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Telomere function and attrition with aging. 

Telomere function and attrition with aging. 

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The age-related loss of skeletal muscle mass and function that is associated with sarcopenia can result in ultimate consequences such as decreased quality of life. The causes of sarcopenia are multifactorial and include environmental and biological factors. The purpose of this review is to synthesize what the literature reveals in regards to the ce...

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... this point, telomere length reaches a critical length and the chromosome may become un- capped. This in turn may result in disruption of chromosome integrity because uncapped telomeres activate signaling pathways that correlate with DNA damage and apoptosis (Figure 1) (124). ...
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... re- sults suggest that the microenvironment of aged skeletal muscle suppresses myogenic capability. However, positioning aged skeletal muscle in a young muscle tissue environmental milieu accelerates its repair (9, 13, 139, 145, 169, 170, 172, 173). Hetero- chronic transplantation studies and parabiotically paired mice demonstrate that in the presence of young environment, both aged and young satellite cells are able to fully activate and the muscle is com- pletely repaired (13,173,174). ...

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... Low muscle mass is influenced by various factors, including aging, genetic predisposition, levels of physical activity, dietary habits, and diseases (8,9). Studies indicate that muscle mass and physical function decline with age, even in highly active older individuals, as muscle mass and strength remain significantly lower than in younger counterparts, highlighting the close relationship between low muscle mass and aging (10)(11)(12). ...
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Objective Muscle mass gradually declines with advancing age, and as an anti-aging protein, klotho may be associated with muscle mass. This study aims to explore the relationship between klotho levels and muscle mass in the middle-aged population. Methods Utilizing data from the National Health and Nutrition Examination Survey (NHANES) spanning 2011 to 2018, we conducted a cross-sectional analysis on a cohort of individuals aged 40–59. Weighted multivariable analysis was employed to assess the correlation between klotho and low muscle mass, with stratified and Restricted Cubic Spline (RCS) analyses. Results The cross-sectional investigation revealed a significant negative correlation between klotho levels and the risk of low muscle mass (Model 3: OR = 0.807, 95% CI: 0.712–0.915). A notable interaction between klotho and sex was observed, with a significant interaction effect (P for interaction = 0.01). The risk association was notably higher in females. The risk association was notably higher in females. Additionally, RCS analysis unveiled a significant linear relationship between klotho and low muscle mass (P for nonlinear = 0.9495, P for overall<0.0001). Conclusion Our observational analysis revealed a noteworthy inverse relationship between klotho and low muscle mass, particularly prominent among female participants. This discovery provides crucial insights for the development of more effective intervention strategies and offers a new direction for enhancing muscle quality in the middle-aged population.
... [1] Although sarcopenia is typically correlated with the aging process, lifestyle factors and chronic diseases are also implicated in its occurrence and progression. [2,3] The prevalence of sarcopenia exhibits substantial global variability, ranging from 10% to 27%. [4][5][6] Given the globally expanding aging population, the prevalence of sarcopenia has substantially increased. ...
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Background Previous studies on the association between serum uric acid (UA) levels and sarcopenia have yielded contradictory results. This meta-analysis and literature review assessed the association between serum UA levels and sarcopenia. Moreover, we conducted a comparative analysis of the differences in serum UA concentrations between individuals with and without sarcopenia. Methods A systematic search was conducted across various medical databases, namely PubMed, EMBASE, Web of Science, Cochrane Library, CNKI, and Wanfang (from the start to August 20, 2023). This search focused on published studies that investigated the relationship between serum UA levels and sarcopenia. The relationship between serum UA concentration and the occurrence of sarcopenia was analyzed, and the differences in serum UA concentrations between individuals with sarcopenia and control groups were reviewed. Statistical analysis was performed using STATA 11.0 and R 4.1.3. Results Sixteen studies were considered for our analysis. The results indicated a significant association between low serum UA concentration and a higher sarcopenia risk, particularly among male patients (adjusted odds ratio = 0.65, 95% confidence interval [CI] = 0.49, 0.87, P = .004, I² = 0%). Individuals with sarcopenia exhibited decreased serum UA concentrations compared with those of the control group (mmol/L: weighted mean difference = −28.25, 95% CI = −40.45, −16.05, P < .001; mg/dL: weighted mean difference = −0.82, 95% CI = −1.05, −0.58, P < .001). Additionally, serum UA concentration was positively correlated with skeletal muscle mass index and handgrip strength (skeletal muscle index: correlation coefficient = 0.17, 95% CI = 0.11, 0.22, P < .001; handgrip strength: common odds ratios = 0.10, 95% CI = 0.06, 0.14, P < .001). Conclusion Individuals with sarcopenia have relatively low serum UA concentrations. A notable correlation between serum UA concentration and sarcopenia was observed. Hence, monitoring UA levels could aid in the early detection and treatment of sarcopenia, enabling timely intervention to preserve muscle mass and strength.
