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Talbot JS, Perkins DR, Dawkins TG, Douglas AJM, Griffiths TD, Richards CT, Owen K, Lord RN, Pugh CJA, Oliver JL, Lloyd RS, Ainslie PN, McManus AM, Stembridge M. Neurovascular coupling and cerebrovascular hemodynamics are modified by exercise training status at different stages of maturation during youth. Am J Physiol Heart Circ Physiol 2023; 325:H510-H521. [PMID: 37450291 PMCID: PMC10538977 DOI: 10.1152/ajpheart.00302.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/10/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Neurovascular coupling (NVC) is mediated via nitric oxide signaling, which is independently influenced by sex hormones and exercise training. Whether exercise training differentially modifies NVC pre- versus postpuberty, where levels of circulating sex hormones will differ greatly within and between sexes, remains to be determined. Therefore, we investigated the influence of exercise training status on resting intracranial hemodynamics and NVC at different stages of maturation. Posterior and middle cerebral artery velocities (PCAv and MCAv) and pulsatility index (PCAPI and MCAPI) were assessed via transcranial Doppler ultrasound at rest and during visual NVC stimuli. N = 121 exercise-trained (males, n = 32; females, n = 32) and untrained (males, n = 28; females, n = 29) participants were characterized as pre (males, n = 33; females, n = 29)- or post (males, n = 27; females, n = 32)-peak height velocity (PHV). Exercise-trained youth demonstrated higher resting MCAv (P = 0.010). Maturity and training status did not affect the ΔPCAv and ΔMCAv during NVC. However, pre-PHV untrained males (19.4 ± 13.5 vs. 6.8 ± 6.0%; P ≤ 0.001) and females (19.3 ± 10.8 vs. 6.4 ± 7.1%; P ≤ 0.001) had a higher ΔPCAPI during NVC than post-PHV untrained counterparts, whereas the ΔPCAPI was similar in pre- and post-PHV trained youth. Pre-PHV untrained males (19.4 ± 13.5 vs. 7.9 ± 6.0%; P ≤ 0.001) and females (19.3 ± 10.8 vs. 11.1 ± 7.3%; P = 0.016) also had a larger ΔPCAPI than their pre-PHV trained counterparts during NVC, but the ΔPCAPI was similar in trained and untrained post-PHV youth. Collectively, our data indicate that exercise training elevates regional cerebral blood velocities during youth, but training-mediated adaptations in NVC are only attainable during early stages of adolescence. Therefore, childhood provides a unique opportunity for exercise-mediated adaptations in NVC.NEW & NOTEWORTHY We report that the change in cerebral blood velocity during a neurovascular coupling task (NVC) is similar in pre- and postpubertal youth, regardless of exercise-training status. However, prepubertal untrained youth demonstrated a greater increase in cerebral blood pulsatility during the NVC task when compared with their trained counterparts. Our findings highlight that childhood represents a unique opportunity for exercise-mediated adaptations in cerebrovascular hemodynamics during NVC, which may confer long-term benefits in cerebrovascular function.
