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Faulkner ME, Gong Z, Bilgel M, Laporte JP, Guo A, Bae J, Palchamy E, Kaileh M, Bergeron CM, Bergeron J, Church S, D’Agostino J, Ferrucci L, Bouhrara M. Evidence of association between higher cardiorespiratory fitness and higher cerebral myelination in aging. Proc Natl Acad Sci U S A 2024; 121:e2402813121. [PMID: 39159379 PMCID: PMC11363304 DOI: 10.1073/pnas.2402813121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 07/10/2024] [Indexed: 08/21/2024] Open
Abstract
Emerging evidence suggests that altered myelination is an important pathophysiologic correlate of several neurodegenerative diseases, including Alzheimer and Parkinson's diseases. Thus, improving myelin integrity may be an effective intervention to prevent and treat age-associated neurodegenerative pathologies. It has been suggested that cardiorespiratory fitness (CRF) may preserve and enhance cerebral myelination throughout the adult lifespan, but this hypothesis has not been fully tested. Among cognitively normal participants from two well-characterized studies spanning a wide age range, we assessed CRF operationalized as the maximum rate of oxygen consumption (VO2max) and myelin content defined by myelin water fraction (MWF) estimated through our advanced multicomponent relaxometry MRI method. We found significant positive correlations between VO2max and MWF across several white matter regions. Interestingly, the effect size of this association was higher in brain regions susceptible to early degeneration, including the frontal lobes and major white matter fiber tracts. Further, the interaction between age and VO2max exhibited i) a steeper positive slope in the older age group, suggesting that the association of VO2max with MWF is stronger at middle and older ages and ii) a steeper negative slope in the lower VO2max group, indicating that lower VO2max levels are associated with lower myelination with increasing age. Finally, the nonlinear pattern of myelin maturation and decline is VO2max-dependent with the higher VO2max group reaching the MWF peak at later ages. This study provides evidence of an interconnection between CRF and cerebral myelination and suggests therapeutic strategies for promoting brain health and attenuating white matter degeneration.
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Affiliation(s)
- Mary E. Faulkner
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD21224
| | - Zhaoyuan Gong
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD21224
| | - Murat Bilgel
- Laboratory of Behavioral Neuroscience, National Institute on Aging, NIH, Baltimore, MD21224
| | - John P. Laporte
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD21224
| | - Alex Guo
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD21224
| | - Jonghyun Bae
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD21224
| | - Elango Palchamy
- Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD21224
| | - Mary Kaileh
- Clinical Research Core, National Institute on Aging, NIH, Baltimore, MD21224
| | | | - Jan Bergeron
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD21224
| | - Sarah Church
- Clinical Research Core, National Institute on Aging, NIH, Baltimore, MD21224
| | - Jarod D’Agostino
- Clinical Research Core, National Institute on Aging, NIH, Baltimore, MD21224
| | - Luigi Ferrucci
- Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD21224
| | - Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, MD21224
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Faulkner ME, Gong Z, Guo A, Laporte JP, Bae J, Bouhrara M. Harnessing myelin water fraction as an imaging biomarker of human cerebral aging, neurodegenerative diseases, and risk factors influencing myelination: A review. J Neurochem 2024. [PMID: 38973579 DOI: 10.1111/jnc.16170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 06/12/2024] [Accepted: 06/19/2024] [Indexed: 07/09/2024]
Abstract
Myelin water fraction (MWF) imaging has emerged as a promising magnetic resonance imaging (MRI) biomarker for investigating brain function and composition. This comprehensive review synthesizes the current state of knowledge on MWF as a biomarker of human cerebral aging, neurodegenerative diseases, and risk factors influencing myelination. The databases used include Web of Science, Scopus, Science Direct, and PubMed. We begin with a brief discussion of the theoretical foundations of MWF imaging, including its basis in MR physics and the mathematical modeling underlying its calculation, with an overview of the most adopted MRI methods of MWF imaging. Next, we delve into the clinical and research applications that have been explored to date, highlighting its advantages and limitations. Finally, we explore the potential of MWF to serve as a predictive biomarker for neurological disorders and identify future research directions for optimizing MWF imaging protocols and interpreting MWF in various contexts. By harnessing the power of MWF imaging, we may gain new insights into brain health and disease across the human lifespan, ultimately informing novel diagnostic and therapeutic strategies.
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Affiliation(s)
- Mary E Faulkner
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Zhaoyuan Gong
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Alex Guo
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - John P Laporte
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Jonghyun Bae
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
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Chen B, de Launoit E, Renier N, Schneeberger M. Maternal nutritional programming shapes the cerebral landscape. Trends Endocrinol Metab 2024; 35:367-370. [PMID: 37949733 DOI: 10.1016/j.tem.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2023] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 11/12/2023]
Abstract
The escalating prevalence of maternal obesity raises concerns about its influence on offspring health. Exposure to obesogenic environments during early development leads to persistent alterations in brain function contributing to neurological disorders. Nutritional programming emerges as a promising avenue to counteract the deleterious effects of maternal obesity on offspring neurodevelopment.
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Affiliation(s)
- Bandy Chen
- Laboratory of Neurovascular Control of Homeostasis, Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
| | - Elisa de Launoit
- Laboratoire de Plasticité Structurale Sorbonne Université, ICM Paris Brain Institute, INSERM U1127, CNRS UMR7225, 75013 Paris, France
| | - Nicolas Renier
- Laboratoire de Plasticité Structurale Sorbonne Université, ICM Paris Brain Institute, INSERM U1127, CNRS UMR7225, 75013 Paris, France
| | - Marc Schneeberger
- Laboratory of Neurovascular Control of Homeostasis, Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA; Wu Tsai Institute for Mind and Brain, Yale University, New Haven, CT, USA.
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Damestani NL, Jacoby J, Michel CB, Rashid B, Salat DH, Juttukonda MR. MRI Assessment of Cerebral White Matter Microvascular Hemodynamics Across the Adult Lifespan. J Magn Reson Imaging 2024:10.1002/jmri.29217. [PMID: 38179863 PMCID: PMC11224140 DOI: 10.1002/jmri.29217] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 12/18/2023] [Accepted: 12/18/2023] [Indexed: 01/06/2024] Open
Abstract
BACKGROUND Changes in cerebral hemodynamics with aging are important for understanding age-related variation in neuronal health. While many prior studies have focused on gray matter, less is known regarding white matter due in part to measurement challenges related to the lower vascular density in white matter. PURPOSE To investigate the impact of age and sex on white matter hemodynamics in a Human Connectome Project in Aging (HCP-A) cohort using tract-based spatial statistics (TBSS). STUDY TYPE Retrospective cross-sectional. POPULATION Six hundred seventy-eight typically aging individuals (381 female), aged 36-100 years. FIELD STRENGTH/SEQUENCE Multi-delay pseudo-continuous arterial spin labeling (ASL) and diffusion-weighted pulsed-gradient spin-echo echo planar imaging sequences at 3.0 T. ASSESSMENT A skeleton of mean fractional anisotropy (FA) was produced using TBSS. This skeleton was used to project ASL-derived cerebral blood flow (CBF) and arterial transit time (ATT) measures onto white matter tracts. STATISTICAL TESTS General linear models were applied to white matter FA, CBF, and ATT maps, while covarying for age and sex. Threshold-free cluster enhancement multiple comparisons correction was performed for the effects of age and sex, thresholded at PFWE < 0.05. CBF, ATT, and FA were compared between sex for each tract using analysis of covariance, with multiple comparisons correction for the number of tracts at PFDR < 0.05. RESULTS Significantly lower white matter CBF and significantly prolonged white matter ATTs were associated with older age. These effects were widespread across tracts for ATT. Significant (PFDR < 0.05) sex differences in ATT were observed across all tracts, and significant sex differences in CBF were observed in all tracts except the bilateral uncinate fasciculus. Females demonstrated significantly higher CBF compared to males across the lifespan. Few tracts demonstrated significant sex differences in FA. DATA CONCLUSION This study identified significant sex- and age-associated differences in white matter hemodynamics across tracts. EVIDENCE LEVEL 3 TECHNICAL EFFICACY: Stage 3.
