51
|
Ruff IM, Liberman AL, Caprio FZ, Maas MB, Mendelson SJ, Sorond FA, Bergman D, Bernstein RA, Curran Y, Prabhakaran S. A resident boot camp for reducing door-to-needle times at academic medical centers. Neurol Clin Pract 2017; 7:237-245. [PMID: 28680767 DOI: 10.1212/cpj.0000000000000367] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 03/01/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND We sought to determine if a structured educational program for neurology residents can lower door-to-needle (DTN) times at an academic institution. METHODS A neurology resident educational stroke boot camp was developed and implemented in April 2013. Using a prospective database of 170 consecutive acute ischemic stroke (AIS) patients treated with IV tissue plasminogen activator (tPA) in our emergency department (ED), we evaluated the effect of the intervention on DTN times. We compared DTN times and other process measures preintervention and postintervention. p Values < 0.05 were considered significant. RESULTS The proportion of AIS patients treated with tPA within 60 minutes of arrival to our ED tripled from 18.1% preintervention to 61.2% postintervention (p < 0.001) with concomitant reduction in DTN time (median 79 minutes vs 58 minutes, p < 0.001). The resident-delegated task (stroke code to tPA) was reduced (75 minutes vs 44 minutes, p < 0.001), while there was no difference in ED-delegated tasks (door to stroke code [7 minutes vs 6 minutes, p = 0.631], door to CT [18 minutes in both groups, p = 0.547]). There was an increase in stroke mimics treated (6.9% vs 18.4%, p = 0.031), which did not lead to an increase in adverse outcomes. CONCLUSIONS DTN times were reduced after the implementation of a stroke boot camp and were driven primarily by efficient resident stroke code management. Educational programs should be developed for health care providers involved in acute stroke patient care to improve rapid access to IV tPA at academic institutions.
Collapse
Affiliation(s)
- Ilana M Ruff
- Northwestern University (IMR, FZC, MBM, SJM, FAS, DB, RAB, YC, SP), Evanston, IL; and Albert Einstein College of Medicine (ALL), Bronx, NY
| | - Ava L Liberman
- Northwestern University (IMR, FZC, MBM, SJM, FAS, DB, RAB, YC, SP), Evanston, IL; and Albert Einstein College of Medicine (ALL), Bronx, NY
| | - Fan Z Caprio
- Northwestern University (IMR, FZC, MBM, SJM, FAS, DB, RAB, YC, SP), Evanston, IL; and Albert Einstein College of Medicine (ALL), Bronx, NY
| | - Matthew B Maas
- Northwestern University (IMR, FZC, MBM, SJM, FAS, DB, RAB, YC, SP), Evanston, IL; and Albert Einstein College of Medicine (ALL), Bronx, NY
| | - Scott J Mendelson
- Northwestern University (IMR, FZC, MBM, SJM, FAS, DB, RAB, YC, SP), Evanston, IL; and Albert Einstein College of Medicine (ALL), Bronx, NY
| | - Farzaneh A Sorond
- Northwestern University (IMR, FZC, MBM, SJM, FAS, DB, RAB, YC, SP), Evanston, IL; and Albert Einstein College of Medicine (ALL), Bronx, NY
| | - Deborah Bergman
- Northwestern University (IMR, FZC, MBM, SJM, FAS, DB, RAB, YC, SP), Evanston, IL; and Albert Einstein College of Medicine (ALL), Bronx, NY
| | - Richard A Bernstein
- Northwestern University (IMR, FZC, MBM, SJM, FAS, DB, RAB, YC, SP), Evanston, IL; and Albert Einstein College of Medicine (ALL), Bronx, NY
| | - Yvonne Curran
- Northwestern University (IMR, FZC, MBM, SJM, FAS, DB, RAB, YC, SP), Evanston, IL; and Albert Einstein College of Medicine (ALL), Bronx, NY
| | - Shyam Prabhakaran
- Northwestern University (IMR, FZC, MBM, SJM, FAS, DB, RAB, YC, SP), Evanston, IL; and Albert Einstein College of Medicine (ALL), Bronx, NY
| |
Collapse
|
52
|
Malojcic B, Giannakopoulos P, Sorond FA, Azevedo E, Diomedi M, Oblak JP, Carraro N, Boban M, Olah L, Schreiber SJ, Pavlovic A, Garami Z, Bornstein NM, Rosengarten B. Ultrasound and dynamic functional imaging in vascular cognitive impairment and Alzheimer's disease. BMC Med 2017; 15:27. [PMID: 28178960 PMCID: PMC5299782 DOI: 10.1186/s12916-017-0799-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 01/21/2017] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND The vascular contributions to neurodegeneration and neuroinflammation may be assessed by magnetic resonance imaging (MRI) and ultrasonography (US). This review summarises the methodology for these widely available, safe and relatively low cost tools and analyses recent work highlighting their potential utility as biomarkers for differentiating subtypes of cognitive impairment and dementia, tracking disease progression and evaluating response to treatment in various neurocognitive disorders. METHODS At the 9th International Congress on Vascular Dementia (Ljubljana, Slovenia, October 2015) a writing group of experts was formed to review the evidence on the utility of US and arterial spin labelling (ASL) as neurophysiological markers of normal ageing, vascular cognitive impairment (VCI) and Alzheimer's disease (AD). Original articles, systematic literature reviews, guidelines and expert opinions published until September 2016 were critically analysed to summarise existing evidence, indicate gaps in current knowledge and, when appropriate, suggest standards of use for the most widely used US and ASL applications. RESULTS Cerebral hypoperfusion has been linked to cognitive decline either as a risk or an aggravating factor. Hypoperfusion as a consequence of microangiopathy, macroangiopathy or cardiac dysfunction can promote or accelerate neurodegeneration, blood-brain barrier disruption and neuroinflammation. US can evaluate the cerebrovascular tree for pathological structure and functional changes contributing to cerebral hypoperfusion. Microvascular pathology and hypoperfusion at the level of capillaries and small arterioles can also be assessed by ASL, an MRI signal. Despite increasing evidence supporting the utility of these methods in detection of microvascular pathology, cerebral hypoperfusion, neurovascular unit dysfunction and, most importantly, disease progression, incomplete standardisation and missing validated cut-off values limit their use in daily routine. CONCLUSIONS US and ASL are promising tools with excellent temporal resolution, which will have a significant impact on our understanding of the vascular contributions to VCI and AD and may also be relevant for assessing future prevention and therapeutic strategies for these conditions. Our work provides recommendations regarding the use of non-invasive imaging techniques to investigate the functional consequences of vascular burden in dementia.
Collapse
Affiliation(s)
- Branko Malojcic
- Department of Neurology, University Hospital Center Zagreb, Zagreb School of Medicine, Kispaticeva 12, 10000, Zagreb, Croatia.
| | | | - Farzaneh A Sorond
- Department of Neurology, Northwestern University Feinberg School of Medicine Chicago, Chicago, IL, USA
| | - Elsa Azevedo
- Department of Neurology, São João Hospital Center and Faculty of Medicine of University of Porto, Porto, Portugal
| | - Marina Diomedi
- Cerebrovascular Disease Center, Stroke Unit, University of Rome Tor Vergata, Rome, Italy
| | - Janja Pretnar Oblak
- Department of Vascular Neurology and Intensive Therapy, University Medical Center Ljubljana, Ljubljana, Slovenia
| | - Nicola Carraro
- Department of Medical Sciences, Clinical Neurology-Stroke Unit, University Hospital, University of Trieste, Trieste, Italy
| | - Marina Boban
- Department of Neurology, University Hospital Center Zagreb, Zagreb School of Medicine, Kispaticeva 12, 10000, Zagreb, Croatia
| | - Laszlo Olah
- Department of Neurology, University of Debrecen, Debrecen, Hungary
| | - Stephan J Schreiber
- Department of Neurology, Charite - Universitätsmedizin Berlin, Berlin, Germany
| | - Aleksandra Pavlovic
- Neurology Clinic, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Zsolt Garami
- Methodist DeBakey Heart and Vascular Center, Houston, TX, USA
| | - Nantan M Bornstein
- Neurology Department, Tel Aviv Sourasky Medical Centre, Tel Aviv, Israel
| | | |
Collapse
|
53
|
Ruff CT, Ansell JE, Becker RC, Benjamin EJ, Deicicchi DJ, Mark Estes NA, Ezekowitz MD, Fanikos J, Fareed J, Garcia D, Giugliano RP, Goldhaber SZ, Granger C, Healey JS, Hull R, Hylek EM, Libby P, Lopes RD, Mahaffey KW, Mega J, Piazza G, Sasahara AA, Sorond FA, Spyropoulos AC, Walenga JM, Weitz JI. North American Thrombosis Forum, AF Action Initiative Consensus Document. Am J Med 2016; 129:S1-S29. [PMID: 27126598 DOI: 10.1016/j.amjmed.2016.02.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The North American Thrombosis Forum Atrial Fibrillation Action Initiative consensus document is a comprehensive yet practical briefing document focusing on stroke and bleeding risk assessment in patients with atrial fibrillation, as well as recommendations regarding anticoagulation options and management. Despite the breadth of clinical trial data and guideline recommendation updates, many clinicians continue to struggle to synthesize the disparate information available. This problem slows the uptake and utilization of updated risk prediction tools and adoption of new oral anticoagulants. This document serves as a practical and educational reference for the entire medical community involved in the care of patients with atrial fibrillation.
Collapse
Affiliation(s)
- Christian T Ruff
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass.
| | - Jack E Ansell
- Hofstra North Shore/LIJ School of Medicine, Hempstead, NY
| | - Richard C Becker
- University of Cincinnati College of Medicine, University of Cincinnati Medical Center, Ohio
| | - Emelia J Benjamin
- Boston University School of Medicine and Public Health, Boston Medical Center, Boston, Mass
| | | | - N A Mark Estes
- Tufts Medical Center, Tufts University School of Medicine, Boston, Mass
| | - Michael D Ezekowitz
- Lankenau Medical Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pa
| | - John Fanikos
- Massachusetts College of Pharmacy, Brigham and Women's Hospital, Northeastern University School of Pharmacy, Boston, Mass
| | - Jawed Fareed
- Loyola University Medical Center, Loyola University Chicago Stritch School of Medicine, Ill
| | - David Garcia
- University of Washington Medical Center, University of Washington School of Medicine, Seattle, Wash
| | - Robert P Giugliano
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass
| | - Samuel Z Goldhaber
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass
| | - Christopher Granger
- Duke University Medical Center, Duke University School of Medicine, Durham, NC
| | - Jeff S Healey
- Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Russell Hull
- Foothills Medical Center, University of Calgary, Alberta, Canada
| | - Elaine M Hylek
- Boston University School of Medicine and Public Health, Boston Medical Center, Boston, Mass
| | - Peter Libby
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass
| | - Renato D Lopes
- Duke University Medical Center, Duke University School of Medicine, Durham, NC
| | - Kenneth W Mahaffey
- Stanford University Medical Center, Stanford University School of Medicine, Calif
| | - Jessica Mega
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass
| | - Gregory Piazza
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass
| | - Arthur A Sasahara
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass
| | - Farzaneh A Sorond
- Cardiovascular Division, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass
| | | | - Jeanine M Walenga
- Loyola University Medical Center, Loyola University Chicago Stritch School of Medicine, Ill
| | - Jeffrey I Weitz
- Thrombosis and Atherosclerosis Research Institute, McMaster University, Hamilton, Ontario, Canada
| |
Collapse
|
54
|
Santos GA, Petersen N, Zamani AA, Du R, LaRose S, Monk A, Sorond FA, Tan CO. Pathophysiologic differences in cerebral autoregulation after subarachnoid hemorrhage. Neurology 2016; 86:1950-6. [PMID: 27164675 DOI: 10.1212/wnl.0000000000002696] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 02/04/2016] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To understand the physiologic basis of impaired cerebral autoregulation in subarachnoid hemorrhage (SAH) and its relationship to neurologic outcomes. METHODS The cohort included 121 patients with nontraumatic SAH admitted to a neurointensive critical care unit from March 2010 to May 2015. Vasospasm was ascertained from digital subtraction angiography and delayed cerebral ischemia (DCI) was defined as new cerebral infarction on high-resolution CT. Cerebral blood flow and beat-by-beat pressure were recorded daily on days 2-4 after admission. Autoregulatory capacity was quantified from pressure flow relation via projection pursuit regression. The main outcome was early alterations in autoregulatory mechanisms as they relate to vasospasm and DCI. RESULTS Forty-three patients developed only vasospasm, 9 only DCI, and 14 both. Autoregulatory capacity correctly predicted DCI in 86% of training cohort patients, generalizing to 80% of the patients who were not included in the original model. Patients who developed DCI had a distinct autoregulatory profile compared to patients who did not develop secondary complications or those who developed only vasospasm. The rate of decrease in flow was significantly steeper in response to transient reductions in pressure. The rate of increase in flow was markedly lower, suggesting a diminished ability to increase flow despite transient increases in pressure. CONCLUSIONS The extent and nature of impairment in autoregulation accurately predicts neurologic complications on an individual patient level, and suggests potentially differential impairments in underlying physiologic mechanisms. A better understanding of these can lead to targeted interventions to mitigate neurologic morbidity.
