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Graça AL, Gomez-Florit M, Gomes ME, Docheva D. Tendon Aging. Subcell Biochem 2023; 103:121-147. [PMID: 37120467 DOI: 10.1007/978-3-031-26576-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Tendons are mechanosensitive connective tissues responsible for the connection between muscles and bones by transmitting forces that allow the movement of the body, yet, with advancing age, tendons become more prone to degeneration followed by injuries. Tendon diseases are one of the main causes of incapacity worldwide, leading to changes in tendon composition, structure, and biomechanical properties, as well as a decline in regenerative potential. There is still a great lack of knowledge regarding tendon cellular and molecular biology, interplay between biochemistry and biomechanics, and the complex pathomechanisms involved in tendon diseases. Consequently, this reflects a huge need for basic and clinical research to better elucidate the nature of healthy tendon tissue and also tendon aging process and associated diseases. This chapter concisely describes the effects that the aging process has on tendons at the tissue, cellular, and molecular levels and briefly reviews potential biological predictors of tendon aging. Recent research findings that are herein reviewed and discussed might contribute to the development of precision tendon therapies targeting the elderly population.
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Affiliation(s)
- Ana Luísa Graça
- 3B's Research Group, I3Bs-Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Manuel Gomez-Florit
- Health Research Institute of the Balearic Islands (IdISBa), Palma de Mallorca, Spain
| | - Manuela Estima Gomes
- 3B's Research Group, I3Bs-Research Institute on Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Guimarães, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Denitsa Docheva
- Department of Musculoskeletal Tissue Regeneration, Orthopaedic Hospital König-Ludwig-Haus, University of Würzburg, Würzburg, Germany.
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Japjec M, Horvat Pavlov K, Petrovic A, Staresinic M, Sebecic B, Buljan M, Vranes H, Giljanovic A, Drmic D, Japjec M, Prtoric A, Lovric E, Batelja Vuletic L, Dobric I, Boban Blagaic A, Skrtic A, Seiwerth S, Predrag S. Stable Gastric Pentadecapeptide BPC 157 as a Therapy for the Disable Myotendinous Junctions in Rats. Biomedicines 2021; 9:biomedicines9111547. [PMID: 34829776 PMCID: PMC8615275 DOI: 10.3390/biomedicines9111547] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 10/08/2021] [Accepted: 10/23/2021] [Indexed: 12/17/2022] Open
Abstract
(1) Aim: The stable gastric pentadecapeptide BPC 157 is known to heal transected muscle, tendon, and ligament. Thereby, in this study, we investigated the effect of BPC 157 on the dissection of the quadriceps tendon from the quadriceps muscle in rats. (2) Materials and Methods: Myotendinous junction defect, which cannot heal spontaneously in rats, as evidenced with consistent macro/microscopic, biomechanical, functional assessments, eNOS, and COX-2 mRNA levels and oxidative stress and NO-levels in the myotendinous junctions. BPC 157 (10 µg/kg, 10 ng/kg) regimen was given (i) intraperitoneally, first application immediately after surgery, last 24 h before sacrifice; (ii) per-orally, in drinking water (0.16 µg/mL, 0.16 ng/mL, 12 mL/rat/day), till the sacrifice at 7, 14, 28 and 42 postoperative days. (3) Results: These BPC 157 regimens document prominent therapy effects (macro/microscopic, biomechanical, functional much like eNOS and COX-2 mRNA levels and counteracted oxidative stress and NO-levels in the myotendinous junctions), while controls have a poor presentation. Especially, in rats with the disabled myotendinous junction, along with full functional recovery, BPC 157 counteracts muscle atrophy that is regularly progressive and brings muscle presentation close to normal. Accordingly, unlike the perilous course in controls, those rats, when receiving BPC 157 therapy, exhibit a smaller defect, and finally defects completely disappear. Microscopically, there are no more inflammatory infiltrate, well-oriented recovered tissue of musculotendon junction appears in BPC 157 treated rats at the 28 days and 42 days. (4) Conclusions: BPC 157 restores myotendinous junction in accordance with the healing of the transected muscle, tendon, and ligament.
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Affiliation(s)
- Mladen Japjec
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (M.J.); (M.S.); (B.S.); (A.P.); (I.D.)
| | - Katarina Horvat Pavlov
- Department of Pathology, School of Medicine, University of Zagreb, P.O. Box 910, Salata 10, 10000 Zagreb, Croatia; (K.H.P.); (A.P.); (E.L.); (L.B.V.); (S.S.)
| | - Andreja Petrovic
- Department of Pathology, School of Medicine, University of Zagreb, P.O. Box 910, Salata 10, 10000 Zagreb, Croatia; (K.H.P.); (A.P.); (E.L.); (L.B.V.); (S.S.)
| | - Mario Staresinic
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (M.J.); (M.S.); (B.S.); (A.P.); (I.D.)
| | - Bozidar Sebecic
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (M.J.); (M.S.); (B.S.); (A.P.); (I.D.)
| | - Matko Buljan
- Department of Pharmacology, School of Medicine, University of Zagreb, P.O. Box, 916, Salata 11, 10000 Zagreb, Croatia; (M.B.); (H.V.); (A.G.); (D.D.); (M.J.); (A.B.B.)
| | - Hrvoje Vranes
- Department of Pharmacology, School of Medicine, University of Zagreb, P.O. Box, 916, Salata 11, 10000 Zagreb, Croatia; (M.B.); (H.V.); (A.G.); (D.D.); (M.J.); (A.B.B.)
| | - Ana Giljanovic
- Department of Pharmacology, School of Medicine, University of Zagreb, P.O. Box, 916, Salata 11, 10000 Zagreb, Croatia; (M.B.); (H.V.); (A.G.); (D.D.); (M.J.); (A.B.B.)
| | - Domagoj Drmic
- Department of Pharmacology, School of Medicine, University of Zagreb, P.O. Box, 916, Salata 11, 10000 Zagreb, Croatia; (M.B.); (H.V.); (A.G.); (D.D.); (M.J.); (A.B.B.)
