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1.
Cereb Cortex ; 34(5)2024 May 02.
Article in English | MEDLINE | ID: mdl-38741269

ABSTRACT

The basal nuclei are important during infancy because of the significant development of motor skills. The main aim of this study was to evaluate the shape differences of the lentiform nucleus between different age and gender groups. A total of 126 children's axial magnetic resonance image series were included in the presented study. These images were grouped between 1 and 5 yr old. Right and left lentiform nuclei are marked with selected landmarks using TPSDIG v2.04. Statistical shape analyses were examined by a Generalized Procrustes Analysis. Our results showed that there was no statistically significant difference in lentiform nucleus shape between genders. However, there was a difference between the shapes of the right and left lentiform nuclei between the 1-yr and 5-yr age groups. These results demonstrated the shape changes in the lentiform nucleus during the first 5 yr of life. Further clinical studies based on our results may be used to gather more detailed information about movement disorders and neuronal development.


Subject(s)
Magnetic Resonance Imaging , Humans , Male , Female , Child, Preschool , Infant , Magnetic Resonance Imaging/methods , Retrospective Studies , Aging/physiology , Aging/pathology , Basal Ganglia/diagnostic imaging
2.
Front Endocrinol (Lausanne) ; 15: 1361289, 2024.
Article in English | MEDLINE | ID: mdl-38694941

ABSTRACT

Mitochondria plays an essential role in regulating cellular metabolic homeostasis, proliferation/differentiation, and cell death. Mitochondrial dysfunction is implicated in many age-related pathologies. Evidence supports that the dysfunction of mitochondria and the decline of mitochondrial DNA copy number negatively affect ovarian aging. However, the mechanism of ovarian aging is still unclear. Treatment methods, including antioxidant applications, mitochondrial transplantation, emerging biomaterials, and advanced technologies, are being used to improve mitochondrial function and restore oocyte quality. This article reviews key evidence and research updates on mitochondrial damage in the pathogenesis of ovarian aging, emphasizing that mitochondrial damage may accelerate and lead to cellular senescence and ovarian aging, as well as exploring potential methods for using mitochondrial mechanisms to slow down aging and improve oocyte quality.


Subject(s)
Aging , Mitochondria , Ovary , Humans , Mitochondria/metabolism , Female , Aging/physiology , Aging/pathology , Ovary/metabolism , Ovary/pathology , Animals , Cellular Senescence , DNA, Mitochondrial/metabolism , DNA, Mitochondrial/genetics , Oocytes/metabolism
3.
Acta Neuropathol ; 147(1): 82, 2024 May 09.
Article in English | MEDLINE | ID: mdl-38722375

ABSTRACT

Aging affects all cell types in the CNS and plays an important role in CNS diseases. However, the underlying molecular mechanisms driving these age-associated changes and their contribution to diseases are only poorly understood. The white matter in the aging brain as well as in diseases, such as Multiple sclerosis is characterized by subtle abnormalities in myelin sheaths and paranodes, suggesting that oligodendrocytes, the myelin-maintaining cells of the CNS, lose the capacity to preserve a proper myelin structure and potentially function in age and certain diseases. Here, we made use of directly converted oligodendrocytes (dchiOL) from young, adult and old human donors to study age-associated changes. dchiOL from all three age groups differentiated in an comparable manner into O4 + immature oligodendrocytes, but the proportion of MBP + mature dchiOL decreased with increasing donor age. This was associated with an increased ROS production and upregulation of cellular senescence markers such as CDKN1A, CDKN2A in old dchiOL. Comparison of the transcriptomic profiles of dchiOL from adult and old donors revealed 1324 differentially regulated genes with limited overlap with transcriptomic profiles of the donors' fibroblasts or published data sets from directly converted human neurons or primary rodent oligodendroglial lineage cells. Methylome analyses of dchiOL and human white matter tissue samples demonstrate that chronological and epigenetic age correlate in CNS white matter as well as in dchiOL and resulted in the identification of an age-specific epigenetic signature. Furthermore, we observed an accelerated epigenetic aging of the myelinated, normal appearing white matter of multiple sclerosis (MS) patients compared to healthy individuals. Impaired differentiation and upregulation of cellular senescence markers could be induced in young dchiOL in vitro using supernatants from pro-inflammatory microglia. In summary, our data suggest that physiological aging as well as inflammation-induced cellular senescence contribute to oligodendroglial pathology in inflammatory demyelinating diseases such as MS.


