What Are Stem Cells?
Stem Cells refer to those progenitor cells that are characterized by the ability to renew themselves and have the potential to differentiate into one or more types of cells.
Differences between protocols with stem cells from bone marrow and from umbilical cord blood from stem cells from fat tissue. First, it is helpful to understand differences of the stem cells from each source.
Potential and quantity:
Bone marrow has a natural concentration of hematopoietic stem cells. These cells create blood that is transferred to the blood stream of the body, and can be combined with a mixture of growth factors to create millions of pluripotent progenitor cells. The quantity of stem cells extracted from the bone marrow is defined by volume when the doctor performs the extraction. Because the bone marrow regenerates constantly, it is possible to perform periodical extractions according to the requirements of the procedure without causing side effects to the patient.
Umbilical cord blood is rich with hematopoietic stem cells, because at time of birth these stem cells are “traveling” from the liver (where the blood is produced for the fetus) towards the bone marrow (where the blood is produced after the birth). This mixture contains tens of millions of multipotent progenitor cells. The quantity of cord blood collected is limited to the residual volume of blood in the umbilical cord at the time of birth and is not possible to extract additional same cord blood afterwards.
Access to bone marrow requires a small access to the inside of the bone. This procedure is invasive and local anesthesia is used during the extraction. The extraction could be performed at any time on any person as long as normal operation procedures and sterility cautions are performed. Use of bone marrow has some limitations for allogeneic procedures (see paragraph on compatibility) when a compatible donor is necessary.
Collecting umbilical cord blood is not an invasive procedure, because it is taken immediately after the baby is born and before the placenta gets removed. The extraction can only be performed at the time of the childbirth and should be done following normal hygienic practices to avoid contamination of the cord blood.
In both cases compatibility works similarly. When the donor and the recipient are the same person (autologous), compatibility is a complete match. If the donor and the recipient are different (allogeneic), HLA compatibility tests must be performed before any procedure. The HLA test identifies 6 markers; some bone marrow treatments are possible only with compatibility of 6 out of 6, or 5 out of 6 matched markers; while umbilical cord blood has more flexibility, allowing procedures with 4 of 6 matched markers. Use of any allogeneic procedures is limited by the necessity of finding a compatible donor.
Manipulation and storage
A collection procedure must be performed for any source of stem cells. The more complicated the procedure, the higher the probability of contamination of the stem cells or of collecting a reduced amount. Bone marrow is not processed to extract the stem cells needed for storage or transport, preventing reduction of the amount of stem cells. Umbilical cord blood generally goes through a separation process of its components and also through a process of cryopreservation. Some volume of stem cells will be lost due to the nature of the processes required to collect, separate and cryogenically preserve the cells. The cells can be stored in this way for a very long time.
ProgenCell performs only autologous protocols, performing the infusion immediately after extraction and activation of stem cells. These protocols do not require the separation of blood into components, nor storage, transport or cryopreservation, eliminating the possibility of contamination and decrement in the cellular quantity and viability introduced by these steps. ProgenCell uses total bone marrow for the infusion, infusing not only stem cells but also the growth factors and all components of the bone marrow.
Umbilical cord blood stem cells began to be used in 1988 as alternative to bone marrow. Today it is commonly used for treatments related to the hematologic system of the human body, in nonhereditary diseases. Worldwide more than 70 diseases can be treated with stem cells, and these treatments have been performed mainly on children due to the relationship between the weight of the patient and the amount of stem cells required for treatment. They are an excellent alternative in cases where there is no compatible family member and the search for a compatible person is difficult or counter-productive. Extracting bone marrow from a baby would typically be contraindicated. Storing the umbilical cord blood when the baby is born is recommended since it is relatively easy harvesting and store, and can be made readily available. Storage in private banks gives the family the advantage of having it available at any time, with guaranteed compatibility of these miraculous cells for the child, and a strong likelihood of compatibility for another family member.
Bone marrow has been used in procedures since the 1950´s in hundreds of thousands of cases to date. It is commonly used for the treatment of hematological malignancies, congenital immunodeficiencies and others. It does not make sense economically to have bone marrow banks because of the cost required to harvest and store the cells, in addition to the invasive procedure through which the donor must undergo. That is why the extraction only takes place when a patient requires the cells and a compatible donor is located. Some societies have enormous lists of donors with known HLA markers, facilitating the search of a compatible donor for the patient.
Conclusion: Experience with bone marrow is greater than with umbilical cord blood. Because of the flexibility of multiple extractions of bone marrow it is a “limitless” source of stem cells. For autologous use, the availability and compatibility are not obstacles. Because ProgenCell performs extraction of bone marrow and immediate infusion, this eliminates the need for handling, storage and transport.
IMPORTANT: If you are considering a procedure with stem cells from any source, it is important to take the following considerations:
Know the source, the donor. When an allogeneic procedure is performed, there is a high risk of tissue rejection causing Graft-Versus-Host-Disease (GVHD). The HLA compatibility of the donor is very important, as well as having comprehensive blood tests to screen for infectious diseases (CMV, Hepatitis C, etc) and a complete clinical history record to avoid donors with predispositions to hereditary diseases.
Supplier. In order to avoid complications in a procedure, the product is important; therefore it must a standard of quality such as Good Manufacturing Procedures. Otherwise the cells could be unusable if they were not handled carefully under these high standards during the separation process, packaging, cryopreservation, transport, thawing, etc.
Amount. Tissue regeneration requires a minimum amount of stem cells to be able to repair damaged tissues. The amount needed is tied to the weight of the patient and other medical factors. A single cord-blood unit may not have enough stem cells to treat an adult. There has been some success with technology being developed to cultivate these cells ex vivo, growing the number available.