Stem cells harvesting from bone marrow

Autologous hematopoietic stem cells are obtained (or harvested ) from bone marrow or peripheral blood. The technique for harvesting autologous hematopoietic cells depends on the anatomic source (i.e., bone marrow or peripheral blood). A surgical procedure is necessary for obtaining bone marrow. Multiple aspirations of marrow are obtained from the anterior and posterior iliac crests until a volume with a sufficient number of hematopoietic cells is collected (i.e., 600-1200 mL of bone marrow). The bone marrow then is processed to remove fat or marrow emboli and usually is infused intravenously into the patient like a blood transfusion. 

Two research teams have reported the results of promising experiments that suggest stem cells harvested from a patient s own bone marrow could one day be used to repair the damage caused by an acute myocardial infarction. The studies... 

Figure 1 Forward scatter (FSC) and right-hand scatter (RHS) from (a) peripheral blood stem cell, and (b) bone marrow harvests.

Bone marrow is the natural site of hematopoiesis and was therefore the first source of hematopoietic stem and progenitor cells. In addition to the hematopoietic cells primary stroma can also be collected simultaneously from this source. However, as the harvesting of cells from bone marrow is an invasive procedure that requires manual extraction under spinal or general anesthesia, alternative sources are preferred whenever possible, although, for allogeneic stem cell transplantation, bone marrow is still the source of choice [23]. 

The bone marrow is not the only source of hematopoietic stem cells. Such cells are present in low numbers in peripheral blood, and these can be expanded in number with specific factors. Peripheral blood stem cells have the major therapeutic advantage that their harvest is relatively painless and less invasive. Likewise, umbilical cord stem cells can also be obtained in a non-invasive manner from... 

The aim of a bone marrow transplant is to replace the abnormal bone marrow stem cells with healthy stem cells from a donor. Healthy stem cells are normally harvested using a syringe to withdraw bone marrow from the rear hip bone of the donor. They are then infused into the patient via a catheter in the chest area. Before the infusion, the patient receives chemotherapy or radiotherapy to destroy the diseased bone marrow stem cells so that the infused stem cells have a chance to grow free of complications from diseased cells. 

Stem cell therapy involves infusion of specialized cells utilized to perform specific functions. The traditional use of cell therapy includes harvest and cryopreservation of autologous hematopoietic cells either from the bone marrow (old approach) or mobilization and pheresis of hematopoietic stem cells from peripheral blood using stem cell-mobilizing cytokines such as hematopoietic colony-stimulating factors (G-CSF, GM-CSF) or chemokine inhibitors (AMD-3100). A more recent stem cell source is umbilical cord blood that has rich pleuripotent potential and can engraft at lower doses than bone marrow or mobilized peripheral blood stem cells. 

The primary advantage of MSC for utilization in cell therapy is the ease with which they can be harvested from the bone marrow, isolated by plastic adherence, expanded in culture, genetically engineered, differentiated, and handled in vitro. The ease with which mesenchymal stem cells can be iron-dextran labeled (Ittrich et ah, 2005 Arab et al, 2004) and monitored by MRl... 

In conclusion, we have shown that successful treatment of MI and I/R AKI with MSC holds substantial promise for the development of novel, MSC-based interventions that can improve the treatment of severe, and still largely therapy-resistant, clinical ischemic myocardial infarction as well as ARF that results from I/R injury. Pluripotent MSC, because of their versatility and the ease with which they can be harvested from the bone marrow, culture expanded, and engineered, appear to be a particularly well-suited stem cell type for these clinical indications. 

In addition to bone marrow and peripheral blood, hematopoietic stem cells are also found in umbihcal cord blood (UCB). UCB is an attractive source for several reasons. Because the stem cells are collected from placental blood, there is no risk to the mother or the baby. There is also very low risk of hansmissible infectious diseases such as cytomegalovhus and Epstein-Barr virus. In addition, the cells are available immediately because the donor does not have to be located and harvested. Initially, UCB was obtained from sibhngs but now recipients of transplants from unrelated donors accountfor almost all patients who receive UCB transplants. It is estimated that more than 2,000 unrelated UCB transplants have been performed worldwide. ... 

Early on, bone marrow stem cells were harvested from the posterior and anterior iliac crests or the sternum, while the patient or donor was under a general anaesthetic. It was fairly rapidly established that a minimum number of nucleated cells was necessary to ensure engraftment, and that this related to the body weight of the recipient. At this point, it was not possible to identify the stem cells or early precursor cells immuno-logically, and a total nucleated cell count of the harvested material was obtained, into which the body weight of the recipient was divided in an attempt to ensure an adequate harvest. Normally, approximately 1 litre of harvested blood and marrow would be required to ensure the presence of a sufficient number of stem cells for an adult patient. The harvesting procedure would last for 1-2 h, depending on ease of aspiration, and... 

Bone marrow was harvested from adult male mice and then transplanted into Isogeneic female recipient mice that had been treated with a level of irradiation sufficient to destroy their own hematopoetic stem cells (see the figure). Although the dose of irradiation given was lethal to mice that did not receive a transplant, the majority of the recipient mice receiving the transplant survived. After 4 weeks, peripheral blood from the recipient mice was analyzed. The composition of the blood was normal with respect to all blood cell types. Every blood cell examined was determined to be positive for the presence of the Y chromosome. 

Stem Cell Transplant. Stem cells can be found in either the bone marrow or the peripheral circulating blood. They also can be found in umbilical cord blood and fetal marrow and liver. Before stem cells can be harvested from a donor, mobilization of stem cells into the peripheral blood is stimulated by the use of cytokines. A process called apheresis is used to collect the stem cells from the donor s blood. These harvested stem cells are then injected into the patient. As with a bone marrow transplant, it is also possible to perform an autologous stem cell transplant. The transplanted patient will usually begin to produce new blood cells ten to twenty-one days after receiving the harvested stem cells. 

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