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Affiliation(s)
- Nikou L. Damestani
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
| | - John Jacoby
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - Christa B. Michel
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - Barnaly Rashid
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - David H. Salat
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
- Neuroimaging Research for Veterans Center, VA Boston Healthcare System, Boston MA, USA
| | - Meher R. Juttukonda
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
- Department of Radiology, Harvard Medical School, Boston, MA, USA
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Zhang Q, Zhang Y, Shi Q, Zhao L, Yue Y, Yan C. Application study of DTI combined with ASL in the crossed cerebellar diaschisis after subacute cerebral hemorrhage. Neurol Sci 2023; 44:3949-3956. [PMID: 37335404 DOI: 10.1007/s10072-023-06908-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/08/2023] [Indexed: 06/21/2023]
Abstract
PURPOSE To study the value of 3.0T magnetic resonance imaging with diffusion tensor imaging (DTI) and 3D-arterial spin labeling (ASL) perfusion imaging in the diagnosis of the crossed cerebellar diaschisis (CCD) after the unilateral supratentorial subacute cerebral hemorrhage. METHODS Fifty-eight patients with the unilateral supratentorial subacute cerebral hemorrhage who underwent diffusion tensor imaging (DTI), 3D-arterial spin labeling (ASL), and conventional magnetic resonance imaging (MRI) scanning were enrolled. Cerebral blood flow (CBF) values of the perihematomal edema (PHE) and bilateral cerebellar hemisphere were measured on ASL mapping, and the fractional anisotropy (FA) and mean diffusivity (MD) values of the bilateral cortical, pontine, and middle cerebellar peduncle (MCP) were measured on DTI mapping. RESULTS In the CCD(+) group, FA values of the cerebral cortex and pontine ipsilateral to the lesion were statistically reduced compared to the contralateral side (P < 0.05), and the FA and MD values of the middle cerebellar peduncle (MCP) contralateral to the lesion were statistically reduced compared to the ipsilateral side (P < 0.05). Positive correlation was detected between the CBF values of the perihematomal edema (PHE) and the CBF values of cerebellar hemispheres (r = 0.642, P < 0.05), whereas the CBF values of PHE had a significantly high positive correlation with the FA in the contralateral MCP (r = 0.854, P < 0.05). CBF values in the contralateral cerebellar hemisphere correlated with FA (r = 0.466, P < 0.05) and MD values (r = 0.718, P < 0.05) in the contralateral MCP. CONCLUSION Hemodynamic alterations of PHE and cortical-ponts-cerebellum (CPC) fibrous pathway damage are associated with the development of CCD; DTI technique can assess the degree of CPC fiber pathway injury at an early stage.
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Affiliation(s)
- Qinghua Zhang
- Department of Medical Imaging, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, Shandong, China
| | - Yundu Zhang
- Department of Medical Imaging, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, Shandong, China
| | - Qiang Shi
- Department of Medical Imaging, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, Shandong, China
| | - Lei Zhao
- Department of Medical Imaging, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, Shandong, China
| | - Yun Yue
- Department of Hyperbaric Oxygen, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, Shandong, China.
| | - Chengxin Yan
- Department of Medical Imaging, The Second Affiliated Hospital of Shandong First Medical University, Taian, 271000, Shandong, China.
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Burzynska AZ, Anderson C, Arciniegas DB, Calhoun V, Choi IY, Colmenares AM, Hiner G, Kramer AF, Li K, Lee J, Lee P, Oh SH, Umland S, Thomas ML. Metabolic syndrome and adiposity: Risk factors for decreased myelin in cognitively healthy adults. CEREBRAL CIRCULATION - COGNITION AND BEHAVIOR 2023; 5:100180. [PMID: 38162292 PMCID: PMC10757180 DOI: 10.1016/j.cccb.2023.100180] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 08/11/2023] [Accepted: 08/17/2023] [Indexed: 01/03/2024]
Abstract
Metabolic syndrome (MetS) is a cluster of conditions that affects ∼25% of the global population, including excess adiposity, hyperglycemia, dyslipidemia, and elevated blood pressure. MetS is one of major risk factors not only for chronic diseases, but also for dementia and cognitive dysfunction, although the underlying mechanisms remain poorly understood. White matter is of particular interest in the context of MetS due to the metabolic vulnerability of myelin maintenance, and the accumulating evidence for the importance of the white matter in the pathophysiology of dementia. Therefore, we investigated the associations of MetS risk score and adiposity (combined body mass index and waist circumference) with myelin water fraction measured with myelin water imaging. In 90 cognitively and neurologically healthy adults (20-79 years), we found that both high MetS risk score and adiposity were correlated with lower myelin water fraction in late-myelinating prefrontal and associative fibers, controlling for age, sex, race, ethnicity, education and income. Our findings call for randomized clinical trials to establish causality between MetS, adiposity, and myelin content, and to explore the potential of weight loss and visceral adiposity reduction as means to support maintenance of myelin integrity throughout adulthood, which could open new avenues for prevention or treatment of cognitive decline and dementia.
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Affiliation(s)
- Agnieszka Z Burzynska
- The BRAiN lab, Department of Human Development and Family Studies/Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, CO, USA
| | - Charles Anderson
- Department of Computer Science, Colorado State University, Fort Collins, CO, USA
| | - David B Arciniegas
- Marcus Institute for Brain Health, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Psychiatry and Behavioral Sciences, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - Vince Calhoun
- Tri-institutional Center for Translational Research in Neuroimaging and Data Science (TReNDS), Georgia State, Georgia Tech, Emory, Atlanta, GA, USA
| | - In-Young Choi
- Department of Neurology, Department of Radiology, Hoglund Biomedical Imaging Center, University of Kansas Medical Center, Kansas City, KS, USA
| | - Andrea Mendez Colmenares
- The BRAiN lab, Department of Human Development and Family Studies/Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, CO, USA
| | - Grace Hiner
- The BRAiN lab, Department of Human Development and Family Studies/Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, CO, USA
| | - Arthur F Kramer
- Beckman Institute for Advanced Science and Technology at the University of Illinois, IL, USA
- Center for Cognitive & Brain Health, Northeastern University, Boston, MA, USA
| | - Kaigang Li
- Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Jongho Lee
- Department of Electrical and Computer Engineering, Seoul National University, Seoul, Republic of Korea
| | - Phil Lee
- Department of Radiology, Hoglund Biomedical Imaging Center, University of Kansas Medical Center, Kansas City, KS, USA
| | - Se-Hong Oh
- Division of Biomedical Engineering, Hankuk University of Foreign Studies, Gyeonggi-do, Republic of Korea
| | - Samantha Umland
- The BRAiN lab, Department of Human Development and Family Studies/Molecular, Cellular and Integrative Neurosciences, Colorado State University, Fort Collins, CO, USA
| | - Michael L Thomas
- Michael Thomas, Department of Psychology, Colorado State University, Fort Collins, CO, USA
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Laporte JP, Faulkner ME, Gong Z, Akhonda MA, Ferrucci L, Egan JM, Bouhrara M. Hypertensive Adults Exhibit Lower Myelin Content: A Multicomponent Relaxometry and Diffusion Magnetic Resonance Imaging Study. Hypertension 2023; 80:1728-1738. [PMID: 37283066 PMCID: PMC10355798 DOI: 10.1161/hypertensionaha.123.21012] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/11/2023] [Indexed: 06/08/2023]
Abstract
BACKGROUND It is unknown whether hypertension plays any role in cerebral myelination. To fill this knowledge gap, we studied 90 cognitively unimpaired adults, age range 40 to 94 years, who are participants in the Baltimore Longitudinal Study of Aging and the Genetic and Epigenetic Signatures of Translational Aging Laboratory Testing to look for potential associations between hypertension and cerebral myelin content across 14 white matter brain regions. METHODS Myelin content was probed using our advanced multicomponent magnetic resonance relaxometry method of myelin water fraction, a direct and specific magnetic resonance imaging measure of myelin content, and longitudinal and transverse relaxation rates (R1 and R2), 2 highly sensitive magnetic resonance imaging metrics of myelin content. We also applied diffusion tensor imaging magnetic resonance imaging to measure fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity values, which are metrics of cerebral microstructural tissue integrity, to provide context with previous magnetic resonance imaging findings. RESULTS After adjustment of age, sex, systolic blood pressure, smoking status, diabetes status, and cholesterol level, our results indicated that participants with hypertension exhibited lower myelin water fraction, fractional anisotropy, R1 and R2 values and higher mean diffusivity, radial diffusivity, and axial diffusivity values, indicating lower myelin content and higher impairment to the brain microstructure. These associations were significant across several white matter regions, particularly in the corpus callosum, fronto-occipital fasciculus, temporal lobes, internal capsules, and corona radiata. CONCLUSIONS These original findings suggest a direct association between myelin content and hypertension and form the basis for further investigations including longitudinal assessments of this relationship.
