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Rizko JM, Beishon LC, Panerai RB, Marmarelis VZ. Cognitive activity significantly affects the dynamic cerebral autoregulation, but not the dynamic vasoreactivity, in healthy adults. Front Physiol 2024; 15:1350832. [PMID: 39314625 PMCID: PMC11417032 DOI: 10.3389/fphys.2024.1350832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 08/22/2024] [Indexed: 09/25/2024] Open
Abstract
Introduction Neurovascular coupling (NVC) is an important mechanism for the regulation of cerebral perfusion during intensive cognitive activity. Thus, it should be examined in terms of its effects on the regulation dynamics of cerebral perfusion and its possible alterations during cognitive impairment. The dynamic dependence of continuous changes in cerebral blood velocity (CBv), which can be measured noninvasively using transcranial Doppler upon fluctuations in arterial blood pressure (ABP) and CO2 tension, using end-tidal CO2 (EtCO2) as a proxy, can be quantified via data-based dynamic modeling to yield insights into two key regulatory mechanisms: the dynamic cerebral autoregulation (dCA) and dynamic vasomotor reactivity (DVR), respectively. Methods Using the Laguerre Expansion Technique (LET), this study extracted such models from data in supine resting vs cognitively active conditions (during attention, fluency, and memory tasks from the Addenbrooke's Cognitive Examination III, ACE-III) to elucidate possible changes in dCA and DVR due to cognitive stimulation of NVC. Healthy volunteers (n = 39) were recruited at the University of Leicester and continuous measurements of CBv, ABP, and EtCO2 were recorded. Results Modeling analysis of the dynamic ABP-to-CBv and CO2-to-CBv relationships showed significant changes in dCA, but not DVR, under cognitively active conditions compared to resting state. Discussion Interpretation of these changes through Principal Dynamic Mode (PDM) analysis is discussed in terms of possible associations between stronger NVC stimulation during cognitive tasks and enhanced sympathetic activation.
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Affiliation(s)
- Jasmin M. Rizko
- A. E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Lucy C. Beishon
- Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- Leicester Biomedical Research Centre, National Institute for Health Research, Leicester, United Kingdom
| | - Ronney B. Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- Leicester Biomedical Research Centre, National Institute for Health Research, Leicester, United Kingdom
| | - Vasilis Z. Marmarelis
- A. E. Mann Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
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Gallego-Durán R, Hadjihambi A, Ampuero J, Rose CF, Jalan R, Romero-Gómez M. Ammonia-induced stress response in liver disease progression and hepatic encephalopathy. Nat Rev Gastroenterol Hepatol 2024:10.1038/s41575-024-00970-9. [PMID: 39251708 DOI: 10.1038/s41575-024-00970-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/24/2024] [Indexed: 09/11/2024]
Abstract
Ammonia levels are orchestrated by a series of complex interrelated pathways in which the urea cycle has a central role. Liver dysfunction leads to an accumulation of ammonia, which is toxic and is strongly associated with disruption of potassium homeostasis, mitochondrial dysfunction, oxidative stress, inflammation, hypoxaemia and dysregulation of neurotransmission. Hyperammonaemia is a hallmark of hepatic encephalopathy and has been strongly associated with liver-related outcomes in patients with cirrhosis and liver failure. In addition to the established role of ammonia as a neurotoxin in the pathogenesis of hepatic encephalopathy, an increasing number of studies suggest that it can lead to hepatic fibrosis progression, sarcopenia, immune dysfunction and cancer. However, elevated systemic ammonia levels are uncommon in patients with metabolic dysfunction-associated steatotic liver disease. A clear causal relationship between ammonia-induced immune dysfunction and risk of infection has not yet been definitively proven. In this Review, we discuss the mechanisms by which ammonia produces its diverse deleterious effects and their clinical relevance in liver diseases, the importance of measuring ammonia levels for the diagnosis of hepatic encephalopathy, the prognosis of patients with cirrhosis and liver failure, and how our knowledge of inter-organ ammonia metabolism is leading to the development of novel therapeutic approaches.
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Affiliation(s)
- Rocío Gallego-Durán
- UCM Digestive Diseases, Virgen del Rocío University Hospital. Instituto de Biomedicina de Sevilla (HUVR/CSIC/US), Department of Medicine, University of Seville, Seville, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Madrid, Spain
| | - Anna Hadjihambi
- The Roger Williams Institute of Hepatology, Foundation for Liver Research, London, UK
- Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Javier Ampuero
- UCM Digestive Diseases, Virgen del Rocío University Hospital. Instituto de Biomedicina de Sevilla (HUVR/CSIC/US), Department of Medicine, University of Seville, Seville, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Madrid, Spain
| | - Christopher F Rose
- Hepato-Neuro Laboratory, CRCHUM, Université de Montréal, Montreal, Canada
| | - Rajiv Jalan
- Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, London, UK
- European Foundation for the Study of Chronic Liver Failure, Barcelona, Spain
| | - Manuel Romero-Gómez
- UCM Digestive Diseases, Virgen del Rocío University Hospital. Instituto de Biomedicina de Sevilla (HUVR/CSIC/US), Department of Medicine, University of Seville, Seville, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Madrid, Spain.
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Wang Y, Feng Y, Pan Q, Qu Q, Wen B, Pang F, Xu J. Fronto-parietal activity changes associated with changes in working memory load: Evidence from simultaneous electroencephalography and functional near-infrared spectroscopy analysis. Eur J Neurosci 2024. [PMID: 39223860 DOI: 10.1111/ejn.16478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 06/29/2024] [Accepted: 07/10/2024] [Indexed: 09/04/2024]
Abstract
Working memory (WM) involves the capacity to maintain and manipulate information over short periods. Previous research has suggested that fronto-parietal activities play a crucial role in WM. However, there remains no agreement on the effect of working memory load (WML) on neural activities and haemodynamic responses. Here, our study seeks to examine the effect of WML through simultaneous electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS). In this study, a delay change detection task was conducted on 23 healthy volunteers. The task included three levels: one item, three items and five items. The EEG and fNIRS were simultaneously recorded during the task. Neural activities and haemodynamic responses at prefrontal and parietal regions were analysed using time-frequency analysis and weighted phase-lag index (wPLI). We observed a significant enhancement in prefrontal and parietal β suppression as WML increased. Furthermore, as WML increased, there was a notable enhancement in fronto-parietal connectivity (FPC), as evidenced by both EEG and fNIRS. Correlation analysis indicated that as WML increased, there was a potential for enhancement of neurovascular coupling (NVC) of FPC.
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Affiliation(s)
- Yu Wang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, P. R. China
- Sichuan Digital Economy Industry Development Research Institute, Chengdu, Sichuan, P. R. China
| | - Yihang Feng
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, P. R. China
| | - Qi Pan
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, P. R. China
| | - Qiumin Qu
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, P. R. China
| | - Bin Wen
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, P. R. China
| | - Fangning Pang
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, P. R. China
| | - Jin Xu
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi, P. R. China
- Sichuan Digital Economy Industry Development Research Institute, Chengdu, Sichuan, P. R. China
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Uekawa K, Anfray A, Ahn SJ, Casey N, Seo J, Zhou P, Iadecola C, Park L. tPA supplementation preserves neurovascular and cognitive function in Tg2576 mice. Alzheimers Dement 2024; 20:4572-4582. [PMID: 38899570 PMCID: PMC11247712 DOI: 10.1002/alz.13878] [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: 02/16/2024] [Revised: 04/17/2024] [Accepted: 04/17/2024] [Indexed: 06/21/2024]
Abstract
INTRODUCTION Amyloid beta (Aβ) impairs the cerebral blood flow (CBF) increase induced by neural activity (functional hyperemia). Tissue plasminogen activator (tPA) is required for functional hyperemia, and in mouse models of Aβ accumulation tPA deficiency contributes to neurovascular and cognitive impairment. However, it remains unknown if tPA supplementation can rescue Aβ-induced neurovascular and cognitive dysfunction. METHODS Tg2576 mice and wild-type littermates received intranasal tPA (0.8 mg/kg/day) or vehicle 5 days a week starting at 11 to 12 months of age and were assessed 3 months later. RESULTS Treatment of Tg2576 mice with tPA restored resting CBF, prevented the attenuation in functional hyperemia, and improved nesting behavior. These effects were associated with reduced cerebral atrophy and cerebral amyloid angiopathy, but not parenchymal amyloid. DISCUSSION These findings highlight the key role of tPA deficiency in the neurovascular and cognitive dysfunction associated with amyloid pathology, and suggest potential therapeutic strategies involving tPA reconstitution. HIGHLIGHTS Amyloid beta (Aβ) induces neurovascular dysfunction and impairs the increase of cerebral blood flow induced by neural activity (functional hyperemia). Tissue plasminogen activator (tPA) deficiency contributes to the neurovascular and cognitive dysfunction caused by Aβ. In mice with florid amyloid pathology intranasal administration of tPA rescues the neurovascular and cognitive dysfunction and reduces brain atrophy and cerebral amyloid angiopathy. tPA deficiency plays a crucial role in neurovascular and cognitive dysfunction induced by Aβ and tPA reconstitution may be of therapeutic value.
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Affiliation(s)
- Ken Uekawa
- Feil Family Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNew YorkUSA
| | - Antoine Anfray
- Feil Family Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNew YorkUSA
| | - Sung Ji Ahn
- Feil Family Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNew YorkUSA
| | - Nicole Casey
- Feil Family Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNew YorkUSA
| | - James Seo
- Feil Family Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNew YorkUSA
| | - Ping Zhou
- Feil Family Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNew YorkUSA
| | - Costantino Iadecola
- Feil Family Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNew YorkUSA
| | - Laibaik Park
- Feil Family Brain and Mind Research Institute, Weill Cornell MedicineNew YorkNew YorkUSA
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Theparambil SM, Begum G, Rose CR. pH regulating mechanisms of astrocytes: A critical component in physiology and disease of the brain. Cell Calcium 2024; 120:102882. [PMID: 38631162 PMCID: PMC11423562 DOI: 10.1016/j.ceca.2024.102882] [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: 03/05/2024] [Revised: 03/28/2024] [Accepted: 03/28/2024] [Indexed: 04/19/2024]
Abstract
Strict homeostatic control of pH in both intra- and extracellular compartments of the brain is fundamentally important, primarily due to the profound impact of free protons ([H+]) on neuronal activity and overall brain function. Astrocytes, crucial players in the homeostasis of various ions in the brain, actively regulate their intracellular [H+] (pHi) through multiple membrane transporters and carbonic anhydrases. The activation of astroglial pHi regulating mechanisms also leads to corresponding alterations in the acid-base status of the extracellular fluid. Notably, astrocyte pH regulators are modulated by various neuronal signals, suggesting their pivotal role in regulating brain acid-base balance in both health and disease. This review presents the mechanisms involved in pH regulation in astrocytes and discusses their potential impact on extracellular pH under physiological conditions and in brain disorders. Targeting astrocytic pH regulatory mechanisms represents a promising therapeutic approach for modulating brain acid-base balance in diseases, offering a potential critical contribution to neuroprotection.
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Affiliation(s)
- Shefeeq M Theparambil
- Faculty of Health and Medicine, Department of Biomedical and Life Sciences, Lancaster University, Lancaster, LA1 4YW, Lancaster, UK.
| | - Gulnaz Begum
- Department of Neurology, The Pittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh, Pittsburgh, PA, USA
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Düsseldorf, 40225, Düsseldorf, Germany
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Ruff CF, Juarez Anaya F, Dienel SJ, Rakymzhan A, Altamirano-Espinoza A, Couey JJ, Fukuda M, Watson AM, Su A, Fish KN, Rubio ME, Hooks BM, Ross SE, Vazquez AL. Long-range inhibitory neurons mediate cortical neurovascular coupling. Cell Rep 2024; 43:113970. [PMID: 38512868 PMCID: PMC11168451 DOI: 10.1016/j.celrep.2024.113970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/29/2023] [Accepted: 02/29/2024] [Indexed: 03/23/2024] Open
Abstract
To meet the high energy demands of brain function, cerebral blood flow (CBF) parallels changes in neuronal activity by a mechanism known as neurovascular coupling (NVC). However, which neurons play a role in mediating NVC is not well understood. Here, we identify in mice and humans a specific population of cortical GABAergic neurons that co-express neuronal nitric oxide synthase and tachykinin receptor 1 (Tacr1). Through whole-tissue clearing, we demonstrate that Tacr1 neurons extend local and long-range projections across functionally connected cortical areas. We show that whisker stimulation elicited Tacr1 neuron activity in the barrel cortex through feedforward excitatory pathways. Additionally, through optogenetic experiments, we demonstrate that Tacr1 neurons are instrumental in mediating CBF through the relaxation of mural cells in a similar fashion to whisker stimulation. Finally, by electron microscopy, we observe that Tacr1 processes contact astrocytic endfeet. These findings suggest that Tacr1 neurons integrate cortical activity to mediate NVC.
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Affiliation(s)
- Catherine F Ruff
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Samuel J Dienel
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Adiya Rakymzhan
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Jonathan J Couey
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mitsuhiro Fukuda
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alan M Watson
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, USA
| | - Aihua Su
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kenneth N Fish
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Maria E Rubio
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bryan M Hooks
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sarah E Ross
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Alberto L Vazquez
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA.