| | - Miroslav Japjec
- Department of Pharmacology, School of Medicine, University of Zagreb, P.O. Box, 916, Salata 11, 10000 Zagreb, Croatia; (M.B.); (H.V.); (A.G.); (D.D.); (M.J.); (A.B.B.)
| | - Andreja Prtoric
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (M.J.); (M.S.); (B.S.); (A.P.); (I.D.)
| | - Eva Lovric
- Department of Pathology, School of Medicine, University of Zagreb, P.O. Box 910, Salata 10, 10000 Zagreb, Croatia; (K.H.P.); (A.P.); (E.L.); (L.B.V.); (S.S.)
| | - Lovorka Batelja Vuletic
- Department of Pathology, School of Medicine, University of Zagreb, P.O. Box 910, Salata 10, 10000 Zagreb, Croatia; (K.H.P.); (A.P.); (E.L.); (L.B.V.); (S.S.)
| | - Ivan Dobric
- Department of Surgery, School of Medicine, University of Zagreb, 10000 Zagreb, Croatia; (M.J.); (M.S.); (B.S.); (A.P.); (I.D.)
| | - Alenka Boban Blagaic
- Department of Pharmacology, School of Medicine, University of Zagreb, P.O. Box, 916, Salata 11, 10000 Zagreb, Croatia; (M.B.); (H.V.); (A.G.); (D.D.); (M.J.); (A.B.B.)
| | - Anita Skrtic
- Department of Pathology, School of Medicine, University of Zagreb, P.O. Box 910, Salata 10, 10000 Zagreb, Croatia; (K.H.P.); (A.P.); (E.L.); (L.B.V.); (S.S.)
- Correspondence: (A.S.); (S.P.); Tel.: +385-1-4566-980 (A.S.); +385-1-4566-833 (S.P.); Fax: +385-1-492-0050 (A.S. & S.P.)
| | - Sven Seiwerth
- Department of Pathology, School of Medicine, University of Zagreb, P.O. Box 910, Salata 10, 10000 Zagreb, Croatia; (K.H.P.); (A.P.); (E.L.); (L.B.V.); (S.S.)
| | - Sikiric Predrag
- Department of Pharmacology, School of Medicine, University of Zagreb, P.O. Box, 916, Salata 11, 10000 Zagreb, Croatia; (M.B.); (H.V.); (A.G.); (D.D.); (M.J.); (A.B.B.)
- Correspondence: (A.S.); (S.P.); Tel.: +385-1-4566-980 (A.S.); +385-1-4566-833 (S.P.); Fax: +385-1-492-0050 (A.S. & S.P.)
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Yuan C, Arora A, Garofalo AM, Grange RW. Potential cross-talk between muscle and tendon in Duchenne muscular dystrophy. Connect Tissue Res 2021; 62:40-52. [PMID: 32867551 DOI: 10.1080/03008207.2020.1810247] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE To describe potential signaling (cross-talk) between dystrophic skeletal muscle and tendon in Duchenne muscular dystrophy. MATERIALS AND METHODS Review of Duchenne muscular dystrophy and associated literature relevant to muscle-tendon cross-talk. RESULTS AND CONCLUSIONS Duchenne muscular dystrophy results from the absence of the protein dystrophin and the associated dystrophin - glycoprotein complex, which are thought to provide both structural support and signaling functions for the muscle fiber. In addition, there are other potential signal pathways that could represent cross-talk between muscle and tendon, particularly at the myotendinous junction. Duchenne muscular dystrophy is characterized by multiple pathophysiologic mechanisms. Herein, we explore three of these: (1) the extracellular matrix, fibrosis, and fat deposition; (2) satellite cells; and (3) tensegrity. A key signaling protein that emerged in each was transforming growth factor - beta one (TGF-β1).].
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Affiliation(s)
- Claire Yuan
- Department of Human Nutrition, Foods, and Exercise and Metabolism Core, Virginia Tech , Blacksburg, Virginia, USA
| | - Ashwin Arora
- Department of Human Nutrition, Foods, and Exercise and Metabolism Core, Virginia Tech , Blacksburg, Virginia, USA
| | - Anthony M Garofalo
- Department of Human Nutrition, Foods, and Exercise and Metabolism Core, Virginia Tech , Blacksburg, Virginia, USA
| | - Robert W Grange
- Department of Human Nutrition, Foods, and Exercise and Metabolism Core, Virginia Tech , Blacksburg, Virginia, USA
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Abstract
Tendons connect muscles to bones, ensuring joint movement. With advanced age, tendons become more prone to degeneration followed by injuries. Tendon repair often requires lengthy periods of rehabilitation, especially in elderly patients. Existing medical and surgical treatments often fail to regain full tendon function. The development of novel treatment methods has been hampered due to limited understanding of basic tendon biology. Recently, it was discovered that tendons, similar to other mesenchymal tissues, contain tendon stem/progenitor cells (TSPCs) which possess the common stem cell properties. The current strategies for enhancing tendon repair consist mainly of applying stem cells, growth factors, natural and artificial biomaterials alone or in combination. In this review, we summarise the basic biology of tendon tissues and provide an update on the latest repair proposals for tendon tears.
