Mesenchymal stem cell-derived exosomes: therapeutic implications for rotator cuff injury

Clinical effects of sodium hyaluronate combined with platelet-rich plasma injection on rotator cuff injury in arthroscopic repair

Objective

Rotator cuff injury is one prevalent shoulder condition that often leads to pain and dysfunction. The study explored the clinical effects of sodium hyaluronate combined with platelet-rich plasma (PRP) injection on rotator cuff injury in arthroscopic repair.

Methods

A total of 92 cases with rotator cuff injury were randomly divided into the control group (n = 46, treated with shoulder arthroscopy repair combined with subacromial space injection of sodium hyaluronate) and the experimental group (n = 46, treated with subacromial space injection of autologous PRP on the basis of the treatment in the control group). Visual analogue scale (VAS), Constant-Murley scale (CMS), University of California, Los Angeles (UCLA), American Shoulder and Elbow Society (ASES), and quality of life (QOL) scores, as well as complications were compared in the two groups before surgery and at 3 and 6 months after surgery. Shoulder range of motion (ROM) was measured before and after surgery.

Results

VAS scores of patients in the two groups at 3 and 6 months after surgery were lower than those before surgery, and the VAS scores of patients in the experimental group at 3 and 6 months after surgery were much lower than those in the control group (all P < 0.05). The scores of CMS, UCLA, ASES, and QOL, and shoulder ROM in both groups at 3 and 6 months after surgery were higher than those before surgery, and these shoulder joint function scores, QOL and shoulder ROM in the experimental group at 3 and 6 months after surgery were higher than those in the control group (all P < 0.05). No statistically significant difference presented in the incidence of complications between the two groups (P > 0.05).

Conclusion

Arthroscopic rotator cuff repair and sodium hyaluronate combined with PRP injection can effectively reduce pain symptoms, improve shoulder joint function and shoulder ROM, and improve QOL in patients with rotator cuff injury.

Exosomes Derived From Kartogenin-Preconditioned Mesenchymal Stem Cells Promote Cartilage Formation and Collagen Maturation for Enthesis Regeneration in a Rat Model of Chronic Rotator Cuff Tear

BACKGROUND

Poor tendon-to-bone healing in chronic rotator cuff tears (RCTs) is related to unsatisfactory outcomes. Exosomes derived from mesenchymal stem cells reportedly enhance rotator cuff healing. However, the difficulty in producing exosomes with a stronger effect on enthesis regeneration must be resolved.

PURPOSE

To study the effect of exosomes derived from kartogenin (KGN)-preconditioned human bone marrow mesenchymal stem cells (KGN-Exos) on tendon-to-bone healing in a rat model of chronic RCT.

STUDY DESIGN

Controlled laboratory study.

METHODS

Exosome-loaded sodium alginate hydrogel (SAH) was prepared. Moreover, exosomes were labeled with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindotricarbocyanine iodide (DiR) or 1,1'-dioctadecyl-3,3,3'3'-tetramethylindocarbocyanine perchlorate (Dil) for in vivo tracking. Bilateral rotator cuff repair (RCR) was conducted in an established chronic RCT rat model. A total of 66 rats were randomized to control, untreated exosome (un-Exos), and KGN-Exos groups to receive local injections of pure SAH, un-Exos, or KGN-Exos SAH at the repaired site. The presence of DiR/Dil-labeled exosomes was assessed at 1 day and 1 week, and tendon-to-bone healing was evaluated histologically, immunohistochemically, and biomechanically at 4 and 8 weeks.

RESULTS

Both un-Exos and KGN-Exos exhibited sustained release from SAH for up to 96 hours. In vivo study revealed that un-Exos and KGN-Exos were localized to the repaired site at 1 week. Moreover, the KGN-Exos group showed a higher histological score and increased glycosaminoglycan and collagen II expression at 4 and 8 weeks. In addition, more mature and better-organized collagen fibers with higher ratios of collagen I to collagen III were observed at 8 weeks in the tendon-to-bone interface compared with those in the control and un-Exos groups. Biomechanically, the KGN-Exos group had the highest failure load (28.12 ± 2.40 N) and stiffness (28.57 ± 2.49 N/mm) among the 3 groups at 8 weeks.

