Aging hinders the effectiveness of regenerative medicine strategies targeting the repair of volumetric muscle loss (VML) injury. Anabolic steroids have been shown to improve several factors which contribute to the age-related decline in muscle's regenerative capacity. In this study, the impact of exogenous nandrolone decanoate (ND) administration on the effectiveness of a VML regenerative repair strategy was explored using an aged animal model. Unilateral tibialis anterior VML injuries were repaired in 18-month-aged animal models (male Fischer 344 rat) using decellularized human skeletal muscle scaffolds supplemented with autologous minced muscle. The contralateral limb was left untreated/uninjured. Following repair, ND(+) or a carrier control (ND-) was delivered via weekly injection for a period of 8 weeks. At 8 weeks, muscle isometric torque, gene expression, and tissue structure were assessed. ND(+) treatment did not improve contractile torque recovery following VML repair when compared to carrier only ND(-) injection controls. Peak isometric torque in the ND(+) VML repair group remained significantly below contralateral uninjured control values (4.69 ± 1.18vs. 7.46 ± 1.53 N mm/kg) and was statistically indistinguishable from carrier only ND(-) VML repair controls (4.47 ± 1.18 N mm/kg). Gene expression for key myogenic genes (Pax7, MyoD, MyoG, IGF-1) were not significantly elevated in response to ND injection, suggesting continued age related myogenic impairment even in the presence of ND(+) treatment. ND injection did reduce the histological appearance of fibrosis at the site of VML repair, and increased expression of the collagen III gene, suggesting some positive effects on repair site matrix regulation. Overall, the results presented in this study suggest that a decline in regenerative capacity with aging may present an obstacle to regenerative medicine strategies targeting VML injury and that the delivery of anabolic stimuli via ND administration was unable to overcome this decline.
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http://dx.doi.org/10.1002/term.3286 | DOI Listing |
Bioengineering (Basel)
December 2024
Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR 97239, USA.
A primary challenge following severe musculoskeletal trauma is incomplete muscle regeneration. Current therapies often fail to heal damaged muscle due to dysregulated healing programs and insufficient revascularization early in the repair process. There is a limited understanding of the temporal changes that occur during the early stages of muscle remodeling in response to engineered therapies.
View Article and Find Full Text PDFStem Cells Int
December 2024
Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Shanghai Stomatological Hospital and School of Stomatology, Fudan University, Shanghai, China.
Int J Biol Macromol
December 2024
Department of Pathology, The Third Affiliated Hospital of Soochow University, Changzhou 213003, China; School of Biology & Basic Medical Sciences, Suzhou Medical College of Soochow University, Soochow University, Suzhou 215123, China. Electronic address:
Volumetric muscle loss (VML) significantly impairs the inherent regenerative ability of skeletal muscle and results in chronic functional impairment. Polysaccharides in the muscle extracellular matrix are crucial for regulating cell proliferation and differentiation. Recent studies indicate that fucoidan has beneficial effects on musculoskeletal conditions.
View Article and Find Full Text PDFSkelet Muscle
October 2024
Department of Molecular Genetics and Microbiology, University of Florida, College of Medicine, Gainesville, FL, 32610, USA.
Background: In recent years, the African spiny mouse Acomys cahirinus has been shown to regenerate a remarkable array of severe internal and external injuries in the absence of a fibrotic response, including the ability to regenerate full-thickness skin excisions, ear punches, severe kidney injuries, and complete transection of the spinal cord. While skeletal muscle is highly regenerative in adult mammals, Acomys displays superior muscle regeneration properties compared with standard laboratory mice following several injuries, including serial cardiotoxin injections of skeletal muscle and volumetric muscle loss (VML) of the panniculus carnosus muscle following full-thickness excision injuries. VML is an extreme muscle injury defined as the irrecoverable ablation of muscle mass, most commonly resulting from combat injuries or surgical debridement.
View Article and Find Full Text PDFJ Funct Morphol Kinesiol
October 2024
Department of Morphological Sciences, Section of Histology, Faculty of Medicine and Nursing, Maimonides Institute for Biomedical Research IMIBIC, Reina Sofía University Hospital, University of Cordoba, 14004 Cordoba, Spain.
Background: In volumetric muscle loss (VML) injuries, spontaneous muscle regeneration capacity is limited. The implantation of autologous adipose tissue in the affected area is an option to treat these lesions; however, the effectiveness of this therapy alone is insufficient for a complete recovery of the damaged muscle. This study examined the influence of treadmill exercise on the rehabilitation of VML injuries reconstructed with autologous adipose tissue, as a strategy to counteract the limitations of spontaneous regeneration observed in these injuries.
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