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Affiliation(s)
- John P. Laporte
- Laboratory of Clinical Investigation (J.P.L., M.E.F., Z.G., M.A.B.S.A., J.M.E., M.B.), National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Mary E. Faulkner
- Laboratory of Clinical Investigation (J.P.L., M.E.F., Z.G., M.A.B.S.A., J.M.E., M.B.), National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Zhaoyuan Gong
- Laboratory of Clinical Investigation (J.P.L., M.E.F., Z.G., M.A.B.S.A., J.M.E., M.B.), National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Mohammad A.B.S. Akhonda
- Laboratory of Clinical Investigation (J.P.L., M.E.F., Z.G., M.A.B.S.A., J.M.E., M.B.), National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Luigi Ferrucci
- Translational Gerontology Branch (L.F.), National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Josephine M. Egan
- Laboratory of Clinical Investigation (J.P.L., M.E.F., Z.G., M.A.B.S.A., J.M.E., M.B.), National Institute on Aging, National Institutes of Health, Baltimore, MD
| | - Mustapha Bouhrara
- Laboratory of Clinical Investigation (J.P.L., M.E.F., Z.G., M.A.B.S.A., J.M.E., M.B.), National Institute on Aging, National Institutes of Health, Baltimore, MD
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Kiely M, Triebswetter C, Gong Z, Laporte JP, Faulkner ME, Akhonda MABS, Alsameen MH, Spencer RG, Bouhrara M. Evidence of An Association Between Cerebral Blood Flow and Microstructural Integrity in Normative Aging Using a Holistic MRI Approach. J Magn Reson Imaging 2023; 58:284-293. [PMID: 36326302 PMCID: PMC10154435 DOI: 10.1002/jmri.28508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Cerebral tissue integrity decline and cerebral blood flow (CBF) alteration are major aspects of motor and cognitive dysfunctions and neurodegeneration. However, little is known about the association between blood flow and brain microstructural integrity, especially in normal aging. PURPOSE To assess the association between CBF and cerebral microstructural integrity. STUDY TYPE Cross sectional. POPULATION A total of 94 cognitively unimpaired adults (mean age 50.7 years, age range between 22 and 88 years, 56 Men). FIELD STRENGTH/SEQUENCE A 3 T; pseudo-continuous arterial spin labeling (pCASL), diffusion tensor imaging (DTI), Bayesian Monte Carlo analysis of multicomponent driven equilibrium steady-state observation of T1 and T2 (BMC-mcDESPOT). ASSESSMENT Lobar associations between CBF derived from pCASL, and longitudinal relaxation rate (R1 ), transverse relaxation rate (R2 ) and myelin water fraction (MWF) derived from BMC-mcDESPOT, or radial diffusivity (RD), axial diffusivity (AxD), mean diffusivity (MD) and fractional anisotropy (FA) derived from DTI were assessed. STATISTICAL TESTS Multiple linear regression models were used using the mean region of interest (ROI) values for MWF, R1 , R2 , FA, MD, RD, or AxD as the dependent variable and CBF, age, age2 , and sex as the independent variables. A two-sided P value of <0.05 defined statistical significance. RESULTS R1 , R2 , MWF, FA, MD, RD, and AxD parameters were associated with CBF in most of the cerebral regions evaluated. Specifically, higher CBF values were significantly associated with higher FA, MWF, R1 and R2 , or lower MD, RD and AxD values. DATA CONCLUSION These findings suggest that cerebral tissue microstructure may be impacted by global brain perfusion, adding further evidence to the intimate relationship between cerebral blood supply and cerebral tissue integrity. EVIDENCE LEVEL 4 TECHNICAL EFFICACY: Stage 4.
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Affiliation(s)
- Matthew Kiely
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, Maryland, USA
| | - Curtis Triebswetter
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, Maryland, USA
| | - Zhaoyuan Gong
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, Maryland, USA
| | - John P. Laporte
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, Maryland, USA
| | - Mary E. Faulkner
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, Maryland, USA
| | | | - Maryam H. Alsameen
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, Maryland, USA
| | - Richard G. Spencer
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, Maryland, USA
| | - Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Baltimore, Maryland, USA
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Gong Z, Bilgel M, Kiely M, Triebswetter C, Ferrucci L, Resnick SM, Spencer RG, Bouhrara M. Lower myelin content is associated with more rapid cognitive decline among cognitively unimpaired individuals. Alzheimers Dement 2023; 19:3098-3107. [PMID: 36720000 PMCID: PMC10387505 DOI: 10.1002/alz.12968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 02/01/2023]
Abstract
INTRODUCTION The influence of myelination on longitudinal changes in cognitive performance remains unclear. METHODS For each participant (N = 123), longitudinal cognitive scores were calculated. Myelin content was probed using myelin water fraction (MWF) or longitudinal relaxation rate (R1 ); both are MRI measures sensitive to myelin, with MWF being specific. RESULTS Lower MWF was associated with steeper declines in executive function (p < .02 in all regions) and lower R1 was associated with steeper declines in verbal fluency (p < .03 in all regions). Additionally, lower R1 was associated with steeper declines in executive function (p < .02 in all regions) and memory (p < .04 in occipital and cerebral white matter) but did not survive Bonferroni correction. DISCUSSION We demonstrate significant relationships between myelin content and the rates of change in cognitive performance among cognitively normal individuals. These findings highlight the importance of myelin in cognitive functioning and suggest MWF and R1 as imaging biomarkers to predict cognitive changes.
