Local H2 release remodels senescence microenvironment for improved repair of injured bone.

The senescence microenvironment, which causes persistent inflammation and loss of intrinsic regenerative abilities, is a main obstacle to effective tissue repair in elderly individuals. In this work, we find that local H2 supply can remodel the senescence microenvironment by anti-inflammation and anti-senescence effects in various senescent cells from skeletally mature bone. We construct a H2-releasing scaffold which can release high-dosage H2 (911 mL/g, up to 1 week) by electrospraying polyhydroxyalkanoate-encapsulated CaSi2 nanoparticles onto mesoporous bioactive glass. We demonstrate efficient remodeling of the microenvironment and enhanced repair of critical-size bone defects in an aged mouse model. Mechanistically, we reveal that local H2 release alters the microenvironment from pro-inflammation to anti-inflammation by senescent macrophages repolarization and secretome change. We also show that H2 alleviates the progression of aging/injury-superposed senescence, facilitates the recruitment of endogenous cells and the preservation of their regeneration capability, thereby creating a pro-regenerative microenvironment able to support bone defect regeneration.

NIR-photocatalytic regulation of arthritic synovial microenvironment.

Synovial microenvironment (SME) plays a vital role in the formation of synovial pannus and the induction of cartilage destruction in arthritis. In this work, a concept of the photocatalytic regulation of SME is proposed for arthritis treatment, and monodispersive hydrogen-doped titanium dioxide nanorods with a rutile single-crystal structure are developed by a full-solution method to achieve near infrared-photocatalytic generation of hydrogen molecules and simultaneous depletion of overexpressed lactic acid (LA) for realizing SME regulation in a collagen-induced mouse model of rheumatoid arthritis. Mechanistically, locally generated hydrogen molecules scavenge overexpressed reactive oxygen species to mediate the anti-inflammatory polarization of macrophages, while the simultaneous photocatalytic depletion of overexpressed LA inhibits the inflammatory/invasive phenotypes of synoviocytes and macrophages and ameliorates the abnormal proliferation of synoviocytes, thereby remarkably preventing the synovial pannus formation and cartilage destruction. The proposed catalysis-mediated SME regulation strategy will open a window to realize facile and efficient arthritis treatment.

[Effectiveness analysis of arthroscopically assisted treatment of rotator cuff injury].

OBJECTIVE: To explore the method and effectiveness of arthroscopically assisted treatment of rotator cuff injury. METHODS: Between November 2009 and March 2011, 27 patients with rotator cuff injury were treated. There were 17 males and 10 females with a mean age of 43.6 years (range, 29-66 years). The disease duration was 1 to 36 months (mean, 27 months). The location was the left shoulder in 11 cases and the right shoulder in 16 cases. Of them, 12 cases had a history of trauma and 15 cases had no obvious predisposing causes. All patients had limitation of shoulder flexion and abduction. Anteroposterior and lateral X-ray films of the shoulder and the out-let X-ray films of the supraspinous muscle were taken. According to the acromion classification of Bigliani, there were 5 cases of type I, 13 cases of type II, and 9 cases of type III. MRI images showed all patients had rupture of the rotator cuff. The examination of shoulder arthroscope showed complete rupture of the supraspinatus muscle in 27 cases and acromion impingement in 23 cases. The patients without impingement underwent tear debridement, and the patients with impingement underwent acromioplasty and resection of subacromial bursa after tear debridement. The 3-4 cm incision was made with arthroscopically assisted positioning, and the metal suture anchor was placed on the greater tubercle of humerus to repair rotator cuff. RESULTS: All incisions healed primarily. All patients were followed up 13-27 months (mean, 19 months). No infection, loosening of internal fixation, and rotator cuff re-tear occurred. Pain was relieved and the results was satisfactory after operation. The shoulder range of motion (ROM) at last follow-up was significantly improved when compared with preoperative ROM (P < 0.05). The visual analogue scale (VAS) score was significantly improved from 8.0 +/- 1.8 at preoperation to 1.6 +/- 0.7 at 2 weeks after operation and 0.8 +/- 0.7 at last follow-up (P < 0.05); the University of California Los Angeles (UCLA) score of shoulder was significantly increased from 18.8 +/- 6.6 at preoperation to 32.2 +/- 3.3 at 3 months after operation and 33.6 +/- 2.1 at last follow-up (P < 0.05). CONCLUSION: The effectiveness of arthroscopically assisted treatment of rotator cuff injury is satisfactory. However, long-term effectiveness needs further follow-up observation.