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.
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 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）
Objective To evaluate the host immune reaction against adenovirus mediated human bone morphogenetic protein 2 (Adv-hBMP-2) gene therapy in repairof tibial defects. Methods Twelve goats were made 2.1 cm segmental defects in he tibial diaphysis and divided into 2 groups. AdvhBMP2 transfected marrow mesenchymal stem cells(MSCs) and untransfected MSCs were implanted into the defect sites of transfected group(n=7) and untransfected group (n=5), respectively. The defect repair was observed by X-ray films after 4, 8, 16 and 24 weeks of transplantation and cellular and humoral immune reactions to adenovirus were assayed before implantation and after implantation. Results More bony callus was found in the bone defects of transfected group. The healing rates were 6/7 in transfected group and 2/5 in untransfected group, respectively at 24 weeks after implantation. The mixed culture of lymphocytes and MSCs showed that the lymphocytes stimulation indexes (SI) increased 14 days after implantation, and there was significant difference between the transfected group (4.213±1.278) and the untransfected group(－0.310±0.147，Plt;0.05); SI decreased after 28 days, but there was no significant difference between the transfected group (2.544±0.957) and the untransfected group (3.104±0.644，Pgt;0.05). After 14, 28, 49, and 120 days of treatment, the titer values of neutralizing antibody against Adv-hBMP-2 (log0.1) were 2.359±0226, 2.297±0.200, 2.214±0.215 and 2.297±0.210 in transfected group, and -0.175±0.335, -0.419±0.171, 0±0.171 and 0.874±0.524 in untransfected group, being significant differences betweentwo groups(Plt;0.05). Conclusion Adenovirus mediated BMP-2gene therapy can cause cellular and humoral immune reactions against adenovirus, which can eliminate the influence of adenoviral genes and proteins within a certain period.
Objective To review the research progress of the treatment of osteosarcoma, and to thoroughly understand its current state of research and prospect so as to lay a sol id foundation for the cl inical treatment. Methods The cl inical and experimental research l iteratures about treatment of osteosarcoma were extensively reviewed and analyzed. Results The present treatment of osteosarcoma is still need to comprehensive therapy which combine chemotherapy and surgical treatment. There are some progresses in gene therapy and molecular targeting therapy which can improve survival rate. Furthermore, well-designed studies and cl inical trials are needed to evaluate the potential therapeutic impact before they are used in cl inical. Conclusion Advancement in chemotherapeutic regimens has improved survival and l imb-sparing surgery in the treatment of osteosarcoma, but the progress of gene therapy and molecular targeting therapy gives new hope for osteosarcoma patients.
Objective To explore the feasibility of recombinant adeno-associated virus (rAAV) as a vector for the gene therapy of liver cancer. Methods The rAAV/enhance green fluorescein protein (EGFP) recombinant was prepared by the routine method of two plasmids cotransfection.Results The experiment showed that one 10cm plate could produce 107-108 infection unit recombinant by the method of two plasmids cotransfection, and the transduction of HepG2 cell was increased with the increase of infection dosage of rAAV. About 100 multiplicity of infection (MOI) AAV vector could make all the tumor cell light. Conclusion Liver cancer cell can be efficiently transduced by rAAV, and AAV vector may be a valuable vector for the gene therapy of liver cancer.
ObjectiveTo explore the new gene therapy method for tumor, the recombinant Caspase3 gene (rcaspase3) eukaryotic expression plasmid was constructed by molecular biologic method. MethodsThe eukaryotic expression plasmid pcDNA3.1(+)/rCaspase3 was constructed by rearrangement of the large subunit and small subunit of Caspase3 and it was transfected into pancreatic carcinoma cells(PCⅡ). After being transfected, the expression of rCaspase3 mRNA in pancreatic carcinoma cells was detected by RTPCR and it’s apoptotic activity was detected by FCM. ResultsThe sequence of rCaspase3 showed that the recombinant molecules (rCaspase3) now had its’ small subunit preceding its’ large subunit. After pancreatic carcinoma cells being transfected with the pcDNA3.1(+)/rCaspase3 by liposomes, a 894 bp strap was observed by RTPCR. No strap was found in control groups. A transparent hypodiploid karyotype peak was found by FCM.ConclusionThe plasmid of pcDNA3.1(+)/rCaspase3 has been constructed successfully. rCaspase3 has apoptotic activity and can be used as target gene in gene therapy for pancreatic carcinoma.
Objective To investigate the effect of the vascular endothelial growth factor (VEGF) gene therapy, the surgical delay, and the combination of the two therapeutic approaches on the survival of the rat over-area abdominal axial skin flap. Methods In 48 male Wistar rats (weight, 400-450 g), a model of the abdominal axial skin flap supplied by the superficial epigastric blood vessel was created. The rats were randomly divided into 6 groups: Group A (the blank group), Group B (the gene-therapy-during-operation group), Group C (the gene-therapy-before-operation group), Group D (themerely-surgical-delay group), Group E (the gene-therapy-during-surgical-delay group), and Group F (the gene-therapy-aftersurgical-delay group). Seven days after operation, the survival rate of the skin flap was measured; the specimens were harvested from the skin flap for a histological investigation of themicrovessels and for an immunohistochemical staining to observe the expression of VEGF165. Results The average survival rate of the skinflap was significantly greater in each of the treated groups than in Group A (Plt;0.05); the rate was the greater in Group E (Plt;0.05), but with no statistically significant difference between the other treated groups (Pgt;0.05). The average number of the microvessels was significantly greater in Groups B, C, E andF than in Groups A and D (Plt;0.05), but with no statistically significant difference between Groups B, C, E and F and between Groups A and D (Pgt;0.05). The lumen diameter of the microvessels was significantly greater in Group D than in Groups E and F (Plt;0.05), and the diameter was significantly greater in Groups D, E andF than in the other groups (Plt;0.05). More deposition of VEGF DNA detected by the immunohistochemical staining was in Groups B, C, E and F than in Groups A and D. There was no newly-formed blood vessel in the rat cornea in the treated groups.Conclusion Both the administration of pcDNA4-VEGF165 and the surgical delay can improve the survival of the rat abdominal axial skin flap, but the mechanism of the effect is different in explanation. The combination of the two therapeutic approaches can achieve a better effect.
Gene therapy develops very rapidly during the resent years. Great prospects have been demonstrated from basic study and clinic test. However, the gene therapy in CNS is still in stage of laboratory. The research status and prospects of gene therapy in spinal cord injury (SCI) were introduced. The basic principle is to transplant certain cells genetically modified with NTFs to the site of the injuried spinal cord, then NTFs are expressed in vivo and stimulate axon regrowing. Virus vectors are usually used for gene transfer because of their high rate of transfection, and the receptor cells include fibroblast, myoblast, etc. Nowadays, gene therapy in SCI is studied in many laboratories and the problems include: 1. The ideal components of transfer gene. 2. The choice of carrier. 3. Immune reaction, and prolonged survival and persistent expression of the receptor cells in the spinal cord. If these problems could be solved, the gene therapy would become the key method in the therapy of SCI.