CONCLUSION

Local injection of SAH with sustained KGN-Exos release could effectively promote cartilage formation as well as collagen maturation and organization for enthesis regeneration, contributing to enhanced biomechanical properties after RCR.

CLINICAL RELEVANCE

KGN-Exos injection may be used as a cell-free therapeutic option to accelerate tendon-to-bone healing in chronic RCT.

Effect of Arthroscopic Acromioplasty Combined with Rotator Cuff Repair in the Treatment of Aged Patients with Full-Thickness Rotator Cuff Tear and Rotator Cuff Injury

Full-thickness rotator cuff tear and rotator cuff injury are frequently occurring diseases and widely exist in the social population. Surgical repair is the most effective treatment for rotator cuff tears and injuries. With the continuous development of arthroscopy, more and more surgeons choose arthroscopic acromioplasty plus rotator cuff repair for the treatment of rotator cuff injury. However, previously published systematic reviews or meta-analyses still cast doubt on the efficacy of such concomitant procedures for postoperative patient function and pain recovery. In this study, we analyzed the effects of parameters such as shoulder function and acromion morphology on aged patients with full-thickness rotator cuff tear combined with rotator cuff injury treated with arthroscopic acromion plasty and rotator cuff repair. The results showed that arthroscopic acromion plasty and rotator cuff repair helped to promote the joint function recovery of the aged patients with full-thickness rotator cuff tear combined with rotator cuff injury and alleviate the pain of the patients. Compared with simple rotator cuff repair, this technique can increase the postoperative AT and reduce the ACEA and to some extent reduce the risk of postoperative rotator cuff reinjury, which is worthy of promotion.

Advances in Stem Cell Therapies for Rotator Cuff Injuries

Rotator cuff injury is a common upper extremity musculoskeletal disease that may lead to persistent pain and functional impairment. Despite the clinical outcomes of the surgical procedures being satisfactory, the repair of the rotator cuff remains problematic, such as through failure of healing, adhesion formation, and fatty infiltration. Stem cells have high proliferation, strong paracrine action, and multiple differentiation potential, which promote tendon remodeling and fibrocartilage formation and increase biomechanical strength. Additionally, stem cell-derived extracellular vesicles (EVs) can increase collagen synthesis and inhibit inflammation and adhesion formation by carrying regulatory proteins and microRNAs. Therefore, stem cell-based therapy is a promising therapeutic strategy that has great potential for rotator cuff healing. In this review, we summarize the advances of stem cells and stem cell-derived EVs in rotator cuff repair and highlight the underlying mechanism of stem cells and stem cell-derived EVs and biomaterial delivery systems. Future studies need to explore stem cell therapy in combination with cellular factors, gene therapy, and novel biomaterial delivery systems.

The Therapeutic Potential of Exosomes in Soft Tissue Repair and Regeneration

Soft tissue defects are common following trauma and tumor extirpation. These injuries can result in poor functional recovery and lead to a diminished quality of life. The healing of skin and muscle is a complex process that, at present, leads to incomplete recovery and scarring. Regenerative medicine may offer the opportunity to improve the healing process and functional outcomes. Barriers to regenerative strategies have included cost, regulatory hurdles, and the need for cell-based therapies. In recent years, exosomes, or extracellular vesicles, have gained tremendous attention in the field of soft tissue repair and regeneration. These nanosized extracellular particles (30-140 nm) can break the cellular boundaries, as well as facilitate intracellular signal delivery in various regenerative physiologic and pathologic processes. Existing studies have established the potential of exosomes in regenerating tendons, skeletal muscles, and peripheral nerves through different mechanisms, including promoting myogenesis, increasing tenocyte differentiation and enhancing neurite outgrowth, and the proliferation of Schwann cells. These exosomes can be stored for immediate use in the operating room, and can be produced cost efficiently. In this article, we critically review the current advances of exosomes in soft tissue (tendons, skeletal muscles, and peripheral nerves) healing. Additionally, new directions for clinical applications in the future will be discussed.