Subject(s)
Aging , Cellular Senescence , Multiple Sclerosis , Oligodendroglia , Humans , Oligodendroglia/pathology , Oligodendroglia/metabolism , Cellular Senescence/physiology , Aging/pathology , Multiple Sclerosis/pathology , Multiple Sclerosis/metabolism , Adult , Aged , Middle Aged , Male , Female , Young Adult , Inflammation/pathology , Inflammation/metabolism , White Matter/pathology , Cyclin-Dependent Kinase Inhibitor p16/metabolism , Cyclin-Dependent Kinase Inhibitor p21
4.
eNeuro ; 11(5)2024 May.
Article in English | MEDLINE | ID: mdl-38719452

ABSTRACT

The corpus callosum is composed of several subregions, distinct in cellular and functional organization. This organization scheme may render these subregions differentially vulnerable to the aging process. Callosal integrity may be further compromised by cardiovascular risk factors, which negatively influence white matter health. Here, we test for heterochronicity of aging, hypothesizing an anteroposterior gradient of vulnerability to aging that may be altered by the effects of cardiovascular health. In 174 healthy adults across the adult lifespan (mean age = 53.56 ± 18.90; range, 20-94 years old, 58.62% women), pulse pressure (calculated as participant's systolic minus diastolic blood pressure) was assessed to determine cardiovascular risk. A deterministic tractography approach via diffusion-weighted imaging was utilized to extract fractional anisotropy (FA), radial diffusivity (RD), and axial diffusivity (AD) from each of five callosal subregions, serving as estimates of microstructural health. General linear models tested the effects of age, hypertension, and pulse pressure on these cross-sectional metrics. We observed no significant effect of hypertensive diagnosis on callosal microstructure. We found a significant main effect of age and an age-pulse pressure interaction whereby older age and elevated pulse pressure were associated with poorer FA, AD, and RD. Age effects revealed nonlinear components and occurred along an anteroposterior gradient of severity in the callosum. This gradient disappeared when pulse pressure was considered. These results indicate that age-related deterioration across the callosum is regionally variable and that pulse pressure, a proxy of arterial stiffness, exacerbates this aging pattern in a large lifespan cohort.


Subject(s)
Aging , Blood Pressure , Corpus Callosum , Humans , Corpus Callosum/diagnostic imaging , Corpus Callosum/physiology , Female , Middle Aged , Aged , Adult , Male , Aging/physiology , Aging/pathology , Aged, 80 and over , Young Adult , Blood Pressure/physiology , Diffusion Tensor Imaging , Hypertension/physiopathology , Hypertension/pathology , Cross-Sectional Studies , Diffusion Magnetic Resonance Imaging
6.
Behav Brain Funct ; 20(1): 10, 2024 May 03.
Article in English | MEDLINE | ID: mdl-38702688

ABSTRACT

BACKGROUND: Episodic memory (EM) deteriorates as a result of normal aging as well as Alzheimer's disease. The neural underpinnings of such age-related memory impairments in older individuals are not well-understood. Although previous research has unveiled the association between gray matter volume (GMV) and EM in the elderly population, such findings exhibit variances across distinct age cohorts. Consequently, an investigation into the dynamic evolution of this relationship with advancing age is imperative. RESULT: The present study utilized a sliding window approach to examine how the correlation between EM and GMV varied with age in a cross-sectional sample of 926 Chinese older adults. We found that both verbal EM (VEM) and spatial EM (SEM) exhibited positive correlations with GMV in extensive areas primarily in the temporal and frontal lobes and that these correlations typically became stronger with older age. Moreover, there were variations in the strength of the correlation between EM and GMV with age, which differed based on sex and the specific type of EM. Specifically, the association between VEM and GMVs in the insula and parietal regions became stronger with age for females but not for males, whereas the association between SEM and GMVs in the parietal and occipital regions became stronger for males but not for females. At the brain system level, there is a significant age-related increase in the correlations between both types of EM and the GMV of both the anterior temporal (AT) system and the posterior medial (PM) system in male group. In females, both types of EM show stronger age-related correlations with the GMV of the AT system compared to males. CONCLUSIONS: Our study revealed a significant positive correlation between GMV in most regions associated with EM and age, particularly in the frontal and temporal lobes. This discovery offers new insights into the connection between brain structure and the diminishing episodic memory function among older individuals.


