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Li Z, Wu X, Yan Z, Cui Y, Liu Y, Cui S, Wang Y, Liu T. Unveiling the muscle-brain axis: A bidirectional mendelian randomization study investigating the causal relationship between sarcopenia-related traits and brain aging. Arch Gerontol Geriatr 2024; 123:105412. [PMID: 38513381 DOI: 10.1016/j.archger.2024.105412] [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: 01/13/2024] [Revised: 03/06/2024] [Accepted: 03/11/2024] [Indexed: 03/23/2024]
Abstract
BACKGROUND Observational studies suggest an association between sarcopenia-related traits and brain aging, but whether this association reflects a causal relationship remains unclear. This study aims to employ Mendelian randomization (MR) methods to investigate the causal impact of sarcopenia-related traits on brain aging. METHODS This study presents a comprehensive analysis of genome-wide association study (GWAS) summary data associated with sarcopenia-related traits. The data were derived from a large-scale cohort, encompassing measures such as grip strength, lean body mass, and walking pace. Measurements of brain aging were obtained from neuroimaging genetics, utilizing meta-analysis (ENIGMA) to combine magnetic resonance imaging (MRI) data from 33,992 participants. The primary methodology employed in this analysis was the inverse-variance-weighted method (IVW). Additionally, sensitivity analyses were conducted, to assess heterogeneity and pleiotropy. RESULT Appendicular lean mass(ALM) is negatively correlated with Pallidum aging; Whole body fat-free mass shows a negative correlation with Amygdala aging; Leg fat-free mass (left) and Leg fat-free mass (right) are negatively correlated with Pallidum aging; Usual walking pace is positively correlated with Nucleus Accumbens aging. Cerebellum WM aging is negatively correlated with Leg fat-free mass (left) and Leg fat-free mass (right); Hippocampus aging is negatively correlated with Hand grip strength (left) and Hand grip strength (right). Ventricles aging is positively correlated with Usual walking pace; Nucleus Accumbens aging is positively correlated with Leg fat-free mass (left) and Leg fat-free mass (right); Putamen aging is positively correlated with ALM. CONCLUSION Our study confirms that reduced muscle mass speeds up brain aging. Walking too fast raises the risk of brain aging, while maintaining or increasing appendicular lean mass, overall muscle mass, and muscle mass in both legs lowers the risk of brain aging.
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Affiliation(s)
- Zefang Li
- Department of The First Clinical medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Xueqiang Wu
- Department of Health Science, Shandong University of Traditional Chinese Medicine, Jinan, China.
| | - Zhaojun Yan
- Affiliated Hospital of Shandong University of Traditional Chinese Medicine,Jinan, China.
| | - Yiping Cui
- Department of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yueling Liu
- School of mental health and psychological science, Anhui Medical University,Hefei, China
| | - Song Cui
- Department of The First Clinical medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yining Wang
- Department of The First Clinical medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Tianyu Liu
- Department of The First Clinical medicine, Shandong University of Traditional Chinese Medicine, Jinan, China
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Miller RH, Bell EM, Russell Esposito E. Transfemoral limb loss modestly increases the metabolic cost of optimal control simulations of walking. PeerJ 2024; 12:e16756. [PMID: 38223753 PMCID: PMC10785795 DOI: 10.7717/peerj.16756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 12/13/2023] [Indexed: 01/16/2024] Open
Abstract
Background In transtibial limb loss, computer simulations suggest that the maintenance of muscle strength between pre- and post-limb loss can maintain the pre-limb loss metabolic cost. These results are consistent with comparable costs found experimentally in select cases of high functioning military service members with transtibial limb loss. It is unlikely that similar results would be found with transfemoral limb loss, although the theoretical limits are not known. Here we performed optimal control simulations of walking with and without an above-knee prosthesis to determine if transfemoral limb loss per se increases the metabolic cost of walking. Methods OpenSim Moco was used to generate optimal control simulations of walking in 15 virtual "subjects" that minimized the weighted sum of (i) deviations from average able-bodied gait mechanics and (ii) the gross metabolic cost of walking, pre-limb loss in models with two intact biological limbs, and post-limb loss with one of the limbs replaced by a prosthetic knee and foot. No other changes were made to the model. Metabolic cost was compared between pre- and post-limb loss simulations in paired t-tests. Results Metabolic cost post-limb loss increased by 0.7-9.3% (p < 0.01) depending on whether cost was scaled by total body mass or biological body mass and on whether the prosthetic knee was passive or non-passive. Conclusions Given that the post-limb loss model had numerous features that predisposed it to low metabolic cost, these results suggest transfemoral limb loss per se increases the metabolic cost of walking. However, the large differences above able-bodied peers of ∼20-45% in most gait analysis experiments may be avoidable, even when minimizing deviations from able-bodied gait mechanics. Portions of this text were previously published as part of a preprint (https://www.biorxiv.org/content/10.1101/2023.06.26.546515v2.full.pdf).
