OBJECTIVE: From the point of view of material science, the methods of tissue repair and defect reconstruct were discussed, including mesenchymal stem cells (MSCs), growth factors, gene therapy and tissue engineered tissue. METHODS: The advances in tissue engineering technologies were introduced based on the recent literature. RESULTS: Tissue engineering should solve the design and preparation of molecular scaffold, tissue vascularization and dynamic culture of cell on the scaffolds in vitro. CONCLUSION: Biomaterials play an important role in the tissue engineering. They can be used as the matrices of MSCs, the delivery carrier of growth factor, the culture scaffold of cell in bioreactors and delivery carrier of gene encoding growth factors.
Objective To study the vascularization of the compositeof bone morphogenetic protein 2 (BMP-2) gene transfected marrow mesenchymal stem cells (MSCs) and biodegradable scaffolds in repairing bone defect. Methods Adenovirus vector carrying BMP-2 (Ad-BMP-2) gene transfected MSCs and gene modified tissue engineered bone was constructed. The 1.5 cm radial defect models were made on 60 rabbits, which were evenly divided into 4 groups randomly(n=15, 30 sides). Different materials were used in 4 groups: Ad-BMP-2 transfected MSCs plus PLA/PCL (group A), AdLacz transfected MSCs plus PLA/PCL (group B), MSCs plus PLA/PCL (group C) and only PLA/PCL scaffolds (group D). The X-ray, capillary vessel ink infusion, histology, TEM, VEGF expression and microvacular density counting(MVD) were made 4, 8, and 12 weeks after operation. Results In group A after 4 weeks, foliated formed bones image was observed in the transplanted bones, new vessels grew into the bones, the pores of scaffolds were filled with cartilage callus, osteoblasts with active function grew around the microvessels, and VEGF expression and the number of microvessels were significantly superior to those of other groups, showing statistically significant difference (Plt;0.01); after 8 weeks, increasingly more new bones grew in the transplanted bones, microvessels distended and connected with each other, cartilage callus changed into trabecular bones; after 12 weeks, lamellar bone became successive, marrow cavity recanalized, microvessels showed orderly longitudinal arrangement. In groups B and C, the capability of bone formation was weak, the regeneration of blood vessels was slow, after 12 weeks, defects were mostly repaired, microvessels grew among the new trabecular bones. In group D, few new vessels were observed at each time, after 12 weeks, broken ends became hardened, the defectedarea was filled with fibrous tissue. Conclusion BMP-2 gene therapy, by -upregulating VEGF expression, indirectly induces vascularization ofgrafts,promotes the living of seed cells, and thus accelerates new bone formation.
Objective To review the current concepts of gene therapy approachesmediated by adenovirus vectors for bone trauma and bone disease. Methods The recent literature concerned gene therapy mediated by adenovirus vectors was reviewed, which provides new insights into the treatments of bone trauma and bone disease. Results Adenovirus vectors was efficient, achieved high expression after transduction, and could transfer genes to both replicating and nonreplicating cells, such as osteoblasts, osteoclasts, fibroblasts, chondrocytes, bone marrow stromal cells, etc. Gene therapy mediated by adenovirus vectors achieved affirmative results in enhancing bone union and in curing bone diseases, such as osteoporosis and rheumatoid arthritis. Conclusion Gene therapy mediatedby adenovirus offers an exciting avenue for treatment of bone trauma and bone diseases.