Collapse
Affiliation(s)
- Gabriela A Santos
- From the Department of Neurology, Stroke Division (G.A.S., S.L., A.M., F.A.S.), Department of Radiology (A.A.Z.), and Department of Neurosurgery (R.D.), Harvard Medical School, Brigham and Women's Hospital; Cerebrovascular Research Laboratory and Department of Physical Medicine and Rehabilitation (C.O.T.), Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA; and Division of Neurocritical Care and Emergency Neurology (N.P.), Yale School of Medicine and Yale-New Haven Hospital, New Haven, CT
| | - Nils Petersen
- From the Department of Neurology, Stroke Division (G.A.S., S.L., A.M., F.A.S.), Department of Radiology (A.A.Z.), and Department of Neurosurgery (R.D.), Harvard Medical School, Brigham and Women's Hospital; Cerebrovascular Research Laboratory and Department of Physical Medicine and Rehabilitation (C.O.T.), Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA; and Division of Neurocritical Care and Emergency Neurology (N.P.), Yale School of Medicine and Yale-New Haven Hospital, New Haven, CT
| | - Amir A Zamani
- From the Department of Neurology, Stroke Division (G.A.S., S.L., A.M., F.A.S.), Department of Radiology (A.A.Z.), and Department of Neurosurgery (R.D.), Harvard Medical School, Brigham and Women's Hospital; Cerebrovascular Research Laboratory and Department of Physical Medicine and Rehabilitation (C.O.T.), Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA; and Division of Neurocritical Care and Emergency Neurology (N.P.), Yale School of Medicine and Yale-New Haven Hospital, New Haven, CT
| | - Rose Du
- From the Department of Neurology, Stroke Division (G.A.S., S.L., A.M., F.A.S.), Department of Radiology (A.A.Z.), and Department of Neurosurgery (R.D.), Harvard Medical School, Brigham and Women's Hospital; Cerebrovascular Research Laboratory and Department of Physical Medicine and Rehabilitation (C.O.T.), Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA; and Division of Neurocritical Care and Emergency Neurology (N.P.), Yale School of Medicine and Yale-New Haven Hospital, New Haven, CT
| | - Sarah LaRose
- From the Department of Neurology, Stroke Division (G.A.S., S.L., A.M., F.A.S.), Department of Radiology (A.A.Z.), and Department of Neurosurgery (R.D.), Harvard Medical School, Brigham and Women's Hospital; Cerebrovascular Research Laboratory and Department of Physical Medicine and Rehabilitation (C.O.T.), Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA; and Division of Neurocritical Care and Emergency Neurology (N.P.), Yale School of Medicine and Yale-New Haven Hospital, New Haven, CT
| | - Andrew Monk
- From the Department of Neurology, Stroke Division (G.A.S., S.L., A.M., F.A.S.), Department of Radiology (A.A.Z.), and Department of Neurosurgery (R.D.), Harvard Medical School, Brigham and Women's Hospital; Cerebrovascular Research Laboratory and Department of Physical Medicine and Rehabilitation (C.O.T.), Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA; and Division of Neurocritical Care and Emergency Neurology (N.P.), Yale School of Medicine and Yale-New Haven Hospital, New Haven, CT
| | - Farzaneh A Sorond
- From the Department of Neurology, Stroke Division (G.A.S., S.L., A.M., F.A.S.), Department of Radiology (A.A.Z.), and Department of Neurosurgery (R.D.), Harvard Medical School, Brigham and Women's Hospital; Cerebrovascular Research Laboratory and Department of Physical Medicine and Rehabilitation (C.O.T.), Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA; and Division of Neurocritical Care and Emergency Neurology (N.P.), Yale School of Medicine and Yale-New Haven Hospital, New Haven, CT
| | - Can Ozan Tan
- From the Department of Neurology, Stroke Division (G.A.S., S.L., A.M., F.A.S.), Department of Radiology (A.A.Z.), and Department of Neurosurgery (R.D.), Harvard Medical School, Brigham and Women's Hospital; Cerebrovascular Research Laboratory and Department of Physical Medicine and Rehabilitation (C.O.T.), Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA; and Division of Neurocritical Care and Emergency Neurology (N.P.), Yale School of Medicine and Yale-New Haven Hospital, New Haven, CT.
| |
Collapse
|
55
|
Barone FC, Gustafson D, Crystal HA, Moreno H, Adamski MG, Arai K, Baird AE, Balucani C, Brickman AM, Cechetto D, Gorelick P, Biessels GJ, Kiliaan A, Launer L, Schneider J, Sorond FA, Whitmer R, Wright C, Zhang ZG. First translational 'Think Tank' on cerebrovascular disease, cognitive impairment and dementia. J Transl Med 2016; 14:50. [PMID: 26873444 PMCID: PMC4752794 DOI: 10.1186/s12967-016-0806-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 01/22/2016] [Indexed: 01/12/2023] Open
Abstract
As the human population continues to age, an increasing number of people will exhibit significant deficits in cognitive function and dementia. It is now recognized that cerebrovascular, metabolic and neurodegenerative diseases all play major roles in the evolution of cognitive impairment and dementia. Thus with our more recent recognition of these relationships and our need to understand and more positively impact on this world health problem, "The Leo and Anne Albert Charitable Trust" (Gene Pranzo, Trustee with significant support from Susan Brogan, Meeting Planner) provided generous support for this inaugural international workshop that was held from April 13-16, 2015 at the beautiful Ritz Carlton Golf Resort in North Naples, Florida. Researchers from SUNY Downstate Medical Center, Brooklyn, NY organized the event by selecting the present group of translationally inclined preclinical, clinical and population scientists focused on cerebrovascular disease (CVD) risk and its progression to vascular cognitive impairment (VCI) and dementia. Participants at the workshop addressed important issues related to aging, cognition and dementia by: (1) sharing new data, information and perspectives that intersect vascular, metabolic and neurodegenerative diseases, (2) discussing gaps in translating population risk, clinical and preclinical information to the progression of cognitive loss, and (3) debating new approaches and methods to fill these gaps that can translate into future therapeutic interventions. Participants agreed on topics for group discussion prior to the meeting and focused on specific translational goals that included promoting better understanding of dementia mechanisms, the identification of potential therapeutic targets for intervention, and discussed/debated the potential utility of diagnostic/prognostic markers. Below summarizes the new data-presentations, concepts, novel directions and specific discussion topics addressed by this international translational team at our "First Leo and Anne Albert Charitable Trust 'Think Tank' VCI workshop".
Collapse
Affiliation(s)
- Frank C Barone
- Neurology, SUNY Downstate Medical Center, Brooklyn, NY, USA.
- Physiology and Pharmacology, SUNY Downstate Medical Center, Brooklyn, NY, USA.
| | - Deborah Gustafson
- Neurology, SUNY Downstate Medical Center, Brooklyn, NY, USA.
- Section Neuroepidemiology, SUNY Downstate Medical Center, Brooklyn, NY, USA.
| | - Howard A Crystal
- Neurology, SUNY Downstate Medical Center, Brooklyn, NY, USA.
- Pathology, SUNY Downstate Medical Center, Brooklyn, NY, USA.
| | - Herman Moreno
- Neurology, SUNY Downstate Medical Center, Brooklyn, NY, USA.
- Physiology and Pharmacology, SUNY Downstate Medical Center, Brooklyn, NY, USA.
| | - Mateusz G Adamski
- Jagiellonian Centre for Experimental Therapeutics, Jagiellonian University, Krakow, Poland.
| | - Ken Arai
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, CharlesTown, Boston, MA, USA.
| | - Alison E Baird
- Neurology, SUNY Downstate Medical Center, Brooklyn, NY, USA.
- Physiology and Pharmacology, SUNY Downstate Medical Center, Brooklyn, NY, USA.
| | | | - Adam M Brickman
- Taub Institute for Alzheimer's Disease and the Aging Brain, Department of Neurology, Columbia University, New York, NY, USA.
| | - David Cechetto
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada.
| | - Philip Gorelick
- Translational Science and Molecular Medicine, Michigan State University College of Human Medicine, Mercy Health Hauenstein Neurosciences, Grand Rapids, MI, USA.
| | - Geert Jan Biessels
- Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Amanda Kiliaan
- Department of Anatomy, Preclinical Imaging Center, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center Nijmegen, Nijmegen, The Netherlands.
| | - Lenore Launer
- Neuroepidemiology Section, Intramural Research Program, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA.
| | - Julie Schneider
- Pathology (Neuropathology) and Neurological Sciences, Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA.
| | - Farzaneh A Sorond
- Department of Neurology, Stroke Division, Brigham and Women's Hospital, Boston, MA, USA.
| | - Rachel Whitmer
- Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA.
| | - Clinton Wright
- McKnight Brain Institute, Division of Cognitive Disorders, Neurology, Public Health Sciences and Neuroscience, University of Miami, Miami, FL, USA.
| | | |
Collapse
|
56
|
Chow FC, Boscardin WJ, Mills C, Ko N, Carroll C, Price RW, Deeks S, Sorond FA, Hsue PY. Cerebral vasoreactivity is impaired in treated, virally suppressed HIV-infected individuals. AIDS 2016; 30:45-55. [PMID: 26372478 DOI: 10.1097/qad.0000000000000875] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE To compare cerebral vasoreactivity, a measure of cerebrovascular endothelial function, between treated, virally suppressed HIV-infected individuals and HIV-uninfected controls and to evaluate the effect of HIV-specific factors on cerebral vasoreactivity. METHODS Cross-sectional study of 65 antiretroviral therapy-treated, virally suppressed HIV-infected individuals and 28 HIV-uninfected controls. Participants underwent noninvasive assessment of cerebral vasoreactivity using transcranial Doppler ultrasound and inhaled carbon dioxide (CO2). We used mixed effects multivariable linear regression to determine the association of HIV infection and HIV-specific factors with cerebral vasoreactivity. RESULTS Mean age was 57.2 years for HIV-infected participants and 53.5 years for HIV-uninfected controls. Most participants (95%) were men. Twenty-six per cent of HIV-infected participants were nonwhite compared to 32% of controls. Among HIV-infected participants, mean CD4 cell count was 596 cells/μl, and mean duration of viral suppression was 7.8 years. Cerebral vasoreactivity in response to hypercapnia (cerebral VRhyper) was lower in HIV-infected individuals compared to uninfected controls (3.23 versus 3.81%, P = 0.010). After adjusting for demographic and vascular risk factors, HIV infection was independently associated with lower cerebral vasoreactivity (-0.86%, 95% CI -1.30 to -0.42%, P < 0.001). We did not find a statistically significant effect of recent or nadir CD4 cell count on cerebral vasoreactivity. There was a trend toward higher cerebral vasoreactivity for each additional year of viral suppression. CONCLUSION Treated, virally suppressed HIV infection negatively impacted cerebral vasoreactivity even after adjustment for traditional vascular risk factors. These data highlight the potential contribution of cerebrovascular endothelial dysfunction to the elevated risk of stroke observed in HIV-infected individuals.
Collapse
|
57
|
Sorond FA, Cruz-Almeida Y, Clark DJ, Viswanathan A, Scherzer CR, De Jager P, Csiszar A, Laurienti PJ, Hausdorff JM, Chen WG, Ferrucci L, Rosano C, Studenski SA, Black SE, Lipsitz LA. Aging, the Central Nervous System, and Mobility in Older Adults: Neural Mechanisms of Mobility Impairment. J Gerontol A Biol Sci Med Sci 2015; 70:1526-32. [PMID: 26386013 DOI: 10.1093/gerona/glv130] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 07/14/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Mobility is crucial for successful aging and is impaired in many older adults. We know very little about the subtle, subclinical age-related changes in the central nervous system (CNS) that mediate mobility impairment. METHODS A conference series focused on aging, the CNS, and mobility was launched. The second conference addressed major age-associated mechanisms of CNS-mediated mobility impairment. Speakers and conference attendees recommended key areas for future research, identified barriers to progress, and proposed strategies to overcome them. RESULTS Priorities identified for future research include (a) studying interactions among different mechanisms; (b) examining effects of interventions targeting these mechanisms; (c) evaluating the effect of genetic polymorphisms on risks and course of age-related mobility impairment; and (d) examining the effect of age on CNS repair processes, neuroplasticity, and neuronal compensatory mechanisms. Key strategies to promote research include (a) establish standard measures of mobility across species; (b) evaluate the effect of aging in the absence of disease on CNS and mobility; and (c) use advanced computational methods to better evaluate the interactions between CNS and other systems involved in mobility. CONCLUSIONS CNS is a major player in the process, leading to mobility decline with aging. Future research in this area has the potential to prolong independence in older persons. Better interactions among disciplines and shared research paradigms are needed to make progress. Research priorities include the development of innovative approaches to integrate research on aging, cognition, and movement with attention to neurovascular function, neuroplasticity, and neurophysiological reserve.
