|07-31-2001, 11:43 AM||#1|
Join Date: Jul 2001
Location: Saskatoon, Sask. Canada
Non invasive procedure
Dr. Young, with all these trials happening around the globe, when could we expect to see a non invasive procedure using our own cells so immunosuppressive drugs would not be needed.
Is there a proper delivery system already made that could sucessfully transplant cultured cells ?
I would imagine the best procedure would be an injection of cells to remylinate and stimulate regeneration.
I'm still a bit confused about this scar business. You have said in the past, the scar formation will not pose a problem, where many other papers say that the scar is a barrier which still has to be dealt with ?
I also wonder about the use of cells taken from CSF ?
Do you know of research using cells derive from CSF, and has there been sucess ?
I would like to hear the opinion of you other people as well.
|07-31-2001, 01:18 PM||#2|
Join Date: Jul 2001
Location: New Brunswick, NJ, USA
There have now been four studies in animals suggesting that stem cells can be injected systemically (i.e. intravascularly or intraperitoneally) and the cells somehow end up in the brain or spinal cord, at the injury site, and produced cells that look like neurons. Of the top of my head, these are the studies from Eva Mezey at NIH, Brazelton, et al at Stanford, and Chopp in Detroit. Chopp actually did it with a spinal cord injury model. So, it seems to work at least in animals.
In Russia, they seem to be injecting the stem cells intrathecally into people. From Dimitriy's explanation of the procedure that he underwent about two months ago, he had an injection (which I assume was a lumbar puncture from the fact that he had a headache afterwards) of human fetal stem cells (he provided me with a protocol that was apparently developed with or derived from Evan Snyder's approach to isolating stem cells).
Since the cells were obtained from a fetus, they were obviously a heterograft, i.e. from one individual to another, and therefore there is a risk of immune rejection due to immune incompatability of the cells. Note that Curt Fried and his group have transplanted human fetal neurons into over 100 patients with Parkinson's disease and they found that these neurons (as opposed to other cells) are not rejected by the host immune system after transplantation. So, there is a possibility that fetal neurons will not display antigens that promote immune rejection. I am not sure that this is the case.
In any case, what several of the Russian groups are apparently doing is to test people for the presence of auto-antibodies against CNS antigens such as neuron-specific enolase and glial fibrillary acidic proteins. This was the test that Dimitriy went through but I do not know what level response they considered acceptable and I have not heard of them rejecting any patient on the basis of their antibody testing. Apparently, also, Samuel Rabinovich at Novasibirsk may have been giving the patients pre-surgery immune suppression with cyclosporin. All these details are not clear and also I don't know how the Russian groups determine whether the cells have survived and are not immune-rejected after transplantation.
Let me address the issue of cells in the CSF and scarring separately.