Subject(s)
Aging , Frontal Lobe , Gray Matter , Magnetic Resonance Imaging , Memory, Episodic , Temporal Lobe , Humans , Male , Female , Aged , Gray Matter/diagnostic imaging , Frontal Lobe/diagnostic imaging , Aging/physiology , Aging/pathology , Temporal Lobe/diagnostic imaging , Middle Aged , Magnetic Resonance Imaging/methods , Cross-Sectional Studies , Aged, 80 and over , Organ Size/physiology
7.
Neurobiol Dis ; 196: 106523, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38705491

ABSTRACT

Down syndrome (DS) is the most common condition with intellectual disability and is caused by trisomy of Homo sapiens chromosome 21 (HSA21). The increased dosage of genes on HSA21 is associated with early neurodevelopmental changes and subsequently at adult age with the development of Alzheimer-like cognitive decline. However, the molecular mechanisms promoting brain pathology along aging are still missing. The novel Ts66Yah model represents an evolution of the Ts65Dn, used in characterizing the progression of brain degeneration, and it manifest phenotypes closer to human DS condition. In this study we performed a longitudinal analysis (3-9 months) of adult Ts66Yah mice. Our data support the behavioural alterations occurring in Ts66Yah mice at older age with improvement in the detection of spatial memory defects and also a new anxiety-related phenotype. The evaluation of hippocampal molecular pathways in Ts66Yah mice, as effect of age, demonstrate the aberrant regulation of redox balance, proteostasis, stress response, metabolic pathways, programmed cell death and synaptic plasticity. Intriguingly, the genotype-driven changes observed in those pathways occur early promoting altered brain development and the onset of a condition of premature aging. In turn, aging may account for the subsequent hippocampal deterioration that fall in characteristic neuropathological features. Besides, the analysis of sex influence in the alteration of hippocampal mechanisms demonstrate only a mild effect. Overall, data collected in Ts66Yah provide novel and consolidated insights, concerning trisomy-driven processes that contribute to brain pathology in conjunction with aging. This, in turn, aids in bridging the existing gap in comprehending the intricate nature of DS phenotypes.


Subject(s)
Aging , Brain , Disease Models, Animal , Down Syndrome , Animals , Down Syndrome/genetics , Down Syndrome/pathology , Down Syndrome/metabolism , Aging/genetics , Aging/pathology , Aging/physiology , Mice , Male , Brain/metabolism , Brain/pathology , Female , Cognition/physiology , Hippocampus/metabolism , Hippocampus/pathology , Cognitive Dysfunction/genetics , Cognitive Dysfunction/metabolism , Cognitive Dysfunction/pathology , Mice, Transgenic
8.
Cells ; 13(9)2024 Apr 25.
Article in English | MEDLINE | ID: mdl-38727285

ABSTRACT

With the increasing proportion of the aging population, neurodegenerative diseases have become one of the major health issues in society. Neurodegenerative diseases (NDs), including multiple sclerosis (MS), Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), are characterized by progressive neurodegeneration associated with aging, leading to a gradual decline in cognitive, emotional, and motor functions in patients. The process of aging is a normal physiological process in human life and is accompanied by the aging of the immune system, which is known as immunosenescence. T-cells are an important part of the immune system, and their senescence is the main feature of immunosenescence. The appearance of senescent T-cells has been shown to potentially lead to chronic inflammation and tissue damage, with some studies indicating a direct link between T-cell senescence, inflammation, and neuronal damage. The role of these subsets with different functions in NDs is still under debate. A growing body of evidence suggests that in people with a ND, there is a prevalence of CD4+ T-cell subsets exhibiting characteristics that are linked to senescence. This underscores the significance of CD4+ T-cells in NDs. In this review, we summarize the classification and function of CD4+ T-cell subpopulations, the characteristics of CD4+ T-cell senescence, the potential roles of these cells in animal models and human studies of NDs, and therapeutic strategies targeting CD4+ T-cell senescence.


Subject(s)
CD4-Positive T-Lymphocytes , Cellular Senescence , Neurodegenerative Diseases , Humans , Neurodegenerative Diseases/immunology , Neurodegenerative Diseases/pathology , Neurodegenerative Diseases/therapy , CD4-Positive T-Lymphocytes/immunology , Cellular Senescence/immunology , Animals , Aging/immunology , Aging/pathology , T-Cell Senescence
9.
Cells ; 13(9)2024 Apr 30.
Article in English | MEDLINE | ID: mdl-38727299

ABSTRACT

The adipose organ adapts and responds to internal and environmental stimuli by remodeling both its cellular and extracellular components. Under conditions of energy surplus, the subcutaneous white adipose tissue (WAT) is capable of expanding through the enlargement of existing adipocytes (hypertrophy), followed by de novo adipogenesis (hyperplasia), which is impaired in hypertrophic obesity. However, an impaired hyperplastic response may result from various defects in adipogenesis, leading to different WAT features and metabolic consequences, as discussed here by reviewing the results of the studies in animal models with either overexpression or knockdown of the main molecular regulators of the two steps of the adipogenesis process. Moreover, impaired WAT remodeling with aging has been associated with various age-related conditions and reduced lifespan expectancy. Here, we delve into the latest advancements in comprehending the molecular and cellular processes underlying age-related changes in WAT function, their involvement in common aging pathologies, and their potential as therapeutic targets to influence both the health of elderly people and longevity. Overall, this review aims to encourage research on the mechanisms of WAT maladaptation common to conditions of both excessive and insufficient fat tissue. The goal is to devise adipocyte-targeted therapies that are effective against both obesity- and age-related disorders.


