Mexico already has a public umbilical cord blood bank that represents life expectancy for many patients, particularly children.
Hunter syndrome is a rare disease caused by the lack of an enzyme that regulates basic cellular functions and without which sugar accumulates in cells, damaging them irreversibly. Without treatment, this disease causes mental retardation, stunted growth and heart problems that lead to death in children who suffer from it before reaching the age of 10. Until recently, only bone marrow stem cells from a donor could help a child with Hunter syndrome produce the enzyme. But unless the donor’s marrow cells are very similar to the patient’s, the transplant produces severe complications. Fortunately, there is already an alternative: using umbilical cord blood stem cells. In May of last year, the magazine New England Journal of Medicine reported that of 20 children affected with Hunter syndrome and who were transplanted with this type of cells, 17 survived and are now attending school.
Mothers of all cells
The first cells produced by the egg fertilized by the sperm have the potential to form a complete human being, hence their name: stem or mother cells. totipotential. As they reproduce and separate from their original location (the blastocyst), they lose the ability to generate a complete human being, but retain the ability to generate any type of cell; they are then called pluripotential. We also have a small reserve of cells in the organs and tissues, capable of renewing or repairing them: they are even more differentiated (specialized) cells than the stem cells, known as multipotential. This is the case of blood stem cells that are found deep inside the bones, in the bone marrow. These cells retain the ability to produce all the cells that make up blood such as erythrocytes (red blood cells), leukocytes (white blood cells) or platelets – although this limitation has recently been questioned, since it has been possible to develop them other types of fabrics. An abundant amount of these cells circulates in the blood of newborns and many remain in the blood of the umbilical cord and placenta. Umbilical cord blood cell transplantation constitutes an invaluable opportunity for those patients, mainly children, who suffer from various blood and genetic diseases, including various types of leukemia and other conditions such as Fanconi anemia and the aforementioned Hunter syndrome. .
Among blood cells there is not only hemoglobin, the protein that transports oxygen to all organs so they can breathe, but also leukocytes or white blood cells, whose macrophages, lymphocytes and neutrophils are basic weapons of our body’s defense system that we know as immune system. In this defense army, soldiers identify each other with a kind of uniform (or at least part of it), since they carry recognition proteins on their surface that we call antigens, or more properly HL A (for the English acronym for Antigens). Human Leukocytes) and that in fact are also on the surface of any nucleated cell in the body (not all our cells have a nucleus; red blood cells or erythrocytes are an example of non-nucleated cells).
If the immune system does not recognize the HLA uniform or antigen of any cell as its own, it destroys it. For a marrow transplant there are six HLA antigens that are of utmost importance, since those of the donor and the patient must be the same. In a cord blood transplant, doctors can use blood whose cells contain only three HLAs similar to the patient’s. This is due to the immaturity of the umbilical cord cells, since the immune system in the newborn is not yet fully developed, so rejection is less likely, since the cord cells would not recognize the cells of the umbilical cord. adult.
Life banks
At the end of the 1980s, it was found that only 30% of patients with some type of hematological (blood) cancer could have a compatible family member who would donate bone marrow for a transplant. This fact prompted the investigation of alternative methods. Dr. Gluckman, in Paris, was the first to perform an umbilical cord stem cell transplant on Matthew, a six-year-old boy who suffered from Fanconi anemia. The cord belonged to his newborn brother. Matthew is now in college and is considered the first patient to have a successful cord transplant. From then on, Umbilical Cord Blood Banks (BSCU) began to be created to have an inventory of units always available for transplant. In our country we already have a BSCU, from the National Blood Transfusion Center, dependent on the Ministry of Health, a public project started in Mexico in 2003.
Modern biotechnological techniques allow that after the birth of a baby, it is possible to isolate stem cells from the umbilical cord and placenta, that is, separate them from other cells; concentrate them by putting them in a smaller volume; analyze them to make sure they are alive, there are enough of them, and there are no contaminants; classify them to know who can use them according to their structure, and preserve them at very low temperatures in a bank.
