ObjectiveTo review the research progress of the role of seed cells and related cytokines in angiogenesis of the vascularized tissue engineered bone. MethodsThe latest literature of tissue engineered bone angiogenesis was reviewed, including the common source of seed cells, biological characteristics, transformation mechanism, related cytokines, and signaling pathways in re-vascularization. ResultsMicrosurgery technique, genetic technique, and co-culture system of vascularized tissue engineered bone have developed to a new level. Moreover, both the induction of introduced pluripotent stem cells and vascular endothelial growth factor-angiopoietins 1 transfected mesenchymal stem cells and endothelial progenitor cells have some advantages for bone regeneration and vascularization. However, all the techniques were not used in clinical practice. ConclusionUsing techniques of genetically modified seed cells, related cytokines, and scaffolds may have bright prospects for building vascularized tissue engineered bone.
Objective To elucidate the latest research progress and application of tissue engineered meniscus. Methods The literature concerning the advance in tissue engineered meniscus was extensively reviewed, then closely-related issues including seed cells, scaffolds, and bioreactors were analyzed. Results With more and more attention being paid to meniscus tissue engineering, different approaches and strategies for seed cells, scaffolds, and bioreactors have contributed to the generation of meniscal constructs, which are capable of restoring meniscal lesions to some extent, but translating successes in basic science research to clinical application is still limited. Conclusion More research for the optimal combination of the appropriate cell source, the scaffold type, and the proper physical and chemical factors for the stimulation of cells differentiation into tissue with optimal phenotypes in tissue engineered meniscus is still in needed, but the overall future looks promising.
Objective To review the research progress of cell-scaffold complex in the tendon tissue engineering. Methods Recent literature concerning cell-scaffold complex in the tendon tissue engineering was reviewed, the research situation of the cell-scaffold complex was elaborated in the aspects of seed cells, scaffolds, cell culture, and application. Results In tendon tissue engineering, a cell-scaffold complex is built by appropriate seed cells and engineered scaffolds. Experiments showed that modified seed cells had better therapeutic effects. Further, scaffold functionality could be improved through surface modification, growth factor cure, mechanical stimulation, and contact guidance. Among these methods, mechanical stimulation revealed the most significant results in promoting cell proliferation and function. Through a variety of defect models, it is demonstrated that the use of cell-scaffold complex could achieve satisfactory results for tendon regeneration. Conclusion The cell-scaffold complex for tendon tissue engineering is a popular research topic. Although it has not yet met the requirement of clinical use, it has broad application prospects.
Objective To establ ish an efficient and stable culture method of human umbil ical vein endothel ial cells (HUVECs) in vitro so as to provide good source of seed cells for tissue engineered vascular grafts and for precl inical research. Methods The umbil ical cords were harvested from full-term normal delivered neonates, which were perfused with0.1% collagenase II by self-made needle and were digested at 37 and 5% CO2 humidified incubator. The HUVECs were cultured in endothel ial culture medium (ECM) containing 5% fetal bovine serum (FBS) and 1% endothel ial cell growth factor (ECGS). HE staining of the umbil ical cords before and after digestion was used to observe the detachment of HUVECs, flow cytometry to detect the purity of primary HUVECs, and inverted phase contrast microscope to observe the morphology of the cultured HUVECs. The growth of the 3rd passage cells was measured by MTT assay; immunocytochemical technique and matrigelbased capillary-l ike tube formation assay were carried out to identify the function of HUVECs. Results After digestion of 0.1% collagenase II, marked HUVECs detachment was observed with complete digestion. The purity of the HUVECs was 99.56% by digestion of 0.1% collagenase II at 37 and 5% CO2 humidified incubator for 15 minutes. Primary HUVECs showed a cobblestone or pitching stone-l ike appearance in vitro, forming a confluent monolayer cells after 2-3 days of culture. MTT assay demonstrated that HUVECs showed the fastest growth speed at 3 to 4 days, and showed growth of cell fusion at about 5 days. Immunocytochemistry showed that HUVECs highly expressed endothel ial marker factor VIII. Matrigel based capillary-l ike tube formation assay showed that it could form endothel ial-l ike tube structures after 24 hours of culture. Conclusion Using improved method and ECM could obtain high quantity and high qual ity primary HUVECs, which might be a kind of promising seed cells for tissue engineering and precl inical research.