Objective To explore a new method of treating early avascular necrosis of femoral head (AVNFH). Methods Sixty-nine New Zealand adult rabbitswith a mean weight of 2.8 kg after AVNFH presenting were randomly divided into three groups. In group A, deproteinized bone(DPB) combined with the recombinant plasmid pcDNA3.1/vascular endothelial growth factor 165(VEGF165) was implanted in the drilled channel of the necrotic femoral head. In group B, only DPB was implanted. In group C, channel was drilled without DPB or plasmid implanted. Femoral head specimens were obtained 3 days, 1, 2, 4, 8 and 16 weeks after operation. The expression of VEGF165 was examined by RT-PCR, Western blot and immunohistochemical techniques. X-ray testedbone formation generally. Angiogenesis and repair of the femoral head were observed by histological and histomorphometric analysis. Results In group A, the expressions of VEGF165 mRNA and protein were detected 3 days postoperatively, reached apex 1 week and lasted more than 3 weeks after implantation. The ratios of IOD of collagen type Ⅰ were 0.29±0.11, 0.55±0.13 and 0.67±0.10 IOD/μm2 respectively at 2, 4 and 8 weeks postoperatively and the ratios of IOD of new capillary vessels were 0.33±0.10and 0.57±0.16 IOD/μm2 respectively at 2, 4 weeks postoperatively in group A, showing statistically significant difference (Plt;0.01) when compared with groups B and D. X-ray test indicated much bone callus formed early. Conclusion Transfection of the VEGF165 gene can enhance local angiogenesis at early stage andDPBVEGF165 compound can improve bone formation. Deproteinized bone combined with VEGF165 gene provides a potential method for therapy of osteonecrosis.
Objective To invesitgate the influence of recombinant adenovirus vector of human pigment epithelium-derived factor（AV-hPEDF）on retinal new vessels mediated by recombinant adenovirus vector. Methods Twenty 7-days-old Sprague-Dawley (SD) rat were divided into two groups randomly after the establishment of retinal neovascularization model. At postnatal 14 day, they were accepted intravitreal injection with blankadenovirus-vector (AV-Blank group) and adenovirus-vector PEDF(AV-PEDF group) respectively. The retinal vascular endothelial cells were counted, the PEDF mRNA and protein expression in retina and vitreous were determined by reverse transcriptionpolymerase chain reaction (RT-PCR) and immunohistochemistry. Results After injection with medicine, the number of RNV was decreased obviously in AV-PEDF group（t＝42.009，Plt;0.001）;the protein expression of retinal PEDF was increased obviously in AV-PEDF group（t=36.638，Plt;0.001）; the PEDF mRNA expression in vitreous was also increased obviously in AV-PEDF group （t=9.128，Plt;0.001）. Conclusion Recombinant Adenovirus vector mediated PEDF can raise the PEDF expression in the retinal and vitreous neovascularized tissues in rat, which suggested that the expression of PEDF may be related to inhibition and reduction of RNV.
Duchenne muscular dystrophy is an X-linked inherited progressive degenerative muscle disease caused by mutations in the dystrophin gene, and is one of the most common progressive muscular dystrophies. We will review the selection of genetic diagnosis methods for Duchenne muscular dystrophy, the selection of experimental animal models, and treatment for the primary cause (including gene replacement therapy, exon skipping therapy, genome editing, stop codon read-through therapy, and stem cell therapy), the treatment of secondary pathological reactions and methods of assessing disease progression. The purpose is to enrich clinicians’ knowledge of the disease and provide a reference and help for the clinical diagnosis and treatment of Duchenne muscular dystrophy.
Objective To study the effect of direct bone morphogenetic protein 2 (BMP-2) gene therapy mediated by adenovirus on repairing bone defect. Methods The radial defect models were made on 60 rabbits, which were evenly divided into 4 groups randomly. The 4 groups were treated with different materials: group A, adenovirus carrying BMP-2 gene (AdBMP-2) plus bovine cancellous bone (BCB); group B, reconstructed BMP-2 plus BCB; group C, AdLacz plus BCB; and group D, only BCB scaffolds. The X-ray, histological examination, biomechanics analysis, and immunohistochemical staining were made 4, 8, and 12 weeks after the operation. Results Group A gained better effect in the volume of new bones, the anti-bending intensity of the healing bone, and the expression of BMP-2 than those of group B. The defect in group A was healed. No new bones were observed in group C and group D. Conclusion Direct BMP-2 gene therapy is easy to perform and has veryb osteoinduction ability. It is a good method to repair segmental bone defects.
Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes, which seriously threatens the vision of patients. The pathogenesis of DR Is complex and involves many pathophysiological processes. At present, the treatment methods for DR Mainly include panretinal laser photocoagulation, vitrectomy and vitreous cavity injection, etc. However, each treatment method has certain limitations. In recent years, remarkable progress has been made in the field of drug treatment of DR, especially in anti-vascular endothelial growth factor drugs, anti-inflammatory drugs, anti-oxidative stress damage drugs, neuroprotective agents, gene therapy and stem cell therapy. These drugs not only improve the effectiveness of treatment, but also expand the range of treatment options. In addition, by carrying DR Treatment drugs on carriers such as nanoparticles, hydrogels and photosensitive materials, continuous and efficient release of drugs in the eye is achieved, thereby extending the time interval of administration and reducing the need for frequent treatment of patients. In the future, based on biomarker detection technology, it is expected to promote the development of personalized and precise treatment, which can develop more accurate treatment plans for patients and improve the efficacy.
ObjectiveTo predict as well as bioinformatically analyze the target genes of has-miR-451. MethodsmiRBase, miRanda, TargetScan and PicTar were used to predict the target genes of hsa-miRNA-451. The functions of the target genes were demonstrated by Gene Ontology and pathway enrichment analysis. P < 0.05 was set as statistically significant. Results18 target spots of hsa-miRNA-451 were predicted by 3 databases or prediction software at least. The functions of the target genes were enriched in proliferation and development of epithelial cells and regulation of kinase activity (P < 0.05). Pathway analysis showed that transforming growth factor-beta signaling pathway, mitogen-activated protein kinase signaling pathway, epidermal growth factor signaling pathway, Wnt signaling pathway and mammalian target of rapamycin signaling pathway were significantly enriched (P < 0.05). Conclusionhsa-miRNA-451 might be involved in various signaling pathways related to proliferation and development of epithelial cells.
Objective To observe the expression of the pigment epithelium derived growth factor (PEDF) in retina and the effects of PEDF for vascular endothelial growth factor (VEGF) and retinal microvascular after recombinant adeno-associated virus mediated pigment epithelium derived factor（rAAV-mediated-PEDF）transferred retina of diabetic rats. Methods Male Wister rats were induced diabetes with intraperitoneal injection of streptozocin, then divided into 1 month group (DM1), 3month group(DM3) and 6 month group randomly. In diabetic rats, right eyes were injected rAAV2CMVhPEDF into vitreum as treat group,left eyes were injected into rAAV2-CMV-GFP (1times;1011 v.g/ml) as self-control group. In normal rats, right eyes were punctured but not injected (CONf), left eyes let it be without any disposal. The levels of VEGFmRNA and hPEDFmRNA in retina were evaluated using RT-PCR in different period. The protein levels of VEGF, PEDF within the retina were determined using western blot. The change of retinal capillary were observed through retinal vascular flattening. Result The expression of hPEDFmRNA in retina was enhanced persistence after rAAV2-CMV-hPEDF injected, achieved climax until 6 months. The levels of PEDF were also incerased consecutive, the differences were statistically significant in treatment group compared with own control group （Plt;0.01）. Levels of mRNA and protein of VEGF at different time-points among therapy group were not statistically significant, all obviously higher than normal （Plt;0.05），but all lower obviously than respectively own control group at the same timepoint （Plt;0.01）. The morphology of retinal capillary was not different significant with normal rats in 1 month diabetic rats. Morphology changes of therapy groups were less than those of respective own control group in DM3 and DM6. Conclusion Intravitreous injection rAAV2-CMV-hPEDF can increase expression of mRNA and protein of PEDF，alleviate lesion of retinal microvascular in early period of diabetic rats and supress expression of VEGF in retina of diabetic rats.The regulation occur on mRNA level. （Chin J Ocul Fundus Dis，2008，24：259-264）