Cite this article: EFORT Open Rev 2017;2:332-342. DOI: 10.1302/2058-5241.2.160075
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Affiliation(s)
- Fan Wu
- Experimental Surgery and Regenerative Medicine, Department of Surgery, Ludwig-Maximilians-University (LMU), Munich, Germany
| | - Michael Nerlich
- Department of Trauma Surgery, University Regensburg Medical Center, Regensburg, Germany
| | - Denitsa Docheva
- Experimental Trauma Surgery, Department of Trauma Surgery, University Regensburg Medical Center, Regensburg, Germany and Department of Medical Biology, Medical University-Plovdiv, Plovdiv, Bulgaria
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5
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Contreras-Muñoz P, Torrella JR, Serres X, Rizo-Roca D, De la Varga M, Viscor G, Martínez-Ibáñez V, Peiró JL, Järvinen TAH, Rodas G, Marotta M. Postinjury Exercise and Platelet-Rich Plasma Therapies Improve Skeletal Muscle Healing in Rats But Are Not Synergistic When Combined. Am J Sports Med 2017; 45:2131-2141. [PMID: 28453295 DOI: 10.1177/0363546517702864] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Skeletal muscle injuries are the most common sports-related injury and a major concern in sports medicine. The effect of platelet-rich plasma (PRP) injections on muscle healing is still poorly understood, and current data are inconclusive. PURPOSE To evaluate the effects of an ultrasound-guided intramuscular PRP injection, administered 24 hours after injury, and/or posttraumatic daily exercise training for 2 weeks on skeletal muscle healing in a recently established rat model of skeletal muscle injury that highly mimics the muscle trauma seen in human athletes. STUDY DESIGN Controlled laboratory study. METHODS A total of 40 rats were assigned to 5 groups. Injured rats (medial gastrocnemius injury) received a single PRP injection (PRP group), daily exercise training (Exer group), or a combination of a single PRP injection and daily exercise training (PRP-Exer group). Untreated and intramuscular saline-injected animals were used as controls. Muscle force was determined 2 weeks after muscle injury, and muscles were harvested and evaluated by means of histological assessment and immunofluorescence microscopy. RESULTS Both PRP (exhibiting 4.8-fold higher platelet concentration than whole blood) and exercise training improved muscle strength (maximum tetanus force, TetF) in approximately 18%, 20%, and 30% of rats in the PRP, PRP-Exer, and Exer groups, respectively. Specific markers of muscle regeneration (developmental myosin heavy chain, dMHC) and scar formation (collagen I) demonstrated the beneficial effect of the tested therapies in accelerating the muscle healing process in rats. PRP and exercise treatments stimulated the growth of newly formed regenerating muscle fibers (1.5-, 2-, and 2.5-fold increase in myofiber cross-sectional area in PRP, PRP-Exer, and Exer groups, respectively) and reduced scar formation in injured skeletal muscle (20%, 34%, and 41% of reduction in PRP, PRP-Exer, and Exer groups, respectively). Exercise-treated muscles (PRP-Exer and Exer groups) had significantly reduced percentage of dMHC-positive regenerating fibers (35% and 47% decrease in dMHC expression, respectively), indicating that exercise therapies accelerated the muscle healing process witnessed by the more rapid replacement of the embryonic-developmental myosin isoform by mature muscle myosin isoforms. CONCLUSION Intramuscular PRP injection and, especially, treadmill exercise improve histological outcome and force recovery of the injured skeletal muscle in a rat injury model that imitates sports-related muscle injuries in athletes. However, there was not a synergistic effect when both treatments were combined, suggesting that PRP does not add any beneficial effect to exercise-based therapy in the treatment of injured skeletal muscle. CLINICAL RELEVANCE This study demonstrates the efficacy of an early active rehabilitation protocol or single intramuscular PRP injection on muscle recovery. The data also reveal that the outcome of the early active rehabilitation is adversely affected by the PRP injection when the two therapies are combined, and this could explain why PRP therapies have failed in randomized clinical trials where the athletes have adhered to postinjection rehabilitation protocols based on the principle of early, active mobilization.
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Affiliation(s)
- Paola Contreras-Muñoz
- Leitat Foundation, Leitat Technological Center, Barcelona, Spain.,Bioengineering, Cell Therapy and Surgery in Congenital Malformations Laboratory, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Joan Ramon Torrella
- Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Xavier Serres
- Ultrasound Unit, Department of Radiology, Hospital Universitari Vall d'Hebron, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - David Rizo-Roca
- Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | | | - Ginés Viscor
- Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Vicente Martínez-Ibáñez
- Bioengineering, Cell Therapy and Surgery in Congenital Malformations Laboratory, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - José Luis Peiró
- Bioengineering, Cell Therapy and Surgery in Congenital Malformations Laboratory, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain.,Translational Research in Fetal Surgery for Congenital Malformations Laboratory, Center for Fetal, Cellular and Molecular Therapy, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Tero A H Järvinen
- Medical School, University of Tampere and Tampere University Hospital, Tampere, Finland
| | - Gil Rodas
- Leitat Foundation, Leitat Technological Center, Barcelona, Spain.,Medical Services, Futbol Club Barcelona, Ciutat Esportiva Futbol Club Barcelona, Barcelona, Spain
| | - Mario Marotta
- Leitat Foundation, Leitat Technological Center, Barcelona, Spain.,Bioengineering, Cell Therapy and Surgery in Congenital Malformations Laboratory, Vall d'Hebron Institut de Recerca, Universitat Autònoma de Barcelona, Barcelona, Spain
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6
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Karzis K, Kalogeris M, Mandalidis D, Geladas N, Karteroliotis K, Athanasopoulos S. The effect of foot overpronation on Achilles tendon blood supply in healthy male subjects. Scand J Med Sci Sports 2016; 27:1114-1121. [DOI: 10.1111/sms.12722] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/23/2016] [Indexed: 11/30/2022]