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Affiliation(s)
- Zhaoyuan Gong
- Magnetic Resonance Physics of Aging and Dementia (MRPAD) Unit, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, Maryland, USA
| | - Murat Bilgel
- Brain Aging and Behavior Section, NIA, NIH, Baltimore, Maryland, USA
| | - Matthew Kiely
- Magnetic Resonance Physics of Aging and Dementia (MRPAD) Unit, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, Maryland, USA
| | - Curtis Triebswetter
- Magnetic Resonance Physics of Aging and Dementia (MRPAD) Unit, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, Maryland, USA
| | - Luigi Ferrucci
- Longitudinal Studies Section, NIA, NIH, Baltimore, Maryland, USA
| | - Susan M Resnick
- Brain Aging and Behavior Section, NIA, NIH, Baltimore, Maryland, USA
| | - Richard G Spencer
- Magnetic Resonance Imaging and Spectroscopy Section, NIA, NIH, Baltimore, Maryland, USA
| | - Mustapha Bouhrara
- Magnetic Resonance Physics of Aging and Dementia (MRPAD) Unit, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, Maryland, USA
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Niu X, Guo Y, Chang Z, Li T, Chen Y, Zhang X, Ni H. The correlation between changes in gray matter microstructure and cerebral blood flow in Alzheimer's disease. Front Aging Neurosci 2023; 15:1205838. [PMID: 37333456 PMCID: PMC10272452 DOI: 10.3389/fnagi.2023.1205838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 05/17/2023] [Indexed: 06/20/2023] Open
Abstract
Objective To investigate the relationship between changes in cerebral blood flow (CBF) and gray matter (GM) microstructure in Alzheimer's disease (AD) and mild cognitive impairment (MCI). Methods A recruited cohort of 23 AD patients, 40 MCI patients, and 37 normal controls (NCs) underwent diffusional kurtosis imaging (DKI) for microstructure evaluation and pseudo-continuous arterial spin labeling (pCASL) for CBF assessment. We investigated the differences in diffusion- and perfusion-related parameters across the three groups, including CBF, mean diffusivity (MD), mean kurtosis (MK), and fractional anisotropy (FA). These quantitative parameters were compared using volume-based analyses for the deep GM and surface-based analyses for the cortical GM. The correlation between CBF, diffusion parameters, and cognitive scores was assessed using Spearman coefficients, respectively. The diagnostic performance of different parameters was investigated with k-nearest neighbor (KNN) analysis, using fivefold cross-validation to generate the mean accuracy (mAcc), mean precision (mPre), and mean area under the curve (mAuc). Results In the cortical GM, CBF reduction primarily occurred in the parietal and temporal lobes. Microstructural abnormalities were predominantly noted in the parietal, temporal, and frontal lobes. In the deep GM, more regions showed DKI and CBF parametric changes at the MCI stage. MD showed most of the significant abnormalities among all the DKI metrics. The MD, FA, MK, and CBF values of many GM regions were significantly correlated with cognitive scores. In the whole sample, the MD, FA, and MK were associated with CBF in most evaluated regions, with lower CBF values associated with higher MD, lower FA, or lower MK values in the left occipital lobe, left frontal lobe, and right parietal lobe. CBF values performed best (mAuc = 0.876) for distinguishing the MCI from the NC group. Last, MD values performed best (mAuc = 0.939) for distinguishing the AD from the NC group. Conclusion Gray matter microstructure and CBF are closely related in AD. Increased MD, decreased FA, and MK are accompanied by decreased blood perfusion throughout the AD course. Furthermore, CBF values are valuable for the predictive diagnosis of MCI and AD. GM microstructural changes are promising as novel neuroimaging biomarkers of AD.
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Affiliation(s)
- Xiaoxi Niu
- First Central Clinical College, Tianjin Medical University, Tianjin, China
| | - Ying Guo
- First Central Clinical College, Tianjin Medical University, Tianjin, China
| | - Zhongyu Chang
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, China
| | - Tongtong Li
- Department of Radiology, Affiliated Hospital of Hebei University, Baoding, China
| | - Yuanyuan Chen
- Tianjin International Joint Research Center for Neural Engineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
| | | | - Hongyan Ni
- Department of Radiology, Tianjin First Central Hospital, Tianjin, China
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11
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Laporte JP, Faulkner ME, Gong Z, Palchamy E, Akhonda MA, Bouhrara M. Investigation of the association between central arterial stiffness and aggregate g-ratio in cognitively unimpaired adults. Front Neurol 2023; 14:1170457. [PMID: 37181577 PMCID: PMC10167487 DOI: 10.3389/fneur.2023.1170457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 04/03/2023] [Indexed: 05/16/2023] Open
Abstract
Stiffness of the large arteries has been shown to impact cerebral white matter (WM) microstructure in both younger and older adults. However, no study has yet demonstrated an association between arterial stiffness and aggregate g-ratio, a specific magnetic resonance imaging (MRI) measure of axonal myelination that is highly correlated with neuronal signal conduction speed. In a cohort of 38 well-documented cognitively unimpaired adults spanning a wide age range, we investigated the association between central arterial stiffness, measured using pulse wave velocity (PWV), and aggregate g-ratio, measured using our recent advanced quantitative MRI methodology, in several cerebral WM structures. After adjusting for age, sex, smoking status, and systolic blood pressure, our results indicate that higher PWV values, that is, elevated arterial stiffness, were associated with lower aggregate g-ratio values, that is, lower microstructural integrity of WM. Compared to other brain regions, these associations were stronger and highly significant in the splenium of the corpus callosum and the internal capsules, which have been consistently documented as very sensitive to elevated arterial stiffness. Moreover, our detailed analysis indicates that these associations were mainly driven by differences in myelination, measured using myelin volume fraction, rather than axonal density, measured using axonal volume fraction. Our findings suggest that arterial stiffness is associated with myelin degeneration, and encourages further longitudinal studies in larger study cohorts. Controlling arterial stiffness may represent a therapeutic target in maintaining the health of WM tissue in cerebral normative aging.
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Affiliation(s)
| | | | | | | | | | - Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
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12
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Meng M, Liu F, Ma Y, Qin W, Guo L, Peng S, Gordon ML, Wang Y, Zhang N. The identification and cognitive correlation of perfusion patterns measured with arterial spin labeling MRI in Alzheimer's disease. Alzheimers Res Ther 2023; 15:75. [PMID: 37038198 PMCID: PMC10088108 DOI: 10.1186/s13195-023-01222-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 03/28/2023] [Indexed: 04/12/2023]
Abstract
BACKGROUND Vascular dysfunction, including cerebral hypoperfusion, plays an important role in the pathogenesis and progression of Alzheimer's disease (AD), independent of amyloid and tau pathology. We established an AD-related perfusion pattern (ADRP) measured with arterial spin labeling (ASL) MRI using multivariate spatial covariance analysis. METHODS We obtained multimodal MRI including pseudo-continuous ASL and neurocognitive testing in a total of 55 patients with a diagnosis of mild to moderate AD supported by amyloid PET and 46 normal controls (NCs). An ADRP was established from an identification cohort of 32 patients with AD and 32 NCs using a multivariate analysis method based on scaled subprofile model/principal component analysis, and pattern expression in individual subjects was quantified for both the identification cohort and a validation cohort (23 patients with AD and 14 NCs). Subject expression score of the ADRP was then used to assess diagnostic accuracy and cognitive correlations in AD patients and compared with global and regional cerebral blood flow (CBF) in specific areas identified from voxel-based univariate analysis. RESULTS The ADRP featured negative loading in the bilateral middle and posterior cingulate and precuneus, inferior parietal lobule, and frontal areas, and positive loading in the right cerebellum and bilateral basal areas. Subject expression score of the ADRP was significantly elevated in AD patients compared with NCs (P < 0.001) and showed good diagnostic accuracy for AD with area under receiver-operator curve of 0.87 [95% CI (0.78-0.96)] in the identification cohort and 0.85 in the validation cohort. Moreover, there were negative correlations between subject expression score and global cognitive function and performance in various cognitive domains in patients with AD. The characteristics of the ADRP topography and subject expression scores were supported by analogous findings obtained with regional CBF. CONCLUSIONS We have reported a characteristic perfusion pattern associated with AD using ASL MRI. Subject expression score of this spatial covariance pattern is a promising MRI biomarker for the identification and monitoring of AD.
