Monday, January 23, 2012

Background on Four Types of Stem Cell Research

This blog post contains general background information on four types of stem cell research.  I'm writing it because the term "stem cells" is used to describe several different lines of research, and it is important not to mix them up.  Good news from one type of "stem cell" research should never be used to suggest that a different type of "stem cell" research is going to be successful.

Quick Summary
Here is a very quick summary of four types of stem cell research:
1. "Burt"  Reboots the body's immune system to stop the autoimmune attack.  First, the patient is given very powerful drugs to shut down their immune system, then they are given drugs which causes the body to mobilize it's own adult stem cells to rebuild the immune system, without the autoimmune flaw.  Has resulted in the best cure results of any research to date, but is also the most dangerous.
2. "Zhao"  Patient's immune cells are removed and stem cells from the umbilical cord used to help retrain them   to stop the autoimmune attack.  The immune cells (without the stem cells) are then put back in the patient.  Good results and appears to be much safer than Burt.
3. Several companies (example: Viacycte) are attempting to grow new beta cells from stem cells.  They are taking undifferentiated stem cells and trying to find the recipe to cause those stem cells to differentiate into beta cells.  None of this work is in human trials right now.
4. Many stem cell clinics (example: Xcell) will infuse bone marrow stem cells in the hopes that this will cause the patient to regrow beta cells and improve their type-1 diabetes.  Although many clinics will provide this service, I have never seen a peer reviewed study showing that it improves type-1 diabetes.

How They Are Different

Burt's research does not use external stem cells.   Rather, the patient is given a drug which "mobilizes" their own internal stem cells.  People have several different forms of adult stem cells in their body.  Part of Burt's protocol is to give the patient a drug which is well known to cause them to generate more of their own bone marrow stem cells, and cause these cells to be released into the blood stream.

Zhao's research is very different from the rest, because he is not trying to grow beta cells from the stem cells.  Instead, he is using them to train the immune cells not to attack beta cells.  (This is sometimes called "curing autoimmunity".)

You may ask, "why should stem cells cure autoimmunity?"  It's a very good question, and I don't know the answer.  But I'm not an immunologist, and for me it is far more important that a treatment work, than that I understand how it works.  Many treatments are used for years before we understand exactly why they work.  (Aspirin is a 100+ year old example.)

Beta Cells from Stem Cells
There are several companies working on ways to differentiate beta cells from stem cells.  Generally, they differ from each other two ways.  First, in the kinds of stem cells they start with (embryonic from an embryo, embryonic from cord blood, or different types of adult cells or adult stem cells that have been treated in some way to make them undifferentiated).  Second, in the recipe they use to transform these undifferentiated stem cells into beta cells.

Stem Cell Clinics
These guys harvest bone marrow stem cells from a person, and then put them back into that person or a different person.  They differ in exactly how they put the stem cells back in (in the blood or directly in the organ that needs them), and also in what processing or separation is done to the bone marrow cells before being put back.

My opinion of the stem cell clinics is very low.  They are a cash up front business without evidence that they help anyone.  For example, to approve a new drug, the US FDA requires four clinical studies to show that it works and is safe.  Currently, there is not one stem cell clinic, that has published even one peer reviewed study (that I have found), that shows that it works.

Most of these clinics are in third world countries, but there was one, called Xcell in Germany.  Years ago, Xcell said that they were running two studies to show that their treatment would help type-1 and type-2 diabetics, respectively.  Neither of these studies were ever published in a peer reviewed journal, and last year the German government shut down Xcell after an 18 month old baby died of complications from a stem cell treatment at the clinic.  (And this after a 10 year old boy almost died after the same procedure!)

I often see these clinics cite Burt's work as peer-reviewed, scientific research that suggests their clinics are on the right track. But this work is wildly different from the work done at these clinics and the success of one does not support the treatment of the other.  As an example: Burt uses three drugs in his trial.  These clinics sometimes use one of those drugs, and sometimes none at all.  They never use all three of them, and never get close to the same procedures that Burt uses.  My guess is that you will see these guys citing Zhao's work soon as well, even though Zhao is using a totally different type of stem cells and not even putting in the patient.

Other Terms to Understand

Adult vs. Embryonic
These are the two types of stem cells that we have heard about for the longest, and the loudest.  Much of the arguments about stem cells (especially in the US) are phrased in terms of Adult vs. Embryonic.  However, I have come to believe that, while this difference is critical religiously, politically, and socially, that it is not important in terms of research aimed at curing type-1 diabetes.

The confusion comes from the fact that in the early days of stem cell research, embryonic stem cells were the only undifferentiated stem cells known.  So when people talked about the power of embryonic stem cells, they were often talking about the power of undifferentiated cells.  However, now we can get several different types of undifferentiated stem cells from adult sources, and from different embryonic sources.

Differentiated vs. Undifferentiated
A better way to talk about stem cells, is undifferentiated (and if so, what is their source) vs. differentiated (and if so, how were they differentiated). Differentiated stem cells are those which have already specialized into a specific type of cell. For example, a beta cell. Undifferentiated stem cells have the potential to do this, but have not yet done it. With the current research results, it appears that undifferentiated are not useful for growing beta cells in the simple minded way used by the current clinics. However, both Burt and Zhao have had success using them in other ways, and undifferentiated stem cells have not yet been tested (in people) as a source for growing beta cells.
A lot of the recent news in stem cell research is reporting on different ways to create different types of undifferentiated adult stem cells.  These different type stem cells might have different properties and be good or bad at different things, but we really don't know yet.

Another type of research news that we have gotten recently, but is not as common, is success in turning different types of undifferentiated stem cells into beta cells.  It is especially important to turn them into beta cells that generate insulin when presented with sugars.  The has been some success at this, but none of it has progressed into human trials (that I know of) as yet.  Even if they did, we would still need to either encapsulate them or cure the autoimmunity before they would be a cure for type-1.

Self vs. Others
Any kind of stem cells can be gotten from the person being treated (self) or from someone else (others).  This is true for both embryonic stem cells, and adult stem cells.   You can get embryonic stem cells (for example, from the cord blood) and use them on the person you got them from.  Or you can get adult stem cells from that same person.   Self stem cells are going to have fewer immune issues than those from others.

Joshua Levy
All the views expressed here are those of Joshua Levy, and nothing here is official JDRF or JDCA news, views, policies or opinions. My blog contains a more complete non-conflict of interest statement.
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1 comment:

Phillip Humphries said...

My fiance has been struggling with this since birth, my heart breaks every time she goes to the hospital and she tells me "I'm so tired of this...I wish god would just take me." There isn't anything in this world I wouldn't do for this cure. I don't want to lose her and I don't want her to suffer anymore. If god gave us these cells, then we must use them. I have been watching the progress of this cure and I pray for that day to finally come when Brittany Bedwell doesn't have to suffer anymore and can live a normal happy life. Most people don't know but with type 1 diabetes you are very pron to infections...Infections that stay in your body, no matter how well she takes care of her self, no matter how she watches what she eats, how she takes her meds, we go to the hospital at least twice a month because she has gone into DKA. This being caused by infected kidneys, antibiotics have pretty much done all they can do. Doctors say that she needs to be under the care of a specialist at all times...Yet we can't afford it and she has been denied SSA and SSD more then once...We are trying again and this time hope she gets it so that we can keep her under the care of a doctor. However, like I said, there isn't anything I wouldn't do for this cure...I love her and losing her would kill me inside. Thank you for your blog and I will be sure to keep reading it.