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Muscle Biology and Healing

Overview

Recognition of basic principles of skeletal muscle regeneration and healing processes can help avoid dangers and accelerate return to competition [1]. Emerging findings review the mechanisms that underlie normal versus aberrant muscle-tissue repair [5]. Prevention of fibrosis could enhance muscle regeneration, thereby facilitating more efficient muscle healing [2]. Current strategies in clinical treatment and novel methods for muscle regeneration address the epidemiology of muscle tissue loss, with challenges remaining for future clinical translation [3].

A consistent English terminology and a comprehensive classification system for athletic muscle injuries are presented for use in daily practice [10]. Strategies to minimize muscle damage in proximal nerve injuries include Physical exercises, Electrical stimulation, Medications, Regenerative medicine, and Surgical procedures, with most data coming from experimental animal studies while clinical data remains limited [6]. Immobilization of a muscle laceration resulted in slower muscle regeneration and the development of a large area of scar tissue [8]. Muscles may have a preferred sarcomere length operating range to meet functional demands [25].

Preclinical and clinical studies have demonstrated efficacy of adipose-derived mesenchymal stem cells in muscle, tendon, bone, and cartilage regeneration, although worries about their safety and side effects at long-term remain unsolved [4]. Fatty infiltration in the intact supraspinatus tendon is a normal physiological response with increasing age and female gender, and should be used with caution as an indicator of chronicity or a contraindicating parameter for repair [14].

How It Works

The fundamental biophysics of force transmission, alongside cellular and molecular processes, underlie the repair and regeneration of injured muscle tissue [9].

Satellite Cell Activity: Satellite cells play a key role in skeletal muscle fiber repair and remodeling in response to exercise [7].

Impact of Immobilization: Immobilization results in slower muscle regeneration and the development of a large area of scar tissue [8].

Modulating Fibrosis: Prevention of fibrosis enhances muscle regeneration, thereby facilitating more efficient muscle healing [2]. Simultaneous use of platelet-rich plasma (PRP) and suramin reduces fibrosis in injured muscle and promotes healing without negatively affecting the muscle's contractile properties [13].

Biologic Augmentation: Customized platelet-rich plasma is a promising method to improve PRP's beneficial effect on skeletal muscle repair [11]. The inherent pro-regenerative potential of tissue-specific endothelium could be used therapeutically to orchestrate fibrosis-free healing and to restore homeostasis in tissues [16].

Epigenetic Monitoring: Epigenetic mechanism observations have the potential to become useful tools in sports medicine as predictors of approaching pathophysiological alterations and injury biomarkers that have already taken place [15].

What the Evidence Shows

Emerging findings review the mechanisms that underlie normal versus aberrant muscle-tissue repair [5]. Fundamental biophysics of force transmission and cellular and molecular processes underlie the repair and regeneration of injured muscle tissue after eccentric injury [9]. Genetic determinants of formation or repair of various muscles during different stages of myogenesis are unexpectedly diverse [26].

Diagnostic Assessment: Ultrasonography offers dynamic muscle assessment, is fast, relatively inexpensive, and easier for patients, allowing for detection and severity assessment as well as serial evaluation to follow healing [12]. A consistent English terminology and a comprehensive classification system for athletic muscle injuries proven in daily practice are presented [10].

Conservative and Physical Management: Strategies to minimize muscle damage in proximal nerve injuries include physical exercises, electrical stimulation, medications, regenerative medicine, and surgical procedures [6]. Most data on strategies for muscle preservation in proximal nerve injuries comes from experimental animal studies while clinical data remains limited [6]. Findings from in vivo human studies suggest that satellite cells play a key role in skeletal muscle fiber repair and remodeling in response to exercise [7]. Immobilization resulted in slower muscle regeneration and the development of a large area of scar tissue in muscle lacerations [8].

Surgical Intervention: Early surgical intervention with fasciotomy played a substantial role in allowing optimal muscle regeneration, leading to complete functional recovery in a patient with compartment syndrome and familial rhabdomyolysis [17]. Surgical repair of a clinical tear of the pectoralis major results in greater recovery of peak torque and work performed than conservative management [21]. Outcomes after repair of partial- and full-thickness rotator cuff tears using a bioinductive implant show safety and efficacy at 1-year follow-up [18].

