Advantage of Stem Cell Research

What is the advantage of stem cell research? There is a need for new cells in medicine to replace cells that are damaged. For example, in a heart attack, the heart muscle is damaged, and it is usually permanent damage. How are you going to replace that tissue? In the brain, Parkinson’s disease and others result from a lack of functional cells. Diabetes, specially type 1, the pancreas is damaged. Let’s get new cells to replace these! The problem is where we’re going to get them. Well, you could do a heart transplant, or other organ transplant. Organ transplants are hard to get. There are many more people waiting for kidney transplant than we have kidneys available. So, here is obvious the advantage of stem cell research.

The second problem is that the immune system ultimately will reject the transplant. A person who gets an organ transplant must take immune-suppressor drugs to keep the organ as long as possible.

What about using stem cells? Stem cell transplants are already performed every day. Bone marrow gets damaged when cancer is treated with radiation therapy and chemotherapy. All the cells, including the stem cells inside the bone marrow, are damaged. A person who is treated with radiation and chemotherapy for cancer is going to be severely anemic and immune-compromised; because their immune system would not be working (white blood cells would not be produced in sufficient numbers).

The strategy is the following: if the patient’s bone marrow is removed before therapy and stored literally in a refrigerator, “reinserted” after therapy, it has enough stem cells to form the new blood cells. These stem cells are called pluripotent. They are not totipotent (like the ones found in an embryo). They can give rise to all of the blood cells, but not others.

What about a patient who has blood cancer. The patient’s bone marrow can’t be used. You need a genetically matched donor to give his stem cells. You’ve probably seen advertisements in your community for becoming a member of a bone marrow registry. It is not a hard test and it is a wonderful thing. Imagine it; you could save a life with a very simple procedure of donating some stem cells.

Stem Cells From Your Own Fat

As a plastic surgeon in Los Angeles, Dr. Marc Hedrick’s practice included liposuction, where unwanted fat is removed from the body. Instead of throwing it away, he asked if there was something useful in it. When he looked at the fat under the microscope, he saw not just fat cells, but some other cell types as well, including what appeared to be bone and cartilage. Hedrick proposed that these specialized cells (bone and cartilage) got there because fat tissue must have some stem cells.

Hedrick knew about stem cells in bone marrow from his medical training. These are the stem cells that constantly replenish the population of red and white blood cells. When he took them and implanted them in animals, they would specialize into the tissue where they are located. In contrast, if you take a specialized cell and put it into another environment, it stays the way it was.

So, stem cells from fat can be put into damaged blood vessels and specialize into blood vessel cells, thus repairing the damage. Fat stem cells are reaching the clinic. The advantage of using fat stem cells is that a person’s own fat can be used to get them. They won’t be rejected by the immune system.

Hedrick and his colleagues have invented a way to get fat stem cells in about an hour in the operating room, while the patient is there waiting for the implant of stem cells. He needs about a pound of fat. That’s enough to get 200 million stem cells. This is enough for therapy. Recently some women in Japan received fat stem cells to help repair breast tissue after surgery for breast cancer. In Germany, a child got his own fat stem cells to help repair his skull after damage in an accident.

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What are Stem Cells

What are stem cells? Stem cells are unspecialized cells in the body that constantly divide to form a pool of cells that can then specialize when they are needed. When we have the union of the sperm and the egg to produce one cell, this in turn divides into a form called morula. The morula contains identical cells all of which are totipotent. This means that any single cell in the morula can divide and become virtually any cell in the human body, including embryonic tissue and placenta. The big change comes when it divides.

In the blastocyst, the cells become more specialized, but they still retain some potential to differentiate into almost any of the cells of the body, except some specialized ones like the placenta.

What we’re interested in is in what happens from here on. With each division, cells can differentiate from its parents and specialize more and more. They loose a little bit of their power to become anything. They go from pluripotent to multipotent. Multipotent cells are specialized cells which nonetheless have the ability to become a variety of cells. The multipotent hematopoietic cell, for example, which is the cell that forms blood elements, can become very varied elements in the blood.

These multipotent cells have the ability of maintaining an undifferentiated state.

Look at the picture. If a stem cell undergoes mitosis, it divides and produces two daughter cells. One of the daughter cells is exactly like the original stem cell. This one maintains the pool of stem cells from which to get new cells all throughout our lives. The other cell goes on to differentiate, going different pathways to become anything except a placenta or other early embryonic tissues.

When a cell goes all the way through a pathway, it can’t go back. This means that it cannot divide again and become less differentiated.

The ultimate stem cells are embryonic stem cells. They are totipotent. They can become any cell in the organism. At about the tenth day stage after fertilization there are several dozens of these undifferentiated totipotent cells in a human embryo. These cells can be removed from the embryo, grown in a laboratory dish and reproduced. In 1998, James Thomson at the University of Wisconsin showed that this is possible to do. Put them in a laboratory dish and they would grow indefinitely as a laboratory culture.

In laboratory experiments on animals, these embryonic stem cells can be induced to form many different cell types. In animals, these cell types coming from embryonic stem cells have cured brain damage, heart damage, muscle damage, etc. This has generated great excitement for their potential in human medicine.

The proposal is to use laboratory grown stem cells as a supply. You don’t need a lot of embryos to do this. The problem is that if I get some stem cells from someone else, they’re not mine. Those cells going into my heart would do the work, but then my immune system would ultimately reject them.

This has led to the proposal of therapeutic cloning. This is the subject of another article.

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