Objective To introduce the latest advances of research on repair of the degenerative intervertebral disc with gene transduction.Methods The recentlypublished articles about the treatment of degenerative disc with gene transduction were reviewed, especially the articles published during the recent 5 years about the application of this therapy to regulating the synthesisand degradation of the extracellular matrix of the degenerative intervertebral disc.Results The shape and function of the normal intervertebral disc were reported to be closely related to the synthesis and degradation of the extracellular matrix of the intervertebral disc. The extracellular matrix of the intervertebral disc was a target for the gene transduction to repair the degenerative intervertebral disc. There was a great development of the treatment with gene transduction, especially in vector choice, target gene transduction, and transgene regulation and safety. Conclusion The advances of the research have indicated that repair of the degenerative intervertebral disc with gene transduction is a keyto curing the disease of the degenerative intervertebral disc.
Small intestinal submucosa (SIS) is a natural decellularized extracellular matrix material. Due to its excellent biocompatibility, unique biomechanical properties and biological activity, it has been widely used as a scaffold in regenerative medicine. This article reviews the recent progress in the characterization and medical application of SIS respectively. The specific biological properties of the SIS, as well as its interaction with cells, are highlighted. Some of the SIS products and clinical cases are also reviewed and discussed.
ObjectiveTo study the feasibility of acellular matrix materials prepared from deer antler cartilage and its biological compatibility so as to search for a new member of the extracellular matrix family for cartilage regeneration. MethodsThe deer antler mesenchymal (M) layer tissue was harvested and treated through decellular process to prepare M layer acellular matrix; histologic observation and detection of M layer acellular matrix DNA content were carried out. The antler stem cells [antlerogenic periosteum (AP) cells] at 2nd passage were labelled by fluorescent stains and by PKH26. Subsequently, the M layer acellular matrix and the AP cells at 2nd passage were co-cultured for 7 days; then the samples were transplanted into nude mice to study the tissue compatibility of M layer acellular matrix in the living animals. ResultsHE and DAPI staining confirmed that the M layer acellular matrix did not contain nucleus; the DNA content of the M layer acellular matrix was (19.367±5.254) ng/mg, which was significantly lower than that of the normal M layer tissue [(3 805.500±519.119) ng/mg](t=12.630, P=0.000). In vitro co-culture experiments showed that AP cells could adhere to or even embedded in the M layer acellular matrix. Nude mice transplantation experiments showed that the introduced AP cells could proliferate and induce angiogenesis in the M layer acellular matrix. ConclusionThe deer antler cartilage acellular matrix is successfully prepared. The M layer acellular matrix is suitable for adhesion and proliferation of AP cells in vitro and in vivo, and it has the function of stimulating angiogenesis. This model for deer antler cartilage acellular matrix can be applied in cartilage tissue engineering in the future.
ObjectiveTo review the progress of cell sheet technology (CST) and its application in bone tissue engineering. MethodsThe literature concerning CST and its application was extensively reviewed and analyzed. ResultsCST using temperature-responsive culture dishes is applied to avoid the shortcomings of traditional tissue engineering. All cultured cells are harvested as intact sheets along with their deposited extracellular matrix. Avoiding the use of proteolytic enzymes, cell sheet composed of the cells and extracellular matrix derived from the cells, and remained the relative protein and biological activity factors. Consequently, cell sheet can provide a suitable microenvironment for the bone regeneration in vivo. With CST, cell sheet engineering is allowed for tissue regeneration by the creation of three-dimensional structures via the layering of individual cell sheets, be created by wrapping scaffold with cell sheets, or be created by folding the cell sheets, showing great potential in tissue engineered bone. ConclusionConstructing tissue engineered bone using CST and traditional method of bone tissue engineering will promote the development of the bone tissue engineering.