Subject(s)
Adipogenesis , Adipose Tissue, White , Aging , Obesity , Humans , Aging/pathology , Obesity/pathology , Obesity/metabolism , Adipose Tissue, White/metabolism , Adipose Tissue, White/pathology , Animals , Adipocytes/metabolism , Adipocytes/pathology
10.
PLoS One ; 19(4): e0299670, 2024.
Article in English | MEDLINE | ID: mdl-38626149

ABSTRACT

BACKGROUND: Myelin and iron are major contributors to the cortical MR signal. The aim of this study was to investigate 1. Can MP2RAGE-derived contrasts at 7T in combination with k-means clustering be used to distinguish between heavily and sparsely myelinated layers in cortical gray matter (GM)? 2. Does this approach provide meaningful biological information? METHODS: The following contrasts were generated from the 7T MP2RAGE images from 45 healthy controls (age: 19-75, f/m = 23/22) from the ATAG data repository: 1. T1 weighted image (UNI). 2. T1 relaxation image (T1map). 3. INVC/T1map ratio (RATIO). K-means clustering identified 6 clusters/tissue maps (csf, csf/gm-transition, wm, wm/gm transition, heavily myelinated cortical GM (dGM), sparsely myelinated cortical GM (sGM)). These tissue maps were then processed with SPM/DARTEL (volume-based analyses) and Freesurfer (surface-based analyses) and dGM and sGM volume/thickness of young adults (n = 27, 19-27 years) compared to those of older adults (n = 18, 42-75 years) at p<0.001 uncorrected. RESULTS: The resulting maps showed good agreement with histological maps in the literature. Volume- and surface analyses found age-related dGM loss/thinning in the mid-posterior cingulate and parahippocampal/entorhinal gyrus and age-related sGM losses in lateral, mesial and orbitofrontal frontal, insular cortex and superior temporal gyrus. CONCLUSION: The MP2RAGE derived UNI, T1map and RATIO contrasts can be used to identify dGM and sGM. Considering the close relationship between cortical myelo- and cytoarchitecture, the findings reported here indicate that this new technique might provide new insights into the nature of cortical GM loss in physiological and pathological conditions.


Subject(s)
Magnetic Resonance Imaging , Myelin Sheath , Young Adult , Humans , Aged , Adult , Middle Aged , Magnetic Resonance Imaging/methods , Gray Matter , Aging/pathology , Gyrus Cinguli , Brain/pathology
11.
J Alzheimers Dis ; 99(1): 307-319, 2024.
Article in English | MEDLINE | ID: mdl-38669537

ABSTRACT

Background: Alzheimer's disease (AD) pathology is considered to begin in the brainstem, and cerebral microglia are known to play a critical role in AD pathogenesis, yet little is known about brainstem microglia in AD. Translocator protein (TSPO) PET, sensitive to activated microglia, shows high signal in dorsal brainstem in humans, but the precise location and clinical correlates of this signal are unknown. Objective: To define age and AD associations of brainstem TSPO PET signal in humans. Methods: We applied new probabilistic maps of brainstem nuclei to quantify PET-measured TSPO expression over the whole brain including brainstem in 71 subjects (43 controls scanned using 11C-PK11195; 20 controls and 8 AD subjects scanned using 11C-PBR28). We focused on inferior colliculi (IC) because of visually-obvious high signal in this region, and potential relevance to auditory dysfunction in AD. We also assessed bilateral cortex. Results: TSPO expression was normally high in IC and other brainstem regions. IC TSPO was decreased with aging (p = 0.001) and in AD subjects versus controls (p = 0.004). In cortex, TSPO expression was increased with aging (p = 0.030) and AD (p = 0.033). Conclusions: Decreased IC TSPO expression with aging and AD-an opposite pattern than in cortex-highlights underappreciated regional heterogeneity in microglia phenotype, and implicates IC in a biological explanation for strong links between hearing loss and AD. Unlike in cerebrum, where TSPO expression is considered pathological, activated microglia in IC and other brainstem nuclei may play a beneficial, homeostatic role. Additional study of brainstem microglia in aging and AD is needed.