Collapse
Affiliation(s)
- Farzaneh A Sorond
- Department of Neurology, Stroke Division, Brigham and Women's Hospital, Boston, Massachusetts.
| | - Yenisel Cruz-Almeida
- Institute on Aging, Department of Aging and Geriatric Research, College of Medicine, University of Florida, Gainesville
| | - David J Clark
- Brain Rehabilitation Research Center, North Florida/South Georgia Veterans Health System, Department of Aging and Geriatric Research, University of Florida, Gainesville
| | - Anand Viswanathan
- Department of Neurology, Stroke Division, Massachusetts General Hospital, Harvard Medical School, Boston
| | - Clemens R Scherzer
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Philip De Jager
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Anna Csiszar
- Reynolds Oklahoma Center on Aging, Department of Geriatric Medicine, University of Oklahoma Health Sciences Center
| | - Paul J Laurienti
- Department of Radiology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Jeffery M Hausdorff
- Department of Medicine, Tel-Aviv University, Tel-Aviv Sourasky Medical Center, Israel
| | - Wen G Chen
- Sensory and Motor Disorders of Aging and
| | - Luiggi Ferrucci
- Longitudinal Studies Section, National Institute on Aging, Bethesda, Maryland
| | - Caterina Rosano
- Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pennsylvania
| | - Stephanie A Studenski
- Department of Medicine, Division of Geriatric Medicine, Pittsburgh Healthcare System, Pennsylvania
| | - Sandra E Black
- Department of Neurology, University of Toronto, Sunnybrook Research Institute, Canada
| | - Lewis A Lipsitz
- Institute for Aging Research, Research, Hebrew Senior Life, Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
58
|
Pan WC, Eliot MN, Koutrakis P, Coull BA, Sorond FA, Wellenius GA. Ambient Temperature and Cerebrovascular Hemodynamics in the Elderly. PLoS One 2015; 10:e0134034. [PMID: 26258469 PMCID: PMC4721538 DOI: 10.1371/journal.pone.0134034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Accepted: 07/05/2015] [Indexed: 11/19/2022] Open
Abstract
Background and Purpose Some prior studies have linked ambient temperature with risk of cerebrovascular events. If causal, the pathophysiologic mechanisms underlying this putative association remain unknown. Temperature-related changes in cerebral vascular function may play a role, but this hypothesis has not been previously evaluated. Methods We evaluated the association between ambient temperature and cerebral vascular function among 432 participants ≥65 years old from the MOBILIZE Boston Study with data on cerebrovascular blood flow, cerebrovascular resistance, and cerebrovascular reactivity in the middle cerebral artery. We used linear regression models to assess the association of mean ambient temperature in the previous 1 to 28 days with cerebrovascular hemodynamics adjusting for potential confounding factors. Results A 10°C increase in the 21-day moving average of ambient temperature was associated with a 10.1% (95% confidence interval [CI], 2.2%, 17.3%) lower blood flow velocity, a 9.0% (95% CI, 0.7%, 18.0%) higher cerebrovascular resistance, and a 15.3% (95%CI, 2.7%, 26.4%) lower cerebral vasoreactivity. Further adjustment for ozone and fine particulate matter (PM2.5) did not materially alter the results. However, we found statistically significant interactions between ambient temperature and PM2.5 such that the association between temperature and blood flow velocity was attenuated at higher levels of PM2.5. Conclusions In this elderly population, we found that ambient temperature was negatively associated with cerebral blood flow velocity and cerebrovascular vasoreactivity and positively associated with cerebrovascular resistance. Changes in vascular function may partly underlie the observed associations between ambient temperature and risk of cerebrovascular events.
Collapse
Affiliation(s)
- Wen-Chi Pan
- Department of Epidemiology, Brown University School of Public Health, Providence, RI, United States of America
| | - Melissa N. Eliot
- Department of Epidemiology, Brown University School of Public Health, Providence, RI, United States of America
| | - Petros Koutrakis
- Department of Environmental Health, Harvard School of Public Health, Boston, MA, United States of America
| | - Brent A. Coull
- Department of Biostatistics, Harvard School of Public Health, Boston, MA, United States of America
| | - Farzaneh A. Sorond
- Department of Neurology, Brigham and Women’s Hospital and Institute for Aging Research, Hebrew SeniorLife, Boston, MA, United States of America
| | - Gregory A. Wellenius
- Department of Epidemiology, Brown University School of Public Health, Providence, RI, United States of America
- * E-mail:
| |
Collapse
|
59
|
Sorond FA, Tan CO, LaRose S, Monk AD, Fichorova R, Ryan S, Lipsitz LA. Deferoxamine, Cerebrovascular Hemodynamics, and Vascular Aging: Potential Role for Hypoxia-Inducible Transcription Factor-1-Regulated Pathways. Stroke 2015; 46:2576-83. [PMID: 26304864 DOI: 10.1161/strokeaha.115.009906] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 07/02/2015] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND PURPOSE Iron chelation therapy is emerging as a novel neuroprotective strategy. The mechanisms of neuroprotection are diverse and include both neuronal and vascular pathways. We sought to examine the effect of iron chelation on cerebrovascular function in healthy aging and to explore whether hypoxia-inducible transcription factor-1 activation may be temporally correlated with vascular changes. METHODS We assessed cerebrovascular function (autoregulation, vasoreactivity, and neurovascular coupling) and serum concentrations of vascular endothelial growth factor and erythropoietin, as representative measures of hypoxia-inducible transcription factor-1 activation, during 6 hours of deferoxamine infusion in 24 young and 24 older healthy volunteers in a randomized, blinded, placebo-controlled cross-over study design. Cerebrovascular function was assessed using the transcranial Doppler ultrasound. Vascular endothelial growth factor and erythropoietin serum protein assays were conducted using the Meso Scale Discovery platform. RESULTS Deferoxamine elicited a strong age- and time-dependent increase in the plasma concentrations of erythropoietin and vascular endothelial growth factor, which persisted ≤3 hours post infusion (age effect P=0.04; treatment×time P<0.01). Deferoxamine infusion also resulted in a significant time- and age-dependent improvement in cerebral vasoreactivity (treatment×time P<0.01; age P<0.01) and cerebral autoregulation (gain: age×time×treatment P=0.04). CONCLUSIONS Deferoxamine infusion improved cerebrovascular function, particularly in older individuals. The temporal association between improved cerebrovascular function and increased serum vascular endothelial growth factor and erythropoietin concentrations is supportive of shared hypoxia-inducible transcription factor-1-regulated pathways. Therefore, pharmacological activation of hypoxia-inducible transcription factor-1 to enhance cerebrovascular function may be a promising neuroprotective strategy in acute and chronic ischemic syndromes, especially in elderly patients. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT013655104.
Collapse
Affiliation(s)
- Farzaneh A Sorond
- From the Stroke Division, Department of Neurology (F.A.S., S.L.R., A.D.M.) and Laboratory of Genital Tract Biology, Department of Obstetrics, Gynecology and Reproductive Biology (R.F., S.R.), Brigham and Women's Hospital, Boston, MA; Cardiovascular Research Laboratory, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA (C.O.T.); Department of Medicine, Hebrew SeniorLife Institute for Aging Research, Boston, MA (L.A.L.); Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, MA (L.A.L.); and Department of Neurology, Physical Medicine and Rehabilitation, Obstetrics and Gynecology, and Medicine, Harvard Medical School, Boston, MA (F.A.S., C.O.T., R.F., L.A.L.).
| | - Can Ozan Tan
- From the Stroke Division, Department of Neurology (F.A.S., S.L.R., A.D.M.) and Laboratory of Genital Tract Biology, Department of Obstetrics, Gynecology and Reproductive Biology (R.F., S.R.), Brigham and Women's Hospital, Boston, MA; Cardiovascular Research Laboratory, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA (C.O.T.); Department of Medicine, Hebrew SeniorLife Institute for Aging Research, Boston, MA (L.A.L.); Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, MA (L.A.L.); and Department of Neurology, Physical Medicine and Rehabilitation, Obstetrics and Gynecology, and Medicine, Harvard Medical School, Boston, MA (F.A.S., C.O.T., R.F., L.A.L.)
| | - Sarah LaRose
- From the Stroke Division, Department of Neurology (F.A.S., S.L.R., A.D.M.) and Laboratory of Genital Tract Biology, Department of Obstetrics, Gynecology and Reproductive Biology (R.F., S.R.), Brigham and Women's Hospital, Boston, MA; Cardiovascular Research Laboratory, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA (C.O.T.); Department of Medicine, Hebrew SeniorLife Institute for Aging Research, Boston, MA (L.A.L.); Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, MA (L.A.L.); and Department of Neurology, Physical Medicine and Rehabilitation, Obstetrics and Gynecology, and Medicine, Harvard Medical School, Boston, MA (F.A.S., C.O.T., R.F., L.A.L.)
| | - Andrew D Monk
- From the Stroke Division, Department of Neurology (F.A.S., S.L.R., A.D.M.) and Laboratory of Genital Tract Biology, Department of Obstetrics, Gynecology and Reproductive Biology (R.F., S.R.), Brigham and Women's Hospital, Boston, MA; Cardiovascular Research Laboratory, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA (C.O.T.); Department of Medicine, Hebrew SeniorLife Institute for Aging Research, Boston, MA (L.A.L.); Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, MA (L.A.L.); and Department of Neurology, Physical Medicine and Rehabilitation, Obstetrics and Gynecology, and Medicine, Harvard Medical School, Boston, MA (F.A.S., C.O.T., R.F., L.A.L.)
| | - Raina Fichorova
- From the Stroke Division, Department of Neurology (F.A.S., S.L.R., A.D.M.) and Laboratory of Genital Tract Biology, Department of Obstetrics, Gynecology and Reproductive Biology (R.F., S.R.), Brigham and Women's Hospital, Boston, MA; Cardiovascular Research Laboratory, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA (C.O.T.); Department of Medicine, Hebrew SeniorLife Institute for Aging Research, Boston, MA (L.A.L.); Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, MA (L.A.L.); and Department of Neurology, Physical Medicine and Rehabilitation, Obstetrics and Gynecology, and Medicine, Harvard Medical School, Boston, MA (F.A.S., C.O.T., R.F., L.A.L.)
| | - Stanthia Ryan
- From the Stroke Division, Department of Neurology (F.A.S., S.L.R., A.D.M.) and Laboratory of Genital Tract Biology, Department of Obstetrics, Gynecology and Reproductive Biology (R.F., S.R.), Brigham and Women's Hospital, Boston, MA; Cardiovascular Research Laboratory, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA (C.O.T.); Department of Medicine, Hebrew SeniorLife Institute for Aging Research, Boston, MA (L.A.L.); Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, MA (L.A.L.); and Department of Neurology, Physical Medicine and Rehabilitation, Obstetrics and Gynecology, and Medicine, Harvard Medical School, Boston, MA (F.A.S., C.O.T., R.F., L.A.L.)
| | - Lewis A Lipsitz
- From the Stroke Division, Department of Neurology (F.A.S., S.L.R., A.D.M.) and Laboratory of Genital Tract Biology, Department of Obstetrics, Gynecology and Reproductive Biology (R.F., S.R.), Brigham and Women's Hospital, Boston, MA; Cardiovascular Research Laboratory, Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA (C.O.T.); Department of Medicine, Hebrew SeniorLife Institute for Aging Research, Boston, MA (L.A.L.); Division of Gerontology, Beth Israel Deaconess Medical Center, Boston, MA (L.A.L.); and Department of Neurology, Physical Medicine and Rehabilitation, Obstetrics and Gynecology, and Medicine, Harvard Medical School, Boston, MA (F.A.S., C.O.T., R.F., L.A.L.)
| |
Collapse
|
60
|
Tchalla AE, Wellenius GA, Travison TG, Gagnon M, Iloputaife I, Dantoine T, Sorond FA, Lipsitz LA. Circulating vascular cell adhesion molecule-1 is associated with cerebral blood flow dysregulation, mobility impairment, and falls in older adults. Hypertension 2015; 66:340-6. [PMID: 26056332 DOI: 10.1161/hypertensionaha.115.05180] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/12/2015] [Indexed: 11/16/2022]
Abstract
Soluble vascular cell adhesion molecule-1 (sVCAM-1) is associated with hypertension, vascular inflammation, and systemic endothelial dysfunction. We evaluated whether elevated plasma sVCAM-1 is associated with impaired cerebrovascular function and mobility impairments in elderly people. We studied the cross-sectional relationships between plasma sVCAM-1 level, gait speed, and cerebrovascular hemodynamics, and its longitudinal relationship with falls in 680 community-dwelling participants aged ≥65 years in the Maintenance of Balance, Independent Living, Intellect, and Zest in the Elderly (MOBILIZE) Boston Study. Falls were recorded prospectively for 1 year on daily calendars. sVCAM-1 was measured by ELISA assay and beat-to-beat blood flow velocity in the middle cerebral artery during rest and in response to changes in end-tidal CO2 was measured by transcranial Doppler ultrasound. sVCAM-1 concentration was 1094±340 ng/mL in normotensives, 1195±438 ng/mL in controlled hypertensives, and 1250±445 ng/mL in uncontrolled hypertensives (P=0.008). The mean resting blood flow velocity and cerebral vasomotor range were, respectively, 41.0±10.3 cm/s and 1.3±0.4 cm/s per millimeter of mercury. Elevated sVCAM-1 levels indicative of endothelial dysfunction were associated with reduced resting blood flow velocity (P=0.017) and cerebral vasomotor range (P=0.0048). Elevated sVCAM-1 levels were associated with slower gait speed (<0.8 m/s; odds ratio, 3.01; 95% confidence interval, 1.56-5.83; P=0.0011) and an increased odds of injurious falls (odds ratio, 2.4; 95% confidence interval, 1.4-4.2; P=0.0028). An elevated sVCAM-1 level may be a marker of cerebral blood flow dysregulation because of endothelial damage from hypertension. It may also signal the presence of cerebral microvascular disease and its clinical consequences, including slow gait speed and falls.
