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Zhou H, Lin X, Feng S, Zhu S, Zhou H, Chen H, Youwu H, Wang Z, Wang R, Shao X, Wang J. Metformin mitigates adipogenesis of fibro-adipogenic progenitors after rotator cuff tears via activating mTOR/ULK1-mediated autophagy. Am J Physiol Cell Physiol 2024; 326:C1590-C1603. [PMID: 38586878 DOI: 10.1152/ajpcell.00034.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/28/2024] [Accepted: 03/29/2024] [Indexed: 04/09/2024]
Abstract
Muscular fatty infiltration is a common issue after rotator cuff tears (RCTs), which impair shoulder function. Females suffer a higher prevalence and a more severe degree of muscular fatty infiltration after RCT when compared with males, with the underlying mechanisms remaining unclear. Fibro-adipogenic progenitors (FAPs) are the primary source of muscular fatty infiltration following RCT. Our findings disclose that gender-specific disparities in muscular fatty infiltration are linked to mTOR/ULK1-mediated autophagy of FAPs. Decreased autophagic activity contributes to adipogenic differentiation in female FAPs after RCT. Furthermore, metformin could enhance mTOR/ULK1-mediated autophagic processes of FAPs, thereby alleviating fatty infiltration and improving shoulder functionality after RCT. Together, our study reveals that gender differences in muscular fatty infiltration arise from distinct autophagic activities. Metformin could be a promising noninvasive intervention to ameliorate muscular fatty infiltration of RCT.NEW & NOTEWORTHY The current study demonstrated that gender-specific disparities in muscular fatty infiltration are attributed to mTOR/ULK1-mediated autophagy of FAPs. Decreased autophagic activity contributes to adipogenic differentiation in female FAPs after RCT. Moreover, metformin could enhance mTOR/ULK1-mediated autophagic processes of FAPs, thereby alleviating fatty infiltration and improving shoulder functionality after RCT. Therefore, metformin could be a promising noninvasive intervention to ameliorate muscular fatty infiltration of RCT.
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Affiliation(s)
- Hao Zhou
- Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Xingzuan Lin
- Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Shujing Feng
- Department of Sports Medicine, School of Exercise and Health, Shanghai University of Sport, Shanghai, People's Republic of China
| | - Siyuan Zhu
- Department of Hand Surgery, Huashan Hospital, Fudan University, Shanghai, People's Republic of China
| | - Han Zhou
- Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Huifang Chen
- Department of Sports Medicine, School of Exercise and Health, Shanghai University of Sport, Shanghai, People's Republic of China
| | - He Youwu
- Department of Hand Plastic Surgery, The First People's Hospital of Linping District, Hangzhou, People's Republic of China
| | - Zekai Wang
- Department of Life Science, University of Toronto, Toronto, Ontario, Canada
| | - Ru Wang
- Department of Sports Medicine, School of Exercise and Health, Shanghai University of Sport, Shanghai, People's Republic of China
| | - Xiexiang Shao
- Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Jianhua Wang
- Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
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Zhang C, Lin Y, Li H, Hu H, Chen Y, Huang Y, Huang Z, Fang X, Zhang W, Lin Y. Fatty acid binding protein 4 (FABP4) induces chondrocyte degeneration via activation of the NF-κb signaling pathway. FASEB J 2024; 38:e23347. [PMID: 38095503 DOI: 10.1096/fj.202301882r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 10/28/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023]
Abstract
The pathogenesis of osteoarthritis (OA) is still unclear. Fatty acid binding protein 4 (FABP4), a novel adipokine, has been found to play a role in OA. This study aimed to explore the role of NF-κB in FABP4-induced OA. In the in vivo study, four pairs of 12-week-old male FABP4 knockout (KO) and wild-type (WT) mice were included. The activation of NF-κB was assessed. In parallel, 24 6-week-old male C57/Bl6 mice were fed a high-fat diet (HFD) and randomly allocated to four groups: daily oral gavage with (1) PBS solution; (2) QNZ (NF-κB-specific inhibitor, 1 mg/kg/d); (3) BMS309403 (FABP4-specific inhibitor, 30 mg/kg/d); and (4) BMS309403 (30 mg/kg/d) + QNZ (1 mg/kg/d). The diet and treatment were sustained for 4 months. The knee joints were obtained to assess cartilage degradation, NF-κB activation, and subchondral bone sclerosis. In the in vitro study, a mouse chondrogenic cell line (ATDC5) was cultured. FABP4 was supplemented to stimulate chondrocytes, and the activation of NF-κB was investigated. In parallel, QNZ and NF-κB-specific siRNA were used to inhibit NF-κB. In vivo, the FABP4 WT mice had more significant NF-κB activation than the KO mice. Dual inhibition of FABP4 and NF-κB alleviated knee OA in mice. FABP4 has no significant effect on the activation of the JNK signaling pathway. In vitro, FABP4 directly activated NF-κB in chondrocytes. The use of QNZ and NF-κB-siRNA significantly alleviated the expression of catabolic markers of chondrocytes induced by FABP4. FABP4 induces chondrocyte degeneration by activating the NF-κB pathway.
