The bone marrow is
the inner part, the core, of the bones, where the various types of blood cells
are manufactured. Bone
Marrow Transplantation
By Manuel Luciano da Silva, M.
D
The original article was written in
Portuguese, translation done by Zsolt Orban, M. D.
This treatment won the Nobel Prize of Medicine in 1990. This technique has saved many human lives. People in general do not understand the mechanism of the bone marrow transplant. Here is an article that explains, in a very simple and clear form, all the functions of the bone marrow and the reasons why it is used in the treatment of certain cancers and leukemia's.
The bone marrow is
the inner part, the core, of the bones, where the various types of blood cells
are manufactured.
What is the bone marrow? It is the soft and fatty interior of the bones. It is the very core of the bones. It is the spongy, reddish part of the bones, which give such delicious taste to the Portuguese soup when beef or pork bones are used in making the broth…
What is the purpose of the bone marrow and what is its function? The bone marrows of the various bones in our body - of the sternum, ribs, vertebrae, bones of the pelvis and of the long bones -- are the FACTORIES where the various blood cells are produced!
In our bone marrows three principal types of cells are manufactured: (1) red blood cells or erythrocytes with the main function of carrying oxygen to every part of our body; (2) white cells or leucocytes with the purpose of defending ourselves against various diseases; and (3) platelets helping in the coagulation of the blood preventing hemorrhages.
What is the function of the blood? Besides carrying the oxygen and the food to every part of our body and of defending ourselves against diseases and preventing hemorrhages, it also helps our body to get rid of the waste products of our metabolism
We all know that blood means life. When we donate blood to another person we are giving that person renew life. Each person possesses an average a gallon of five litters of blood. Blood has two components: (1) plasma, the liquid part, 55% of its volume, consisting of water and few hundreds of different chemicals, proteins, minerals and sugars. And (2) blood cells, constituting the solid part, 45% of the total volume.
Transfusions
It was in 1900 that the physician researcher Karl Landsteiner, an Austrian American, discovered the existence of four different types of blood: A, B, AB and O (universal donor). For this sensational discovery he received the Nobel Prize in Medicine. Up to his discovery all transfusions were incomparable or impossible. In 1940 Landsteiner and Wiener discovered another blood type, or Rh factor: Rh negative and Rh positive.
Everyone knows the purpose and the effects of a blood transfusion. When a person is anemic, due to excessive blood loss, or because of a disease that causes anemia, a transfusion or transfusions can be given, of the same type of blood, so that the patient can be cured and many times this treatment saves his or hers life. Today hospitals all over the world use "rivers of blood" in dramatic treatments, saving many thousands of lives.
Since the beginning of the XX century blood has been used in millions of transfusions. But it is only in the last decade that medicine has been using bone marrow transplants on the treatment of various cancerous diseases. Why? Because it is in the bone marrow that all blood cells are manufactured.
It was in 1990 that Professor E. Donnall Thomas of the University of Washington was awarded the Nobel Prize, because he was the first to use with positive results bone marrow transplants in the treatment of leukemia's, lymphomas and other malignant cancerous diseases.
Automobile Factories
How does the bone marrow manufacture the various types of blood cells? We have heard many times that the highways are the arteries of our country. If the highways are the arteries used for the various types of cars to circulate, the various types of blood cells likewise circulate in our true arteries.
What are the materials necessary to built an automobile? Iron, cupper, various chemicals, and plastic substances. The same materials are needed in the manufacturing of the blood cells: iron, cupper, protein or plastic products and various chemical products.
Let us continue further with our analogy. From the car factories in Detroit or Chicago are rolled out trucks, automobiles and motorcycles. Similarly our bone marrow produces also: (1) red blood cells which we compare to trucks; (2) white blood cells - equal to all different types of cars, (3) and platelets which are the motorcycles.
Red blood cells or
erythrocytes, look like reddish donuts
White blood cells:
neutrophil and monocyte
White blood cells:
lymphocyte, eosinophil and basophil
We already know that the red blood cells - (trucks) - carry the oxygen to every cell of our body. The platelets - (motorcycles)- are necessary for coagulation to stop hemorrhage. And the white blood cells - (the different types of automobiles) - are absolutely needed to defend us from infections, allergies, parasites and different types of cancer!
The Mother-Cell of the bone marrow or Myeloblast or Stem Cell, gives origin to sixteen different types of cells which circulate in our blood.
Here are the general morphological types of the 16 different blood cells derived from the Stem Cell or Myeloblast. For the sake of our discussion we are only considering the white blood cells.