Collapse
Affiliation(s)
- Achille E Tchalla
- From the Institute for Aging Research, Hebrew SeniorLife, Boston, MA (A.E.T., T.G.T., M.G., L.A.L); Beth Israel Deaconess Medical Center, Boston, MA (A.E.T., T.G.T., L.A.L.); Harvard Medical School, Boston, MA (A.E.T., T.G.T., L.A.L.); Limoges University, Limoges, France (A.E.T., T.D.); IFR 145 GEIST; EA 6310 HAVAE (Disability, Activity, Aging, Autonomy and Environment), Geriatric Medicine Department, CHU Limoges, Limoges, France (A.E.T., T.D.); Brown University School of Public Health, Providence, MA (G.A.W.); and Stroke Division, Department of Neurology, Brigham and Women's Hospital, Boston, MA (F.A.S.)
| | - Gregory A Wellenius
- From the Institute for Aging Research, Hebrew SeniorLife, Boston, MA (A.E.T., T.G.T., M.G., L.A.L); Beth Israel Deaconess Medical Center, Boston, MA (A.E.T., T.G.T., L.A.L.); Harvard Medical School, Boston, MA (A.E.T., T.G.T., L.A.L.); Limoges University, Limoges, France (A.E.T., T.D.); IFR 145 GEIST; EA 6310 HAVAE (Disability, Activity, Aging, Autonomy and Environment), Geriatric Medicine Department, CHU Limoges, Limoges, France (A.E.T., T.D.); Brown University School of Public Health, Providence, MA (G.A.W.); and Stroke Division, Department of Neurology, Brigham and Women's Hospital, Boston, MA (F.A.S.)
| | - Thomas G Travison
- From the Institute for Aging Research, Hebrew SeniorLife, Boston, MA (A.E.T., T.G.T., M.G., L.A.L); Beth Israel Deaconess Medical Center, Boston, MA (A.E.T., T.G.T., L.A.L.); Harvard Medical School, Boston, MA (A.E.T., T.G.T., L.A.L.); Limoges University, Limoges, France (A.E.T., T.D.); IFR 145 GEIST; EA 6310 HAVAE (Disability, Activity, Aging, Autonomy and Environment), Geriatric Medicine Department, CHU Limoges, Limoges, France (A.E.T., T.D.); Brown University School of Public Health, Providence, MA (G.A.W.); and Stroke Division, Department of Neurology, Brigham and Women's Hospital, Boston, MA (F.A.S.)
| | - Margaret Gagnon
- From the Institute for Aging Research, Hebrew SeniorLife, Boston, MA (A.E.T., T.G.T., M.G., L.A.L); Beth Israel Deaconess Medical Center, Boston, MA (A.E.T., T.G.T., L.A.L.); Harvard Medical School, Boston, MA (A.E.T., T.G.T., L.A.L.); Limoges University, Limoges, France (A.E.T., T.D.); IFR 145 GEIST; EA 6310 HAVAE (Disability, Activity, Aging, Autonomy and Environment), Geriatric Medicine Department, CHU Limoges, Limoges, France (A.E.T., T.D.); Brown University School of Public Health, Providence, MA (G.A.W.); and Stroke Division, Department of Neurology, Brigham and Women's Hospital, Boston, MA (F.A.S.)
| | - Ikechukwu Iloputaife
- From the Institute for Aging Research, Hebrew SeniorLife, Boston, MA (A.E.T., T.G.T., M.G., L.A.L); Beth Israel Deaconess Medical Center, Boston, MA (A.E.T., T.G.T., L.A.L.); Harvard Medical School, Boston, MA (A.E.T., T.G.T., L.A.L.); Limoges University, Limoges, France (A.E.T., T.D.); IFR 145 GEIST; EA 6310 HAVAE (Disability, Activity, Aging, Autonomy and Environment), Geriatric Medicine Department, CHU Limoges, Limoges, France (A.E.T., T.D.); Brown University School of Public Health, Providence, MA (G.A.W.); and Stroke Division, Department of Neurology, Brigham and Women's Hospital, Boston, MA (F.A.S.)
| | - Thierry Dantoine
- From the Institute for Aging Research, Hebrew SeniorLife, Boston, MA (A.E.T., T.G.T., M.G., L.A.L); Beth Israel Deaconess Medical Center, Boston, MA (A.E.T., T.G.T., L.A.L.); Harvard Medical School, Boston, MA (A.E.T., T.G.T., L.A.L.); Limoges University, Limoges, France (A.E.T., T.D.); IFR 145 GEIST; EA 6310 HAVAE (Disability, Activity, Aging, Autonomy and Environment), Geriatric Medicine Department, CHU Limoges, Limoges, France (A.E.T., T.D.); Brown University School of Public Health, Providence, MA (G.A.W.); and Stroke Division, Department of Neurology, Brigham and Women's Hospital, Boston, MA (F.A.S.)
| | - Farzaneh A Sorond
- From the Institute for Aging Research, Hebrew SeniorLife, Boston, MA (A.E.T., T.G.T., M.G., L.A.L); Beth Israel Deaconess Medical Center, Boston, MA (A.E.T., T.G.T., L.A.L.); Harvard Medical School, Boston, MA (A.E.T., T.G.T., L.A.L.); Limoges University, Limoges, France (A.E.T., T.D.); IFR 145 GEIST; EA 6310 HAVAE (Disability, Activity, Aging, Autonomy and Environment), Geriatric Medicine Department, CHU Limoges, Limoges, France (A.E.T., T.D.); Brown University School of Public Health, Providence, MA (G.A.W.); and Stroke Division, Department of Neurology, Brigham and Women's Hospital, Boston, MA (F.A.S.)
| | - Lewis A Lipsitz
- From the Institute for Aging Research, Hebrew SeniorLife, Boston, MA (A.E.T., T.G.T., M.G., L.A.L); Beth Israel Deaconess Medical Center, Boston, MA (A.E.T., T.G.T., L.A.L.); Harvard Medical School, Boston, MA (A.E.T., T.G.T., L.A.L.); Limoges University, Limoges, France (A.E.T., T.D.); IFR 145 GEIST; EA 6310 HAVAE (Disability, Activity, Aging, Autonomy and Environment), Geriatric Medicine Department, CHU Limoges, Limoges, France (A.E.T., T.D.); Brown University School of Public Health, Providence, MA (G.A.W.); and Stroke Division, Department of Neurology, Brigham and Women's Hospital, Boston, MA (F.A.S.).
| |
Collapse
|
61
|
Tchalla AE, Wellenius GA, Sorond FA, Travison TG, Dantoine T, Lipsitz LA. Elevated circulating vascular cell Adhesion Molecule-1 (sVCAM-1) is associated with concurrent depressive symptoms and cerebral white matter Hyperintensities in older adults. BMC Geriatr 2015; 15:62. [PMID: 26040277 PMCID: PMC4453284 DOI: 10.1186/s12877-015-0063-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 05/26/2015] [Indexed: 11/10/2022] Open
Abstract
Background Circulating vascular adhesion molecule-1 (sVCAM-1) is a presumed marker of endothelial activation and dysfunction, but little is known about its association with mood. We hypothesized that elevated plasma concentrations of sVCAM-1 may be a marker of depressive symptoms due to cerebral vascular disease. Methods We studied 680 community-dwelling participants in the MOBILIZE Boston Study, aged 65 years and older. sICAM-1 and sVCAM-1 were measured by ELISA assay and depressive symptoms were assessed during home interviews using the Revised Center for Epidemiological Studies Depression Scale (CESD-R). Cerebral White Matter Hyperintensities (WMHs) were quantified by MRI in a subgroup of 25 participants. Results One hundred seventy nine (27 %) subjects had a CESD-R Score ≥ 16, indicative of depressive symptoms. The mean sVCAM-1 concentration (±SD) was 1176 ± 417 ng/mL in a group with CESD-R Scores <16 and 1239 ± 451 ng/mL in those with CESD-R Scores ≥16 (p = 0.036). CESD-R Score was positively associated with sVCAM-1 (r = 0.11, p = 0.004). The highest quintile of sVCAM-1, which is indicative of endothelial dysfunction, was significantly associated with depressive symptoms compared to the lowest quintile (OR = 1.97 (1.14-3.57) p = 0.015). In a subset of subjects, sVCAM-1 concentration was positively correlated with cerebral WMHs volume (p = 0.018). Conclusions The association between high levels of sVCAM-1 and depressive symptoms may be due to endothelial dysfunction from cerebral microvascular damage. Future longitudinal studies are needed to determine whether sVCAM-1 can serve as a biomarker for cerebrovascular causes of depression.
Collapse
Affiliation(s)
- Achille E Tchalla
- Institute for Aging Research, Hebrew SeniorLife, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA. .,Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA. .,Harvard Medical School, Boston, Massachusetts, USA. .,Geriatric Medicine Department, IFR 145 GEIST; EA 6310 HAVAE (Disability, Activity, Aging, Autonomy and Environment), Limoges University, CHU Limoges, Limoges, F-87025, France.
| | | | - Farzaneh A Sorond
- Department of Neurology, Stroke Division, Brigham and Women's Hospital, 45 Francis St, Boston, MA, 02115, USA.
| | - Thomas G Travison
- Institute for Aging Research, Hebrew SeniorLife, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
| | - Thierry Dantoine
- Geriatric Medicine Department, IFR 145 GEIST; EA 6310 HAVAE (Disability, Activity, Aging, Autonomy and Environment), Limoges University, CHU Limoges, Limoges, F-87025, France.
| | - Lewis A Lipsitz
- Institute for Aging Research, Hebrew SeniorLife, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA. .,Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA. .,Harvard Medical School, Boston, Massachusetts, USA.
| |
Collapse
|
62
|
Chou SHY, Latorre JGS, Alpargu G, Ogilvy CS, Sorond FA, Rordorf G. Outcomes after Early Anticonvulsant Discontinuation in Aneurysmal Subarachnoid Hemorrhage. J Vasc Med Surg 2015; 3. [PMID: 34568512 PMCID: PMC8460122 DOI: 10.4172/2329-6925.1000173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Background: Empiric use of anticonvulsant (AED) for seizure prophylaxis in aneurysmal subarachnoid hemorrhage (SAH) remains controversial and may be associated with worse SAH outcome. We determined the safety and feasibility of early discontinuation of empiric AED in a select cohort of SAH patients. Methods: In a cohort of 166 consecutive SAH patients, a subset underwent early AED discontinuation if they were awake and following commands after aneurysm treatment. We examined the effect of AED discontinuation on seizure incidence, mortality and functional outcome at discharge using logistic regression and validated results using 70%-30% data partition. Results: Seventy-three subjects underwent AED discontinuation. Patient groups had similar gender, age, Fisher grade, incidence of craniotomy, vasospasm, ischemic infarct, intraventricular and intraparenchymal hemorrhages. Hunt-Hess (HH) grade were lower in AED-discontinuation group. Clinical or electrographic seizure occurred in 1/93 (1%) patients on AED and 0/73 patient in AED-discontinuation group. Crude mortality was 24% in patients on AED and 2.7% off AED. After adjusting for age, HH grade, vasospasm, ischemic infarct, intracerebral, and intraventricular hemorrhage, AED discontinuation remains independently associated with lower mortality and higher odds of discharge to home (p=0.0002). AED use is not associated with angiographic vasospasm on exploratory analysis. Conclusion: AED discontinuation in SAH patients who are awake and following commands post aneurysm treatment is safe, feasible, and associated with better outcome at hospital discharge. A larger, prospective study is necessary to determine if empiric AED use in SAH leads to poorer functional status.
Collapse
Affiliation(s)
- Sherry Hsiang-Yi Chou
- Departments of Critical Care Medicine, Neurology, and Neurosurgery, University of Pittsburgh School of Medicine, USA
| | | | - Gulhan Alpargu
- Department of Statistics, California State University Fullerton, USA
| | - Christopher S Ogilvy
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, USA
| | - Farzaneh A Sorond
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, USA
| | - Guy Rordorf
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, USA
| |
Collapse
|
63
|
Chou SH, Feske SK, Suh S, Lieu K, Du R, Henderson GV, Sorond FA, Lo EH, Ning M. Abstract W MP28: Early Elevation of Plasma Soluble Fms-Like Tyrosine Kinase-1 is Associated With Poor Functional Outcome After Subarachnoid Hemorrhage. Stroke 2014. [DOI: 10.1161/str.45.suppl_1.wmp28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background:
Vasospasm (VSP) and brain injury following subarachnoid hemorrhage (SAH) are associated with tissue hypoxia and vascular endothelial growth factor (VEGF) release. Soluble Fms-like tyrosine kinase-1 (sFlt-1), a truncated soluble form of VEGF receptor-1, is an endogenous VEGF inhibitor released in response to hypoxia and nitric oxide deficiency. SFlt-1 is anti-angiogenic and mediates endothelial dysfunction. We hypothesize sFlt-1 elevation may be associated with VSP and poor SAH outcome.
Methods:
We prospectively enrolled consecutive SAH subjects, banked serial blood samples, and evaluated their modified Rankin scores (mRS) at 3 month intervals. Poor functional outcome was defined as mRS>2. Angiographic VSP was defined as >50% reduction in caliber of any vessel on post-SAH day 7 cerebral angiogram. In 63 SAH subjects, we compared plasma sFlt-1 by ELISA on post-SAH days 3 and 5 by VSP and outcome status using Wilcoxon rank sum or Student’s t-test depending on data distribution. Bonferroni correction was used for multiple comparisons. Logistic regression was used to adjust for confounders. Associations were measured using Pearson’s or Spearman’s correlation depending on data distribution.
Results:
Twenty-seven subjects (43%) had poor 3-month outcome and 31 (49%) developed VSP. Elevated sFlt-1 level on post-SAH day 3 was associated with poor 3-month outcome (p=0.02) while post-SAH day 5 sFlt-1 level showed no association. SFlt-1 levels were not associated with Hunt and Hess (HH) or Fisher grades or with VSP. SFlt-1 was inversely correlated to VEGF (p=0.04, r=0.26). Post-SAH day 3 sFlt-1 level was independently associated with poor SAH outcome after adjustment for HH grade, age, and VEGF level (p=0.03). VEGF was not associated with VSP or SAH outcome.
Conclusion:
Early elevation of plasma sFlt-1 on post-SAH day 3 is independently associated with poor 3-month SAH outcome after adjustment for clinical predictors of SAH outcome and for VEGF. Inverse correlation suggests possible negative feedback control between sFlt-1 and VEGF in SAH. Future studies are necessary to determine the source of sFlt-1 in SAH and its role in SAH-associated brain injury. Replication in a larger cohort is necessary to validate sFlt-1 as a potential biomarker for SAH outcome.