Affiliation(s)
- K. Karzis
- Department of Physiotherapy; Asklipieio General Hospital of Voula; Athens Greece
| | - M. Kalogeris
- Department of Medical Imaging; Medical Centre Palaiou Falirou; Athens Greece
| | - D. Mandalidis
- School of Physical Education and Sport Science; Department of Sport Medicine and Biology of Exercise; National and Kapodistrian University of Athens; Athens Greece
| | - N. Geladas
- School of Physical Education and Sport Science; Department of Sport Medicine and Biology of Exercise; National and Kapodistrian University of Athens; Athens Greece
| | - K. Karteroliotis
- School of Physical Education and Sport Science; Department of Sport Medicine and Biology of Exercise; National and Kapodistrian University of Athens; Athens Greece
| | - S. Athanasopoulos
- School of Physical Education and Sport Science; Department of Sport Medicine and Biology of Exercise; National and Kapodistrian University of Athens; Athens Greece
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7
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Curzi D. Ultrastructural study of myotendinous junction plasticity: from disuse to exercise. SPORT SCIENCES FOR HEALTH 2016. [DOI: 10.1007/s11332-016-0301-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Zhang C, Ferrari R, Beezhold K, Stearns-Reider K, D'Amore A, Haschak M, Stolz D, Robbins PD, Barchowsky A, Ambrosio F. Arsenic Promotes NF-Κb-Mediated Fibroblast Dysfunction and Matrix Remodeling to Impair Muscle Stem Cell Function. Stem Cells 2016; 34:732-42. [PMID: 26537186 DOI: 10.1002/stem.2232] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 09/14/2015] [Indexed: 12/19/2022]
Abstract
Arsenic is a global health hazard that impacts over 140 million individuals worldwide. Epidemiological studies reveal prominent muscle dysfunction and mobility declines following arsenic exposure; yet, mechanisms underlying such declines are unknown. The objective of this study was to test the novel hypothesis that arsenic drives a maladaptive fibroblast phenotype to promote pathogenic myomatrix remodeling and compromise the muscle stem (satellite) cell (MuSC) niche. Mice were exposed to environmentally relevant levels of arsenic in drinking water before receiving a local muscle injury. Arsenic-exposed muscles displayed pathogenic matrix remodeling, defective myofiber regeneration and impaired functional recovery, relative to controls. When naïve human MuSCs were seeded onto three-dimensional decellularized muscle constructs derived from arsenic-exposed muscles, cells displayed an increased fibrogenic conversion and decreased myogenicity, compared with cells seeded onto control constructs. Consistent with myomatrix alterations, fibroblasts isolated from arsenic-exposed muscle displayed sustained expression of matrix remodeling genes, the majority of which were mediated by NF-κB. Inhibition of NF-κB during arsenic exposure preserved normal myofiber structure and functional recovery after injury, suggesting that NF-κB signaling serves as an important mechanism of action for the deleterious effects of arsenic on tissue healing. Taken together, the results from this study implicate myomatrix biophysical and/or biochemical characteristics as culprits in arsenic-induced MuSC dysfunction and impaired muscle regeneration. It is anticipated that these findings may aid in the development of strategies to prevent or revert the effects of arsenic on tissue healing and, more broadly, provide insight into the influence of the native myomatrix on stem cell behavior.
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Affiliation(s)
- Changqing Zhang
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Ricardo Ferrari
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kevin Beezhold
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Kristen Stearns-Reider
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Antonio D'Amore
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Martin Haschak
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Donna Stolz
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Paul D Robbins
- Department of Metabolism and Aging, The Scripps Research Institute, Jupiter, Florida, USA
| | - Aaron Barchowsky
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Fabrisia Ambrosio
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.,Department of Physical Therapy, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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9
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Jiang S, Gao Y, Zhang Y, Liu K, Wang H, Goswami N. The research on the formation mechanism of extraordinary oxidative capacity of skeletal muscle in hibernating ground squirrels ( Spermophilus dauricus). Zool Stud 2015; 54:e46. [PMID: 31966133 DOI: 10.1186/s40555-015-0124-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 06/08/2015] [Indexed: 11/10/2022]
Abstract
BACKGROUND Previous studies indicate that hibernating animals, under conditions of torpor for long periods, show an increased oxidative muscle fibers (type I) ratio and a decreased glycolytic muscle fibers (type II) ratio in skeletal muscle and accompanied by extraordinary oxidative ability. This observation is completely contrasted with non-hibernators, which show a shift of oxidative muscle fibers (type I) to glycolytic muscle fibers (type II). Presently, the mechanisms by which these changes occur remain unclear. To investigate the mechanism of high oxidative capacity of the skeletal muscles in hibernating ground squirrels, capillary density (CD), and capillary/fiber (C/F) were measured by immunohistochemistry. mRNA expression levels of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were determined using real-time quantitative PCR assay. Spectrophotometry was applied to determine the activities of hexokinase (PK), pyruvate kinase (HK), and cytochrome c oxidase (CcO). RESULTS Inthe soleus muscle (SOL), mRNA expression levels of HIF-1αandVEGF in torpor became slightly lower but were not statistically significant; they were, however, significantly higher in the arousal group. In hibernating animals, no significant change occurred in CD but C/F increased by 15 %. CcO showed the highest activity in torpor. There were no significant differences in the activities of HK and PK between the torpid animals and summer active animals in SOL. However, PK activity increased by 34 % after hibernation. CONCLUSIONS Oxidative capacitymay be ensured by an increase of capillary supply of skeletal muscle in hibernating animals.