Objective To review the research status of the neovascularization of adi pose tissue engineering in the past decade so as to provide theoretical references for the development of the rapid revascularization of tissue engineered adi pose. Methods The l iterature about the revascularization of adi pose tissue engineering was extensively reviewed andanalyzed, centering on 5 elements: specificity of histological structures and blood supply, revascularization mechanism, coculture of different seed cells, modification of scaffold, and microenvironment. Results Adi pose tissue engineering offers a new solution for soft tissue defects. However, there is still the unfulfilled need in the size of engineered adipose tissue (less than 1 mL), which was determined by the degree of neovascularization in engineered tissue. Overall, rapid neovascularization in engineering tissue is a key l ink of experimental study changing into cl inical appl ication. Conclusion Providing a sufficient supply with nutrients and oxygen by means of a sufficient and rapid neovascularization will be at the heart of any attempts to obtain bigger tissue engineered adipose to meet the demand of repairing large soft tissue defect.
Objective To review new progress of related research of peri pheral nerve defect treatment with tissue engineering in recent years. Methods Domestic and internationl l iterature concerning peri pheral nerve defect treatment with tissue engineering was reviewed and analyzed. Results Releasing neurotrophic factors with sustained release technology included molecular biology techniques, poly (lactic-co-glycol ic acid) microspheres, and polyphosphate microspheres. The mixture of neurotrophic factors and ductus was implanted to the neural tube wall which could be degraded then releasing factors slowly. Seed cells which were the major source of active ingredients played an important role in the repair and reconstruction of tissue engineering products. The neural tube of Schwann cells made long nerve repair and the quality of nerve regeneration was improved. Nerve scaffold materials included natural and synthetic biodegradable materials. Tube structure usually was adopted for nerve scaffold, which performance would affect the nerve repair effects directly. Conclusion With the further research of tissue engineering, the treatment of peripheral nerve defects with tissue engineering has made significant progress.
Objective To study the effect of hypoxia on the prol iferation of hBMSCs and human placental decidua basal is-MSCs (hPDB-MSCs), and to provide the theoretical basis for discovering the new seed cells source for tissue engineering. Methods Density gradient centrifugation method was adopted to isolate and culture hBMSCs and hPDB-MSCs,flow cytometry (FCM) was appl ied to detect cell surface marker. After establ ishing the experimental model of CoC12 chemical hypoxia, MTT method was appl ied to evaluate the prol iferation of hBMSCs and hPDB-MSCs at different time points (6, 12, 24, 48, 72, 96 hours) with various CoC12 concentration (0, 50, 75, 100, 125, 150, 175, 200 μmol/L). Results FCM analysis revealed that hPDB-MSCs and hBMSCs expressed CD9, CD29, CD44, CD105, CD106 and human leucocyte antigen ABC (HLA-ABC), but both were absent for CD34, CD40L and HLA-DR. Compared with hBMSCs, hPDB-MSCs expressed stage-specific embryonic antigen 1 (SSEA-1), SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81 better. The prol iferations of hPDB-MSCs and hBMSCs were inhibited within the first 12 hours under hypoxia condition, but promoted after 12 hours of hypoxia. Compared with the control group, the hBMSCs were remarkably prol iferated 24 hours after hypoxia with CoC12 concentration of 150 µmol/L (P lt; 0.05), while hPDB-MSCs were significantly prol iferated 12 hours after hypoxia with CoC12 concentration of 75 µmol/L (P lt; 0.05). Conclusion Compared with hBMSCs, hPDB-MSCs express more specific surface antigens of embryonic stem cells and are more sensitive to the prol iferation effects of chemical hypoxia, indicating it may be a new seed cells source for tissue engineering.