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Affiliation(s)
- Jack S Talbot
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Dean R Perkins
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Tony G Dawkins
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Andrew J M Douglas
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Thomas D Griffiths
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Cory T Richards
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Kerry Owen
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Windsor Clive Primary School, Cardiff, United Kingdom
| | - Rachel N Lord
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Christopher J A Pugh
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Jon L Oliver
- Youth Physical Development Centre, Cardiff Metropolitan University, Cardiff, United Kingdom
- Sports Performance Research Institute New Zealand, AUT University, Auckland, New Zealand
| | - Rhodri S Lloyd
- Youth Physical Development Centre, Cardiff Metropolitan University, Cardiff, United Kingdom
- Sports Performance Research Institute New Zealand, AUT University, Auckland, New Zealand
- Centre for Sport Science and Human Performance, Waikato Institute of Technology, Waikato, New Zealand
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Ali M McManus
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
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Burma JS, Wassmuth RM, Kennedy CM, Miutz LN, Newel KT, Carere J, Smirl JD. Does task complexity impact the neurovascular coupling response similarly between males and females? Physiol Rep 2021; 9:e15020. [PMID: 34514743 PMCID: PMC8436054 DOI: 10.14814/phy2.15020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 08/10/2021] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND While previous studies have demonstrated a complex visual scene search elicits a robust neurovascular coupling (NVC) response, it is unknown how the duration of visual stimuli presentation influences NVC metrics. This study examined how stimuli duration, in addition to biological sex and self-reported engagement impact NVC responses. METHODS Participants (n = 20, female = 10) completed four visual paradigms. Three involved simple visual shapes presented at 0.5-, 2-, and 4-s intervals in randomized orders. The fourth paradigm was a complex visual scene search ("Where's Waldo?"). Participants completed eight cycles of 20-s eyes-closed followed by 40-s eyes-open. Transcranial Doppler ultrasound indexed posterior and middle cerebral artery velocities (PCA and MCA). Participants self-reported their engagement following each task (1 [minimal] to 10 [maximal]). RESULTS The "Where's Waldo?" task evoked greater PCA percent increase (all p < 0.001) and area under the curve during the first 30-s of the task (all p < 0.001) compared to simple shapes. Females displayed greater absolute baseline and peak PCA and MCA velocities across all tasks (all p < 0.002). Subjective engagement displayed moderate correlation levels with PCA percent increase (Spearman ρ = 0.58) and area under the curve (Spearman ρ = 0.60) metrics in males, whereas these were weak for females (Spearman ρ = 0.43 and ρ = 0.38, respectively). CONCLUSIONS The complex visual paradigm "Where's Waldo?" greatly augmented the signal-to-noise ratio within the PCA aspects of the NVC response compared to simple shapes. While both sexes had similar NVC responses, task engagement was more related to NVC metrics in males compared to females. Therefore, future NVC investigations should consider task engagement when designing studies.
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Burma JS, Macaulay A, Copeland PV, Khatra O, Bouliane KJ, Smirl JD. Temporal evolution of neurovascular coupling recovery following moderate- and high-intensity exercise. Physiol Rep 2021; 9:e14695. [PMID: 33463899 PMCID: PMC7814491 DOI: 10.14814/phy2.14695] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/24/2020] [Accepted: 12/01/2020] [Indexed: 01/13/2023] Open
Abstract
PURPOSE Studies examining neurovascular coupling (NVC) require participants to refrain from exercise for 12-24 hours. However, there is a paucity of empirical evidence for this restriction. The objectives for this study were to delineate the time-course recovery of NVC metrics following exercise and establish the NVC within- and between-day reliability. METHODS Nine participants completed a complex visual search paradigm to assess NVC via transcranial Doppler ultrasound of the posterior cerebral artery blood velocity (PCA). Measurements were performed prior to and throughout the 8-hour recovery period following three randomized conditions: 45 minutes of moderate-intensity exercise (at 50% heart-rate reserve), 30 minutes high-intensity intervals (10, 1-minute intervals at 85% heart-rate reserve), and control (30 minutes quiet rest). In each condition, baseline measures were collected at 8:00am with serial follow-ups at hours zero, one, two, four, six, and eight. RESULTS Area-under-the-curve and time-to-peak PCA velocity during the visual search were attenuated at hour zero following high-intensity intervals (all p < 0.05); however, these NVC metrics recovered at hour one (all p > 0.13). Conversely, baseline PCA velocity, peak PCA velocity, and the relative percent increase were not different following high-intensity intervals compared to baseline (all p > 0.26). No NVC metrics differed from baseline following both moderate exercise and control conditions (all p > 0.24). The majority of the NVC parameters demonstrated high levels of reliability (intraclass correlation coefficient: >0.90). CONCLUSION Future NVC assessments can take place a minimum of one hour following exercise. Moreover, all metrics did not change across the control condition, therefore future studies using this methodology can reliably quantify NVC between 8:00am and 7:00 pm.
