Stem cells

Stem cells are undifferentiated and unspecialized cells that, firstly, have the ability to divide and proliferate for long periods through cell division, and, secondly, under certain physiologic or experimental conditions, they can be induced to become cells with special functions such as neurons or adipocytes.

• embryonic
  stem cells MeSH Cells derived from blastocyst (pre-implantation embryo 5-6 days after fertilization; these are totipotent cells, i.e., cells that have the potential to form an entire organism.
• fetal stem
  cells MeSH Cells derived from a fetus that retain the ability to divide, proliferate and provide progenitor cells that can differentiate into specialized cells.
• embryonic germ cells EG cell; cell derived from a specific part of the fetus (older than 8 weeks of development) called the gonad ridge; germ cells normally develop into eggs and sperm; EG cells similarly to embryonic stem (ES) cells are pluripotent, i.e. can develop into different cell types; unlike them EG cells can only survive about 70 to 80 cell divisions under laboratory conditions.
• umbilical cord
  stem cells Umbilical cord stem cells are stem cells collected from the umbilical cord at birth; normally, the placenta and its contents are discarded after delivery; it has been found that stem cells can be collected from the umbilical cord before the placenta is discarded; its current use is to repair the bone marrow after treatments for cancer, as it is thought that umbilical cord stem cells are mainly haematological precursor cells.
• adult stem
  cells MeSH Also called somatic stem cells; these are undifferentiated cells found among diferentiated cells in a tissue or organ; under certain conditions they can differentiate into major specialized types of the tissue or organ; these cells are multipotent, i.e., they are commited to give rise to cells that have a particular function.
• hematopoietic
  stem cells MeSH Progenitor cells from which all blood cells derive.
  • myeloid progenitor
    cells MeSH Stem cells derived from hematopoietic stem cells. They are multipotent: specialized stem cells that are committed to give rise to cells that have a particular function. Derived from these myeloid progenitor cells are the megakaryocytes, erythroid cells, myeloid cells, and some dendritic cells.
• mesenchymal
  stem cells MeSH Also called bone marrow stromal cells.; Mixed population of cells that can develop into distinct mesenchymal tissue such as bone, tendons, muscles, adipose tissue (fat), cartilage, nerve tissue, and blood and blood vessels.
• neural stem cells These cells give rise too three major cell types in the brain: neurons, astrocytes, and oligodendrocytes.
• tumor stem
  cells MeSH Also called neoplastic stem cells. Colony-forming cells which give rise to neoplasms (tumors). They have properties similar to normal stem cells, i.e., high proliferative and self-renewal capacities. Example: embryonal carcinoma (EC) cells; recent data from both hematologic malignancies and solid tumors have suggested that there are only minor populations of cells in each malignancy that are capable of tumor initiation; these tumor initiating cells have the functional properties of a tumor stem cell; they appear to be capable of asymmetric division and self renewal, and are only a minor faction among the bulk of more differentiated cells in the tumor; these observations have profound implications for tumor biology research as well as successful tumor therapy.

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