Collapse
Affiliation(s)
- Sherry H Chou
- Dept of Neurology, Brigham and Women's Hosp, Harvard Med Sch, Boston, MA
| | - Steven K Feske
- Dept of Neurology, Brigham and Women's Hosp, Harvard Med Sch, Boston, MA
| | - Sarah Suh
- Dept of Neurology, Brigham and Women's Hosp, Boston, MA
| | - Kristina Lieu
- Dept of Neurology, Brigham and Women's Hosp, Boston, MA
| | - Rose Du
- Dept of Neurosurgery, Brigham and Women's Hosp, Harvard Med Sch, Boston, MA
| | - Galen V Henderson
- Dept of Neurology, Brigham and Women's Hosp, Harvard Med Sch, Boston, MA
| | - Farzaneh A Sorond
- Dept of Neurology, Brigham and Women's Hosp, Harvard Med Sch, Boston, MA
| | - Eng H Lo
- Dept of Radiology and Neurology, Massachusetts General Hosp; Harvard Med Sch, Boston, MA
| | - MingMing Ning
- Dept of Neurology, Massachusetts General Hosp; Harvard Med Sch, Boston, MA
| |
Collapse
|
64
|
Chou SH, Icli B, Cahill M, Du R, Suh S, Henderson GV, Sorond FA, Feske SK, Lo EH, Ning M, Feinberg MW. Abstract W MP29: CSF MicroRNA-181b is Associated With Poor 6-Month Outcome Following Subarachnoid Hemorrhage. Stroke 2014. [DOI: 10.1161/str.45.suppl_1.wmp29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background:
Early brain injury and vasospasm (VSP) in subarachnoid hemorrhage (SAH) are associated with inflammation and release of TNFα, which correlates with poor SAH clinical outcome. TNFα regulates the expression of microRNA (miR) 181b, which mediates NF-κB signaling and is known to exacerbate ischemic stroke in animal models. MiRs have higher stability in biological fluids than peptides and may be candidate clinical biomarkers. We hypothesize that miR-181b is present in SAH CSF and may be associated with SAH outcome.
Methods:
We prospectively enrolled consecutive SAH subjects, banked serial CSF samples, and evaluated their modified Rankin scores (mRS) via telephone follow-up every 3 months. Poor functional outcome was defined as mRS>2. Angiographic VSP was defined as >50% reduction in caliber of any vessel on post-SAH day 7 cerebral angiogram. In 54 SAH subjects, we compared CSF miR-181b and 26a (as control) by quantitative PCR on post-SAH day 3 with respect to VSP and outcome using Student’s t-test after log-transformation of data with non-normal distribution. Associations were measured using Pearson’s or Spearman’s correlation depending on data distribution.
Results:
Twenty-seven subjects (50%) developed VSP and 21 (39%) had poor 6-month outcome. MiRs-181b and 26a were consistently measurable in SAH CSF, and miR levels were not associated with Hunt and Hess or Fisher grades. Elevation of CSF miR-181b was associated with poor 6-month outcome in SAH (p=0.04). CSF miR-181b inversely correlated with blood TNFα (r=0.74, p=0.0001). CSF miR-181b was not associated with VSP. CSF miR-26a was not associated with VSP or with clinical outcome in SAH.
Conclusion:
MiR-181b is present in human CSF after SAH and early elevation of CSF miR-181b is associated with poor 6-month outcome but not with VSP after SAH. Lack of association between control miR-26a and outcome suggests that association between miR-181b and SAH outcome is not due to a non-specific miR surge in more severe cases. Inverse correlation between blood TNFα and CSF miR-181b suggests TNFα may mediate miR-181b release into CSF. Future mechanistic studies on the role of miR-181b in SAH-related brain injury and validation studies in larger cohorts are necessary to understand the role of miR-181b as a SAH biomarker.
Collapse
Affiliation(s)
- Sherry H Chou
- Dept of Neurology, Brigham and Women's Hosp; Harvard Med Sch, Boston, MA
| | - Basak Icli
- Cardiovascular Div, Brigham and Women's Hosp; Harvard Med Sch, Boston, MA
| | - Meghan Cahill
- Cardiovascular Div, Brigham and Women's Hosp, Boston, MA
| | - Rose Du
- Dept of Neurosurgery, Brigham and Women's Hosp; Harvard Med Sch, Boston, MA
| | - Sarah Suh
- Dept of Neurology, Brigham and Women's Hosp, Boston, MA
| | - Galen V Henderson
- Dept of Neurology, Brigham and Women's Hosp; Harvard Med Sch, Boston, MA
| | - Farzaneh A Sorond
- Dept of Neurology, Brigham and Women's Hosp; Harvard Med Sch, Boston, MA
| | - Steven K Feske
- Dept of Neurology, Brigham and Women's Hosp; Harvard Med Sch, Boston, MA
| | - Eng H Lo
- Dept of Radiology and Neurology, Massachusetts General Hosp; Harvard Med Sch, Boston, MA
| | - MingMing Ning
- Dept of Neurology, Massachusetts General Hosp; Harvard Med Sch, Boston, MA
| | - Mark W Feinberg
- Cardiovascular Div, Brigham and Women's Hosp; Harvard Med Sch, Boston, MA
| |
Collapse
|
65
|
Otite F, Mink S, Tan CO, Puri A, Zamani AA, Mehregan A, Chou S, Orzell S, Purkayastha S, Du R, Sorond FA. Impaired cerebral autoregulation is associated with vasospasm and delayed cerebral ischemia in subarachnoid hemorrhage. Stroke 2014; 45:677-82. [PMID: 24425120 DOI: 10.1161/strokeaha.113.002630] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Cerebral autoregulation may be impaired in the early days after subarachnoid hemorrhage (SAH). The purpose of this study was to examine the relationship between cerebral autoregulation and angiographic vasospasm (aVSP) and radiographic delayed cerebral ischemia (DCI) in patients with SAH. METHODS Sixty-eight patients (54±13 years) with a diagnosis of nontraumatic SAH were studied. Dynamic cerebral autoregulation was assessed using transfer function analysis (phase and gain) of the spontaneous blood pressure and blood flow velocity oscillations on days 2 to 4 post-SAH. aVSP was diagnosed using a 4-vessel conventional angiogram. DCI was diagnosed from CT. Decision tree models were used to identify optimal cut-off points for clinical and physiological predictors of aVSP and DCI. Multivariate logistic regression models were used to develop and validate a risk scoring tool for each outcome. RESULTS Sixty-two percent of patients developed aVSP, and 19% developed DCI. Patients with aVSP had higher transfer function gain (1.06±0.33 versus 0.89±0.30; P=0.04) and patients with DCI had lower transfer function phase (17.5±39.6 versus 38.3±18.2; P=0.03) compared with those who did not develop either. Multivariable scoring tools using transfer function gain>0.98 and phase<12.5 were strongly predictive of aVSP (92% positive predictive value; 77% negative predictive value; area under the receiver operating characteristic curve, 0.92) and DCI (80% positive predictive value; 91% negative predictive value; area under the curve, 0.94), respectively. CONCLUSIONS Dynamic cerebral autoregulation is impaired in the early days after SAH. Including autoregulation as part of the initial clinical and radiographic assessment may enhance our ability to identify patients at a high risk for developing secondary complications after SAH.
Collapse
Affiliation(s)
- Fadar Otite
- From the Department of Neurology, Stroke Division (F.O., S.M., A.M., S.C., S.O., F.A.S.), Department of Radiology (A.A.Z.), and Department of Neurosurgery (R.D.), Brigham and Women's Hospital, Boston, MA; Cardiovascular Research Laboratory and Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, MA (C.O.T.); Institute for Aging Research, Hebrew SeniorLife, Roslindale, MA (S.P.); Harvard Medical School, Boston, MA (F.O., C.O.T., A.A.Z., A.M., S.C., S.O., S.P., R.D., F.A.S.); Department of Neurology, Klinikum Worms, Teaching Hospital of Mainz, Germany (S.M.); and Division of Neuroimaging and Neurointervention, Department of Radiology, University of Massachusetts Medical Center, Worcester, MA (A.P.)
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
66
|
Wellenius GA, Boyle LD, Wilker EH, Sorond FA, Coull BA, Koutrakis P, Mittleman MA, Lipsitz LA. Ambient fine particulate matter alters cerebral hemodynamics in the elderly. Stroke 2013; 44:1532-6. [PMID: 23709640 DOI: 10.1161/strokeaha.111.000395] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND AND PURPOSE Short-term elevations in fine particulate matter air pollution (PM2.5) are associated with increased risk of acute cerebrovascular events. Evidence from the peripheral circulation suggests that vascular dysfunction may be a central mechanism. However, the effects of PM2.5 on cerebrovascular function and hemodynamics are unknown. METHODS We used transcranial Doppler ultrasound to measure beat-to-beat blood flow velocity in the middle cerebral artery at rest and in response to changes in end-tidal CO2 (cerebral vasoreactivity) and arterial blood pressure (cerebral autoregulation) in 482 participants from the Maintenance of Balance, Independent Living, Intellect, and Zest in the Elderly (MOBILIZE) of Boston study. We used linear mixed effects models with random subject intercepts to evaluate the association between cerebrovascular hemodynamic parameters and mean PM2.5 levels 1 to 28 days earlier adjusting for age, race, medical history, meteorologic covariates, day of week, temporal trends, and season. RESULTS An interquartile range increase (3.0 µg/m(3)) in mean PM2.5 levels during the previous 28 days was associated with an 8.6% (95% confidence interval, 3.7%-13.8%; P<0.001) higher cerebral vascular resistance and a 7.5% (95% confidence interval, 4.2%-10.6%; P<0.001) lower blood flow velocity at rest. Measures of cerebral vasoreactivity and autoregulation were not associated with PM2.5 levels. CONCLUSIONS In this cohort of community-dwelling seniors, exposure to PM2.5 was associated with higher resting cerebrovascular resistance and lower cerebral blood flow velocity. If replicated, these findings suggest that alterations in cerebrovascular hemodynamics may underlie the increased risk of particle-related acute cerebrovascular events.
Collapse
|
67
|
Sorond FA, Hurwitz S, Salat DH, Greve DN, Fisher NDL. Neurovascular coupling, cerebral white matter integrity, and response to cocoa in older people. Neurology 2013; 81:904-9. [PMID: 23925758 DOI: 10.1212/wnl.0b013e3182a351aa] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE To investigate the relationship between neurovascular coupling and cognitive function in elderly individuals with vascular risk factors and to determine whether neurovascular coupling could be modified by cocoa consumption. METHODS Sixty older people (aged 72.9 ± 5.4 years) were studied in a parallel-arm, double-blind clinical trial of neurovascular coupling and cognition in response to 24 hours and 30 days of cocoa consumption. Cognitive measures included Mini-Mental State Examination and Trail Making Test A and B. Neurovascular coupling was measured from the beat-to-beat blood flow velocity responses in the middle cerebral arteries to the N-Back Task. In a subset of MRI-eligible participants, cerebral white matter structural integrity was also measured. RESULTS Neurovascular coupling was associated with Trails B scores (p = 0.002) and performance on the 2-Back Task. Higher neurovascular coupling was also associated with significantly higher fractional anisotropy in cerebral white matter hyperintensities (p = 0.02). Finally, 30 days of cocoa consumption was associated with increased neurovascular coupling (5.6% ± 7.2% vs -2.4% ± 4.8%; p = 0.001) and improved Trails B times (116 ± 78 seconds vs 167 ± 110 seconds; p = 0.007) in those with impaired neurovascular coupling at baseline. CONCLUSION There is a strong correlation between neurovascular coupling and cognitive function, and both can be improved by regular cocoa consumption in individuals with baseline impairments. Better neurovascular coupling is also associated with greater white matter structural integrity.
Collapse
Affiliation(s)
- Farzaneh A Sorond
- Department of Neurology, Stroke Division, Brigham and Women's Hospital, Boston, MA, USA
| | | | | | | | | |
Collapse
|
68
|
Purkayastha S, Fadar O, Mehregan A, Lipsitz LA, Sorond FA. Association between Cerebral tissue Structural Integrity and Dynamic Cerebral Autoregulation in Elderly Individuals. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1203.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sushmita Purkayastha
- Institute For Aging Research, Hebrew SeniorLifeBostonMA
- Harvard Medical SchoolBostonMA
| | - Otite Fadar
- Department of NeurologyBrigham and Women's HospitalBostonMA
| | - Aujan Mehregan
- Department of NeurologyBrigham and Women's HospitalBostonMA
| | - Lewis A Lipsitz
- Institute For Aging Research, Hebrew SeniorLifeBostonMA
- Harvard Medical SchoolBostonMA
| | - Farzaneh A Sorond
- Harvard Medical SchoolBostonMA
- Department of NeurologyBrigham and Women's HospitalBostonMA
| |
Collapse
|
69
|
Otite F, Sorond FA, Tan CO. Assessment of cerebral autoregulation as a clinical prognostic tool in subarachnoid hemorrhage. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.925.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Fadar Otite
- NeurologyBrigham and Women's Hospital and Harvard Medical SchoolBostonMA
| | - Farzaneh A. Sorond
- NeurologyBrigham and Women's Hospital and Harvard Medical SchoolBostonMA
| | - Can Ozan Tan
- Physical Medicine and RehabilitationSpaulding Rehabilitation Hospital and Harvard Medical SchoolCambridgeMA
| |
Collapse
|
70
|
Chou SH, Kuruppu S, Feske SK, Suh S, Orzell S, Henderson GV, Sorond FA, Du R, Smith IA, Lo EH, Ning M. Abstract WMP114: Increased Big Endothelin-1 in Human Cerebrospinal Fluid is Associated with Vasospasm and Poor 3-month Outcome Following Subarachnoid Hemorrhage. Stroke 2013. [DOI: 10.1161/str.44.suppl_1.awmp114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background
Big endothelin (ET) is the precursor to ET-1, a potent vasoconstrictive peptide associated with vasospasm (VSP) in SAH. However, ET-1’s very short half-life limits its utility as a clinical biomarker. Big ET mediates in vitro microvascular vasoconstriction and has slower clearance, therefore may be a better candidate biomarker. We hypothesize that elevated CSF Big ET-1 is associated with VSP and poor outcome in SAH.