Subject(s)
Aging , Alzheimer Disease , Brain Stem , Microglia , Positron-Emission Tomography , Receptors, GABA , Humans , Alzheimer Disease/pathology , Alzheimer Disease/metabolism , Microglia/metabolism , Microglia/pathology , Male , Aged , Female , Aging/pathology , Brain Stem/metabolism , Brain Stem/pathology , Receptors, GABA/metabolism , Aged, 80 and over , Middle Aged , Isoquinolines , Adult
12.
J Neuropathol Exp Neurol ; 83(6): 396-415, 2024 May 22.
Article in English | MEDLINE | ID: mdl-38613823

ABSTRACT

Limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) is detectable at autopsy in more than one-third of people beyond age 85 years and is robustly associated with dementia independent of other pathologies. Although LATE-NC has a large impact on public health, there remain uncertainties about the underlying biologic mechanisms. Here, we review the literature from human studies that may shed light on pathogenetic mechanisms. It is increasingly clear that certain combinations of pathologic changes tend to coexist in aging brains. Although "pure" LATE-NC is not rare, LATE-NC often coexists in the same brains with Alzheimer disease neuropathologic change, brain arteriolosclerosis, hippocampal sclerosis of aging, and/or age-related tau astrogliopathy (ARTAG). The patterns of pathologic comorbidities provide circumstantial evidence of mechanistic interactions ("synergies") between the pathologies, and also suggest common upstream influences. As to primary mediators of vulnerability to neuropathologic changes, genetics may play key roles. Genes associated with LATE-NC include TMEM106B, GRN, APOE, SORL1, ABCC9, and others. Although the anatomic distribution of TDP-43 pathology defines the condition, important cofactors for LATE-NC may include Tau pathology, endolysosomal pathways, and blood-brain barrier dysfunction. A review of the human phenomenology offers insights into disease-driving mechanisms, and may provide clues for diagnostic and therapeutic targets.


Subject(s)
TDP-43 Proteinopathies , Humans , TDP-43 Proteinopathies/pathology , TDP-43 Proteinopathies/genetics , Aging/pathology , Aging/genetics , Risk Factors , Limbic System/pathology , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Aged, 80 and over , Dementia
13.
Alzheimers Dement ; 20(5): 3495-3503, 2024 May.
Article in English | MEDLINE | ID: mdl-38602280

ABSTRACT

INTRODUCTION: We investigated the association between sleep duration and neuropathologic changes 19 to 40 years later in oldest-old (age 90+) participants of The 90+ Study. METHODS: Participants self-reported sleep duration and underwent neuropathologic evaluation. We categorized sleep duration as < 7, 7 to 8 = reference, > 8 hours and dichotomized neuropathologic changes as present/absent. We estimated odds ratio (OR) and 95% confidence intervals (CI) using logistic regression. RESULTS: In 264 participants, mean age at sleep self-report was 69 years, mean age at autopsy was 98 years, and mean interval between sleep self-report and autopsy was 29 years (range: 19-40). Those reporting > 8 hours of sleep had lower likelihood of limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) inclusions (OR = 0.18; CI = 0.04-0.82) and amyloid beta deposits (OR = 0.34; 95% CI = 0.12-0.94). DISCUSSION: Long self-reported sleep is associated with lower odds of neurodegenerative neuropathologic changes 19 to 40 years later in the oldest-old, suggesting a potential role of sleep in accumulation of dementia-related neuropathologies. HIGHLIGHTS: Association of self-reported sleep with non-Alzheimer's disease neuropathologic changes has not been explored. Whether sleep duration is related to dementia neuropathologic changes decades later is unclear. Long self-reported sleep is associated with lower odds of Alzheimer's disease neuropathologic change 19 to 40 years later in the oldest-old. Long self-reported sleep is associated with lower odds of limbic-predominant age-related TDP-43 encephalopathy neuropathologic change 19 to 40 years later in the oldest-old.


Subject(s)
Brain , Sleep , Humans , Aged, 80 and over , Female , Male , Brain/pathology , Aged , Autopsy , Self Report , Amyloid beta-Peptides/metabolism , Aging/pathology , Sleep Duration
14.
Sci Rep ; 14(1): 9339, 2024 04 23.
Article in English | MEDLINE | ID: mdl-38653745

ABSTRACT

Sensory impairment and brain atrophy is common among older adults, increasing the risk of dementia. Yet, the degree to which multiple co-occurring sensory impairments (MSI across vision, proprioception, vestibular function, olfactory, and hearing) are associated with brain morphometry remain unexplored. Data were from 208 cognitively unimpaired participants (mean age 72 ± 10 years; 59% women) enrolled in the Baltimore Longitudinal Study of Aging. Multiple linear regression models were used to estimate cross-sectional associations between MSI and regional brain imaging volumes. For each additional sensory impairment, there were associated lower orbitofrontal gyrus and entorhinal cortex volumes but higher caudate and putamen volumes. Participants with MSI had lower mean volumes in the superior frontal gyrus, orbitofrontal gyrus, superior parietal lobe, and precuneus compared to participants with < 2 impairments. While MSI was largely associated with lower brain volumes, our results suggest the possibility that MSI was associated with higher basal ganglia volumes. Longitudinal analyses are needed to evaluate the temporality and directionality of these associations.