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Affiliation(s)
- Meng Meng
- Department of Neurology, Tianjin Medical University General Hospital Airport Site, Tianjin, China
| | - Fang Liu
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, 154, Anshan Road, Tianjin, 300052, China
| | - Yilong Ma
- Center for Neurosciences, Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY, USA
- Department of Molecular Medicine, Donald and Barbara Zucker School of Medicine at Hofstra-Northwell, Hofstra University, Hempstead, NY, USA
| | - Wen Qin
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, China
| | - Lining Guo
- Department of Radiology and Tianjin Key Laboratory of Functional Imaging, Tianjin Medical University General Hospital, Tianjin, China
| | - Shichun Peng
- Center for Neurosciences, Institute of Molecular Medicine, The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY, USA
| | - Marc L Gordon
- The Litwin-Zucker Research Center, The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY, USA
- Departments of Neurology and Psychiatry, Donald and Barbara Zucker School of Medicine at Hofstra-Northwell, Hofstra University, Hempstead, NY, USA
| | - Yue Wang
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, 154, Anshan Road, Tianjin, 300052, China
| | - Nan Zhang
- Department of Neurology, Tianjin Medical University General Hospital Airport Site, Tianjin, China.
- Department of Neurology, Tianjin Neurological Institute, Tianjin Medical University General Hospital, 154, Anshan Road, Tianjin, 300052, China.
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13
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Fu Y, Sun Y, Wang ZB, Zhang DD, Tan L, Feng JF, Cheng W, Yu JT. Associations of Life's Simple 7 with cerebral white matter hyperintensities and microstructural integrity: UK Biobank cohort study. Eur J Neurol 2023; 30:1200-1208. [PMID: 36794682 DOI: 10.1111/ene.15750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/26/2023] [Accepted: 02/13/2023] [Indexed: 02/17/2023]
Abstract
BACKGROUND AND PURPOSE The American Heart Association Life's Simple 7 (LS7) metric was used to define optimal cardiovascular and brain health, but the associations with macrostructural hyperintensities and microstructural white matter damage are unclear. The objective was to determine the association of LS7 ideal cardiovascular health factors with macrostructural and microstructural integrity. METHOD A total of 37,140 participants with available LS7 and imaging data from UK Biobank were included in this study. Linear associations were implemented to examine the associations of LS7 score and subscores with white matter hyperintensity load (WMH) (WMH volume normalized by total white matter volume and logit-transformed) and diffusion imaging indices (fractional anisotropy [FA], mean diffusivity, orientation dispersion index [OD], intracellular volume fraction, isotropic volume fraction [ISOVF]). RESULTS In individuals (mean age 54.76 years; 19,697 females, 52.4%), higher LS7 score and subscores were strongly associated with lower WMH and microstructural white matter injury, including OD, ISOVF, FA. Both interaction analyses and stratified analyses of LS7 score and subscores with age and sex showed a strong association with microstructural damage markers, with remarkable age and sex differences. The association of OD was pronounced in females and populations younger than 50 years and FA, mean diffusivity and ISOVF were pronounced in males and populations older than 50 years. CONCLUSION These findings suggest that healthier LS7 profiles are associated with better profiles of both macrostructural and microstructural markers of brain health, and indicate that ideal cardiovascular health is associated with improved brain health.
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Affiliation(s)
- Yan Fu
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
| | - Yan Sun
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
| | - Zhi-Bo Wang
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
| | - Dan-Dan Zhang
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
| | - Lan Tan
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China
| | - Jian-Feng Feng
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China.,Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), China.,Fudan ISTBI-ZJNU Algorithm Centre for Brain-Inspired Intelligence, Zhejiang Normal University, Jinhua, China.,MOE Frontiers Center for Brain Science, Fudan University, Shanghai, China.,Zhangjiang Fudan International Innovation Center, Shanghai, China
| | - Wei Cheng
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, China.,Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), China.,Fudan ISTBI-ZJNU Algorithm Centre for Brain-Inspired Intelligence, Zhejiang Normal University, Jinhua, China.,Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, National Center for Neurological Disorders, Shanghai, China
| | - Jin-Tai Yu
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, National Center for Neurological Disorders, Shanghai, China
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14
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Yan H, Chen H, Liu Y, Zhang Q, Guo Y, Fu Y, Ren H, Wang H, Wang C, Ge Y. Assessment of cognitive impairment after acute cerebral infarction with T1 relaxation time measured by MP2RAGE sequence and cerebral hemodynamic by transcranial Doppler. Front Neurol 2022; 13:1056423. [PMID: 36561306 PMCID: PMC9763460 DOI: 10.3389/fneur.2022.1056423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/23/2022] [Indexed: 12/12/2022] Open
Abstract
Objective This study aimed to investigate early brain microstructural changes discovered using magnetization-prepared two rapid acquisition gradient echo (MP2RAGE) sequence and cerebral hemodynamic using TCD for cognitive impairment after acute cerebral infarction. Methods We enrolled 43 patients with acute cerebral infarction and 21 healthy people in the study, who were subjected to cognitive assessments, the MP2RAGE sequence, and a cerebral hemodynamic examination. A total of 26 brain regions of interest were investigated. Furthermore, we used cerebral hemodynamics to explain brain microstructural changes, which helped us better understand the pathophysiology of cognitive impairment after acute cerebral infarction and guide treatment. Results T1 relaxation times in the left frontal lobe, right frontal lobe, right temporal lobe, left precuneus, left thalamus, right hippocampus, right head of caudate nucleus, and splenium of corpus callosum were substantially different across the three groups, which were significantly correlated with neuropsychological test scores. CI group patients had significantly lower cerebral blood flow velocity than those in the N-CI and Normal groups. The receiver operating curve analysis revealed that most T1 relaxation times had high sensitivity and specificity, especially on the right temporal lobe and right frontal lobe. There was a potential correlation between T1 relaxation times and MMSE scores through TCD parameters. Conclusion The MP2RAGE sequence can detect alterations in whole brain microstructure in patients with cognitive impairment after acute cerebral infarction. Brain microstructural changes could influence cognitive function through cerebral hemodynamics. T1 relaxation times on the right temporal lobe and the right frontal lobe are expected to be a prospective biomarker of cognitive impairment after acute cerebral infarction.