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Vasilkovska T, Salajeghe S, Vanreusel V, Van Audekerke J, Verschuuren M, Hirschler L, Warnking J, Pintelon I, Pustina D, Cachope R, Mrzljak L, Muñoz-Sanjuan I, Barbier EL, De Vos WH, Van der Linden A, Verhoye M. Longitudinal alterations in brain perfusion and vascular reactivity in the zQ175DN mouse model of Huntington's disease. J Biomed Sci 2024; 31:37. [PMID: 38627751 PMCID: PMC11022401 DOI: 10.1186/s12929-024-01028-3] [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: 01/05/2024] [Accepted: 04/08/2024] [Indexed: 04/19/2024] Open
Abstract
BACKGROUND Huntington's disease (HD) is marked by a CAG-repeat expansion in the huntingtin gene that causes neuronal dysfunction and loss, affecting mainly the striatum and the cortex. Alterations in the neurovascular coupling system have been shown to lead to dysregulated energy supply to brain regions in several neurological diseases, including HD, which could potentially trigger the process of neurodegeneration. In particular, it has been observed in cross-sectional human HD studies that vascular alterations are associated to impaired cerebral blood flow (CBF). To assess whether whole-brain changes in CBF are present and follow a pattern of progression, we investigated both resting-state brain perfusion and vascular reactivity longitudinally in the zQ175DN mouse model of HD. METHODS Using pseudo-continuous arterial spin labelling (pCASL) MRI in the zQ175DN model of HD and age-matched wild-type (WT) mice, we assessed whole-brain, resting-state perfusion at 3, 6 and 9 and 13 months of age, and assessed hypercapnia-induced cerebrovascular reactivity (CVR), at 4.5, 6, 9 and 15 months of age. RESULTS We found increased perfusion in cortical regions of zQ175DN HET mice at 3 months of age, and a reduction of this anomaly at 6 and 9 months, ages at which behavioural deficits have been reported. On the other hand, under hypercapnia, CBF was reduced in zQ175DN HET mice as compared to the WT: for multiple brain regions at 6 months of age, for only somatosensory and retrosplenial cortices at 9 months of age, and brain-wide by 15 months. CVR impairments in cortical regions, the thalamus and globus pallidus were observed in zQ175DN HET mice at 9 months, with whole brain reactivity diminished at 15 months of age. Interestingly, blood vessel density was increased in the motor cortex at 3 months, while average vessel length was reduced in the lateral portion of the caudate putamen at 6 months of age. CONCLUSION Our findings reveal early cortical resting-state hyperperfusion and impaired CVR at ages that present motor anomalies in this HD model, suggesting that further characterization of brain perfusion alterations in animal models is warranted as a potential therapeutic target in HD.
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Affiliation(s)
- Tamara Vasilkovska
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium.
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium.
| | - Somaie Salajeghe
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Verdi Vanreusel
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Johan Van Audekerke
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Marlies Verschuuren
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Lydiane Hirschler
- C.J. Gorter MRI Center, Leiden University Medical Center, Leiden, the Netherlands
| | - Jan Warnking
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble, France
| | - Isabel Pintelon
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Dorian Pustina
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
| | - Roger Cachope
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
| | - Ladislav Mrzljak
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
- Present Address: Takeda Pharmaceuticals, Cambridge, MA, USA
| | - Ignacio Muñoz-Sanjuan
- CHDI Management, Inc., the company that manages the scientific activities of CHDI Foundation, Inc, Princeton, NJ, USA
- Present Address: Cajal Neuroscience Inc, Seattle, WA, USA
| | - Emmanuel L Barbier
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble, France
| | - Winnok H De Vos
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
- Laboratory of Cell Biology and Histology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- Antwerp Centre for Advanced Microscopy, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
| | - Annemie Van der Linden
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
| | - Marleen Verhoye
- Bio-Imaging Lab, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Antwerp, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp, Belgium
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Dempsey S, Argus F, Maso Talou GD, Safaei S. An interaction graph approach to gain new insights into mechanisms that modulate cerebrovascular tone. Commun Biol 2024; 7:404. [PMID: 38570584 PMCID: PMC10991376 DOI: 10.1038/s42003-024-06064-1] [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: 09/04/2023] [Accepted: 03/18/2024] [Indexed: 04/05/2024] Open
Abstract
Mechanisms to modulate cerebrovascular tone are numerous, interconnected, and spatially dependent, increasing the complexity of experimental study design, interpretation of action-effect pathways, and mechanistic modelling. This difficulty is exacerbated when there is an incomplete understanding of these pathways. We propose interaction graphs to break down this complexity, while still maintaining a holistic view of mechanisms to modulate cerebrovascular tone. These graphs highlight the competing processes of neurovascular coupling, cerebral autoregulation, and cerebral reactivity. Subsequent analysis of these interaction graphs provides new insights and suggest potential directions for research on neurovascular coupling, modelling, and dementia.
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Affiliation(s)
- Sergio Dempsey
- Auckland Bioengineering Institute, University of Auckland, Level 6/70 Symonds Street, Grafton, Auckland, 1010, New Zealand.
| | - Finbar Argus
- Auckland Bioengineering Institute, University of Auckland, Level 6/70 Symonds Street, Grafton, Auckland, 1010, New Zealand
| | - Gonzalo Daniel Maso Talou
- Auckland Bioengineering Institute, University of Auckland, Level 6/70 Symonds Street, Grafton, Auckland, 1010, New Zealand
| | - Soroush Safaei
- Auckland Bioengineering Institute, University of Auckland, Level 6/70 Symonds Street, Grafton, Auckland, 1010, New Zealand
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Hu Y, Zhang F, Ikonomovic M, Yang T. The Role of NRF2 in Cerebrovascular Protection: Implications for Vascular Cognitive Impairment and Dementia (VCID). Int J Mol Sci 2024; 25:3833. [PMID: 38612642 PMCID: PMC11012233 DOI: 10.3390/ijms25073833] [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: 02/03/2024] [Revised: 03/20/2024] [Accepted: 03/22/2024] [Indexed: 04/14/2024] Open
Abstract
Vascular cognitive impairment and dementia (VCID) represents a broad spectrum of cognitive decline secondary to cerebral vascular aging and injury. It is the second most common type of dementia, and the prevalence continues to increase. Nuclear factor erythroid 2-related factor 2 (NRF2) is enriched in the cerebral vasculature and has diverse roles in metabolic balance, mitochondrial stabilization, redox balance, and anti-inflammation. In this review, we first briefly introduce cerebrovascular aging in VCID and the NRF2 pathway. We then extensively discuss the effects of NRF2 activation in cerebrovascular components such as endothelial cells, vascular smooth muscle cells, pericytes, and perivascular macrophages. Finally, we summarize the clinical potential of NRF2 activators in VCID.
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Affiliation(s)
- Yizhou Hu
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15216, USA; (Y.H.); (F.Z.); (M.I.)
- Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh, Pittsburgh, PA 15216, USA
- Department of Internal Medicine, University of Pittsburgh Medical Center (UPMC) McKeesport, McKeesport, PA 15132, USA
| | - Feng Zhang
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15216, USA; (Y.H.); (F.Z.); (M.I.)
- Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh, Pittsburgh, PA 15216, USA
| | - Milos Ikonomovic
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15216, USA; (Y.H.); (F.Z.); (M.I.)
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA 15216, USA
- Geriatric Research Education and Clinical Center, VA Pittsburgh Healthcare System, Pittsburgh, PA 15240, USA
| | - Tuo Yang
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15216, USA; (Y.H.); (F.Z.); (M.I.)
- Pittsburgh Institute of Brain Disorders and Recovery, University of Pittsburgh, Pittsburgh, PA 15216, USA
- Department of Internal Medicine, University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA 15216, USA
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Uchida S, Kagitani F. Influence of age on nicotinic cholinergic regulation of blood flow in rat's olfactory bulb and neocortex. J Physiol Sci 2024; 74:18. [PMID: 38491428 PMCID: PMC10941616 DOI: 10.1186/s12576-024-00913-8] [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: 02/23/2024] [Accepted: 03/06/2024] [Indexed: 03/18/2024]
Abstract
The olfactory bulb receives cholinergic basal forebrain inputs as does the neocortex. With a focus on nicotinic acetylcholine receptors (nAChRs), this review article provides an overview and discussion of the following findings: (1) the nAChRs-mediated regulation of regional blood flow in the neocortex and olfactory bulb, (2) the nAChR subtypes that mediate their responses, and (3) their activity in old rats. The activation of the α4β2-like subtype of nAChRs produces vasodilation in the neocortex, and potentiates olfactory bulb vasodilation induced by olfactory stimulation. The nAChR activity producing neocortical vasodilation was similarly maintained in 2-year-old rats as in adult rats, but was clearly reduced in 3-year-old rats. In contrast, nAChR activity in the olfactory bulb was reduced already in 2-year-old rats. Thus, age-related impairment of α4β2-like nAChR function may occur earlier in the olfactory bulb than in the neocortex. Given the findings, the vasodilation induced by α4β2-like nAChR activation may be beneficial for neuroprotection in the neocortex and the olfactory bulb.
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Affiliation(s)
- Sae Uchida
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute for Geriatrics and Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo, 173-0015, Japan.
| | - Fusako Kagitani
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute for Geriatrics and Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo, 173-0015, Japan
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Owens CD, Bonin Pinto C, Detwiler S, Olay L, Pinaffi-Langley ACDC, Mukli P, Peterfi A, Szarvas Z, James JA, Galvan V, Tarantini S, Csiszar A, Ungvari Z, Kirkpatrick AC, Prodan CI, Yabluchanskiy A. Neurovascular coupling impairment as a mechanism for cognitive deficits in COVID-19. Brain Commun 2024; 6:fcae080. [PMID: 38495306 PMCID: PMC10943572 DOI: 10.1093/braincomms/fcae080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 02/08/2024] [Accepted: 03/05/2024] [Indexed: 03/19/2024] Open
Abstract
Components that comprise our brain parenchymal and cerebrovascular structures provide a homeostatic environment for proper neuronal function to ensure normal cognition. Cerebral insults (e.g. ischaemia, microbleeds and infection) alter cellular structures and physiologic processes within the neurovascular unit and contribute to cognitive dysfunction. COVID-19 has posed significant complications during acute and convalescent stages in multiple organ systems, including the brain. Cognitive impairment is a prevalent complication in COVID-19 patients, irrespective of severity of acute SARS-CoV-2 infection. Moreover, overwhelming evidence from in vitro, preclinical and clinical studies has reported SARS-CoV-2-induced pathologies in components of the neurovascular unit that are associated with cognitive impairment. Neurovascular unit disruption alters the neurovascular coupling response, a critical mechanism that regulates cerebromicrovascular blood flow to meet the energetic demands of locally active neurons. Normal cognitive processing is achieved through the neurovascular coupling response and involves the coordinated action of brain parenchymal cells (i.e. neurons and glia) and cerebrovascular cell types (i.e. endothelia, smooth muscle cells and pericytes). However, current work on COVID-19-induced cognitive impairment has yet to investigate disruption of neurovascular coupling as a causal factor. Hence, in this review, we aim to describe SARS-CoV-2's effects on the neurovascular unit and how they can impact neurovascular coupling and contribute to cognitive decline in acute and convalescent stages of the disease. Additionally, we explore potential therapeutic interventions to mitigate COVID-19-induced cognitive impairment. Given the great impact of cognitive impairment associated with COVID-19 on both individuals and public health, the necessity for a coordinated effort from fundamental scientific research to clinical application becomes imperative. This integrated endeavour is crucial for mitigating the cognitive deficits induced by COVID-19 and its subsequent burden in this especially vulnerable population.
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Affiliation(s)
- Cameron D Owens
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Camila Bonin Pinto
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Sam Detwiler
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
| | - Lauren Olay
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
| | - Ana Clara da C Pinaffi-Langley
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
| | - Peter Mukli
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Departments of Public Health, Translational Medicine and Physiology, Semmelweis University, Budapest, 1089, Hungary
| | - Anna Peterfi
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Departments of Public Health, Translational Medicine and Physiology, Semmelweis University, Budapest, 1089, Hungary
| | - Zsofia Szarvas
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Departments of Public Health, Translational Medicine and Physiology, Semmelweis University, Budapest, 1089, Hungary
| | - Judith A James
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
- Arthritis & Clinical Immunology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
- Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Veronica Galvan
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA
| | - Stefano Tarantini
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Departments of Public Health, Translational Medicine and Physiology, Semmelweis University, Budapest, 1089, Hungary
- The Peggy and Charles Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Anna Csiszar
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Departments of Public Health, Translational Medicine and Physiology, Semmelweis University, Budapest, 1089, Hungary
| | - Zoltan Ungvari
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Departments of Public Health, Translational Medicine and Physiology, Semmelweis University, Budapest, 1089, Hungary
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Angelia C Kirkpatrick
- Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA
- Cardiovascular Section, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
| | - Calin I Prodan
- Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA
- Department of Neurology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Andriy Yabluchanskiy
- Oklahoma Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73117, USA
- Vascular Cognitive Impairment, Neurodegeneration and Healthy Brain Aging Program, Department of Neurosurgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- International Training Program in Geroscience, Doctoral School of Basic and Translational Medicine/Departments of Public Health, Translational Medicine and Physiology, Semmelweis University, Budapest, 1089, Hungary
- Department of Health Promotion Sciences, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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12
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Cerri DH, Albaugh DL, Walton LR, Katz B, Wang TW, Chao THH, Zhang W, Nonneman RJ, Jiang J, Lee SH, Etkin A, Hall CN, Stuber GD, Shih YYI. Distinct neurochemical influences on fMRI response polarity in the striatum. Nat Commun 2024; 15:1916. [PMID: 38429266 PMCID: PMC10907631 DOI: 10.1038/s41467-024-46088-z] [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: 03/30/2023] [Accepted: 02/13/2024] [Indexed: 03/03/2024] Open
Abstract
The striatum, known as the input nucleus of the basal ganglia, is extensively studied for its diverse behavioral roles. However, the relationship between its neuronal and vascular activity, vital for interpreting functional magnetic resonance imaging (fMRI) signals, has not received comprehensive examination within the striatum. Here, we demonstrate that optogenetic stimulation of dorsal striatal neurons or their afferents from various cortical and subcortical regions induces negative striatal fMRI responses in rats, manifesting as vasoconstriction. These responses occur even with heightened striatal neuronal activity, confirmed by electrophysiology and fiber-photometry. In parallel, midbrain dopaminergic neuron optogenetic modulation, coupled with electrochemical measurements, establishes a link between striatal vasodilation and dopamine release. Intriguingly, in vivo intra-striatal pharmacological manipulations during optogenetic stimulation highlight a critical role of opioidergic signaling in generating striatal vasoconstriction. This observation is substantiated by detecting striatal vasoconstriction in brain slices after synthetic opioid application. In humans, manipulations aimed at increasing striatal neuronal activity likewise elicit negative striatal fMRI responses. Our results emphasize the necessity of considering vasoactive neurotransmission alongside neuronal activity when interpreting fMRI signal.