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Affiliation(s)
- Joel S. Burma
- Concussion Research LaboratoryFaculty of Health and Exercise ScienceUniversity of British ColumbiaKelownaBCCanada
- Sport Injury Prevention Research CentreFaculty of KinesiologyUniversity of CalgaryCalgaryABCanada
- Human Performance LaboratoryFaculty of KinesiologyUniversity of CalgaryCalgaryABCanada
- Hotchkiss Brain InstituteUniversity of CalgaryCalgaryABCanada
- Alberta Children’s Hospital Research InstituteUniversity of CalgaryCalgaryABCanada
- Libin Cardiovascular Institute of AlbertaUniversity of CalgaryABCanada
| | - Alannah Macaulay
- Concussion Research LaboratoryFaculty of Health and Exercise ScienceUniversity of British ColumbiaKelownaBCCanada
- School of Health Sciences, Nuclear MedicineBritish Columbia Institute of TechnologyBurnabyBCCanada
| | - Paige V. Copeland
- Concussion Research LaboratoryFaculty of Health and Exercise ScienceUniversity of British ColumbiaKelownaBCCanada
| | - Omeet Khatra
- Faculty of MedicineUniversity of British ColumbiaVancouverBCCanada
| | - Kevin J. Bouliane
- Concussion Research LaboratoryFaculty of Health and Exercise ScienceUniversity of British ColumbiaKelownaBCCanada
| | - Jonathan D. Smirl
- Concussion Research LaboratoryFaculty of Health and Exercise ScienceUniversity of British ColumbiaKelownaBCCanada
- Sport Injury Prevention Research CentreFaculty of KinesiologyUniversity of CalgaryCalgaryABCanada
- Human Performance LaboratoryFaculty of KinesiologyUniversity of CalgaryCalgaryABCanada
- Hotchkiss Brain InstituteUniversity of CalgaryCalgaryABCanada
- Alberta Children’s Hospital Research InstituteUniversity of CalgaryCalgaryABCanada
- Libin Cardiovascular Institute of AlbertaUniversity of CalgaryABCanada
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Smirl JD, Peacock D, Wright AD, Bouliane KJ, Dierijck J, Burma JS, Kennefick M, Wallace C, van Donkelaar P. An Acute Bout of Soccer Heading Subtly Alters Neurovascular Coupling Metrics. Front Neurol 2020; 11:738. [PMID: 32849205 PMCID: PMC7396491 DOI: 10.3389/fneur.2020.00738] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/16/2020] [Indexed: 01/22/2023] Open
Abstract
Objective: The current investigation examined how a bout of soccer heading may impact brain function. Design: Semi-randomized crossover cohort. Setting: Controlled soccer heading. Participants: Seven male soccer players (24.1 ± 1.5 years). Intervention: 40 successful soccer headers were performed in 20 min (25 m, launch velocity ~80 km/h). X2 xPatch recorded linear and rotational head accelerations during each impact. A contact control “sham” condition – ball made body contact, but not by the head; and a no activity time “control” condition were also completed. Main Outcome Measures: Posterior and middle cerebral artery (PCA and MCA, respectively), cerebral blood velocity (CBV) was recorded during a visual task (neurovascular coupling: NVC) alongside SCAT3 symptoms scores pre/post a controlled bout of soccer heading. Results: Cumulative linear and rotational accelerations were 1,574 ± 97.9 g and 313,761 ± 23,966 rads/s2, respectively, during heading and changes in SCAT3 symptom number (pre: 2.6 ± 3.0; post: 6.7 ± 6.2, p = 0.13) and severity (pre: 3.7 ± 3.6, post: 9.4 ± 7.6, p = 0.11) were unchanged. In the PCA, no NVC differences were observed, including: relative CBV increase (28.0 ± 7.6%, p = 0.71) and total activation (188.7 ± 68.1 cm, p = 0.93). However, MCA-derived NVC metrics were blunted following heading, demonstrating decreased relative CBV increase (7.8 ± 3.1%, p = 0.03) and decreased total activation (26.7 ± 45.3 cm, p = 0.04). Conclusion: Although an acute bout of soccer heading did not result in an increase of concussion-like symptoms, there were alterations in NVC responses within the MCA during a visual task. This suggests an acute bout of repetitive soccer heading can alter CBV regulation within the region of the brain associated with the header impacts.