It is in the group of different white blood cells -- in the group of automobiles - that the secret of the treatment of malignant cancers resides -- with the treatment of bone marrow transplantation.
The Bee Queen
If we enter inside of the bone marrow -- the factories of blood cells-- the assembly line can be similar to a beehive. We see the bee queen -- the mother-cell of the bone marrow or myeloblast -- originating all the different types of our blood cells. This mother-cell produces platelets, red blood cells and white blood cells. Let us analyze the five different white blood cells:
(1) Neutrophils (which we compare to Chevrolets) specialize in the defense of acute infections. Pus is composed by this type of white cells, which have died as heroes in the front line as soldiers in a war defending our body.
(2) Eosinophils (or Fords) defend us against allergies and parasites.
(3) Monocytes (Buicks) act against chronic infections.
(4) Basophils (Dodges) are against certain virus and fungus.
(5) Lymphocytes (Cadillac's ). These are the most important. They work against cancerous cells.
What is the mechanism by which bone marrow transplant can help us in the cure of malignant diseases such as leukemias, lymphoma, aplastic anemia ( a condition in which the bone marrow stops producing red blood cells), multiple myeloma, breast cancer and childhood neuroblastoma?
Leukemia's
What is leukemia? Leukemia as its Greek name indicates is "cancer of the white blood cells". (Leukos = white plus hemia = blood). All five types of white cells spoken earlier can give rise to a leukemia if a specific cell starts multiplying in number out of a control causing leukemias of lymphocytes, leukemia of neutrophils, etc.
What happens when a leukemia appears? The bone marrow utilizes all the available raw material such as iron, proteins, and other substances, to produce only one type of cell, instead of producing all the types that are necessary for good health.
Let us now explain the types of treatments available for different types of cancer:
(1) surgery, (2) radiotherapy and (3) Chemotherapy.
Radiotherapy and chemotherapy work by eliminating cancer cells that are immature, and extremely sensitive to these treatments. The cells that are more mature even though they are older, are more resistant and do not die as a result of exposure to these treatments. This is the reason why these treatments for leukemias and lymphomas work.
But if the above described treatments do not give positive results, then we have to recur to the bone marrow transplantation treatment, which means we have to substitute the entire bone marrow of the sick patient. As you can imagine this is big enterprise!
Types of Transplantations
There are two types of bone marrow transplantations that can restore the normal production of blood cell factory - bone marrow- both in children and in adults.
(1) Autologous - the bone marrow transplant is coming from the same patient. How? After the patient is treated with chemotherapy, and the cancerous cells have ALL been killed, a treatment sample of bone marrow is extracted from the same patient which is then reinjected as if it were a self transfusion. The results will be good if ALL leukemic cells, cancerous cells, were rendered dead by the chemotherapy. The bone marrow -- about 200 cubic centimeters -- once injected in the vein of the patient, the stem cells or mother-cells of the given marrow go, by the circulation, to the bone marrow of the patient and there start producing normal blood cells, as if it were a new automobile factory.
(2)Halogenic - the bone marrow comes from a different person or donor. In order to accomplish this kind of transplantation the donor not only needs to have he same main blood type, but he or she has to match other characteristic of the patient's immune system. The receiver and the giver have to have the same genetic mosaic, so that the bone transplantation will not be rejected. All the "small stones" of the mosaic of the giver, have to match the "small stones" of the receiver.
It has been demonstrated scientifically that each group of people, such as the Portuguese, have a genetic and immunology composition, sui generis, or unique. This is the reason why the Portuguese Americans should have bone marrow bank in the United States.
In the United States all Oncology Centers are connected by computers and they maintain a national data base information with the immune characteristics of all possible bone marrow donors. We do no know when one of us or any member of our family will strike the need of a bone marrow transplantation and will need to use the services of these bone marrow banks. If giving blood is giving life, donating bone marrow is saving human life from certain death.
Now, the final question: How much blood is needed to do all the tests necessary to make a person a potential bone marrow donor? The Answer: ONLY 3 TABLE SPOONS OF BLOOD!
The Umbilical cord
In March 1996, as an experimental approach to the transplantations, blood from the umbilical cords started being used as material for bone marrow transplants. Why? Because the umbilical blood is very rich in myeloblasts, or mother cells, similar to the mother cells that exist in the normal bone marrow. In the United States there are already umbilical banks. We hope this approach of treatment will be successful because there is an abundance of umbilical cords and will be much easier to find a matching donor.