Extracellular Vesicles Delivered by Injectable Collagen Promote Bone–Tendon Interface Healing and Prevent Fatty Degeneration of Rotator Cuff Muscle

Published:January 15, 2022DOI:


      This study aimed (1) to confirm the maintenance of the extracellular vesicles (EVs) delivered via injectable collagen at the application site, and (2) to evaluate the effect of EVs derived from the human umbilical cord-derived mesenchymal stem cells and loaded in an injectable collagen gel after rotator cuff repair (RCR).


      Rabbits (n = 20) were assigned to normal (N), repair-only (R), and those administered with injectable collagen after repair (RC), and EV-laden injectable collagen after repair (RCE) groups. The EVs isolated by ultra-centrifugation from the human umbilical cord-derived mesenchymal stem cells spent medium were mixed with collagen and administered accordingly. After 12 weeks, the rabbits were sacrificed to evaluate the healing of the bone-to-tendon junction and the fatty degeneration of muscle. Histomorphometric scoring for bone–tendon interface, fatty infiltration (%), and biomechanical tests were performed. Separately, groups of 3 rabbits were assigned to 3 different time points to evaluate maintenance of green fluorescence-labeled EVs with injectable collagen via tracking on the bursal side of the rotator cuff (3 groups: 3 days, 2, and 4 weeks).


      The EVs delivered by injectable collagen remained until 4 weeks at the bursal side of the cuff tissue. The RCE group showed a significantly greater histomorphometric total score (P < .001, and P = .013, respectively) and significantly lower fatty degeneration than the RC and R groups (P = .001, and P = .013, respectively). The biomechanical tests revealed significant growing trends in load-to-failure and stiffness (P = .002, and P = .013, respectively), in the R, RC, RCE, and N groups.


      EVs mounted in injectable collagen remained at the repair site for at least 4 weeks after application. Furthermore, they effectively promote bone-to-tendon healing via collagen maturation in bone–tendon interface and preventing fatty degeneration of rotator muscle after RCR as compared with collagen-only or repair-only groups.