Methods
We prospectively enrolled consecutive SAH subjects, banked serial CSF samples, and evaluated their modified Rankin scores (mRS) via telephone follow-up every 3 months. Poor functional outcome was defined as mRS>2. Angiographic VSP was defined as >50% reduction in caliber of any vessel on post-SAH day 7 cerebral angiogram. In 49 SAH subjects, we compared CSF big ET by ELISA on post-SAH days 1, 3, 5, and 7 with respect to VSP and outcome using student’s t-test or Wilcoxon rank sum test depending on data normality. Logistic regression was used to adjust for important confounders.
Results
CSF big ET elevation on post-SAH day 1 is associated with poor 3-month outcome (4.2 vs. 2.0 ng/mL, p=0.0048), and big ET elevation on post-SAH day 3 shows trend towards association with poor 3-month outcome (1.15 vs. 3.09 pg/mL, p=0.057). CSF big ET level on post-SAH day 1 is significantly associated with 3-month outcome (p<0.0001) after adjusting for age, Hunt and Hess (HH) and Fisher grades and aneurysm treatment modality by logistic regression. CSF big ET elevation on post-SAH day 7 is associated with VSP (5.2 vs. 3.9 pg/mL, p=0.045). Logistic regression shows CSF big ET level on post-SAH day 7 is significantly associated with VSP (p=0.02) after adjusting for age, HH and Fisher grades and aneurysm treatment modality.
Conclusion
Early elevation of CSF big ET is strongly and independently associated with SAH 3-month outcome after adjustment for important clinical confounders. CSF big ET elevation on post-SAH day 7 is also independently associated with angiographic VSP. A larger study with a replication cohort is necessary to validate big ET as a biomarker for SAH outcome and VSP. Further studies with concomitant measurements of endothelin-converting enzyme and ET-1 are necessary to elucidate the role of CSF big ET in VSP and brain injury following SAH.
Collapse
Affiliation(s)
- Sherry H Chou
- Brigham and Women’s Hosp; Harvard Med Sch, Boston, MA
| | | | | | - Sarah Suh
- Brigham and Women’s Hosp, Boston, MA
| | | | | | | | - Rose Du
- Brigham and Women’s Hosp; Harvard Med Sch, Boston, MA
| | | | - Eng H Lo
- Massachusetts General Hosp; Harvard Med Sch, Boston, MA
| | - MingMing Ning
- Massachusetts General Hosp; Harvard Med Sch, Boston, MA
| |
Collapse
|
71
|
Nakagawa K, Serrador JM, LaRose SL, Sorond FA. Dynamic cerebral autoregulation after intracerebral hemorrhage: A case-control study. BMC Neurol 2011; 11:108. [PMID: 21884574 PMCID: PMC3175166 DOI: 10.1186/1471-2377-11-108] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Accepted: 08/31/2011] [Indexed: 11/26/2022] Open
Abstract
Background Dynamic cerebral autoregulation after intracerebral hemorrhage (ICH) remains poorly understood. We performed a case-control study to compare dynamic autoregulation between ICH patients and healthy controls. Methods Twenty-one patients (66 ± 15 years) with early (< 72 hours) lobar or basal ganglia ICH were prospectively studied and compared to twenty-three age-matched controls (65 ± 9 years). Continuous measures of mean flow velocity (MFV) in the middle cerebral artery and mean arterial blood pressure (MAP) were obtained over 5 min. Cerebrovascular resistance index (CVRi) was calculated as the ratio of MAP to MFV. Dynamic cerebral autoregulation was assessed using transfer function analysis of spontaneous MAP and MFV oscillations in the low (0.03-0.15 Hz) and high (0.15-0.5 Hz) frequency ranges. Results The ICH group demonstrated higher CVRi compared to controls (ipsilateral: 1.91 ± 1.01 mmHg·s·cm-1, p = 0.04; contralateral: 2.01 ± 1.24 mmHg·s·cm-1, p = 0.04; vs. control: 1.42 ± 0.45 mmHg·s·cm-1). The ICH group had higher gains than controls in the low (ipsilateral: 1.33 ± 0.58%/mmHg, p = 0.0005; contralateral: 1.47 ± 0.98%/mmHg, p = 0.004; vs. control: 0.82 ± 0.30%/mmHg) and high (ipsilateral: 2.11 ± 1.31%/mmHg, p < 0.0001; contralateral: 2.14 ± 1.49%/mmHg, p < 0.0001; vs. control: 0.66 ± 0.26%/mmHg) frequency ranges. The ICH group also had higher coherence in the contralateral hemisphere than the control (ICH contralateral: 0.53 ± 0.38, p = 0.02; vs. control: 0.38 ± 0.15) in the high frequency range. Conclusions Patients with ICH had higher gains in a wide range of frequency ranges compared to controls. These findings suggest that dynamic cerebral autoregulation may be less effective in the early days after ICH. Further study is needed to determine the relationship between hematoma size and severity of autoregulation impairment.
Collapse
Affiliation(s)
- Kazuma Nakagawa
- Neuroscience Institute, The Queen's Medical Center, Honolulu, Hawaii, USA.
| | | | | | | |
Collapse
|
72
|
Sorond FA, Kiely DK, Galica A, Moscufo N, Serrador JM, Iloputaife I, Egorova S, Dell'Oglio E, Meier DS, Newton E, Milberg WP, Guttmann CRG, Lipsitz LA. Neurovascular coupling is impaired in slow walkers: the MOBILIZE Boston Study. Ann Neurol 2011; 70:213-20. [PMID: 21674588 DOI: 10.1002/ana.22433] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 03/03/2011] [Accepted: 03/18/2011] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Neurovascular coupling may be involved in compensatory mechanisms responsible for preservation of gait speed in elderly people with cerebrovascular disease. Our study examines the association between neurovascular coupling in the middle cerebral artery and gait speed in elderly individuals with impaired cerebral vasoreactivity. METHODS Twenty-two fast and 20 slow walkers in the lowest quartile of cerebral vasoreactivity were recruited from the MOBILIZE Boston Study. Neurovascular coupling was assessed in bilateral middle cerebral arteries by measuring cerebral blood flow during the N-Back task. Cerebral white matter hyperintensities were measured for each group using magnetic resonance imaging. RESULTS Neurovascular coupling was attenuated in slow compared to fast walkers (2.8%; 95% confidence interval [CI], -0.9 to 6.6 vs 8.2%; 95% CI, 4.7-11.8; p = 0.02). The odds ratio of being a slow walker was 6.4 (95% CI, 1.7-24.9; p = 0.007) if there was a high burden of white matter hyperintensity; however, this risk increased to 14.5 (95% CI, 2.3-91.1; p = 0.004) if neurovascular coupling was also attenuated. INTERPRETATION Our results suggest that intact neurovascular coupling may help preserve mobility in elderly people with cerebral microvascular disease.
Collapse
Affiliation(s)
- Farzaneh A Sorond
- Department of Neurology, Stroke Division, Brigham and Women's Hospital, Women's Hospital, Boston, MA 02115, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
73
|
Abstract
BACKGROUND AND PURPOSE Orthostatic intolerance and falls differ between sexes and change with age. However, it remains unclear what role cerebral autoregulation may play in this response. This study was designed to determine whether cerebral autoregulation, assessed using transcranial Doppler ultrasound, is more effective in elderly females than in males. METHODS We used transcranial Doppler ultrasound to evaluate cerebral autoregulation in 544 (236 male) subjects older than age 70 years recruited as part of the MOBILIZE Boston study. The MOBILIZE Boston study is a prospective cohort study of a unique set of risk factors for falls in seniors in the Boston area. We assessed CO2 reactivity and transfer function gain, phase, and coherence during 5 minutes of quiet sitting and autoregulatory index during sit-to-stand tests. RESULTS Male subjects had significantly lower CO2 reactivity (males, 1.10 ± 0.03; females, 1.32 ± 0.43 (cm/s)/%CO2; P<0.001) and autoregulatory indices (males, 4.41 ± 2.44; female, 5.32 ± 2.47; P<0.001), higher transfer function gain (males, 1.34 ± 0.49; females, 1.19 ± 0.43; P=0.002), and lower phase (males, 42.7 ± 23.6; females, 49.4 ± 24.9; P=0.002) in the autoregulatory band, implying less effective cerebral autoregulation. However, reduced autoregulation in males was not below the normal range, indicating autoregulation was intact but less effective. CONCLUSIONS Female subjects were better able to maintain cerebral flow velocities during postural changes and demonstrated better cerebral autoregulation. The mechanisms of sex-based differences in autoregulation remain unclear but may partially explain the higher rates of orthostatic hypotension-related hospitalizations in elderly men.
Collapse
Affiliation(s)
- Brian M Deegan
- Electrical & Electronic Engineering, School of Engineering & Informatics, NUI Galway, University Road, Galway, Ireland
| | | | | | | | | | | |
Collapse
|
74
|
Deegan BM, Serrador JM, Nakagawa K, Jones E, Sorond FA, Olaighin G. The effect of blood pressure calibrations and transcranial Doppler signal loss on transfer function estimates of cerebral autoregulation. Med Eng Phys 2011; 33:553-62. [PMID: 21239208 DOI: 10.1016/j.medengphy.2010.12.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 11/26/2010] [Accepted: 12/13/2010] [Indexed: 11/16/2022]
Abstract
There are methodological concerns with combined use of transcranial Doppler (TCD) and Finapres to measure dynamic cerebral autoregulation. The Finapres calibration mechanism ("physiocal") causes interruptions to blood pressure recordings. Also, TCD is subject to signal loss due to probe movement. We assessed the effects of "physiocals" and TCD signal loss on transfer function estimates in recordings of 45 healthy subjects. We added artificial "physiocals" and removed sections of TCD signal from 5 min Finapres and TCD recordings. We also compared transfer function results from 5 min time series with time series as short as 1 min. Accurate transfer function estimates can be achieved in the 0.03-0.07 Hz band using beat-by-beat data with linear interpolation, while data loss is less than 10s. At frequencies between 0.07 and 0.5 Hz, transfer function estimates become unreliable with 5s of data loss every 50s. 2s data loss only affects frequency bands above 0.15Hz. Finally, accurate transfer function assessment of autoregulatory function can be achieved from time series as short as 1min, although gain and coherence tend to be overestimated at higher frequencies.
Collapse
Affiliation(s)
- Brian M Deegan
- Electrical & Electronic Engineering, NUI Galway, University Road, Galway, Ireland.
| | | | | | | | | | | |
Collapse
|
75
|
Abstract
BACKGROUND The assumption is often made that aggressive care in the form of early decompressive hemicraniectomy is appropriate for young patients who suffer a massive stroke. However, neither their attitude toward aggressive treatment, nor their perception of acceptable quality of life after a stroke, has been adequately studied. METHODS We conducted a cross-sectional questionnaire-based survey that consisted of demographic information and attitude toward neurological disability based on the highest acceptable modified Rankin Scale (mRS) that they would be "willing to live with." Young adults in the Los Angeles County were surveyed and grouped by whether or not they would want early decompressive hemicraniectomy after a massive stroke. Logistic regression analysis was used to determine the factors associated with willingness to accept decompressive hemicraniectomy. RESULTS Sixty-eight community-dwelling young adults (mean age: 24 +/- 6 years) were surveyed. The highest acceptable mRS (0-5) participants felt "willing to live with" were: 10.3% (0), 29.4% (1), 27.9% (2), 20.6% (3), 8.8% (4), 2.9% (5). Despite being presented with a hypothetical high likelihood of long-term disability, 46 of 68 (68%) reported they would undergo hemicraniectomy. Neither the demographic factors nor the highest acceptable mRS was associated with the willingness to seek decompressive hemicraniectomy. CONCLUSION Our study supports the commonly held assumption that the majority of young adults would favor early decompressive hemicraniectomy after a massive ischemic stroke. We also show that a substantial minority in this age group is reluctant to accept this aggressive measure, emphasizing the importance of discussing the individual's previously stated wishes, even in the young population.
Collapse
Affiliation(s)
- Kazuma Nakagawa
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| | | | | | | |
Collapse
|
76
|
Sorond FA, Hollenberg NK, Panych LP, Fisher NDL. Brain blood flow and velocity: correlations between magnetic resonance imaging and transcranial Doppler sonography. J Ultrasound Med 2010; 29:1017-1022. [PMID: 20587424 PMCID: PMC2906813 DOI: 10.7863/jum.2010.29.7.1017] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
OBJECTIVE Because transcranial Doppler sonography (TCD) is unable to measure arterial diameter, it remains unproven whether the changes in cerebral blood velocity it measures are representative of changes in cerebral blood flow (CBF). Our study was designed to compare velocity changes with flow changes measured by two magnetic resonance imaging (MRI) techniques, perfusion MRI and arterial spin labeling (ASL), using flavanol-rich cocoa to induce CBF changes in healthy volunteers. METHODS We enrolled 20 healthy volunteers aged 62 to 80 years (mean, 73 years). Each was studied at baseline and after drinking standardized servings of cocoa for 7 to 14 days. RESULTS Changes in middle cerebral artery (MCA) flow by TCD were significantly correlated with changes in perfusion assessed by gadolinium-enhanced MRI (r = 0.63; P < .03). Measurements with ASL showed a stronger correlation with borderline significance. CONCLUSIONS Changes in flow velocity in the MCA associated with drinking cocoa were highly correlated with changes in CBF measured by the two MRI techniques using the tracer gadolinium and ASL. These results validate Doppler measurements of CBF velocity as representative assessments of CBF.
