Core decompression combined with implantation of ß-tricalcium phosphate modified by a BMSC affinity cyclic peptide for the treatment of early osteonecrosis of the femoral head.

Early intervention of osteonecrosis of the femoral head (ONFH) is very important. At present, the therapeutic effect on early ONFH is not completely satisfactory. D7 peptide has special affinity towards bone marrow mesenchymal stem cell (BMSC). Taking advantage of the adsorption/freeze-drying strategy, we constructed D7 cyclic peptide-modified ß-tricalcium phosphate (ß-TCP) scaffolds. The functional ß-TCP scaffolds can enhance adhesion, spreading and proliferation of BMSCs compared with unmodified ß-TCP scaffolds, which was comfired in cytological experiments. In rabbit model of early ONFH, functional ß-TCP scaffolds were stuffed into the cavities after core decompression (CD). Radiographic and histological examination confirmed that CD followed by filling of functional ß-TCP scaffolds can obviously improve the therapeutic effect of early ONFH. Our study provides a new option for curing early ONFH.

BMSC affinity peptide-functionalized ß-tricalcium phosphate scaffolds promoting repair of osteonecrosis of the femoral head.

BACKGROUND: Osteonecrosis of the femoral head (ONFH) is a disabling disease. Early treatment is crucial to the prognosis of the disease. Core decompression (CD) is one of the most commonly used methods for the treatment of early ONFH. But it could not prevent the collapse of the necrotic femoral head. How to improve the therapeutic effect of early ONFH on the basis of CD has become an area of focused research. METHODS: Functional ß-tricalcium phosphate (ß-TCP) scaffolds modified by DPIYALSWSGMA (DPI) peptide, a bone marrow-derived mesenchymal stem cell (BMSC) affinity peptide, were constructed using an adsorption/freeze-drying strategy. The affinity of DPI peptide towards rabbit BMSCs was investigated using flow cytometry and fluorescence cytochemistry. In vitro cell adhesion assay was performed to study the adherent ability of rabbit BMSCs on functional ß-TCP scaffolds. After the rabbit model of early ONFH was established, DPI peptide-modified and pure ß-TCP scaffolds were transplanted into the remaining cavity after CD. Meanwhile, rabbits treated with pure CD were used as blank control. Twelve weeks after surgery, histological analysis was performed to show the therapeutic effect of three methods on early ONFH. RESULTS: The result of ImageXpress Micro Confocal indicated that fabricated DPI peptide-modified functional ß-TCP scaffolds exhibited green fluorescence. In flow cytometry, the average fluorescence intensity for rabbit BMSCs incubated with FITC-DPI was significantly higher than that of FITC-LSP (P = 2.733 × 10-8). In fluorescence cytochemistry, strong fluorescent signals were observed in rabbit BMSCs incubated with FITC-DPI and FITC-RGD, whereas no fluorescent signals in cells incubated with FITC-LSP. In cell adhesion assay, the number of adherent cells to ß-TCP-DPI scaffolds was more than that of pure ß-TCP scaffolds (P = 0.033). The CD + ß-TCP-DPI group expressed the lowest vacant bone lacunae percentage compared to CD group (P = 2.350 × 10-4) and CD + ß-TCP group (P = 0.020). The expression content of COL1 in CD + ß-TCP-DPI group was much higher than CD group (P = 1.262 × 10-7) and CD + ß-TCP group (P = 1.666 × 10-7) according to the integrated optical density (IOD) analyses. CONCLUSION: Functional ß-TCP scaffolds modified by DPI peptide were successfully synthesized using an adsorption/freeze-drying strategy. DPI peptide has good affinity towards rabbit BMSCs. The adhesion of rabbit BMSCs on DPI peptide-modified ß-TCP scaffolds was apparently enhanced. CD followed by implantation of DPI peptide-modified ß-TCP scaffolds can apparently improve the treatment of early ONFH compared with pure CD and CD followed by implantation of unmodified ß-TCP scaffolds. Our current study provides an improved method for the treatment of early ONFH.

A specific affinity cyclic peptide enhances the adhesion, expansion and proliferation of rat bone mesenchymal stem cells on ß­tricalcium phosphate scaffolds.

Osteonecrosis of the femoral head (ONFH) is a common osteological disease. Treatment of ONFH prior to the collapse of the femoral head is critical for increasing therapeutic efficiency. Tissue engineering therapy using bone mesenchymal stem cells (BMSCs) combined with a scaffold is a promising strategy. However, it is currently unclear how to improve the efficiency of BMSC recruitment under such conditions. In the present study, a specific cyclic peptide for Sprague­Dawley rat BMSCs, CTTNPFSLC (known as C7), was used, which was identified via phage display technology. Its high affinity for BMSCs was demonstrated using flow cytometry and fluorescence staining. Subsequently, the cyclic peptide was placed on ß­tricalcium phosphate (ß­TCP) scaffolds using absorption and freeze­drying processes. Adhesion, expansion and proliferation of BMSCs was investigated in vitro on the C7­treated ß­TCP scaffolds and compared with pure ß­TCP scaffolds. The results revealed that C7 had a promoting effect on the adhesion, expansion and proliferation of BMSCs on ß­TCP scaffolds. Therefore, C7 may be effective in future tissue engineering therapy for ONFH.

Exosomes derived from platelet-rich plasma present a novel potential in alleviating knee osteoarthritis by promoting proliferation and inhibiting apoptosis of chondrocyte via Wnt/ß-catenin signaling pathway.

