What is a stem cell transplant?
Most stem cells are in your bone marrow. You also have some that circulate from your marrow into your blood. Bone marrow stem cells turn into red blood cells, white blood cells, or platelets to help your body stay healthy. If your bone marrow is damaged or destroyed, it can no longer make normal blood cells. In a stem cell transplant, healthy stem cells are placed in your body through an IV to help your bone marrow start to work right.
When the stem cells come from another person, it is called an allogeneic transplant. The donor may be a relative or a complete stranger. The important thing is that the donor's immune system markers are closely matched to yours. This is more likely when the donor is your brother or sister.
When the stem cells come from your own blood or bone marrow, it is called an autologous transplant.
There are three types of stem cells:
Multiple births may occur after the one cell zygote forms. In the case of mono-zygotic twins, like my own mother and her twin sister, both have exactly the same DNA. What started out as one becomes two. In the case of triplets, two are usually monozygotic or identical, while the third has a unique genetic heritage. It is rare for triplets to be completely monozygotic, but it does occur. Monozygotic twins or triplets are always of the same gender, either all boys or all girls. We could say more about other multiples, but I'll leave that up to your own research.
The zygote spends the next 5-7 days traveling down the Fallopian tube. As it travels it divides and reproduces into more and more cells. The resulting ball of cells is known as the blastocyst. This ball posses an inner cell mass that subsequently becomes the embryo. The embryo ultimately grows to become the fully developed child. The outer layer of cells or ortropho-blast forms the placenta, the membranes that nourish and protect the embryo. The blastocyst reaches the womb or uterus around day 5, and implants into the uterine wall on about day 6.
As I said, the problem lies with deciding whether the developing zygote is human and deserving of protection according to our Creator's command to honor and protect human life (Exodus 20:13; Deut.5:17). This decision also ties into the question of abortion and contraception. I discussed this in an earlier post in which I maintain that human life begins with conception:
- Umbilical cord blood stem cells multiply to form all the various components of human blood. For that reason they are called hematopoietic, that is, they create blood cells. They can be banked for later use. They can be transplanted to anyone else whose immune system markers match the donor's. They can also be used to treat hematological (blood related) diseases of the donor. They serve as an alternative to bone marrow transplantation when diseases such as non-Hodgkin's lymphoma and Hodgkin's lymphoma, leukemia, multiple myeloma, and aplastic anemia have damaged or destroyed it. Other uses for this type of stem cell are being studied, such as the treatment of immune system defects, diabetes, sickle cell disease, and thalassemia.
- Adult blood stem cells occur in many tissues and can differentiate into specialized cells in their tissue of origin and also trans-differentiate into specialized cells characteristic of other tissues. For example, hematopoietic stem cells can differentiate into all three blood cell types as well as into neural stem cells, cardiomyocytes (heart muscle), and liver cells.
Adult stem cells can be isolated through plasmapheresis, that is separating the plasma from the cells and transfusing them back into the blood stream. They are already being used to treat hematological (blood related) malignancies and to modify the side effects of cancer chemotherapy. Furthermore, autologous stem cells (your own cells) are being used in clinical trials in patients who have suffered myocardial infarction (heart attack). Their use in several other conditions has not been validated or is experimental at this time, despite some claims to the contrary.
- Embryonic stem cells are pluripotent. That means they can turn into many kinds of cells as the human embryo develops and grows. Researchers derive these cell lines from the inner cell mass of the 5 to 7-day-old blastocyst. This is the area of genetic science that causes the most problems, because of multiple disagreements about when human life develops. The question: is the blastocyst human even before it implants to the wall of the woman's uterus and thus deserving of protection?
Multiple births may occur after the one cell zygote forms. In the case of mono-zygotic twins, like my own mother and her twin sister, both have exactly the same DNA. What started out as one becomes two. In the case of triplets, two are usually monozygotic or identical, while the third has a unique genetic heritage. It is rare for triplets to be completely monozygotic, but it does occur. Monozygotic twins or triplets are always of the same gender, either all boys or all girls. We could say more about other multiples, but I'll leave that up to your own research.
The zygote spends the next 5-7 days traveling down the Fallopian tube. As it travels it divides and reproduces into more and more cells. The resulting ball of cells is known as the blastocyst. This ball posses an inner cell mass that subsequently becomes the embryo. The embryo ultimately grows to become the fully developed child. The outer layer of cells or ortropho-blast forms the placenta, the membranes that nourish and protect the embryo. The blastocyst reaches the womb or uterus around day 5, and implants into the uterine wall on about day 6.
As I said, the problem lies with deciding whether the developing zygote is human and deserving of protection according to our Creator's command to honor and protect human life (Exodus 20:13; Deut.5:17). This decision also ties into the question of abortion and contraception. I discussed this in an earlier post in which I maintain that human life begins with conception:
What we see in the Psalm 51 verse as well as others related to it (Matthew 1:18-20; Luke 1:30-44; Jeremiah 1:5, etc.) is the whole continuum of human beginnings. Like David, we begin with the heated act of sexual union as a man's sperm planted in a woman's body unites with her ovum. We are still uncovering the details of how this actually works out biologically. The sexual act and the actual birth are a continuum leading to a living, breathing human person secretly created by God in the depths of his or her mother's womb.
A complication in all of this is in-vitro fertilization, the development of embryos outside the uterus, in petri dishes. Are these developing embryos also human and worthy of protection even before they are inserted into the woman's uterus? And what about the storing of these embryos for later use? Many ethical and legal questions cluster about this issue.
I shall not attempt to work through all the questions in this post—there are many. What I do suggest is that we approach this whole issue with deep humility and reverence for the mystery of human life. God uses us as his co-workers in the awesome mystery of continuing creation, especially the creation of human life. At the same time, we know of the desire of many stem cell researchers to use their new knowledge to produce, save, protect and enrich life. They deserve our prayers and the most careful thinking we can offer to support them in their work.
We have much work to do and it must be done together.
I shall not attempt to work through all the questions in this post—there are many. What I do suggest is that we approach this whole issue with deep humility and reverence for the mystery of human life. God uses us as his co-workers in the awesome mystery of continuing creation, especially the creation of human life. At the same time, we know of the desire of many stem cell researchers to use their new knowledge to produce, save, protect and enrich life. They deserve our prayers and the most careful thinking we can offer to support them in their work.
We have much work to do and it must be done together.