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Affiliation(s)
- Hongting Yan
- The Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Honghai Chen
- The Department of Radiology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Yanzhi Liu
- The Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Qiannan Zhang
- The Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Yunchu Guo
- The Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Yu Fu
- The Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Hongling Ren
- The Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Hairong Wang
- The Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Chun Wang
- The Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Yusong Ge
- The Department of Neurology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, China
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15
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Bouhrara M, Triebswetter C, Kiely M, Bilgel M, Dolui S, Erus G, Meirelles O, Bryan NR, Detre JA, Launer LJ. Association of Cerebral Blood Flow With Longitudinal Changes in Cerebral Microstructural Integrity in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. JAMA Netw Open 2022; 5:e2231189. [PMID: 36094503 PMCID: PMC9468885 DOI: 10.1001/jamanetworkopen.2022.31189] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
IMPORTANCE Decreased cerebral tissue integrity and cerebral blood flow (CBF) are features of neurodegenerative diseases. Brain tissue maintenance is an energy-demanding process, making it particularly sensitive to hypoperfusion. However, little is known about the association between blood flow and brain microstructural integrity, including in normative aging. OBJECTIVE To assess associations between CBF and changes in cerebral tissue integrity in white matter and gray matter brain regions. DESIGN, SETTING, AND PARTICIPANTS In this longitudinal cohort study, magnetic resonance imaging was performed on 732 healthy adults from the Coronary Artery Risk Development in Young Adults (CARDIA) study, a prospective longitudinal study (baseline age of 18-30 years) that examined participants up to 8 times during 30 years (1985-1986 to 2015-2016). Cerebral blood flow was measured at baseline (year 25 of the CARDIA study), and changes in diffusion tensor indices of fractional anisotropy (FA) and mean diffusivity (MD), measures of microstructural tissue integrity, were measured at both baseline and after approximately 5 years of follow-up (year 30). Analyses were conducted from November 5, 2020, to January 29, 2022. MAIN OUTCOMES AND MEASURES Automated algorithms and linear mixed-effects statistical models were used to evaluate the associations between CBF at baseline and changes in FA or MD. RESULTS After exclusion of participants with missing or low-quality data, 654 at baseline (342 women; mean [SD] age, 50.3 [3.5] years) and 433 at follow-up (230 women; mean [SD] age, 55.1 [3.5] years) were scanned for CBF or FA and MD imaging. In the baseline cohort, 247 participants were Black (37.8%) and 394 were White (60.2%); in the follow-up cohort, 156 were Black (36.0%) and 277 were White (64.0%). Cross-sectionally, FA and MD were associated with CBF in most regions evaluated, with lower CBF values associated with lower FA or higher MD values, including the frontal white matter lobes (for CBF and MD: mean [SE] β = -1.4 [0.5] × 10-6; for CBF and FA: mean [SE] β = 2.9 [1.0] × 10-4) and the parietal white matter lobes (for CBF and MD: mean [SE] β = -2.4 [0.6] × 10-6; for CBF and FA: mean [SE] β = 4.4 [1.1] × 10-4). Lower CBF values at baseline were also significantly associated with steeper regional decreases in FA or increases in MD in most brain regions investigated, including the frontal (for CBF and MD: mean [SE] β = -1.1 [0.6] × 10-6; for CBF and FA: mean [SE] β = 2.9 [1.0] × 10-4) and parietal lobes (for CBF and MD: mean [SE] β = -1.5 [0.7] × 10-6; for CBF and FA: mean [SE] β = 4.4 [1.1] × 10-4). CONCLUSIONS AND RELEVANCE Results of this longitudinal cohort study of the association between CBF and diffusion tensor imaging metrics suggest that blood flow may be significantly associated with brain tissue microstructure. This work may lay the foundation for investigations to clarify the nature of early brain damage in neurodegeneration. Such studies may lead to new neuroimaging biomarkers of brain microstructure and function for disease progression.
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Affiliation(s)
- Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Curtis Triebswetter
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Matthew Kiely
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Murat Bilgel
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Sudipto Dolui
- Department of Radiology, University of Pennsylvania, Philadelphia
| | - Guray Erus
- Center for Biomedical Image Computing and Analytics, University of Pennsylvania, Philadelphia
| | - Osorio Meirelles
- Laboratory of Epidemiology and Population Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Nick R. Bryan
- Department of Diagnostic Medicine, University of Texas, Austin
| | - John A. Detre
- Department of Radiology, University of Pennsylvania, Philadelphia
- Department of Neurology, University of Pennsylvania, Philadelphia
| | - Lenore J. Launer
- Laboratory of Epidemiology and Population Science, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
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16
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Triebswetter C, Kiely M, Khattar N, Ferrucci L, Resnick SM, Spencer RG, Bouhrara M. Differential associations between apolipoprotein E alleles and cerebral myelin content in normative aging. Neuroimage 2022; 251:118988. [PMID: 35150834 PMCID: PMC8940662 DOI: 10.1016/j.neuroimage.2022.118988] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 01/20/2022] [Accepted: 02/08/2022] [Indexed: 11/29/2022] Open
Abstract
Mounting evidence indicates that myelin breakdown may represent an early phenomenon in neurodegeneration, including Alzheimer's disease (AD). Understanding the factors influencing myelin synthesis and breakdown will be essential for the development and evaluation of therapeutic interventions. In this work, we assessed associations between genetic variance in apolipoprotein E (APOE) and cerebral myelin content. Quantitative magnetic resonance imaging (qMRI) was performed on a cohort of 92 cognitively unimpaired adults ranging in age from 24 to 94 years. We measured whole-brain myelin water fraction (MWF), a direct measure of myelin content, as well as longitudinal and transverse relaxation rates (R1 and R2), sensitive measures of myelin content, in carriers of the APOE ε4 or APOE ε2 alleles and individuals with the ε33 genotype. Automated brain mapping algorithms and statistical models were used to evaluate the relationships between MWF or relaxation rates and APOE isoforms, accounting for confounding variables including age, sex, and race, in several cerebral structures. Our results indicate that carriers of APOE ε2 exhibited significantly higher myelin content, that is, higher MWF, R1 or R2 values, in most brain regions investigated as compared to noncarriers, while ε4 carriers exhibited trends toward lower myelin content compared to noncarriers. Finally, all qMRI metrics exhibited quadratic, inverted U-shape, associations with age; attributed to the development of myelination from young to middle age followed by progressive loss of myelin afterwards. Sex and race effects on myelination were, overall, nonsignificant. These findings suggest that individual genetic background may influence cerebral myelin maintenance. Although preliminary, this work lays the foundation for further investigations to clarify the relationship between APOE genotype and myelination, which may suggest potential targets in treatment or prevention of AD.
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Affiliation(s)
- Curtis Triebswetter
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, BRC 05C-222, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Matthew Kiely
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, BRC 05C-222, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Nikkita Khattar
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, BRC 05C-222, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Luigi Ferrucci
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Susan M Resnick
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Richard G Spencer
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, BRC 05C-222, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Mustapha Bouhrara
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, BRC 05C-222, 251 Bayview Blvd., Baltimore, MD 21224, USA.
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17
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Wang Y, Lu P, Zhan Y, Wu X, Qiu Y, Wang Z, Xu Q, Zhou Y. The Contribution of White Matter Diffusion and Cortical Perfusion Pathology to Vascular Cognitive Impairment: A Multimode Imaging-Based Machine Learning Study. Front Aging Neurosci 2021; 13:687001. [PMID: 34426730 PMCID: PMC8379092 DOI: 10.3389/fnagi.2021.687001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 07/02/2021] [Indexed: 11/13/2022] Open
Abstract
Widespread impairments in white matter and cerebrovascular integrity have been consistently implicated in the pathophysiology of patients with small vessel disease (SVD). However, the neural circuit mechanisms that underlie the developing progress of clinical cognitive symptoms remain largely elusive. Here, we conducted cross-modal MRI scanning including diffusion tensor imaging and arterial spin labeling in a cohort of 113 patients with SVD, which included 74 patients with vascular mild cognitive impairment (vMCI) and 39 patients without vMCI symptoms, and hence developed multimode imaging-based machine learning models to identify markers that discriminated SVD subtypes. Diffusion and perfusion features, respectively, extracted from individual white matter and gray matter regions were used to train three sets of classifiers in a nested 10-fold fashion: diffusion-based, perfusion-based, and combined diffusion-perfusion-based classifiers. We found that the diffusion-perfusion combined classifier achieved the highest accuracy of 72.57% with leave-one-out cross-validation, with the diffusion features largely spanning the capsular lateral pathway of the cholinergic tracts, and the perfusion features mainly distributed in the frontal-subcortical-limbic areas. Furthermore, diffusion-based features within vMCI group were associated with performance on executive function tests. We demonstrated the superior accuracy of using diffusion-perfusion combined multimode imaging features for classifying vMCI subtype out of a cohort of patients with SVD. Disruption of white matter integrity might play a critical role in the progression of cognitive impairment in patients with SVD, while malregulation of coritcal perfusion needs further study.