Collapse
Affiliation(s)
- Farzaneh A Sorond
- Department of Neurology, Stroke Division, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02117, USA.
| | | | | | | |
Collapse
|
77
|
Sorond FA, Galica A, Serrador JM, Kiely DK, Iloputaife I, Cupples LA, Lipsitz LA. Cerebrovascular hemodynamics, gait, and falls in an elderly population: MOBILIZE Boston Study. Neurology 2010; 74:1627-33. [PMID: 20479362 DOI: 10.1212/wnl.0b013e3181df0982] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine whether alterations in cerebral blood flow regulation are associated with slow gait speed and falls in community-dwelling elderly individuals. METHODS The study sample consisted of 419 individuals from the MOBILIZE Boston Study (MBS) who had transcranial Doppler ultrasound measures of cerebral blood flow velocity. The MBS is a prospective cohort study of a unique set of risk factors for falls in seniors in the Boston area. We measured beat-to-beat blood flow velocity in the middle cerebral artery in response to 1) changes in end-tidal CO(2) (cerebral vasoreactivity) and 2) blood pressure changes during a sit-to-stand protocol (cerebral autoregulation). Gait speed was measured during a 4-meter walk. Falls were tracked by monthly calendars, and demographic and clinical characteristics were assessed at baseline. RESULTS A multivariate linear regression analysis showed that cerebral vasoreactivity was cross-sectionally related to gait speed (p = 0.039). Individuals in the lowest quintile of vasoreactivity had lower gait speeds as compared to those in the highest quintile (p = 0.047). In a negative binomial regression analysis adjusted for relevant covariates, the relationship between cerebral vasoreactivity and fall rate did not reach significance. However, when comparing individuals in the lowest to highest quintile of cerebral vasoreactivity, those in the lowest quintile had a higher fall rate (p = 0.029). CONCLUSIONS Impaired cerebral blood flow regulation, as measured by cerebral vasoreactivity to CO(2), is associated with slow gait speed and may lead to the development of falls in elderly people.
Collapse
Affiliation(s)
- F A Sorond
- Department of Neurology, Stroke Division, Brigham and Women's Hospital, 45 Francis St., Boston, MA 02115, USA.
| | | | | | | | | | | | | |
Collapse
|
78
|
Deegan BM, Sorond FA, Lipsitz LA, Olaighin G, Serrador JM. Gender related differences in cerebral autoregulation in older healthy subjects. Annu Int Conf IEEE Eng Med Biol Soc 2010; 2009:2859-62. [PMID: 19964277 DOI: 10.1109/iembs.2009.5333604] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cerebral autoregulation is an intrinsic mechanism of the cerebrovasculature that maintains cerebral blood flow relatively constant over a wide range of blood pressures. Recent studies have shown sex differences in cerebral autoregulation in adolescents and young adults. We evaluated cerebral auturegulation in 419 (186 male) subjects over the age of 70 recruited as part of the MOBILIZE Boston study. CO(2) reactivity, transfer function gain and autoregulatory index (ARI) during sit to stand tests were assessed. Female subjects had significantly higher CO(2) reactivity (p < 0.001) and vasomotor range (p<0.001) as well as ARI indices (p<0.001) and lower transfer function gain in the autoregulatory band (p=0.001), implying better cerebral autoregulation, than male subjects. The mechanisms of sex based differences in cerebral autoregulation remain unclear, but the results of this study highlight the need for future work to better understand these underlying autoregulatory differences.
Collapse
Affiliation(s)
- Brian M Deegan
- Department of Electrical & Electronic Engineering, School of Engineering & Informatics, NUI Galway, University Road, Galway, Ireland.
| | | | | | | | | |
Collapse
|
79
|
Galica AM, Kang HG, Priplata AA, D’Andrea SE, Starobinets OV, Sorond FA, Cupples LA, Lipsitz LA. Subsensory vibrations to the feet reduce gait variability in elderly fallers. Gait Posture 2009; 30:383-7. [PMID: 19632845 PMCID: PMC2745077 DOI: 10.1016/j.gaitpost.2009.07.005] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Revised: 06/15/2009] [Accepted: 07/03/2009] [Indexed: 02/02/2023]
Abstract
The purpose of this study was to investigate the effect of subsensory vibratory noise applied to the soles of the feet on gait variability in a population of elderly recurrent fallers compared to non-fallers and young controls. Eighteen elderly recurrent fallers and 18 elderly non-fallers were recruited from the MOBILIZE Boston Study (MBS), a population-based cohort study investigating novel risk factors for falls. Twelve young participants were included as controls. Participants performed three 6-min walking trials while wearing a pair of insoles containing vibrating actuators. During each trial, the noise stimulus was applied for 3 of the 6min, and differences in stride, stance, and swing time variability were analyzed between noise and no-noise conditions. The use of vibrating insoles significantly reduced stride, stance, and swing time variability measures for elderly recurrent fallers. Elderly non-fallers also demonstrated significant reductions in stride and stance time variability. Although young participants showed decreases in all variability measures, the results did not achieve statistical significance. Gait variability reductions with noise were similar between the elderly recurrent fallers and elderly non-fallers. This study supports the hypothesis that subsensory vibratory noise applied to the soles of the feet can reduce gait variability in elderly participants. Future studies are needed to determine if this intervention reduces falls risk.
Collapse
Affiliation(s)
- Andrew M. Galica
- Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts
| | - Hyun Gu Kang
- Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts,Harvard Medical School, Boston, Massachusetts,Gerontology Division, Beth Israel Deaconess Medical Center, Boston, Massachusetts,Department of Biomedical Engineering Boston University, Boston, Massachusetts
| | | | - Susan E. D’Andrea
- The Center for Restorative and Regenerative Medicine, Providence VA Medical Center/Brown University, Providence, Rhode Island
| | | | - Farzaneh A. Sorond
- Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts,Department of Neurology, Division of Critical Care and Stroke, Brigham and Woman’s Hospital, Boston, Massachusetts
| | - L. Adrienne Cupples
- Departments of Biostatistics and Epidemiology, Boston University, Boston, Massachusetts
| | - Lewis A. Lipsitz
- Institute for Aging Research, Hebrew SeniorLife, Boston, Massachusetts,Harvard Medical School, Boston, Massachusetts,Gerontology Division, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| |
Collapse
|
80
|
Affiliation(s)
- Susanne Muehlschlegel
- UMass Memorial Medical Center, University Campus, University of Massachusetts Medical School, 55 Lake Ave N, Worcester, MA 01655, USA.
| | | | | |
Collapse
|
81
|
Rudolph JL, Sorond FA, Pochay VE, Haime M, Treanor P, Crittenden MD, Babikian VL. Cerebral hemodynamics during coronary artery bypass graft surgery: the effect of carotid stenosis. Ultrasound Med Biol 2009; 35:1235-1241. [PMID: 19540657 PMCID: PMC2755299 DOI: 10.1016/j.ultrasmedbio.2009.04.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2008] [Revised: 03/09/2009] [Accepted: 04/09/2009] [Indexed: 05/27/2023]
Abstract
Carotid stenosis is a frequent coexisting condition in patients undergoing coronary artery bypass graft (CABG) surgery. The impact of carotid stenosis on cerebral perfusion is not fully understood. The purpose of this study was to determine the impact of carotid stenosis on cerebral blood flow velocity in patients undergoing CABG. Seventy-three patients undergoing CABG were prospectively recruited and underwent preoperative Duplex carotid ultrasound to evaluate the degree of carotid stenosis. Intraoperatively, transcranial Doppler ultrasound was used to record the mean flow velocity (MFV) within the bilateral middle cerebral arteries. In addition, during the period of cardiopulmonary bypass, regulators of cerebral hemodynamics such as hematocrit, partial pressure of carbon dioxide and temperature were recorded. The ipsilateral middle cerebral artery mean flow velocity was compared in arteries with and without carotid stenosis using a repeated measures analysis. Seventy-three patients underwent intraoperative monitoring during CABG and 30% (n=22) had carotid stenosis. Overall, MFV rose throughout the duration of CABG including when the patient was on cardiopulmonary bypass. However, there was no significant MFV difference between those arteries with and without stenosis (F=1.2, p=.21). Further analysis during cardiopulmonary bypass, demonstrated that hemodilution and partial pressure of carbon dioxide may play a role in cerebral autoregulation during CABG. Carotid stenosis did not impact mean cerebral blood flow velocity during CABG. The cerebrovascular regulatory process appears to be largely intact during CABG.
Collapse
Affiliation(s)
- James L Rudolph
- Geriatric Research, Education, and Clinical Center, Boston, MA 02130, USA.
| | | | | | | | | | | | | |
Collapse
|
82
|
Nakagawa K, Serrador JM, Larose SL, Moslehi F, Lipsitz LA, Sorond FA. Autoregulation in the posterior circulation is altered by the metabolic state of the visual cortex. Stroke 2009; 40:2062-7. [PMID: 19359628 DOI: 10.1161/strokeaha.108.545285] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND AND PURPOSE Previous studies suggest that dynamic autoregulation in the posterior cerebral artery (PCA) is less efficient compared to the middle cerebral artery (MCA). We examined the role of cerebral vasodilation caused by metabolic activation (ie, visual stimulus) on autoregulatory characteristics in the 2 vascular territories. METHODS Blood flow velocity in the PCA and MCA and mean arterial pressure were measured continuously in 45 healthy volunteers (62+/-3 years) while seated with eyes open. Additional 20 subjects (60+/-5 years) were examined with eyes closed and open. Autoregulation was assessed using transfer function gains in both the PCA and MCA territories in the low (0.03-0.07 Hz), high (0.07-0.15 Hz), and cardiac (approximately 1 Hz) frequency ranges. RESULTS With eyes open, gains were significantly higher in the PCA compared to the MCA in the low (PCA: 1.41+/-0.09 vs MCA: 1.18+/-0.07; P=0.003) and high (PCA: 2.06+/-0.12 vs MCA: 1.61+/-0.08; P=0.0001) frequencies. Opening eyes increased blood flow velocity and reduced cerebrovascular resistance index in the PCA but not in MCA. This vasodilation in the PCA was associated with increased gain in the low (autoregulatory) frequency, whereas MCA gain did not change (PCA: 0.89+/-0.14 vs 1.31+/-0.17, MCA: 1.24+/-0.16 vs 1.16+/-0.11; P=0.02). CONCLUSIONS Dilation of the PCA territory during visual cortex activation resulted in increased PCA transfer function gain without changing MCA gain. Thus, impaired autoregulation in the PCA reported in previous literature is likely the result of metabolic vasodilation and not an inherent difference in the autoregulatory characteristics of the posterior circulation.
Collapse
Affiliation(s)
- Kazuma Nakagawa
- Department of Neurology, Stroke Division, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
| | | | | | | | | | | |
Collapse
|
83
|
Sorond FA, Serrador JM, Jones RN, Shaffer ML, Lipsitz LA. The sit-to-stand technique for the measurement of dynamic cerebral autoregulation. Ultrasound Med Biol 2009; 35:21-9. [PMID: 18834658 PMCID: PMC2680703 DOI: 10.1016/j.ultrasmedbio.2008.08.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2008] [Revised: 07/16/2008] [Accepted: 08/01/2008] [Indexed: 05/08/2023]
Abstract
Measurement of cerebral autoregulation is important for the evaluation and management of a number of clinical disorders that affect cerebral blood flow. We currently lack simple bedside measures that mimic common physiologic stresses. Therefore, we evaluated a new sit-to-stand technique as an alternative method to the frequently-used thigh-cuff technique in healthy volunteers. Continuous middle cerebral artery (MCA) blood flow velocities (BFV) and arterial blood pressure (ABP) were measured in response to standing from a sitting position, or rapid thigh-cuff deflation in 24 healthy subjects (50 +/- 22 y). Autoregulatory index (ARI) was calculated as the BFV response for step changes in ABP using a second-order differential equation with a set of parameters that can be used to grade the performance of autoregulation. Of these 24 subjects, 30% could tolerate only two thigh-cuffs and refused to proceed with the third cuff, whereas none of our subjects had any difficulty with performing the three sit-to-stand trials. The two techniques produced similar changes in mean ABP, but the times to nadir of the blood pressure and BFV were significantly faster for the thigh-cuff. The mean group ARIs were similar between the two techniques. Although between-subjects variability was higher for sit-to-stand ARIs, the within-subject sit-to-stand ARI variability was small. Thus, for the assessment of cerebral autoregulation, the sit-to-stand procedure is well tolerated and produces ARI values that have low within-subject variability. The sit-to-stand technique appears to be a suitable measure of individual ARI values for inferring dynamic cerebral autoregulation.