Regenerative and Pharmacologic Strategies: Prevention of fibrosis could enhance muscle regeneration, thereby facilitating more efficient muscle healing [2]. Decorin can efficiently prevent fibrosis and enhance muscle regeneration in lacerated muscle [22]. Simultaneous use of platelet-rich plasma and suramin reduced fibrosis in injured muscle and promoted healing without negatively affecting the muscle's contractile properties [13]. Customized platelet-rich plasma is a promising method to improve PRP's beneficial effect on skeletal muscle repair [11]. Stem cell therapies and tissue engineering offer promising avenues for enhancing skeletal muscle repair, with muscle-derived stem cells showing potential for long-term regeneration and multipotency [19]. Preclinical and clinical studies have demonstrated efficacy of adipose-derived mesenchymal stem cells in muscle, tendon, bone, and cartilage regeneration, but long-term safety and side effects remain unsolved [4]. Single intramuscular administration of muscle precursor cells improved histological outcome and force recovery of injured skeletal muscle in a rat injury model [20]. Current strategies in clinical treatment and novel methods for muscle regeneration face challenges for future clinical translation [3].

Practical Considerations

The fundamental biophysics of force transmission and the cellular and molecular processes underlying the repair and regeneration of injured muscle tissue are described [9]. Emerging findings review the mechanisms that underlie normal versus aberrant muscle-tissue repair [5]. Prevention of fibrosis could enhance muscle regeneration, thereby facilitating more efficient muscle healing [2].

A consistent English terminology as well as a comprehensive classification system for athletic muscle injuries, which is proven in daily practice, are presented [10]. Ultrasonography offers dynamic muscle assessment and is fast, relatively inexpensive, and easier for patients, allowing for detection and severity assessment as well as serial evaluation to follow healing [12]. Fatty infiltration should be used with caution as an indicator of chronicity or a contraindicating parameter for repair [14].

Strategies to minimize muscle damage in proximal nerve injuries include Physical exercises, Electrical stimulation, Medications, Regenerative medicine, and Surgical procedures [6]. Most data on these strategies comes from experimental animal studies while clinical data remains limited [6]. Findings from in vivo human studies suggest that satellite cells play a key role in skeletal muscle fiber repair and remodeling in response to exercise [7].

Current strategies in clinical treatment for muscle tissue loss include novel methods for muscle regeneration, though challenges for their future clinical translation remain [3]. Intense interest has focused on cell-based therapies for chronic, debilitating myopathic diseases [23]. Preclinical and clinical studies have demonstrated efficacy of adipose-derived mesenchymal stem cells in muscle, tendon, bone, and cartilage regeneration, but worries about their safety and side effects at long-term remain unsolved [4]. Customized platelet-rich plasma is a promising method to improve PRP's beneficial effect on skeletal muscle repair [11]. Blood flow restriction exercise aims to clarify how to apply BFR effectively for enhancing strength and hypertrophy while understanding associated safety issues [24].