... The Forelimb grip strength test assessed skeletal falls, compromised functionality, weakness, and, in extreme cases, mortality (Cruz-Jentoft and Sayer 2019). It has been documented that the content of human muscle tissue progressively diminishes starting from the age of 35, exhibiting a decline of up to 30% in individuals between the ages of 50 and 80 (Arthur and Cooley 2012). Sarcopenia impacts virtually all elderly individuals. ...
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... Karim et al. (2022) Wnt signaling plays an essential role in myogenesis, muscle repair, and stem cell regeneration. Arthur and Cooley, (2012). ...
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... In skeletal muscle, where both AXIN1 and AXIN2 are expressed, AXIN2 plays a more prominent role, particularly in myogenesis [158][159][160]. In this context, AXIN2 can functionally replace AXIN1 in regulating AMPactivated protein kinase (AMPK). ...
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AXIN1, has been initially identified as a prominent antagonist within the WNT/β-catenin signaling pathway, and subsequently unveiled its integral involvement across a diverse spectrum of signaling cascades. These encompass the WNT/β-catenin, Hippo, TGFβ, AMPK, mTOR, MAPK, and antioxidant signaling pathways. The versatile engagement of AXIN1 underscores its pivotal role in the modulation of developmental biological signaling, maintenance of metabolic homeostasis, and coordination of cellular stress responses. The multifaceted functionalities of AXIN1 render it as a compelling candidate for targeted intervention in the realms of degenerative pathologies, systemic metabolic disorders, cancer therapeutics, and anti-aging strategies. This review provides an intricate exploration of the mechanisms governing mammalian AXIN1 gene expression and protein turnover since its initial discovery, while also elucidating its significance in the regulation of signaling pathways, tissue development, and carcinogenesis. Furthermore, we have introduced the innovative concept of the AXIN1-Associated Phosphokinase Complex (AAPC), where the scaffold protein AXIN1 assumes a pivotal role in orchestrating site-specific phosphorylation modifications through interactions with various phosphokinases and their respective substrates.
... 26 Being involved in muscle repair, Wnt signalling activation resulted impaired in the aged skeletal muscle; particularly, the imbalance of Wnt and Notch signalling pathways leads to the age-related decrease in muscle regenerative capacity. 27 Wnt pathway is also strictly connected to cadherin signalling pathway: In C2C12 cell line, it was demonstrated that M-cadherin regulates β-catenin phosphorylation and, consequently, the Wnt cascade and, thus, affects myogenesis. 28 FGF signalling pathway is essential for skeletal muscle stem cells and its deregulation could lead to decrease of stem cell self-renewal and, consequently, muscle wasting. ...
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... Once received, these signals are passed into host cells to modulate cell growth and renewal. Notable examples of such transmembrane structures include connexins [47], pannexins [48], notch [49,50], and low-density lipoprotein receptor-related proteins 5/6 (Lrp5/6) [51][52][53]. ...
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... Muscle mass, strength and function are progressively lost with aging [1]. A loss or reduction in skeletal muscle function often leads to increased morbidity and mortality either directly, or indirectly, via the development of secondary diseases such as diabetes, obesity and cardiovascular disease [1,2]. Maintaining skeletal muscle function throughout the lifespan into old age is essential for independent living and good health. ...
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... 250 It has been reported that Notch signaling is impaired in regenerating aged skeletal muscle, which can be restored by physiological stimuli of exercise. [251][252][253] Therefore, further researches should be carried out to demonstrate the underlying mechanisms of mechanotransduction mediated tissue regeneration with different exercise types, which may provide the novel targets for clinical interventions (Fig. 2). ...
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Physical activity has been known as an essential element to promote human health for centuries. Thus, exercise intervention is encouraged to battle against sedentary lifestyle. Recent rapid advances in molecular biotechnology have demonstrated that both endurance and resistance exercise training, two traditional types of exercise, trigger a series of physiological responses, unraveling the mechanisms of exercise regulating on the human body. Therefore, exercise has been expected as a candidate approach of alleviating a wide range of diseases, such as metabolic diseases, neurodegenerative disorders, tumors, and cardiovascular diseases. In particular, the capacity of exercise to promote tissue regeneration has attracted the attention of many researchers in recent decades. Since most adult human organs have a weak regenerative capacity, it is currently a key challenge in regenerative medicine to improve the efficiency of tissue regeneration. As research progresses, exercise-induced tissue regeneration seems to provide a novel approach for fighting against injury or senescence, establishing strong theoretical basis for more and more “exercise mimetics.” These drugs are acting as the pharmaceutical alternatives of those individuals who cannot experience the benefits of exercise. Here, we comprehensively provide a description of the benefits of exercise on tissue regeneration in diverse organs, mainly focusing on musculoskeletal system, cardiovascular system, and nervous system. We also discuss the underlying molecular mechanisms associated with the regenerative effects of exercise and emerging therapeutic exercise mimetics for regeneration, as well as the associated opportunities and challenges. We aim to describe an integrated perspective on the current advances of distinct physiological mechanisms associated with exercise-induced tissue regeneration on various organs and facilitate the development of drugs that mimics the benefits of exercise.