Dummy’s Guide to Understanding Stem Cell Transplants

Stem cell research has appeared on the front pages once again. This week, the US Supreme Court announced that they have rejected an appeal that had been filed to block the government’s funding of stem cell research so that the research can proceed. The court refused to hear an appeal from scientists who have been challenging the federal funding for stem cell research — which is used with the hope that the cells will enable scientists to find cures for spinal cord injuries and Parkinson’s disease — on the grounds that it was violating a law that prohibits taxpayer financing for work that harms embryos.

Legal matters aside, the term is bandied about frequently and has become a sensitive issue to religious groups and the scientific community and, somewhere in between, many have no real concept of what exactly is a stem cell transplant. What better opportunity to provide a straight-forward explanation? So, toward that goal, following is a’dummy’s guide’ to understanding stem cell transplants.

What is a stem cell?

A stem cell is a special kind of cell that has the unique capacity to develop into the specialized cells that make up the tissues and organs of the body, such as heart cells, nerve cells and even inner ear hair cells.

How do they work?

Stem cells have a unique gift. They get attracted to the place of injury. They can be injected anywhere in the body and they will travel to the place of injury. Once they reach the place of injury, they can transform themselves into specialized cells to fix the injured part.

Modern history of stem cells

What I have found is very interesting and very surprising.

Stem cell research originated and started in ‘Institute for problems in Cryobiology and Cryomedicine’ in Kharkiv (Ukraine). During the Cold War, this institute conducted research on preserving human bodies (of Soviet leaders of course) so that they could be brought back to life 500-1000 years later once cure were found for the medical problems to which they succumbed. A simple  search of the web will reveal that there are still facilities in this part of the world that offer to preserve the body after death.

After the Chernobyl disaster the focus shifted to tissue re-engineering and human DNA. This is when the institute started experimenting with stem cells.

Sources of stem cells

There are three practical sources of stem cells:

  1.  Aborted fetus: This is the most contentious source
  2. Umbilical cord: It is possible to save the umbilical cord at the time of birth. Umbilical cord can be an excellent source of own stem cells.
  3. Autologous stem cells: Extract stem cells from one’s own body (for example, from bone marrow in the hips) and harvest them to increase quantity.

Best source of stem cells

It differs from person to person. Here are some of the considerations:

(a)  It is very common for stem cell transplant to be done for brain related injury. The only way for stem cells to reach the damaged brain area is by injecting them into blood. However, the place of injection matters. We have something called blood-brain barrier that guards our brain from any foreign object. It is after crossing this barrier that stem cells get into the spinal fluid and on their way to reach the damaged part of the brain.

Fetal stem cells are delivered before blood-brain barrier via intra-venous injection so that this barrier stops problematic stem cells (if any). Obvious problem with this treatment is it is very hard for stem cells to cross this barrier and reach the brain. The advantage is that a patient can be given huge amount of stem cells.

On the other hand a patient’s own stem cells can be given directly by-passing the barrier i.e. they can be injected directly into the spinal fluid. Since the cells are being injected in spinal fluid they have more chances of reaching the damaged part. However there is a disadvantage, there is a limit on quantity that one can inject directly in spinal fluid.

(b)  You should also consider the nature of injury. If the person was born with the problem then there is a good chance that autologous stem cells may suffer from the same issue and the stem cell transplant will not show any results.

(c)  Stem cells may degenerate if stored over a long time. This problem might affect stem cells from umbilical cord.

(d)  The single biggest problem with stem cell from discarded fetus is that you do not know what you are getting. If the stem cells from fetus have any issues then you are injecting these issues into human body.

When is one expected to see the results?

This is the most painful part. There is absolutely no guarantee that stem cells will work. There have not been many cases where stem cells have completely cured the problem. In the case of brain injury with younger children, there is no way of knowing whether stem cells have worked even if the patient shows improvement.

Ahhh…the wonders of science!