Key Evidence

  • [L5] Recognition of basic principles of skeletal muscle regeneration and healing processes can help avoid dangers and accelerate return to competition. (10.1177/0363546505274714)
  • [Paper] These results support our hypothesis that prevention of fibrosis could enhance muscle regeneration, thereby facilitating more efficient muscle healing. (10.1152/japplphysiol.00915.2002)
  • [L5] This review provides a comprehensive overview of the epidemiology of muscle tissue loss, highlights current strategies in clinical treatment, and discusses novel methods for muscle regeneration and challenges for their future clinical translation. (10.1155/2018/1984879)
  • [L4] While preclinical and clinical studies have demonstrated efficacy in muscle, tendon, bone, and cartilage regeneration, several worries about their safety and side effects at long-term remain unsolved. (10.3390/ijms20123105)
  • [L5] This article reviews the emerging findings of the mechanisms that underlie normal versus aberrant muscle-tissue repair. (10.1186/2044-5040-1-21)
  • [L5] It outlines various strategies including physical exercises, electrical stimulation, medications, regenerative medicine, and surgical procedures to minimize muscle damage, noting that most data comes from experimental animal studies while clinical data remains limited. (10.1177/17531934231216646)
  • [L5] Findings from in vivo human studies suggest that satellite cells play a key role in skeletal muscle fiber repair and remodeling in response to exercise. (10.3389/fphys.2015.00283)
  • [L5] Immobilization resulted in slower muscle regeneration and the development of a large area of scar tissue. (10.1177/03635465990270021801)
  • [L5] The review describes the fundamental biophysics of force transmission and the cellular and molecular processes underlying the repair and regeneration of injured muscle tissue. (10.1123/jsr.2016-0107)
  • [L5] A consistent English terminology as well as a comprehensive classification system for athletic muscle injuries which is proven in the daily practice are presented. (10.1136/bjsports-2012-091448)
  • [L5] This approach is a promising method to improve PRP's beneficial effect on skeletal muscle repair. (10.1177/2325967116s00143)
  • [L5] Ultrasonography offers dynamic muscle assessment and is fast, relatively inexpensive, and easier for patients, allowing for detection and severity assessment as well as serial evaluation to follow healing. (10.1148/radiol.2017160267)
  • [L5] Simultaneous PRP and suramin use reduced fibrosis in the injured muscle and promoted healing without negatively affecting the muscle's contractile properties. (10.1177/03635465211030295)
  • [L4] Therefore, fatty infiltration should be used with caution as an indicator of chronicity or a contraindicating parameter for repair. (10.1177/17585732211024504)
  • [L4] Epigenetic mechanism observations have the potential to become useful tools in sports medicine, as predictors of approaching pathophysiological alterations and injury biomarkers that have already taken place. (10.3390/genes13081471)
  • [L5] This transformative model has opened a fresh chapter in translational vascular medicine and raised the possibility that the inherent pro-regenerative potential of tissue-specific endothelium could be used therapeutically to orchestrate fibrosis-free healing and to restore homeostasis in tissues. (10.1038/nature17040)
  • [L5] Early surgical intervention with fasciotomy played a substantial role in allowing optimal muscle regeneration, leading to complete functional recovery. (10.2106/00004623-200211000-00021)
  • [L4] Outcomes after repair of partial- and full-thickness rotator cuff tears using a bioinductive implant show safety and efficacy at 1-year follow-up. (10.1016/j.arthro.2019.02.019)
  • [L5] Stem cell therapies and tissue engineering offer promising avenues for enhancing skeletal muscle repair, with muscle-derived stem cells (MDSCs) showing potential for long-term regeneration and multipotency. (10.1016/j.csm.2008.08.009)
  • [Paper] Single intramuscular administration of MPCs improved histological outcome and force recovery of the injured skeletal muscle in a rat injury model. (10.1177/0363546521989235)
  • [L3] Objective strength testing shows that surgical repair of a clinical tear of the pectoralis major results in greater recovery of peak torque and work performed than conservative management. (10.1136/bjsm.35.3.202)
  • [L5] These results suggest that decorin can efficiently prevent fibrosis and enhance muscle regeneration in the lacerated muscle. (10.1177/03635465010290040201)
  • [Paper] Intense interest has focused on cell-based therapies for chronic, debilitating myopathic diseases. (10.1101/gad.1419406)
  • [L2] It aims to clarify how to apply BFR effectively for enhancing strength and hypertrophy while understanding associated safety issues. (10.3389/fphys.2019.00533)
  • [L5] The paper introduces the concept that muscles may have a preferred sarcomere length operating range. (10.1098/rstb.2010.0316)
  • [L5] Genetic determinants of formation or repair of various muscles during different stages of myogenesis are unexpectedly diverse. (10.1097/mco.0b013e328336ea98)

References

[1] Muscle Injuries. The American Journal of Sports Medicine. 2005. DOI: 10.1177/0363546505274714

[2] Antifibrotic effects of suramin in injured skeletal muscle after laceration. Journal of Applied Physiology. 2003. DOI: 10.1152/japplphysiol.00915.2002

[3] Current Methods for Skeletal Muscle Tissue Repair and Regeneration. BioMed Research International. 2018. DOI: 10.1155/2018/1984879

