CHIMERA (n): A SINGLE ORGANISM CONSISTING OF GENETICALLY DISTINCT CELLS.
QUIMERA (SPANISH): A BEAUTIFUL DREAM
What are Stem Cells?
Stem cells have the extraordinary capability to develop into many different cell types in the body during early life and growth. In addition, in many tissues they serve as a sort of internal repair mechanism, dividing essentially without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential either to remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.
Stem cells are distinguished from other cell types by two important characteristics. First, they are unspecialized, resting (quiescent) cells capable of renewing themselves through cell division, sometimes after long periods of inactivity. Second, under certain physiologic or experimental conditions, they can be induced to become tissue- or organ-specific cells with special functions. In some organs, such as the gut and bone marrow, stem cells regularly divide to repair and replace worn out or damaged tissues. In other organs, however, such as the pancreas and the heart, stem cells only divide under special conditions, or with the appropriate stimulation.
Believe it or not 'stem cell' procedures have been performed since the 1950's and were pioneered by physicians like E. Donall Thomas. These Bone Marrow Transplants currently provide life-saving treatments for patients with leukemia, lymphoma, other blood disorders, and some solid tumors. The three main technologies in use today are:
Adult stem cell transplant: bone marrow stem cells
The patient’s bone marrow stem cells are replaced with those from a healthy, matching donor. If the transplant is successful, the stem cells will migrate into the patient’s bone marrow and begin producing new, healthy leukocytes to replace the abnormal cells.
Adult stem cell transplant: peripheral blood stem cells (PBSCs)
PBSCs can be obtained from drawn blood, making them easier to collect than bone marrow stem cells. However, PBSCs are sparse in the bloodstream, so collecting enough to perform a transplant can pose a challenge.
Umbilical cord blood stem cell transplant
The stem-cell-rich blood found in the umbilical cord has proven useful in treating the same types of health problems as those treated using bone marrow stem cells and PBSCs.