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Affiliation(s)
- Jonathan D Smirl
- Concussion Research Laboratory, University of British Columbia, Kelowna, BC, Canada.,Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.,Sport Injury Prevention Research Centre, University of Calgary, Calgary, AB, Canada.,Human Performance Laboratory, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, AB, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.,Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada
| | - Dakota Peacock
- Southern Medical Program, University of British Columbia, Kelowna, BC, Canada
| | - Alexander D Wright
- Concussion Research Laboratory, University of British Columbia, Kelowna, BC, Canada.,Southern Medical Program, University of British Columbia, Kelowna, BC, Canada.,MD/PhD Program, University of British Columbia, Vancouver, BC, Canada.,Experimental Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Kevin J Bouliane
- Concussion Research Laboratory, University of British Columbia, Kelowna, BC, Canada
| | - Jill Dierijck
- Concussion Research Laboratory, University of British Columbia, Kelowna, BC, Canada.,Faculty of Health, School of Physiotherapy, Dalhousie University, Halifax, NS, Canada
| | - Joel S Burma
- Concussion Research Laboratory, University of British Columbia, Kelowna, BC, Canada.,Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.,Sport Injury Prevention Research Centre, University of Calgary, Calgary, AB, Canada.,Human Performance Laboratory, University of Calgary, Calgary, AB, Canada
| | - Michael Kennefick
- Concussion Research Laboratory, University of British Columbia, Kelowna, BC, Canada
| | - Colin Wallace
- Concussion Research Laboratory, University of British Columbia, Kelowna, BC, Canada
| | - Paul van Donkelaar
- Concussion Research Laboratory, University of British Columbia, Kelowna, BC, Canada
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An objective method to identify non-responders in neurovascular coupling testing. J Neurosci Methods 2020; 341:108779. [DOI: 10.1016/j.jneumeth.2020.108779] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/10/2020] [Accepted: 05/11/2020] [Indexed: 01/04/2023]
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Wright AD, Smirl JD, Bryk K, Jakovac M, van Donkelaar P. A Prospective Transcranial Doppler Ultrasound-Based Evaluation of the Effects of Repetitive Subconcussive Head Trauma on Neurovascular Coupling Dynamics. Clin J Sport Med 2020; 30 Suppl 1:S53-S60. [PMID: 32132478 DOI: 10.1097/jsm.0000000000000578] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine the effects of repetitive subconcussive head trauma on neurovascular coupling (NVC) responses. DESIGN Prospective cohort study collected between September 2013 and December 2016. SETTING University laboratory. PARTICIPANTS One hundred seventy-nine elite, junior-level (age, 19.6 ± 1.5 years) contact sport (ice hockey, American football) athletes recruited for preseason testing. Fifty-two nonconcussed athletes returned for postseason testing. Fifteen noncontact sport athletes (age, 20.4 ± 2.2 years) also completed preseason and postseason testing. EXPOSURE(S) Subconcussive sport-related head trauma. MAIN OUTCOME MEASURES Dynamics of NVC were estimated during cycles of 20 seconds eyes closed and 40 seconds eyes open to a visual stimulus (reading) by measuring cerebral blood flow (CBF) velocity in the posterior (PCA) and middle (MCA) cerebral arteries via transcranial Doppler ultrasound. RESULTS Both athlete groups demonstrated no significant differences in PCA or MCA NVC dynamics between preseason and postseason, despite exposure to a median of 353.5 (range, 295.0-587.3) head impacts (>2g) over the course of the season for contact sport athletes. CONCLUSIONS Within the context of growing concern over detrimental effects of repetitive subconcussive trauma, the current results encouragingly suggest that the dynamics of NVC responses are not affected by 1 season of participation in junior-level ice hockey or American football. This is an important finding because it indicates an appropriate postseason CBF response to elevated metabolic demand with increases in neural activity.
