Medical science continues to advance in many promising directions, tackling conditions, disorders, and medical concerns that were once considered impossible to treat. Vaccines have, over the decades, helped to contain and minimize infectious epidemics. New experiments in engineering are improving the way prosthetic limbs can bring more mobility to people.
And in cellular research, stem cell transplants are one of the most exciting new developments, and there’s great hope that this technique could be a way to address many conditions that, in the past, were considered untreatable, or difficult to handle, such as Autism Spectrum Disorder, or ASD. But what is a stem cell transplant? What makes it so special that it can go where other medical treatments can’t and possibly yield better results?
The Power Of A Stem Cell
A stem cell is unique in human biology because it is a “blank slate.” Ordinary cells in the human body, like hair, or skin cells, can only reproduce additional copies of themselves. When a person is cut, skin cells create even more skin cells to repair the damage. Other cells, such as heart cells, never reproduce at all, meaning any cellular damage that occurs to the heart is permanent.
Stem cells, however, are the building blocks of a human being. DNA may be the blueprint with a complete plan for a heart, lungs, brain and all other parts of the body, but stem cells are used to create those organs. The stem cell can program itself to become any cell required, from common, easily reproducible skin cells to more difficult nerve or heart cells. In other words, stem cells can help damaged cells repair themselves faster, or even replace cells that biologically, are irreplaceable.
As the name suggests, a stem cell transplant takes a unique part of human biology known as a stem cell and puts it in another location. As with any other transplant, such as organ transplants, or blood transfusion, this requires a high level of biological “compatibility.” The human body is naturally resistant to foreign substances, viewing them as possible threats like viruses, bacteria or other potential diseases. When the human body deems a foreign body a threat, it rejects it and attempts to remove it from the body.
This is why compatibility is so critical for transplants. If a body rejects blood that has been transfused due to incompatibility, a patient will get sick. If a body rejects a kidney that has been transplanted, a patient may die. In the case of a kidney transplant, the patient may die. So when it comes to a substance that can potentially replace new cells in the body, it’s not unusual that a high degree of biological compatibility is required. In the best-case scenario, there is a very close genetic relationship between the recipient and the stem cells being transplanted. This often means the stem cells come from the patient, or a close genetic relative, such as identical twins or any other sibling.
The stem cells that can become virtually any other cell in the body are known as pluripotent stem cells, and the human body does not naturally produce these except under specific circumstances, such as pregnancy. This is why, normally, the only way to gather biologically compatible pluripotent stem cells is by harvesting “cord blood” after the delivery of a baby.
“Cord blood” is the generic term for the fluids left in the umbilical cord after a baby is born. Because the umbilical cord acts as a conduit, delivering both nutrients to a growing baby, and carrying away waste materials, a large concentration of pluripotent stem cells is left here after birth.
The human body naturally produces other stem cells, but they are not pluripotent. Multipotent stem cells, for example, are cells that can convert themselves to any related cell. This type of multipotent stem cell is located in the bone marrow, which is the “factory” for blood used by the circulatory system. Bone marrow stem cells can become red cells, white cells and platelets, the primary cells found in the blood.
The Transplant Method
A stem cell transplant does not have to be as invasive as major transplants for organs. In some cases, a stem cell transplant is even less invasive than a typical blood transfusion. In the best-case scenario, a stem cell transplant takes the stem cell supply, either from cord blood, or another donor, and injects it intravenously into the veins. For some treatments, such as ASD, the injection may be intrathecal, rather than intravenous, which means an injection into the spine area.
If no cord blood or other donor is available, or sufficient, another step may be taken to harvest stem cells from bone marrow from the patient. In this scenario, some surgery is required for the medical team to access bone marrow in another part of the body and extract the stem cells. This is one of the most common methods used for treating leukemia, but science continues to research more ways to culture larger amounts of stem cells in the lab.