Tehran University Medical Journal

Stem cells are undifferentiated and multi pluripotent cells which can differentiate into a variety of mature cells and tissues such as nervous tissue, muscle tissue, epithelial tissue, skeletal tissue and etc. Stem cells from all different source have three unique features: 1) Proliferative capability: Stem cells are capable of self dividing and self renewing for long periods or more than six months at least that called immortalization. 2) Undifferentiated nature: It’s considered as one of the essential characteristics of stem cell, so it doesn't have any tissue-specific construction. 3) Differentiation to the different cells from all organs: This ability can Induced by tissue specific transcription factors. Because of that, they are so important in prevention and treatment of human disease. Depending on the sources from which they derive, they have different types which can be used to produce special cells and tissues. The most significant types of stem cells are; embryonic stem cells (ESCs) which are derived from embryos, adult stem cells (ASCs) which are derived from differentiated cells in a specific tissue, induced pluripotent stem cells (iPSs) which are produced from adult differentiated cells that have been genetically reprogrammed to act resemble to an embryonic stem cell and cord blood stem cells which contains haematopoietic stem cells and derived from the umbilical cord after gestation. By providing a medium containing of special growth factor, it is possible to orientated stem cell differentiation pathway and gained certain cells from them. The important uses of stem cells includes damaged heart tissue cells improvements and bone tissue repairing, cancer treatment, damaged neurological and spinal tissue repairing, improving burns and injuries and the treatment of diabetes, infertility and spermatogenesis dysfunction. Furthermore, the application of them in gene therapy is an important issue in the modern medicine science due to the role of them in transferring gene into different cells. Today, this method have had considerable progress in the treatment of many disease. In this review study, some aspect of stem cells like types and characteristic, origin, derivation techniques, storage conditions and differentiation to target tissues, current clinical usage and their therapeutic capabilities will be discussed.