Aging is a major risk factor for many human diseases, including cognitive impairment, which affects a large population of the elderly. In the past few decades, our understanding of the molecular and cellular mechanisms underlying the changes associated with aging and age-related diseases has expanded greatly, shedding light on the potential role of these changes in cognitive impairment. In this article, we review recent advances in understanding of the mechanisms underlying brain aging under normal and pathological conditions, compare their similarities and differences, discuss the causative and adaptive mechanisms of brain aging, and finally attempt to find some rules to guide us on how to promote healthy aging and prevent age-related diseases.
Humans ; Aged ; Aging/pathology* ; Brain ; Cognitive Dysfunction ; Risk Factors

Audiovisual integration is a vital information process involved in cognition and is closely correlated with aging and Alzheimer's disease (AD). In this review, we evaluated the altered audiovisual integrative behavioral symptoms in AD. We further analyzed the relationships between AD pathologies and audiovisual integration alterations bidirectionally and suggested the possible mechanisms of audiovisual integration alterations underlying AD, including the imbalance between energy demand and supply, activity-dependent degeneration, disrupted brain networks, and cognitive resource overloading. Then, based on the clinical characteristics including electrophysiological and imaging data related to audiovisual integration, we emphasized the value of audiovisual integration alterations as potential biomarkers for the early diagnosis and progression of AD. We also highlighted that treatments targeted audiovisual integration contributed to widespread pathological improvements in AD animal models and cognitive improvements in AD patients. Moreover, investigation into audiovisual integration alterations in AD also provided new insights and comprehension about sensory information processes.
Animals ; Humans ; Alzheimer Disease/pathology* ; Brain/pathology* ; Aging/physiology* ; Cognition

Cell aging is an extremely complex process, which is characterized by mitochondrial structural dysfunction, telomere shortening, inflammatory microenvironment, protein homeostasis imbalance, epigenetic changes, abnormal DNA damage and repair, etc. Aging is usually accompanied by structural and functional damage of tissues and organs which further induces the occurrence and development of aging-related diseases. Aging includes physiological aging caused by increased age and pathological aging induced by a variety of factors. Noteworthy, as a target organ directly contacting with the outside air, lung is more prone to various stimuli, causing pathological premature aging which is lung aging. Studies have found that there is a certain proportion of senescent cells in the lungs of most chronic respiratory diseases. However, the underlying mechanism by which these senescent cells induce lung senescence and their role in chronic respiratory diseases is still obscure. This paper focuses on the causes and classification of lung aging, the internal mechanism of lung aging involved in chronic respiratory diseases, and the application of anti-aging treatments in chronic respiratory diseases. We hope to provide new research ideas and theoretical basis for the clinical prevention and treatment in chronic respiratory diseases.
Aging/pathology* ; Cellular Senescence ; Humans ; Lung/pathology* ; Lung Diseases/pathology* ; Respiration Disorders/pathology* ; Telomere ; Telomere Shortening

Aging-induced changes in the immune system are associated with a higher incidence of infection and vaccination failure. Lymph nodes, which filter the lymph to identify and fight infections, play a central role in this process. However, careful characterization of the impact of aging on lymph nodes and associated autoimmune diseases is lacking. We combined single-cell RNA sequencing (scRNA-seq) with flow cytometry to delineate the immune cell atlas of cervical draining lymph nodes (CDLNs) of both young and old mice with or without experimental autoimmune uveitis (EAU). We found extensive and complicated changes in the cellular constituents of CDLNs during aging. When confronted with autoimmune challenges, old mice developed milder EAU compared to young mice. Within this EAU process, we highlighted that the pathogenicity of T helper 17 cells (Th17) was dampened, as shown by reduced GM-CSF secretion in old mice. The mitigated secretion of GM-CSF contributed to alleviation of IL-23 secretion by antigen-presenting cells (APCs) and may, in turn, weaken APCs' effects on facilitating the pathogenicity of Th17 cells. Meanwhile, our study further unveiled that aging downregulated GM-CSF secretion through reducing both the transcript and protein levels of IL-23R in Th17 cells from CDLNs. Overall, aging altered immune cell responses, especially through toning down Th17 cells, counteracting EAU challenge in old mice.
Aging ; Animals ; Autoimmune Diseases ; Disease Models, Animal ; Granulocyte-Macrophage Colony-Stimulating Factor/metabolism* ; Mice ; Mice, Inbred C57BL ; Th17 Cells/metabolism* ; Uveitis/pathology* ; Virulence