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Affiliation(s)
- Yao Wang
- Department of Radiology, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Peiwen Lu
- Department of Neurology, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yafeng Zhan
- Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, China
| | - Xiaowei Wu
- Department of Radiology, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yage Qiu
- Department of Radiology, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Zheng Wang
- Center for Excellence in Brain Science and Intelligence Technology, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, China
| | - Qun Xu
- Department of Neurology, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yan Zhou
- Department of Radiology, RenJi Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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18
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Sisco NJ, Borazanci A, Dortch R, Stokes AM. Investigating the relationship between multi-scale perfusion and white matter microstructural integrity in patients with relapsing-remitting MS. Mult Scler J Exp Transl Clin 2021; 7:20552173211037002. [PMID: 34377529 PMCID: PMC8330486 DOI: 10.1177/20552173211037002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 07/16/2021] [Indexed: 11/20/2022] Open
Abstract
Background Multiple sclerosis is characterized by the formation of central nervous system demyelinating lesions with microvasculature inflammation. Objective Evaluate how lesion cerebral perfusion relates to white matter microstructural integrity in patients with RRMS using perfusion MRI and myelin-related T1-weighted to T2-weighted (T1w/T2w) ratios. Methods Forty-eight patients with RRMS were imaged with dynamic susceptibility contrast imaging using SAGE (spin- and gradient-echo) to calculate global and capillary-sized perfusion parameters, including cerebral blood flow (CBF), volume (CBV), and mean transit time (MTT). T1w/T2w ratios were used to indirectly assess white matter microstructural integrity. Results For global perfusion metrics, CBF was reduced 28.4% in lesion regions of interest (ROIs) compared to normal appearing white matter (NAWM), CBV was reduced 25.9% in lesion ROIs compared to NAWM, and MTT increased 12.9%. For capillary perfusion metrics (via spin-echo (SE)), CBF-SE was reduced 35.7% in lesion ROIs compared to NAWM, CBV-SE was reduced 35.2% in lesion ROIs compared to NAWM, and MTT-SE increased 9.1%. Capillary-level CBF was correlated (ρ = 0.34, p = 0.024) with white matter microstructural integrity in lesion ROIs. Conclusion This study demonstrates that lesion perfusion is reduced at both the global and capillary level and capillary-associated hypoperfusion is associated with reduced white matter microstructural integrity in RRMS.
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Affiliation(s)
- Nicholas J Sisco
- Division of Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Aimee Borazanci
- Division of Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Richard Dortch
- Division of Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Ashley M Stokes
- Division of Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, USA
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19
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Khattar N, Triebswetter C, Kiely M, Ferrucci L, Resnick SM, Spencer RG, Bouhrara M. Investigation of the association between cerebral iron content and myelin content in normative aging using quantitative magnetic resonance neuroimaging. Neuroimage 2021; 239:118267. [PMID: 34139358 PMCID: PMC8370037 DOI: 10.1016/j.neuroimage.2021.118267] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 12/24/2022] Open
Abstract
Myelin loss and iron accumulation are cardinal features of aging and various neurodegenerative diseases. Oligodendrocytes incorporate iron as a metabolic substrate for myelin synthesis and maintenance. An emerging hypothesis in Alzheimer’s disease research suggests that myelin breakdown releases substantial stores of iron that may accumulate, leading to further myelin breakdown and neurodegeneration. We assessed associations between iron content and myelin content in critical brain regions using quantitative magnetic resonance imaging (MRI) on a cohort of cognitively unimpaired adults ranging in age from 21 to 94 years. We measured whole-brain myelin water fraction (MWF), a surrogate of myelin content, using multicomponent relaxometry, and whole-brain iron content using susceptibility weighted imaging in all individuals. MWF was negatively associated with iron content in most brain regions evaluated indicating that lower myelin content corresponds to higher iron content. Moreover, iron content was significantly higher with advanced age in most structures, with men exhibiting a trend towards higher iron content as compared to women. Finally, relationship between MWF and age, in all brain regions investigated, suggests that brain myelination continues until middle age, followed by degeneration at older ages. This work establishes a foundation for further investigations of the etiology and sequelae of myelin breakdown and iron accumulation in neurodegeneration and may lead to new imaging markers for disease progression and treatment.
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Affiliation(s)
- Nikkita Khattar
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Curtis Triebswetter
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Matthew Kiely
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Luigi Ferrucci
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Susan M Resnick
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Richard G Spencer
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States
| | - Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, 21224 MD, United States.
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20
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Bouhrara M, Cortina LE, Khattar N, Rejimon AC, Ajamu S, Cezayirli DS, Spencer RG. Maturation and degeneration of the human brainstem across the adult lifespan. Aging (Albany NY) 2021; 13:14862-14891. [PMID: 34115614 PMCID: PMC8221341 DOI: 10.18632/aging.203183] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/20/2021] [Indexed: 04/12/2023]
Abstract
Brainstem tissue microstructural properties change across the adult lifespan. However, studies elucidating the biological processes that govern brainstem maturation and degeneration in-vivo are lacking. In the present work, conducted on a large cohort of 140 cognitively unimpaired subjects spanning a wide age range of 21 to 94 years, we implemented a multi-parameter approach to characterize the sex- and age differences. In addition, we examined regional correlations between myelin water fraction (MWF), a direct measure of myelin content, and diffusion tensor imaging indices, and transverse and longitudinal relaxation rates to evaluate whether these metrics provide information complementary to MWF. We observed region-dependent differences in myelin content and axonal density with age and found that both exhibit an inverted U-shape association with age in several brainstem substructures. We emphasize that the microstructural differences captured by our distinct MRI metrics, along with their weak associations with MWF, strongly indicate the potential of using these outcome measures in a multi-parametric approach. Furthermore, our results support the gain-predicts-loss hypothesis of tissue maturation and degeneration in the brainstem. Indeed, our results indicate that myelination follows a temporally symmetric time course across the adult life span, while axons appear to degenerate significantly more rapidly than they mature.
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Affiliation(s)
- Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Luis E. Cortina
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Nikkita Khattar
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Abinand C. Rejimon
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Samuel Ajamu
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Defne S. Cezayirli
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Richard G. Spencer
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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21
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Bouhrara M, Khattar N, Elango P, Resnick SM, Ferrucci L, Spencer RG. Evidence of association between obesity and lower cerebral myelin content in cognitively unimpaired adults. Int J Obes (Lond) 2021; 45:850-859. [PMID: 33483582 PMCID: PMC8009848 DOI: 10.1038/s41366-021-00749-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 12/16/2020] [Accepted: 01/07/2021] [Indexed: 01/30/2023]
Abstract
BACKGROUND Myelin loss is a central feature of several neurodegenerative diseases, including Alzheimer's disease (AD). In animal studies, a link has been established between obesity and impairment of oligodendrocyte maturation, the cells that produce and maintain myelin. Although clinical magnetic resonance imaging (MRI) studies have revealed microstructural alterations of cerebral white matter tissue in subjects with obesity, no specific myelin vs. obesity correlation studies have been performed in humans using a direct myelin content metric. OBJECTIVES To assess the association between obesity and myelin integrity in cerebral white matter using advanced MRI methodology for myelin content imaging. METHODS Studies were performed in the clinical unit of the National Institute on Aging on a cohort of 119 cognitively unimpaired adults. Using advanced MRI methodology, we measured whole-brain myelin water fraction (MWF), a marker of myelin content. Automated brain mapping algorithms and statistical models were used to evaluate the relationships between MWF and obesity, measured using the body mass index (BMI) or waist circumference (WC), in various white matter brain regions. RESULTS MWF was negatively associated with BMI or WC in all brain regions evaluated. These associations, adjusted for sex, ethnicity, and age, were statistically significant in most brain regions examined (p < 0.05), with higher BMI or WC corresponding to lower myelin content. Finally, in agreement with previous work, MWF exhibited a quadratic, inverted U-shaped, association with age; this is attributed to the process of myelination from youth through middle age, followed by demyelination afterward. CONCLUSIONS These findings suggest that obesity was significantly associated with white matter integrity, and in particular myelin content. We expect that this work will lay the foundation for further investigations to clarify the nature of myelin damage in neurodegeneration, including AD, and the effect of lifestyle factors such as diet and physical activity on myelination.
