Adult vs. embryonic stem cell success now quoted at 70 to 0
The group that brought you the 65 successes number we used to see all the time in stories about adult vs. embryonic stem cells has now increased their success number to 70. As you may remember from earlier blogs, almost all of the stem cell successes are with cancers, where infusing patients with bone marrow stem cells after they have submitted to intense chemotherapy does seem to improve the health of some of them.
Embyronic stem cells, on the other hand, have yet to prove themselves. While this is not surprising considering the limitations on this form of stem cell research, many use the "failure" factor to discredit embryonic stem cell research.
Meanwhile, yet another "first human trial" has been announced for embryonic stem cells. Today's New Scientist news service (online at newscientist.com), in the article First embryonic stem cell trial on the cards, by Andy Coghlan, states:
The first treatment derived from embryonic stem cells might soon undergo clinical trials. The cells would be used to help repair damaged spinal tissue. . . . the plan is to treat people that have acute spinal injuries with oligodendrocyte progenitor cells grown from human ESCs. Oligodendrocyte cells support neurons in the brain and spine by sheathing them in myelin, a fat that helps neurons to transmit signals.
Spinal "crush" injuries often cause a loss of myelin, and so destroy the capacity of nerves to transmit signals. Previous experiments carried out by in rats with damaged motor nerves suggested that oligodendrocyte progenitor cells injected into the spine can redress this, helping to restore movement.
The company now says it has evidence from cell-culture experiments that the treatment will not cause harmful immune reactions.
Here are some immediate concerns:
- No mention was made in the article that application to conduct such a study has been made to the FDA. Other groups have already had studies approved and started. The company mentioned in this article hopes to have the process ready for testing in humans "a year from now".
- The company only did the immune reactions studies in vitro (not in animals), and it has yet to release details of the research.
- The finding doesn't affect other potential stem cell treatments, because the brain and spinal cord give only mild or no immune response to challenge. As the article author says, "Compared with other tissues, these organs have a relatively inactive immune system." Others note that evidence on immunogenicity of these cells is quite variable.
Marie Godfrey, PhD