We wanted to determine whether shear wave elastography (SWE) could be used to evaluate the aging degree of the corpus cavernosum (CC) and to identify the histological basis of changes in SWE measurements during the aging process. We performed a cross-sectional study enrolling healthy participants of different ages. We measured the Young's modulus (YM) of the penile CCs by SWE and assessed erectile function using the International Index of Erectile Function-5 (IIEF-5). Histological investigation was performed in surgically resected penile specimens from a separate group of patients to examine the smooth muscle and collagen content of the CCs. Furthermore, we measured the YM, erectile function, smooth muscle, and collagen content of the CCs in different age groups of rats. Finally, we enrolled 210 male volunteers in this study. The YM of the CC (CCYM) was positively correlated with age (r = 0.949, P < 0.01) and negatively correlated with erectile function (r = -0.843, P < 0.01). Histological examinations showed that CCs had increased collagen content but decreased smooth muscle content with increased age. The same positive correlation between CCYM and age was also observed in the animal study. In addition, the animal study showed that older rats, with increased CCYM and decreased erectile function, had lower smooth muscle content and higher collagen content. SWE can noninvasively and quantitatively evaluate the aging degree of the CC. Increased collagen content and decreased smooth muscle content might be the histological basis for the effect of aging on the CC and the increase in its YM.
Humans ; Male ; Rats ; Animals ; Erectile Dysfunction ; Elasticity Imaging Techniques ; Cross-Sectional Studies ; Penis/pathology* ; Penile Erection/physiology* ; Aging ; Collagen

Primary age-related tauopathy (PART) is characterized by the presence of tau neurofibrillary tangles (NFTs) which are typically observed in Alzheimer's disease (AD) brains, with few or without β-amyloid (Aβ) plaques. The diagnosis of PART can be categorized into "definite" or "possible" depending on the amount of Aβ plaques. Definite PART is diagnosed when NFTs are observed and the Braak stage is ≤IV, with Thal Aβ Phase 0 (Crary et al., 2014). According to the neuropathological diagnostic criteria, we reported that PART was frequently observed in the Chinese population according to our findings from specimens in our brain bank, with 47% of brain bank subjects meeting the criteria for PART. There is no consensus on the nature of PART. It remains to be elucidated whether PART is an early form of AD or a novel tauopathy (Duyckaerts et al., 2015; Jellinger et al., 2015).
Aged ; Aged, 80 and over ; Aging/pathology* ; Alzheimer Disease/pathology* ; Brain/pathology* ; Cohort Studies ; Female ; Humans ; Male ; Middle Aged ; Neurofibrillary Tangles/pathology* ; Tauopathies/pathology*

Aging is a complex process associated with dysregulation of the immune system and low levels of inflammation, often associated with the onset of many pathologies. The lacrimal gland (LG) plays a vital role in the maintenance of ocular physiology and changes related to aging directly affect eye diseases. The dysregulation of the immune system in aging leads to quantitative and qualitative changes in antibodies and cytokines. While there is a gradual decline of the immune system, there is an increase in autoimmunity, with a reciprocal pathway between low levels of inflammation and aging mechanisms. Elderly C57BL/6J mice spontaneously show LGs infiltration that is characterized by Th1 but not Th17 cells. The aging of the LG is related to functional alterations, reduced innervation and decreased secretory activities. Lymphocytic infiltration, destruction, and atrophy of glandular parenchyma, ductal dilatation, and secretion of inflammatory mediators modify the volume and composition of tears. Oxidative stress, the capacity to metabolize and eliminate toxic substances decreased in aging, is also associated with the reduction of LG functionality and the pathogenesis of autoimmune diseases. Although further studies are required for a better understanding of autoimmunity and aging of the LG, we described anatomic and immunology aspects that have been described so far.
Aged ; Aging ; Allergy and Immunology ; Animals ; Antibodies ; Atrophy ; Autoimmune Diseases ; Autoimmunity ; Cytokines ; Dilatation ; Eye Diseases ; Humans ; Immune System ; Inflammation ; Lacrimal Apparatus ; Mice ; Ocular Physiological Phenomena ; Oxidative Stress ; Pathology ; Tears ; Th17 Cells

