Stem Cell Research

[lucaspa]

If ES cells haven't helped anyone and always form a tumor, then why is it even an issue?

Because the ES cell researchers want to continue doing research with ES cells!

If you look carefully at statements on ES cells, you see the emphasis on potential, not accomplishments. What's more, in order to get around the ethical issues, ES cell researchers claimed early on (in the absence of data) that only ES cells could differentiate into all the tissues of the body. They hold to that dogma in the face of much data that some adult stem cells seem to have the same differentiation potential as ES cells. In trying to get an ethical justification, ES cell researchers have clouded the scientific issues.

 

[lucaspa]

I haven't read into the actual literature, but there certainly seem to have been a few successes due to ES. I'm a bit dubious of this claim that they ALWAYS go wrong.

ES cells always form a tumor when implanted in a mass. They do not form a tumor when injected in a suspension. The hypothesis is that ES cells produce autocrine/paracrine factors that stimulate differentiation. These factors need close proximity to other ES cells to reach high enough concentrations to trigger differentiation. So, the approaches with ES cells have been two:

1. Inject ES cells in a suspension. This has been tried in animals to treat animal models of Parkinson's, spinal cord injury, and cardiac repair, for example.
2. Get the ES cells to differentiate in vitro (a culture dish) and then implant the differentiated cells. This was tried many years ago in selecting cardiac cells from differentiated ES cells and injecting them into an animal model of cardiac repair.

The problem with #2 is that, when the ES cells differentiate in culture, only a small percentage of the cells form any given tissue. ALL the tissues form in any given dish. Much research with ES cells now is to try to direct the differentiation to one tissue. However, they are trying to do this based on small molecules changing the chromatin or other structure of the DNA to induce specific differentiation.

IMO, this misses a great oppportunity. The ES cells must be producing proteins that act on neighboring cells to cause them to differentiate down a particular pathway. So, withdraw the inhibition to differentiation in the culture media (ES cells must be prevented from differentiating, in contrast to adult stem cells who must be stimulated to differentiate) and then take the conditioned media and purify the proteins in it. Then test the individual proteins on new cultures of ES cells to identify those proteins that specifically direct differentiation. Then clone the proteins. The proteins could either be used by themselves (a la BMP to induce bone) or stimulate large quantities of ES cells to differentiate in vitro and then implant the differentiated cells.

Of course, this doesn't get around the rejection problem. How do you get an adult's ES cells? Either by cloning or by inducing adult cells to become ES cells (iPCs). The problem with iPCs is that, so far, it involves transduction of genes and some of the genes are oncogenes. So there are safety concerns.

 

[variant]

Because the ES cell researchers want to continue doing research with ES cells!

If you look carefully at statements on ES cells, you see the emphasis on potential, not accomplishments. What's more, in order to get around the ethical issues, ES cell researchers claimed early on (in the absence of data) that only ES cells could differentiate into all the tissues of the body. They hold to that dogma in the face of much data that some adult stem cells seem to have the same differentiation potential as ES cells. In trying to get an ethical justification, ES cell researchers have clouded the scientific issues.

Research always starts with potential, that is why we do research.

You are claiming in the absence of evidence that the potential is invalid.

The only way to ascertain potential is to do the research.

 

[lucaspa]

Research always starts with potential, that is why we do research.

You are claiming in the absence of evidence that the potential is invalid.

The only way to ascertain potential is to do the research.

That's not what I am claiming. So listen carefully. Yes, research starts with potential. However, if, after many, many tries, you can't get the "potential", then it's time to rethink whether there is really potential there. IOW, at some point you have to go from "potential" to actuality. You have to produce results from the research. This the ES cell field has not done.

The ES field is so poor at producing regeneration in animal models that my lab has more publications on regeneration using our adult stem cells than the entire field of ES cells!

Thomson published his paper isolating human ES cells in 1998. However, mouse ES cells were first isolated in 1981. So researchers have had 29 years to demonstrate the utility of ES cells for regeneration in animal models. What have they got? Maybe six or seven examples. All of which are isolated instances with no follow up in larger animals or human trials.

In contrast, mesenchymal stem cells were isolated from rats about the same time. There are hundreds of papers demonstrating regeneration with various adult stem cells in different animal models. I have 7. In humans, adult stem cells have passed phase II clinical trials for treatment of heart attacks to regenerate the cardiac muscle lost. Adult stem cells are in dozens of other clinical trials.

How many clinical trials are ES cells in? Nada. Zilch. Zip.

If you were reading the posts, there are real issues -- documented by research -- to the use of ES cells for regeneration of tissues. These issues contradict the "promise" the ES cells have.

 

[variant]

That's not what I am claiming. So listen carefully. Yes, research starts with potential. However, if, after many, many tries, you can't get the "potential", then it's time to rethink whether there is really potential there. IOW, at some point you have to go from "potential" to actuality. You have to produce results from the research. This the ES cell field has not done.

The ES field is so poor at producing regeneration in animal models that my lab has more publications on regeneration using our adult stem cells than the entire field of ES cells!

Thomson published his paper isolating human ES cells in 1998. However, mouse ES cells were first isolated in 1981. So researchers have had 29 years to demonstrate the utility of ES cells for regeneration in animal models. What have they got? Maybe six or seven examples. All of which are isolated instances with no follow up in larger animals or human trials.

In contrast, mesenchymal stem cells were isolated from rats about the same time. There are hundreds of papers demonstrating regeneration with various adult stem cells in different animal models. I have 7. In humans, adult stem cells have passed phase II clinical trials for treatment of heart attacks to regenerate the cardiac muscle lost. Adult stem cells are in dozens of other clinical trials.

How many clinical trials are ES cells in? Nada. Zilch. Zip.

If you were reading the posts, there are real issues -- documented by research -- to the use of ES cells for regeneration of tissues. These issues contradict the "promise" the ES cells have.

And none of this means a single thing when it comes to whether or not the government should fund ES research.

The ONLY reason that ES studies have had their funding held up by governmental sources is because of political complaints.

ES MAY be something and it may not be, the only way to determine this is to fully and completely research them. If you are claiming this has been done to it's fullest extent you are being intellectually dishonest.