[4] Adipose-Derived Mesenchymal Stem Cells: A Promising Tool in the Treatment of Musculoskeletal Diseases. International Journal of Molecular Sciences. 2019. DOI: 10.3390/ijms20123105

[5] Aberrant repair and fibrosis development in skeletal muscle. Skeletal Muscle. 2011. DOI: 10.1186/2044-5040-1-21

[6] Muscle preservation in proximal nerve injuries: a current update. Journal of Hand Surgery (European Volume). 2024. DOI: 10.1177/17531934231216646

[7] Satellite cells in human skeletal muscle plasticity. Frontiers in Physiology. 2015. DOI: 10.3389/fphys.2015.00283

[8] Suturing Versus Immobilization of a Muscle Laceration. The American Journal of Sports Medicine. 1999. DOI: 10.1177/03635465990270021801

[9] Regeneration of Skeletal Muscle After Eccentric Injury. Journal of Sport Rehabilitation. 2017. DOI: 10.1123/jsr.2016-0107

[10] Terminology and classification of muscle injuries in sport: The Munich consensus statement. British Journal of Sports Medicine. 2012. DOI: 10.1136/bjsports-2012-091448

[11] Customized Platelet-Rich Plasma for Skeletal Muscle Injuries. Orthopaedic Journal of Sports Medicine. 2016. DOI: 10.1177/2325967116s00143

[12] Imaging of Muscle Injuries in Sports Medicine: Sports Imaging Series. Radiology. 2017. DOI: 10.1148/radiol.2017160267

[13] Use of Platelet-Rich Plasma Plus Suramin, an Antifibrotic Agent, to Improve Muscle Healing After Injuries. The American Journal of Sports Medicine. 2021. DOI: 10.1177/03635465211030295

[14] Fatty infiltration in the intact supraspinatus tendon; a normal physiological response with increasing age and female gender. Shoulder & Elbow. 2021. DOI: 10.1177/17585732211024504

[15] Epigenetic Alterations in Sports-Related Injuries. Genes. 2022. DOI: 10.3390/genes13081471

[16] Angiocrine functions of organ-specific endothelial cells. Nature. 2016. DOI: 10.1038/nature17040

[17] COMPARTMENT SYNDROME IN A PATIENT WITH FAMILIAL RHABDOMYOLYSIS. The Journal of Bone and Joint Surgery-American Volume. 2002. DOI: 10.2106/00004623-200211000-00021

[18] Patient‐Reported Outcomes After Use of a Bioabsorbable Collagen Implant to Treat Partial and Full‐Thickness Rotator Cuff Tears. Arthroscopy. 2019. DOI: 10.1016/j.arthro.2019.02.019

[19] Stem Cells for the Treatment of Skeletal Muscle Injury. Clinics in Sports Medicine. 2009. DOI: 10.1016/j.csm.2008.08.009

[20] Muscle Precursor Cells Enhance Functional Muscle Recovery and Show Synergistic Effects With Postinjury Treadmill Exercise in a Muscle Injury Model in Rats. The American Journal of Sports Medicine. 2021. DOI: 10.1177/0363546521989235

[21] Pectoralis major tears: comparison of surgical and conservative treatment. British Journal of Sports Medicine. 2001. DOI: 10.1136/bjsm.35.3.202

[22] The Use of an Antifibrosis Agent to Improve Muscle Recovery after Laceration. The American Journal of Sports Medicine. 2001. DOI: 10.1177/03635465010290040201

[23] Muscle stem cells in development, regeneration, and disease. Genes & Development. 2006. DOI: 10.1101/gad.1419406

[24] Blood Flow Restriction Exercise: Considerations of Methodology, Application, and Safety. Frontiers in Physiology. 2019. DOI: 10.3389/fphys.2019.00533

[25] Skeletal muscle design to meet functional demands. Philosophical Transactions of the Royal Society B: Biological Sciences. 2011. DOI: 10.1098/rstb.2010.0316

[26] Muscle stem cells in developmental and regenerative myogenesis. Current Opinion in Clinical Nutrition and Metabolic Care. 2010. DOI: 10.1097/mco.0b013e328336ea98

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