BACKGROUND AND PURPOSE: Semantic memory remains more stable than episodic memory across the lifespan, which makes it potentially useful as a marker for distinguishing pathological aging from normal senescence. To obtain a better understanding of the transitional stage evolving into Alzheimer's dementia (AD), we focused on the amnestic mild cognitive impairment (aMCI) stage stratified based on β-amyloid (Aβ) pathology. METHODS: We analyzed the raw data from Korean version of the Boston Naming Test (K-BNT) and the Controlled Oral Word Association Test (COWAT). For K-BNT, the frequencies of six error types and accuracy rates were evaluated. For a qualitative assessment of the COWAT, we computed the number of switching, number of clusters, and mean cluster size. RESULTS: The data from 217 participants were analyzed (53 normal controls, 66 with Aβ− aMCI, 56 with Aβ+ aMCI, and 42 disease controls). There were fewer semantically related errors and more semantically unrelated errors on the K-BNT in Aβ+ aMCI than in Aβ− aMCI, without a gross difference in the z score. We also found that Aβ+ aMCI showed a more prominent deficit in the number of clusters in the semantic fluency task [especially for animal names (living items)] than Aβ− aMCI. CONCLUSIONS: In spite of similar clinical manifestations, Aβ+ aMCI was more similar to AD than Aβ− aMCI in terms of semantic memory disruption. Semantic memory may serve as an early indicator of brain Aβ pathology. Therefore, semantic memory dysfunction deserves more consideration in clinical practice. Longitudinal research with the follow-up data is needed.
Aging ; Alzheimer Disease ; Animals ; Brain ; Dementia ; Follow-Up Studies ; Humans ; Memory* ; Memory, Episodic ; Mild Cognitive Impairment* ; Pathology ; Semantics* ; Word Association Tests

Advances in cellular and molecular biology underpin most current therapeutic advances in medicine. Such advances for neurological and neurodegenerative diseases are hindered by the lack of similar specimens. It is becoming increasingly evident that greater access to human brain tissue is necessary to understand both the cellular biology of these diseases and their variation. Research in these areas is vital to the development of viable therapeutic options for these currently untreatable diseases. The development and coordination of human brain specimen collection through brain banks is evolving. This perspective article from the Sydney Brain Bank reviews data concerning the best ways to collect and store material for different research purposes.
Aging ; pathology ; physiology ; Biomedical Research ; methods ; Brain ; pathology ; physiopathology ; Humans ; Neurodegenerative Diseases ; pathology ; physiopathology ; therapy ; Tissue Banks ; Tissue Preservation

Primary age-related tauopathy (PART) is characterized by tau neurofibrillary tangles (NFTs) in the absence of amyloid plaque pathology. In the present study, we analyzed the distribution patterns of phosphorylated 43-kDa TAR DNA-binding protein (pTDP-43) in the brains of patients with PART. Immunohistochemistry and immunofluorescence double-labeling in multiple brain regions was performed on brain tissues from PART, Alzheimer's disease (AD), and aging control cases. We examined the regional distribution patterns of pTDP-43 intraneuronal inclusions in PART with Braak NFT stages > 0 and ≤ IV, and a Thal phase of 0 (no beta-amyloid present). We found four stages which indicated potentially sequential dissemination of pTDP-43 in PART. Stage I was characterized by the presence of pTDP-43 lesions in the amygdala, stage II by such lesions in the hippocampus, stage III by spread of pTDP-43 to the neocortex, and stage IV by pTDP-43 lesions in the putamen, pallidum, and insular cortex. In general, the distribution pattern of pTDP-43 pathology in PART cases was similar to the early TDP-43 stages reported in AD, but tended to be more restricted to the limbic system. However, there were some differences in the distribution patterns of pTDP-43 between PART and AD, especially in the dentate gyrus of the hippocampus. Positive correlations were found in PART between the Braak NFT stage and the pTDP-43 stage and density.
Aged ; Aged, 80 and over ; Aging ; metabolism ; pathology ; Brain ; metabolism ; pathology ; DNA-Binding Proteins ; metabolism ; Disease Progression ; Female ; Humans ; Immunohistochemistry ; Inclusion Bodies ; pathology ; Male ; Middle Aged ; Neurofibrillary Tangles ; metabolism ; pathology ; Neurons ; metabolism ; pathology ; Severity of Illness Index ; Tauopathies ; metabolism ; pathology