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Affiliation(s)
- Shanfeng Jiang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 71069, China
| | - Yunfang Gao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 71069, China
| | - Yangmei Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 71069, China
| | - Kun Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 71069, China
| | - Huiping Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an 71069, China
| | - Nandu Goswami
- Institute of Physiology, Center of Physiological Medicine, Medical University Graz, Graz, Austria
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10
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Yao J, Woon CYL, Behn A, Korotkova T, Park DY, Gajendran V, Smith RL. The effect of suture coated with mesenchymal stem cells and bioactive substrate on tendon repair strength in a rat model. J Hand Surg Am 2012; 37:1639-45. [PMID: 22727924 DOI: 10.1016/j.jhsa.2012.04.038] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 04/26/2012] [Accepted: 04/27/2012] [Indexed: 02/02/2023]
Abstract
PURPOSE Exogenously administered mesenchymal stem cells and bioactive molecules are known to enhance tendon healing. Biomolecules have been successfully delivered using sutures that elute growth factors over time. We sought to evaluate the histologic and biomechanical effect of delivering both cells and bioactive substrates on a suture delivery vehicle in comparison with sutures coated with bioactive substrates alone. METHODS Bone marrow-derived stem cells were harvested from Sprague-Dawley rat femurs. Experimental cell and substrate-coated, coated suture (CS) group sutures were precoated with intercellular cell adhesion molecule 1 and poly-L-lysine and seeded with labeled bone marrow-derived stem cells. Control (substrate-only [SO] coated) group sutures were coated with intercellular cell adhesion molecule 1 and poly-L-lysine only. Using a matched-paired design, bilateral Sprague-Dawley rat Achilles tendons (n = 105 rats) were transected and randomized to CS or SO repairs. Tendons were harvested at 4, 7, 10, 14, and 28 days and subjected to histologic and mechanical assessment. RESULTS Labeled cells were present at repair sites at all time points. The CS suture repairs displayed statistically greater strength compared to SO repairs at 7 days (12.6 ± 5.0 N vs 8.6 ± 3.7 N, respectively) and 10 days (21.2 ± 4.9 N vs 16.4 ± 4.8 N, respectively). There was no significant difference between the strength of CS suture repairs compared with SO repairs at 4 days (8.1 ± 5.1 N vs 6.6 ± 2.3 N, respectively), 14 days (22.8 ± 7.3 N vs 25.1 ± 9.7 N, respectively), and 28 days (40.9 ± 12.4 N vs 34.6 ± 15.0 N, respectively). CONCLUSIONS Bioactive CS sutures enhanced repair strength at 7 to 10 days. There was no significant effect at later stages. CLINICAL RELEVANCE The strength nadir of a tendon repair occurs in the first 2 weeks after surgery. Bioactive suture repair might provide a clinical advantage by jump-starting the repair process during this strength nadir. Improved early strength might, in turn allow earlier unprotected mobilization.
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Affiliation(s)
- Jeffrey Yao
- Department of Orthopaedic Surgery, Stanford University Medical Center, Palo Alto, CA, USA.
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11
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Curzi D, Salucci S, Marini M, Esposito F, Agnello L, Veicsteinas A, Burattini S, Falcieri E. How physical exercise changes rat myotendinous junctions: an ultrastructural study. Eur J Histochem 2012; 56:e19. [PMID: 22688300 DOI: 10.4081/ejh.2012.19] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 02/16/2012] [Accepted: 03/02/2012] [Indexed: 11/23/2022] Open
Abstract
Myotendinous junctions can be easily injured by overloading or trauma, and exercise training may be a way of increasing their resistance to mechanical stress. To this end, we examined herein the morphological changes induced by moderate exercise training in the myotendinous junctions of extensor digitorum longus and gastrocnemius muscles in rats. Twelve Sprague-Dawley rats were used in this investigation. Six of them were trained to run on a treadmill for 1 h/day, 3 days/week over 10 weeks in order for them to achieve a running rate of 25 m/min at the end of the training period. Six age-matched sedentary rats were used as controls. The rats were sacrificed 24 h after the final training session, and the extensor digitorum longum (EDL) and the gastrocnemium were excised; the myotendinous junctions (MTJ) were then prepared and observed with electron microscopy. Digitation branching was evaluated by counting the bifurcations in the MTJ protrusions. Our observations indicate that exercise does indeed induce changes in MTJ morphology. In both muscles the number of bifurcated interdigitations increased significantly, as well as, in gastrocnemius, the branching of the finger-like processes. It was demonstrated that the MTJ is able to adapt to an increase in tensile force by enlarging the muscle-tendon contact area and, consequently, mechanical resistance.
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Affiliation(s)
- D Curzi
- DiSTeVA, University of Urbino Carlo Bò, Italy
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12
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13
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Itoigawa Y, Kishimoto KN, Okuno H, Sano H, Kaneko K, Itoi E. Hypoxia induces adipogenic differentitation of myoblastic cell lines. Biochem Biophys Res Commun 2010; 399:721-6. [PMID: 20692234 DOI: 10.1016/j.bbrc.2010.08.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 08/03/2010] [Indexed: 02/02/2023]
Abstract
Muscle atrophy usually accompanies fat accumulation in the muscle. In such atrophic conditions as back muscles of kyphotic spine and the rotator cuff muscles with torn tendons, blood flow might be diminished. It is known that hypoxia causes trans-differentiation of mesenchymal stem cells derived from bone marrow into adipocytes. However, it has not been elucidated yet if hypoxia turned myoblasts into adipocytes. We investigated adipogenesis in C2C12 and G8 murine myogenic cell line treated by hypoxia. Cells were also treated with the cocktail of insulin, dexamethasone and IBMX (MDI), which has been known to inhibit Wnt signaling and promote adipogenesis. Adipogenic differentiation was seen in both hypoxia and MDI. Adipogenic marker gene expression was assessed in C2C12. CCAAT/enhancer-binding protein (C/EBP) beta, alpha and peroxisome proliferator activating receptor (PPAR) gamma were increased by both hypoxia and MDI. The expression profile of Wnt10b was different between hypoxia and MDI. The mechanism for adipogenesis of myoblasts in hypoxia might be regulated by different mechanism than the modification of Wnt signaling.
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14
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Abstract
Noninsertional Achilles tendinitis is a distinct clinical entity, frequently characterized by swelling, pain, and lower limb dysfunction. This condition can be frustrating to treat, for the patient and the physician alike, as reflected in the various treatments, both conservative and surgical, that have been described. Although many patients with Achilles tendinitis can be successfully treated with nonoperative methods, persistent symptoms require surgical treatment, such as tenotomy, debridement, or repair.
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Affiliation(s)
- G Andrew Murphy
- Department of Orthopaedic Surgery, Campbell Clinic, University of Tennessee, Memphis, Tennessee, 1211 Union Avenue, Suite 510, Memphis, TN 38104, USA.