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Affiliation(s)
- Domenic H Cerri
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Daniel L Albaugh
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Lindsay R Walton
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Brittany Katz
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tzu-Wen Wang
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tzu-Hao Harry Chao
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Weiting Zhang
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Randal J Nonneman
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jing Jiang
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Sung-Ho Lee
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Amit Etkin
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
- Alto Neuroscience, Los Altos, CA, USA
| | - Catherine N Hall
- Sussex Neuroscience, University of Sussex, Falmer, United Kingdom
- School of Psychology, University of Sussex, Falmer, United Kingdom
| | - Garret D Stuber
- Center for Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA, USA
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Yen-Yu Ian Shih
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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13
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Gonçalves JS, Marçal AL, Marques BS, Costa FD, Laranjinha J, Rocha BS, Lourenço CF. Dietary nitrate supplementation and cognitive health: the nitric oxide-dependent neurovascular coupling hypothesis. Biochem Soc Trans 2024; 52:279-289. [PMID: 38385536 DOI: 10.1042/bst20230491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 02/02/2024] [Accepted: 02/05/2024] [Indexed: 02/23/2024]
Abstract
Diet is currently recognized as a major modifiable agent of human health. In particular, dietary nitrate has been increasingly explored as a strategy to modulate different physiological mechanisms with demonstrated benefits in multiple organs, including gastrointestinal, cardiovascular, metabolic, and endocrine systems. An intriguing exception in this scenario has been the brain, for which the evidence of the nitrate benefits remains controversial. Upon consumption, nitrate can undergo sequential reduction reactions in vivo to produce nitric oxide (•NO), a ubiquitous paracrine messenger that supports multiple physiological events such as vasodilation and neuromodulation. In the brain, •NO plays a key role in neurovascular coupling, a fine process associated with the dynamic regulation of cerebral blood flow matching the metabolic needs of neurons and crucial for sustaining brain function. Neurovascular coupling dysregulation has been associated with neurodegeneration and cognitive dysfunction during different pathological conditions and aging. We discuss the potential biological action of nitrate on brain health, concerning the molecular mechanisms underpinning this association, particularly via modulation of •NO-dependent neurovascular coupling. The impact of nitrate supplementation on cognitive performance was scrutinized through preclinical and clinical data, suggesting that intervention length and the health condition of the participants are determinants of the outcome. Also, it stresses the need for multimodal quantitative studies relating cellular and mechanistic approaches to function coupled with behavior clinical outputs to understand whether a mechanistic relationship between dietary nitrate and cognitive health is operative in the brain. If proven, it supports the exciting hypothesis of cognitive enhancement via diet.
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Affiliation(s)
- João S Gonçalves
- Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga 3004-504 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Health Science Campus, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Ana L Marçal
- Faculty of Pharmacy, University of Coimbra, Health Science Campus, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Bárbara S Marques
- Faculty of Pharmacy, University of Coimbra, Health Science Campus, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Filipa D Costa
- Faculty of Pharmacy, University of Coimbra, Health Science Campus, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - João Laranjinha
- Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga 3004-504 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Health Science Campus, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Bárbara S Rocha
- Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga 3004-504 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Health Science Campus, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
| | - Cátia F Lourenço
- Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga 3004-504 Coimbra, Portugal
- Faculty of Pharmacy, University of Coimbra, Health Science Campus, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal
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14
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Djurich S, Secomb TW. Analysis of potassium ion diffusion from neurons to capillaries: Effects of astrocyte endfeet geometry. Eur J Neurosci 2024; 59:323-332. [PMID: 38123136 PMCID: PMC10872621 DOI: 10.1111/ejn.16232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 11/25/2023] [Accepted: 12/02/2023] [Indexed: 12/23/2023]
Abstract
Neurovascular coupling (NVC) refers to a local increase in cerebral blood flow in response to increased neuronal activity. Mechanisms of communication between neurons and blood vessels remain unclear. Astrocyte endfeet almost completely cover cerebral capillaries, suggesting that astrocytes play a role in NVC by releasing vasoactive substances near capillaries. An alternative hypothesis is that direct diffusion through the extracellular space of potassium ions (K+ ) released by neurons contributes to NVC. Here, the goal is to determine whether astrocyte endfeet present a barrier to K+ diffusion from neurons to capillaries. Two simplified 2D geometries of extracellular space, clefts between endfeet, and perivascular space are used: (i) a source 1 μm from a capillary; (ii) a neuron 15 μm from a capillary. K+ release is modelled as a step increase in [K+ ] at the outer boundary of the extracellular space. The time-dependent diffusion equation is solved numerically. In the first geometry, perivascular [K+ ] approaches its final value within 0.05 s. Decreasing endfeet cleft width or increasing perivascular space width slows the rise in [K+ ]. In the second geometry, the increase in perivascular [K+ ] occurs within 0.5 s and is insensitive to changes in cleft width or perivascular space width. Predicted levels of perivascular [K+ ] are sufficient to cause vasodilation, and the rise time is within the time for flow increase in NVC. These results suggest that direct diffusion of K+ through the extracellular space is a possible NVC signalling mechanism.
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Affiliation(s)
- Sara Djurich
- Department of Physiology, University of Arizona, Tucson, Arizona, USA
| | - Timothy W Secomb
- Department of Physiology, University of Arizona, Tucson, Arizona, USA
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15
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Ishii K, Izaki T, Asahara R, Komine H. Carotid sinus baroafferent signals contribute to cerebral blood flow regulation during acute hypotension in young males: A randomized crossover study. Physiol Rep 2024; 12:e15937. [PMID: 38325901 PMCID: PMC10849886 DOI: 10.14814/phy2.15937] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 01/10/2024] [Accepted: 01/21/2024] [Indexed: 02/09/2024] Open
Abstract
Cerebral autoregulation is an important factor in prevention of cerebral ischemic events. We tested a traditional but unproven hypothesis that carotid sinus baroafferent signals contribute to dynamic cerebral autoregulation. Middle cerebral artery mean blood velocity (MCA Vmean ) responses to thigh-cuff deflation-induced acute hypotension were compared between conditions using neck suction soon after cuff deflation, without or with a cushion wrapped around the upper neck, in nine healthy males (aged 25 ± 5 years). Neck suction was applied close to the hypotension. The MCA Vmean response was expected to differ between conditions because the cushion was presumed to prevent the carotid sinus distension by neck suction. The cushion hindered bradycardia and depressor responses during sole neck suction. Thigh-cuff deflation decreased mean arterial blood pressure (MAP) and MCA Vmean (Ps < 0.05) with an almost unchanged respiratory rate under both conditions. However, in the neck suction + cushion condition, subsequent MCA Vmean restoration was faster and greater (Ps ≤ 0.0131), despite similar changes in MAP in both conditions. Thus, carotid sinus baroafferent signals would accelerate dynamic cerebral autoregulation during rapid hypotension in healthy young males. Elucidating the mechanism underlying cerebral neural autoregulation could provide a new target for preventing cerebral ischemic events.
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Affiliation(s)
- Kei Ishii
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Tsubasa Izaki
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
- School of Economics & ManagementKochi University of TechnologyKochiJapan
| | - Ryota Asahara
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Hidehiko Komine
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and TechnologyTsukubaJapan
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16
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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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17
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Li F, Gallego J, Tirko NN, Greaser J, Bashe D, Patel R, Shaker E, Van Valkenburg GE, Alsubhi AS, Wellman S, Singh V, Padill CG, Gheres KW, Bagwell R, Mulvihill M, Kozai TDY. Low-intensity pulsed ultrasound stimulation (LIPUS) modulates microglial activation following intracortical microelectrode implantation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570162. [PMID: 38105969 PMCID: PMC10723293 DOI: 10.1101/2023.12.05.570162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Microglia are important players in surveillance and repair of the brain. Their activation mediates neuroinflammation caused by intracortical microelectrode implantation, which impedes the application of intracortical brain-computer interfaces (BCIs). While low-intensity pulsed ultrasound stimulation (LIPUS) can attenuate microglial activation, its potential to modulate the microglia-mediated neuroinflammation and enhance the bio-integration of microelectrodes remains insufficiently explored. We found that LIPUS increased microglia migration speed from 0.59±0.04 to 1.35±0.07 µm/hr on day 1 and enhanced microglia expansion area from 44.50±6.86 to 93.15±8.77 µm 2 /min on day 7, indicating improved tissue healing and surveillance. Furthermore, LIPUS reduced microglial activation by 17% on day 6, vessel-associated microglia ratio from 70.67±6.15 to 40.43±3.87% on day 7, and vessel diameter by 20% on day 28. Additionally, microglial coverage of the microelectrode was reduced by 50% in week 1, indicating better tissue-microelectrode integration. These data reveal that LIPUS helps resolve neuroinflammation around chronic intracortical microelectrodes.
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18
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Alarcon-Martinez L, Shiga Y, Villafranca-Baughman D, Cueva Vargas JL, Vidal Paredes IA, Quintero H, Fortune B, Danesh-Meyer H, Di Polo A. Neurovascular dysfunction in glaucoma. Prog Retin Eye Res 2023; 97:101217. [PMID: 37778617 DOI: 10.1016/j.preteyeres.2023.101217] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/23/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Retinal ganglion cells, the neurons that die in glaucoma, are endowed with a high metabolism requiring optimal provision of oxygen and nutrients to sustain their activity. The timely regulation of blood flow is, therefore, essential to supply firing neurons in active areas with the oxygen and glucose they need for energy. Many glaucoma patients suffer from vascular deficits including reduced blood flow, impaired autoregulation, neurovascular coupling dysfunction, and blood-retina/brain-barrier breakdown. These processes are tightly regulated by a community of cells known as the neurovascular unit comprising neurons, endothelial cells, pericytes, Müller cells, astrocytes, and microglia. In this review, the neurovascular unit takes center stage as we examine the ability of its members to regulate neurovascular interactions and how their function might be altered during glaucomatous stress. Pericytes receive special attention based on recent data demonstrating their key role in the regulation of neurovascular coupling in physiological and pathological conditions. Of particular interest is the discovery and characterization of tunneling nanotubes, thin actin-based conduits that connect distal pericytes, which play essential roles in the complex spatial and temporal distribution of blood within the retinal capillary network. We discuss cellular and molecular mechanisms of neurovascular interactions and their pathophysiological implications, while highlighting opportunities to develop strategies for vascular protection and regeneration to improve functional outcomes in glaucoma.
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Affiliation(s)
- Luis Alarcon-Martinez
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada; Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia
| | - Yukihiro Shiga
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Deborah Villafranca-Baughman
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Jorge L Cueva Vargas
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Isaac A Vidal Paredes
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Heberto Quintero
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada
| | - Brad Fortune
- Discoveries in Sight Research Laboratories, Devers Eye Institute and Legacy Research Institute, Legacy Healthy, Portland, OR, USA
| | - Helen Danesh-Meyer
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, New Zealand
| | - Adriana Di Polo
- Department of Neuroscience, Université de Montréal, PO Box 6128, Station centre-ville, Montreal, QC, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), 900 Saint Denis Street, Montreal, QC, Canada.
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19
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Siddiqui M, Pinti P, Brigadoi S, Lloyd-Fox S, Elwell CE, Johnson MH, Tachtsidis I, Jones EJH. Using multi-modal neuroimaging to characterise social brain specialisation in infants. eLife 2023; 12:e84122. [PMID: 37818944 PMCID: PMC10624424 DOI: 10.7554/elife.84122] [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: 10/11/2022] [Accepted: 10/10/2023] [Indexed: 10/13/2023] Open
Abstract
The specialised regional functionality of the mature human cortex partly emerges through experience-dependent specialisation during early development. Our existing understanding of functional specialisation in the infant brain is based on evidence from unitary imaging modalities and has thus focused on isolated estimates of spatial or temporal selectivity of neural or haemodynamic activation, giving an incomplete picture. We speculate that functional specialisation will be underpinned by better coordinated haemodynamic and metabolic changes in a broadly orchestrated physiological response. To enable researchers to track this process through development, we develop new tools that allow the simultaneous measurement of coordinated neural activity (EEG), metabolic rate, and oxygenated blood supply (broadband near-infrared spectroscopy) in the awake infant. In 4- to 7-month-old infants, we use these new tools to show that social processing is accompanied by spatially and temporally specific increases in coupled activation in the temporal-parietal junction, a core hub region of the adult social brain. During non-social processing, coupled activation decreased in the same region, indicating specificity to social processing. Coupling was strongest with high-frequency brain activity (beta and gamma), consistent with the greater energetic requirements and more localised action of high-frequency brain activity. The development of simultaneous multimodal neural measures will enable future researchers to open new vistas in understanding functional specialisation of the brain.
