Frequently Asked Questions 1. Stem Cells Q  What are stem cells? A  Stem cells are the body’s founder cells, the original building blocks of life for the developing embryo. They develop into the different types of cells needed to make up the human body (skin, blood, muscle, bones, nerves, glands etc).		FAQ      Stem Cells      Procedures      Blood & Other Tests      Pricing      Netcells Cryogenics      Our Laboratories      Other

Q  What classes of stem cells are there?

A  There are four classes of stem cells: totipotent, pluripotent, multipotent and unipotent:

• Totipotent
  Totipotent cells are considered the "master" cells of the body because they contain all the genetic information needed to create all the cells of the human body (including the placenta). A fertilized egg is a totipotent stem cell. After 3 - 4 divisions of totipotent cells, there follows a series of stages in which the cells become increasingly specialized.


• Pluripotent
  Pluripotent stem cells are descendants of the totipotent stem cells of the embryo. These cells, which develop about four days after fertilization, can differentiate into any cell type, except for totipotent stem cells and the cells of the placenta.


• Multipotent
  Multipotent stem cells are descendents of pluripotent stem cells and antecedents of specialized cells in particular tissues. For example, haematopoietic stem cells, which are found primarily in umbilical cord blood and bone marrow, give rise to all of the cells found in the blood, including red blood cells, white blood cells, and platelets. Another example is neural stem cells, which can differentiate into nerve cells and neural support cells. Multipotent cells are permanently committed to a specific function.


• Unipotent Cells
  Unipotent stem cells or Progenitor cells can produce only one cell type. For example, erythroid progenitor cells differentiate into only red blood cells.

Q  What types of stem cells are there?

A  Embryonic stem cells are derived from embryos which are typically 4-5 days old. These embryos are a hollow microscopic ball of cells called the blastocyst. Embryonic stem cells are pluripotent cells i.e.: they can differentiate into any cell type, except for totipotent stem cells and the cells of the placenta.

A  Embryonic stem cells are derived from embryos which are typically 4-5 days old. These embryos are a hollow microscopic ball of cells called the blastocyst. Embryonic stem cells are pluripotent cells i.e.: they can differentiate into any cell type, except for totipotent stem cells and the cells of the placenta. A. Adult stem cells, are undifferentiated cells found in small numbers in most adult tissues (including umbilical cord blood) and differentiate to yield the major specialized cell types of the tissue or organ. The primary roles of adult stem cells in the body are to maintain and repair the tissues in which they are found. They are obtained from:

• Umbilical cord blood
• Bone marrow
• Peripheral blood
• Adipose tissue
• Neural tissue
• Skin
• Liver

Q  What is the difference between embryonic stem cells, umbilical cord blood (UCB) stem cells, and bone marrow stem cells?

A  Embryonic stem cells are cells that are taken from an embryo typically 4-5 days old. They are the richest form of stem cell and can develop into every type of cell in the human body. They are however associated with many ethical, religious, and legal issues.

A  Stem cells from the umbilical cord are adult stem cells. They are a rich source of early stem cells particularly haematopoietic stem cells (blood forming stem cells), which are used to treat a host of blood related diseases. A. Bone marrow contains haematopoietic stem cells (blood-forming stem cells), which are adult stem cells. They mature into one of the three types of blood cells: white blood cells, which fight infection; red blood cells, which carry oxygen; and platelets, which help the blood to clot.

Q  What is so unique about umbilical cord blood stem cells, as opposed to bone marrow stem cells?

A  Studies suggest that stem cells from cord blood offer some important advantages over those retrieved from bone marrow:

• Stem cells from cord blood are much easier to get because they are readily obtained from the placenta at the time of delivery.



• A broader range of recipients may benefit from cord blood stem cells. These can be stored and transplanted back into the donor, to a family member or to an unrelated recipient. For a bone marrow transplant to succeed, there must be a nearly perfect match of certain tissue proteins between the donor and the recipient. When stem cells from cord blood are used, the donor cells appear more likely to “take” or engraft, even when there are partial tissue mismatches.



• A potentially fatal complication called graft versus host disease (GVHD), in which donor cells can attack the recipient’s tissues, appears to occur less frequently with cord blood than with bone marrow (even in a perfect tissue match). This may be because cord blood has an immature immune system and certain cells, usually active in an immune reaction, are not yet educated to attack the recipient.



• The use of cord blood may make blood stem cell transplants available more quickly for people who need them. About 30,000 individuals each year are diagnosed with conditions that could be treated with a bone marrow transplant. Approximately 25 percent of these individuals have a relative who is an appropriate tissue match. While suitable donors can be located through national bone marrow registries, the process can take months. There is a 1 in 40,000 chance of finding a perfect match and 30%-40% of individuals requiring a donor, never find one. Donors can be located within 4 months for about 50 percent of patients. It often is more difficult to find a bone marrow match for members of non-white ethnic groups; transplants from cord blood may make timely treatment available for more of these individuals. Banked stem cells from cord blood can be more readily available, and this can be especially crucial for patients with severe cases of leukemia, anemia or immune deficiency who would, otherwise, die before a match can be found.