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Affiliation(s)
- Chaofan Zhang
- Department of Orthopaedic Surgery, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Orthopaedic Surgery, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Fujian Provincial Institute of Orthopedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Yiming Lin
- Department of Orthopaedic Surgery, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Orthopaedic Surgery, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Fujian Provincial Institute of Orthopedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Hongyan Li
- Department of Orthopaedic Surgery, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Orthopaedic Surgery, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Fujian Provincial Institute of Orthopedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Hongxin Hu
- Department of Orthopaedic Surgery, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Orthopaedic Surgery, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Fujian Provincial Institute of Orthopedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Orthopedic Surgery, Affiliated Hospital of Putian University, Putian, China
| | - Yongfa Chen
- Department of Orthopaedic Surgery, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Orthopaedic Surgery, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Fujian Provincial Institute of Orthopedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Pediatric Orthopaedic Surgery, the First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Ying Huang
- Department of Orthopaedic Surgery, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Orthopaedic Surgery, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Fujian Provincial Institute of Orthopedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Zida Huang
- Department of Orthopaedic Surgery, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Orthopaedic Surgery, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Fujian Provincial Institute of Orthopedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Xinyu Fang
- Department of Orthopaedic Surgery, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Orthopaedic Surgery, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Fujian Provincial Institute of Orthopedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Wenming Zhang
- Department of Orthopaedic Surgery, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Orthopaedic Surgery, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Fujian Provincial Institute of Orthopedics, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Yunzhi Lin
- Department of Stomatology, the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
- Department of Stomatology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China
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Baek J, Ryu B, Kim J, Lee SG, Oh MS, Hong KS, Kim EY, Kim CY, Chung HM. Immunomodulation of Pluripotent Stem Cell-Derived Mesenchymal Stem Cells in Rotator Cuff Tears Model. Biomedicines 2022; 10:biomedicines10071549. [PMID: 35884853 PMCID: PMC9312476 DOI: 10.3390/biomedicines10071549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/20/2022] [Accepted: 06/23/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Rotator cuff tears (RCTs) induce chronic muscle weakness and shoulder pain. Treatment of RCT using surgery or drugs causes lipid infiltration and fibrosis, which hampers tissue regeneration and complete recovery. The pluripotent stem cell-derived multipotent mesenchymal stem cells (M-MSCs) represent potential candidate next-generation therapies for RCT. Methods: The difference between M-MSCs and adult-MSCs was compared and analyzed using next-generation sequencing (NGS). In addition, using a rat model of RCT, the muscle recovery ability of M-MSCs and adult-MSCs was evaluated by conducting a histological analysis and monitoring the cytokine expression level. Results: Using NGS, it was confirmed that M-MSC was suitable for transplantation because of its excellent ability to regulate inflammation that promotes tissue repair and reduced apoptosis and rejection during transplantation. In addition, while M-MSCs persisted for up to 8 weeks in vivo, they significantly reduced inflammation and adipogenesis-related cytokine levels in rat muscle. Significant differences were also confirmed in histopathological remission. Conclusions: M-MSCs remain in the body longer to modulate immune responses in RCTs and have a greater potential to improve muscle recovery by alleviating acute inflammatory responses. This indicates that M-MSCs could be used in potential next-generation RCT therapies.
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Affiliation(s)
- Jieun Baek
- Departmentof Stem Cell Biology, School of Medicine, Konkuk University, Seoul 05029, Korea; (J.B.); (S.-G.L.); (M.-S.O.)
| | - Bokyeong Ryu
- College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (B.R.); (J.K.)