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Affiliation(s)
- Maheen Siddiqui
- Centre for Brain and Cognitive Development, Birkbeck, University of LondonLondonUnited Kingdom
| | - Paola Pinti
- Centre for Brain and Cognitive Development, Birkbeck, University of LondonLondonUnited Kingdom
| | - Sabrina Brigadoi
- Department of Development and Social Psychology, University of PadovaPadovaItaly
- Department of Information Engineering, University of PadovaPadovaItaly
| | - Sarah Lloyd-Fox
- Department of Psychology, University of CambridgeCambridgeUnited Kingdom
| | - Clare E Elwell
- Department of Medical Physics and Biomedical Engineering, University College LondonLondonUnited Kingdom
| | - Mark H Johnson
- Department of Psychology, University of CambridgeCambridgeUnited Kingdom
| | - Ilias Tachtsidis
- Department of Medical Physics and Biomedical Engineering, University College LondonLondonUnited Kingdom
| | - Emily JH Jones
- Centre for Brain and Cognitive Development, Birkbeck, University of LondonLondonUnited Kingdom
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20
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Ahn SJ, Anfray A, Anrather J, Iadecola C. Calcium transients in nNOS neurons underlie distinct phases of the neurovascular response to barrel cortex activation in awake mice. J Cereb Blood Flow Metab 2023; 43:1633-1647. [PMID: 37149758 PMCID: PMC10581240 DOI: 10.1177/0271678x231173175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 03/14/2023] [Accepted: 04/02/2023] [Indexed: 05/08/2023]
Abstract
Neuronal nitric oxide (NO) synthase (nNOS), a Ca2+ dependent enzyme, is expressed by distinct populations of neocortical neurons. Although neuronal NO is well known to contribute to the blood flow increase evoked by neural activity, the relationships between nNOS neurons activity and vascular responses in the awake state remain unclear. We imaged the barrel cortex in awake, head-fixed mice through a chronically implanted cranial window. The Ca2+ indicator GCaMP7f was expressed selectively in nNOS neurons using adenoviral gene transfer in nNOScre mice. Air-puffs directed at the contralateral whiskers or spontaneous motion induced Ca2+ transients in 30.2 ± 2.2% or 51.6 ± 3.3% of nNOS neurons, respectively, and evoked local arteriolar dilation. The greatest dilatation (14.8 ± 1.1%) occurred when whisking and motion occurred simultaneously. Ca2+ transients in individual nNOS neurons and local arteriolar dilation showed various degrees of correlation, which was strongest when the activity of whole nNOS neuron ensemble was examined. We also found that some nNOS neurons became active immediately prior to arteriolar dilation, while others were activated gradually after arteriolar dilatation. Discrete nNOS neuron subsets may contribute either to the initiation or to the maintenance of the vascular response, suggesting a previously unappreciated temporal specificity to the role of NO in neurovascular coupling.
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Affiliation(s)
- Sung Ji Ahn
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Antoine Anfray
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Josef Anrather
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Costantino Iadecola
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
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21
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Mitchell JW, Gillette MU. Development of circadian neurovascular function and its implications. Front Neurosci 2023; 17:1196606. [PMID: 37732312 PMCID: PMC10507717 DOI: 10.3389/fnins.2023.1196606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 08/14/2023] [Indexed: 09/22/2023] Open
Abstract
The neurovascular system forms the interface between the tissue of the central nervous system (CNS) and circulating blood. It plays a critical role in regulating movement of ions, small molecules, and cellular regulators into and out of brain tissue and in sustaining brain health. The neurovascular unit (NVU), the cells that form the structural and functional link between cells of the brain and the vasculature, maintains the blood-brain interface (BBI), controls cerebral blood flow, and surveils for injury. The neurovascular system is dynamic; it undergoes tight regulation of biochemical and cellular interactions to balance and support brain function. Development of an intrinsic circadian clock enables the NVU to anticipate rhythmic changes in brain activity and body physiology that occur over the day-night cycle. The development of circadian neurovascular function involves multiple cell types. We address the functional aspects of the circadian clock in the components of the NVU and their effects in regulating neurovascular physiology, including BBI permeability, cerebral blood flow, and inflammation. Disrupting the circadian clock impairs a number of physiological processes associated with the NVU, many of which are correlated with an increased risk of dysfunction and disease. Consequently, understanding the cell biology and physiology of the NVU is critical to diminishing consequences of impaired neurovascular function, including cerebral bleeding and neurodegeneration.
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Affiliation(s)
- Jennifer W. Mitchell
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Martha U. Gillette
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Carle-Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, IL, United States
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22
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Abstract
The vasculature consists of vessels of different sizes that are arranged in a hierarchical pattern. Two cell populations work in concert to establish this pattern during embryonic development and adopt it to changes in blood flow demand later in life: endothelial cells that line the inner surface of blood vessels, and adjacent vascular mural cells, including smooth muscle cells and pericytes. Despite recent progress in elucidating the signalling pathways controlling their crosstalk, much debate remains with regard to how mural cells influence endothelial cell biology and thereby contribute to the regulation of blood vessel formation and diameters. In this Review, I discuss mural cell functions and their interactions with endothelial cells, focusing on how these interactions ensure optimal blood flow patterns. Subsequently, I introduce the signalling pathways controlling mural cell development followed by an overview of mural cell ontogeny with an emphasis on the distinguishing features of mural cells located on different types of blood vessels. Ultimately, I explore therapeutic strategies involving mural cells to alleviate tissue ischemia and improve vascular efficiency in a variety of diseases.
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Affiliation(s)
- Arndt F. Siekmann
- Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, 1114 Biomedical Research Building, 421 Curie Boulevard, Philadelphia, PA 19104, USA
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23
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Bailes SM, Gomez DEP, Setzer B, Lewis LD. Resting-state fMRI signals contain spectral signatures of local hemodynamic response timing. eLife 2023; 12:e86453. [PMID: 37565644 PMCID: PMC10506795 DOI: 10.7554/elife.86453] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Accepted: 08/10/2023] [Indexed: 08/12/2023] Open
Abstract
Functional magnetic resonance imaging (fMRI) has proven to be a powerful tool for noninvasively measuring human brain activity; yet, thus far, fMRI has been relatively limited in its temporal resolution. A key challenge is understanding the relationship between neural activity and the blood-oxygenation-level-dependent (BOLD) signal obtained from fMRI, generally modeled by the hemodynamic response function (HRF). The timing of the HRF varies across the brain and individuals, confounding our ability to make inferences about the timing of the underlying neural processes. Here, we show that resting-state fMRI signals contain information about HRF temporal dynamics that can be leveraged to understand and characterize variations in HRF timing across both cortical and subcortical regions. We found that the frequency spectrum of resting-state fMRI signals significantly differs between voxels with fast versus slow HRFs in human visual cortex. These spectral differences extended to subcortex as well, revealing significantly faster hemodynamic timing in the lateral geniculate nucleus of the thalamus. Ultimately, our results demonstrate that the temporal properties of the HRF impact the spectral content of resting-state fMRI signals and enable voxel-wise characterization of relative hemodynamic response timing. Furthermore, our results show that caution should be used in studies of resting-state fMRI spectral properties, because differences in fMRI frequency content can arise from purely vascular origins. This finding provides new insight into the temporal properties of fMRI signals across voxels, which is crucial for accurate fMRI analyses, and enhances the ability of fast fMRI to identify and track fast neural dynamics.
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Affiliation(s)
- Sydney M Bailes
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
| | - Daniel EP Gomez
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General HospitalCharlestownUnited States
- Department of Radiology, Harvard Medical SchoolBostonUnited States
| | - Beverly Setzer
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
- Graduate Program for Neuroscience, Boston UniversityBostonUnited States
| | - Laura D Lewis
- Department of Biomedical Engineering, Boston UniversityBostonUnited States
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General HospitalCharlestownUnited States
- Institute for Medical Engineering and Science, Massachusetts Institute of TechnologyCambridgeUnited States
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of TechnologyCambridgeUnited States
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24
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Smith CA, Carpenter KLH, Hutchinson PJ, Smielewski P, Helmy A. Candidate neuroinflammatory markers of cerebral autoregulation dysfunction in human acute brain injury. J Cereb Blood Flow Metab 2023; 43:1237-1253. [PMID: 37132274 PMCID: PMC10369156 DOI: 10.1177/0271678x231171991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 02/27/2023] [Accepted: 03/31/2023] [Indexed: 05/04/2023]
Abstract
The loss of cerebral autoregulation (CA) is a common and detrimental secondary injury mechanism following acute brain injury and has been associated with worse morbidity and mortality. However patient outcomes have not as yet been conclusively proven to have improved as a result of CA-directed therapy. While CA monitoring has been used to modify CPP targets, this approach cannot work if the impairment of CA is not simply related to CPP but involves other underlying mechanisms and triggers, which at present are largely unknown. Neuroinflammation, particularly inflammation affecting the cerebral vasculature, is an important cascade that occurs following acute injury. We hypothesise that disturbances to the cerebral vasculature can affect the regulation of CBF, and hence the vascular inflammatory pathways could be a putative mechanism that causes CA dysfunction. This review provides a brief overview of CA, and its impairment following brain injury. We discuss candidate vascular and endothelial markers and what is known about their link to disturbance of the CBF and autoregulation. We focus on human traumatic brain injury (TBI) and subarachnoid haemorrhage (SAH), with supporting evidence from animal work and applicability to wider neurologic diseases.
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Affiliation(s)
- Claudia A Smith
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Keri LH Carpenter
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Peter J Hutchinson
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Peter Smielewski
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Adel Helmy
- Division of Neurosurgery, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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25
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Inoue Y, Shue F, Bu G, Kanekiyo T. Pathophysiology and probable etiology of cerebral small vessel disease in vascular dementia and Alzheimer's disease. Mol Neurodegener 2023; 18:46. [PMID: 37434208 PMCID: PMC10334598 DOI: 10.1186/s13024-023-00640-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 06/28/2023] [Indexed: 07/13/2023] Open
Abstract
Vascular cognitive impairment and dementia (VCID) is commonly caused by vascular injuries in cerebral large and small vessels and is a key driver of age-related cognitive decline. Severe VCID includes post-stroke dementia, subcortical ischemic vascular dementia, multi-infarct dementia, and mixed dementia. While VCID is acknowledged as the second most common form of dementia after Alzheimer's disease (AD) accounting for 20% of dementia cases, VCID and AD frequently coexist. In VCID, cerebral small vessel disease (cSVD) often affects arterioles, capillaries, and venules, where arteriolosclerosis and cerebral amyloid angiopathy (CAA) are major pathologies. White matter hyperintensities, recent small subcortical infarcts, lacunes of presumed vascular origin, enlarged perivascular space, microbleeds, and brain atrophy are neuroimaging hallmarks of cSVD. The current primary approach to cSVD treatment is to control vascular risk factors such as hypertension, dyslipidemia, diabetes, and smoking. However, causal therapeutic strategies have not been established partly due to the heterogeneous pathogenesis of cSVD. In this review, we summarize the pathophysiology of cSVD and discuss the probable etiological pathways by focusing on hypoperfusion/hypoxia, blood-brain barriers (BBB) dysregulation, brain fluid drainage disturbances, and vascular inflammation to define potential diagnostic and therapeutic targets for cSVD.
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Affiliation(s)
- Yasuteru Inoue
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Francis Shue
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
| | - Guojun Bu
- SciNeuro Pharmaceuticals, Rockville, MD 20850 USA
| | - Takahisa Kanekiyo
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224 USA
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26
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Qian K, Jiang X, Liu ZQ, Zhang J, Fu P, Su Y, Brazhe NA, Liu D, Zhu LQ. Revisiting the critical roles of reactive astrocytes in neurodegeneration. Mol Psychiatry 2023; 28:2697-2706. [PMID: 37037874 DOI: 10.1038/s41380-023-02061-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 03/27/2023] [Accepted: 03/28/2023] [Indexed: 04/12/2023]
Abstract
Astrocytes, an integral component of the central nervous system (CNS), contribute to the maintenance of physiological homeostasis through their roles in synaptic function, K+ buffering, blood-brain barrier (BBB) maintenance, and neuronal metabolism. Reactive astrocytes refer to astrocytes undergoing morphological, molecular and functional remodelling in response to pathological stimuli. The activation and differentiation of astrocytes are implicated in the pathogenesis of multiple neurodegenerative diseases. However, there are still controversies regarding their subset identification, function and nomenclature in neurodegeneration. In this review, we revisit the multidimensional roles of reactive astrocytes in Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), multiple sclerosis (MS) and amyotrophic lateral sclerosis (ALS). Furthermore, we propose a precise linkage between astrocyte subsets and their functions based on single-cell sequencing analyses.
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Affiliation(s)
- Kang Qian
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Neurosurgery, Union Hospital, Huazhong University of Science and Technology, Jiefang Avenue No. 1277, 430022, Wuhan, China
| | - Xiaobing Jiang
- Department of Neurosurgery, Union Hospital, Huazhong University of Science and Technology, Jiefang Avenue No. 1277, 430022, Wuhan, China
| | - Zhi-Qiang Liu
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Juan Zhang
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Peng Fu
- Department of Neurosurgery, Union Hospital, Huazhong University of Science and Technology, Jiefang Avenue No. 1277, 430022, Wuhan, China
| | - Ying Su
- Department of Neurology, Union Hospital, Huazhong University of Science and Technology, Jiefang Avenue No. 1277, 430022, Wuhan, China
| | - Nadezda A Brazhe
- Biophysics Department, Biological Faculty, Moscow State University, Moscow, Russia
| | - Dan Liu
- Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Ling-Qiang Zhu
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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27
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Pommy J, Smart CM, Bryant AM, Wang Y. Three potential neurovascular pathways driving the benefits of mindfulness meditation for older adults. Front Aging Neurosci 2023; 15:1207012. [PMID: 37455940 PMCID: PMC10340530 DOI: 10.3389/fnagi.2023.1207012] [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: 04/16/2023] [Accepted: 06/06/2023] [Indexed: 07/18/2023] Open
Abstract
Mindfulness meditation has been shown to be beneficial for a range of different health conditions, impacts brain function and structure relatively quickly, and has shown promise with aging samples. Functional magnetic resonance imaging metrics provide insight into neurovascular health which plays a key role in both normal and pathological aging processes. Experimental mindfulness meditation studies that included functional magnetic resonance metrics as an outcome measure may point to potential neurovascular mechanisms of action relevant for aging adults that have not yet been previously examined. We first review the resting-state magnetic resonance studies conducted in exclusively older adult age samples. Findings from older adult-only samples are then used to frame the findings of task magnetic resonance imaging studies conducted in both clinical and healthy adult samples. Based on the resting-state studies in older adults and the task magnetic resonance studies in adult samples, we propose three potential mechanisms by which mindfulness meditation may offer a neurovascular therapeutic benefit for older adults: (1) a direct neurovascular mechanism via increased resting-state cerebral blood flow; (2) an indirect anti-neuroinflammatory mechanism via increased functional connectivity within the default mode network, and (3) a top-down control mechanism that likely reflects both a direct and an indirect neurovascular pathway.
