tailieunhanh - Tissue Surgery - part 10

Hình 12-2. a) Intraosseous ghép tế bào gốc CD90 và các tế bào tủy xương có nguồn gốc từ tổ tiên như một cách tiếp cận điều trị cấy ghép composite allograft chi. b) người nhận Limb allograft ở 7 ngày posttransplantation sau khi điều trị với CD90 gốc và các tế bào nguyên bản mà không cần suy giảm miễn dịch. | 150 Tissue Surgery adeno-associated viruses can be used to transfer genes into target cells. Adenoviruses allow the production of high virion titers stabilize recombinant virions without helper contamination and have potentially better safety Gene therapy has several disadvantages. Stem cell capability can be easily lost during in vitro manipulation poor engraftment from cultured stem cells has been Moreover hematopoietic progenitor cells from bone marrow lose their stem cell ability more easily than HSCs in peripheral Therefore the difference between stem cells at different stages of development should be considered when designing ther-apeuticstrategies includingexvivomanipulation of Low gene transfer efficiency is still a challenge for human HSCs. The self-renewal frequency of murine HSCs is higher than it is in larger animals so that the cells are expected to divide at least once during a few days of a standard retroviral transduction period. However in larger animals the frequency of self-renewal of HSCs may be much During a transduction period even in the presence of hematopoietic cytokines these cells unlikely cycle and may differentiate or lose their engraftment capabilities. Also human HSCs have far fewer retroviral receptors on their cell surfaces than do murine HSCs which limits the transduction of human Inducing differentiation in gene transfer experiments is important to get mature functional cells however differentiation can also be a problem because true stem cells have to be maintained in vitro. For increasing the rate of homologous recombination new techniques are under development. Recent Advances in Stem Cell Therapy Our knowledge about stem cells is increasing at an incredible rate. By the time you read this chapter there will most probably be some new and very important development about stem cells and their applications. The more we learn about stem cells the more we understand .