Where are Stem Cells Found?
For human transplantation protocols, hematopoietic stem cells can be collected from a variety of sources including the marrow, blood, and umbilical cord blood obtained at the time of delivery.
Bone Marrow: The major place Where are Stem Cells Found
Marrow is the traditional source of hematopoietic stem cells for allogeneic and autologous transplantation. The marrow, Where are Stem Cells Found, is typically aspirated by repeated placement of large bore needles into the posterior iliac crest, generally 50 to 100 aspirations simultaneously on both sides, while under regional or general anesthesia. The lowest cell dose to ensure stable long-term engraftment has not been defined with certainty, and a typical collection standard contains more than 2 x 108 nucleated marrow cells/kg recipient body weight. Current guidelines indicate that a volume of up to 20 mL/kg donor body weight is considered safe.
Marrow harvesting is considered a very safe procedure and serious side effects are rare. A review of almost 10,000 unrelated healthy adult donors reported to the National Marrow Donor Program (NMDP) revealed that 70 percent of donors fully recovered by 2 weeks and the risk of serious complications were 1.2 percent; most of which were mechanical with nerve, bone, or tissue injury and resolved within 6 weeks.
As with adults, serious complications in donors younger than age 20 years were rare. The majority of marrow donors younger than age 2 years required allogeneic blood products after donation because of the large volume of marrow required for older, larger recipients. A survey of pediatric transplantation hematologists confirmed that 90 percent of centers were willing to perform a marrow harvest on children, even on those younger than 6 months old.