Subject(s)
Aging , Brain , Humans , Female , Aged , Male , Brain/diagnostic imaging , Brain/pathology , Longitudinal Studies , Cross-Sectional Studies , Aging/physiology , Aging/pathology , Baltimore , Aged, 80 and over , Magnetic Resonance Imaging , Middle Aged , Organ Size , Atrophy
15.
Hear Res ; 446: 109006, 2024 May.
Article in English | MEDLINE | ID: mdl-38583350

ABSTRACT

Hair cells in the cochlear sensory epithelia serve as mechanosensory receptors, converting sound into neuronal signals. The basal sensory epithelia are responsible for transducing high-frequency sounds, while the apex handles low-frequency sounds. Age-related hearing loss predominantly affects hearing at high frequencies and is indicative of damage to the basal sensory epithelia. However, the precise mechanism underlying this site-selective injury remains unclear. In this study, we employed a microscale proteomics approach to examine and compare protein expression in different regions of the cochlear sensory epithelia (upper half and lower half) in 1.5-month-old (normal hearing) and 6-month-old (severe high-frequency hearing loss without hair cell loss) C57BL/6J mice. A total of 2,386 proteins were detected, and no significant differences in protein expression were detected in the upper half of the cochlear sensory epithelia between the two age groups. The expression of 20 proteins in the lower half of the cochlear sensory epithelia significantly differed between the two age groups (e.g., MATN1, MATN4, and AQP1). Moreover, there were 311 and 226 differentially expressed proteins between the upper and lower halves of the cochlear sensory epithelia in 1.5-month-old and 6-month-old mice, respectively. The expression levels of selected proteins were validated by Western blotting. These findings suggest that the spatial differences in protein expression within the cochlear sensory epithelia may play a role in determining the susceptibility of cells at different sites of the cochlea to age-related damage.


Subject(s)
Cochlea , Mice, Inbred C57BL , Presbycusis , Proteomics , Animals , Cochlea/metabolism , Cochlea/pathology , Presbycusis/metabolism , Presbycusis/pathology , Presbycusis/physiopathology , Presbycusis/genetics , Age Factors , Hair Cells, Auditory/metabolism , Hair Cells, Auditory/pathology , Aging/metabolism , Aging/pathology , Disease Models, Animal , Hearing , Epithelium/metabolism , Male , Mice
16.
Neurobiol Aging ; 139: 82-89, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38657394

ABSTRACT

Alterations in grey matter (GM) and white matter (WM) are associated with memory impairment across the neurocognitive aging spectrum and theorised to spread throughout brain networks. Functional and structural connectivity (FC,SC) may explain widespread atrophy. We tested the effect of SC and FC to the hippocampus on cortical thickness (CT) of connected areas. In 419 (223 F) participants (agemean=73 ±â€¯8) from the Alzheimer's Disease Neuroimaging Initiative, cortical regions associated with memory (Rey Auditory Verbal Learning Test) were identified using Lasso regression. Two structural equation models (SEM), for SC and resting-state FC, were fitted including CT areas, and SC and FC to the left and right hippocampus (LHIP,RHIP). LHIP (ß=-0.150,p=<.001) and RHIP (ß=-0.139,p=<.001) SC predicted left temporopolar/rhinal CT; RHIP SC predicted right temporopolar/rhinal CT (ß=-0.191,p=<.001). LHIP SC predicted right fusiform/parahippocampal (ß=-0.104,p=.011) and intraparietal sulcus/superior parietal CT (ß=0.101,p=.028). Increased RHIP FC predicted higher left inferior parietal CT (ß=0.132,p=.042) while increased LHIP FC predicted lower right fusiform/parahippocampal CT (ß=-0.97; p=.023). The hippocampi may be epicentres for cortical thinning through disrupted connectivity.


Subject(s)
Cognitive Aging , Hippocampus , Humans , Aged , Male , Female , Hippocampus/diagnostic imaging , Hippocampus/pathology , Cognitive Aging/physiology , Aged, 80 and over , Memory/physiology , Magnetic Resonance Imaging , White Matter/diagnostic imaging , White Matter/pathology , Cerebral Cortical Thinning/diagnostic imaging , Cerebral Cortical Thinning/pathology , Gray Matter/diagnostic imaging , Gray Matter/pathology , Atrophy , Cerebral Cortex/diagnostic imaging , Cerebral Cortex/pathology , Aging/pathology , Aging/physiology , Aging/psychology , Nerve Net/diagnostic imaging , Nerve Net/pathology , Nerve Net/physiopathology
17.
Nature ; 629(8010): 154-164, 2024 May.
Article in English | MEDLINE | ID: mdl-38649488