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15
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Grosset JF, Onambele-Pearson G. Effect of foot and ankle immobilization on leg and thigh muscles' volume and morphology: a case study using magnetic resonance imaging. Anat Rec (Hoboken) 2009; 291:1673-83. [PMID: 18951503 DOI: 10.1002/ar.20759] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Our aim was to determine the time course of any changes in muscle volume and shape in the lower limbs following immobilization. A healthy young woman (29 years) had suffered a fracture of the fifth metatarsal of the right foot. MRI scanning of her right thigh and calf muscles had been performed 1 month before the injury (Pre) during a scan initially planned as a teaching tool, 2 days following a 4-week immobilization period (Post), and after a 2-month recovery period (Post+2). The results show muscle volume decrements in the triceps surae (TS), quadriceps (Quad), and hamstring (Ham) of 21.9%, 24.1%, and 6.5%, respectively, between the Pre and Post measurements. At Post+2, the Quad and TS muscle volumes were still 5.2% and 9.5% lower, compared with the Pre data. The Ham muscle volume, however, was 2.7% greater than at the Pre phase. Following recovery, the increase in individual TS muscles volume was limited to both proximal and medial (with respect to the knee joint) segments of the muscles. These results indicate very substantial and rapid losses in muscle volumes, both proximally and distally to the immobilization site. The results also show that recovery is far from complete up to 2 months post cast removal. The results have implications for the requirements for rehabilitation for orthopedic patients.
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Affiliation(s)
- Jean-François Grosset
- Department of Exercise and Sport Sciences, Manchester Metropolitan University, Alsager ST7 2HL, UK.
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16
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Kojima H, Sakuma E, Mabuchi Y, Mizutani J, Horiuchi O, Wada I, Horiba M, Yamashita Y, Herbert DC, Soji T, Otsuka T. Ultrastructural changes at the myotendinous junction induced by exercise. J Orthop Sci 2008; 13:233-9. [PMID: 18528657 DOI: 10.1007/s00776-008-1211-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Accepted: 01/18/2008] [Indexed: 10/22/2022]
Abstract
BACKGROUND Although exercise is believed to reduce the risk of rupture of the myotendinous junction, exercise-induced structural changes in this region have not been studied. We examined exercise-induced ultrastructural changes in the myotendinous junction of the lower legs in rats. METHODS Ten adult male LETO rats were used. Five rats were randomly placed in the Exercise group; the remaining five were used as controls and placed in the non-Exercise group. Running exercise was performed every day for 4 weeks. The tibialis anterior and gastrocnemius muscles were then removed from both legs from each animal in the two groups. The specimens were subsequently examined by transmission electron microscopy (TEM). Numerous finger-like processes were observed at the myotendinous junction. The changes in frequency of branching of the finger-like process (the number of times one finger-like process branched) and the direction of the processes (the angle of the major axis of a finger-like process to the longitudinal direction of the muscle fiber) were studied. To evaluate the two indicators above, each 10 fingerlike process was randomly and separately selected from the tibialis anterior and gastrocnemius muscles of rats, providing 50 finger-like processes of both muscles for evaluation per group. RESULTS In terms of the frequency of branching of the fingerlike processes, the mean values obtained in the non-Exercise group were 0.04 and 0.18 times, respectively, in the tibialis anterior and gastrocnemius muscles and were 0.38 and 1.16 times, respectively, in these two muscles in the Exercise group. Regarding the direction of the finger-like processes, the values were 4.1 degrees and 3.6 degrees, respectively in the non-Exercise group and 10.4 degrees and 14.5 degrees , respectively in the Exercise group. The differences between the two animal groups were significant. CONCLUSIONS Morphological changes in the myotendinous junction occurred as an adaptation to tension increased by exercise.
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Affiliation(s)
- Hiroshi Kojima
- Department of Musculoskeletal Medicine, Nagoya City University Medical School, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi, Japan
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17
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Abstract
Tendon disorders are commonly seen in clinical practice. Their successful treatment is difficult and patients often experience symptoms for prolonged periods of time. At present the aetiology of tendon disorders remains unclear, with several factors having been implicated. An improved understanding of tendon injury and healing is essential to enable focused treatment strategies to be devised.
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Affiliation(s)
- P Sharma
- Salisbury District Hospital, Wessex Deanery, UK
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18
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Abstract
Spastic paresis follows chronic disruption of the central execution of volitional command. Motor function in patients with spastic paresis is subjected over time to three fundamental insults, of which the last two are avoidable: (1) the neural insult itself, which causes paresis, i.e., reduced voluntary motor unit recruitment; (2) the relative immobilization of the paretic body part, commonly imposed by the current care environment, which causes adaptive shortening of the muscles left in a shortened position and joint contracture; and (3) the chronic disuse of the paretic body part, which is typically self-imposed in most patients. Chronic disuse causes plastic rearrangements in the higher centers that further reduce the ability to voluntarily recruit motor units, i.e., that aggravate baseline paresis. Part I of this review focuses on the pathophysiology of the first two factors causing motor impairment in spastic paresis: the vicious cycle of paresis-disuse-paresis and the contracture in soft tissues.
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Affiliation(s)
- Jean-Michel Gracies
- Department of Neurology, Mount Sinai Medical Center, One Gustave L Levy Place, Annenberg 2/Box 1052, New York, New York 10029-6574, USA.
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19
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Abstract
Because most Achilles tendon injuries take place in sports and there has been a general increase in the popularity of sporting activities, the number and incidence of Achilles tendon overuse injuries have increased in the industrialized countries during the last few decades. The term "Achilles paratendinopathy" is used in clinical practice to describe activity-related Achilles pain combined with tenderness on palpation, providing that there is no suspicion of intratendinous pathology on the basis of patient history, clinical examination, or imaging examinations. This article discusses Achilles paratendinopathy.
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Affiliation(s)
- Mika Paavola
- Department of Orthopaedics and Traumatology, Helsinki University Central Hospital, Töölö Hospital, Helsinki, Finland.