- Department of Laboratory Animal Medicine, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Jin Kim
- College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (B.R.); (J.K.)
- Department of Laboratory Animal Medicine, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea
| | - Seul-Gi Lee
- Departmentof Stem Cell Biology, School of Medicine, Konkuk University, Seoul 05029, Korea; (J.B.); (S.-G.L.); (M.-S.O.)
| | - Min-Seok Oh
- Departmentof Stem Cell Biology, School of Medicine, Konkuk University, Seoul 05029, Korea; (J.B.); (S.-G.L.); (M.-S.O.)
- Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Ki-Sung Hong
- Mireacellbio Co., Ltd., Seoul 04795, Korea; (K.-S.H.); (E.-Y.K.)
| | - Eun-Young Kim
- Mireacellbio Co., Ltd., Seoul 04795, Korea; (K.-S.H.); (E.-Y.K.)
| | - C-Yoon Kim
- College of Veterinary Medicine, Konkuk University, Seoul 05029, Korea; (B.R.); (J.K.)
- Correspondence: (C.-Y.K.); (H.-M.C.); Tel.: +82-10-9140-0136 (C.-Y.K.); +82-10-7190-1926 (H.-M.C.); Fax: +82-2-455-9012 (C.-Y.K. & H.-M.C.)
| | - Hyung-Min Chung
- Departmentof Stem Cell Biology, School of Medicine, Konkuk University, Seoul 05029, Korea; (J.B.); (S.-G.L.); (M.-S.O.)
- Mireacellbio Co., Ltd., Seoul 04795, Korea; (K.-S.H.); (E.-Y.K.)
- Correspondence: (C.-Y.K.); (H.-M.C.); Tel.: +82-10-9140-0136 (C.-Y.K.); +82-10-7190-1926 (H.-M.C.); Fax: +82-2-455-9012 (C.-Y.K. & H.-M.C.)
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Lui PPY, Yung PSH. Inflammatory mechanisms linking obesity and tendinopathy. J Orthop Translat 2022; 31:80-90. [PMID: 34976728 PMCID: PMC8666605 DOI: 10.1016/j.jot.2021.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/09/2021] [Accepted: 10/10/2021] [Indexed: 12/13/2022] Open
Abstract
Chronic tendinopathy is a debilitating tendon disorder with disappointing treatment outcomes. This review focuses on the potential roles of chronic low-grade inflammation in promoting tendinopathy in obesity. A systematic literature search was performed to identify all clinical studies supporting the actions of obesity-associated inflammatory mediators in the development of tendinopathy. The mechanisms of obesity-induced chronic inflammation in adipose tissue are firstly reviewed. Common inflammatory mediators potentially linking obesity and the development of tendinopathy, and their association with mechanical overuse, are discussed, along with pre-clinical evidences and a systematic literature search on clinical studies. The potential contribution of local adipose tissues in the promotion of inflammation, pain and tendon degeneration is then discussed. The future research directions are proposed. Translational potential statement Better understanding of the roles of obesity-associated inflammatory mediators on tendons will clarify the pathophysiological drivers of tendinopathy in patients with obesity and identify possible treatment targets. Further studies on the mechanisms of obesity-induced chronic inflammation on tendon are a promising direction for the treatment of tendinopathy.
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Affiliation(s)
- Pauline Po Yee Lui
- Corresponding author. Room 74037, 5/F, Lui Che Woo Clinical Sciences Building, Prince of Wales Hospital, Department of Orthopaedics and Traumatology, The Chinese University of Hong Kong, China.
