Monday, January 24, 2005

Stem Cell Update: Bone Marrow

Here are some of the latest developments on the stem cell research front.

Bone marrow is doing a lot of work in actually curing diseases and ailments. Here and Here

For those of you who think all this stuff about the evils and failures of embryonic stem cell (ESC) research is fabricated by right-wing religious radicals, this article from Nature.com sounds the alarm concerning immune system problems related to ESC. Here are a couple of excerpts:

Most human embryonic stem-cell lines, including those available to federally funded researchers in the United States, may be useless for therapeutic applications. The body's immune defences would probably attack the cells, say US researchers. When embryonic stem cells are added to serum from human blood, antibodies stick to the cells. This suggests the cells are seen as foreign, and that transplanting them into the body would trigger the immune system to reject them. "We've found a serious problem," says Ajit Varki, a cell biologist at the University of California, San Diego.

The problem arises from contamination from the growth and creation process in the lab. There have been no such difficulties with adult stem cells and their cultures.

The hope of miracle cures brought about as a result of ESC research remains a glimmer in the eyes of those who have a lot of money to make if the Federal Government releases the ban on new ESC lines.

7 comments:

XBIP said...

Great info. I am going to pass it along.

Catez said...

Hi Phil,
Been a while since I read the journals on this. What I recall is that adult stem cells are only effective when used on the originator. e.g. Your adult stem cells are used for you. Otherwise there will be the same MHC problem. The finding reported in Nature is significant - as it was always thought that as well as being pluripotent the ESCs would not cause the MHC problem. Interesting post.

Phil Steiger said...

Catez-

Thanks for the thoughts. It is true, as fas as I have understood the issue, that most of the applicability of adult SC has been to the donor of the cells. But pluripotency is a possibility as a few researchers have pointed out. The President's Council on Bioethics website has a few transcripts and reports on that very issue.

Catez said...

Hi Phil,
Ok. But what I would want to see is published data and results. That's where the proof in the pudding lies. I'm not arguing for "harvesting" ESCs from aborted embryos - no way! It's not the adult SCs cannot have pluripotency - there's been interesting research on cellualr and extra-cellular stimuli in relation to that. The problem is MHC incompatibilty - which means they are only donor-effective. Pluripotency is restricted to the donor because of that. What is significant about the Nature report is that they are throwing up exactly the same concern for ESCs with regard to compatibility.

Phil Steiger said...

Catez-

Laying aside all the potential/non-potential for ASC pluripotency, I wonder how much of an issue that really is.

Pluripotency is a requirement for the usefulness of ESCs because the human donor is destroyed to harvest the cells. By definiton, the donor cannot use his or her own cells.

On the other hand, ASCs are taken from the donor to aid in their own recovery. Parents can elect to keep an umbilical chord for their child (and the mother apparently), bone marrow is used, placents are possible replacements for SCs, cells from women's arms are being use to cure incontinence...etc. The point being that the very use of ASCs does not require pluripotency. If someone needs SC therapy, they are their own doner.

Catez said...

Hi Phil,
I should let you know I'm a scientist (grin). I think you are confusing pluripotency and compatibility. Pluripotency is not about cross-matching donors. Pluripotency is the term to describe the ability of a stem cells to develop into any kind of cell - e.g. a muscle cell, a neuron, a neutrophil and so on. It means that cell has the potential to differentiate into any kind of cell.
Compatability is about whether the pluripotent cell can be used in some-one who is not the donor. The problem with adult stem cells is that they are already somewhat committed - a neuronal adult stem cell will develop into a neuron. It will also only be compatible with the donor.
An embryonic stem cell is not committed - it can develop into one of many different kind of cells (theoretically - there are extracellular factors involved). It is also not committed in terms of immune compatability - it can be used outside the donor.
Now - the significance of the Nature report is that they are presenting research indicating that ESCs do have some commitment to compatability - i.e. they cannot be transferred from one person to another.
This is very important. They are saying that while ESCs are pluripotent, they may also be incompatible. From the scientists perspective that is a large spanner in the works.
Adult stem cell research is the way to go. There is research being done here in NZ with neuronal adult stem cells and although very early days the results are proving interesting. The position of these scientists (doing the research here) is that adult stem cell research is the ethical and hopefully beneficial approach.
God bless.

Phil Steiger said...

Catez-

Thanks for the clarification!