ABSTRACT

Muscle atrophy and functional decline (sarcopenia) are common manifestations of frailty and are critical contributors to morbidity and mortality in older people1. Deciphering the molecular mechanisms underlying sarcopenia has major implications for understanding human ageing2. Yet, progress has been slow, partly due to the difficulties of characterizing skeletal muscle niche heterogeneity (whereby myofibres are the most abundant) and obtaining well-characterized human samples3,4. Here we generate a single-cell/single-nucleus transcriptomic and chromatin accessibility map of human limb skeletal muscles encompassing over 387,000 cells/nuclei from individuals aged 15 to 99 years with distinct fitness and frailty levels. We describe how cell populations change during ageing, including the emergence of new populations in older people, and the cell-specific and multicellular network features (at the transcriptomic and epigenetic levels) associated with these changes. On the basis of cross-comparison with genetic data, we also identify key elements of chromatin architecture that mark susceptibility to sarcopenia. Our study provides a basis for identifying targets in the skeletal muscle that are amenable to medical, pharmacological and lifestyle interventions in late life.


Subject(s)
Aging , Muscle, Skeletal , Single-Cell Analysis , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Young Adult , Aging/genetics , Aging/pathology , Aging/physiology , Cell Nucleus/metabolism , Chromatin/metabolism , Chromatin/genetics , Disease Susceptibility , Epigenesis, Genetic , Frailty/genetics , Frailty/pathology , Muscle, Skeletal/cytology , Muscle, Skeletal/metabolism , Muscle, Skeletal/pathology , Muscular Atrophy/genetics , Muscular Atrophy/pathology , Sarcopenia/genetics , Sarcopenia/pathology , Transcriptome
18.
Neurobiol Aging ; 139: 5-10, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38579393

ABSTRACT

Cerebrovascular reactivity (CVR) deficits may contribute to small vessel disease, such as white matter hyperintensities (WMH). Moreover, apolipoprotein-e4 (APOE4) carriers at genetic risk for Alzheimer's disease exhibit cerebrovascular dysfunction relative to non-carriers. We examined whether older adults, and APOE4 carriers specifically, with diminished CVR would exhibit higher WMH burden. Independently living older adults (N = 125, mean age = 69.2 years; SD = 7.6; 31.2% male) free of dementia or clinical stroke underwent brain MRI to quantify cerebral perfusion during CVR to hypercapnia and hypocapnia and determine WMH volume. Adjusting for age, sex and intracranial volume, hierarchical regression analysis revealed a significant association between whole brain CVR to hypercapnia and WMH overall [B = -.02, 95% CI (-.04, -.008), p =.003] and in APOE4 carriers [B = -.03, 95% CI (-.06, -.009), p =.009]. Findings suggest deficits in cerebral vasodilatory capacity are associated with WMH burden in older adults and future studies are warranted to further delineate the effect of APOE4 on precipitating WMH.


Subject(s)
Apolipoprotein E4 , Cerebrovascular Circulation , Magnetic Resonance Imaging , White Matter , Humans , Male , Female , Aged , White Matter/diagnostic imaging , White Matter/pathology , Apolipoprotein E4/genetics , Middle Aged , Aging/pathology , Aging/physiology , Heterozygote , Brain/diagnostic imaging , Brain/pathology , Brain/physiopathology , Brain/blood supply , Hypercapnia/physiopathology , Hypercapnia/diagnostic imaging , Risk , Alzheimer Disease/diagnostic imaging , Alzheimer Disease/genetics , Alzheimer Disease/pathology
19.
Lancet Healthy Longev ; 5(5): e336-e345, 2024 May.
Article in English | MEDLINE | ID: mdl-38582095