BACKGROUND: Platelet-rich plasma (PRP) provides a nonsurgical approach for treating osteoarthritis (OA). Exosomes that play vital roles in intercellular communication have been studied extensively. Here, we investigated the therapeutic potential and molecular mechanism of exosomes derived from PRP (PRP-Exos) in alleviating OA. METHODS: Exosomes derived from PRP(PRP-Exos) were isolated and purified using the exoEasy Maxi Kit and then identified and analyzed. Primary rabbit chondrocytes were isolated and treated with interleukin 1 beta (IL-1ß) to establish the OA model in vitro. Proliferation, migration, and apoptosis assays were measured and compared between PRP-Exos and activated PRP (PRP-As) to evaluate the therapeutic effects on OA. The mechanism involving the Wnt/ß-catenin signaling pathway was investigated by Western blot analysis. In vivo, we established animal knee OA model by surgery to compare the therapeutic effect of PRP-Exos and PRP-As. RESULTS: We successfully isolated and purified exosomes from PRP using the exoEasy Maxi Kit. We also isolated and identified chondrocytes from the New Zealand white rabbit and established the IL-1ß-induced OA model; meanwhile, PRP-Exos and PRP-As both inhibited the release of tumor necrosis factor-α(TNF-α) and there was no statistically significant difference between the two. In proliferation, migration, scratch assay, the promoting effect of PRP-Exos was significantly more better than PRP-As. Furthermore, PRP-Exos could significantly decreased apoptotic rate of OA chondrocyte compared with PRP-As. In Western blot analysis, the expression of ß-catenin, and RUNX2, Wnt5a were increased in IL-1ß-treated chondrocytes, but PRP-Exos and PRP-As could both reverse these changes, and the reversal effect of the former was better than the latter. In vivo, we found that both PRP-Exos and PRP-As displayed the progression of OA, and the effect of PRP-Exos was obviously better than PRP-As by chondrocyte count and Osteoarthritis Research Society International (OARSI) scoring system. CONCLUSION: The therapeutic effects of PRP-Exos on OA were similar or better compared with those of PRP-As in vitro or in vivo. PRP-Exos acting as carriers containing growth factors derived from PRP present a novel therapy for OA by activating the Wnt/ß-catenin signaling pathway.

Biopanning of mouse bone marrow mesenchymal stem cell affinity for cyclic peptides.

Osteonecrosis of the femoral head (ONFH) is a refractory disease present worldwide. In the development of therapies for this disease, mesenchymal stem cells (MSC) are a promising candidate cell source in tissue engineering (TE) and regenerative medicine. MSCs harvested from bone marrow (BM) are the gold standard. A significant barrier for BMMSC­based therapies is the inability and decreased number of BMMSCs in the tissues of interest. The ability to recruit BMMSCs efficiently to defective or injured sites in tissues or organs, for example the necrotic area of the femoral head in vivo, has been a major concern. In the present study, a peptide sequence (CDNVAQSVC), termed D7, was identified through phage display technology using C57BL/6 mouse BMMSCs. Subsequent analysis suggested that the identified loop­constrained heptapeptide exhibited a high specific affinity for mouse BMMSCs. Due to this specific affinity for BMMSCs, the present study provides a selective method to improve MSC­based TE strategies for the treatment of ONFH.

Enhanced adhesion and proliferation of bone marrow mesenchymal stem cells on ß­tricalcium phosphate modified by an affinity peptide.

Mesenchymal stem cells (MSCs) are often used in orthopedic tissue engineering, and bone marrow­derived mesenchymal stem cells (BMSCs) are currently considered the gold standard. One of the most important issues in MSC­based tissue engineering therapy is the low number of MSCs in pathological tissues. Achieving efficient recruitment of MSCs to defective or damaged tissues in vivo has been a difficult hurdle. The aim of the present study was to construct a biomaterial that can effectively recruit BMSCs to facilitate the repair of pathological tissues. So functional ß­tricalcium phosphate (ß­TCP) was synthesized using the BMSC affinity peptide DPIYALSWSGMA (DPI) adsorbed onto ß­TCP through an adsorption/freeze­drying strategy. C57BL/6 mouse­derived BMSCs were seeded onto the DPI peptide­modified ß­TCP (ß­TCP­DPI); in vitro experiments demonstrated that ß­TCP­DPI enhanced BMSC adhesion and proliferation compared with unmodified ß­TCP. Results from the present study indicated that functional ß­TCP may be used as an ideal scaffold in tissue engineering and in regenerative medicine.

[Minimally invasive surgery to treat severe acromioclavicular dislocation combined with coracoid process fracture].

OBJECTIVE: To discuss the diagnosis and minimally invasive surgical treatment on severe acromioclavicular dislocation combined with coracoid process fracture. METHODS: Using 2 incisions of shoulder to expose and fix coracoid process and acromioclaricular joint and to repair damaged acromioclavicular ligament in 7 cases from March 1998 to March 2009. There was 2 males and 5 females in the patients. The age was from 23 to 57 years with an average of 44 yeas. The time from injury to operation was 3-7 d with an average of 4 days. According to Eyres typing, 2 cases were type 11 B, 5 cases were type III B. RESULTS: Seven patients were followed up from 6 months to 2 years with an average of 1 year. According to Karlsson criteria, 7 cases got grade A. CONCLUSION: Using 2 incisions of shoulder to expose and fix acromioclaricular joint and coracoid process with strong pertinence, reliable fixation and small tissue injury, which is a minimally invasive and effective method for severe acromioclavicular dislocation combined with coracoid process fracture.