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Shirasawa H, Matsumura N, Yoda M, Okubo K, Shimoda M, Uezumi A, Matsumoto M, Nakamura M, Horiuchi K. Retinoic Acid Receptor Agonists Suppress Muscle Fatty Infiltration in Mice. Am J Sports Med 2021; 49:332-339. [PMID: 33428447 DOI: 10.1177/0363546520984122] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND The infiltration of fat tissue into skeletal muscle, a condition referred to as muscle fatty infiltration or fatty degeneration, is regarded as an irreversible event that significantly compromises the motor function of skeletal muscle. PURPOSE To investigate the effect of retinoic acid receptor (RAR) agonists in suppressing the adipogenic differentiation of fibroadipogenic progenitors (FAPs) in vitro and fatty infiltration after rotator cuff tear in mice. STUDY DESIGN Controlled laboratory study. METHODS FAPs isolated from mouse skeletal muscle were cultured in adipogenic differentiation medium in the presence or absence of an RAR agonist. At the end of cell culture, adipogenic differentiation was evaluated by gene expression analysis and oil red O staining. A mouse model of fatty infiltration-which includes the resection of the rotator cuff, removal of the humeral head, and denervation the supraspinatus muscle-was used to induce fatty infiltration in the supraspinatus muscle. The mice were orally or intramuscularly administered with an RAR agonist after the surgery. Muscle fatty infiltration was evaluated by histology and gene expression analysis. RESULTS RAR agonists effectively inhibited the adipogenic differentiation of FAPs in vitro. Oral and intramuscular administration of RAR agonists suppressed the development of muscle fatty infiltration in the mice after rotator cuff tear. In accordance, we found a significant decrease in the number of intramuscular fat cells and suppressed expression in adipogenic markers. RAR agonists also increased the expression of the transcripts for collagens; however, an accumulation of collagenous tissues was not histologically evident in the present model. CONCLUSION Muscle fatty infiltration can be alleviated by RAR agonists through suppressing the adipogenic differentiation of FAPs. The results also suggest that RAR agonists are potential therapeutic agents for treating patients who are at risk of developing muscle fatty infiltration. The consequence of the increased expression of collagen transcripts by RAR agonists needs to be clarified. CLINICAL RELEVANCE RAR agonists can be used to prevent the development of muscle fatty infiltration after rotator cuff tear. Nevertheless, further studies are mandatory in a large animal model to examine the safety and efficacy of intramuscular injection of RAR agonists.
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Affiliation(s)
- Hideyuki Shirasawa
- Department of Orthopedic Surgery, School of Medicine, Keio University, Tokyo, Japan
| | - Noboru Matsumura
- Department of Orthopedic Surgery, School of Medicine, Keio University, Tokyo, Japan
| | - Masaki Yoda
- Laboratory of Cell and Tissue Biology, School of Medicine, Keio University, Tokyo, Japan
| | - Kazumasa Okubo
- Pharmacology, Pharmaceutical Research Department, Sato Pharmaceutical Co, Ltd, Tokyo, Japan
| | - Masayuki Shimoda
- Department of Pathology, School of Medicine, Keio University, Tokyo, Japan
| | - Akiyoshi Uezumi
- Department of Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
| | - Morio Matsumoto
- Department of Orthopedic Surgery, School of Medicine, Keio University, Tokyo, Japan
| | - Masaya Nakamura
- Department of Orthopedic Surgery, School of Medicine, Keio University, Tokyo, Japan
| | - Keisuke Horiuchi
- Department of Orthopedic Surgery, School of Medicine, Keio University, Tokyo, Japan.,Department of Orthopedic Surgery, National Defense Medical College, Saitama, Japan
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Ki SY, Lee YS, Kim JY, Lho T, Chung SW. Relationship between fatty infiltration and gene expression in patients with medium rotator cuff tear. J Shoulder Elbow Surg 2021; 30:387-395. [PMID: 32603896 DOI: 10.1016/j.jse.2020.06.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 05/26/2020] [Accepted: 06/08/2020] [Indexed: 02/01/2023]
Abstract
BACKGROUND Fatty infiltration (FI) is a key prognostic factor that affects outcomes after rotator cuff repair and is radiologically evaluated using the Goutallier classification. The purpose of this study was to assess alterations in gene and protein expression according to the Goutallier classification in the supraspinatus muscle and any relationships among various gene expression profiles. METHODS Twenty-four samples of the supraspinatus muscle from 12 patients with a high FI grade (grade 3 or 4) and 12 patients with a low FI grade (grade 1 or 2) with medium-sized tears were acquired during arthroscopic surgery. Alterations in the expression of genes and proteins associated with adipogenesis, fibrosis, inflammation, and muscle atrophy were compared between the high- and low-FI groups using reverse-transcription quantitative polymerase chain reaction, Western blotting, and immunohistochemistry. RESULTS mRNA expression of not only the adipogenic genes (peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α; P < .001 and P = .020) but also the fibrosis-related gene (α-smooth muscle actin; P < .001), inflammation-related genes (interleukin [IL]-1β and tumor necrosis factor α; P = .041 and P = .039), and muscle atrophy-related genes (atrogin 1 and myostatin; P = .006 and P < .001) was higher in the high-FI group compared with that in the low-FI group. In addition, adipogenic gene expression was significantly correlated with the expression of other categories of genes (all P < .05, except atrogin 1). A correlation of gene and protein expression was observed for IL-1β (P = .027) and myostatin (P = .029). CONCLUSIONS The radiologic grading of FI was associated with the expression of various genes, including adipogenic, fibrotic, inflammatory, and atrophy-related genes, and these genes were closely correlated with each other in terms of expression. This information could be helpful in patient counseling.