Collapse
Affiliation(s)
- Farzaneh A Sorond
- Department of Neurology, Stroke Division, Brigham and Women's Hospital, Boston, MA 02115, USA.
| | | | | | | | | |
Collapse
|
84
|
Leveille SG, Kiel DP, Jones RN, Roman A, Hannan MT, Sorond FA, Kang HG, Samelson EJ, Gagnon M, Freeman M, Lipsitz LA. The MOBILIZE Boston Study: design and methods of a prospective cohort study of novel risk factors for falls in an older population. BMC Geriatr 2008; 8:16. [PMID: 18638389 PMCID: PMC2500010 DOI: 10.1186/1471-2318-8-16] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Accepted: 07/18/2008] [Indexed: 11/24/2022] Open
Abstract
Background Falls are the sixth leading cause of death in elderly people in the U.S. Despite progress in understanding risk factors for falls, many suspected risk factors have not been adequately studied. Putative risk factors for falls such as pain, reductions in cerebral blood flow, somatosensory deficits, and foot disorders are poorly understood, in part because they pose measurement challenges, particularly for large observational studies. Methods The MOBILIZE Boston Study (MBS), an NIA-funded Program Project, is a prospective cohort study of a unique set of risk factors for falls in seniors in the Boston area. Using a door-to-door population-based recruitment, we have enrolled 765 persons aged 70 and older. The baseline assessment was conducted in 2 segments: a 3-hour home interview followed within 4 weeks by a 3-hour clinic examination. Measures included pain, cerebral hemodynamics, and foot disorders as well as established fall risk factors. For the falls follow-up, participants return fall calendar postcards to the research center at the end of each month. Reports of falls are followed-up with a telephone interview to assess circumstances and consequences of each fall. A second assessment is performed 18 months following baseline. Results Of the 2382 who met all eligibility criteria at the door, 1616 (67.8%) agreed to participate and were referred to the research center for further screening. The primary reason for ineligibility was inability to communicate in English. Results from the first 600 participants showed that participants are largely representative of seniors in the Boston area in terms of age, sex, race and Hispanic ethnicity. The average age of study participants was 77.9 years (s.d. 5.5) and nearly two-thirds were women. The study cohort was 78% white and 17% black. Many participants (39%) reported having fallen at least once in the year before baseline. Conclusion Our results demonstrate the feasibility of conducting comprehensive assessments, including rigorous physiologic measurements, in a diverse population of older adults to study non-traditional risk factors for falls and disability. The MBS will provide an important new data resource for examining novel risk factors for falls and mobility problems in the older population.
Collapse
Affiliation(s)
- Suzanne G Leveille
- Division of General Medicine and Primary Care, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
85
|
|
86
|
Sorond FA, Lipsitz LA, Hollenberg NK, Fisher NDL. Cerebral blood flow response to flavanol-rich cocoa in healthy elderly humans. Neuropsychiatr Dis Treat 2008; 4:433-40. [PMID: 18728792 PMCID: PMC2518374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND AND PURPOSE Cerebral ischemia is a common, morbid condition accompanied by cognitive decline. Recent reports on the vascular health benefits of flavanol-containing foods signify a promising approach to the treatment of cerebral ischemia. Our study was designed to investigate the effects of flavanol-rich cocoa (FRC) consumption on cerebral blood flow in older healthy volunteers. METHODS We used transcranial Doppler (TCD) ultrasound to measure mean blood flow velocity (MFV) in the middle cerebral artery (MCA) in thirty-four healthy elderly volunteers (72 +/- 6 years) in response to the regular intake of FRC or flavanol-poor cocoa (FPC). RESULTS In response to two weeks of FRC intake, MFV increased by 8% +/- 4% at one week (p = 0.01) and 10% +/- 4% (p = 0.04) at two weeks. In response to one week of cocoa, significantly more subjects in the FRC as compared with the FPC group had an increase in their MFV (p < 0.05). CONCLUSIONS In summary, we show that dietary intake of FRC is associated with a significant increase in cerebral blood flow velocity in the MCA as measured by TCD. Our data suggest a promising role for regular cocoa flavanol's consumption in the treatment of cerebrovascular ischemic syndromes, including dementias and stroke.
Collapse
Affiliation(s)
- Farzaneh A Sorond
- Department of Neurology, Stroke Division, 45 Francis St, Boston, MA 02115, USA.
| | | | | | | |
Collapse
|
87
|
Sorond FA, Schnyer DM, Serrador JM, Milberg WP, Lipsitz LA. Cerebral blood flow regulation during cognitive tasks: effects of healthy aging. Cortex 2007; 44:179-84. [PMID: 18387547 DOI: 10.1016/j.cortex.2006.01.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Revised: 09/22/2005] [Accepted: 01/09/2006] [Indexed: 10/22/2022]
Abstract
Aging is associated with frontal subcortical microangiopathy and executive cognitive dysfunction, suggesting that elderly individuals may have impaired metabolic activation of cerebral blood flow to the frontal lobes. We used transcranial Doppler (TCD) ultrasound to examine the cerebral blood flow response to executive control and visual tasks in the anterior and posterior cerebral circulations and to determine the effects of healthy aging on cerebral blood flow regulation during cognitive tasks. Continuous simultaneous anterior cerebral artery (ACA) and posterior cerebral artery (PCA) blood flow velocities (BFVs) and mean arterial pressure (MAP) were measured in response to word stem completion (WSC) and a visual search (VS) task in 29 healthy subjects (14 young, 30+/-1.5 years; 15 old, 74+/-1.4 years). We found that: (1) ACA and PCA blood flow velocities are both significantly increased during WSC and VS cognitive tasks, (2) ACA and PCA activations were task specific in our young volunteers, with ACA>PCA BFV during the WSC task and PCA>ACA BFV during the VS task, (3) while healthy elderly subjects also had PCA>ACA BFV during the VS task, they did not have ACA>PCA activation during the WSC task, and (4) healthy elderly subjects tend to have overall greater increases in BFV during both cognitive tasks. We conclude that TCD can be used to monitor cerebrovascular hemodynamics during the performance of cognitive tasks. Our data suggest that there is differential blood flow increase in the ACA and PCA in young versus elderly subjects during cognitive tasks.
Collapse
Affiliation(s)
- Farzaneh A Sorond
- Department of Neurology, Stroke Division, Brigham and Women's Hospital, Institute for Aging Research, Hebrew SeniorLife, Harvard Medical School, Boston, MA 02115, USA.
| | | | | | | | | |
Collapse
|
88
|
Abstract
Foods and beverages rich in flavonoids are being heralded as potential preventive agents for a range of pathologic conditions, ranging from hypertension to coronary heart disease to stroke and dementia. We and others have demonstrated that short-term ingestion of cocoa, particularly rich in the subclass of flavonoids known as flavanols, induced a consistent and striking peripheral vasodilation in healthy people, improving endothelial function in a nitric oxide-dependent manner. The vasodilator response was reversed by N-nitro-L-arginine methyl ester, an arginine analog that blocks nitric oxide synthesis. Flavanol-poor cocoa induced much smaller responses. Because impairment of endothelial function is a nearly universal accompaniment of the aging process, we examined the peripheral vasodilator response to flavanol-rich cocoa in healthy older subjects. Observations point to a favorable response among the older. Together with peripheral vascular disease, cerebrovascular disease is responsible for significant mortality with advancing age. An association of decreased cerebral perfusion with dementia has been recently highlighted. The prospect of increasing cerebral perfusion with cocoa flavanols is extremely promising. Our still preliminary data hold out the promise that the cerebral blood supply in the elderly participates in the vasodilator response. With the modalities of transcranial Doppler and MRI, we have the capabilities of analyzing the potential benefits of flavanols on brain perfusion and, subsequently, on cognition.
Collapse
Affiliation(s)
- Naomi D L Fisher
- Department of Internal Medicine, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, USA.
| | | | | |
Collapse
|
89
|
Abstract
BACKGROUND We used transcranial Doppler ultrasonography to examine the cerebral blood flow response to orthostatic stress in the middle and posterior cerebral circulations and to determine the effects of healthy aging on regional cerebral blood flow regulation. METHODS Continuous simultaneous middle (MCA) and posterior (PCA) cerebral artery blood flow velocities (BFV) and mean arterial pressure (MAP) were measured in response to standing from a sitting position in 13 younger (30 +/- 7 years) and 13 older (73 +/- 4 years) healthy participants. RESULTS The older participants had a significantly larger decline in MAP (-31% +/- 3 in the older and -21% +/- 2 in the younger) and a smaller increase in heart rate (HR) (15 bpm +/- 1 in the older, 24 bpm +/- 2 in the younger) during the posture change. Despite a larger decline in MAP, the older participants had a decline very similar to that of the younger participants in BFVs in both vascular territories. This was associated with a significantly larger vasodilatory response in the MCA and PCA vascular territories of the older participants. There were no regional differences of the cerebrovascular resistance and BFV responses to orthostasis in the younger participants. However, in the older participants, there was a significantly larger BFV decline and a smaller vasodilatory response in the PCA as compared to the MCA territory. CONCLUSIONS Healthy aging is associated with preserved cerebrovascular adaptation to orthostatic hypotension. However, in older persons, the PCA territory blood flow may be more vulnerable to reduced perfusion during orthostatic stress.
Collapse
Affiliation(s)
- Farzaneh A Sorond
- Brigham and Women's Hospital, Neurology Stroke Division, 45 Francis St., Boston, MA 02115, USA.
| | | | | | | |
Collapse
|
90
|
Kuo HK, Sorond FA, Chen JH, Hashmi A, Milberg WP, Lipsitz LA. The role of homocysteine in multisystem age-related problems: a systematic review. J Gerontol A Biol Sci Med Sci 2005; 60:1190-201. [PMID: 16183962 DOI: 10.1093/gerona/60.9.1190] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Homocysteine is a sulfur-containing amino acid that is involved in one-carbon metabolism. Hyperhomocysteinemia is a common phenomenon among elderly people. There is growing evidence of an association between hyperhomocysteinemia and geriatric multisystem problems, including coronary artery disease, stroke, peripheral vascular disease, cognitive impairment, dementia, depression, osteoporotic fractures, and functional decline. The proposed mechanisms of the association include angiotoxicity, neurotoxicity, and inhibition of collagen cross-linking. A homocysteine-lowering strategy may prevent or slow the development of these age-related problems. Vitamin supplementation and folic acid fortification of grain foods have been shown to decrease plasma homocysteine concentrations. More research is needed to investigate whether lifelong homocysteine lowering can prevent the development of late-life morbidity.
Collapse
Affiliation(s)
- Hsu-Ko Kuo
- Hebrew Rehabilitation Center for Aged, 1200 Centre Street, Boston, Massachusetts 02131, USA
| | | | | | | | | | | |
Collapse
|
91
|
Serrador JM, Sorond FA, Vyas M, Gagnon M, Iloputaife ID, Lipsitz LA. Cerebral pressure-flow relations in hypertensive elderly humans: transfer gain in different frequency domains. J Appl Physiol (1985) 2004; 98:151-9. [PMID: 15361517 DOI: 10.1152/japplphysiol.00471.2004] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The dynamics of the cerebral vascular response to blood pressure changes in hypertensive humans is poorly understood. Because cerebral blood flow is dependent on adequate perfusion pressure, it is important to understand the effect of hypertension on the transfer of pressure to flow in the cerebrovascular system of elderly people. Therefore, we examined the effect of spontaneous and induced blood pressure changes on beat-to-beat and within-beat cerebral blood flow in three groups of elderly people: normotensive, controlled hypertensive, and uncontrolled hypertensive subjects. Cerebral blood flow velocity (transcranial Doppler), blood pressure (Finapres), heart rate, and end-tidal CO(2) were measured during the transition from a sit to stand position. Transfer function gains relating blood pressure to cerebral blood flow velocity were assessed during steady-state sitting and standing. Cerebral blood flow regulation was preserved in all three groups by using changes in cerebrovascular resistance, transfer function gains, and the autoregulatory index as indexes of cerebral autoregulation. Hypertensive subjects demonstrated better attenuation of cerebral blood flow fluctuations in response to blood pressure changes both within the beat (i.e., lower gain at the cardiac frequency) and in the low-frequency range (autoregulatory, 0.03-0.07 Hz). Despite a better pressure autoregulatory response, hypertensive subjects demonstrated reduced reactivity to CO(2). Thus otherwise healthy hypertensive elderly subjects, whether controlled or uncontrolled with antihypertensive medication, retain the ability to maintain cerebral blood flow in the face of acute changes in perfusion pressure. Pressure regulation of cerebral blood flow is unrelated to cerebrovascular reactivity to CO(2).
Collapse
Affiliation(s)
- Jorge M Serrador
- Hebrew Rehabilitation Center for Aged, Beth Israel Deaconess Medical Center Gerontology-Palmer 117, One Deaconess Road, Boston, MA 02215, USA.
| | | | | | | | | | | |
Collapse
|
92
|
Sorond FA, Ratan RR. Ironing-out mechanisms of neuronal injury under hypoxic-ischemic conditions and potential role of iron chelators as neuroprotective agents. Antioxid Redox Signal 2000; 2:421-36. [PMID: 11229356 DOI: 10.1089/15230860050192206] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Iron is the most abundant transition metal in the brain, where it functions as an important cofactor in a host of vital metabolic processes and plays an absolutely essential role in cell viability. Free iron is also very toxic when present in high concentrations, thus placing this essential metal at the core of neurotoxic injury in a number of neurological disorders. The pivotal role of iron in cellular homeostasis, including its latent toxicity, necessitates a tight regulation of iron metabolism. Oxygen and iron appear to play an important role in iron homeostasis. They appear to exert their homeostatic role by modulating the proteins involved in a complex interplay between iron sensing, transport, and storage. These key regulatory proteins include ferritin (intracellular storage), transferrin (extracellular transport), transferrin receptor, and iron regulatory protein (sensor of intracellular iron concentration). The interplay of iron and oxygen is most intriguing in the setting of stroke, where hypoxia and free iron appear to interact in causing the subsequent neuronal death.
Collapse
Affiliation(s)
- F A Sorond
- Department of Neurology, Harvard Medical School and Beth Israel-Deaconess Medical Center, Boston, MA 02115, USA.
| | | |
Collapse
|