Objective To investigate an important role of the stem cells in reconstructing the tissues and organs. Methods Based on our own researches and combined with the review of the literature at home andabroad, the latest development of the cell therapy with the stem cells and the application of the seed cells in the tissue engineering were analyzed. Results As the stem cells are the origin of the human tissues and organs and have a higher self-renewal ability and extensive characteristics of proliferation in vitro, their imbedding and multi-differential potentialities were illustrated. Both the embryonic stem cells and the adult stem cells had a wide prospect as ideal seed cells for reparation and reconstruction of the impaired human tissues and organs. Conclusion The stem cells can play animportant role in repairing and reconstructing the injured tissues and organs and they have a promising prospect in clinical application. The further research and wide application of the stems cells will significantly improve the therapeutic effects on the injured tissues and organs.
ObjectiveTo comprehensively analyze and compare the biological difference between bone marrow mesenchymal stem cells (BMSCs) and placenta-derived MSCs (PMSCs) in hypoxia and to extend the knowledge for seed cells selection. MethodsThe domestic and foreign related literature about the effects of hypoxia microenvironment on proliferation, apoptosis, differentiation, paracrine secretion, migration, and homing ability of BMSCs and PMSCs were summarized and analysed. ResultsPMSCs proliferated much faster and more sensitive to the hypoxia than BMSCs; in addition, PMSCs showed stronger survivability. Similar to BMSCs, PMSCs can home to hypoxic-ischemic tissues efficiently, secrete a lot of growth factors and differentiate into tissue-specific cells to stimulate tissue regeneration. ConclusionPMSCs as the seed cells will have broad application prospects in the regenerative medicine.
ObjectiveTo study the potential protective effects of bone marrow mesenchymal stem cells (BMSCs) on chondrocytes injured by interleukin 1β (IL-1β), and the resistant capacity of chondrocytes when co-cultured indirectly with BMSCs against IL-1β. MethodsSix Sprague Dawley (SD) rats were randomly divided into experimental group (articular cartilage defects) and control group. The content and gene expression of IL-1β were detected at 6 hours after surgical intervention by quantitative real time RCR (qRT-PCR) and ELISA. BMSCs repairing function test: the 18-holes cultured chondrocytes were randomly divided into 3 groups (n=6): cells of blank group were not treated;cells of injured group and co-cultured group were intervened by IL-1β, and Transwell chamber was used to establish co-culture system of BMSCs with chondrocyte in co-cultured group. The mRNA relative expressions of cysteinyl aspartate specific proteinase 3 (Caspase 3), a disintegrin and metalloprotease with Thrombospondin motifs 4 (ADAMTS-4), and ADAMTS-5 were measured via qRT-PCR in chondrocytes, meanwhile Caspase-3 content was detected via ELISA, and the cell apoptosis rate was detected via flow cytometry. BMSCs protecting function test: the 12-holes cultured chondrocytes were randomly divided into 2 groups (n=6), Transwell chamber was used to establish co-culture system of BMSCs with chondrocyte in co-cultured group before the 2 groups were both intervened by IL-1β, then the same detected indexes were taken as the BMSCs repairing function test. ResultsAnimal in vivo studies showed that relative expression of IL-1β mRNA and IL-1β contents were significantly higher in experimental group than control group (P<0.05). BMSCs repair tests showed that mRNA relative expressions of Caspase-3, ADAMTS-4, and ADAMTS-5, Caspase-3 content, and cell apoptosis rate were significantly higher in injured group and co-cultured group than blank group, and in injured group than co-cultured group (P<0.05). BMSCs protect tests showed that mRNA relative expressions of Caspase-3, ADAMTS-4, and ADAMTS-5, Caspase-3 content, and cell apoptosis rate in co-cultured group were significantly lower than those in control group (P<0.05). ConclusionBMSCs, as seed cells for tissue engineering, have potential for applications to anti-inflammation and anti-apoptosis.