Apelin Alleviates Meniscus Endothelial Cell Apoptosis in Osteoarthritis.

Osteoarthritis (OA) is a degenerative disease characterized by articular cartilage and/or chondrocyte destruction, and although it has long been considered as a primary disease, the importance of meniscus endothelial cell modulation in the subchondral microenvironment has recently drawn attention. Previous studies have shown that apelin could potentially inhibit cellular apoptosis; however, it remains unclear whether apelin could play a protective role in protecting the endothelium in the OA meniscus. In this study, with the advantages of single-cell RNA sequencing (scRNA-seq) data, in combination with flow cytometry, we identified two endothelial subclusters in the meniscus, featured by high expression of Homeobox A13 (HOXA13) and Ras Protein-Specific Guanine Nucleotide Releasing Factor 2 (RASGRF2), respectively. Compared with control patients, both subclusters decreased in absolute cell numbers and exhibited downregulated APJ endogenous ligand (APLN, coding for apelin) and upregulated apelin receptor (APLNR, coding apelin receptor). Furthermore, we confirmed that in OA, decreased endothelial cell numbers, including both subclusters, were related to intrinsic apoptosis factors: one more relevant to caspase 3 (CASP3) and the other to BH3-Interacting Domain Death agonist (BID). In vitro culturing of meniscal endothelial cells purified from patients proved that apelin could significantly inhibit apoptosis by downregulating these two factors in endothelial cell subclusters, suggesting that apelin could potentially serve as a therapeutic target for patients with OA.

[EFFECTIVENESS OF MODIFIED OPERATION FOR TREATMENT OF OLD MONTEGGIA FRACTURE].

OBJECTIVE: To investigate the effectiveness of a modified surgical treatment of old Monteggia fracture. METHODS: Between March 2006 and December 2013, 40 cases of old Monteggia fracture were treated with modified operation. Modified operation procedure included expanding excision of pedicled forearm fascia flap for reconstruction of the annular ligament and repair of elbow radial lateral collateral ligament complex and extending osteotomy of the ulna, callus replantation, and internal fixation with steel plate. There were 26 boys and 14 girls, aged 2-10 years with an average age of 4 years. Injury was caused by falling in 24 cases, by traffic accident in 8 cases, and by falling from height in 8 cases. The disease duration was 2-11 months (mean, 4 months). Four patients had combined radial nerve palsy. RESULTS: Incision healed by first intention after operation, without early complication of radial nerve palsy, fascial compartment syndrome, or decreased hand extensor muscle strength. All the children were followed up 1-5 years (mean, 2.5 years). X-ray films showed fracture healing, and the healing time was 10-20 weeks (mean, 15 weeks). During follow-up, 3 cases had re-dislocation. Neither hand dysfunction caused by hand muscle adhesion nor radial head bottleneck shape change was found. On the basis of the functional evaluation criteria by Mackay, the results were excellent in 32 cases, good in 5 cases, and poor in 3 cases; the excellent and good rate was 92.5% at last follow-up. CONCLUSION: The modified surgical treatment of old Monteggia fracture is an effective method, with good matching of humeroradial joint and without internal fixation of the humeroradial joint.