Objective To evaluate an effect of the vascularendothelial growth factor (VEGF) geneactivated matrix (GAM) on repair of the sciatic nerve defect in rats. Methods The peripheral nerve extracellular matrix（ECM） was harvested by the chemical extraction from 30 SD rats. The VEGF-GAM comprised of ECM and the plasmids encoding VEGF. Thirty adult Wistar rats were made as a model of the asciatic nerve defect and were randomly divided into the following 3 groups(n=10): Group A (VEGF-GAM conduits), Group B (ECM conduits),and Group C (autografts). At 12 weeks, the rats from each groupwere subjected to an inspection for the walking tract analysis and electrophysiological and histomorphological studies.Results The VEGF DNA could be retained in GAM, promoting the transgene expressing in the sciatic nerve, and more importantly, in the axotomized neurons in the spinal cord for 12 weeks. The motor neuron recovery rate in Group A (79.13％±2.53％) was similar to that in Group C (75.26％±4.48％, Pgt;0.05), but significantly better than that in Group B (56.09％±1.89％, Plt;0.01). The number of the regenerationaxons in the distal sciatic nerve in Group A (13 463±794/mm2) was significantly lower than that in Group C (16 809±680/mm2, Plt; 0.01), but significantly higher than that in Group B (10 260±1 117/mm2,Plt;0.01). The motor nerve conduction velocity in Group A (16.44±1.65 m/s) was significantly lowerthan that in Group C (23.79±2.75 m/s, Plt;0.01), but significantly higherthan that in Group B (12.8 ±1.42 m/s, Plt;0.01). The recovery rate of thegastrocnemius muscle wet weight in Group A (71.40％±3.05%) was significantlylower than that in Group C (87.00％±1.87％,Plt;0.01), but significantly higher than that in Group B (50.00％±4.90％, Plt;0.01). The sciatic nerve function index in Group A （39.37%±4.81%） was significantly lower 〖KG6〗than that in Group C (26.27%±2.71%, Plt;0.01), but significantly higher than that in Group B (4693％±296％, Plt;0.01). Conclusion The results indicate that VEGF-GAM as a bridge can promote the functional recovery of the defected sciatic nerve in rats, but the effect is not so good as that by autografts.
Objective To investigate the expression of neutrophil gelatinase-associated lipocalin (NGAL) signaling pathways in the early stage of porcine vein graft restenosis, and to explore the possible role and mechanism in the early vein graftrestenosis after coronary artery bypass surgery. Methods We selected 18 ordinary healthy pigs weighing 25-30 kg and collected samples of the vein graft of pigs at the preoperation and postoperative days 7, 14 and 30. Hematoxylin-eosin (HE) staining and Masson staining, immunohistochemical method were used to observe the neointimal hyperplasia, the migration of smooth muscle cells and and vascular remodeling of the vein bypass graft. The expression changes of NGAL, matrix metalloprotenase (MMP)9, MMP2 and tissue inhibitor of metalloproteinase (TIMP)1 in different periods of the vein bypass graft was tested. Results By HE and Masson staining, with the passing of modeling time, degradation of collagen matrix in the vein graft, gradually thickening of muscle fibers and the migration to the inner membrance and vascular remodeling caused the vascular stenosis. By immunohistochemistry, NGAL, MMP9 and MMP2 of normal vein in the model were seldom expressed and even did not express. At 14 days after the modeling, NGAL expression in the membrane layer of blood vessels began to appear, peaked at postoperative 30 days, and began to appear in the inner membrance. MMP9, MMP2 expression began to appear at postoperative 7 days, peaked at postoperative 14 days, and tended to decline at postoperative 30 days. TIMP1 expression was less in normal vascular walls and at the 14 days after the modeling, expression peaked in the vein graft. Conclusion NGAL, MMP9, MMP2 and TIMP1 may be involved in the formation of early vascular graft restenosis. NGAL as initiator, results in the expression of MMP9 and MMP2, and participates in the degradation of collagen matrix and the migration of smooth muscle cells in vein grafts. TIMP1 as a negative factor, may play an important role in maintaining their own balance.
Objective To explore the advance in physical materials,chemical matrix, and biological seed cells for fabricating artificial nerve. Methods Recent literature relevant to artificial nerve, especially the achievement in physical material, chemical matrix and biological seed cells for fabricating artificial nerve, were extensively reviewed. Results Polymers of polylactic acid or polyglycolic acid and their polymer, polymer of hyaluronic acid and glut-aldehyde, polymer of polyacrylonitrile and polyvinylchloride were artificial nerve materials with the properties of good biocompatibility and biodegradation. A conduit with multichannel and high percentage of pores was beneficial to the regeneration of nerve. The activated Schwann cells were excellent seeds of artificial nerve. A suitable chemical matrix, such as laminin and alginate, could promote the regeneration of nerve. Conclusion The successful fabrication of artificial nerve lies in the advance in the mechanism of nerve regeneration and physical material, chemical matrix and biological seed cells.