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Affiliation(s)
- Se-Young Ki
- Department of Orthopedic Surgery, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - Yong-Soo Lee
- Department of Orthopedic Surgery, Konkuk University School of Medicine, Seoul, Republic of Korea; Joint Center, Barunsesang Hospital, Seongnam, Republic of Korea
| | - Ja-Yeon Kim
- Department of Orthopedic Surgery, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - Taewoo Lho
- Department of Orthopedic Surgery, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - Seok Won Chung
- Department of Orthopedic Surgery, Konkuk University School of Medicine, Seoul, Republic of Korea.
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Lee YS, Kim JY, Chung SW. Rotator cuff muscle stem cells: the double-edged sword in the skeletal muscle. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:717. [PMID: 32617337 PMCID: PMC7327348 DOI: 10.21037/atm.2020.02.32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yong-Soo Lee
- Department of Orthopedic Surgery, Konkuk University School of Medicine, Seoul, Republic of Korea.,Joint Center, Barunsesang Hospital, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Ja-Yeon Kim
- Department of Orthopedic Surgery, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - Seok Won Chung
- Department of Orthopedic Surgery, Konkuk University School of Medicine, Seoul, Republic of Korea
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Ravn MK, Ostergaard TI, Schroeder HD, Nyengaard JR, Lambertsen KL, Frich LH. Supraspinatus and deltoid muscle fiber composition in rotator cuff tear conditions. JSES Int 2020; 4:431-437. [PMID: 32939464 PMCID: PMC7479021 DOI: 10.1016/j.jseint.2020.04.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Background Rotator cuff (RC) tears are associated with RC muscle atrophy and changes in composition that are crucial to the prognosis of RC repair. The aim of this study was to characterize muscle fiber composition in the supraspinatus (SS) muscle under tear conditions. Methods Muscle biopsies were obtained from 21 patients undergoing surgery for an RC tendon tear. Biopsies were obtained from the musculotendinous junction of the SS muscle, and control biopsies were harvested from the deltoid muscle (DT). Biopsies were immunohistochemically processed for detection of type 1 (slow type) and type 2 (fast type) fibers and analyzed using unbiased, stereological principles. We counted the total numbers of type 1 and 2 muscle fibers/mm2, and fiber diameter was used to estimate muscle fiber atrophy and hypertrophy. Results We found significantly more type 2 cells/mm2 in the SS compared with the DT (P < .01). In addition, we found a significantly higher fraction of type 1 fibers than type 2 fibers in the DT (P < .01), whereas both fiber types were equally present in the SS. The diameters of SS cells were generally smaller than those of DT cells. Atrophy of especially SS type 2 fibers was also demonstrated. Fiber atrophy was more pronounced in men than women. Conclusion The changes in the composition of SS muscle cell types suggest a shift from type 1 to type 2 muscle fibers and atrophy of both type 1 and 2 fibers. This composition indicates loss of endurance and rapid fatigue of the SS muscle under RC tear conditions.
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Affiliation(s)
- Morten Kjaer Ravn
- Department of Orthopaedics, Odense University Hospital, Odense, Denmark.,The Orthopaedic Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Trine Ivarsen Ostergaard
- Department of Orthopaedics, Odense University Hospital, Odense, Denmark.,The Orthopaedic Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | | | - Jens Randel Nyengaard
- Department of Clinical Medicine - Core Centre for Molecular Morphology, Section for Stereology and Microscopy, Center for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Aarhus, Denmark
| | - Kate Lykke Lambertsen
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark.,BRIDGE - Brain Research - Inter-Disciplinary Guided Excellence, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Lars Henrik Frich
- Department of Orthopaedics, Odense University Hospital, Odense, Denmark.,The Orthopaedic Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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