Objective To summarize the recent progress of cell-based approaches for promoting bone regeneration in distraction osteogenesis (DO). Methods Recent literature concerning enhancement of bone regeneration following DO using cell-based approaches was reviewed and analyzed. Results An overview of 4 different cell-based approaches was mainly provided: single cell injection, cell scaffold-based strategies/injectable tissue engineered bone, microtissue technology or cell aggregate technology, and stem cell gene therapy. Each has its advantages and disadvantages. Other methods are still in the experimental research except that compound injection of bone marrow mesechymal stem cells and platelet-rich plasma has been applied to clinical practice. Conclusion The cell-based approach is a promising strategy in the field of bone regenerative medicine. These approaches have bright future in promoting bone regeneration and reducing the treatment period in DO in the clinical application. However, well-designed preclinical studies are required to establish safe and effective guidelines for cell-based approaches to promoting bone regeneration during DO.
Objective To give a prel iminary experimental evidence and to prove chitosan and allogeneic morsel ized bone as potential bone substitutions in repairing rabbit radius segmental defect. Methods Chitosan and allogeneic morsel ized bone were mixed with various ratios (1 ∶ 5, 1 ∶ 10, 1 ∶ 25, 1 ∶ 50, and 1 ∶ 100). After preparation, the physicaland chemical properties of the composites were prel iminary detected; the composites at the ratios of 1 ∶ 50 and 1 ∶ 25 had good physical and chemical properties and were used for the animal experiment. The radius segmental defects of 15 mm in length were made in 50 adult New Zealand white rabbits (weighing 2.5-3.0 kg), then the animals were divided into 2 groups. In groups A and B, chitosan/allogeneic morsel ized bone composites were implanted at the ratio of 1 ∶ 50 and 1 ∶ 25, respectively. After 1, 2, 4, 8, and 12 weeks of operation, the gross, histological, immunohistochemical observations were performed. Before the rabbits were sacrified, X-ray films were taken; the serum calcium and alkal ine phosphatase (ALP) concentration were measured; and the biomechanical measurement was carried out at 12 weeks. Results The results of gross observation were essentially consistent with those of the X-ray films. The histological observation showed that the bone formation was earl ier in group A than in group B; the amount of new bone formation in group A was more than that in group B; and the bone forming area in group A was bigger than that in group B (P lt; 0.05) at 4 and 8 weeks after operation. The immunohistochemical staining showed that vascular endothel ial growth factor and insul in-l ike growth factor receptor II proteins expressed in the cytoplasm of 2 groups after 4 and 8 weeks, and the expression in group A was higher than that in group B (P lt; 0.05). There was no significant difference in the serum calcium concentration between 2 groups at each time point (P gt; 0.05). After 4 and 8 weeks, the ALP concentration in group A was significantly higher than that in group B (P lt; 0.05). After 12 weeks, the radius maximum bending loads of groups A and B were (299.75 ± 27.69) N and (278.54 ± 17.09) N, respectively, showing significant difference (t=4.045,P=0.002). Conclusion The composite of chitosan and allogeneic morsel ized bone has good osteogeneic activity and can beused as a bone tissue engineering scaffold, and the optimum ratio of chitosan to allogeneic morsel ized bone was 1 ∶ 50.
Objective To investigate the mode and influential factor of newbone formation following distraction osteogenesis in mandibular lengthening. Methods Corticotomy was performed on bilateral mandibles in twelve adult male goats. A custommade distractor was used to lengthen the mandible at a rate of 1mm/day for 10 days (total 10 mm elongation). Four goats were sampled respectivelyat 2, 4 and 8 weeks after completion of distraction. The lengthening mandibles were examined by roentgenography and histology. Results Newly formed callus was observed in the distraction gap after mandibular lengthening. The new bone exhibited intramembranous ossification generally, but cartilage islands could be found in the specimen that diastractor loosed. Conclusion The above findings indicate that the mode of new bone formation in mandibular lengthening following distraction osteogenesis appears to be intramembranous ossification and that endochondral ossification takes place in case distractor has loosened.
ObjectiveTo review the research progress of the co-culture system for constructing vascularized tissue engineered bone. MethodsThe recent literature concerning the co-culture system for constructing vascularized tissue engineered bone was reviewed, including the selection of osteogenic and endothelial lineages, the design and surface modification of scaffolds, the models and dimensions of the co-culture system, the mechanism, the culture conditions, and their application progress. ResultsThe construction of vascularized tissue engineered bone is the prerequisite for their survival and further clinical application in vivo. Mesenchymal stem cells (owning the excellent osteogenic potential) and endothelial progenitor cells (capable of directional differentiation into endothelial cell) are considered as attractive cell types for the co-culture system to construct vascularized tissue engineered bone. The culture conditions need to be further optimized. Furthermore, how to achieve the clinical goals of minimal invasion and autologous transplantation also need to be further studied. ConclusionThe strategy of the co-culture system for constructing vascularized tissue engineered bone would have a very broad prospects for clinical application in future.
ObjectivesTo systematically review the efficacy of resorbable membrane and non-resorbable membrane in dental implant to guide bone regeneration.MethodsPubMed, EMbase, The Cochrane Library, Web of Science, VIP, CNKI and WanFang Data databases were electronically searched to collect randomized controlled trials (RCTs) of the efficacy of resorbable membrane and non-resorbable membrane in dental implant to guide bone regeneration from inception to February 20th, 2019. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 22 RCTs involving 1 995 patients were included. The results of meta-analysis showed that: the resorbable membrane group was superior to non-resorbable membrane group in terms of repair success (RR=1.21, 95%CI 1.17 to 1.26, P<0.000 01), the bone thickness (MD=0.40, 95%CI 0.36 to 0.43, P<0.000 01), bone graft thickness(MD=0.40, 95%CI 0.35 to 0.46, P<0.000 01), patient satisfaction (RR=1.19, 95%CI 1.04 to 1.36, P=0.009), histological evaluation in bone contact (MD=4.82, 95%CI 0.14 to 9.50, P=0.04) and the total mineralized tissue (MD=3.73, 95%CI 0.32 to 7.14, P=0.03). They also had lower adverse reaction rate(RR=0.28, 95%CI 0.20 to 0.39, P<0.000 01) and changes of bone defect width from preoperative to 6 months postoperatively (MD=−0.62, 95%CI −0.93 to −0.31, P<0.000 01) with statistically significant differences. However, there was no significant difference in histological evaluation of non-mineralized tissue(MD=−2.48, 95%CI −5.81 to 0.85, P=0.14) between two groups.ConclusionsCurrent evidence shows that the resorbable membrane has better repairing effects, for which helps to promote the development of bone and bone graft, reduce the incidence of adverse reactions, which has good safety and effectiveness. Due to limited quality and quantity of the included studies, more high-quality studies are required to verify above conclusion.