Myosin heavy chain 2 (MYH2) expression in hypertrophic chondrocytes of soft callus provokes endochondral bone formation in fracture.

AIMS: Muscle-bone interactions during fracture healing are rarely known. Here we investigated the presence and significance of myosin heavy chain 2 (MYH2), a component of myosin derived from muscles, in fracture healing. MAIN METHODS: We collected five hematoma and seven soft callus tissues from patients with distal radius fractures patients, randomly selected three of them, and performed a liquid chromatography-mass spectrometry (LC-MS) proteomics analysis. Proteomic results were validated by histological observation, immunohistochemistry, and immunofluorescence for MYH2 expression. These findings were further confirmed in a murine femoral fracture model in vivo and investigated using various methods in vitro. KEY FINDINGS: The LC-MS proteomics analysis showed that MYH proteins were enriched in human soft calluses compared to hematoma. Notably, MYH2 protein is upregulated as high rank in each soft callus. The histological examination showed that MYH2 expression was elevated in hypertrophic chondrocytes within the human soft callus. Consistent with human data, Myh2 were significantly co-localized with Sox9 in hypertrophic chondrocytes of murine femoral fracture, in comparison to pre-hypertrophic and proliferating chondrocytes. Soluble MYH2 protein treatment increased MMP13 and RUNX2 expression in chondrocytes. In soluble MYH2 treatment, proliferation of chondrocytes was not altered, but the osteogenic and chondrogenic features of chondrocytes increased and decreased during differentiation, respectively. SIGNIFICANCE: These findings indicate the potential of soluble MYH2 protein as a promising therapeutic strategy for promoting endochondral bone formation in chondrocytes following fracture.

Surgical Outcomes of Percutaneous Pinning and Open Locking Plating in Patients With Intra-articular Fractures of the Base of the Fifth Metacarpal.

PURPOSE: The purpose of the study was to demonstrate the results of surgical treatment, including percutaneous K-wire fixation after closed reduction (CRKF) or locking plate fixation after open reduction (ORPF), in patients with intra-articular fractures of the base of the fifth metacarpal. METHODS: We retrospectively reviewed data of 29 patients who received surgical treatment for closed, intra-articular fractures of the base of the fifth metacarpal and were followed up for at least 1 year after surgery. Sixteen of the 29 patients underwent CRKF, whereas 13 patients underwent ORPF. Attempts were made to address intra-articular step-off with closed reduction in all the patients; however, if inadequate, ORPF was performed. Clinical outcomes were evaluated using Disabilities of the Arm, Shoulder, and Hand scores, visual analog scale pain scores, the total active motion (TAM) of the little finger, and grip strength. Osseous union and posttraumatic arthritis of the fifth carpometacarpal joint were also evaluated. RESULTS: K-wire fixation after closed reduction was performed for 13 simple fractures and 3 comminuted fractures; ORPF was performed for 6 simple fractures and 7 comminuted fractures. All the patients had satisfactory subjective outcomes with over 90% grip strength compared with that on the contralateral side and nearly full TAM. All the patients in both the groups achieved osseous union. There were five cases of grade 1 posttraumatic arthritis after CRKF and seven cases of grade 1 posttraumatic arthritis after ORPF. CONCLUSIONS: Surgical treatment provided satisfactory results in patients with intra-articular fractures of the base of the fifth metacarpal treated with either CRKF or ORPF. Our data showed that the patients who underwent CPKF had good results, and those who underwent ORPF after attempt failure of close reduction also had good results. Our experience suggests that ORPF can be a backup plan when CRKF cannot be accomplished in a satisfactory way. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

[The immune responses of the fusion protein consisted of two copies of T-cell and B-cell epitopes of food-and-mouth disease virus VP1 type O and LTB and STI enterotoxins of Escherichia coli].

A nucleotides fragment 2020VP1 related to T-cell epitope (aa21-40) and B-cell epitope (aa141-160) of VP1 of Food-and-mouth disease virus (FMDV)type O was synthesized, and the recombined expression vector r2020-LTB-2020-STI was correctly constructed, which was used to express the fusion protein consisted of two copies of aa21-40aa141-160 of FMDV VP1 and LTB and STI Enterotoxins of Escherichia coli. The fusion protein with molecular weight of about 45kD was successfully expressed in E.coli BL21(DE3) RIL at high level and confirmed by SDS-PAGE. The purified fusion protein could be specifically recognized by CTB antibody. The purified protein was then used to vaccinate guinea pigs, rabbits and Balb/c mice at 6-8 week age, and immune responses were finally observed. The fusion protein could induce proliferation of spleen T cells in vaccinated guinea pigs and elicit a high level of neutralizing antibody in rabbits. It could be concluded that the fusion protein could activate FMDV-specific cellular immune-response and humoral immune-response simultaneously. At the same time, the vaccinated mice could survive challenge of Enterotoxigenic Escherichia coli C83902, and the sera of vaccinated rabbits could neutralize the STI toxin. Moreover, the fusion protein had no STI toxicity, indicating that the fusion protein had LTB and STI immunogenicities. Therefore, it can be concluded that the fusion protein could be explored as a potentially efficient FMDV and ETEC vaccine.