• Cord blood also is less likely to contain certain infectious agents, like some viruses, that can pose a risk to transplant recipients.



• In addition, some studies suggest that cord blood may have a greater ability to generate new blood cells than bone marrow. Gram for gram, there are nearly 10 times as many blood-producing cells in cord blood. This fact suggests that a smaller number of cord blood cells are needed for a successful transplantation.



• Cord blood stem cells also offer some exciting possibilities for gene therapy for certain genetic diseases, especially those involving the immune system.

Q  What illnesses can stem cells treat?

A  Most of the body's specialized cells cannot be replaced by natural processes if they are seriously damaged or diseased. Stem cells can be used to generate healthy and functioning specialized cells, which can then replace diseased or dysfunctional cells. Replacing diseased cells with healthy cells, called cell therapy, is similar to the process of organ transplantation, except that the treatment consists of transplanting cells instead of organs. (www.isscr.org)

A  Umbilical cord blood is a rich source of haematopoietic stem cells and to date has been used to treat over 50 blood related disorders. The main use so far has been childhood leukaemia, lymphoma, thalassemia, sickle cell anemia and Fanconi’s anaemia, aplastic anaemia, immune deficiencies and some metabolic disorders.

A  However, significant research is being undertaken worldwide in stem cell therapies and there is much promise for a variety of diseases including bone repair, type1 diabetes, spinal cord injuries, corneal and retinal reconstruction, Parkinson’s disease, to name just a few. The use of stem cells for heart tissue regeneration (following heart attacks or in heart failure) holds particular promise for the near future.

Q  What is the characteristic that enables these cells to ‘cure’ a diseased blood system, as with leukaemia?

A  The leukaemic cells must first be completely destroyed by chemotherapy and in some cases radiotherapy. While this treatment kills the diseased cells, it also results in the healthy cells being destroyed, particularly dividing cells. Haematopoietic stem cells are continuously dividing cells, and are thus destroyed by the chemotherapy. The resulting lack of white blood cells reduces the patient’s ability to fight infection, and it is this that may result in the patient’s death. Umbilical cord stem cells given intravenously to the patient home in on the bone marrow and the stem cells then build a complete new blood and immune system.

Q  How likely is it that my child will ever need these cells?

A  Hopefully never. You need to view it as an insurance policy; you always hope that you never need it, but if you do it is available. The added benefit is the possibility of use for a sibling, should the need arise.

A  Studies in the US have been done to calculate the lifetime probability (age 0-70) that an individual will undergo a stem cell transplant. They reported that 1:435 people will receive their own stem cells for treatment; 1:400 persons will receive someone else’s stem cells; and the combined total number of stem cell transplants will be 1:217 persons. Reference: J.J. Nietfeld et al. Biology of Blood and Marrow Transplantation, March 2008

Q  What is HLA?

A  This stands for Human Leukocyte Antigen, and it defines tissue-types within the human body.

A  HLA determines the tissue match, which determines the likelihood of possible transplant compatibility between people.

Q  What is a tissue type?

A  It is a set of unique proteins (called antigens) found on the surface of the body’s cells, including the blood cells

A  An individual’s tissue-type is defined by the characteristics of six genes (A, B, C, DRB1, DQB1 and DPB1), collectively known as the human leukocyte antigen group (HLA). Testing for HLA groups, known as “tissue-typing”, is usually performed on a small blood sample and involves analyzing the genes that code for the HLA proteins.

Q  How many different tissue-types are there?

A  The total number of different tissue-types is not known. The HLA genes that define our tissue-type are very variable. Therefore it is extremely unlikely that two randomly selected individuals would have identical tissue-types.

Q  What is the possibility of matching within the family?

A  There is a one in four (1 : 4) chance that siblings will be 100% match. For it to be a 100% match, there needs to be a 6/6 HLA tissue-type match. For stem cells, we only require a 4/6 of the major HLA match, thus there is about a 45% chance that we can use the stem cells for a sibling. The chances of a match within a family go up exponentially and there is a one in eight (1 : 8) chance for parents and a one in sixteen (1 : 32) parents and grandparents.

Q  Is it possible to obtain stem cells later on in life?

A  Yes, typically stem cells have been sourced from bone marrow and peripheral blood and are retrieved at the time of need. However their quantity becomes less as we age and it is also likely that they may become diseased. Internationally, adults have started storing their stem cells, in case they need them later on in life.

A  Scientists are continuing to discover stem cells in other areas of the body (i.e. adipose tissue (fat), neural tissue etc).

Q  Are there enough stem cells in the cord blood for treatment?

A  The amount of cells required in transplantation is proportional to the weight of the patient, so the chance is better for a child than for an adult.

A  Currently research is being carried out worldwide to amplify (grow) stem cells, so that greater quantities are available in the case of transplantation. There has been limited success in this area, although this technique has not yet been perfected. It is hoped that this will become available in the near future.

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