000, Bordeaux, France
| | - Jerome Badaut
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA.
- CNRS, EPHE, INCIA UMR5287, University of Bordeaux, F33000, Bordeaux, France.
- CNRS UMR 5536 RMSB, University of Bordeaux, 146 Rue Léo Saignat, 33076, Bordeaux Cedex, France.
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Oh ES, Freeberg KA, Steele CN, Wang W, Farmer‐Bailey H, Coppock ME, Seals DR, Chonchol M, Rossman MJ, Craighead DH, Nowak KL. Cerebrovascular pulsatility index is higher in chronic kidney disease. Physiol Rep 2023; 11:e15561. [PMID: 36636757 PMCID: PMC9837424 DOI: 10.14814/phy2.15561] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 12/16/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023] Open
Abstract
Patients with chronic kidney disease (CKD) are more likely to die of cardiovascular diseases, including cerebrovascular disease, than to progress to end-stage kidney disease. Cerebrovascular dysfunction, characterized by reduced cerebrovascular reactivity, cerebral hypoperfusion, and increased pulsatile flow within the brain, precedes the onset of dementia and is linked to cognitive dysfunction. However, whether impaired cerebrovascular function is present in non-dialysis dependent CKD is largely unknown. Using transcranial Doppler, we compared middle cerebral artery (MCA) blood velocity response to hypercapnia (normalized for blood pressure and end-tidal CO2 ; a measure of cerebrovascular reactivity) and MCA pulsatility index (PI; a measure of cerebrovascular stiffness) in patients with stage 3-4 CKD vs. age-matched healthy controls. We also administered the NIH cognitive toolbox (cognitive function), measured carotid-femoral pulse-wave velocity (PWV; aortic stiffness), and assessed ex vivo nitric oxide (NO) and reactive oxygen species (ROS) production from human brain endothelial cells incubated with serum obtained from study participants. MCA PI was higher in patients with CKD vs. controls; however, normalized MCA blood velocity response to hypercapnia did not differ between groups. Similar results were observed in a validation cohort of midlife and older adults divided by the median estimated glomerular filtration rate (eGFR). MCA PI was associated with greater large-elastic artery stiffness (carotid-femoral PWV), worse executive function (trails B time), lower eGFR, and higher ex vivo ROS production. These data suggest that impaired kidney function is associated with greater cerebrovascular stiffness, which may contribute to the known increased risk for cognitive impairment in patients with CKD.
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Affiliation(s)
- Ester S. Oh
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Kaitlin A. Freeberg
- Department of Integrative PhysiologyUniversity of Colorado BoulderBoulderColoradoUSA
| | - Cortney N. Steele
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Wei Wang
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Heather Farmer‐Bailey
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - McKinley E. Coppock
- Department of Integrative PhysiologyUniversity of Colorado BoulderBoulderColoradoUSA
| | - Douglas R. Seals
- Department of Integrative PhysiologyUniversity of Colorado BoulderBoulderColoradoUSA
| | - Michel Chonchol
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Matthew J. Rossman
- Department of Integrative PhysiologyUniversity of Colorado BoulderBoulderColoradoUSA
| | - Daniel H. Craighead
- Department of Integrative PhysiologyUniversity of Colorado BoulderBoulderColoradoUSA
| | - Kristen L. Nowak
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
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Morisset C, Dizeux A, Larrat B, Selingue E, Boutin H, Picaud S, Sahel JA, Ialy-Radio N, Pezet S, Tanter M, Deffieux T. Retinal functional ultrasound imaging (rfUS) for assessing neurovascular alterations: a pilot study on a rat model of dementia. Sci Rep 2022; 12:19515. [PMID: 36376408 PMCID: PMC9663720 DOI: 10.1038/s41598-022-23366-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 10/31/2022] [Indexed: 11/16/2022] Open
Abstract
Fifty million people worldwide are affected by dementia, a heterogeneous neurodegenerative condition encompassing diseases such as Alzheimer's, vascular dementia, and Parkinson's. For them, cognitive decline is often the first marker of the pathology after irreversible brain damage has already occurred. Researchers now believe that structural and functional alterations of the brain vasculature could be early precursors of the diseases and are looking at how functional imaging could provide an early diagnosis years before irreversible clinical symptoms. In this preclinical pilot study, we proposed using functional ultrasound (fUS) on the retina to assess neurovascular alterations non-invasively, bypassing the skull limitation. We demonstrated for the first time the use of functional ultrasound in the retina and applied it to characterize the retinal hemodynamic response function in vivo in rats following a visual stimulus. We then demonstrated that retinal fUS could measure robust neurovascular coupling alterations between wild-type rats and TgF344-AD rat models of Alzheimer's disease. We observed an average relative increase in blood volume of 21% in the WT versus 37% for the TG group (p = 0.019). As a portable, non-invasive and inexpensive technique, rfUS is a promising functional screening tool in clinics for dementia years before symptoms.
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Affiliation(s)
- Clementine Morisset
- grid.440907.e0000 0004 1784 3645Institute Physics for Medicine Paris, INSERM U1273, ESPCI PSL Paris, CNRS UMR 8631, PSL Research University, Paris, France
| | - Alexandre Dizeux
- grid.440907.e0000 0004 1784 3645Institute Physics for Medicine Paris, INSERM U1273, ESPCI PSL Paris, CNRS UMR 8631, PSL Research University, Paris, France
| | - Benoit Larrat
- grid.457334.20000 0001 0667 2738NeuroSpin, Institut Des Sciences du Vivant Frédéric Joliot, Commissariat À L’Energie Atomique Et Aux Energies Alternatives (CEA), CNRS, Université Paris-Saclay, 91191 Gif-Sur-Yvette, France
| | - Erwan Selingue
- grid.457334.20000 0001 0667 2738NeuroSpin, Institut Des Sciences du Vivant Frédéric Joliot, Commissariat À L’Energie Atomique Et Aux Energies Alternatives (CEA), CNRS, Université Paris-Saclay, 91191 Gif-Sur-Yvette, France
| | - Herve Boutin
- grid.5379.80000000121662407Faculty of Biology, Medicine and Health, School of Biological Sciences Division of Neuroscience and Experimental Psychology, University of Manchester, Manchester, M13 9PL UK ,grid.5379.80000000121662407Wolfson Molecular Imaging Centre, University of Manchester, 27 Palatine Road, Manchester, M20 3LJ UK ,grid.462482.e0000 0004 0417 0074Geoffrey Jefferson Brain Research Centre, Manchester Academic Health Science Centre, Northern Care Alliance and University of Manchester, Manchester, UK
| | - Serge Picaud
- grid.418241.a0000 0000 9373 1902Institut de La Vision, Sorbonne Université, INSERM, CNRS, 17 Rue Moreau, 75012 Paris, France
| | - Jose-Alain Sahel
- grid.418241.a0000 0000 9373 1902Institut de La Vision, Sorbonne Université, INSERM, CNRS, 17 Rue Moreau, 75012 Paris, France ,grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213 USA ,grid.417888.a0000 0001 2177 525XDepartment of Ophthalmology and Vitreo-Retinal Diseases, Fondation Ophtalmologique Rothschild, 75019 Paris, France
| | - Nathalie Ialy-Radio
- grid.440907.e0000 0004 1784 3645Institute Physics for Medicine Paris, INSERM U1273, ESPCI PSL Paris, CNRS UMR 8631, PSL Research University, Paris, France
| | - Sophie Pezet
- grid.440907.e0000 0004 1784 3645Institute Physics for Medicine Paris, INSERM U1273, ESPCI PSL Paris, CNRS UMR 8631, PSL Research University, Paris, France
| | - Mickael Tanter
- grid.440907.e0000 0004 1784 3645Institute Physics for Medicine Paris, INSERM U1273, ESPCI PSL Paris, CNRS UMR 8631, PSL Research University, Paris, France
| | - Thomas Deffieux
- grid.440907.e0000 0004 1784 3645Institute Physics for Medicine Paris, INSERM U1273, ESPCI PSL Paris, CNRS UMR 8631, PSL Research University, Paris, France
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7
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Marmarelis VZ, Shin DC, Zhang R. The Dynamic Relationship Between Cortical Oxygenation and End-Tidal CO 2 Transient Changes Is Impaired in Mild Cognitive Impairment Patients. Front Physiol 2021; 12:772456. [PMID: 34955886 PMCID: PMC8695976 DOI: 10.3389/fphys.2021.772456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 11/19/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Recent studies have utilized data-based dynamic modeling to establish strong association between dysregulation of cerebral perfusion and Mild Cognitive Impairment (MCI), expressed in terms of impaired CO2 dynamic vasomotor reactivity in the cerebral vasculature. This raises the question of whether this is due to dysregulation of central mechanisms (baroreflex and chemoreflex) or mechanisms of cortical tissue oxygenation (CTO) in MCI patients. We seek to answer this question using data-based input-output predictive dynamic models. Objective: To use subject-specific data-based multivariate input-output dynamic models to quantify the effects of systemic hemodynamic and blood CO2 changes upon CTO and to examine possible differences in CTO regulation in MCI patients versus age-matched controls, after the dynamic effects of central regulatory mechanisms have been accounted for by using cerebral flow measurements as another input. Methods: The employed model-based approach utilized the general dynamic modeling methodology of Laguerre expansions of kernels to analyze spontaneous time-series data in order to quantify the dynamic effects upon CTO (an index of relative capillary hemoglobin saturation distribution measured via near-infrared spectroscopy) of contemporaneous changes in end-tidal CO2 (proxy for arterial CO2), arterial blood pressure and cerebral blood flow velocity in the middle cerebral arteries (measured via transcranial Doppler). Model-based indices (physio-markers) were computed for these distinct dynamic relationships. Results: The obtained model-based indices revealed significant statistical differences of CO2 dynamic vasomotor reactivity in cortical tissue, combined with "perfusivity" that quantifies the dynamic relationship between flow velocity in cerebral arteries and CTO in MCI patients versus age-matched controls (p = 0.006). Significant difference between MCI patients and age-matched controls was also found in the respective model-prediction accuracy (p = 0.0001). Combination of these model-based indices via the Fisher Discriminant achieved even smaller p-value (p = 5 × 10-5) when comparing MCI patients with controls. The differences in dynamics of CTO in MCI patients are in lower frequencies (<0.05 Hz), suggesting impairment in endocrine/metabolic (rather than neural) mechanisms. Conclusion: The presented model-based approach elucidates the multivariate dynamic connectivity in the regulation of cerebral perfusion and yields model-based indices that may serve as physio-markers of possible dysregulation of CTO during transient CO2 changes in MCI patients.
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Affiliation(s)
- Vasilis Z. Marmarelis
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA, United States
| | - Dae C. Shin
- Biomedical Engineering Department, University of Southern California, Los Angeles, CA, United States
| | - Rong Zhang
- Institute for Exercise and Environmental Medicine, UT Southwestern Medical Center, Dallas, TX, United States
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Seker FB, Fan Z, Gesierich B, Gaubert M, Sienel RI, Plesnila N. Neurovascular Reactivity in the Aging Mouse Brain Assessed by Laser Speckle Contrast Imaging and 2-Photon Microscopy: Quantification by an Investigator-Independent Analysis Tool. Front Neurol 2021; 12:745770. [PMID: 34858312 PMCID: PMC8631776 DOI: 10.3389/fneur.2021.745770] [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: 07/22/2021] [Accepted: 10/08/2021] [Indexed: 11/13/2022] Open
Abstract
The brain has a high energy demand but little to no energy stores. Therefore, proper brain function relies on the delivery of glucose and oxygen by the cerebral vasculature. The regulation of cerebral blood flow (CBF) occurs at the level of the cerebral capillaries and is driven by a fast and efficient crosstalk between neurons and vessels, a process termed neurovascular coupling (NVC). Experimentally NVC is mainly triggered by sensory stimulation and assessed by measuring either CBF by laser Doppler fluxmetry, laser speckle contrast imaging (LSCI), intrinsic optical imaging, BOLD fMRI, near infrared spectroscopy (NIRS) or functional ultrasound imaging (fUS). Since these techniques have relatively low spatial resolution, diameters of cerebral vessels are mainly assessed by 2-photon microscopy (2-PM). Results of studies on NVC rely on stable animal physiology, high-quality data acquisition, and unbiased data analysis, criteria, which are not easy to achieve. In the current study, we assessed NVC using two different imaging modalities, i.e., LSCI and 2-PM, and analyzed our data using an investigator-independent Matlab-based analysis tool, after manually defining the area of analysis in LSCI and vessels to measure in 2-PM. By investigating NVC in 6–8 weeks, 1-, and 2-year-old mice, we found that NVC was maximal in 1-year old mice and was significantly reduced in aged mice. These findings suggest that NVC is differently affected during the aging process. Most interestingly, specifically pial arterioles, seem to be distinctly affected by the aging. The main finding of our study is that the automated analysis tool works very efficiently in terms of time and accuracy. In fact, the tool reduces the analysis time of one animal from approximately 23 h to about 2 s while basically making no mistakes. In summary, we developed an experimental workflow, which allows us to reliably measure NVC with high spatial and temporal resolution in young and aged mice and to analyze these data in an investigator-independent manner.