ABSTRACT

BACKGROUND: Many studies have reported that impaired gait precedes cognitive impairment in older people. We aimed to characterise the time course of cognitive and motor decline in older individuals and the association of these declines with the pathologies of Alzheimer's disease and related dementias. METHODS: This multicohort study used data from three community-based cohort studies (Religious Orders Study, Rush Memory and Aging Project, and Minority Aging Research Study, all in the USA). The inclusion criteria for all three cohorts were no clinical dementia at the time of enrolment and consent to annual clinical assessments. Eligible participants consented to post-mortem brain donation and had post-mortem pathological assessments and three or more repeated annual measures of cognition and motor functions. Clinical and post-mortem data were analysed using functional mixed-effects models. Global cognition was based on 19 neuropsychological tests, a hand strength score was based on grip and pinch strength, and a gait score was based on the number of steps and time to walk 8 feet and turn 360°. Brain pathologies of Alzheimer's disease and related dementias were assessed at autopsy. FINDINGS: From 1994 to 2022, there were 1570 eligible cohort participants aged 65 years or older, 1303 of whom had cognitive and motor measurements and were included in the analysis. Mean age at death was 90·3 years (SD 6·3), 905 (69%) participants were female, and 398 (31%) were male. Median follow-up time was 9 years (IQR 5-11). On average, cognition was stable from 25 to 15 years before death, when cognition began to decline. By contrast, gait function and hand strength declined during the entire study. The combinations of pathologies of Alzheimer's disease and related dementias associated with cognitive and motor decline and their onsets of associations varied; only tau tangles, Parkinson's disease pathology, and macroinfarcts were associated with decline of all three phenotypes. Tau tangles were significantly associated with cognitive decline, gait function decline, and hand function decline (p<0·0001 for each); however, the association with cognitive decline persisted for more than 11 years before death, but the association with hand strength only began 3·57 years before death and the association with gait began 3·49 years before death. By contrast, the association of macroinfarcts with declining gait function began 9·25 years before death (p<0·0001) compared with 6·65 years before death (p=0·0005) for cognitive decline and 2·66 years before death (p=0·024) for decline in hand strength. INTERPRETATION: Our findings suggest that average motor decline in older adults precedes cognitive decline. Macroinfarcts but not tau tangles are associated with declining gait function that precedes cognitive decline. This suggests the need for further studies to test if gait impairment is a clinical proxy for preclinical vascular cognitive impairment. FUNDING: National Institutes of Health.


Subject(s)
Cognitive Dysfunction , Humans , Male , Female , Aged , Cognitive Dysfunction/pathology , Cognitive Dysfunction/physiopathology , Aged, 80 and over , Cohort Studies , Brain/pathology , Brain/physiopathology , Alzheimer Disease/pathology , Alzheimer Disease/physiopathology , Neuropsychological Tests/statistics & numerical data , Aging/pathology , Aging/physiology , Gait/physiology , Cognition/physiology , Time Factors , Hand Strength/physiology
20.
Biomed Pharmacother ; 174: 116517, 2024 May.
Article in English | MEDLINE | ID: mdl-38574619

ABSTRACT

Age-associated osteosarcopenia is an unresolved syndrome characterized by the concomitant loss of bone (osteopenia) and skeletal muscle (sarcopenia) tissues increasing falls, immobility, morbidity, and mortality. Unbalanced resorption of bone in the remodeling process and excessive protein breakdown, especially fast type II myosin heavy chain (MyHC-II) isoform and myofiber metabolic shift, are the leading causes of bone and muscle deterioration in the elderly, respectively. Equisetum arvense (EQ) is a plant traditionally recommended for many pathological conditions due to its anti-inflammatory properties. Thus, considering that a chronic low-grade inflammatory state predisposes to both osteoporosis and sarcopenia, we tested a standardized hydroalcoholic extract of EQ in in vitro models of muscle atrophy [C2C12 myotubes treated with proinflammatory cytokines (TNFα/IFNγ), excess glucocorticoids (dexamethasone), or the osteokine, receptor activator of nuclear factor kappa-B ligand (RANKL)] and osteoclastogenesis (RAW 264.7 cells treated with RANKL). We found that EQ counteracted myotube atrophy, blunting the activity of several pathways depending on the applied stimulus, and reduced osteoclast formation and activity. By in silico target fishing, IKKB-dependent nuclear factor kappa-B (NF-κB) inhibition emerges as a potential common mechanism underlying EQ's anti-atrophic effects. Consumption of EQ (500 mg/kg/day) by pre-geriatric C57BL/6 mice for 3 months translated into: i) maintenance of muscle mass and performance; ii) restrained myofiber oxidative shift; iii) slowed down age-related modifications in osteoporotic bone, significantly preserving trabecular connectivity density; iv) reduced muscle- and spleen-related inflammation. EQ can preserve muscle functionality and bone remodeling during aging, potentially valuable as a natural treatment for osteosarcopenia.


Subject(s)
Equisetum , Plant Extracts , Sarcopenia , Animals , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , Mice , Sarcopenia/drug therapy , Sarcopenia/pathology , RAW 264.7 Cells , Equisetum/chemistry , Muscle Fibers, Skeletal/drug effects , Muscle Fibers, Skeletal/pathology , Muscle Fibers, Skeletal/metabolism , Aging/drug effects , Aging/pathology , Muscular Atrophy/drug therapy , Muscular Atrophy/pathology , Osteoclasts/drug effects , Osteoclasts/metabolism , Osteoclasts/pathology , RANK Ligand/metabolism , NF-kappa B/metabolism , Osteogenesis/drug effects , Anti-Inflammatory Agents/pharmacology
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