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Affiliation(s)
- Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute
on Aging, National Institutes of Health, Baltimore, 21224 MD, USA.,†Corresponding author: Mustapha
Bouhrara, PhD., National Institutes of Health (NIH), National
Institute on Aging (NIA), Intramural Research Program, BRC 04B-117, 251 Bayview
Boulevard, Baltimore, MD 21224, USA. Tel: 410-558-8541,
| | - Nikkita Khattar
- Laboratory of Clinical Investigation, National Institute
on Aging, National Institutes of Health, Baltimore, 21224 MD, USA
| | - Palchamy Elango
- Translational Gerontology Branch, National Institute on
Aging, National Institutes of Health, Baltimore, 21224 MD, USA
| | - Susan M. Resnick
- Laboratory of Behavioral Neuroscience, National Institute
on Aging, National Institutes of Health, Baltimore, 21224 MD, USA
| | - Luigi Ferrucci
- Translational Gerontology Branch, National Institute on
Aging, National Institutes of Health, Baltimore, 21224 MD, USA
| | - Richard G. Spencer
- Laboratory of Clinical Investigation, National Institute
on Aging, National Institutes of Health, Baltimore, 21224 MD, USA
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22
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Daugherty AM. Hypertension-related risk for dementia: A summary review with future directions. Semin Cell Dev Biol 2021; 116:82-89. [PMID: 33722505 DOI: 10.1016/j.semcdb.2021.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/01/2021] [Accepted: 03/06/2021] [Indexed: 02/07/2023]
Abstract
Chronic hypertension, or high blood pressure, is the most prevalent vascular risk factor that accelerates cognitive aging and increases risk for Alzheimer's disease and related dementia. Decades of observational and clinical trials have demonstrated that midlife hypertension is associated with greater gray matter atrophy, white matter damage commiserate with demyelination, and functional deficits as compared to normotension over the adult lifespan. Critically, hypertension is a modifiable dementia risk factor: successful blood pressure control with antihypertensive treatment improves outcomes as compared to uncontrolled hypertension, but does not completely negate the risk for dementia. This suggests that hypertension-related risk for neural and cognitive decline in aging cannot be due to elevations in blood pressure alone. This summary review describes three putative pathways for hypertension-related dementia risk: oxidative damage and metabolic dysfunction; systemic inflammation; and autonomic control of heart rate variability. The same processes contribute to pre-clinical hypertension, and therefore hypertension may be an early symptom of an aging nervous system that then exacerbates cumulative and progressive neurodegeneration. Current evidence is reviewed and future directions for research are outlined, including blood biomarkers and novel neuroimaging methods that may be sensitive to test the specific hypotheses.
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Affiliation(s)
- Ana M Daugherty
- Department of Psychology, Department of Psychiatry and Behavioral Neurosciences, Institute of Gerontology, Wayne State University, 5057 Woodward Ave., Detroit, MI, USA.
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23
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Alisch JSR, Khattar N, Kim RW, Cortina LE, Rejimon AC, Qian W, Ferrucci L, Resnick SM, Spencer RG, Bouhrara M. Sex and age-related differences in cerebral blood flow investigated using pseudo-continuous arterial spin labeling magnetic resonance imaging. Aging (Albany NY) 2021; 13:4911-4925. [PMID: 33596183 PMCID: PMC7950235 DOI: 10.18632/aging.202673] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/01/2021] [Indexed: 02/07/2023]
Abstract
Adequate cerebral blood flow (CBF) is essential to a healthy central nervous system (CNS). Previous work suggests that CBF differs between men and women, and declines with age and certain pathologies, but a highly controlled systematic study across a wide age range, and incorporating white matter (WM) regions, has not been undertaken. Here, we investigate age- and sex-related differences in CBF in gray matter (GM) and WM regions in a cohort (N = 80) of cognitively unimpaired individuals over a wide age range. In agreement with literature, we find that GM regions exhibited lower CBF with age. In contrast, WM regions exhibited higher CBF with age in various cerebral regions. We attribute this new finding to increased oligodendrocyte metabolism to maintain myelin homeostasis in the setting of increased myelin turnover with age. Further, consistent with prior studies, we found that CBF was higher in women than in men in all brain structures investigated. Our work provides new insights into the effects of age and sex on CBF. In addition, our results provide reference CBF values for the standard ASL protocol recommended by the ISMRM Perfusion Study Group and the European ASL in Dementia consortium. Thus, these results provide a foundation for further investigations of CNS perfusion in a variety of settings, including aging, cerebrovascular diseases, and dementias.
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Affiliation(s)
- Joseph S R Alisch
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 20892, USA
| | - Nikkita Khattar
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 20892, USA
| | - Richard W Kim
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 20892, USA
| | - Luis E Cortina
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 20892, USA
| | - Abinand C Rejimon
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 20892, USA
| | - Wenshu Qian
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 20892, USA
| | - Luigi Ferrucci
- Laboratory Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 20892, USA
| | - Susan M Resnick
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD 20892, USA
| | - Richard G Spencer
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 20892, USA
| | - Mustapha Bouhrara
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD 20892, USA
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24
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Qian W, Khattar N, Cortina LE, Spencer RG, Bouhrara M. Nonlinear associations of neurite density and myelin content with age revealed using multicomponent diffusion and relaxometry magnetic resonance imaging. Neuroimage 2020; 223:117369. [PMID: 32931942 PMCID: PMC7775614 DOI: 10.1016/j.neuroimage.2020.117369] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 12/18/2022] Open
Abstract
Most magnetic resonance imaging (MRI) studies investigating the relationship between regional brain myelination or axonal density and aging have relied upon nonspecific methods to probe myelin and axonal content, including diffusion tensor imaging and relaxation time mapping. While these studies have provided pivotal insights into changes in cerebral architecture with aging and pathology, details of the underlying microstructural alterations have not been fully elucidated. In the current study, we used the BMC-mcDESPOT analysis, a direct and specific multicomponent relaxometry method for imaging of myelin water fraction (MWF), a marker of myelin content, and NODDI, an emerging multicomponent diffusion technique, for neurite density index (NDI) imaging, a proxy of axonal density. We investigated age-related differences in MWF and NDI in several white matter brain regions in a cohort of cognitively unimpaired participants over a wide age range. Our results indicate a quadratic, inverted U-shape, relationship between MWF and age in all brain regions investigated, suggesting that myelination continues until middle age followed by a decrease at older ages, in agreement with previous work. We found a similarly complex regional association between NDI and age, with several cerebral structures also exhibiting a quadratic, inverted U-shape, relationship. This novel observation suggests an increase in axonal density until the fourth decade of age followed by a rapid loss at older ages. We also observed that these age-related differences in MWF and NDI vary across different brain regions, as expected. Finally, our study indicates no significant association between MWF and NDI in most cerebral structures investigated, although this association approached significance in a limited number of brain regions, indicating the complementary nature of their information and encouraging further investigation. Overall, we find evidence of nonlinear associations between age and myelin or axonal density in a sample of well-characterized adults, using direct myelin and axonal content imaging methods.
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Affiliation(s)
- Wenshu Qian
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigations, National Institute on Aging, National Institutes of Health, NIA, NIH, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Nikkita Khattar
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigations, National Institute on Aging, National Institutes of Health, NIA, NIH, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Luis E Cortina
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigations, National Institute on Aging, National Institutes of Health, NIA, NIH, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Richard G Spencer
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigations, National Institute on Aging, National Institutes of Health, NIA, NIH, 251 Bayview Blvd., Baltimore, MD 21224, USA
| | - Mustapha Bouhrara
- Magnetic Resonance Physics of Aging and Dementia Unit, Laboratory of Clinical Investigations, National Institute on Aging, National Institutes of Health, NIA, NIH, 251 Bayview Blvd., Baltimore, MD 21224, USA.
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