Bone marrow: location, role, diseases and donation

Bone marrow: location, role, diseases and donation

Bone marrow is a liquid organ essential for life that is found inside all of our bones. It is to be differentiated from the spinal cord located in the vertebral column, the role of which is to transmit information between the brain and the body. Bone marrow is made up of hematopoietic cells. Bone marrow dysfunctions can lead to serious blood diseases and require a healthy bone marrow transplant.

Definition: what is bone marrow?

The bone marrow is a spongy, soft, liquid substance. “It is a vital organ, like the heart, kidneys and lungsimmediately informs us Doctor Catherine Faucher, hematologist specializing in bone marrow and Director of Hematopoietic Stem Cell Collection and Transplantation at the Biomedicine Agency. Bone marrow has nothing to do with spinal cord. The spinal cord is a nerve cord inside the spine that distributes the body’s nerves.

Location: where is the bone marrow located?

The bone marrow is very widespread in the body. “We find it inside the majority of flat bones. The cells that compose it are the hematopoietic stem cells. They look like small cubicles, like the galleries created by bees. Hematopoietic stem cells live almost everywhere in the body on the surface of flat bones. They ensure the production of a vital element which is blood. Unlike other better-known organs, such as the heart, liver or kidneys, the bone marrow is a liquid organ that works continuously in order to constantly renew blood elements,” specifies the hematologist. In fact, the lifespan of blood cells is on average 4 weeks.

The bone marrow that produces the most blood cells in adulthood is located in the bones of the pelvis (hips), shoulders (scapula), spine (vertebrae), ribs, skull and sternum.

What is its role in the immune system?

The bone marrow makes all the blood cells or globules thanks to hematopoiesis. These cells are essential to help humans live: white blood cells (leukocytes), red blood cells (erythrocytes) and platelets (thrombocytes). THE bone marrow dysfunction can lead to the appearance of serious blood diseases.

Red blood cells for oxygenation

The role of red blood cells or erythrocytes is the transport of oxygen in the blood, in particular thanks to hemoglobin. Oxygen molecules are thus transported to the cells of the body. Besides, the blood holds its Red colorbecause the main cells that make up blood are red blood cells.

White blood cells for immunity

White blood cells play an important role in immunity, to protect the body from foreign substances. Two types of white blood cells are made by the bone marrow; these are the polymorphonuclear and related cells as well as the lymphocytes. Polymorphonuclear cells help fight bacterial infections. “In the case of an abscess filled with pus, for example, it is the polymorphonuclear cells that intervene.

The second type of white blood cells are lymphocytes (T lymphocytes and B lymphocytes), whose function is to produce antibodies. “They are synthesized during vaccination, for example, to provide lasting immunity. It is these leukocytes which also help fight against viruses”.

Platelets for hemostasis

THE pads are involved in blood clotting. Their role is to seal wounds or bleeding (hemorrhage) on the skin through hemostasis. Platelet cells clump together at the lesion to stop bleeding.

What diseases attack the bone marrow?

Bone marrow diseases can be grouped into two groups: malignant diseases blood and non-malignant diseases.

Malignant blood diseases or hematological malignancies, cancer of the bone marrow

The main bone marrow cancer is acute leukemia. “It is characterized by an unlimited proliferation of blast cells, which are immature and useless cells. Progressively, blast cells take the place of hematopoietic stem cells. They spread into the blood and prevent the bone marrow from functioning: it no longer produces blood cells..”

Leukemias can be acute or chronic. Malignant blood diseases also include myelodysplastic syndromes (MDS). These conditions target the immune system while lymphomas mainly affect the lymph nodes.

Non-malignant blood diseases

Although they are non-malignant, blood diseases are often serious. “One of the main diseases isMyelosuppression, in which the bone marrow stops working. The bone marrow is no longer capable of producing blood cells. The origins of this hematopoietic stem cell disorder are unknown; it could be an autoimmune disease. Bone marrow suppression is acquired or genetic.

Other non-malignant genetic blood diseases exist such as:

  • Thalassemias;
  • Sickle cell anemia;
  • Diseases of the immune system such as severe combined immunodeficiency (SCID) or bubble baby : the baby is born without immune system cells.

Bone marrow cancer: what are the symptoms?

“There are no characteristic symptoms of bone marrow cancer”informs us Dr. C. Faucher. “The symptoms of sickle cell disease and lymphoma have nothing to do with each other.”

Generally speaking, when the production of normal blood cells is reduced, or even very reduced, general signs may occur, but which are not signs of a serious blood disease :

  • Fragility to infections due to lack of white blood cells;
  • Shortness of breath caused by a deficiency in red blood cells;
  • Healing difficulties reveal a lack or dysfunction of platelets.

If a person does not feel well, an appointment with their doctor, who will order a blood test, is essential. insists the specialist.

Is bone marrow cancer treatable?

Cancers and non-malignant blood diseases are indications for bone marrow transplantation.

Bone marrow donation and collection

Who can donate bone marrow?

The most important selection criterion for registering as a bone marrow donor is compatibility with the patient. “THE human leukocyte antigens or human leukocyte antigens (HLA) are there immune system identity card of each person. These are biological markers coming to us half from the father and the other half from the mother. By looking for a compatible healthy donor, we ensure that the marrow transplant functions optimally, but we also try to cure cancer-like diseases in order to save the patient’s life.” explains Dr. Faucher.

“When a patient suffers from a serious blood disease, doctors first look for a compatible donor among those close to them, particularly among siblings (in children from the same two parents). We therefore have a one in four chance to find a donor”, reveals the specialty in hematology.

Three criteria are essential to register as a voluntary bone marrow donor:

  • Be aged 18 to 35 at the time of registration: bone marrow donation is possible up to 60 years old. Hematopoietic cell grafts from a young donor are richer and offer a greater chance of cure;
  • Be in excellent health;
  • Accept a blood or saliva sample: “From a blood or saliva sample, we determine the patient’s HLA group in order to establish their biological identity card. This way, we will know if one day the donor is compatible with a patient.”.

Becoming a “guardian of life”: a commitment that must be carefully considered

In Europe, all the logistics of donation and bone marrow transplantation are handled by the Biomedicine Agency, according to the bioethics law. Donation is a voluntary, voluntary, anonymous and free act.. The donor does not know the name of the recipient, and vice versa.

Also, once the person is registered in the national register of voluntary bone marrow donors, it may take a month, a year or 10 years before they are contacted. When registering, the person makes a time commitment. It is therefore essential to find the answers to the questions you ask yourself by taking the time to learn about bone marrow donation. The Biomedicine Agency website answers all questions in an educational manner. It also includes video testimonials from young donors who have already been collected.

Once the donor’s profile has been validated, a saliva collection kit is sent to their home and returned in a stamped envelope. After a few weeks, the donor receives a message to confirm their registration, in the form of a number (because the donation is anonymous). If one day the donor is contacted because he is compatible, he has a few weeks to prepare.

How is a bone marrow sample taken?

  • Blood sampling

There are two main techniques for bone marrow donation, as Dr. C. Faucher informs us. “In 80% of cases, it is a blood sample, such as when donating red blood cells. Four days before the donation, the donor takes a medicine to remove the cells from the blood. On the big day, the donor is lying down and…