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Affiliation(s)
- Fatma Burcu Seker
- Institute for Stroke and Dementia Research, Munich University Hospital and University of Munich, Munich, Germany
| | - Ziyu Fan
- Institute for Stroke and Dementia Research, Munich University Hospital and University of Munich, Munich, Germany
| | - Benno Gesierich
- Institute for Stroke and Dementia Research, Munich University Hospital and University of Munich, Munich, Germany
| | - Malo Gaubert
- Institute for Stroke and Dementia Research, Munich University Hospital and University of Munich, Munich, Germany
| | - Rebecca Isabella Sienel
- Institute for Stroke and Dementia Research, Munich University Hospital and University of Munich, Munich, Germany
| | - Nikolaus Plesnila
- Institute for Stroke and Dementia Research, Munich University Hospital and University of Munich, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
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9
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Lourenço CF, Laranjinha J. Nitric Oxide Pathways in Neurovascular Coupling Under Normal and Stress Conditions in the Brain: Strategies to Rescue Aberrant Coupling and Improve Cerebral Blood Flow. Front Physiol 2021; 12:729201. [PMID: 34744769 PMCID: PMC8569710 DOI: 10.3389/fphys.2021.729201] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 09/20/2021] [Indexed: 01/04/2023] Open
Abstract
The brain has impressive energy requirements and paradoxically, very limited energy reserves, implying its huge dependency on continuous blood supply. Aditionally, cerebral blood flow must be dynamically regulated to the areas of increased neuronal activity and thus, of increased metabolic demands. The coupling between neuronal activity and cerebral blood flow (CBF) is supported by a mechanism called neurovascular coupling (NVC). Among the several vasoactive molecules released by glutamatergic activation, nitric oxide (•NO) is recognized to be a key player in the process and essential for the development of the neurovascular response. Classically, •NO is produced in neurons upon the activation of the glutamatergic N-methyl-D-aspartate (NMDA) receptor by the neuronal isoform of nitric oxide synthase and promotes vasodilation by activating soluble guanylate cyclase in the smooth muscle cells of the adjacent arterioles. This pathway is part of a more complex network in which other molecular and cellular intervenients, as well as other sources of •NO, are involved. The elucidation of these interacting mechanisms is fundamental in understanding how the brain manages its energy requirements and how the failure of this process translates into neuronal dysfunction. Here, we aimed to provide an integrated and updated perspective of the role of •NO in the NVC, incorporating the most recent evidence that reinforces its central role in the process from both viewpoints, as a physiological mediator and a pathological stressor. First, we described the glutamate-NMDA receptor-nNOS axis as a central pathway in NVC, then we reviewed the link between the derailment of the NVC and neuronal dysfunction associated with neurodegeneration (with a focus on Alzheimer's disease). We further discussed the role of oxidative stress in the NVC dysfunction, specifically by decreasing the •NO bioavailability and diverting its bioactivity toward cytotoxicity. Finally, we highlighted some strategies targeting the rescue or maintenance of •NO bioavailability that could be explored to mitigate the NVC dysfunction associated with neurodegenerative conditions. In line with this, the potential modulatory effects of dietary nitrate and polyphenols on •NO-dependent NVC, in association with physical exercise, may be used as effective non-pharmacological strategies to promote the •NO bioavailability and to manage NVC dysfunction in neuropathological conditions.
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Affiliation(s)
- Cátia F Lourenço
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - João Laranjinha
- Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
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10
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Ouellette J, Lacoste B. From Neurodevelopmental to Neurodegenerative Disorders: The Vascular Continuum. Front Aging Neurosci 2021; 13:749026. [PMID: 34744690 PMCID: PMC8570842 DOI: 10.3389/fnagi.2021.749026] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/13/2021] [Indexed: 12/12/2022] Open
Abstract
Structural and functional integrity of the cerebral vasculature ensures proper brain development and function, as well as healthy aging. The inability of the brain to store energy makes it exceptionally dependent on an adequate supply of oxygen and nutrients from the blood stream for matching colossal demands of neural and glial cells. Key vascular features including a dense vasculature, a tightly controlled environment, and the regulation of cerebral blood flow (CBF) all take part in brain health throughout life. As such, healthy brain development and aging are both ensured by the anatomical and functional interaction between the vascular and nervous systems that are established during brain development and maintained throughout the lifespan. During critical periods of brain development, vascular networks remodel until they can actively respond to increases in neural activity through neurovascular coupling, which makes the brain particularly vulnerable to neurovascular alterations. The brain vasculature has been strongly associated with the onset and/or progression of conditions associated with aging, and more recently with neurodevelopmental disorders. Our understanding of cerebrovascular contributions to neurological disorders is rapidly evolving, and increasing evidence shows that deficits in angiogenesis, CBF and the blood-brain barrier (BBB) are causally linked to cognitive impairment. Moreover, it is of utmost curiosity that although neurodevelopmental and neurodegenerative disorders express different clinical features at different stages of life, they share similar vascular abnormalities. In this review, we present an overview of vascular dysfunctions associated with neurodevelopmental (autism spectrum disorders, schizophrenia, Down Syndrome) and neurodegenerative (multiple sclerosis, Huntington's, Parkinson's, and Alzheimer's diseases) disorders, with a focus on impairments in angiogenesis, CBF and the BBB. Finally, we discuss the impact of early vascular impairments on the expression of neurodegenerative diseases.
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Affiliation(s)
- Julie Ouellette
- Ottawa Hospital Research Institute, Neuroscience Program, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Baptiste Lacoste
- Ottawa Hospital Research Institute, Neuroscience Program, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON, Canada
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11
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Claassen JAHR, Thijssen DHJ, Panerai RB, Faraci FM. Regulation of cerebral blood flow in humans: physiology and clinical implications of autoregulation. Physiol Rev 2021; 101:1487-1559. [PMID: 33769101 PMCID: PMC8576366 DOI: 10.1152/physrev.00022.2020] [Citation(s) in RCA: 289] [Impact Index Per Article: 96.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Brain function critically depends on a close matching between metabolic demands, appropriate delivery of oxygen and nutrients, and removal of cellular waste. This matching requires continuous regulation of cerebral blood flow (CBF), which can be categorized into four broad topics: 1) autoregulation, which describes the response of the cerebrovasculature to changes in perfusion pressure; 2) vascular reactivity to vasoactive stimuli [including carbon dioxide (CO2)]; 3) neurovascular coupling (NVC), i.e., the CBF response to local changes in neural activity (often standardized cognitive stimuli in humans); and 4) endothelium-dependent responses. This review focuses primarily on autoregulation and its clinical implications. To place autoregulation in a more precise context, and to better understand integrated approaches in the cerebral circulation, we also briefly address reactivity to CO2 and NVC. In addition to our focus on effects of perfusion pressure (or blood pressure), we describe the impact of select stimuli on regulation of CBF (i.e., arterial blood gases, cerebral metabolism, neural mechanisms, and specific vascular cells), the interrelationships between these stimuli, and implications for regulation of CBF at the level of large arteries and the microcirculation. We review clinical implications of autoregulation in aging, hypertension, stroke, mild cognitive impairment, anesthesia, and dementias. Finally, we discuss autoregulation in the context of common daily physiological challenges, including changes in posture (e.g., orthostatic hypotension, syncope) and physical activity.
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Affiliation(s)
- Jurgen A H R Claassen
- Department of Geriatrics, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, The Netherlands
| | - Dick H J Thijssen
- Department of Physiology, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- >National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Frank M Faraci
- Departments of Internal Medicine, Neuroscience, and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
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12
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Targeting Endothelin in Alzheimer's Disease: A Promising Therapeutic Approach. BIOMED RESEARCH INTERNATIONAL 2021; 2021:7396580. [PMID: 34532504 PMCID: PMC8440097 DOI: 10.1155/2021/7396580] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 08/07/2021] [Indexed: 11/18/2022]
Abstract
Endothelin is a chemical mediator that helps in maintaining balance within the blood-brain barrier by regulating the levels of toxicants and molecules which pass through the brain, suggesting that a rise in its production determines Alzheimer's disease. The inequity in the amyloid β occurs due to a problem in its clearance from the brain initiating the production of reactive oxygen species and superoxide that activates a cascade wherein the release of inflammatory mediators and various enzymes like endothelin-converting enzymes take place. Furthermore, the cascade increases the levels of endothelin in the brain from endothelial cells. Endothelin levels are upregulated, which can be regulated by modulating the action of endothelin-converting enzymes and endothelin receptors. Hence, endothelin paves a pathway in the treatment of Alzheimer's disease. In this article, we have covered various mechanisms and preclinical studies that support and direct endothelin involvement in the progression of Alzheimer's disease by using various search tools such as PubMed, Science Direct, and Medline. Conclusive outcome data were extracted that all together defy contrivance pathways, potential drugs, endothelin receptors, and endothelin enzymes in our article giving profound importance to target endothelin for prevention and treatment of Alzheimer's disease.
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13
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Burma JS, Wassmuth RM, Kennedy CM, Miutz LN, Newel KT, Carere J, Smirl JD. Does task complexity impact the neurovascular coupling response similarly between males and females? Physiol Rep 2021; 9:e15020. [PMID: 34514743 PMCID: PMC8436054 DOI: 10.14814/phy2.15020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 08/10/2021] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND While previous studies have demonstrated a complex visual scene search elicits a robust neurovascular coupling (NVC) response, it is unknown how the duration of visual stimuli presentation influences NVC metrics. This study examined how stimuli duration, in addition to biological sex and self-reported engagement impact NVC responses. METHODS Participants (n = 20, female = 10) completed four visual paradigms. Three involved simple visual shapes presented at 0.5-, 2-, and 4-s intervals in randomized orders. The fourth paradigm was a complex visual scene search ("Where's Waldo?"). Participants completed eight cycles of 20-s eyes-closed followed by 40-s eyes-open. Transcranial Doppler ultrasound indexed posterior and middle cerebral artery velocities (PCA and MCA). Participants self-reported their engagement following each task (1 [minimal] to 10 [maximal]). RESULTS The "Where's Waldo?" task evoked greater PCA percent increase (all p < 0.001) and area under the curve during the first 30-s of the task (all p < 0.001) compared to simple shapes. Females displayed greater absolute baseline and peak PCA and MCA velocities across all tasks (all p < 0.002). Subjective engagement displayed moderate correlation levels with PCA percent increase (Spearman ρ = 0.58) and area under the curve (Spearman ρ = 0.60) metrics in males, whereas these were weak for females (Spearman ρ = 0.43 and ρ = 0.38, respectively). CONCLUSIONS The complex visual paradigm "Where's Waldo?" greatly augmented the signal-to-noise ratio within the PCA aspects of the NVC response compared to simple shapes. While both sexes had similar NVC responses, task engagement was more related to NVC metrics in males compared to females. Therefore, future NVC investigations should consider task engagement when designing studies.
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Nyul-Toth A, DelFavero J, Mukli P, Tarantini A, Ungvari A, Yabluchanskiy A, Csiszar A, Ungvari Z, Tarantini S. Early manifestation of gait alterations in the Tg2576 mouse model of Alzheimer's disease. GeroScience 2021; 43:1947-1957. [PMID: 34160781 PMCID: PMC8492885 DOI: 10.1007/s11357-021-00401-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/07/2021] [Indexed: 01/04/2023] Open
Abstract
There is strong clinical evidence that multifaceted gait abnormalities may be manifested at early stages of Alzheimer's disease (AD), are related to cognitive decline, and can be used as an early biomarker to identify patients at risk of progressing to full-blown dementia. Despite their importance, gait abnormalities have not been investigated in mouse models of AD, which replicate important aspects of the human disease. The Tg2576 is frequently used in AD research to test therapeutic interventions targeting cellular mechanisms contributing to the genesis of AD. This transgenic mouse strain overexpresses a mutant form of the 695 amino acid isoform of human amyloid precursor protein with K670N and M671L mutations (APPK670/671L) linked to early-onset familial AD. Tg2576 mice exhibit impaired cognitive functions and increased cortical and hippocampal soluble β-amyloid levels starting from 5 months of age and increased insoluble β-amyloid levels and amyloid plaques that resemble senile plaques associated with human AD by 13 months of age. To demonstrate early manifestations of gait dysfunction in this relevant preclinical model, we characterized gait and motor performance in 10-month-old Tg2576 mice and age-matched littermate controls using the semi-automated, highly sensitive, Catwalk XT system. We found that Tg2576 mice at the pre-plaque stage exhibited significantly altered duty cycle and step patterns and decreased stride length and stride time. Base-of-support, stride time variability, stride length variability, cadence, phase dispersions and gait symmetry indices were unaltered. The presence of measurable early gait abnormalities during the pre-plaque stages of AD in this relevant preclinical mouse model has direct translational relevance and supports the view that longitudinal monitoring of gait performance could be used in addition to behavioral testing to evaluate progression of the disease and to assess treatment efficacy.