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Affiliation(s)
- Ross H. Miller
- Department of Kinesiology, University of Maryland at College Park, College Park, MD, United States of America
- Neuroscience and Cognitive Science Program, University of Maryland, College Park, MD, United States of America
| | - Elizabeth M. Bell
- Department of Kinesiology, University of Maryland at College Park, College Park, MD, United States of America
- Department of Kinesiology, Towson University, Towson, MD, United States of America
| | - Elizabeth Russell Esposito
- Military Operational Medicine Research Program, Fort Detrick, MD, United States of America
- Extremity Trauma and Amputation Center of Excellence, Fort Sam Houston, TX, United States of America
- Center for Limb Loss and Mobility, VA Puget Sound Healthcare System, Seattle, WA, United States of America
- Madigan Army Medical Center, Tacoma, WA, United States of America
- Department of Physical Medicine and Rehabilitation, Uniformed Services University of Health Sciences, Bethesda, MD, United States of America
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Dougherty RJ, Wanigatunga AA, An Y, Tian Q, Simonsick EM, Albert MS, Resnick SM, Schrack JA. Walking energetics and white matter hyperintensities in mid-to-late adulthood. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2023; 15:e12501. [PMID: 38026756 PMCID: PMC10646278 DOI: 10.1002/dad2.12501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 10/11/2023] [Accepted: 10/22/2023] [Indexed: 12/01/2023]
Abstract
INTRODUCTION White matter hyperintensities (WMHs) increase with age and contribute to cognitive and motor function decline. Energy costs for mobility worsen with age, as the energetic cost of walking increases and energetic capacity declines. We examined the cross-sectional associations of multiple measures of walking energetics with WMHs in mid- to late-aged adults. METHODS A total of 601 cognitively unimpaired adults (mean age 66.9 ± 15.3 years, 54% women) underwent brain magnetic resonance imaging scans and completed standardized slow- and peak-paced walking assessments with metabolic measurement (V̇O2). T1-weighted scans and fluid-attenuated inversion recovery images were used to quantify WMHs. Separate multivariable linear regression models examined associations adjusted for covariates. RESULTS Lower slow-paced V̇O2 (B = 0.07; P = 0.030), higher peak-paced V̇O2 (B = -0.10; P = 0.007), and lower cost-to-capacity ratio (B = .12; P < 0.0001) were all associated with lower WMH volumes. DISCUSSION The cost-to-capacity ratio, which describes the percentage of capacity required for ambulation, was the walking energetic measure most strongly associated with WMHs.
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Affiliation(s)
- Ryan J. Dougherty
- Department of NeurologyJohns Hopkins School of MedicineBaltimoreMarylandUSA
- Center on Aging and HealthJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Amal A. Wanigatunga
- Center on Aging and HealthJohns Hopkins UniversityBaltimoreMarylandUSA
- Department of EpidemiologyJohns Hopkins Bloomberg School of Public HealthBaltimoreMarylandUSA
| | - Yang An
- Intramural Research ProgramNational Institute on AgingBaltimoreMarylandUSA
| | - Qu Tian
- Intramural Research ProgramNational Institute on AgingBaltimoreMarylandUSA
| | | | - Marilyn S. Albert
- Department of NeurologyJohns Hopkins School of MedicineBaltimoreMarylandUSA
| | - Susan M. Resnick
- Intramural Research ProgramNational Institute on AgingBaltimoreMarylandUSA
| | - Jennifer A. Schrack
- Center on Aging and HealthJohns Hopkins UniversityBaltimoreMarylandUSA
- Department of EpidemiologyJohns Hopkins Bloomberg School of Public HealthBaltimoreMarylandUSA
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Kuo PL, An Y, Gross AL, Tian Q, Zipunnikov V, Spira AP, Wanigatunga AA, Simonsick EM, Ferrucci L, Resnick SM, Schrack JA. Association between walking energy utilisation and longitudinal cognitive performance in older adults. Age Ageing 2022; 51:afac240. [PMID: 36571773 PMCID: PMC9792087 DOI: 10.1093/ageing/afac240] [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: 07/08/2021] [Revised: 06/09/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Human motor function is optimised for energetic efficiency, however, age-related neurodegenerative changes affects neuromotor control of walking. Energy utilisation has been associated with motor performance, but its association with cognitive performance is unknown. METHODS The study population included 979 Baltimore Longitudinal Study of Aging participants aged $\ge$50 years (52% female, mean age: 70$\pm$10.2 years) with a median follow-up time of 4.7 years. Energy utilisation for walking was operationalised as a ratio of the energy cost of slow walking to peak walking energy expenditure during standardised tasks ('cost-ratio'). Cognitive functioning was measured using the Trail Making Tests, California Verbal Learning Test, Wechsler Adult Intelligence Scale (WAIS), letter and category fluency and card rotation tests. Linear mixed models adjusted for demographics, education and co-morbidities assessed the association between baseline cost-ratio and cognitive functioning, cross-sectionally and longitudinally. To investigate the relationship among those with less efficient energy utilisation, subgroup analyses were performed. RESULTS In fully adjusted models, a higher cost-ratio was cross-sectionally associated with poorer performance on all cognitive tests except WAIS (P < 0.05 for all). Among those with compromised energy utilisation, the baseline cost-ratio was also associated with a faster decline in memory (long-delay free recall: β = -0.4, 95% confidence interval [CI] = [-0.8, -0.02]; immediate word recall: β = -1.3, 95% CI = [-2.7, 0.1]). CONCLUSIONS These findings suggest cross-sectional and longitudinal links between energy utilisation and cognitive performance, highlighting an intriguing link between brain function and the energy needed for ambulation. Future research should examine this association earlier in the life course to gauge the potential for interventive mechanisms.
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Affiliation(s)
- Pei-Lun Kuo
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Yang An
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Alden L Gross
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Johns Hopkins Center on Aging and Health, Baltimore, MD, USA
| | - Qu Tian
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Vadim Zipunnikov
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Johns Hopkins Center on Aging and Health, Baltimore, MD, USA
| | - Adam P Spira
- Johns Hopkins Center on Aging and Health, Baltimore, MD, USA
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Department of Psychiatry & Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Amal A Wanigatunga
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Johns Hopkins Center on Aging and Health, Baltimore, MD, USA
| | - Eleanor M Simonsick
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Luigi Ferrucci
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Susan M Resnick
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Jennifer A Schrack
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Johns Hopkins Center on Aging and Health, Baltimore, MD, USA
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