Home of blood forming stem cells identified
Although scientists have found ways to produce stem cells and convert them into cells of various types, they were unable to produce blood cells until now, as they were unable to figure out the micro-environment necessary for the hemopoietic stem cells to thrive. However, in a breakthrough study which has been published in the January 26, 2012 issue of the journal Nature, researchers from the Children’s Research Institute at UT South-western Medical Center, have found that the blood forming stem cells reside and grow in the endothelial and perivascular cells lining the blood vessels. With this discovery, it will be easier to identify and comprehend the mechanisms which help in promoting and maintaining the growth of stem cells.
The study was led by Dr. Sean Morrison, the Director of the institute. He, along with his colleagues tried to identify the source of stem cell factor, a protein necessary for the maintenance of the hemopoietic stem cells. The scientists removed the gene responsible for the production of the stem cell factor in mouse and replaced it with a gene from jelly fish. The latter is responsible for the production of a fluorescent green colored protein. The researchers noticed that the endothelial and perivascular cells emitted green light. This helped in identifying them as the source which provides the right environment for the hemopoietic stem cells to grow and multiply. The researchers went a step further and removed stem cell factor from the endothelial and perivascular cells. This led to a depletion and eventual disappearance of the blood forming stem cells.
Once the mechanisms by which the endothelial and perivascular cells promote the growth of blood forming stem cells is understood, it will be easy for the scientists to replicate similar conditions in the lab and expand blood forming stem cells before transplantation into a patient. This will be of particular importance in bone marrow and umbilical cord blood transplantations and will be helpful in enhancing the safety and efficacy of these procedures.