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Affiliation(s)
- Jessica Pommy
- Department of Neurology, Division of Neuropsychology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Colette M. Smart
- Department of Psychology, University of Victoria, Victoria, BC, Canada
| | - Andrew M. Bryant
- Department of Neurology, The Ohio State University, Columbus, OH, United States
| | - Yang Wang
- Department of Neurology, Division of Neuropsychology, Medical College of Wisconsin, Milwaukee, WI, United States
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States
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28
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Iadecola C, Smith EE, Anrather J, Gu C, Mishra A, Misra S, Perez-Pinzon MA, Shih AY, Sorond FA, van Veluw SJ, Wellington CL. The Neurovasculome: Key Roles in Brain Health and Cognitive Impairment: A Scientific Statement From the American Heart Association/American Stroke Association. Stroke 2023; 54:e251-e271. [PMID: 37009740 PMCID: PMC10228567 DOI: 10.1161/str.0000000000000431] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
Abstract
BACKGROUND Preservation of brain health has emerged as a leading public health priority for the aging world population. Advances in neurovascular biology have revealed an intricate relationship among brain cells, meninges, and the hematic and lymphatic vasculature (the neurovasculome) that is highly relevant to the maintenance of cognitive function. In this scientific statement, a multidisciplinary team of experts examines these advances, assesses their relevance to brain health and disease, identifies knowledge gaps, and provides future directions. METHODS Authors with relevant expertise were selected in accordance with the American Heart Association conflict-of-interest management policy. They were assigned topics pertaining to their areas of expertise, reviewed the literature, and summarized the available data. RESULTS The neurovasculome, composed of extracranial, intracranial, and meningeal vessels, as well as lymphatics and associated cells, subserves critical homeostatic functions vital for brain health. These include delivering O2 and nutrients through blood flow and regulating immune trafficking, as well as clearing pathogenic proteins through perivascular spaces and dural lymphatics. Single-cell omics technologies have unveiled an unprecedented molecular heterogeneity in the cellular components of the neurovasculome and have identified novel reciprocal interactions with brain cells. The evidence suggests a previously unappreciated diversity of the pathogenic mechanisms by which disruption of the neurovasculome contributes to cognitive dysfunction in neurovascular and neurodegenerative diseases, providing new opportunities for the prevention, recognition, and treatment of these conditions. CONCLUSIONS These advances shed new light on the symbiotic relationship between the brain and its vessels and promise to provide new diagnostic and therapeutic approaches for brain disorders associated with cognitive dysfunction.
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29
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Williams RJ, Specht JL, Mazerolle EL, Lebel RM, MacDonald ME, Pike GB. Correspondence between BOLD fMRI task response and cerebrovascular reactivity across the cerebral cortex. Front Physiol 2023; 14:1167148. [PMID: 37228813 PMCID: PMC10203231 DOI: 10.3389/fphys.2023.1167148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/24/2023] [Indexed: 05/27/2023] Open
Abstract
BOLD sensitivity to baseline perfusion and blood volume is a well-acknowledged fMRI confound. Vascular correction techniques based on cerebrovascular reactivity (CVR) might reduce variance due to baseline cerebral blood volume, however this is predicated on an invariant linear relationship between CVR and BOLD signal magnitude. Cognitive paradigms have relatively low signal, high variance and involve spatially heterogenous cortical regions; it is therefore unclear whether the BOLD response magnitude to complex paradigms can be predicted by CVR. The feasibility of predicting BOLD signal magnitude from CVR was explored in the present work across two experiments using different CVR approaches. The first utilized a large database containing breath-hold BOLD responses and 3 different cognitive tasks. The second experiment, in an independent sample, calculated CVR using the delivery of a fixed concentration of carbon dioxide and a different cognitive task. An atlas-based regression approach was implemented for both experiments to evaluate the shared variance between task-invoked BOLD responses and CVR across the cerebral cortex. Both experiments found significant relationships between CVR and task-based BOLD magnitude, with activation in the right cuneus (R 2 = 0.64) and paracentral gyrus (R 2 = 0.71), and the left pars opercularis (R 2 = 0.67), superior frontal gyrus (R 2 = 0.62) and inferior parietal cortex (R 2 = 0.63) strongly predicted by CVR. The parietal regions bilaterally were highly consistent, with linear regressions significant in these regions for all four tasks. Group analyses showed that CVR correction increased BOLD sensitivity. Overall, this work suggests that BOLD signal response magnitudes to cognitive tasks are predicted by CVR across different regions of the cerebral cortex, providing support for the use of correction based on baseline vascular physiology.
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Affiliation(s)
- Rebecca J. Williams
- Faculty of Health, School of Human Services, Charles Darwin University, Darwin, NT, Australia
| | - Jacinta L. Specht
- Department of Clinical Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Erin L. Mazerolle
- Departments of Psychology and Computer Science, St. Francis Xavier University, Antigonish, NS, Canada
| | - R. Marc Lebel
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- GE HealthCare, Calgary, AB, Canada
| | - M. Ethan MacDonald
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
- Department of Electrical and Software Engineering, Schulich School of Engineering, University of Calgary, Calgary, AB, Canada
| | - G. Bruce Pike
- Department of Clinical Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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30
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Eisenmenger LB, Peret A, Famakin BM, Spahic A, Roberts GS, Bockholt JH, Johnson KM, Paulsen JS. Vascular contributions to Alzheimer's disease. Transl Res 2023; 254:41-53. [PMID: 36529160 PMCID: PMC10481451 DOI: 10.1016/j.trsl.2022.12.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/05/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia and is characterized by progressive neurodegeneration and cognitive decline. Understanding the pathophysiology underlying AD is paramount for the management of individuals at risk of and suffering from AD. The vascular hypothesis stipulates a relationship between cardiovascular disease and AD-related changes although the nature of this relationship remains unknown. In this review, we discuss several potential pathological pathways of vascular involvement in AD that have been described including dysregulation of neurovascular coupling, disruption of the blood brain barrier, and reduced clearance of metabolite waste such as beta-amyloid, a toxic peptide considered the hallmark of AD. We will also discuss the two-hit hypothesis which proposes a 2-step positive feedback loop in which microvascular insults precede the accumulation of Aß and are thought to be at the origin of the disease development. At neuroimaging, signs of vascular dysfunction such as chronic cerebral hypoperfusion have been demonstrated, appearing early in AD, even before cognitive decline and alteration of traditional biomarkers. Cerebral small vessel disease such as cerebral amyloid angiopathy, characterized by the aggregation of Aß in the vessel wall, is highly prevalent in vascular dementia and AD patients. Current data is unclear whether cardiovascular disease causes, precipitates, amplifies, precedes, or simply coincides with AD. Targeted imaging tools to quantitatively evaluate the intracranial vasculature and longitudinal studies in individuals at risk for or in the early stages of the AD continuum could be critical in disentangling this complex relationship between vascular disease and AD.
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Affiliation(s)
- Laura B Eisenmenger
- Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Anthony Peret
- Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Bolanle M Famakin
- Department of Neurology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Alma Spahic
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Grant S Roberts
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Jeremy H Bockholt
- Tri-Institutional Center for Translational Research in Neuroimaging and Data Science (TReNDS), Georgia State University, Georgia Institute of Technology, and Emory University, Atlanta, Georgia
| | - Kevin M Johnson
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin
| | - Jane S Paulsen
- Department of Neurology, University of Wisconsin-Madison, Madison, Wisconsin.
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David T, Morillo R, Howarth C, Berwick J, Lee L. The Reversal Characteristics of GABAergic Neurons: A Neurovascular Model. J Biomech Eng 2023; 145:031007. [PMID: 36445228 PMCID: PMC7615696 DOI: 10.1115/1.4056336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 11/23/2022] [Indexed: 12/03/2022]
Abstract
Neurovascular coupling (NVC) is the ability to locally adjust vascular resistance as a function of neuronal activity. Recent experiments have illustrated that NVC is partially independent of metabolic signals. In addition, nitric oxide (NO) has been shown in some instances to provide an important mechanism in altering vascular resistance. An extension to the original model of NVC [1] has been developed to include the activation of both somatosensory neurons and GABAergic interneurons and to investigate the role of NO and the delicate balance of GABA and neuronal peptide enzymes (NPY) pathways. The numerical model is compared to murine experimental data that provides time-dependent profiles of oxy, de-oxy, and total-hemoglobin. The results indicate a delicate balance that exists between GABA and NPY when nNOS interneurons are activated mediated by NO. Whereas somatosensory neurons (producing potassium into the extracellular space) do not seem to be effected by the inhibition of NO. Further work will need to be done to investigate the role of NO when stimulation periods are increased substantially from the short pulses of 2 s as used in the above experiments.
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Affiliation(s)
- Tim David
- Department of Mechanical Engineering University of Canterbury Christchurch, New Zealand
| | - Robin Morillo
- Department of Mathematics North Carolina State University
| | - Clare Howarth
- Department of Psychology University of Sheffield, U.K
| | - Jason Berwick
- Department of Psychology University of Sheffield, U.K
| | - Llywelyn Lee
- Department of Psychology University of Sheffield, U.K
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Barros LF, Ruminot I, Sotelo-Hitschfeld T, Lerchundi R, Fernández-Moncada I. Metabolic Recruitment in Brain Tissue. Annu Rev Physiol 2023; 85:115-135. [PMID: 36270291 DOI: 10.1146/annurev-physiol-021422-091035] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Information processing imposes urgent metabolic demands on neurons, which have negligible energy stores and restricted access to fuel. Here, we discuss metabolic recruitment, the tissue-level phenomenon whereby active neurons harvest resources from their surroundings. The primary event is the neuronal release of K+ that mirrors workload. Astrocytes sense K+ in exquisite fashion thanks to their unique coexpression of NBCe1 and α2β2 Na+/K+ ATPase, and within seconds switch to Crabtree metabolism, involving GLUT1, aerobic glycolysis, transient suppression of mitochondrial respiration, and lactate export. The lactate surge serves as a secondary recruiter by inhibiting glucose consumption in distant cells. Additional recruiters are glutamate, nitric oxide, and ammonium, which signal over different spatiotemporal domains. The net outcome of these events is that more glucose, lactate, and oxygen are made available. Metabolic recruitment works alongside neurovascular coupling and various averaging strategies to support the inordinate dynamic range of individual neurons.
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Affiliation(s)
- L F Barros
- Centro de Estudios Científicos (CECs), Valdivia, Chile; .,Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile;
| | - I Ruminot
- Centro de Estudios Científicos (CECs), Valdivia, Chile; .,Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile;
| | - T Sotelo-Hitschfeld
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - R Lerchundi
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), MIRCen, Fontenay-aux-Roses, France
| | - I Fernández-Moncada
- NeuroCentre Magendie, INSERM U1215, University of Bordeaux, Bordeaux, France
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Bailes SM, Gomez DEP, Setzer B, Lewis LD. Resting-state fMRI signals contain spectral signatures of local hemodynamic response timing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.25.525528. [PMID: 36747821 PMCID: PMC9900794 DOI: 10.1101/2023.01.25.525528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Functional magnetic resonance imaging (fMRI) has proven to be a powerful tool for noninvasively measuring human brain activity; yet, thus far, fMRI has been relatively limited in its temporal resolution. A key challenge is understanding the relationship between neural activity and the blood-oxygenation-level-dependent (BOLD) signal obtained from fMRI, generally modeled by the hemodynamic response function (HRF). The timing of the HRF varies across the brain and individuals, confounding our ability to make inferences about the timing of the underlying neural processes. Here we show that resting-state fMRI signals contain information about HRF temporal dynamics that can be leveraged to understand and characterize variations in HRF timing across both cortical and subcortical regions. We found that the frequency spectrum of resting-state fMRI signals significantly differs between voxels with fast versus slow HRFs in human visual cortex. These spectral differences extended to subcortex as well, revealing significantly faster hemodynamic timing in the lateral geniculate nucleus of the thalamus. Ultimately, our results demonstrate that the temporal properties of the HRF impact the spectral content of resting-state fMRI signals and enable voxel-wise characterization of relative hemodynamic response timing. Furthermore, our results show that caution should be used in studies of resting-state fMRI spectral properties, as differences can arise from purely vascular origins. This finding provides new insight into the temporal properties of fMRI signals across voxels, which is crucial for accurate fMRI analyses, and enhances the ability of fast fMRI to identify and track fast neural dynamics.
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Affiliation(s)
| | - Daniel E. P. Gomez
- Department of Biomedical Engineering, Boston, MA, 02215, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, 02129, USA
- Department of Radiology, Harvard Medical School, Boston, MA 02115, USA
| | - Beverly Setzer
- Department of Biomedical Engineering, Boston, MA, 02215, USA
- Graduate Program for Neuroscience, Boston University, Boston, MA, 02215, USA
| | - Laura D. Lewis
- Department of Biomedical Engineering, Boston, MA, 02215, USA
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, 02129, USA
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Hadjihambi A, Konstantinou C, Klohs J, Monsorno K, Le Guennec A, Donnelly C, Cox IJ, Kusumbe A, Hosford PS, Soffientini U, Lecca S, Mameli M, Jalan R, Paolicelli RC, Pellerin L. Partial MCT1 invalidation protects against diet-induced non-alcoholic fatty liver disease and the associated brain dysfunction. J Hepatol 2023; 78:180-190. [PMID: 35995127 DOI: 10.1016/j.jhep.2022.08.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 07/30/2022] [Accepted: 08/05/2022] [Indexed: 02/01/2023]
Abstract
BACKGROUND & AIMS Non-alcoholic fatty liver disease (NAFLD) has been associated with mild cerebral dysfunction and cognitive decline, although the exact pathophysiological mechanism remains ambiguous. Using a diet-induced model of NAFLD and monocarboxylate transporter-1 (Mct1+/-) haploinsufficient mice, which resist high-fat diet-induced hepatic steatosis, we investigated the hypothesis that NAFLD leads to an encephalopathy by altering cognition, behaviour, and cerebral physiology. We also proposed that global MCT1 downregulation offers cerebral protection. METHODS Behavioural tests were performed in mice following 16 weeks of control diet (normal chow) or high-fat diet with high fructose/glucose in water. Tissue oxygenation, cerebrovascular reactivity, and cerebral blood volume were monitored under anaesthesia by multispectral optoacoustic tomography and optical fluorescence. Cortical mitochondrial oxygen consumption and respiratory capacities were measured using ex vivo high-resolution respirometry. Microglial and astrocytic changes were evaluated by immunofluorescence and 3D reconstructions. Body composition was assessed using EchoMRI, and liver steatosis was confirmed by histology. RESULTS NAFLD concomitant with obesity is associated with anxiety- and depression-related behaviour. Low-grade brain tissue hypoxia was observed, likely attributed to the low-grade brain inflammation and decreased cerebral blood volume. It is also accompanied by microglial and astrocytic morphological and metabolic alterations (higher oxygen consumption), suggesting the early stages of an obesogenic diet-induced encephalopathy. Mct1 haploinsufficient mice, despite fat accumulation in adipose tissue, were protected from NAFLD and associated cerebral alterations. CONCLUSIONS This study provides evidence of compromised brain health in obesity and NAFLD, emphasising the importance of the liver-brain axis. The protective effect of Mct1 haploinsufficiency points to this protein as a novel therapeutic target for preventing and/or treating NAFLD and the associated brain dysfunction. IMPACT AND IMPLICATIONS This study is focused on unravelling the pathophysiological mechanism by which cerebral dysfunction and cognitive decline occurs during NAFLD and exploring the potential of monocarboxylate transporter-1 (MCT1) as a novel preventive or therapeutic target. Our findings point to NAFLD as a serious health risk and its adverse impact on the brain as a potential global health system and economic burden. These results highlight the utility of Mct1 transgenic mice as a model for NAFLD and associated brain dysfunction and call for systematic screening by physicians for early signs of psychological symptoms, and an awareness by individuals at risk of these potential neurological effects. This study is expected to bring attention to the need for early diagnosis and treatment of NAFLD, while having a direct impact on policies worldwide regarding the health risk associated with NAFLD, and its prevention and treatment.
