tailieunhanh - Chapter 067. Applications of Stem Cell Biology in Clinical Medicine

Organ damage and the resultant inflammatory responses initiate a series of repair processes, including stem cell proliferation, migration, and differentiation, often in combination with angiogenesis and remodeling of the extracellular matrix. Endogenous stem cells in tissues such as liver and skin have a remarkable ability to regenerate the organs, whereas heart and brain have a much more limited capability for self-repair. Under rare circumstances, circulating stem cells may contribute to regenerative responses by migrating into a tissue and differentiating into organ-specific cell types. . | Chapter 067. Applications of Stem Cell Biology in Clinical Medicine Organ damage and the resultant inflammatory responses initiate a series of repair processes including stem cell proliferation migration and differentiation often in combination with angiogenesis and remodeling of the extracellular matrix. Endogenous stem cells in tissues such as liver and skin have a remarkable ability to regenerate the organs whereas heart and brain have a much more limited capability for self-repair. Under rare circumstances circulating stem cells may contribute to regenerative responses by migrating into a tissue and differentiating into organ-specific cell types. The goal of stem cell therapies is to promote cell replacement in organs that are damaged beyond their ability for self-repair. Sources of Stem Cells for Tissue Repair Different types of stem cells include embryonic stem ES cells umbilical cord blood stem cells organ-specific somatic stem cells . neural stem cells for treatment of the brain and somatic stem cells capable of generating cell types specific for the target rather than the donor organ . bone marrow mesenchymal stem cells for cardiac repair Chap. 66 . ES cells self-renew endlessly so that a single cell line with carefully characterized traits can generate large numbers of cells that can be immunologically matched with potential transplant recipients. However little is currently known about the mechanisms that govern differentiation of these cells or processes that limit their unbridled proliferation. Human ES cells are difficult to culture and grow slowly. ES cells tend to develop abnormal karyotypes and have the potential to form teratomas if they are not committed to the desired cell types before transplantation. The study of human ES cells has been controversial and their use in clinical applications would be unacceptable to some patients and physicians despite their enormous potential. Somatic cell nuclear transfer quot therapeutic cloning quot .