Dr. Young sent this response. Thank you Dr. Young.
Very primitive stem cells exist in a very low oxygen environment in our bodies. In fact some of our most primitive stem cells that we have discovered can survive well past seven days without an outside oxygen source. So, unless the stem cells they are referring to are actually progenitor cells, i.e., one-step removed from differentiated cells, I doubt if lack of oxygen is their immediate problem.
Most of the stem cells that are being transplanted these days come from other individuals, i.e., cord blood stem cells, etc., and are not matched for HLA markers. My suspicion is that the transplanted stem cells are being attacked by the person's own immune system as being non-self and gotten rid of in that fashion. Only the very primitive stem cells (referred to above) have a mechanism that can elude the host's immune system. And these are probably the few stem cells that actually survive the transplant.
Dr. Young
Know your model system and Tissue never lies - P.M. Johnston
Knowledge without an imagination is worthless - Albert Einstein
Adult stem cells do it better - H.E. Young