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Affiliation(s)
- Anna Hadjihambi
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland; The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK; Faculty of Life Sciences and Medicine, King's College London, London, UK.
| | - Christos Konstantinou
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK; Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Jan Klohs
- Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland; Neuroscience Centre Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Katia Monsorno
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | | | - Chris Donnelly
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland; Institute of Sports Science, University of Lausanne, Lausanne, Switzerland
| | - I Jane Cox
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK; Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Anjali Kusumbe
- Tissue and Tumor Microenvironments Group, MRC Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Patrick S Hosford
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Ugo Soffientini
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK; Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Salvatore Lecca
- The Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Manuel Mameli
- The Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland; Inserm, UMR-S 839, Paris, France
| | - Rajiv Jalan
- Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, University College London, London, UK
| | | | - Luc Pellerin
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland; Inserm U1313, Université de Poitiers et CHU de Poitiers, France.
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Grubb S. Ultrastructure of precapillary sphincters and the neurovascular unit. VASCULAR BIOLOGY (BRISTOL, ENGLAND) 2023; 5:e230011. [PMID: 37855433 PMCID: PMC10762554 DOI: 10.1530/vb-23-0011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 10/09/2023] [Indexed: 10/20/2023]
Abstract
Neurons communicate with vasculature to regulate blood flow in the brain, a process maintained by the neurovascular unit (NVU). This interaction, termed neurovascular coupling, is believed to involve astrocytes or molecules capable of traversing the astrocytic endfeet. The precise mechanism, however, remains elusive. Using large 3D electron microscopy datasets, we can now study the entire NVU in context of vascular hierarchy. This study presents evidence supporting the role of precapillary sphincters as a nexus for neurovascular coupling and endothelial transcytosis. It also highlights the role of fibroblast-synthesized collagen in fortifying first-order capillaries. Furthermore, I demonstrate how astrocytic endfeet establish a barrier for fluid flow and reveal that the cortex's microvasculature is semicircled by an unexpected arrangement of parenchymal neuronal processes around penetrating arterioles and arterial-end capillaries in both mouse and human brains. These discoveries offer insights into the NVU's structure and its operational mechanisms, potentially aiding researchers in devising new strategies for preserving cognitive function and promoting healthy aging.
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Affiliation(s)
- Søren Grubb
- Department of Neuroscience and Center for Translational Neuromedicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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36
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Zhang Q, Haselden WD, Charpak S, Drew PJ. Could respiration-driven blood oxygen changes modulate neural activity? Pflugers Arch 2023; 475:37-48. [PMID: 35761104 PMCID: PMC9794637 DOI: 10.1007/s00424-022-02721-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 05/26/2022] [Accepted: 06/16/2022] [Indexed: 01/31/2023]
Abstract
Oxygen is critical for neural metabolism, but under most physiological conditions, oxygen levels in the brain are far more than are required. Oxygen levels can be dynamically increased by increases in respiration rate that are tied to the arousal state of the brain and cognition, and not necessarily linked to exertion by the body. Why these changes in respiration occur when oxygen is already adequate has been a long-standing puzzle. In humans, performance on cognitive tasks can be affected by very high or very low oxygen levels, but whether the physiological changes in blood oxygenation produced by respiration have an appreciable effect is an open question. Oxygen has direct effects on potassium channels, increases the degradation rate of nitric oxide, and is rate limiting for the synthesis of some neuromodulators. We discuss whether oxygenation changes due to respiration contribute to neural dynamics associated with attention and arousal.
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Affiliation(s)
- Qingguang Zhang
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - William D Haselden
- Medical Scientist Training Program, College of Medicine, The Pennsylvania State University, Hershey, PA, 17033, USA
| | - Serge Charpak
- Institut de La Vision, INSERM, CNRS, Sorbonne Université, Paris, France
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Patrick J Drew
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, 16802, USA.
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Institoris A, Vandal M, Peringod G, Catalano C, Tran CH, Yu X, Visser F, Breiteneder C, Molina L, Khakh BS, Nguyen MD, Thompson RJ, Gordon GR. Astrocytes amplify neurovascular coupling to sustained activation of neocortex in awake mice. Nat Commun 2022; 13:7872. [PMID: 36550102 PMCID: PMC9780254 DOI: 10.1038/s41467-022-35383-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 11/30/2022] [Indexed: 12/24/2022] Open
Abstract
Functional hyperemia occurs when enhanced neuronal activity signals to increase local cerebral blood flow (CBF) to satisfy regional energy demand. Ca2+ elevation in astrocytes can drive arteriole dilation to increase CBF, yet affirmative evidence for the necessity of astrocytes in functional hyperemia in vivo is lacking. In awake mice, we discovered that functional hyperemia is bimodal with a distinct early and late component whereby arteriole dilation progresses as sensory stimulation is sustained. Clamping astrocyte Ca2+ signaling in vivo by expressing a plasma membrane Ca2+ ATPase (CalEx) reduces sustained but not brief sensory-evoked arteriole dilation. Elevating astrocyte free Ca2+ using chemogenetics selectively augments sustained hyperemia. Antagonizing NMDA-receptors or epoxyeicosatrienoic acid production reduces only the late component of functional hyperemia, leaving brief increases in CBF to sensory stimulation intact. We propose that a fundamental role of astrocyte Ca2+ is to amplify functional hyperemia when neuronal activation is prolonged.
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Affiliation(s)
- Adam Institoris
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Milène Vandal
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Govind Peringod
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Christy Catalano
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Cam Ha Tran
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
- Department of Physiology and Cell Biology, Reno School of Medicine, University of Nevada, Reno, NV, 89557-352, USA
| | - Xinzhu Yu
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095-1751, USA
- Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095-1751, USA
- Department of Molecular and Integrative Physiology, Beckman Institute, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Frank Visser
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Cheryl Breiteneder
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Leonardo Molina
- Hotchkiss Brain Institute, Department of Clinical Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095-1751, USA
- Department of Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095-1751, USA
| | - Minh Dang Nguyen
- Hotchkiss Brain Institute, Department of Clinical Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Roger J Thompson
- Hotchkiss Brain Institute, Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada
| | - Grant R Gordon
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
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O’Gallagher K, Rosentreter RE, Elaine Soriano J, Roomi A, Saleem S, Lam T, Roy R, Gordon GR, Raj SR, Chowienczyk PJ, Shah AM, Phillips AA. The Effect of a Neuronal Nitric Oxide Synthase Inhibitor on Neurovascular Regulation in Humans. Circ Res 2022; 131:952-961. [PMID: 36349758 PMCID: PMC9770134 DOI: 10.1161/circresaha.122.321631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Neurovascular coupling (NVC) is a key process in cerebral blood flow regulation. NVC ensures adequate brain perfusion to changes in local metabolic demands. Neuronal nitric oxide synthase (nNOS) is suspected to be involved in NVC; however, this has not been tested in humans. Our objective was to investigate the effects of nNOS inhibition on NVC in humans. METHODS We performed a 3-visit partially randomized, double-blinded, placebo-controlled, crossover study in 12 healthy subjects. On each visit, subjects received an intravenous infusion of either S-methyl-L-thiocitrulline (a selective nNOS-inhibitor), 0.9% saline (placebo control), or phenylephrine (pressor control). The NVC assessment involved eliciting posterior circulation hyperemia through visual stimulation while measuring posterior and middle cerebral arteries blood velocity. RESULTS nNOS inhibition blunted the rapidity of the NVC response versus pressor control, evidenced by a reduced initial rise in mean posterior cerebral artery velocity (-3.3% [-6.5, -0.01], P=0.049), and a reduced rate of increase (ie, acceleration) in posterior cerebral artery velocity (slope reduced -4.3% [-8.5, -0.1], P=0.045). The overall magnitude of posterior cerebral artery response relative to placebo control or pressor control was not affected. Changes in BP parameters were well-matched between the S-methyl-L-thiocitrulline and pressor control arms. CONCLUSIONS Neuronal NOS plays a role in dynamic cerebral blood flow control in healthy adults, particularly the rapidity of the NVC response to visual stimulation. This work opens the way to further investigation of the role of nNOS in conditions of impaired NVC, potentially revealing a therapeutic target.
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Affiliation(s)
- Kevin O’Gallagher
- School of Cardiovascular and Metabolic Medicine & Sciences, King’s College London British Heart Foundation Centre of Research Excellence, London, UK (K.O., A.R., R.R., P.J.C., A.M.S.).,NIHR Biomedical Research Centre, Clinical Research Facility, Guy’s and St Thomas NHS Foundation Trust, London, UK (K.O., A.R., P.J.C., A.M.S.)
| | - Ryan E. Rosentreter
- Departments of Physiology and Pharmacology, Clinical Neurosciences, Cardiac Sciences, Hotchkiss Brain Institute, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Alberta, Canada (R.E.R, J.E.S., T.L., G.R.G., S.R.R., A.A.P.)
| | - Jan Elaine Soriano
- Departments of Physiology and Pharmacology, Clinical Neurosciences, Cardiac Sciences, Hotchkiss Brain Institute, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Alberta, Canada (R.E.R, J.E.S., T.L., G.R.G., S.R.R., A.A.P.)
| | - Ali Roomi
- School of Cardiovascular and Metabolic Medicine & Sciences, King’s College London British Heart Foundation Centre of Research Excellence, London, UK (K.O., A.R., R.R., P.J.C., A.M.S.).,NIHR Biomedical Research Centre, Clinical Research Facility, Guy’s and St Thomas NHS Foundation Trust, London, UK (K.O., A.R., P.J.C., A.M.S.)
| | - Saqib Saleem
- Department of Electrical and Computer Engineering, COMSATS University, Sahiwal, Pakistan (S.S.)
| | - Tyler Lam
- Departments of Physiology and Pharmacology, Clinical Neurosciences, Cardiac Sciences, Hotchkiss Brain Institute, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Alberta, Canada (R.E.R, J.E.S., T.L., G.R.G., S.R.R., A.A.P.)
| | - Roman Roy
- School of Cardiovascular and Metabolic Medicine & Sciences, King’s College London British Heart Foundation Centre of Research Excellence, London, UK (K.O., A.R., R.R., P.J.C., A.M.S.)
| | - Grant R. Gordon
- Departments of Physiology and Pharmacology, Clinical Neurosciences, Cardiac Sciences, Hotchkiss Brain Institute, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Alberta, Canada (R.E.R, J.E.S., T.L., G.R.G., S.R.R., A.A.P.)
| | - Satish R. Raj
- Departments of Physiology and Pharmacology, Clinical Neurosciences, Cardiac Sciences, Hotchkiss Brain Institute, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Alberta, Canada (R.E.R, J.E.S., T.L., G.R.G., S.R.R., A.A.P.)
| | - Philip J. Chowienczyk
- School of Cardiovascular and Metabolic Medicine & Sciences, King’s College London British Heart Foundation Centre of Research Excellence, London, UK (K.O., A.R., R.R., P.J.C., A.M.S.).,NIHR Biomedical Research Centre, Clinical Research Facility, Guy’s and St Thomas NHS Foundation Trust, London, UK (K.O., A.R., P.J.C., A.M.S.)
| | - Ajay M. Shah
- School of Cardiovascular and Metabolic Medicine & Sciences, King’s College London British Heart Foundation Centre of Research Excellence, London, UK (K.O., A.R., R.R., P.J.C., A.M.S.).,NIHR Biomedical Research Centre, Clinical Research Facility, Guy’s and St Thomas NHS Foundation Trust, London, UK (K.O., A.R., P.J.C., A.M.S.)
| | - Aaron A. Phillips
- Departments of Physiology and Pharmacology, Clinical Neurosciences, Cardiac Sciences, Hotchkiss Brain Institute, Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Alberta, Canada (R.E.R, J.E.S., T.L., G.R.G., S.R.R., A.A.P.)