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Affiliation(s)
- Alexander D Wright
- MD/PhD Program, University of British Columbia, Vancouver, BC, Canada
- Southern Medical Program, Reichwald Health Sciences Centre, University of British Columbia Okanagan, Kelowna, BC, Canada
- Experimental Medicine Program, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada; and
| | - Jonathan D Smirl
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada; and
| | - Kelsey Bryk
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada; and
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE
| | - Michael Jakovac
- Southern Medical Program, Reichwald Health Sciences Centre, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Paul van Donkelaar
- School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada; and
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Beishon L, Williams CAL, Robinson TG, Haunton VJ, Panerai RB. Neurovascular coupling response to cognitive examination in healthy controls: a multivariate analysis. Physiol Rep 2018; 6:e13803. [PMID: 30033685 PMCID: PMC6055030 DOI: 10.14814/phy2.13803] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/24/2018] [Indexed: 12/21/2022] Open
Abstract
Cognitive testing with transcranial Doppler ultrasonography (TCD) has been used to assess neurovascular coupling (NVC), but few studies address its multiple contributions. Subcomponent analysis considers the relative myogenic (resistance area product, RAP) and metabolic (critical closing pressure (CrCP)) contributors. The aim of this study was to investigate the changes in subcomponents that occur with cognitive stimulation with the Addenbrooke's Cognitive Examination (ACE-III) in healthy controls. Healthy volunteers underwent continuous recording of bilateral TCD, heart rate (HR, three-lead ECG), end-tidal CO2 (ETCO2 , capnography), and mean arterial pressure (MAP, Finometer). The study comprised a 5-min baseline recording, followed by all 20 paradigms from the ACE-III. The cerebral blood flow velocity (CBFv) response was decomposed into the relative contributions (subcomponents); VBP (MAP), VCrCP (CrCP), and VRAP (RAP). Data are presented as peak population normalized mean changes from baseline, and median area under the curve (AUC). Forty bilateral datasets were obtained (27 female, 37 right hand dominant). VBP increased at task initiation in all paradigms but differed between tasks (range (SD): 4.06 (8.92)-16.04 (12.23) %, P < 0.05). HR, but not ETCO2 , also differed significantly (P < 0.05). Changes in VRAP reflected changes in MAP, but in some paradigms atypical responses were seen. VCrCP AUC varied significantly within paradigm sections (range [SD]: 18.4 [24.17] to 244.21 [243.21] %*s, P < 0.05). All paradigms demonstrated changes in subcomponents with cognitive stimulation, and can be ranked based on their relative presumed metabolic demand. The integrity of NVC requires further investigation in patient populations.
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Affiliation(s)
- Lucy Beishon
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
| | | | - Thompson G. Robinson
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- NIHR Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
| | - Victoria J. Haunton
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- NIHR Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
| | - Ronney B. Panerai
- Department of Cardiovascular SciencesUniversity of LeicesterLeicesterUnited Kingdom
- NIHR Leicester Biomedical Research CentreUniversity of LeicesterLeicesterUnited Kingdom
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Wright AD, Smirl JD, Bryk K, van Donkelaar P. A Prospective Transcranial Doppler Ultrasound-Based Evaluation of the Acute and Cumulative Effects of Sport-Related Concussion on Neurovascular Coupling Response Dynamics. J Neurotrauma 2017. [DOI: 10.1089/neu.2017.5020] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Alexander D. Wright
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Jonathan D. Smirl
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Kelsey Bryk
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware
| | - Paul van Donkelaar
- School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
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Smirl JD, Wright AD, Bryk K, van Donkelaar P. Where ’ s Waldo ? The utility of a complicated visual search paradigm for transcranial Doppler-based assessments of neurovascular coupling. J Neurosci Methods 2016; 270:92-101. [DOI: 10.1016/j.jneumeth.2016.06.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 06/07/2016] [Accepted: 06/08/2016] [Indexed: 01/22/2023]
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Phillips AA, Chan FH, Zheng MMZ, Krassioukov AV, Ainslie PN. Neurovascular coupling in humans: Physiology, methodological advances and clinical implications. J Cereb Blood Flow Metab 2016; 36:647-64. [PMID: 26661243 PMCID: PMC4821024 DOI: 10.1177/0271678x15617954] [Citation(s) in RCA: 256] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 10/22/2015] [Accepted: 10/23/2015] [Indexed: 12/16/2022]
Abstract
Neurovascular coupling reflects the close temporal and regional linkage between neural activity and cerebral blood flow. Although providing mechanistic insight, our understanding of neurovascular coupling is largely limited to non-physiologicalex vivopreparations and non-human models using sedatives/anesthetics with confounding cerebrovascular implications. Herein, with particular focus on humans, we review the present mechanistic understanding of neurovascular coupling and highlight current approaches to assess these responses and the application in health and disease. Moreover, we present new guidelines for standardizing the assessment of neurovascular coupling in humans. To improve the reliability of measurement and related interpretation, the utility of new automated software for neurovascular coupling is demonstrated, which provides the capacity for coalescing repetitive trials and time intervals into single contours and extracting numerous metrics (e.g., conductance and pulsatility, critical closing pressure, etc.) according to patterns of interest (e.g., peak/minimum response, time of response, etc.). This versatile software also permits the normalization of neurovascular coupling metrics to dynamic changes in arterial blood gases, potentially influencing the hyperemic response. It is hoped that these guidelines, combined with the newly developed and openly available software, will help to propel the understanding of neurovascular coupling in humans and also lead to improved clinical management of this critical physiological function.