      Clinical Relevance

      The combination of collagen with EVs significantly promotes rotator cuff healing demonstrating potential clinical application during partial rotator cuff tear or after RCR.
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        • Tashjian R.Z.
        Epidemiology, natural history, and indications for treatment of rotator cuff tears.
        Clin Sports Med. 2012; 31: 589-604
        • Kluger R.
        • Bock P.
        • Mittlböck M.
        • Krampla W.
        • Engel A.
        Long-term survivorship of rotator cuff repairs using ultrasound and magnetic resonance imaging analysis.
        Am J Sports Med. 2011; 39: 2071-2081
        • Wang Z.
        • Liu X.
        • Davies M.R.
        • Horne D.
        • Kim H.
        • Feeley B.T.
        A mouse model of delayed rotator cuff repair results in persistent muscle atrophy and fatty infiltration.
        Am J Sports Med. 2018; 46: 2981-2989
        • Kaizawa Y.
        • Leyden J.
        • Behn A.W.
        • et al.
        Human tendon–derived collagen hydrogel significantly improves biomechanical properties of the tendon-bone interface in a chronic rotator cuff injury model.
        J Hand Surg Am. 2019; 44 (899.e891-899.e811)
        • Wang C.
        • Hu Q.
        • Song W.
        • Yu W.
        • He Y.
        Adipose stem cell-derived exosomes decrease fatty infiltration and enhance rotator cuff healing in a rabbit model of chronic tears.
        Am J Sports Med. 2020; 48: 1456-1464
        • Shin M.J.
        • Shim I.K.
        • Kim D.M.
        • et al.
        Engineered cell sheets for the effective delivery of adipose-derived stem cells for tendon-to-bone healing.
        Am J Sports Med. 2020; 48: 3347-3358
        • Eliasberg C.D.
        • Dar A.
        • Jensen A.R.
        • et al.
        Perivascular stem cells diminish muscle atrophy following massive rotator cuff tears in a small animal model.
        J Bone Joint Surg Am. 2017; 99: 331-341
        • Kim Y.S.
        • Sung C.H.
        • Chung S.H.
        • Kwak S.J.
        • Koh Y.G.
        Does an injection of adipose-derived mesenchymal stem cells loaded in fibrin glue influence rotator cuff repair outcomes? A clinical and magnetic resonance imaging study.
        Am J Sports Med. 2017; 45: 2010-2018
        • Thangarajah T.
        • Sanghani-Kerai A.
        • Henshaw F.
        • Lambert S.M.
        • Pendegrass C.J.
        • Blunn G.W.
        Application of a demineralized cortical bone matrix and bone marrow-derived mesenchymal stem cells in a model of chronic rotator cuff degeneration.
        Am J Sports Med. 2018; 46: 98-108
        • Liu X.N.
        • Yang C.J.
        • Kim J.E.
        • et al.
        Enhanced tendon-to-bone healing of chronic rotator cuff tears by bone marrow aspirate concentrate in a rabbit model.
        Clin Orthop Surg. 2018; 10: 99-110
        • Toh W.S.
        • Lai R.C.
        • Hui J.H.P.
        • Lim S.K.
        MSC exosome as a cell-free MSC therapy for cartilage regeneration: Implications for osteoarthritis treatment.
        Semin Cell Dev Biol. 2017; 67: 56-64
        • Cao Y.
        • Sun H.
        • Zhu H.
        • et al.
        Allogeneic cell therapy using umbilical cord MSCs on collagen scaffolds for patients with recurrent uterine adhesion: A phase I clinical trial.
        Stem Cell Res Ther. 2018; 9: 192
        • Schlegel T.F.
        • Abrams J.S.
        • Bushnell B.D.
        • Brock J.L.
        • Ho C.P.
        Radiologic and clinical evaluation of a bioabsorbable collagen implant to treat partial-thickness tears: A prospective multicenter study.
        J Shoulder Elbow Surg. 2018; 27: 242-251
        • Zhang L.
        • Fan C.
        • Hao W.
        • et al.
        NSCs migration promoted and drug delivered exosomes-collagen scaffold via a bio-specific peptide for one-step spinal cord injury repair.
        Adv Healthc Mater. 2021; e2001896
        • Uhthoff H.K.
        • Seki M.
        • Backman D.S.
        • Trudel G.
        • Himori K.
        • Sano H.
        Tensile strength of the supraspinatus after reimplantation into a bony trough: An experimental study in rabbits.
        J Shoulder Elbow Surg. 2002; 11: 504-509
        • Abdou M.A.
        • Kim G.E.
        • Kim J.
        • et al.
        How long should we wait to create the goutallier stage 2 fatty infiltrations in the rabbit shoulder for repairable rotator cuff tear model?.
        Biomed Res Int. 2019; 2019 (7387131)
        • Sun Y.
        • Kwak J.M.
        • Kholinne E.
        • et al.
        Small subchondral drill holes improve marrow stimulation of rotator cuff repair in a rabbit model of chronic rotator cuff tear.
        Am J Sports Med. 2020; 48: 706-714
        • Momen-Heravi F.
        • Balaj L.
        • Alian S.
        • et al.
        Current methods for the isolation of extracellular vesicles.
        Biol Chem. 2013; 394: 1253-1262
        • Moreira A.
        • Kahlenberg S.
        • Hornsby P.
        Therapeutic potential of mesenchymal stem cells for diabetes.
        J Mol Endocrinol. 2017; 59: R109-R120
        • Kim S.Y.
        • Phan T.H.
        • Limantoro C.
        • Kalionis B.
        • Chrzanowski W.
        Isolation and characterization of extracellular vesicles from mesenchymal stromal cells.
        in: Joglekar M.V. Hardikar A.A. Progenitor cells: Methods and protocols. Springer New York, New York, NY2019: 15-23
        • Hooker G.D.
        • Taylor B.M.
        • Driman D.K.
        Prevention of adhesion formation with use of sodium hyaluronate-based bioresorbable membrane in a rat model of ventral hernia repair with polypropylene mesh—a randomized, controlled study.
        Surgery. 1999; 125: 211-216
        • Kim Y.I.
        Comparative study for preventive effects of intra-abdominal adhesion using cyclo-oxygenase-2 enzyme (COX-2) inhibitor, low molecular weight heparin (LMWH), and synthetic barrier.
        Yonsei Med J. 2013; 54: 1491-1497
        • Chung S.W.
        • Park H.
        • Kwon J.
        • Choe G.Y.
        • Kim S.H.
        • Oh J.H.
        Effect of hypercholesterolemia on fatty infiltration and quality of tendon-to-bone healing in a rabbit model of a chronic rotator cuff tear: Electrophysiological, biomechanical, and histological analyses.
        Am J Sports Med. 2016; 44: 1153-1164
        • Lee K.W.
        • Lee J.S.
        • Kim Y.S.
        • Shim Y.B.
        • Jang J.W.
        • Lee K.I.
        Effective healing of chronic rotator cuff injury using recombinant bone morphogenetic protein-2 coated dermal patch in vivo.
        J Biomed Mater Res B Appl Biomater. 2017; 105: 1840-1846
        • Maffulli N.
        • Longo U.G.
        • Franceschi F.
        • Rabitti C.
        • Denaro V.
        Movin and Bonar scores assess the same characteristics of tendon histology.
        Clin Orthop Relat Res. 2008; 466: 1605-1611
        • Yoon J.P.
        • Chung S.W.
        • Jung J.W.
        • et al.
        Is a local administration of parathyroid hormone effective to tendon-to-bone healing in a rat rotator cuff repair model?.
        J Orthop Res. 2020; 38: 82-91
        • Kim D.M.
        • Shim I.K.
        • Shin M.J.
        • et al.
        A combination treatment of raloxifene and vitamin D enhances bone-to-tendon healing of the rotator cuff in a rat model.
        Am J Sports Med. 2020; 48: 2161-2169
        • Kuwahara Y.
        • Kishimoto K.N.
        • Itoigawa Y.
        • et al.
        Fatty degeneration and wnt10b expression in the supraspinatus muscle after surgical repair of torn rotator cuff tendon.
        J Orthop Surg (Hong Kong). 2019; 27 (2309499019864817)
        • Suh D.S.
        • Lee J.K.
        • Yoo J.C.
        • et al.
        Atelocollagen enhances the healing of rotator cuff tendon in rabbit model.
        Am J Sports Med. 2017; 45: 2019-2027
        • Chae S.H.
        • Won J.Y.
        • Yoo J.C.
        Clinical outcome of ultrasound-guided atelocollagen injection for patients with partial rotator cuff tear in an outpatient clinic: A preliminary study.
        Clin Shoulder Elbow. 2020; 23: 80-85
        • Wang C.
        • Song W.
        • Chen B.
        • Liu X.
        • He Y.
        Exosomes isolated from adipose-derived stem cells: a new cell-free approach to prevent the muscle degeneration associated with torn rotator cuffs.
        Am J Sports Med. 2019; 47: 3247-3255
        • Deniz G.
        • Kose O.
        • Tugay A.
        • Guler F.
        • Turan A.
        Fatty degeneration and atrophy of the rotator cuff muscles after arthroscopic repair: Does it improve, halt or deteriorate?.
        Arch Orthop Trauma Surg. 2014; 134: 985-990