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Khadka N, Bikson M. Neurocapillary-Modulation. Neuromodulation 2022; 25:1299-1311. [PMID: 33340187 PMCID: PMC8213863 DOI: 10.1111/ner.13338] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 11/05/2020] [Accepted: 11/23/2020] [Indexed: 02/06/2023]
Abstract
OBJECTIVES We consider two consequences of brain capillary ultrastructure in neuromodulation. First, blood-brain barrier (BBB) polarization as a consequence of current crossing between interstitial space and the blood. Second, interstitial current flow distortion around capillaries impacting neuronal stimulation. MATERIALS AND METHODS We developed computational models of BBB ultrastructure morphologies to first assess electric field amplification at the BBB (principle 1) and neuron polarization amplification by the presence of capillaries (principle 2). We adapt neuron cable theory to develop an analytical solution for maximum BBB polarization sensitivity. RESULTS Electrical current crosses between the brain parenchyma (interstitial space) and capillaries, producing BBB electric fields (EBBB) that are >400x of the average parenchyma electric field (ĒBRAIN), which in turn modulates transport across the BBB. Specifically, for a BBB space constant (λBBB) and wall thickness (dth-BBB), the analytical solution for maximal BBB electric field (EABBB) is given as: (ĒBRAIN × λBBB)/dth-BBB. Electrical current in the brain parenchyma is distorted around brain capillaries, amplifying neuronal polarization. Specifically, capillary ultrastructure produces ∼50% modulation of the ĒBRAIN over the ∼40 μm inter-capillary distance. The divergence of EBRAIN (Activating function) is thus ∼100 kV/m2 per unit ĒBRAIN. CONCLUSIONS BBB stimulation by principle 1 suggests novel therapeutic strategies such as boosting metabolic capacity or interstitial fluid clearance. Whereas the spatial profile of EBRAIN is traditionally assumed to depend only on macroscopic anatomy, principle 2 suggests a central role for local capillary ultrastructure-which impact forms of neuromodulation including deep brain stimulation (DBS), spinal cord stimulation (SCS), transcranial magnetic stimulation (TMS), electroconvulsive therapy (ECT), and transcranial electrical stimulation (tES)/transcranial direct current stimulation (tDCS).
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Affiliation(s)
- Niranjan Khadka
- Department of Psychiatry, Laboratory for Neuropsychiatry and Neuromodulation, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Marom Bikson
- Department of Biomedical Engineering, The City College of New York, CUNY, New York, NY, USA.
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Ladthavorlaphatt K, Surti FBS, Beishon LC, Panerai RB, Robinson TG. Challenging neurovascular coupling through complex and variable duration cognitive paradigms: A subcomponent analysis. Med Eng Phys 2022; 110:103921. [PMID: 36564144 DOI: 10.1016/j.medengphy.2022.103921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 10/04/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022]
Abstract
A similar pattern of cerebral blood velocity (CBv) response has been observed for neurovascular coupling (NVC) assessment with cognitive tasks of varying complexity and duration. This lack of specificity could result from parallel changes in arterial blood pressure (BP) and PaCO2, which could confound the estimates of NVC integrity. Healthy participants (n = 16) underwent recordings at rest (5 min sitting) and during randomized paradigms of different complexity (naming words (NW) beginning with P-, R-, V- words and serial subtractions (SS) of 100-2, 100-7, 1000-17, with durations of 5, 30 and 60 s). Bilateral CBv (middle cerebral arteries, transcranial Doppler), end-tidal CO2 (EtCO2, capnography), blood pressure (BP, Finapres) and heart rate (HR, ECG) were recorded continuously. The bilateral CBv response to all paradigms was classified under objective criteria to select only responders, then the repeated data were averaged between visits. Bilateral CBv change to tasks was decomposed into the relative contributions (subcomponents) of arterial BP (VBP; neurogenic), critical closing pressure (VCrCP; metabolic) and resistance area product (VRAP; myogenic). A temporal effect was demonstrated in bilateral VBP and VRAP during all tasks (p<0.002), increased VBP early (between 0 and 10 s) and followed by decreases of VRAP late (25-35 s) in the response. VCrCP varied by complexity and duration (p<0.046). The main contributions to CBv responses to cognitive tasks of different complexity and duration were VBP and VRAP, whilst a smaller contribution from VCrCP would suggest sensitivity to metabolic demands. Further studies are needed to assess the influence of different paradigms, ageing and cerebrovascular conditions.
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Affiliation(s)
- Kannaphob Ladthavorlaphatt
- Department of Cardiovascular Sciences, College of Life Sciences, Leicester Royal Infirmary, University of Leicester, Level 4, Robert Kilpatrick Clinical Sciences Building, Leicester LE2 7LX, United Kingdom; Medical Diagnostics Unit, Thammasat University Hospital, Thammasat University, Pathumthani, Thailand.
| | - Farhaana B S Surti
- Department of Cardiovascular Sciences, College of Life Sciences, Leicester Royal Infirmary, University of Leicester, Level 4, Robert Kilpatrick Clinical Sciences Building, Leicester LE2 7LX, United Kingdom
| | - Lucy C Beishon
- Department of Cardiovascular Sciences, College of Life Sciences, Leicester Royal Infirmary, University of Leicester, Level 4, Robert Kilpatrick Clinical Sciences Building, Leicester LE2 7LX, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, College of Life Sciences, Leicester Royal Infirmary, University of Leicester, Level 4, Robert Kilpatrick Clinical Sciences Building, Leicester LE2 7LX, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, College of Life Sciences, Leicester Royal Infirmary, University of Leicester, Level 4, Robert Kilpatrick Clinical Sciences Building, Leicester LE2 7LX, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
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The ATP1A2 Mutation Associated with Hemiplegic Migraines: Case Report and Literature Review. CLINICAL AND TRANSLATIONAL NEUROSCIENCE 2022. [DOI: 10.3390/ctn6040025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Familial hemiplegic migraine type 2 is a premonitory subtype of migraine caused by an ATP1A2 gene mutation. It is an autosomal dominant genetic disease. Here, we report a 51-year-old woman who had a migraine attack due to a pathogenic ATP1A2 gene mutation. With frequent attacks, the patient developed complete left hemiplegia, a confusion of consciousness and partial seizures. Magnetic resonance imaging showed extensive angiogenic edema in the right cerebral hemisphere. In this article, we review the latest literature and try to explain the above symptoms in our patient with cortical spreading depression (CSD) and ATP1A2 gene mutations.
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González Méndez PP, Rodino Climent J, Stanley JA, Sitaram R. Real-Time fMRI Neurofeedback Training as a Neurorehabilitation Approach on Depressive Disorders: A Systematic Review of Randomized Control Trials. J Clin Med 2022; 11:jcm11236909. [PMID: 36498484 PMCID: PMC9737316 DOI: 10.3390/jcm11236909] [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: 10/17/2022] [Revised: 11/02/2022] [Accepted: 11/10/2022] [Indexed: 11/25/2022] Open
Abstract
Real-time functional magnetic resonance imaging neurofeedback (rt-fMRI-nf) training is an emerging intervention for neurorehabilitation. However, its translation into clinical use on participants with clinical depression is unclear, the effect estimates from randomized control trials and the certainty of the supporting evidence on the effect estimates are unknown. As the number of studies on neurofeedback increases every year, and better quality evidence becomes available, we evaluate the evidence of all randomized control trials available on the clinical application of rt-fMRI-nf training on participants with clinical depression. We performed electronic searches in Pubmed, Embase, CENTRAL, rtFIN database, Epistemonikos, trial registers, reference lists, other systematic reviews, conference abstracts, and cross-citation in Google Scholar. Reviewers independently selected studies, extracted data and evaluated the risk of bias. The certainty of the evidence was judged using the GRADE framework. This review complies with PRISMA guidelines and was submitted to PROSPERO registration. We found 435 results. After the selection process, we included 11 reports corresponding to four RCTs. The effect of rt-fMRI-nf on improving the severity of clinical depression scores demonstrated a tendency to favor the intervention; however, the general effect was not significant. At end of treatment, SMD (standardized mean difference): -0.32 (95% CI -0.73 to 0.10). At follow-up, SMD: -0.33 (95% CI -0.91, 1.25). All the studies showed changes in BOLD fMRI activation after training; however, only one study confirmed regulation success during a transfer run. Whole-brain analyses suggests that rt-fMRI nf may alter activity patterns in brain networks. More studies are needed to evaluate quality of life, acceptability, adverse effects, cognitive tasks, and physiology measures. We conclude that the current evidence on the effect of rt-fMRI-nf training for decision-making outcomes in patients with clinical depression is still based on low certainty of the evidence.
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Affiliation(s)
- Pamela P. González Méndez
- Department of Psychiatry, School of Medicine, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Correspondence: (P.P.G.M.); (R.S.)
| | - Julio Rodino Climent
- Brain Dynamics Laboratory, School of Biomedical Engineering, Universidad de Valparaíso, Valparaíso 2362905, Chile
| | - Jeffrey A. Stanley
- Department of Psychiatry and Behavioral Neurosciences, School of Medicine, Wayne State University, Detroit, MI 48202, USA
| | - Ranganatha Sitaram
- Diagnostic Imaging Department, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
- Correspondence: (P.P.G.M.); (R.S.)
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Mikkelsen ACD, Thomsen KL, Mookerjee RP, Hadjihambi A. The role of brain inflammation and abnormal brain oxygen homeostasis in the development of hepatic encephalopathy. Metab Brain Dis 2022; 38:1707-1716. [PMID: 36326976 DOI: 10.1007/s11011-022-01105-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/10/2022] [Indexed: 11/06/2022]
Abstract
Hepatic encephalopathy (HE) is a frequent complication of chronic liver disease (CLD) and has a complex pathogenesis. Several preclinical and clinical studies have reported the presence of both peripheral and brain inflammation in CLD and their potential impact in the development of HE. Altered brain vascular density and tone, as well as compromised cerebral and systemic blood flow contributing to the development of brain hypoxia, have also been reported in animal models of HE, while a decrease in cerebral metabolic rate of oxygen and cerebral blood flow has consistently been observed in patients with HE. Whilst significant strides in our understanding have been made over the years, evaluating all these mechanistic elements in vivo and showing causal association with development of HE, have been limited through the practical constraints of experimentation. Nonetheless, improvements in non-invasive assessments of different neurophysiological parameters, coupled with techniques to assess changes in inflammatory and metabolic pathways, will help provide more granular insights on these mechanisms. In this special issue we discuss some of the emerging evidence supporting the hypothesis that brain inflammation and abnormal oxygen homeostasis occur interdependently during CLD and comprise important contributors to the development of HE. This review aims at furnishing evidence for further research in brain inflammation and oxygen homeostasis as additional therapeutic targets and potentially diagnostic markers for HE.
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Affiliation(s)
| | - Karen Louise Thomsen
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
- UCL Institute of Liver and Digestive Health, University College London, London, UK
| | - Rajeshwar Prosad Mookerjee
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
- UCL Institute of Liver and Digestive Health, University College London, London, UK
| | - Anna Hadjihambi
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, SE5 9NT, UK.
- Faculty of Life Sciences and Medicine, King's College London, London, UK.
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44
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Drew PJ. Neurovascular coupling: motive unknown. Trends Neurosci 2022; 45:809-819. [PMID: 35995628 PMCID: PMC9768528 DOI: 10.1016/j.tins.2022.08.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/01/2022] [Accepted: 08/05/2022] [Indexed: 12/13/2022]
Abstract
In the brain, increases in neural activity drive changes in local blood flow via neurovascular coupling. The common explanation for increased blood flow (known as functional hyperemia) is that it supplies the metabolic needs of active neurons. However, there is a large body of evidence that is inconsistent with this idea. Baseline blood flow is adequate to supply oxygen needs even with elevated neural activity. Neurovascular coupling is irregular, absent, or inverted in many brain regions, behavioral states, and conditions. Increases in respiration can increase brain oxygenation without flow changes. Simulations show that given the architecture of the brain vasculature, areas of low blood flow are inescapable and cannot be removed by functional hyperemia. As discussed in this article, potential alternative functions of neurovascular coupling include supplying oxygen for neuromodulator synthesis, brain temperature regulation, signaling to neurons, stabilizing and optimizing the cerebral vascular structure, accommodating the non-Newtonian nature of blood, and driving the production and circulation of cerebrospinal fluid (CSF).
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Affiliation(s)
- Patrick J Drew
- Center for Neural Engineering, Departments of Engineering Science and Mechanics, Neurosurgery, Biology, and Biomedical Engineering, The Pennsylvania State University, W-317 Millennium Science Complex, University Park, PA 16802, USA.
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Aksenov DP, Doubovikov ED, Serdyukova NA, Gascoigne DA, Linsenmeier RA, Drobyshevsky A. Brain tissue oxygen dynamics while mimicking the functional deficiency of interneurons. Front Cell Neurosci 2022; 16:983298. [PMID: 36339824 PMCID: PMC9630360 DOI: 10.3389/fncel.2022.983298] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/06/2022] [Indexed: 11/13/2022] Open
Abstract
The dynamic interaction between excitatory and inhibitory activity in the brain is known as excitatory-inhibitory balance (EIB). A significant shift in EIB toward excitation has been observed in numerous pathological states and diseases, such as autism or epilepsy, where interneurons may be dysfunctional. The consequences of this on neurovascular interactions remains to be elucidated. Specifically, it is not known if there is an elevated metabolic consumption of oxygen due to increased excitatory activity. To investigate this, we administered microinjections of picrotoxin, a gamma aminobutyric acid (GABA) antagonist, to the rabbit cortex in the awake state to mimic the functional deficiency of GABAergic interneurons. This caused an observable shift in EIB toward excitation without the induction of seizures. We used chronically implanted electrodes to measure both neuronal activity and brain tissue oxygen concentrations (PO2) simultaneously and in the same location. Using a high-frequency recording rate for PO2, we were able to detect two important phenomena, (1) the shift in EIB led to a change in the power spectra of PO2 fluctuations, such that higher frequencies (8-15 cycles per minute) were suppressed and (2) there were brief periods (dips with a duration of less than 100 ms associated with neuronal bursts) when PO2 dropped below 10 mmHg, which we defined as the threshold for hypoxia. The dips were followed by an overshoot, which indicates either a rapid vascular response or decrease in oxygen consumption. Our results point to the essential role of interneurons in brain tissue oxygen regulation in the resting state.
