Skeletal muscle regenerative potential declines with age, in part due to deficiencies in resident stem cells (satellite cells, SCs) and derived myogenic progenitors (MPs); however, the factors responsible for this decline remain obscure. TGFβ superfamily signaling is an inhibitor of myogenic differentiation, with elevated activity in aged skeletal muscle. Surprisingly, we find reduced expression of , the downstream cofactor for canonical TGFβ superfamily signaling, and the target in aged SCs and MPs during regeneration. Specific deletion of Smad4 in adult mouse SCs led to increased propensity for terminal myogenic commitment connected to impaired proliferative potential. Furthermore, SC-specific Smad4 disruption compromised adult skeletal muscle regeneration. Finally, loss of Smad4 in aged SCs did not promote aged skeletal muscle regeneration. Therefore, SC-specific reduction of Smad4 is a feature of aged regenerating skeletal muscle and Smad4 is a critical regulator of SC and MP amplification during skeletal muscle regeneration.
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http://dx.doi.org/10.7554/eLife.19484 | DOI Listing |
Ophthalmic Plast Reconstr Surg
January 2025
Division of Orbital and Ophthalmic Plastic Surgery, Jules Stein Eye Institute, University of California, Los Angeles, California, U.S.A.
Purpose: Phenylephrine testing prior to Müller muscle conjunctival resection has traditionally been used to predict postoperative outcomes. The purpose of this study is to determine if preoperative phenylephrine testing impacts postoperative changes in eyelid position.
Methods: In this multicenter cross-sectional cohort study, 270 eyelids of participants with involutional ptosis and levator function >12 mm who underwent Müller muscle conjunctival resection were divided into 2 comparison groups.
PLoS One
January 2025
Faculty of Biology, School of Health Sciences, Medicine & Health, University of Manchester, Manchester, United Kingdom.
Background: Despite the comparatively high prevalence of possible sarcopenia among young-old adults in the community, there is currently no available and effective social media-based intervention to increase the awareness and change the behavior of the target population to prevent sarcopenia. Using co-design methodology, we developed a multicomponent intervention strategy of health education and exercise for sarcopenia prevention utilizing the TikTok platform.
Objectives: The primary purpose of this study is to examine the feasibility and acceptability of the social media-based intervention to enhance muscle function in community-dwelling young-old adults with possible sarcopenia.
Bioinformatics
January 2025
Department of Robotics & Mechatronics Engineering, DGIST, Daegu, 42988, South Korea.
Motivation: Skeletal muscle cells (skMCs) combine together to create long, multi-nucleated structures called myotubes. By studying the size, length, and number of nuclei in these myotubes, we can gain a deeper understanding of skeletal muscle development. However, human experimenters may often derive unreliable results owing to the unusual shape of the myotube, which causes significant measurement variability.
View Article and Find Full Text PDFNeuromolecular Med
January 2025
Department of Rehabilitation Medicine, The Affiliated Jiangning Hospital of Nanjing Medical University, No. 168 Gushan Road, Dongshan Street, Jiangning District, Nanjing, 211199, Jiangsu, China.
Muscle atrophy in pathological or diseased muscles arises from an imbalance between protein synthesis and degradation. Elevated levels of interleukin-6 (IL-6) are a hallmark of ischemic stroke and have been associated with muscle atrophy in certain pathological contexts. However, the mechanisms by which IL-6 induces muscle atrophy in the context of stroke remain unclear.
View Article and Find Full Text PDFEur J Nutr
January 2025
School of Physical Education and Sport Science, National and Kapodistrian University of Athens, 17237, Athens, Greece.
Purpose: Protein supplementation has been proposed as an effective dietary strategy for maintaining or increasing skeletal muscle mass and improving physical performance in middle-aged and older adults. Diabetes mellitus exacerbates muscle mass loss, leading to many older adults with type 2 diabetes mellitus (T2DM) experiencing sarcopenia, and vice versa. Our objective was to assess the impact of increased dietary protein intake on muscle mass, strength, physical performance, and the progression of T2DM in middle-aged and older adults diagnosed with this condition.
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