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Affiliation(s)
- Adam Nyul-Toth
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 N. E. 10th Street - BRC 1303, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
| | - Jordan DelFavero
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 N. E. 10th Street - BRC 1303, Oklahoma City, OK, 73104, USA
| | - Peter Mukli
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 N. E. 10th Street - BRC 1303, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Amber Tarantini
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 N. E. 10th Street - BRC 1303, Oklahoma City, OK, 73104, USA
| | - Anna Ungvari
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 N. E. 10th Street - BRC 1303, Oklahoma City, OK, 73104, USA
| | - Andriy Yabluchanskiy
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 N. E. 10th Street - BRC 1303, Oklahoma City, OK, 73104, USA
| | - Anna Csiszar
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 N. E. 10th Street - BRC 1303, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Translational Medicine, Semmelweis University, Budapest, Hungary
| | - Zoltan Ungvari
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 N. E. 10th Street - BRC 1303, Oklahoma City, OK, 73104, USA.
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary.
| | - Stefano Tarantini
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 N. E. 10th Street - BRC 1303, Oklahoma City, OK, 73104, USA.
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary.
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15
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Bracko O, Cruz Hernández JC, Park L, Nishimura N, Schaffer CB. Causes and consequences of baseline cerebral blood flow reductions in Alzheimer's disease. J Cereb Blood Flow Metab 2021; 41:1501-1516. [PMID: 33444096 PMCID: PMC8221770 DOI: 10.1177/0271678x20982383] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/27/2020] [Accepted: 11/16/2020] [Indexed: 12/23/2022]
Abstract
Reductions of baseline cerebral blood flow (CBF) of ∼10-20% are a common symptom of Alzheimer's disease (AD) that appear early in disease progression and correlate with the severity of cognitive impairment. These CBF deficits are replicated in mouse models of AD and recent work shows that increasing baseline CBF can rapidly improve the performance of AD mice on short term memory tasks. Despite the potential role these data suggest for CBF reductions in causing cognitive symptoms and contributing to brain pathology in AD, there remains a poor understanding of the molecular and cellular mechanisms causing them. This review compiles data on CBF reductions and on the correlation of AD-related CBF deficits with disease comorbidities (e.g. cardiovascular and genetic risk factors) and outcomes (e.g. cognitive performance and brain pathology) from studies in both patients and mouse models, and discusses several potential mechanisms proposed to contribute to CBF reductions, based primarily on work in AD mouse models. Future research aimed at improving our understanding of the importance of and interplay between different mechanisms for CBF reduction, as well as at determining the role these mechanisms play in AD patients could guide the development of future therapies that target CBF reductions in AD.
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Affiliation(s)
- Oliver Bracko
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Jean C Cruz Hernández
- Center for Systems Biology and Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Laibaik Park
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY, USA
| | - Nozomi Nishimura
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Chris B Schaffer
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA
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16
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Turner DA. Contrasting Metabolic Insufficiency in Aging and Dementia. Aging Dis 2021; 12:1081-1096. [PMID: 34221551 PMCID: PMC8219502 DOI: 10.14336/ad.2021.0104] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 01/04/2021] [Indexed: 12/14/2022] Open
Abstract
Metabolic insufficiency and neuronal dysfunction occur in normal aging but is exaggerated in dementia and Alzheimer's disease (AD). Metabolic insufficiency includes factors important for both substrate supply and utilization in the brain. Metabolic insufficiency occurs through a number of serial mechanisms, particularly changes in cerebrovascular supply through blood vessel abnormalities (ie, small and large vessel vasculopathy, stroke), alterations in neurovascular coupling providing dynamic blood flow supply in relation to neuronal demand, abnormalities in blood brain barrier including decreased glucose and amino acid transport, altered glymphatic flow in terms of substrate supply across the extracellular space to cells and drainage into CSF of metabolites, impaired transport into cells, and abnormal intracellular metabolism with more reliance on glycolysis and less on mitochondrial function. Recent studies have confirmed abnormal neurovascular coupling in a mouse model of AD in response to metabolic challenges, but the supply chain from the vascular system into neurons is disrupted much earlier in dementia than in equivalently aged individuals, contributing to the progressive neuronal degeneration and cognitive dysfunction associated with dementia. We discuss several metabolic treatment approaches, but these depend on characterizing patients as to who would benefit the most. Surrogate biomarkers of metabolism are being developed to include dynamic estimates of neuronal demand, sufficiency of neurovascular coupling, and glymphatic flow to supplement traditional static measurements. These surrogate biomarkers could be used to gauge efficacy of metabolic treatments in slowing down or modifying dementia time course.
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Affiliation(s)
- Dennis A Turner
- Neurosurgery, Neurobiology, and Biomedical Engineering, Duke University Medical Center, Durham, NC 27710, USA.
- Research and Surgery Services, Durham Veterans Affairs Medical Center, Durham, NC 27705, USA.
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17
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Nizari S, Wells JA, Carare RO, Romero IA, Hawkes CA. Loss of cholinergic innervation differentially affects eNOS-mediated blood flow, drainage of Aβ and cerebral amyloid angiopathy in the cortex and hippocampus of adult mice. Acta Neuropathol Commun 2021; 9:12. [PMID: 33413694 PMCID: PMC7791879 DOI: 10.1186/s40478-020-01108-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/15/2020] [Indexed: 11/18/2022] Open
Abstract
Vascular dysregulation and cholinergic basal forebrain degeneration are both early pathological events in the development of Alzheimer’s disease (AD). Acetylcholine contributes to localised arterial dilatation and increased cerebral blood flow (CBF) during neurovascular coupling via activation of endothelial nitric oxide synthase (eNOS). Decreased vascular reactivity is suggested to contribute to impaired clearance of β-amyloid (Aβ) along intramural periarterial drainage (IPAD) pathways of the brain, leading to the development of cerebral amyloid angiopathy (CAA). However, the possible relationship between loss of cholinergic innervation, impaired vasoreactivity and reduced clearance of Aβ from the brain has not been previously investigated. In the present study, intracerebroventricular administration of mu-saporin resulted in significant death of cholinergic neurons and fibres in the medial septum, cortex and hippocampus of C57BL/6 mice. Arterial spin labelling MRI revealed a loss of CBF response to stimulation of eNOS by the Rho-kinase inhibitor fasudil hydrochloride in the cortex of denervated mice. By contrast, the hippocampus remained responsive to drug treatment, in association with altered eNOS expression. Fasudil hydrochloride significantly increased IPAD in the hippocampus of both control and saporin-treated mice, while increased clearance from the cortex was only observed in control animals. Administration of mu-saporin in the TetOAPPSweInd mouse model of AD was associated with a significant and selective increase in Aβ40-positive CAA. These findings support the importance of the interrelationship between cholinergic innervation and vascular function in the aetiology and/or progression of CAA and suggest that combined eNOS/cholinergic therapies may improve the efficiency of Aβ removal from the brain and reduce its deposition as CAA.
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Hariharan A, Weir N, Robertson C, He L, Betsholtz C, Longden TA. The Ion Channel and GPCR Toolkit of Brain Capillary Pericytes. Front Cell Neurosci 2020; 14:601324. [PMID: 33390906 PMCID: PMC7775489 DOI: 10.3389/fncel.2020.601324] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022] Open
Abstract
Brain pericytes reside on the abluminal surface of capillaries, and their processes cover ~90% of the length of the capillary bed. These cells were first described almost 150 years ago (Eberth, 1871; Rouget, 1873) and have been the subject of intense experimental scrutiny in recent years, but their physiological roles remain uncertain and little is known of the complement of signaling elements that they employ to carry out their functions. In this review, we synthesize functional data with single-cell RNAseq screens to explore the ion channel and G protein-coupled receptor (GPCR) toolkit of mesh and thin-strand pericytes of the brain, with the aim of providing a framework for deeper explorations of the molecular mechanisms that govern pericyte physiology. We argue that their complement of channels and receptors ideally positions capillary pericytes to play a central role in adapting blood flow to meet the challenge of satisfying neuronal energy requirements from deep within the capillary bed, by enabling dynamic regulation of their membrane potential to influence the electrical output of the cell. In particular, we outline how genetic and functional evidence suggest an important role for Gs-coupled GPCRs and ATP-sensitive potassium (KATP) channels in this context. We put forth a predictive model for long-range hyperpolarizing electrical signaling from pericytes to upstream arterioles, and detail the TRP and Ca2+ channels and Gq, Gi/o, and G12/13 signaling processes that counterbalance this. We underscore critical questions that need to be addressed to further advance our understanding of the signaling topology of capillary pericytes, and how this contributes to their physiological roles and their dysfunction in disease.
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Affiliation(s)
- Ashwini Hariharan
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Nick Weir
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Colin Robertson
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Liqun He
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Christer Betsholtz
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.,Department of Medicine Huddinge (MedH), Karolinska Institutet & Integrated Cardio Metabolic Centre, Huddinge, Sweden
| | - Thomas A Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
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Ribeiro VT, de Souza LC, Simões E Silva AC. Renin-Angiotensin System and Alzheimer's Disease Pathophysiology: From the Potential Interactions to Therapeutic Perspectives. Protein Pept Lett 2020; 27:484-511. [PMID: 31886744 DOI: 10.2174/0929866527666191230103739] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 08/27/2019] [Accepted: 11/16/2019] [Indexed: 12/21/2022]
Abstract
New roles of the Renin-Angiotensin System (RAS), apart from fluid homeostasis and Blood Pressure (BP) regulation, are being progressively unveiled, since the discoveries of RAS alternative axes and local RAS in different tissues, including the brain. Brain RAS is reported to interact with pathophysiological mechanisms of many neurological and psychiatric diseases, including Alzheimer's Disease (AD). Even though AD is the most common cause of dementia worldwide, its pathophysiology is far from elucidated. Currently, no treatment can halt the disease course. Successive failures of amyloid-targeting drugs have challenged the amyloid hypothesis and increased the interest in the inflammatory and vascular aspects of AD. RAS compounds, both centrally and peripherally, potentially interact with neuroinflammation and cerebrovascular regulation. This narrative review discusses the AD pathophysiology and its possible interaction with RAS, looking forward to potential therapeutic approaches. RAS molecules affect BP, cerebral blood flow, neuroinflammation, and oxidative stress. Angiotensin (Ang) II, via angiotensin type 1 receptors may promote brain tissue damage, while Ang-(1-7) seems to elicit neuroprotection. Several studies dosed RAS molecules in AD patients' biological material, with heterogeneous results. The link between AD and clinical conditions related to classical RAS axis overactivation (hypertension, heart failure, and chronic kidney disease) supports the hypothesized role of this system in AD. Additionally, RAStargeting drugs as Angiotensin Converting Enzyme inhibitors (ACEis) and Angiotensin Receptor Blockers (ARBs) seem to exert beneficial effects on AD. Results of randomized controlled trials testing ACEi or ARBs in AD are awaited to elucidate whether AD-RAS interaction has implications on AD therapeutics.
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Affiliation(s)
- Victor Teatini Ribeiro
- Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Leonardo Cruz de Souza
- Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil.,Department of Internal Medicine, Service of Neurology, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Ana Cristina Simões E Silva
- Interdisciplinary Laboratory of Medical Investigation, Faculty of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil
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Watanabe N, Noda Y, Nemoto T, Iimura K, Shimizu T, Hotta H. Cerebral artery dilation during transient ischemia is impaired by amyloid β deposition around the cerebral artery in Alzheimer's disease model mice. J Physiol Sci 2020; 70:57. [PMID: 33302862 PMCID: PMC10718030 DOI: 10.1186/s12576-020-00785-8] [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: 06/29/2020] [Accepted: 11/21/2020] [Indexed: 11/10/2022]
Abstract
Transient ischemia is an exacerbation factor of Alzheimer's disease (AD). We aimed to examine the influence of amyloid β (Aβ) deposition around the cerebral (pial) artery in terms of diameter changes in the cerebral artery during transient ischemia in AD model mice (APPNL-G-F) under urethane anesthesia. Cerebral vasculature and Aβ deposition were examined using two-photon microscopy. Cerebral ischemia was induced by transient occlusion of the unilateral common carotid artery. The diameter of the pial artery was quantitatively measured. In wild-type mice, the diameter of arteries increased during occlusion and returned to their basal diameter after re-opening. In AD model mice, the artery response during occlusion differed depending on Aβ deposition sites. Arterial diameter changes at non-Aβ deposition site were similar to those in wild-type mice, whereas they were significantly smaller at Aβ deposition site. The results suggest that cerebral artery changes during ischemia are impaired by Aβ deposition.
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Affiliation(s)
- Nobuhiro Watanabe
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Yoshihiro Noda
- Animal Facility, Tokyo Metropolitan Institute of Gerontology, Tokyo, 173-0015, Japan
| | - Taeko Nemoto
- Animal Facility, Tokyo Metropolitan Institute of Gerontology, Tokyo, 173-0015, Japan
| | - Kaori Iimura
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo, 173-0015, Japan
| | - Takahiko Shimizu
- Aging Stress Response Research Project Team, National Center for Geriatrics and Gerontology, Aichi, 474-8511, Japan
| | - Harumi Hotta
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo, 173-0015, Japan.