The quality control applied to blood is vital. A mistake can cost the life of the child who requires it tomorrow. That is why a BSCU applies the strictest measures to ensure that the blood is free of viruses (such as those that cause AIDS and hepatitis) and other pathogens, many of them coming from the mother or the result of poor collection. But the key factors, in the case of blood, are whether there is sufficient volume of stem cells in it, because in addition to being scarce, due to their physiological similarity they can be easily confused with other white cells or leukocytes (stem cells are the most immature cells that will give rise to the leukocytes that we know and that circulate in the blood). For this reason, it is necessary to do a fine count taking as reference a protein called CD34+, which only stem cells contain on the surface and which is therefore considered a marker, that is, a way to distinguish them from others. With an immunological technique, which consists of using another protein (antibody) that binds to the marker (CD34+) of the cell, it is possible to count the number of stem cells present in the blood of an umbilical cord. There must be at least 80 milliliters of blood and 8 x 108 white blood cells (there is an always constant proportion between white blood cells and stem cells). This dose from a single umbilical cord can be used to treat a person weighing no more than 50 kilograms.
For adults there is the possibility, and it has already been applied successfully in Europe and the USA, of using blood from two umbilical cords, obviously from two different donors, but compatible with the patient. Even in Japan, in recent months, transplants have been performed in adults, from a single cord, with excellent results.
Blood diseases that can be treated by cord stem cell transplantation:
Leukemia: A disease consisting of a massive accumulation of leukocytes (white blood cells) in the blood. Its main clinical manifestation is a decrease in red blood cells, granulocytes and platelets in the blood.
aplastic anemia: A blood disorder that occurs when the bone marrow cannot make enough white blood cells, red blood cells, or platelets. It can be mild or severe and its origin is hereditary or acquired.
Hereditary aplastic anemia is caused by a chromosomal abnormality, such as Fanconi anemia or Dyskeratosis disease. Acquired aplastic anemia can be caused by constant contact with toxic chemicals such as pesticides, by radiation emitted in radiotherapy processes or by the use or consumption of drugs, among other causes. However, almost half of the reported cases do not have an identified cause or origin.
Wiskott-Aldrich syndrome: An X-linked inherited disorder, characterized by the development of eczema, bleeding, and increased susceptibility to infections.
Lasbeta-thalassemias: A common disease in the Mediterranean area and in which, due to genetic mutations, the synthesis of beta-globins, the protein component of hemoglobin, is reduced.
Neuroblastomas: Cancerous tumors that generally originate in the adrenal gland tissues of the abdomen, but also in the nervous tissue of the neck, chest, abdomen or pelvis, but which tend to migrate (metastasize) to the bone marrow. Neuroblastoma is a tumor that appears predominantly in early childhood.
In many research laboratories (for example, the Cord Bank of Barcelona, Spain) the reproduction of stem cells is already carried out in a reactor to increase their number (cell expansion), before transplanting into the adult patient. In Mexico, at the Oncology Hospital of the Siglo XXI National Medical Center, Dr. Héctor Mayani also studies the process of expansion and differentiation of blood stem cells. This suggests that, in the near future, umbilical cord blood units could be the necessary raw material for cellular differentiation, not only to produce blood cells, but even specialized cells from other systems, such as the nervous, cardiovascular, the renal, etc., which would turn the BSCU into true cell factories.
As you will notice, it is urgent to grow the financial capacity of these public banks, increasing their reserves. That is, you need to have several thousand cords to increase the probability of giving a positive response to whoever approaches you in search of umbilical cord blood compatible with yours.
Donate a navel
To obtain the umbilical cords, the BSCU of the National Blood Transfusion Center has the support of students from the Biological Pharmaceutical Chemist career of the Faculty of Chemistry of the , who carry out their social service in three different hospitals of the Ministry of Health. Health. These young people approach future mothers to inform them about the possibility of becoming donors. There are three requirements: to be in perfect health, to be over 18 years of age, and to sign the informed consent, which implies ceding all rights over the use of blood to the bank. This allows the gynecologist, once the baby is born, and if there is no risk to the health of the mother or the newborn, to hygienically remove the blood that remains…