Bone marrow mesenchymal stem cell­derived exosomes: A novel therapeutic agent for tendon­bone healing (Review).

In sports medicine, injuries related to the insertion of tendons into bones, including rotator cuff injuries, anterior cruciate ligament injuries and Achilles tendon ruptures, are commonly observed. However, traditional therapies have proven to be insufficient in achieving satisfactory outcomes due to the intricate anatomical structure associated with these injuries. Adult bone marrow mesenchymal stem cells possess self­renewal and multi­directional differentiation potential and can generate various mesenchymal tissues to aid in the recovery of bone, cartilage, adipose tissue and bone marrow hematopoietic tissue. In addition, extracellular vesicles derived from bone marrow mesenchymal stem cells known as exosomes, contain lipids, proteins and nucleic acids that govern the tissue microenvironment, facilitate tissue repair and perform various biological functions. Studies have demonstrated that bone marrow mesenchymal stem cell­derived exosomes can function as natural nanocapsules for drug delivery and can enhance tendon­bone healing strength. The present review discusses the latest research results on the role of exosomes released by bone marrow mesenchymal stem cells in tendon­bone healing and provides valuable information for implementing these techniques in regenerative medicine and sports health.

A new tool in percutaneous anterior odontoid screw fixation.

BACKGROUND: Percutaneous anterior odontoid screw fixation for odontoid fractures remains challenging due to the complex anatomy of the craniocervical junction. We designed a new guide instrument to help with the placement of guide wire, which have achieved satisfying surgical results. The objective of this study is to evaluate the safety and efficacy of this new tool in percutaneous anterior odontoid screw fixation. METHODS: Twenty-nine patients with odontoid fracture were retrospectively evaluated. All patients underwent percutaneous anterior odontoid screw fixation with the traditional guide instrument (n = 13) or the new guide instrument we designed (n = 16). The following clinical outcomes were compared between the two groups: operation time, radiograph times, incision length, blood loss, postoperative hospitalization, postoperative complications, bony union, fixation failure, and reoperation. Radiographs or CT scans were performed at 3, 6 and 12 months after surgery. RESULTS: There were no significant differences in preoperative demographic data between the two groups. The operation time (56.62 ± 8.32 Vs 49.63 ± 7.47, P = 0.025) and radiograph times (26.54 ± 6.94 Vs 20.50 ± 5.02, P = 0.011) of the designed guide instrument group were significantly lower than those of the traditional guide instrument group. There were no significant differences in incision length (16.08 ± 3.07 Vs 15.69 ± 2.73, P = 0.720), blood loss (16.08 ± 4.96 Vs 17.88 ± 5.98, P = 0.393), postoperative hospitalization (7.15 ± 1.91 Vs 6.88 ± 2.36, P = 0.734), postoperative complications (7.7% Vs 12.5%, P = 1), and bony union (92.3% Vs 93.8%, P = 1) between the two groups. No fixation failure or reoperation occurred in either group. CONCLUSIONS: The top of our designed guide instrument is a wedge-shaped tip with 30° inclination, which has a large contact area with the anterior surface of the cervical vertebra. According to our retrospective study, the guide instrument can reduce the operation time and radiograph times. It has potential clinical value, which needs further testing with a higher level of research design.

Efficacy and Safety of Early Tracheotomy in Acute Cervical Spinal Cord Injury.

OBJECTIVE: To evaluate the clinical efficacy and safety of early tracheotomy versus delayed tracheotomy for patients with cervical spinal cord injury. STUDY DESIGN: A descriptive study. PLACE AND DURATION OF STUDY: Department of Orthopedic Surgery, The 80th Army Hospital of PLA, Weifang, Shandong, China, from January 2012 to June 2019. METHODOLOGY: Data of 45 patients with cervical spinal cord injury, who underwent tracheotomy and cervical spine internal fixation at the study place, were retrospectively analysed. Twenty-five patients underwent tracheotomy immediately after cervical spine internal fixation (early tracheotomy group) and 20 patients underwent tracheotomy 3-12 days after cervical spine internal fixation (delayed tracheotomy group). Clinical outcomes and tracheotomy complications were compared between the two groups. RESULTS: Compared with the delayed tracheotomy, the early tracheotomy significantly reduced the total duration of mechanical ventilation (p <0.01), duration of mechanical ventilation after tracheotomy (p <0.05), duration of indwelling tracheal tube (p <0.05), and hospital stay (p <0.01). There were no significant differences in pneumonia, mortality, and complications related to tracheotomy between the groups. No incision infection for tracheotomy and cervical spine internal fixation were found in all patients. CONCLUSION: Compared with delayed tracheotomy, early tracheotomy can significantly reduce the duration of mechanical ventilation, duration of indwelling tracheal tube, and hospital stay. Early tracheotomy did not increase the risk of infection of the cervical spine internal fixation. Therefore, early tracheotomy was beneficial and safe for patients. Key Words: Spinal cord injuries, Tracheotomy, Complications.

Desumoylation of aggrecan and collagen II facilitates degradation via aggrecanases in IL-1ß-mediated osteoarthritis.

Background: Aggrecan plays a crucial role in the ability of tissues to withstand compressive loads during the pathological progression of osteoarthritis (OA). Progressive loss of aggrecan from cartilage may result in exposure of the collagen matrix and can lead to its disintegration by metalloproteases. Although aggrecanases are expressed constitutively in human chondrocytes, the degradation of aggrecan is induced by proinflammatory cytokines; however, little is known about the underlying mechanisms. Methods: Human primary chondrocytes from OA patients or healthy donors and human chondrogenic SW1353 cells were cultured and stimulated with IL-1ß in vitro, the mRNA expressions and protein levels of MMP-13, ADAMTS-4, ADAMTS-5, SENP1, and SENP2 were determined using real time PCR and Western blot, respectively. The localizations of aggrecan and Col-II, as well as the SUMOylation modification of these proteins were analyzed using immunofluorescence and immunoprecipitation assays, respectively. Results: Our results showed that a proinflammatory cytokine interleukin-1ß induced the OA model and desumoylation of aggrecan and collagen type II because the small ubiquitin-like modifier 2/3 (SUMO2/3) was co-localized with aggrecan and collagen type II proteins and interacted physically with them. Mechanistic studies have shown that knockdown of SUMO2/3 expression can significantly enhance the rate of degradation of aggrecan and collagen type II at both the mRNA and protein levels in the OA model. In addition, SUMO-specific protease 2 (SENP2) plays important roles in the desumoylation of aggrecan, while knockdown of SENP2 can protect aggrecan and collagen type II. Clinical assays have shown that OA patients have higher SENP2 levels than healthy controls, and the SENP2 level correlates negatively with both aggrecan and collagen type II levels. Conclusion: SENP2 desumoylates aggrecan and collagen type II proteins in the inflammation induced OA, and SENP2 expression correlates with OA progression.