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20
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See EKN, Ng GYF, Ng COY, Fung DTC. Running exercises improve the strength of a partially ruptured Achilles tendon. Br J Sports Med 2005; 38:597-600. [PMID: 15388547 PMCID: PMC1724906 DOI: 10.1136/bjsm.2003.007120] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVES To examine the effects of running and swimming exercises on the functional performance and mechanical strength of a recovering Achilles tendon. METHODS 30 Sprague-Dawley rats had surgical transection of their right medial Achilles tendon. The rats were divided into running (n = 11), swimming (n = 10), and control (n = 9) groups. The running and swimming groups were given daily exercise training, starting from the fifth day after the injury; the control group did not exercise throughout the period of the experiment. An Achilles functional index (AFI) was recorded before the operation and on the third, 10th, and 30th days after the operation. On the 30th day, the rats were killed and their Achilles tendons harvested for biomechanical testing of load relaxation properties, stiffness, and ultimate tensile strength (UTS). The AFI data were analysed by two way analysis of variance; load relaxation, stiffness, and UTS data were analysed by multivariate analysis, with alpha at 0.05. RESULTS The UTS of the running group was higher than in the control group (p = 0.015), while there was no significant difference between the swimming and control groups (p = 0.228). Differences in stiffness and load relaxation were non-significant (p = 0.823 and 0.633, respectively). The AFI results did not differ among the three groups (p = 0.242). CONCLUSIONS Running exercises can improve the strength of partially ruptured Achilles tendons at 30 days after injury.
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Affiliation(s)
- E K N See
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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21
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Abstract
Tendon disorders are frequent and are responsible for substantial morbidity both in sports and in the workplace. Tendinopathy, as opposed to tendinitis or tendinosis, is the best generic descriptive term for the clinical conditions in and around tendons arising from overuse. Tendinopathy is a difficult problem requiring lengthy management, and patients often respond poorly to treatment. Preexisting degeneration has been implicated as a risk factor for acute tendon rupture. Several physical modalities have been developed to treat tendinopathy. There is limited and mixed high-level evidence to support the, albeit common, clinical use of these modalities. Further research and scientific evaluation are required before biological solutions become realistic options.
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Affiliation(s)
- Pankaj Sharma
- Department of Trauma and Orthopaedics, Keele University School of Medicine, Thornburrow Drive, Hartshill, Stoke-on-Trent, Staffordshire, ST4 7QB, United Kingdom
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22
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Järvinen TAH, Józsa L, Kannus P, Järvinen TLN, Järvinen M. Organization and distribution of intramuscular connective tissue in normal and immobilized skeletal muscles. An immunohistochemical, polarization and scanning electron microscopic study. J Muscle Res Cell Motil 2003; 23:245-54. [PMID: 12500904 DOI: 10.1023/a:1020904518336] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Collagen fiber network is a major contributor to the coherence and tensile strength of normal skeletal muscle. Despite the well-recognized importance of the intramuscular connective tissue to the normal integrity and function of the skeletal muscle, the specific architecture including the location and three-dimensional orientation of the intramuscular connective tissue within the muscle tissue is poorly described. The structure of the intramuscular connective tissue was studied by immunohistochemistry, polarization microscopy (the crimp length and angle of the collagen fibers) and scanning electron microscope (SEM) in rat skeletal muscles (gastrocnemius, soleus and tibialis anterior) in normal situation and after 3 weeks of disuse (immobilization). Three separate networks of collagen fibers were distinguished by SEM in the normal endomysium; fibers running longitudinally on the surface of the muscle fibers (the main collagen orientation), fibers running perpendicularly to the long axis of the muscle fibers and having contacts with adjacent muscle fibers, and fibers attached to the intramuscular nerves and arteries. Similarly, the SEM analysis also disclosed three distinct collagen fiber networks running in different directions in the perimysium, but, contrary to the endomysium, the main fiber orientation could not be established. Immobilization resulted in a marked increase in the endo- and perimysial connective tissue, the majority of the increased endomysial collagen being deposited directly on the sarcolemma of the muscle cells. Immobilization also resulted in substantial increase in the number of perpendicularly oriented collagen fibers with contacts to two adjacent muscle fibers in the endomysium. Further, immobilization clearly disturbed the normal structure of the endomysium making it impossible to distinguish the various networks of fibers from each other. In the perimysium, immobilization-induced changes were similar, the number of longitudinally oriented collagen fibers was increased, the connective tissue was very dense, the number of irregularly oriented collagen fibers was markedly increased, and consequently, the different networks of collagen fibers could not be distinguished from each other. Of the three studied intact muscles, the crimp angle of the collagen fibers was lowest in the soleus and highest in the gastrocnemius muscle, and the crimp angle decreased over 10% in all muscles after the immobilization-period. Altogether, the above described quantitative and qualitative changes in the intramuscular connective tissue are likely to contribute to the deteriorated function and biomechanical properties of the immobilized skeletal muscle.
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Affiliation(s)
- Tero A H Järvinen
- Department of Surgery, Institute of Medical Technology, University of Tampere and Tampere University Hospital, Tampere, Finland.
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23
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Affiliation(s)
- Mika Paavola
- Department of Surgery, Tampere University Hospital and Medical School, University of Tampere, PO Box 2000, FIN-33521, Tampere, Finland.
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24
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Ballara SC, Miotla JM, Paleolog EM. New vessels, new approaches: angiogenesis as a therapeutic target in musculoskeletal disorders. Int J Exp Pathol 1999; 80:235-50. [PMID: 10607014 PMCID: PMC2517830 DOI: 10.1046/j.1365-2613.1999.00129.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Musculoskeletal disorders such as rheumatoid arthritis (RA) and osteoarthritis are a common cause of pain and disability. The vasculature is an important component of the musculoskeletal system, and vascularization is a key event in the development of normal cartilage and bone. By promoting the delivery of nutrients, oxygen and cells, blood vessels help maintain the structural and functional integrity of joints and soft tissue and may facilitate tissue repair and healing. The identification of pro-angiogenic mediators such as vascular endothelial growth factor (VEGF) has led to the development of antiangiogenic therapies for the treatment of neoplastic diseases. The important role of angiogenesis, and especially VEGF, in the pathogenesis of joint disorders such as RA suggests that antiangiogenic therapy may be a useful adjunct to existing approaches in RA.