ObjectiveThe tissue engineered osteochondral integration of multi-layered scaffold was prepared and the related mechanical properties and biological properties were evaluated to provide a new technique and method for the repair and regeneration of osteochondral defect.MethodsAccording to blend of different components and proportion of acellular cartilage extracellular matrix of pig, nano-hydroxyapatite, and alginate, the osteochondral integration of multi-layered scaffold was prepared by using freeze-drying and physical and chemical cross-linking technology. The cartilage layer was consisted of acellular cartilage extracellular matrix; the middle layer was consisted of acellular cartilage extracellular matrix and alginate; and the bone layer was consisted of nano-hydroxyapatite, alginate, and acellular cartilage extracellular matrix. The biological and mechanics characteristic of the osteochondral integration of multi-layered scaffold were evaluated by morphology observation, scanning electron microscope observation, Micro-CT observation, porosity and pore size determination, water absorption capacity determination, mechanical testing (compression modulus and layer adhesive strength), biocompatibility testing [L929 cell proliferation on scaffold assessed by MTT assay, and growth of green fluorescent protein (GFP)-labeled Sprague Dawley rats’ bone marrow mesenchumal stem cells (BMSCs) on scaffolds].ResultsGross observation and Micro-CT observation showed that the scaffolds were closely integrated with each other without obvious discontinuities and separation. Scanning electron microscope showed that the structure of the bone layer was relatively dense, while the structure of the middle layer and the cartilage layer was relatively loose. The pore structures in the layers were connected to each other and all had the multi-dimensional characteristics. The porosity of cartilage layer, middle layer, and bone layer of the scaffolds were 93.55%±2.90%, 93.55%±4.10%, and 50.28%±3.20%, respectively; the porosity of the bone layer was significantly lower than that of cartilage layer and middle layer (P<0.05), but no significant difference was found between cartilage layer and middle layer (P>0.05). The pore size of the three layers were (239.66±35.28), (153.24±19.78), and (82.72±16.94) μm, respectively, showing significant differences between layers (P<0.05). The hydrophilic of the three layers were (15.14±3.15), (13.65±2.98), and (5.32±1.87) mL/g, respectively; the hydrophilic of the bone layer was significantly lower than that of cartilage layer and middle layer (P<0.05), but no significant difference was found between cartilage layer and middle layer (P>0.05). The compression modulus of the three layers were (51.36±13.25), (47.93±12.74), and (155.18±19.62) kPa, respectively; and compression modulus of the bone layer was significantly higher than that of cartilage layer and middle layer (P<0.05), but no significant difference was found between cartilage layer and middle layer (P>0.05). The osteochondral integration of multi-layered scaffold was tightly bonded with each layer. The layer adhesive strength between the cartilage layer and the middle layer was (18.21±5.16) kPa, and the layer adhesive strength between the middle layer and the bone layer was (16.73±6.38) kPa, showing no significant difference (t=0.637, P=0.537). MTT assay showed that L929 cells grew well on the scaffolds, indicating no scaffold cytotoxicity. GFP-labeled rat BMSCs grew evenly on the scaffolds, indicating scaffold has excellent biocompatibility.ConclusionThe advantages of three layers which have different performance of the tissue engineered osteochondral integration of multi-layered scaffold is achieved double biomimetics of structure and composition, lays a foundation for further research of animal in vivo experiment, meanwhile, as an advanced and potential strategy for osteochondral defect repair.
OBJECTIVE: To investigate the selection and manufacture of ideal extracellular matrix materials in bone tissue engineering. METHODS: The recent literatures about biodegradable polymers served as culture scaffolds of osteoblasts were widely reviewed, the advantages and disadvantages of biodegradable synthetic polymers and natural polymers were analysed. RESULTS: The ideal extracellular matrix material in bone tissue engineering should be made up of inorganic materials, synthetic polymers and natural polymers, which possesses morphological structure of three-dimensional foam with self-mediated drug slow delivery system of bone growth factors. CONCLUSION: The design and manufacture of combined extracellular matrix materials in bone tissue engineering is a very important and urgent challenge.
ObjectiveTo summarize the regulating mechanism of microRNA in tumor microenvironment. MethodThe literatures about the studies on the mechanism regulated by microRNA for tumor microenvironment were reviewed according to the results searched from PubMed in recent years. ResultsmicroRNA might be participated in regulation of tumor microenvironment factors such as hypoxia-inducible factor, tumor associated fibroblasts, extracellular matrix, which leaded to a change in biological behavior of tumor cells by reforming the microenviroment. ConclusionsmicroRNA has been participated in regulating many factors of tumor microenvironment. The change of neoplastic microenvironment has been recognized to play a critical role in the development of cancer. Therefore revealing microRNA mechanism for tumor microenvironment could not only help exploring the biological behavior of tumor cells, but also come an important insight for new means of diagnosis and treatment of cancer.