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 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.
Objective To investigate the research development of the liver stem cell(LSC) and to predict its future application. Methods Based on our own researches and combined with the review of the related literature at home and abroad, we analyzed and evaluated the latest development of the research on the LSC. Results We knew the differentiation and proliferation of the LSC towards some kinds of specified cells were affected by many factors; and the researches on the LSC in regard to its activation, isolating culture, bolting, and evaluation still needed further improvements. Conclusion With the development of the research, the liver stem cell can become a new seed cell to cure some liver diseases.
Objective To review the current development in meniscus tissue engineering. Methods Recent literature concerning the development of the meniscus tissue engineering was extensively reviewed and summarized. Results Recent researches mainly focus on: selection of seed cells and research of their potential of differentiation into chondrocytes; selection of scaffold materials and research of their mechanical properties; cytokines and their mechanisms of action. Conclusion Many achievements have been made in meniscus tissue engineering. Most important topics in future research include: finding seed cells that are adapted to physiological process, are easy to culture, and have higher chondrogenic differentiation ability; looking for necessary cytokines and their mechanisms of action; finding scaffold meterials with b morphological plasticity, no antigenicity, good degradability, and mechanical property close to normal meniscus.
ObjectiveTo review the current progresses in purification strategies, biological characters, and the uses in tissue engineering of urine-derived stem cells (USCs). MethodsRecent relevant publications on the USCs were extensively reviewed, analyzed, and summarized. ResultsUSCs, usually isolated by adherence screening method, are a population of mesenchymal stem cells (MSCs)-like somatic stem cells possessing robust self-renew and multi-potential differentiation ability. Combined with using appropriate biomaterials and biological molecules, USCs can be used as a good cell source for tissue engineering. ConclusionAn alluring prospect exists on the USCs-related research. Further studies are required to investigate the origin, individual differences, and the therapeutic values of USCs.
To serve as carriers of cells and bioactive molecules, three-dimensional scaffolds play a key role in bone defect repair. The chemical component and microstructure of the scaffold can affect the mechanical properties and seed cells. A variety of fabrication techniques have been used in producing scaffolds, some made random porous structure, some created well-designed structure using rapid prototyping methods, and others prepared bio-derived materials as scaffolds. However, scaffolds may vary in their inner structure, mechanical properties and repairing efficiency as well because of different manufacturing methods. In this review, we overview the main achievements concerning the effects of material and microstructure on the mechanical performance, seed cells and defect repair of bone scaffolds.
ObjectiveTo explore the morphological and functional features of tissue engineered composite constructed with bone mesenchymal stem cells (BMSCs) as seeding cells, thermosensitive collagen hydrogel (TCH) and poly-L-lactic acid (PLLA) as the extracellular matrix (ECM) scaffolds in the dynamic culture system. MethodsBMSCs were separated from long bones of Fischer344 rat, and cultured; and BMSCs at the 3rd generation were seeded on the ECM scaffold constructed with braided PLLA fiber and TCH. The BMSCs-ECM scaffold composite was cultured in the dynamic culture system which was designed by using an oscillating device at a frequency of 0.5 Hz and at swing angle of 70° (experimental group), and in the static culture system (control group) for 7 days. The general observation and scanning electron microscopy (SEM) observation were performed; total DNA content was measured at 0, 1, 3, and 7 days. ResultsPLLA was surrounded by collagen to form translucent gelatiniform in 2 groups; and compact membrane developed on the surface of PLLA. SEM observation showed that BMSCs had high viability and were fusiform in shape with microvilli on the surface of cells, and arranged in line; collagen and cells filled in the pores of PLLA fiber in the experimental group. The cells displayed a flat shape on the surface; there were less cells filling in the pores of PLLA fiber in the control group. At 1, 3, and 7 days, total DNA content in the experimental group was significantly higher than that in control group (P < 0.05). The total DNA content were increased gradually with time in 2 groups, showing significant difference between at 0 day and at 7 days (P < 0.05). ConclusionThe ECM constructed with TCH and PLLA has good biocompatibility. The dynamic cultivation system can promote the cell proliferation, distribution, and alignment on the surface of the composite, so it can be used for tissue engineered composite in vitro.
ObjectiveTo summarize the research progress of tissue engineered bile duct in recent years.MethodsThis paper summarized recently-published papers related to tissue-engineered bile duct on in vitro test platform, scaffold materials, acquisition methods of seed cells, and in vivo repair effectiveness after the fusion of seed cells and materials, in an attempt to review the basic and clinical application studies of tissue-engineered bile duct.ResultsTissue-engineered bile duct had been developing rapidly. At present, great progress had been made in the fields of in vitro test platform, scaffold materials, seed cells, and repair effectiveness in animal models. However, further study was still needed in terms of its clinical application. The external bile duct platform included 3D printing and biological simulation; in the aspect of scaffold material, apart from the progress of various artificial materials, acellular matrix was introduced; the selection of seed cells included the induction and differentiation of bile duct-derived stem cells, human bone marrow mesenchymal stem cells (hMSCs), hepatic oval cell (HOC), pluripotent stem cells (PSCs), and other stem cells; animal models of tissue-engineered bile ducts had also achieved good results in animals such as pigs and dogs.ConclusionThe development of tissue-engineered bile duct will promote the progress of fundamental in vitro studies on extrahepatic biliary tract diseases, thus introducing new options to the clinical treatment of extrahepatic biliary tract injuries.
Seeding cells play an important role in the peripheral nerve damage repair. Seeding cells studied consequently in peripheral nerve are Schwann cells, bone marrow mesenchymal stem cells and neural stem cells. Schwann cells, the first seeding cells, are various unique glial cells in the peripheral nervous system, which can form the myelin sheath for insulation and package of the neuron projecting axons in the peripheral nervous system so that the conduction velocity of the nerve signal was accelerated. It can be proved that Schwann cells played an important role in the maintenance of peripheral nerve function and in the regeneration process after peripheral nerve injury. The second, bone marrow mesenchymal stem cells are the various mesenchymal stem cells mainly exist in the systemic connective tissues and organs. These functional stem cells are often studied at present, and it has been found that they have exuberant proliferation and differentiation potentials. Neural stem cells, mentioned the third in sequence, are the kind of pluripotent cells with multi-directional differentiation, which could conduct the self-renewal function, and generate and differentiate neurons, astrocytes and oligodendrocytes through asymmetric cell division. These three types of seed cells are discussed in this paper.
ObjectiveTo summarize the research progress of tissue-engineered bile duct in recent years. MethodsThe related literatures about the tissue-engineered bile duct were reviewed. ResultsIn recent years, the research of tissue-engineered bile duct has made a breakthrough in scaffold materials, seed cells, growth factors etc. However, the tissue-engineered bile duct is still in the research stage of animal experiments, which can not be directly applied to clinical practice. ConclusionsThe research of tissue-engineered bile duct becomes popular at present. With the rapid development of materials science and cell biology, the basic research and clinical application of tissue-engineered duct will be more in-depth research and extension, which might bring new ideas and therapeutic measures for patients with biliary defect or stenosis.