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21
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Designing peptide nanoparticles for efficient brain delivery. Adv Drug Deliv Rev 2020; 160:52-77. [PMID: 33031897 DOI: 10.1016/j.addr.2020.10.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/28/2020] [Accepted: 10/01/2020] [Indexed: 12/12/2022]
Abstract
The targeted delivery of therapeutic compounds to the brain is arguably the most significant open problem in drug delivery today. Nanoparticles (NPs) based on peptides and designed using the emerging principles of molecular engineering show enormous promise in overcoming many of the barriers to brain delivery faced by NPs made of more traditional materials. However, shortcomings in our understanding of peptide self-assembly and blood-brain barrier (BBB) transport mechanisms pose significant obstacles to progress in this area. In this review, we discuss recent work in engineering peptide nanocarriers for the delivery of therapeutic compounds to the brain: from synthesis, to self-assembly, to in vivo studies, as well as discussing in detail the biological hurdles that a nanoparticle must overcome to reach the brain.
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Wu J, Zhang X, Azhati G, Li T, Xu G, Liu F. Retinal microvascular attenuation in mental cognitive impairment and Alzheimer's disease by optical coherence tomography angiography. Acta Ophthalmol 2020; 98:e781-e787. [PMID: 32153141 DOI: 10.1111/aos.14381] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 01/25/2020] [Indexed: 12/20/2022]
Abstract
PURPOSE To explore regional variation of the macular microvasculature in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD), also to detect the association between retinal macular microvascular parameters and the progress of preclinical AD. METHODS Prospective study of healthy controls, patients with MCI and patients with AD by using Optical coherence tomography angiography (OCT-A). We quantified foveal avascular zone (FAZ) areas, densities of the superficial retinal capillary plexuses (SRCP) and deep retinal capillary plexuses (DRCP). The SRCP and DRCP were divided into inner (3 mm) and external (6 mm) annular rings, each containing four quadrants (SI, II, TI, NI, SE, IE, TE and NE). The data were analysed statistically by using SPSS 22 software. RESULTS Totally, 60 subjects including 21 HC (33 eyes), 21 patients with MCI (32 eyes) and 18 AD patients (28 eyes) were recruited. The microvascular densities of DRCP at all quadrants of the parafovea and perifovea were significantly lower in AD patients compared to HC group (p < 0.05). Compared to the HCs, MCI patients showed significant microvascular loss in most sectors of the parafovea and the SE sector of the DRCP (p < 0.05), but not in the parafovea (p = 0.829) or perifovea (p = 0.824) of the SRCP. No significant difference was found in microvascular density of SRCP among the groups, except at SI between the AD and HC groups (p = 0.048). CONCLUSION Our findings demonstrated the macular microvascular attenuation in MCI and AD patients. Both AD and MCI patients showed retinal microvascular density loss, which is more significant in the deep retinal capillary plexuses. Optical coherence tomography angiography (OCT-A) can be used to identify early microvascular abnormalities in AD and MCI. Quantified microvascular density in the DRCP might serve as potential biomarkers of early sign of AD then contribute to forestall the progression of preclinical AD.
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Affiliation(s)
- Jing Wu
- Department of Ophthalmology Shanghai Tenth People's Hospital Tongji University Shanghai China
- School of Medicine Tongji University Shanghai China
| | - Xiaojun Zhang
- Department of Neurology OSF St. Francis Medical Center University of Illinois College of Medicine Peoria Peoria Illinois USA
| | - Guliqiwaer Azhati
- Department of Ophthalmology Shanghai Tenth People's Hospital Tongji University Shanghai China
| | - Tingting Li
- Department of Ophthalmology Clinical Medical College of Shanghai Tenth People's Hospital of Nanjing Medical University Shanghai China
| | - Guoxing Xu
- Department of Ophthalmology The First Affiliated Hospital of Fujian Medical University Fuzhou China
| | - Fang Liu
- Department of Ophthalmology Shanghai Tenth People's Hospital Tongji University Shanghai China
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Samora M, Vianna LC, Carmo JC, Macedo V, Dawes M, Phillips AA, Paton JFR, Fisher JP. Neurovascular coupling is not influenced by lower body negative pressure in humans. Am J Physiol Heart Circ Physiol 2020; 319:H22-H31. [PMID: 32442032 DOI: 10.1152/ajpheart.00076.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cerebral blood flow is tightly coupled with local neuronal activation and metabolism, i.e., neurovascular coupling (NVC). Studies suggest a role of sympathetic nervous system in the regulation of cerebral blood flow. However, this is controversial, and the sympathetic regulation of NVC in humans remains unclear. Since impaired NVC has been identified in several chronic diseases associated with a heightened sympathetic activity, we aimed to determine whether reflex-mediated sympathetic activation via lower body negative pressure (LBNP) attenuates NVC in humans. NVC was assessed using a visual stimulation protocol (5 cycles of 30 s eyes closed and 30 s of reading) in 11 healthy participants (aged 24 ± 3 yr). NVC assessments were made under control conditions and during LBNP at -20 and -40 mmHg. Posterior (PCA) and middle (MCA) cerebral artery mean blood velocity (Vmean) and vertebral artery blood flow (VAflow) were simultaneously determined with cardiorespiratory variables. Under control conditions, the visual stimulation evoked a robust increase in PCAVmean (∆18.0 ± 4.5%), a moderate rise in VAflow (∆9.6 ± 4.3%), and a modest increase in MCAVmean (∆3.0 ± 1.9%). The magnitude of NVC response was not affected by mild-to-moderate LBNP (all P > 0.05 for repeated-measures ANOVA). Given the small change that occurred in partial pressure of end-tidal CO2 during LBNP, this hypocapnia condition was matched via voluntary hyperventilation in absence of LBNP in a subgroup of participants (n = 8). The mild hypocapnia during LBNP did not exert a confounding influence on the NVC response. These findings indicate that the NVC is not influenced by LBNP or mild hypocapnia in humans.NEW & NOTEWORTHY Visual stimulation evoked a robust increase in posterior cerebral artery velocity and a modest increase in vertebral artery blood flow, i.e., neurovascular coupling (NVC), which was unaffected by lower body negative pressure (LBNP) in humans. In addition, although LBNP induced a mild hypocapnia, this degree of hypocapnia in the absence of LBNP failed to modify the NVC response.
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Affiliation(s)
- Milena Samora
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.,NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Distrito Federal, Brazil
| | - Lauro C Vianna
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Distrito Federal, Brazil
| | - Jake C Carmo
- Biomechanics and Biological Signal Processing Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Distrito Federal, Brazil
| | - Victor Macedo
- Biomechanics and Biological Signal Processing Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Distrito Federal, Brazil
| | - Matthew Dawes
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Aaron A Phillips
- Departments of Physiology, Pharmacology, and Clinical Neurosciences, Libin Cardiovascular Institute, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Julian F R Paton
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - James P Fisher
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Marmarelis VZ, Shin DC, Oesterreich M, Mueller M. Quantification of dynamic cerebral autoregulation and CO 2 dynamic vasomotor reactivity impairment in essential hypertension. J Appl Physiol (1985) 2020; 128:397-409. [PMID: 31917625 DOI: 10.1152/japplphysiol.00620.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The study of dynamic cerebral autoregulation (DCA) in essential hypertension has received considerable attention because of its clinical importance. Several studies have examined the dynamic relationship between spontaneous beat-to-beat arterial blood pressure data and contemporaneous cerebral blood flow velocity measurements (obtained via transcranial Doppler at the middle cerebral arteries) in the form of a linear input-output model using transfer function analysis. This analysis is more reliable when the contemporaneous effects of changes in blood CO2 tension are also taken into account, because of the significant effects of CO2 dynamic vasomotor reactivity (DVR) upon cerebral flow. In this article, we extract such input-output predictive models from spontaneous time series hemodynamic data of 24 patients with essential hypertension and 20 normotensive control subjects under resting conditions, using the novel methodology of principal dynamic modes (PDMs) that achieves improved estimation accuracy over previous methods for relatively short and noisy data. The obtained data-based models are subsequently used to compute indexes and markers that quantify DCA and DVR in each subject or patient and therefore can be used to assess the effects of essential hypertension. These model-based DCA and DVR indexes were properly defined to capture the observed effects of DCA and VR and found to be significantly different (P < 0.05) in the hypertensive patients. We also found significant differences between patients and control subjects in the relative contribution of three PDMs to the model output prediction, a finding that offers the prospect of identifying the physiological mechanisms affected by essential hypertension when the PDMs are interpreted in terms of specific physiological mechanisms.NEW & NOTEWORTHY This article presents novel model-based methodology for obtaining diagnostic indexes of dynamic cerebral autoregulation and dynamic vasomotor reactivity in hypertension.
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Affiliation(s)
- Vasilis Z Marmarelis
- Biomedical Simulations Resource Center, University of Southern California, Los Angeles, California
| | - Dae C Shin
- Biomedical Simulations Resource Center, University of Southern California, Los Angeles, California
| | | | - Martin Mueller
- Neurocenter, Luzerner Kantonsspital, Lucerne, Switzerland
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25
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Solis E, Hascup KN, Hascup ER. Alzheimer's Disease: The Link Between Amyloid-β and Neurovascular Dysfunction. J Alzheimers Dis 2020; 76:1179-1198. [PMID: 32597813 PMCID: PMC7483596 DOI: 10.3233/jad-200473] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
While prevailing evidence supports that the amyloid cascade hypothesis is a key component of Alzheimer's disease (AD) pathology, many recent studies indicate that the vascular system is also a major contributor to disease progression. Vascular dysfunction and reduced cerebral blood flow (CBF) occur prior to the accumulation and aggregation of amyloid-β (Aβ) plaques and hyperphosphorylated tau tangles. Although research has predominantly focused on the cellular processes involved with Aβ-mediated neurodegeneration, effects of Aβ on CBF and neurovascular coupling are becoming more evident. This review will describe AD vascular disturbances as they relate to Aβ, including chronic cerebral hypoperfusion, hypertension, altered neurovascular coupling, and deterioration of the blood-brain barrier. In addition, we will describe recent findings about the relationship between these vascular defects and Aβ accumulation with emphasis on in vivo studies utilizing rodent AD models.
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Affiliation(s)
- Ernesto Solis
- Department of Neurology, Neuroscience Institute, Center for Alzheimer’s Disease and Related Disorders, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Kevin N. Hascup
- Department of Neurology, Neuroscience Institute, Center for Alzheimer’s Disease and Related Disorders, Southern Illinois University School of Medicine, Springfield, IL, USA
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
- Department of Medical Microbiology, Immunology, and Cell Biology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Erin R. Hascup
- Department of Neurology, Neuroscience Institute, Center for Alzheimer’s Disease and Related Disorders, Southern Illinois University School of Medicine, Springfield, IL, USA
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, USA
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26
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Marmarelis VZ, Shin DC, Zhang R. Dysregulation of CO2-Driven Heart-Rate Chemoreflex Is Related Closely to Impaired CO2 Dynamic Vasomotor Reactivity in Mild Cognitive Impairment Patients. J Alzheimers Dis 2020; 75:855-870. [PMID: 32333588 PMCID: PMC7369119 DOI: 10.3233/jad-191238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/18/2020] [Indexed: 11/15/2022]
Abstract
BACKGROUND Significant reduction of dynamic vasomotor reactivity (DVR) was recently reported in patients with amnestic mild cognitive impairment (MCI) relative to age-matched controls. These results were obtained via a novel approach that utilizes data-based predictive dynamic models to quantify DVR. OBJECTIVE Using the same methodological approach, we seek to quantify the dynamic effects of the CO2-driven chemoreflex and baroreflex upon heart-rate in order to examine their possible correlation with the observed DVR impairment in each MCI patient. METHODS The employed approach utilizes time-series data to obtain subject-specific predictive input-output models of the dynamic effects of changes in arterial blood pressure and end-tidal CO2 (putative "inputs") upon cerebral blood flow velocity in large cerebral arteries, cortical tissue oxygenation, and heart-rate (putative "outputs"). RESULTS There was significant dysregulation of CO2-driven heart-rate chemoreflex (p = 0.0031), but not of baroreflex (p = 0.5061), in MCI patients relative to age-matched controls. The model-based index of CO2-driven heart-rate chemoreflex gain (CRG) correlated significantly with the DVR index in large cerebral arteries (p = 0.0146), but not with the DVR index in small/micro-cortical vessels (p = 0.1066). This suggests that DVR impairment in small/micro-cortical vessels is not mainly due to CO2-driven heart-rate chemoreflex dysregulation, but to other factors (possibly dysfunction of neurovascular coupling). CONCLUSION Improved delineation between MCI patients and controls is achieved by combining the DVR index for small/micro-cortical vessels with the CRG index (p = 2×10-5). There is significant correlation (p < 0.01) between neuropsychological test scores and model-based DVR indices. Combining neuropsychological scores with DVR indices reduces the composite diagnostic index p-value (p∼10-10).