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Affiliation(s)
- Daniil P. Aksenov
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, United States,Department of Anesthesiology, NorthShore University HealthSystem, Evanston, IL, United States,Pritzker School of Medicine, University of Chicago, Chicago, IL, United States,*Correspondence: Daniil P. Aksenov,
| | - Evan D. Doubovikov
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, United States
| | - Natalya A. Serdyukova
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States,Department of Pediatrics, NorthShore University HealthSystem, Evanston, IL, United States
| | - David A. Gascoigne
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, United States
| | - Robert A. Linsenmeier
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States
| | - Alexander Drobyshevsky
- Pritzker School of Medicine, University of Chicago, Chicago, IL, United States,Department of Pediatrics, NorthShore University HealthSystem, Evanston, IL, United States
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46
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Schmithorst VJ, Adams PS, Badaly D, Lee VK, Wallace J, Beluk N, Votava-Smith JK, Weinberg JG, Beers SR, Detterich J, Wood JC, Lo CW, Panigrahy A. Impaired Neurovascular Function Underlies Poor Neurocognitive Outcomes and Is Associated with Nitric Oxide Bioavailability in Congenital Heart Disease. Metabolites 2022; 12:metabo12090882. [PMID: 36144286 PMCID: PMC9504090 DOI: 10.3390/metabo12090882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 09/14/2022] [Accepted: 09/15/2022] [Indexed: 12/03/2022] Open
Abstract
We use a non-invasive MRI proxy of neurovascular function (pnvf) to assess the ability of the vasculature to supply baseline metabolic demand, to compare pediatric and young adult congenital heart disease (CHD) patients to normal referents and relate the proxy to neurocognitive outcomes and nitric oxide bioavailability. In a prospective single-center study, resting-state blood-oxygen-level-dependent (BOLD) and arterial spin labeling (ASL) MRI scans were successfully obtained from 24 CHD patients (age = 15.4 ± 4.06 years) and 63 normal referents (age = 14.1 ± 3.49) years. Pnvf was computed on a voxelwise basis as the negative of the ratio of functional connectivity strength (FCS) estimated from the resting-state BOLD acquisition to regional cerebral blood flow (rCBF) as estimated from the ASL acquisition. Pnvf was used to predict end-tidal CO2 (PETCO2) levels and compared to those estimated from the BOLD data. Nitric oxide availability was obtained via nasal measurements (nNO). Pnvf was compared on a voxelwise basis between CHD patients and normal referents and correlated with nitric oxide availability and neurocognitive outcomes as assessed via the NIH Toolbox. Pnvf was shown as highly predictive of PETCO2 using theoretical modeling. Pnvf was found to be significantly reduced in CHD patients in default mode network (DMN, comprising the ventromedial prefrontal cortex and posterior cingulate/precuneus), salience network (SN, comprising the insula and dorsal anterior cingulate), and central executive network (CEN, comprising posterior parietal and dorsolateral prefrontal cortex) regions with similar findings noted in single cardiac ventricle patients. Positive correlations of Pnvf in these brain regions, as well as the hippocampus, were found with neurocognitive outcomes. Similarly, positive correlations between Pnvf and nitric oxide availability were found in frontal DMN and CEN regions, with particularly strong correlations in subcortical regions (putamen). Reduced Pnvf in CHD patients was found to be mediated by nNO. Mediation analyses further supported that reduced Pnvf in these regions underlies worse neurocognitive outcome in CHD patients and is associated with nitric oxide bioavailability. Impaired neuro-vascular function, which may be non-invasively estimated via combined arterial-spin label and BOLD MR imaging, is a nitric oxide bioavailability dependent factor implicated in adverse neurocognitive outcomes in pediatric and young adult CHD.
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Affiliation(s)
| | - Phillip S. Adams
- Department of Pediatric Anesthesiology, UPMC Children’s Hospital, Pittsburgh, PA 15224, USA
| | - Daryaneh Badaly
- Learning and Development Center, Child Mind Institute, New York, NY 10022, USA
| | - Vincent K. Lee
- Department of Pediatric Radiology, UPMC Children’s Hospital, Pittsburgh, PA 15224, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Julia Wallace
- Department of Pediatric Radiology, UPMC Children’s Hospital, Pittsburgh, PA 15224, USA
| | - Nancy Beluk
- Department of Pediatric Radiology, UPMC Children’s Hospital, Pittsburgh, PA 15224, USA
| | | | | | - Sue R. Beers
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Jon Detterich
- Heart Institute, Children’s Hospital Los Angeles, Los Angeles, CA 90027, USA
| | - John C. Wood
- Heart Institute, Children’s Hospital Los Angeles, Los Angeles, CA 90027, USA
| | - Cecilia W. Lo
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, PA 15213, USA
| | - Ashok Panigrahy
- Department of Pediatric Radiology, UPMC Children’s Hospital, Pittsburgh, PA 15224, USA
- Department of Radiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Correspondence: ; Tel.: +1-412-692-5510; Fax: +1-412-692-6929
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47
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Kim KS, Jeon MT, Kim ES, Lee CH, Kim DG. Activation of NMDA receptors in brain endothelial cells increases transcellular permeability. Fluids Barriers CNS 2022; 19:70. [PMID: 36068542 PMCID: PMC9450318 DOI: 10.1186/s12987-022-00364-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 08/15/2022] [Indexed: 12/04/2022] Open
Abstract
Neurovascular coupling is a precise mechanism that induces increased blood flow to activated brain regions, thereby providing oxygen and glucose. In this study, we hypothesized that N-methyl-D-aspartate (NMDA) receptor signaling, the most well characterized neurotransmitter signaling system which regulates delivery of essential molecules through the blood–brain barrier (BBB). Upon application of NMDA in both in vitro and in vivo models, increased delivery of bioactive molecules that was mediated through modulation of molecules involved in molecular delivery, including clathrin and caveolin were observed. Also, NMDA activation induced structural changes in the BBB and increased transcellular permeability that showed regional heterogeneity in its responses. Moreover, NMDA receptor activation increased endosomal trafficking and facilitated inactivation of lysosomal pathways and consequently increased molecular delivery mediated by activation of calmodulin-dependent protein kinase II (CaMKII) and RhoA/protein kinase C (PKC). Subsequent in vivo experiments using mice specifically lacking NMDA receptor subunit 1 in endothelial cells showed decreased neuronal density in the brain cortex, suggesting that a deficiency in NMDA receptor signaling in brain endothelial cells induces neuronal losses. Together, these results highlight the importance of NMDA-receptor-mediated signaling in the regulation of BBB permeability that surprisingly also affected CD31 staining.
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Affiliation(s)
- Kyu-Sung Kim
- Neuroimmunology Lab, Dementia Research Group, Korea Brain Research Institute, Daegu, 41062, South Korea.,Department of Brain Science, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, South Korea
| | - Min Tae Jeon
- Neuroimmunology Lab, Dementia Research Group, Korea Brain Research Institute, Daegu, 41062, South Korea
| | - Eun Seon Kim
- Neuroimmunology Lab, Dementia Research Group, Korea Brain Research Institute, Daegu, 41062, South Korea.,Department of Brain Science, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, South Korea
| | - Chan Hee Lee
- Neuroimmunology Lab, Dementia Research Group, Korea Brain Research Institute, Daegu, 41062, South Korea
| | - Do-Geun Kim
- Neuroimmunology Lab, Dementia Research Group, Korea Brain Research Institute, Daegu, 41062, South Korea.
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48
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Lundberg JO, Weitzberg E. Nitric oxide signaling in health and disease. Cell 2022; 185:2853-2878. [DOI: 10.1016/j.cell.2022.06.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 06/01/2022] [Accepted: 06/06/2022] [Indexed: 10/16/2022]
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49
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Hadjihambi A, Cudalbu C, Pierzchala K, Simicic D, Donnelly C, Konstantinou C, Davies N, Habtesion A, Gourine AV, Jalan R, Hosford PS. Abnormal brain oxygen homeostasis in an animal model of liver disease. JHEP Rep 2022; 4:100509. [PMID: 35865351 PMCID: PMC9293761 DOI: 10.1016/j.jhepr.2022.100509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 04/23/2022] [Accepted: 05/10/2022] [Indexed: 01/15/2023] Open
Abstract
Background & Aims Increased plasma ammonia concentration and consequent disruption of brain energy metabolism could underpin the pathogenesis of hepatic encephalopathy (HE). Brain energy homeostasis relies on effective maintenance of brain oxygenation, and dysregulation impairs neuronal function leading to cognitive impairment. We hypothesised that HE is associated with reduced brain oxygenation and we explored the potential role of ammonia as an underlying pathophysiological factor. Methods In a rat model of chronic liver disease with minimal HE (mHE; bile duct ligation [BDL]), brain tissue oxygen measurement, and proton magnetic resonance spectroscopy were used to investigate how hyperammonaemia impacts oxygenation and metabolic substrate availability in the central nervous system. Ornithine phenylacetate (OP, OCR-002; Ocera Therapeutics, CA, USA) was used as an experimental treatment to reduce plasma ammonia concentration. Results In BDL animals, glucose, lactate, and tissue oxygen concentration in the cerebral cortex were significantly lower than those in sham-operated controls. OP treatment corrected the hyperammonaemia and restored brain tissue oxygen. Although BDL animals were hypotensive, cortical tissue oxygen concentration was significantly improved by treatments that increased arterial blood pressure. Cerebrovascular reactivity to exogenously applied CO2 was found to be normal in BDL animals. Conclusions These data suggest that hyperammonaemia significantly decreases cortical oxygenation, potentially compromising brain energy metabolism. These findings have potential clinical implications for the treatment of patients with mHE. Lay summary Brain dysfunction is a serious complication of cirrhosis and affects approximately 30% of these patients; however, its treatment continues to be an unmet clinical need. This study shows that oxygen concentration in the brain of an animal model of cirrhosis is markedly reduced. Low arterial blood pressure and increased ammonia (a neurotoxin that accumulates in patients with liver failure) are shown to be the main underlying causes. Experimental correction of these abnormalities restored oxygen concentration in the brain, suggesting potential therapeutic avenues to explore.
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Key Words
- 1H-MRS, proton magnetic resonance spectroscopy
- AIT, Animal Imaging and Technology
- ALT, alanine transaminase
- ATZ, acetazolamide
- Ala, alanine
- Asc, ascorbate
- Asp, aspartate
- BDL, bile duct ligation
- BOLD, blood oxygen level dependent
- BP, blood pressure
- CBF, cerebral blood flow
- CIBM, Center for Biomedical Imaging
- CLD, chronic liver disease
- CMRO2, cerebral metabolic rate of oxygen
- CNS, central nervous system
- Chronic liver disease
- Cr, creatine
- EPFL, Ecole Polytechnique Fédérale de Lausanne
- GABA, γ-aminobutyric acid
- GPC, glycerophosphocholine
- GSH, glutathione
- Glc, glucose
- Gln, glutamine
- Glu, glutamate
- HE, hepatic encephalopathy
- Hyperammonaemia
- Ins, myo-inositol
- Lac, lactate
- MAP, mean arterial pressure
- NAA, N acetylaspartate
- NO, nitric oxide
- OP, ornithine phenylacetate
- Ornithine phenylacetate
- Oxygen
- PCho, phosphocholine
- PCr, phosphocreatine
- PE, phenylephrine
- Phenylephrine
- SPECIAL, spin echo full intensity acquired localised
- TE, echo time
- Tau, taurine
- VOI, volume of interest
- [18F]-FDG PET, [18F]-fluorodeoxyglucose positron emission tomography
- eNOS, endothelial nitric oxide synthase
- fMRI, functional magnetic resonance imaging
- hepatic encephalopathy
- mHE, minimal HE
- pCO2, partial pressure of carbon dioxide
- pO2, partial pressure of oxygen
- tCho, total choline
- tCr, total creatine
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Affiliation(s)
- Anna Hadjihambi
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, Rowland Hill Street, London, UK
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, UK
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK
- Faculty of Life Sciences and Medicine, King’s College London, London, UK
| | - Cristina Cudalbu
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Katarzyna Pierzchala
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
- Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Dunja Simicic
- CIBM Center for Biomedical Imaging, Lausanne, Switzerland
- Animal Imaging and Technology, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Chris Donnelly
- Institute of Sports Science and Department of Physiology, University of Lausanne, Lausanne, Switzerland
| | - Christos Konstantinou
- The Roger Williams Institute of Hepatology London, Foundation for Liver Research, London, UK
- Faculty of Life Sciences and Medicine, King’s College London, London, UK
| | - Nathan Davies
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, Rowland Hill Street, London, UK
| | - Abeba Habtesion
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, Rowland Hill Street, London, UK
| | - Alexander V. Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Rajiv Jalan
- UCL Institute for Liver and Digestive Health, Division of Medicine, UCL Medical School, Royal Free Hospital, Rowland Hill Street, London, UK
- European Foundation for the Study of Chronic Liver Failure
| | - Patrick S. Hosford
- Centre for Cardiovascular and Metabolic Neuroscience, Neuroscience, Physiology and Pharmacology, University College London, London, UK
- William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, London, UK
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50
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Gourine AV, Dale N. Brain H + /CO 2 sensing and control by glial cells. Glia 2022; 70:1520-1535. [PMID: 35102601 DOI: 10.1002/glia.24152] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 01/11/2022] [Accepted: 01/17/2022] [Indexed: 01/04/2023]
Abstract
Maintenance of constant brain pH is critically important to support the activity of individual neurons, effective communication within the neuronal circuits, and, thus, efficient processing of information by the brain. This review article focuses on how glial cells detect and respond to changes in brain tissue pH and concentration of CO2 , and then trigger systemic and local adaptive mechanisms that ensure a stable milieu for the operation of brain circuits. We give a detailed account of the cellular and molecular mechanisms underlying sensitivity of glial cells to H+ and CO2 and discuss the role of glial chemosensitivity and signaling in operation of three key mechanisms that work in concert to keep the brain pH constant. We discuss evidence suggesting that astrocytes and marginal glial cells of the brainstem are critically important for central respiratory CO2 chemoreception-a fundamental physiological mechanism that regulates breathing in accord with changes in blood and brain pH and partial pressure of CO2 in order to maintain systemic pH homeostasis. We review evidence suggesting that astrocytes are also responsible for the maintenance of local brain tissue extracellular pH in conditions of variable acid loads associated with changes in the neuronal activity and metabolism, and discuss potential role of these glial cells in mediating the effects of CO2 on cerebral vasculature.
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Affiliation(s)
- Alexander V Gourine
- Centre for Cardiovascular and Metabolic Neuroscience, Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Nicholas Dale
- School of Life Sciences, University of Warwick, Coventry, UK
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