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Affiliation(s)
- Aaron A Phillips
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada International Collaboration on Repair Discoveries (ICORD), UBC, Vancouver, Canada Experimental Medicine Program, Faculty of Medicine, UBC, Vancouver, Canada
| | - Franco Hn Chan
- International Collaboration on Repair Discoveries (ICORD), UBC, Vancouver, Canada
| | - Mei Mu Zi Zheng
- International Collaboration on Repair Discoveries (ICORD), UBC, Vancouver, Canada Experimental Medicine Program, Faculty of Medicine, UBC, Vancouver, Canada
| | - Andrei V Krassioukov
- International Collaboration on Repair Discoveries (ICORD), UBC, Vancouver, Canada Experimental Medicine Program, Faculty of Medicine, UBC, Vancouver, Canada Department of Physical Therapy, UBC, Vancouver, Canada GF Strong Rehabilitation Center, Vancouver, Canada Department of Medicine, Division of Physical Medicine and Rehabilitation, UBC, Vancouver, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
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Potdar AA, Sarkar J, Das NK, Ghosh P, Gratzl M, Fox PL, Saidel GM. Computational modeling and analysis of iron release from macrophages. PLoS Comput Biol 2014; 10:e1003701. [PMID: 24991925 PMCID: PMC4083485 DOI: 10.1371/journal.pcbi.1003701] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 05/16/2014] [Indexed: 01/14/2023] Open
Abstract
A major process of iron homeostasis in whole-body iron metabolism is the release of iron from the macrophages of the reticuloendothelial system. Macrophages recognize and phagocytose senescent or damaged erythrocytes. Then, they process the heme iron, which is returned to the circulation for reutilization by red blood cell precursors during erythropoiesis. The amount of iron released, compared to the amount shunted for storage as ferritin, is greater during iron deficiency. A currently accepted model of iron release assumes a passive-gradient with free diffusion of intracellular labile iron (Fe2+) through ferroportin (FPN), the transporter on the plasma membrane. Outside the cell, a multi-copper ferroxidase, ceruloplasmin (Cp), oxidizes ferrous to ferric ion. Apo-transferrin (Tf), the primary carrier of soluble iron in the plasma, binds ferric ion to form mono-ferric and di-ferric transferrin. According to the passive-gradient model, the removal of ferrous ion from the site of release sustains the gradient that maintains the iron release. Subcellular localization of FPN, however, indicates that the role of FPN may be more complex. By experiments and mathematical modeling, we have investigated the detailed mechanism of iron release from macrophages focusing on the roles of the Cp, FPN and apo-Tf. The passive-gradient model is quantitatively analyzed using a mathematical model for the first time. A comparison of experimental data with model simulations shows that the passive-gradient model cannot explain macrophage iron release. However, a facilitated-transport model associated with FPN can explain the iron release mechanism. According to the facilitated-transport model, intracellular FPN carries labile iron to the macrophage membrane. Extracellular Cp accelerates the oxidation of ferrous ion bound to FPN. Apo-Tf in the extracellular environment binds to the oxidized ferrous ion, completing the release process. Facilitated-transport model can correctly predict cellular iron efflux and is essential for physiologically relevant whole-body model of iron metabolism.
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Affiliation(s)
- Alka A. Potdar
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Joydeep Sarkar
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Nupur K. Das
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Paroma Ghosh
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Miklos Gratzl
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Paul L. Fox
- Department of Cellular and Molecular Medicine, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Gerald M. Saidel
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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