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Affiliation(s)
| | - Dae C. Shin
- Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Rong Zhang
- Internal Medicine, Neurology & Neurotherapeutics, UT Southwestern Medical Center, Dallas, TX, USA
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27
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Ji B, Wang Q, Xue Q, Li W, Li X, Wu Y. The Dual Role of Kinin/Kinin Receptors System in Alzheimer's Disease. Front Mol Neurosci 2019; 12:234. [PMID: 31632239 PMCID: PMC6779775 DOI: 10.3389/fnmol.2019.00234] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 09/13/2019] [Indexed: 11/30/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common neurodegenerative disease characterized by progressive spatial disorientation, learning and memory deficits, responsible for 60%–80% of all dementias. However, the pathological mechanism of AD remains unknown. Numerous studies revealed that kinin/kinin receptors system (KKS) may be involved in the pathophysiology of AD. In this review article, we summarized the roles of KKS in neuroinflammation, cerebrovascular impairment, tau phosphorylation, and amyloid β (Aβ) generation in AD. Moreover, we provide new insights into the mechanistic link between KKS and AD, and highlight the KKS as a potential therapeutic target for AD treatment.
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Affiliation(s)
- Bingyuan Ji
- Neurobiology Institute, School of Mental Health, Jining Medical University, Jining, China
| | - Qinqin Wang
- Neurobiology Institute, School of Mental Health, Jining Medical University, Jining, China
| | - Qingjie Xue
- Department of Pathogenic Biology, Jining Medical University, Jining, China
| | - Wenfu Li
- Neurobiology Institute, School of Mental Health, Jining Medical University, Jining, China
| | - Xuezhi Li
- Shandong Collaborative Innovation Center for Diagnosis, Treatment and Behavioral Interventions of Mental Disorders, Institute of Mental Health, Jining Medical University, Jining, China.,Shandong Key Laboratory of Behavioral Medicine, School of Mental Health, Jining Medical University, Jining, China
| | - Yili Wu
- Shandong Collaborative Innovation Center for Diagnosis, Treatment and Behavioral Interventions of Mental Disorders, Institute of Mental Health, Jining Medical University, Jining, China.,Shandong Key Laboratory of Behavioral Medicine, School of Mental Health, Jining Medical University, Jining, China
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28
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Csipo T, Mukli P, Lipecz A, Tarantini S, Bahadli D, Abdulhussein O, Owens C, Kiss T, Balasubramanian P, Nyúl-Tóth Á, Hand RA, Yabluchanska V, Sorond FA, Csiszar A, Ungvari Z, Yabluchanskiy A. Assessment of age-related decline of neurovascular coupling responses by functional near-infrared spectroscopy (fNIRS) in humans. GeroScience 2019; 41:495-509. [PMID: 31676966 PMCID: PMC6885078 DOI: 10.1007/s11357-019-00122-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 10/11/2019] [Indexed: 12/31/2022] Open
Abstract
Preclinical studies provide strong evidence that age-related impairment of neurovascular coupling (NVC) plays a causal role in the pathogenesis of vascular cognitive impairment (VCI). NVC is a critical homeostatic mechanism in the brain, responsible for adjustment of local cerebral blood flow to the energetic needs of the active neuronal tissue. Recent progress in geroscience has led to the identification of critical cellular and molecular mechanisms involved in neurovascular aging, identifying these pathways as targets for intervention. In order to translate the preclinical findings to humans, there is a need to assess NVC in geriatric patients as an endpoint in clinical studies. Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that enables the investigation of local changes in cerebral blood flow, quantifying task-related changes in oxygenated and deoxygenated hemoglobin concentrations. In the present overview, the basic principles of fNIRS are introduced and the application of this technique to assess NVC in older adults with implications for the design of studies on the mechanistic underpinnings of VCI is discussed.
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Affiliation(s)
- Tamas Csipo
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- Division of Clinical Physiology, Department of Cardiology / Kálmán Laki Doctoral School of Biomedical and Clinical Sciences, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
| | - Peter Mukli
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Agnes Lipecz
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- Department of Ophthalmology, Josa Andras Hospital, Nyiregyhaza, Hungary
| | - Stefano Tarantini
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
| | - Dhay Bahadli
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
| | - Osamah Abdulhussein
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
| | - Cameron Owens
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
| | - Tamas Kiss
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Theoretical Medicine Doctoral School/Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Priya Balasubramanian
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
| | - Ádám Nyúl-Tóth
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- Institute of Biophysics, Biological Research Centre, Szeged, Hungary
| | - Rachel A Hand
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
| | - Valeriya Yabluchanska
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- Bon Secours, St. Francis Family Medicine Center, Midlothian, VA, USA
| | - Farzaneh A Sorond
- Department of Neurology, Division of Stroke and Neurocritical Care, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Anna Csiszar
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Theoretical Medicine Doctoral School/Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Zoltan Ungvari
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Department of Public Health, Semmelweis University, Budapest, Hungary
- International Training Program in Geroscience, Theoretical Medicine Doctoral School/Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Andriy Yabluchanskiy
- Vascular Cognitive Impairment and Neurodegeneration Program, Oklahoma Center for Geroscience and Healthy Brain Aging, Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10th Street, BRC 1311, Oklahoma City, OK, 73104, USA.
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Chronic Cerebral Hypoperfusion Activates the Coagulation and Complement Cascades in Alzheimer's Disease Mice. Neuroscience 2019; 416:126-136. [DOI: 10.1016/j.neuroscience.2019.07.050] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 12/22/2022]
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30
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McConnell HL, Li Z, Woltjer RL, Mishra A. Astrocyte dysfunction and neurovascular impairment in neurological disorders: Correlation or causation? Neurochem Int 2019; 128:70-84. [PMID: 30986503 DOI: 10.1016/j.neuint.2019.04.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 12/14/2022]
Abstract
The neurovascular unit, consisting of neurons, astrocytes, and vascular cells, has become the focus of much discussion in the last two decades and emerging literature now suggests an association between neurovascular dysfunction and neurological disorders. In this review, we synthesize the known and suspected contributions of astrocytes to neurovascular dysfunction in disease. Throughout the brain, astrocytes are centrally positioned to dynamically mediate interactions between neurons and the cerebral vasculature, and play key roles in blood-brain barrier maintenance and neurovascular coupling. It is increasingly apparent that the changes in astrocytes in response to a variety of insults to brain tissue -collectively referred to as "reactive astrogliosis" - are not just an epiphenomenon restricted to morphological alterations, but comprise functional changes in astrocytes that contribute to the phenotype of neurological diseases with both beneficial and detrimental effects. In the context of the neurovascular unit, astrocyte dysfunction accompanies, and may contribute to, blood-brain barrier impairment and neurovascular dysregulation, highlighting the need to determine the exact nature of the relationship between astrocyte dysfunction and neurovascular impairments. Targeting astrocytes may represent a new strategy in combinatorial therapeutics for preventing the mismatch of energy supply and demand that often accompanies neurological disorders.
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Affiliation(s)
- Heather L McConnell
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
| | - Zhenzhou Li
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States; Department of Anesthesiology, General Hospital of Ningxia Medical University, Yinchuan City, China
| | - Randall L Woltjer
- Department of Neuropathology, Oregon Health & Science University, Portland, OR, United States
| | - Anusha Mishra
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States.
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31
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Disturbed neurovascular coupling in type 2 diabetes mellitus patients: Evidence from a comprehensive fMRI analysis. NEUROIMAGE-CLINICAL 2019; 22:101802. [PMID: 30991623 PMCID: PMC6447740 DOI: 10.1016/j.nicl.2019.101802] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 03/12/2019] [Accepted: 03/26/2019] [Indexed: 02/08/2023]
Abstract
Background Previous studies presumed that the disturbed neurovascular coupling to be a critical risk factor of cognitive impairments in type 2 diabetes mellitus (T2DM), but distinct clinical manifestations were lacked. Consequently, we decided to investigate the neurovascular coupling in T2DM patients by exploring the MRI relationship between neuronal activity and the corresponding cerebral blood perfusion. Methods Degree centrality (DC) map and amplitude of low-frequency fluctuation (ALFF) map were used to represent neuronal activity. Cerebral blood flow (CBF) map was used to represent cerebral blood perfusion. Correlation coefficients were calculated to reflect the relationship between neuronal activity and cerebral blood perfusion. Results At the whole gray matter level, the manifestation of neurovascular coupling was investigated by using 4 neurovascular biomarkers. We compared these biomarkers and found no significant changes. However, at the brain region level, neurovascular biomarkers in T2DM patients were significantly decreased in 10 brain regions. ALFF-CBF in left hippocampus and fractional ALFF-CBF in left amygdala were positively associated with the executive function, while ALFF-CBF in right fusiform gyrus was negatively related to the executive function. The disease severity was negatively related to the memory and executive function. The longer duration of T2DM was related to the milder depression, which suggests T2DM-related depression may not be a physiological condition but be a psychological condition. Conclusion Correlations between neuronal activity and cerebral perfusion maps may be a method for detecting neurovascular coupling abnormalities, which could be used for diagnosis in the future. Trial registry number: This study has been registered in ClinicalTrials.gov (NCT02420470) on April 2, 2015 and published on July 29, 2015. Multi-modal MRI is a method to reflect neurovascular coupling condition. Neurovascular coupling dysfunction was found in diabetics. The memory, executive function and emotion were disrupted in diabetics. The limbic system, basal ganglia, and prefrontal lobe was damaged in diabetics.
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32
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Hariharan A, Jing Y, Collie ND, Zhang H, Liu P. Altered neurovascular coupling and brain arginine metabolism in endothelial nitric oxide synthase deficient mice. Nitric Oxide 2019; 87:60-72. [PMID: 30877024 DOI: 10.1016/j.niox.2019.03.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 03/06/2019] [Accepted: 03/10/2019] [Indexed: 12/23/2022]
Abstract
Nitric oxide (NO) produced by endothelial NO synthase (eNOS) is a key regulator of cerebral blood flow (CBF) dynamics. Mice with eNOS deficiency (eNOS-/-) display age-related increases in amyloid beta in the brain and memory deficits, implicating eNOS dysfunction in the neuropathogenesis and/or development of Alzheimer's disease (AD). The present study systematically investigated behavioural, CBF and brain arginine metabolic profile changes in male and female wildtype (WT) and eNOS-/- mice at 14 months of age. eNOS-/- mice displayed altered behaviour in the Y-maze and open field tests. A real-time microcirculation imager revealed a significant sex difference in the basal CBF and significantly increased perfusion response to whisker stimulations in the Barrel cortex in both male and female eNOS-/- mice relative to their sex-matched WT controls. The treatment of 7-nitroindazole blocked the increased perfusion response to whisker stimulations in eNOS-/- mice. Neurochemically, the most intriguing changes were markedly reduced glutamine levels in both male and female eNOS-/- mice in the frontal cortex, hippocampus, parahippocampal region and cerebellum. These findings demonstrate altered behavioural function, neurovascular coupling and brain arginine metabolism (glutamine in particular) under the condition of eNOS deficiency, which further supports the role of eNOS dysfunction in the AD neuropathogenesis.
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Affiliation(s)
- Ashwini Hariharan
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Brain Research New Zealand, New Zealand
| | - Yu Jing
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Brain Research New Zealand, New Zealand
| | - Nicola D Collie
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Brain Research New Zealand, New Zealand
| | - Hu Zhang
- School of Pharmacy, Brain Health Research Centre, University of Otago, Brain Research New Zealand, New Zealand
| | - Ping Liu
- Department of Anatomy, School of Biomedical Sciences, Brain Health Research Centre, University of Otago, Brain Research New Zealand, New Zealand.
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Guo Y, Li X, Zhang M, Chen N, Wu S, Lei J, Wang Z, Wang R, Wang J, Liu H. Age‑ and brain region‑associated alterations of cerebral blood flow in early Alzheimer's disease assessed in AβPPSWE/PS1ΔE9 transgenic mice using arterial spin labeling. Mol Med Rep 2019; 19:3045-3052. [PMID: 30816468 PMCID: PMC6423566 DOI: 10.3892/mmr.2019.9950] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 02/06/2019] [Indexed: 02/07/2023] Open
Abstract
It has been suggested that cerebral blood flow (CBF) alterations may be involved in the pathogenesis of Alzheimer's disease (AD). However, how CBF changes with age has not been detailed in AD, particularly in its early stages. The objective of the present study was to evaluate CBF in four brain regions (the hippocampus, entorhinal cortex, frontoparietal cortex and thalamus) of mice in four age groups, to mimic the respective stages of AD in humans [2 months (pre-clinical), 3.5 months (sub-clinical), 5 months (early-clinical) and 8 months (mid-clinical)], to understand the age-associated changes in selected brain regions and to elucidate the underlying vascular mechanisms. CBF was measured using magnetic resonance imaging-arterial spin labelling (ASL) under identical conditions across the age groups of AβPPSWE/PS1ΔE9 (APP/PS1) transgenic mice with AD. The results indicated age- and brain region-associated changes in CBF were associated with early AD. More precisely, an age-dependent increase in CBF (in the pre- and sub-clinical AD groups) was observed in the frontoparietal cortex and thalamus. Conversely, increased CBF demonstrated an age-dependent decline (in the early- and mid-clinical AD groups) in all examined brain regions. Among the regions, the thalamus had the greatest increase in CBF in the 2 and 3.5 months age groups, which was substantially different compared with the age-matched controls. An extension of vessel area was also noted to be age- and brain region-dependent. In particular, correlation analysis revealed significant associations of CBF with vessel area in the frontoparietal cortex and thalamus of APP/PS1 mice at ages 2 and 3.5 months, indicating that CBF increase may arise from vessel extension. The results of the present study suggested that ASL can detect age- and brain region-associated changes in CBF in mice with AD, and that ASL-measured CBF increase may be a potential diagnostic biomarker for early AD. The observation that CBF increase resulted from vessel extension may aid in the understanding of the vascular role in age-associated development of AD pathology, and provide preclinical evidence for AD patient management.