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Affiliation(s)
- S C Ballara
- Kennedy Institute of Rheumatology, London, United Kingdom
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25
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Tyml K, Mathieu-Costello O, Cheng L, Noble EG. Differential microvascular response to disuse in rat hindlimb skeletal muscles. J Appl Physiol (1985) 1999; 87:1496-505. [PMID: 10517784 DOI: 10.1152/jappl.1999.87.4.1496] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of the study was to address discrepant findings in the literature regarding coupling between decreased functional demand during disuse and reduced capillarity. We previously reported [K. Tyml, O. Mathieu-Costello, and E. Noble. Microvasc. Res. 49: 17-32, 1995] that severe disuse of rat extensor digitorum longus (EDL) muscle caused by a 2-wk application of tetrodotoxin (TTX) on the sciatic nerve is not accompanied by capillary loss. Using the same animal model, the present study examined whether this absence of coupling could be explained in terms of 1) too short a duration of disuse and 2) muscle-specific response to disuse. Fischer 344 rats were exposed to either no treatment (control) or to 2- or 8-wk TTX applications. Fiber size, capillary density per fiber cross-sectional area, and capillary-to-fiber (C/F) ratio were determined by morphometry in the EDL muscle (control, 2- and 8-wk groups) and in the superficial portion of medial gastrocnemius (Gas) muscle (control, 2 wk). In both muscles, microvascular blood flow was evaluated by intravital microscopy [red blood cell velocity in capillaries (V(RBC))] and by laser Doppler flowmetry (LDF). Regardless of duration of TTX application or muscle type, TTX-induced disuse resulted in a significant reduction of fiber area (44-71%). However, capillary density increased in EDL muscle (both at 2 and 8 wk) but not in Gas muscle. C/F ratio decreased in EDL muscle at 8 wk (18%) and in Gas muscle (39%). This indicates that the effect on capillarity depended on duration of disuse and on muscle type. V(RBC) and LDF signal were significantly larger in EDL than in Gas muscle. Analysis of change in capillarity vs. V(RBC) suggested that the outcome of disuse may be modulated by blood flow. We conclude that the duration of skeletal muscle disuse per se does not dictate capillary loss, and we hypothesize that discrepant findings of coupling between functional demand and capillarity could be due to the presence/absence of flow-related angiogenesis superimposed on the capillary removal process during disuse.
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Affiliation(s)
- K Tyml
- A. C. Burton Vascular Biology Laboratory, London Health Sciences Research, and Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada N6A 5C1.
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Kannus P, Jozsa L, Kvist M, Järvinen T, Järvinen M. Effects of immobilization and subsequent low- and high-intensity exercise on morphology of rat calf muscles. Scand J Med Sci Sports 1998; 8:160-71. [PMID: 9659677 DOI: 10.1111/j.1600-0838.1998.tb00187.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
After a cast immobilization of 3 weeks, the effects of 4-week remobilization by free cage activity or treadmill running on the morphology of the rat soleus and gastrocnemius muscles were studied. The studied morphometric parameters were: percentage volume of intramuscular connective tissue, capillary density, muscle fiber size, number of fibers with a pathological structural alteration, and fiber type distribution. In both muscles, immobilization of 3 weeks produced a significant increase in the connective tissue volume and number of fibers with pathological alterations, with a similar decrease in the capillary number and fiber size. At the same time, the relative amount of type I fibers decreased and type IIA fibers increased. Free remobilization and especially intensified remobilization by treadmill running significantly restored these values towards controls. These findings indicate that in rat soleus and gastrocnemius muscles immobilization-induced accumulation of intramuscular connective tissue, capillary loss, reduction in fiber size, accumulation of fibers with pathological structural alterations, and changes in fiber type distribution are to a great extent reversible phenomena, especially if remobilization is intensified by physical training. In clinical practice, this suggests that in patients with musculoskeletal injuries the postimmobilization rehabilitation should be early and effective.
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Affiliation(s)
- P Kannus
- Accident & Trauma Research Center, UKK-Institute, Tampere, Finland
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27
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Kannus P, Jozsa L, Järvinen TL, Kvist M, Vieno T, Järvinen TA, Natri A, Järvinen M. Free mobilization and low- to high-intensity exercise in immobilization-induced muscle atrophy. J Appl Physiol (1985) 1998; 84:1418-24. [PMID: 9516212 DOI: 10.1152/jappl.1998.84.4.1418] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
After 3 wk of immobilization, the effects of free cage activity and low- and high-intensity treadmill running (8 wk) on the morphology and histochemistry of the soleus and gastrocnemius muscles in male Sprague-Dawley rats were investigated. In both muscles, immobilization produced a significant (P < 0.001) increase in the mean percent area of intramuscular connective tissue (soleus: 18.9% in immobilized left hindlimb vs. 3.6% in nonimmobilized right hindlimb) and in the relative number of muscle fibers with pathological alterations (soleus: 66% in immobilized hindlimb vs. 6% in control), with a simultaneous significant (P < 0.001) decrease in the intramuscular capillary density (soleus: mean capillary density in the immobilized hindlimb only 63% of that in the nonimmobilized hindlimb) and muscle fiber size (soleus type I fibers: mean fiber size in the immobilized hindlimb only 69% of that in the nonimmobilized hindlimb). Many of these changes could not be corrected by free remobilization, whereas low- and high-intensity treadmill running clearly restored the changes toward control levels, the effect being most complete in the high-intensity running group. Collectively, these findings indicate that immobilization-induced pathological structural and histochemical alterations in rat calf muscles are, to a great extent, reversible phenomena if remobilization is intensified by physical training. In this respect, high-intensity exercise seems more beneficial than low-intensity exercise.
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Affiliation(s)
- P Kannus
- Accident and Trauma Research Center and Research Center of Sports Medicine, The President Urho Kekkonen Institute for Health Promotion Research, FIN-33500 Tampere, Finland.
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