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Abstract Throughout the past decades, organ transplantation helped victims of liver. But this procedures is accompanied with numerous problems as the demand is far greater than the supply, no enough organs are available for patients in need, patients die while waiting, and also, rejection and destruction of transplanted liver in addition to high cost of this procedure makes it unavailable for large sector of patients. Add to this, a lot of complications accompanied with the use of immunosuppressive medications rendering patients susceptible to viral, bacterial diseases as well as cancer and the extremely heavy costs for the remainder of their lives. So, with availability of a minimally invasive approaches, stem cell therapy has recently reffered to be regenerative medicine provides much promise for the treatment of what was previously regarded as incurable diseases. In 1960 fiest few cases of successful of stem cell of bone marrow origin in treatment of congential Immune deficiency disorder and end stage leukemia were reported. Summary and conclusion 181 Stem cells are one of most fascinating areas of biology today. But like many expanding fields of scientific inquiry, research on stem cells raises scientific questions as rapidly as it generates new research on stem cells is advancing knowledge about how an organism develops from a single cell and how healthy cells replace damaged cells in adult organisms. This promising area of science is also leading scientists to investigate the possibility of cell- Based therapies to treat disease, which is often referred to as regenerative or reparative medicine. Stem cells have two important characters that listing distinguish them from other types of cells. First, they aer unspecialiazed cells that renew themselves for long periods through cell division. The Second is that under certain physiologic or experimental conditions,they can be induced to become cells with special functions such as beating cells of heart muscles or the insulin producing cells of the pancreas. In this literature we focused on the sources of the stem cells which indicated in liver diseases therapy, the power of it to regenerate and repopulate liver tissues and how to Summary and conclusion 182 investigate stem cell transplantation by imaging techniques and usage of markers to identify stem cells. Until recently the three major sources of stem cells are bone marrow,peripheral blood and cord blood Stem cell. Three are two types of bone marrow stem Cell whether autologous or allogenic stem cell Transplantation. Human embryonic and adult stem cells each have advantages and disadvantages regading potential use for cell based regenerative theoiries. Of course, adult and embryonic stem cells differ in the number and types of differentiated cells types of they can become. Embryonic stem cells can become all Cell types of the body because they are pluripotent. Adult stem cells are generally limited to be Differentiated into different cell of their tissue origin. There are many theories of transdifferentiation Which mean conversion of cells from one differentiate to Hepatocytes. Although the use of stem cells for liver directed cell based therapeutic approaches become very attractive, Summary and conclusion 183 however, the mechanism for regeneration of liver cells by stem cells still controversial. Therefore, the development of appropriate methods of cell transplantation is mandatory in order to improve successful repopulation and tissue engineering approaches for liver therapy by stem cells. To prove that transdifferentiation was occurred we must prove that the cells acquire the new Morphologic and functional and antigenic characters of new organs e.g., transdifferentiation to hepatocytes. The new cells acquire large size and acquire new surface antigen (AFP) and appearance of functional Product in cell culture which was albumin. Transdifferentiation to occur there is induction stage by nuclear transplantation or manipulation of cell culture condition or uptake of molecules from cellular extract or induction of ectropic gene expression. Applications of stem cell for treatment of liver diseases therapies seems to be a promising approach for the treatment of liver diseases; several issues need to be aaressed to fulfill this promise. |