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Affiliation(s)
- Yapei Guo
- Department of Neurology, The Fifth Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Xueyuan Li
- Department of Neurosurgery, The First Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Min Zhang
- Department of Neurology, The Fifth Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Ningning Chen
- Department of Neurology, The Fifth Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Shitao Wu
- Department of Neurology, The Fifth Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Jianfeng Lei
- Center for Medical Experiments and Testing, Capital Medical University, Beijing 100069, P.R. China
| | - Zhanjing Wang
- Center for Medical Experiments and Testing, Capital Medical University, Beijing 100069, P.R. China
| | - Renzhi Wang
- Department of Neurosurgery, Peking Union Medical College Hospital, Beijing 100052, P.R. China
| | - Jianping Wang
- Department of Neurology, The Fifth Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Hengfang Liu
- Department of Neurology, The Fifth Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
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Mouse models of Alzheimer's disease cause rarefaction of pial collaterals and increased severity of ischemic stroke. Angiogenesis 2019; 22:263-279. [PMID: 30519973 PMCID: PMC6475514 DOI: 10.1007/s10456-018-9655-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2018] [Accepted: 11/20/2018] [Indexed: 01/26/2023]
Abstract
Vascular dysfunction contributes to the progression and severity of Alzheimer's disease (AD). Patients with AD also sustain larger infarctions after ischemic stroke; however, the responsible mechanisms are unknown. Pial collaterals are the primary source of protection in stroke. Unfortunately, natural aging and other vascular risk factors cause a decline in collateral number and diameter (rarefaction) and an increase in stroke severity. Herein, we tested the hypothesis that AD accelerates age-induced collateral rarefaction and examined potential underlying mechanisms. Triple and double transgenic mouse models of AD both sustained collateral rarefaction by 8 months of age, well before the onset of rarefaction caused by aging alone (16 months of age). Rarefaction, which did not progress further at 18 months of age, was accompanied by a twofold increase in infarct volume after MCA occlusion. AD did not induce rarefaction of similarly sized pial arterioles or penetrating arterioles. Rarefaction was minimal and occurred only at 18 months of age in a parenchymal vascular amyloid-beta model of AD. Rarefaction was not associated with amyloid-beta deposition on collaterals or pial arteries, nor was plaque burden or CD11b+ cell density greater in brain underlying the collateral zones versus elsewhere. However, rarefaction was accompanied by increased markers of oxidative stress, inflammation, and aging of collateral endothelial and mural cells. Moreover, rarefaction was lessened by deletion of CX3CR1 and prevented by overexpression of eNOS. These findings demonstrate that mouse models of AD promote rarefaction of pial collaterals and implicate inflammation-induced accelerated aging of collateral wall cells. Strategies that reduce vascular inflammation and/or increase nitric oxide may preserve collateral function.
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Parahippocampal gyrus expression of endothelial and insulin receptor signaling pathway genes is modulated by Alzheimer's disease and normalized by treatment with anti-diabetic agents. PLoS One 2018; 13:e0206547. [PMID: 30383799 PMCID: PMC6211704 DOI: 10.1371/journal.pone.0206547] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 10/15/2018] [Indexed: 12/14/2022] Open
Abstract
A large body of literature links risk of cognitive decline, mild cognitive impairment (MCI) and dementia with Type 2 Diabetes (T2D) or pre-diabetes. Accumulating evidence implicates a close relationship between the brain insulin receptor signaling pathway (IRSP) and the accumulation of amyloid beta and hyperphosphorylated and conformationally abnormal tau. We showed previously that the neuropathological features of Alzheimer's disease (AD were reduced in patients with diabetes who were treated with insulin and oral antidiabetic medications. To understand better the neurobiological substrates of T2D and T2D medications in AD, we examined IRSP and endothelial cell markers in the parahippocampal gyrus of controls (N = 30), of persons with AD (N = 19), and of persons with AD and T2D, who, in turn, had been treated with anti-diabetic drugs (insulin and or oral agents; N = 34). We studied the gene expression of selected members of the IRSP and selective endothelial cell markers in bulk postmortem tissue from the parahippocampal gyrus and in endothelial cell enriched isolates from the same brain region. The results indicated that there are considerable abnormalities and reductions in gene expression (bulk tissue homogenates and endothelial cell isolates) in the parahippocampal gyri of persons with AD that map directly to genes associated with the microvasculature and the IRSP. Our results also showed that the numbers of abnormally expressed microvasculature and IRSP associated genes in diabetic AD donors who had been treated with anti-diabetic agents were reduced significantly. These findings suggest that anti-diabetic treatments may reduce or normalize compromised microvascular and IRSP functions in AD.
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Hoyk Z, Tóth ME, Lénárt N, Nagy D, Dukay B, Csefová A, Zvara Á, Seprényi G, Kincses A, Walter FR, Veszelka S, Vígh J, Barabási B, Harazin A, Kittel Á, Puskás LG, Penke B, Vígh L, Deli MA, Sántha M. Cerebrovascular Pathology in Hypertriglyceridemic APOB-100 Transgenic Mice. Front Cell Neurosci 2018; 12:380. [PMID: 30410436 PMCID: PMC6209654 DOI: 10.3389/fncel.2018.00380] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 10/04/2018] [Indexed: 01/08/2023] Open
Abstract
Hypertriglyceridemia is not only a serious risk factor in the development of cardiovascular diseases, but it is linked to neurodegeneration, too. Previously, we generated transgenic mice overexpressing the human APOB-100 protein, a mouse model of human atherosclerosis. In this model we observed high plasma levels of triglycerides, oxidative stress, tau hyperphosphorylation, synaptic dysfunction, cognitive impairment, increased neural apoptosis and neurodegeneration. Neurovascular dysfunction is recognized as a key factor in the development of neurodegenerative diseases, but the cellular and molecular events linking cerebrovascular pathology and neurodegeneration are not fully understood. Our aim was to study cerebrovascular changes in APOB-100 transgenic mice. We described the kinetics of the development of chronic hypertriglyceridemia in the transgenic animals. Increased blood-brain barrier permeability was found in the hippocampus of APOB-100 transgenic mice which was accompanied by structural changes. Using transmission electron microscopy, we detected changes in the brain capillary endothelial tight junction structure and edematous swelling of astrocyte endfeet. In brain microvessels isolated from APOB-100 transgenic animals increased Lox-1, Aqp4, and decreased Meox-2, Mfsd2a, Abcb1a, Lrp2, Glut-1, Nos2, Nos3, Vim, and in transgenic brains reduced Cdh2 and Gfap-σ gene expressions were measured using quantitative real-time PCR. We confirmed the decreased P-glycoprotein (ABCB1) and vimentin expression related to the neurovascular unit by immunostaining in transgenic brain sections using confocal microscopy. We conclude that in chronic hypertriglyceridemic APOB-100 transgenic mice both functional and morphological cerebrovascular pathology can be observed, and this animal model could be a useful tool to study the link between cerebrovascular pathology and neurodegeneration.
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Affiliation(s)
- Zsófia Hoyk
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Melinda E Tóth
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Nikolett Lénárt
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Dóra Nagy
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Brigitta Dukay
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Alexandra Csefová
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Ágnes Zvara
- Laboratory of Functional Genomics, Core Facilities, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - György Seprényi
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - András Kincses
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Fruzsina R Walter
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Szilvia Veszelka
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Judit Vígh
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Beáta Barabási
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - András Harazin
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Ágnes Kittel
- Laboratory of Molecular Pharmacology, Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - László G Puskás
- Laboratory of Functional Genomics, Core Facilities, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Botond Penke
- Department of Medical Chemistry, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - László Vígh
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Mária A Deli
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Miklós Sántha
- Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
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Lumsden AL, Rogers JT, Majd S, Newman M, Sutherland GT, Verdile G, Lardelli M. Dysregulation of Neuronal Iron Homeostasis as an Alternative Unifying Effect of Mutations Causing Familial Alzheimer's Disease. Front Neurosci 2018; 12:533. [PMID: 30150923 PMCID: PMC6099262 DOI: 10.3389/fnins.2018.00533] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/16/2018] [Indexed: 12/12/2022] Open
Abstract
The overwhelming majority of dominant mutations causing early onset familial Alzheimer’s disease (EOfAD) occur in only three genes, PSEN1, PSEN2, and APP. An effect-in-common of these mutations is alteration of production of the APP-derived peptide, amyloid β (Aβ). It is this key fact that underlies the authority of the Amyloid Hypothesis that has informed Alzheimer’s disease research for over two decades. Any challenge to this authority must offer an alternative explanation for the relationship between the PSEN genes and APP. In this paper, we explore one possible alternative relationship – the dysregulation of cellular iron homeostasis as a common effect of EOfAD mutations in these genes. This idea is attractive since it provides clear connections between EOfAD mutations and major characteristics of Alzheimer’s disease such as dysfunctional mitochondria, vascular risk factors/hypoxia, energy metabolism, and inflammation. We combine our ideas with observations by others to describe a “Stress Threshold Change of State” model of Alzheimer’s disease that may begin to explain the existence of both EOfAD and late onset sporadic (LOsAD) forms of the disease. Directing research to investigate the role of dysregulation of iron homeostasis in EOfAD may be a profitable way forward in our struggle to understand this form of dementia.
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Affiliation(s)
- Amanda L Lumsden
- College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia.,South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Jack T Rogers
- Neurochemistry Laboratory, Department of Psychiatry-Neuroscience, Massachusetts General Hospital (East), Harvard Medical School, Harvard University, Charlestown, MA, United States
| | - Shohreh Majd
- Neuronal Injury and Repair Laboratory, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Morgan Newman
- Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Greg T Sutherland
- Discipline of Pathology, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Giuseppe Verdile
- School of Pharmacy and Biomedical Sciences, Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, WA, Australia
| | - Michael Lardelli
- Centre for Molecular Pathology, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
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Ghaffari M, Sanchez L, Xu G, Alaraj A, Zhou XJ, Charbel FT, Linninger AA. Validation of parametric mesh generation for subject-specific cerebroarterial trees using modified Hausdorff distance metrics. Comput Biol Med 2018; 100:209-220. [PMID: 30048917 DOI: 10.1016/j.compbiomed.2018.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 07/02/2018] [Accepted: 07/05/2018] [Indexed: 01/19/2023]
Abstract
Accurate subject-specific vascular network reconstruction is a critical task for the hemodynamic analysis of cerebroarterial circulation. Vascular skeletonization and computational mesh generation for large sections of cerebrovascular trees from magnetic resonance angiography (MRA) is an error-prone, operator-dependent, and very time-consuming task. Validation of reconstructed computational models is essential to ascertain their accuracy and precision, which directly relates to the confidence of CFD computations performed on these meshes. The aim of this study is to generate an imaging segmentation pipeline to validate and quantify the spatial accuracy of computational models of subject-specific cerebral arterial trees. We used a recently introduced parametric structured mesh (PSM) generation method to automatically reconstruct six subject-specific cerebral arterial trees containing 1364 vessels and 571 bifurcations. By automatically extracting sampling frames for all vascular segments and bifurcations, we quantify the spatial accuracy of PSM against the original MRA images. Our comprehensive study correlates lumen area, pixel-based statistical analysis, area overlap and centerline accuracy measurements. In addition, we propose a new metric, the pointwise offset surface distance metric (PSD), to quantify the spatial alignment between dimensions of reconstructed arteries and bifurcations with in-vivo data with the ability to quantify the over- and under-approximation of the reconstructed models. Accurate reconstruction of vascular trees can a practical process tool for morphological analysis of large patient data banks, such as medical record files in hospitals, or subject-specific hemodynamic simulations of the cerebral arterial circulation.
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Affiliation(s)
- Mahsa Ghaffari
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Lea Sanchez
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Guoren Xu
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Ali Alaraj
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA; Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL, USA.
| | - Xiaohong Joe Zhou
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA; Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL, USA; Department of Radiology and Center for MR Research, University of Illinois at Chicago, Chicago, IL, USA
| | - Fady T Charbel
- Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL, USA
| | - Andreas A Linninger
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA; Department of Neurosurgery, University of Illinois at Chicago, Chicago, IL, USA.
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Abstract
Early blindness causes fundamental alterations of neural function across more than 25% of cortex-changes that span the gamut from metabolism to behavior and collectively represent one of the most dramatic examples of plasticity in the human brain. The goal of this review is to describe how the remarkable behavioral and neuroanatomical compensations demonstrated by blind individuals provide insights into the extent, mechanisms, and limits of human brain plasticity.
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Affiliation(s)
- Ione Fine
- Department of Psychology, University of Washington, Seattle, Washington 98195, USA;
| | - Ji-Min Park
- Department of Psychology, University of Washington, Seattle, Washington 98195, USA;
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Dong S, Maniar S, Manole MD, Sun D. Cerebral Hypoperfusion and Other Shared Brain Pathologies in Ischemic Stroke and Alzheimer's Disease. Transl Stroke Res 2018; 9:238-250. [PMID: 28971348 PMCID: PMC9732865 DOI: 10.1007/s12975-017-0570-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/05/2017] [Accepted: 09/13/2017] [Indexed: 12/13/2022]
Abstract
Newly emerged evidence reveals that ischemic stroke and Alzheimer's disease (AD) share pathophysiological changes in brain tissue including hypoperfusion, oxidative stress, immune exhaustion, and inflammation. A mechanistic link between hypoperfusion and amyloid β accumulation can lead to cell damage as well as to motor and cognitive deficits. This review will discuss decreased cerebral perfusion and other related pathophysiological changes common to both ischemic stroke and AD, such as vascular damages, cerebral blood flow alteration, abnormal expression of amyloid β and tau proteins, as well as behavioral and cognitive deficits. Furthermore, this review highlights current treatment options and potential therapeutic targets that warrant further investigation.
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Affiliation(s)
- Shuying Dong
- Department of Pharmacology, Bengbu Medical College, Bengbu, Anhui, China
- Department of Neurology, University of Pittsburgh, S-598 South Biomedical Science Tower, 3500 Terrace St., Pittsburgh, PA, 15213, USA
| | - Shelly Maniar
- Department of Neurology, University of Pittsburgh, S-598 South Biomedical Science Tower, 3500 Terrace St., Pittsburgh, PA, 15213, USA
- Lake Erie College of Osteopathic Medicine at Seton Hill, Greensburg, Pennsylvania, 15601, USA
| | - Mioara D Manole
- Department of Pediatrics, University of Pittsburgh, Pittsburgh, PA, USA
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, S-598 South Biomedical Science Tower, 3500 Terrace St., Pittsburgh, PA, 15213, USA.
- Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA, USA.
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Marchitelli R, Aiello M, Cachia A, Quarantelli M, Cavaliere C, Postiglione A, Tedeschi G, Montella P, Milan G, Salvatore M, Salvatore E, Baron JC, Pappatà S. Simultaneous resting-state FDG-PET/fMRI in Alzheimer Disease: Relationship between glucose metabolism and intrinsic activity. Neuroimage 2018; 176:246-258. [PMID: 29709628 DOI: 10.1016/j.neuroimage.2018.04.048] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 04/18/2018] [Accepted: 04/20/2018] [Indexed: 12/31/2022] Open
Abstract
Simultaneously evaluating resting-state brain glucose metabolism and intrinsic functional activity has potential to impact the clinical neurosciences of Alzheimer Disease (AD). Indeed, integrating such combined information obtained in the same physiological setting may clarify how impairments in neuroenergetic and neuronal function interact and contribute to the mechanisms underlying AD. The present study used this multimodality approach to investigate, by means of a hybrid PET/MR scanner, the coupling between glucose consumption and intrinsic functional activity in 23 patients with AD-related cognitive impairment ranging from amnestic mild cognitive impairment (MCI) to mild-moderate AD (aMCI/AD), in comparison with a group of 23 healthy elderly controls. Between-group (Controls > Patients) comparisons were conducted on data from both imaging modalities using voxelwise 2-sample t-tests, corrected for partial-volume effects, head motion, age, gender and multiple tests. FDG-PET/fMRI relationships were assessed within and across subjects using Spearman partial correlations for three different resting-state fMRI (rs-fMRI) metrics sensitive to AD: fractional amplitude of low frequency fluctuations (fALFF), regional homogeneity (ReHo) and group independent component analysis with dual regression (gICA-DR). FDG and rs-fMRI metrics distinguished aMCI/AD from controls according to spatial patterns analogous to those found in stand-alone studies. Within-subject correlations were comparable across the three rs-fMRI metrics. Correlations were overall high in healthy controls (ρ = 0.80 ± 0.04), but showed a significant 17% reduction (p < 0.05) in aMCI/AD patients (ρ = 0.67 ± 0.05). Positive across-subject correlations were overall moderate (ρ = 0.33 ± 0.07) and consistent across rs-fMRI metrics. These were confined around AD-target posterior regions for metrics of functional connectivity (ReHo and gICA-DR). In contrast, FDG/fALFF correlations were distributed in the frontal gyrus, thalami and caudate nuclei. Taken together, these results support the presence of bioenergetic coupling between glucose utilization and rapid transmission of neural information in healthy ageing, which is substantially reduced in aMCI/AD, suggesting that abnormal glucose utilization is in some way linked to communication breakdown among brain regions impacted by the underlying pathological process.
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Affiliation(s)
- Rocco Marchitelli
- IRCCS SDN, Institute of Nuclear and Diagnostic Research, Via E. Gianturco 113, 80143, Naples, Italy
| | - Marco Aiello
- IRCCS SDN, Institute of Nuclear and Diagnostic Research, Via E. Gianturco 113, 80143, Naples, Italy.
| | - Arnaud Cachia
- INSERM U894, Université Paris Descartes, Centre Hospitalier Sainte-Anne, Sorbonne Paris Cité, Paris, France; CNRS U8240, Université Paris Descartes, Sorbonne Paris Cité, Paris, France; Institut Universitaire de France, Paris, France
| | - Mario Quarantelli
- Institute of Biostructure and Bioimaging, National Research Council, Naples, Italy
| | - Carlo Cavaliere
- IRCCS SDN, Institute of Nuclear and Diagnostic Research, Via E. Gianturco 113, 80143, Naples, Italy
| | - Alfredo Postiglione
- Department of Clinical Medicine & Surgery, University of Naples "Federico II", Naples, Italy
| | - Gioacchino Tedeschi
- Dept of Medical, Surgical Neurological Metabolic and Aging Sciences. University of Campania "L. Vanvitelli", Italy
| | - Patrizia Montella
- Dept of Medical, Surgical Neurological Metabolic and Aging Sciences. University of Campania "L. Vanvitelli", Italy
| | - Graziella Milan
- Centro Geriatrico Frullone, ASL Napoli 1 Centro, Naples, Italy
| | - Marco Salvatore
- IRCCS SDN, Institute of Nuclear and Diagnostic Research, Via E. Gianturco 113, 80143, Naples, Italy
| | - Elena Salvatore
- Department of Neuroscience Reproductive Sciences and Odontostomatology, Federico II University, Naples, Italy
| | - Jean Claude Baron
- Dept of Neurology, Centre Hospitalier Sainte-Anne, Université Paris Descartes, INSERM U894, Paris, France
| | - Sabina Pappatà
- Institute of Biostructure and Bioimaging, National Research Council, Naples, Italy
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Kenney K, Amyot F, Moore C, Haber M, Turtzo LC, Shenouda C, Silverman E, Gong Y, Qu BX, Harburg L, Wassermann EM, Lu H, Diaz‐Arrastia R. Phosphodiesterase-5 inhibition potentiates cerebrovascular reactivity in chronic traumatic brain injury. Ann Clin Transl Neurol 2018; 5:418-428. [PMID: 29687019 PMCID: PMC5899908 DOI: 10.1002/acn3.541] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 12/12/2017] [Accepted: 12/26/2017] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Traumatic cerebrovascular injury (TCVI), a common consequence of traumatic brain injury (TBI), presents an attractive therapeutic target. Because phosphodiesterase-5 (PDE5) inhibitors potentiate the action of nitric oxide (NO) produced by endothelial cells, they are candidate therapies for TCVI. This study aims to: (1) measure cerebral blood flow (CBF), cerebrovascular reactivity (CVR), and change in CVR after a single dose of sildenafil (ΔCVR) in chronic TBI compared to uninjured controls; (2) examine the safety and tolerability of 8-week sildenafil administration in chronic symptomatic moderate/severe TBI patients; and as an exploratory aim, (3) assess the effect of an 8-week course of sildenafil on chronic TBI symptoms. METHODS Forty-six subjects (31 chronic TBI, 15 matched healthy volunteers) were enrolled. Baseline CBF and CVR before and after administration of sildenafil were measured. Symptomatic TBI subjects then completed an 8-week double-blind, placebo-controlled, crossover trial of sildenafil. A neuropsychological battery and neurobehavioral symptom questionnaires were administered at each study visit. RESULTS After a single dose of sildenafil, TBI subjects showed a significant increase in global CVR compared to healthy controls (P < 0.001, d = 0.9). Post-sildenafil CVR maps showed near-normalization of CVR in many regions where baseline CVR was low, predominantly within areas without structural abnormalities. Sildenafil was well tolerated. Clinical Global Impression (CGI) scale showed a trend toward clinical improvement while on sildenafil treatment. FINDINGS Single-dose sildenafil improves regional CVR deficits in chronic TBI patients. CVR and ΔCVR are potential predictive and pharmacodynamic biomarkers of PDE5 inhibitor therapy for TCVI. Sildenafil is a potential therapy for TCVI.
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Affiliation(s)
- Kimbra Kenney
- Department of NeurologyUniformed Services University of the Health SciencesBethesdaMaryland
| | - Franck Amyot
- Department of NeurologyUniformed Services University of the Health SciencesBethesdaMaryland
| | - Carol Moore
- Department of NeurologyUniformed Services University of the Health SciencesBethesdaMaryland
| | - Margalit Haber
- Department of NeurologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | | | - Christian Shenouda
- Department of Physical Medicine and RehabilitationNational Institutes of Health Clinical CenterBethesdaMaryland
| | - Erika Silverman
- Department of NeurologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Yunhua Gong
- Department of NeurologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
| | - Bao‐ Xi Qu
- Department of NeurologyUniformed Services University of the Health SciencesBethesdaMaryland
| | - Leah Harburg
- Department of NeurologyUniformed Services University of the Health SciencesBethesdaMaryland
| | - Eric M. Wassermann
- Behavioral Neurology UnitNational Institute of Neurological Diseases and StrokeNational Institutes of HealthBethesdaMaryland
| | | | - Ramon Diaz‐Arrastia
- Department of NeurologyUniversity of Pennsylvania Perelman School of MedicinePhiladelphiaPennsylvania
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Boedtkjer E. Acid-base regulation and sensing: Accelerators and brakes in metabolic regulation of cerebrovascular tone. J Cereb Blood Flow Metab 2018; 38:588-602. [PMID: 28984162 PMCID: PMC5888856 DOI: 10.1177/0271678x17733868] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 08/10/2017] [Accepted: 09/06/2017] [Indexed: 12/29/2022]
Abstract
Metabolic regulation of cerebrovascular tone directs blood flow to areas of increased neuronal activity and during disease states partially compensates for insufficient perfusion by enhancing blood flow in collateral blood vessels. Acid-base disturbances frequently occur as result of enhanced metabolism or insufficient blood supply, but despite definitive evidence that acid-base disturbances alter arterial tone, effects of individual acid-base equivalents and the underlying signaling mechanisms are still being debated. H+ is an important intra- and extracellular messenger that modifies cerebrovascular tone. In addition, low extracellular [HCO3-] promotes cerebrovascular contraction through an endothelium-dependent mechanism. CO2 alters arterial tone development via changes in intra- and extracellular pH but it is still controversial whether CO2 also has direct vasomotor effects. Vasocontractile responses to low extracellular [HCO3-] and acute CO2-induced decreases in intracellular pH can counteract H+-mediated vasorelaxation during metabolic and respiratory acidosis, respectively, and may thereby reduce the risk of capillary damage and cerebral edema that could be consequences of unopposed vasodilation. In this review, the signaling mechanisms for acid-base equivalents in cerebral arteries and the mechanisms of intracellular pH control in the arterial wall are discussed in the context of metabolic regulation of cerebrovascular tone and local perfusion.
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Affiliation(s)
- Ebbe Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Chronic Hippocampal Expression of Notch Intracellular Domain Induces Vascular Thickening, Reduces Glucose Availability, and Exacerbates Spatial Memory Deficits in a Rat Model of Early Alzheimer. Mol Neurobiol 2018; 55:8637-8650. [PMID: 29582397 DOI: 10.1007/s12035-018-1002-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 03/07/2018] [Indexed: 02/07/2023]
Abstract
The specific roles of Notch in progressive adulthood neurodegenerative disorders have begun to be unraveled in recent years. A number of independent studies have shown significant increases of Notch expression in brains from patients at later stages of sporadic Alzheimer's disease (AD). However, the impact of Notch canonical signaling activation in the pathophysiology of AD is still elusive. To further investigate this issue, 2-month-old wild-type (WT) and hemizygous McGill-R-Thy1-APP rats (Tg(+/-)) were injected in CA1 with lentiviral particles (LVP) expressing the transcriptionally active fragment of Notch, known as Notch Intracellular Domain (NICD), (LVP-NICD), or control lentivirus particles (LVP-C). The Tg(+/-) rat model captures presymptomatic aspects of the AD pathology, including intraneuronal amyloid beta (Aβ) accumulation and early cognitive deficits. Seven months after LVP administration, Morris water maze test was performed, and brains isolated for biochemical and histological analysis. Our results showed a learning impairment and a worsening of spatial memory in LVP-NICD- as compared to LVP-C-injected Tg(+/-) rats. In addition, immuno histochemistry, ELISA multiplex, Western blot, RT-qPCR, and 1H-NMR spectrometry of cerebrospinal fluid (CSF) indicated that chronic expression of NICD promoted hippocampal vessel thickening with accumulation of Aβ in brain microvasculature, alteration of blood-brain barrier (BBB) permeability, and a decrease of CSF glucose levels. These findings suggest that, in the presence of early Aβ pathology, expression of NICD may contribute to the development of microvascular abnormalities, altering glucose transport at the BBB with impact on early decline of spatial learning and memory.
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Amyot F, Kenney K, Moore C, Haber M, Turtzo LC, Shenouda C, Silverman E, Gong Y, Qu BX, Harburg L, Lu HY, Wassermann EM, Diaz-Arrastia R. Imaging of Cerebrovascular Function in Chronic Traumatic Brain Injury. J Neurotrauma 2018; 35:1116-1123. [PMID: 29065769 DOI: 10.1089/neu.2017.5114] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Traumatic cerebrovascular injury (TCVI) is a common pathologic mechanism of traumatic brain injury (TBI) and presents an attractive target for intervention. The aims of this study were to assess cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) using magnetic resonance imaging (MRI) to assess their value as biomarkers of TCVI in chronic TBI, characterize the spatial distribution of TCVI, and assess the relationships between each biomarker and neuropsychological and clinical assessments. Forty-two subjects (27 chronic TBI, 15 age- and gender-matched healthy volunteers) were studied cross-sectionally. CBF was measured by arterial spin labeling and CVR by assessing the MRI-blood oxygen level-dependent signal with hypercapnia challenge. A focused neuropsychological battery adapted from the TBI Common Data Elements and neurobehavioral symptom questionnaires were administered at the time of the imaging session. Chronic TBI subjects showed a significant reduction in mean global, gray matter (GM), and white matter (WM) CVR, compared with healthy volunteers (p < 0.001). Mean GM CVR had the greatest effect size (Cohen's d = 0.9). CVR maps in chronic TBI subjects showed patchy, multifocal CVR deficits. CBF discriminated poorly between TBI subjects and healthy volunteers and did not correlate with CVR. Mean global CVR correlated best with chronic neurobehavioral symptoms among TBI subjects. Global, GM, and WM CVR are reliable and potentially useful biomarkers of TCVI in the chronic stage after moderate-to-severe TBI. CBF is less useful as biomarker of TCVI. CVR correlates best with chronic TBI symptoms. CVR has potential as a predictive and pharmacodynamic biomarker for interventions targeting TCVI.
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Affiliation(s)
- Franck Amyot
- 1 Department of Neurology, Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Kimbra Kenney
- 1 Department of Neurology, Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Carol Moore
- 1 Department of Neurology, Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Margalit Haber
- 2 Department of Neurology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - L Christine Turtzo
- 3 Center for Neuroscience and Regenerative Medicine, National Institute of Neurological Disorder and Stroke, National Institutes of Health , Bethesda, Maryland
| | - Christian Shenouda
- 3 Center for Neuroscience and Regenerative Medicine, National Institute of Neurological Disorder and Stroke, National Institutes of Health , Bethesda, Maryland
| | - Erika Silverman
- 2 Department of Neurology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - Yunhua Gong
- 2 Department of Neurology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
| | - Bao-Xi Qu
- 1 Department of Neurology, Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Leah Harburg
- 1 Department of Neurology, Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Hanzhang Y Lu
- 4 Department of Radiology and Radiological Science, Johns Hopkins University Baltimore , Maryland
| | - Eric M Wassermann
- 5 National Institute of Neurological Disorders and Stroke, National Institutes of Health , Bethesda, Maryland
| | - Ramon Diaz-Arrastia
- 2 Department of Neurology, University of Pennsylvania Perelman School of Medicine , Philadelphia, Pennsylvania
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Oboshi Y, Kikuchi M, Terada T, Yoshikawa E, Bunai T, Ouchi Y. Alterations in Phase-Related Prefrontal Activation During Cognitive Tasks and Nicotinic α4β2 Receptor Availability in Alzheimer's Disease. J Alzheimers Dis 2018; 53:817-30. [PMID: 27258412 DOI: 10.3233/jad-151165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Evidence shows that the cholinergic system plays an important role in regulating working memory and that working memory-related prefrontal activation decreases with age and neuronal degeneration, such as Alzheimer's disease (AD). However, the relation between attention-related α4β2 nicotinic cholinergic function and task-induced prefrontal activation especially time course-related activation remains to be explored. OBJECTIVE We aimed to elucidate the relationship between changes in task-induced oxy-hemoglobin concentration (cerebral blood flow, CBF) in the prefrontal cortex and the availability of α4β2 nicotinic receptors in the brain of AD patients in light of their task performance. METHODS Eleven mild-to-moderate AD patients and eleven normal elderly subjects underwent the near-infrared spectroscopy during easy and difficult working memory tasks for estimating prefrontal CBF changes and positron emission tomography with the α4β2 tracer [18F]2FA-85380 ([18F]2FA) for measuring the α4β2 nicotinic receptor binding. RESULTS Significant correlations between mean oxy-hemoglobin concentration in the channels with significant [group] main effects and prefrontal [18F]2FA binding were observed during the early easy task period in the normal group and during the late difficult task in the AD group. In addition, those prefrontal CBF responses were significantly correlated with not correct performance but the execution time to spend. CONCLUSION The α4β2 nicotinic acetylcholine receptors in the prefrontal cortex play an important role in increasing prefrontal activation when attending to novel stimuli, irrespective of the accuracy of the outcome. A delay in the cholinergic-induced increase in prefrontal activation in AD patients might explain their delayed responses in the cognitive task.
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Affiliation(s)
- Yumi Oboshi
- Department of Biofunctional Imaging, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Mitsuru Kikuchi
- Research Center for Child Mental Development, Kanazawa University, Kanazawa, Japan
| | - Tatsuhiro Terada
- Department of Biofunctional Imaging, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Japan.,Department of Neurology, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, Japan
| | - Etsuji Yoshikawa
- Central Research Laboratory, Hamamatsu Photonics K.K., Hamamatsu, Japan
| | - Tomoyasu Bunai
- Department of Biofunctional Imaging, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Yasuomi Ouchi
- Department of Biofunctional Imaging, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Thormodsson FR, Olafsson IH, Vilhjalmsson DT. Preparation and Culturing of Human Primary Vascular Cells. Methods Mol Biol 2018; 1779:355-369. [PMID: 29886543 DOI: 10.1007/978-1-4939-7816-8_21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cerebral amyloid angiopathy (CAA) results from amyloid accumulation within arteries of the cerebral cortex and leptomeninges. This condition is age-related, especially prevalent in Alzheimer's disease (AD), and the main feature of certain hereditary disorders (i.e., HCHWA-I). The vascular smooth muscle cells (VSMCs) appear to play a vital role in the development of CAA, which makes them well suited as an experimental model to study the disease and screen for possible remedies. We describe two different methods for isolating and culturing human VSMCs: First, using the human umbilical cord as an easy source of robust cells, and secondly, using brain tissue that provides the proper cerebral VSMCs, but is more problematic to work with. The umbilical cord also provides human umbilical vascular endothelial cells (HUVEC), useful primary cells for vascular research. Finally, the maintenance, preservation, and characterization of the isolated vascular cells are described.
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Glial Cell Calcium Signaling Mediates Capillary Regulation of Blood Flow in the Retina. J Neurosci 2017; 36:9435-45. [PMID: 27605617 DOI: 10.1523/jneurosci.1782-16.2016] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Accepted: 07/26/2016] [Indexed: 01/27/2023] Open
Abstract
UNLABELLED The brain is critically dependent on the regulation of blood flow to nourish active neurons. One widely held hypothesis of blood flow regulation holds that active neurons stimulate Ca(2+) increases in glial cells, triggering glial release of vasodilating agents. This hypothesis has been challenged, as arteriole dilation can occur in the absence of glial Ca(2+) signaling. We address this controversy by imaging glial Ca(2+) signaling and vessel dilation in the mouse retina. We find that sensory stimulation results in Ca(2+) increases in the glial endfeet contacting capillaries, but not arterioles, and that capillary dilations often follow spontaneous Ca(2+) signaling. In IP3R2(-/-) mice, where glial Ca(2+) signaling is reduced, light-evoked capillary, but not arteriole, dilation is abolished. The results show that, independent of arterioles, capillaries actively dilate and regulate blood flow. Furthermore, the results demonstrate that glial Ca(2+) signaling regulates capillary but not arteriole blood flow. SIGNIFICANCE STATEMENT We show that a Ca(2+)-dependent glial cell signaling mechanism is responsible for regulating capillary but not arteriole diameter. This finding resolves a long-standing controversy regarding the role of glial cells in regulating blood flow, demonstrating that glial Ca(2+) signaling is both necessary and sufficient to dilate capillaries. While the relative contributions of capillaries and arterioles to blood flow regulation remain unclear, elucidating the mechanisms that regulate capillary blood flow may ultimately lead to the development of therapies for treating diseases where blood flow regulation is disrupted, including Alzheimer's disease, stroke, and diabetic retinopathy. This finding may also aid in revealing the underlying neuronal activity that generates BOLD fMRI signals.
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Tarantini S, Fulop GA, Kiss T, Farkas E, Zölei-Szénási D, Galvan V, Toth P, Csiszar A, Ungvari Z, Yabluchanskiy A. Demonstration of impaired neurovascular coupling responses in TG2576 mouse model of Alzheimer's disease using functional laser speckle contrast imaging. GeroScience 2017; 39:465-473. [PMID: 28578467 PMCID: PMC5636768 DOI: 10.1007/s11357-017-9980-z] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 05/23/2017] [Indexed: 01/28/2023] Open
Abstract
Increasing evidence from epidemiological, clinical, and experimental studies indicates that cerebromicrovascular dysfunction and microcirculatory damage play critical roles in the pathogenesis of many types of dementia in the elderly, including both vascular cognitive impairment (VCI) and Alzheimer's disease. Vascular contributions to cognitive impairment and dementia (VCID) include impairment of neurovascular coupling responses/functional hyperemia ("neurovascular uncoupling"). Due to the growing interest in understanding and pharmacologically targeting pathophysiological mechanisms of VCID, there is an increasing need for sensitive, easy-to-establish methods to assess neurovascular coupling responses. Laser speckle contrast imaging (LSCI) is a technique that allows rapid and minimally invasive visualization of changes in regional cerebromicrovascular blood perfusion. This type of imaging technique combines high resolution and speed to provide great spatiotemporal accuracy to measure moment-to-moment changes in cerebral blood flow induced by neuronal activation. Here, we provide detailed protocols for the successful measurement in neurovascular coupling responses in anesthetized mice equipped with a thinned-skull cranial window using LSCI. This method can be used to evaluate the effects of anti-aging or anti-AD treatments on cerebromicrovascular health.
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Affiliation(s)
- Stefano Tarantini
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, Oklahoma, OK, 73104, USA
- Translational Geroscience Laboratory, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma, OK, USA
| | - Gabor A Fulop
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, Oklahoma, OK, 73104, USA
- Translational Geroscience Laboratory, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma, OK, USA
| | - Tamas Kiss
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, Oklahoma, OK, 73104, USA
- Translational Geroscience Laboratory, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma, OK, USA
- Faculty of Medicine & Faculty of Science and Informatics, Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Eszter Farkas
- Faculty of Medicine & Faculty of Science and Informatics, Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Dániel Zölei-Szénási
- Faculty of Medicine & Faculty of Science and Informatics, Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Veronica Galvan
- Department of Cellular and Integrative Physiology, Barshop Institute for Longevity and Aging Studies University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Peter Toth
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, Oklahoma, OK, 73104, USA
- Translational Geroscience Laboratory, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma, OK, USA
- Department of Neurosurgery, University of Pecs, Pecs, Hungary
| | - Anna Csiszar
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, Oklahoma, OK, 73104, USA
- Translational Geroscience Laboratory, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma, OK, USA
| | - Zoltan Ungvari
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, Oklahoma, OK, 73104, USA
- Translational Geroscience Laboratory, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma, OK, USA
| | - Andriy Yabluchanskiy
- Reynolds Oklahoma Center on Aging, University of Oklahoma Health Sciences Center, 975 NE 10th Street, Oklahoma, OK, 73104, USA.
- Translational Geroscience Laboratory, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center, Oklahoma, OK, USA.
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Michalski D, Hofmann S, Pitsch R, Grosche J, Härtig W. Neurovascular Specifications in the Alzheimer-Like Brain of Mice Affected by Focal Cerebral Ischemia: Implications for Future Therapies. J Alzheimers Dis 2017; 59:655-674. [DOI: 10.3233/jad-170185] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
| | - Sarah Hofmann
- Paul Flechsig Institute for Brain Research, University of Leipzig, Leipzig, Germany
| | - Roman Pitsch
- Paul Flechsig Institute for Brain Research, University of Leipzig, Leipzig, Germany
| | | | - Wolfgang Härtig
- Paul Flechsig Institute for Brain Research, University of Leipzig, Leipzig, Germany
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