You may have read recently about an anti-abortion group secretly videotaping Planned Parenthood personnel as they discussed sale of fetal tissue (from abortions) to be used for research. I thought, whew, at least this doesn’t impact Parkinson’s research, now that adult stem cells can be used. So I was surprised to read in an excellent New York Times article on the event this paragraph: “Stem cells derived from adult tissue may eventually replace fetal ones, researchers say, but the science is not there yet.”
Yikes! What happened to adult stem cells? Didn’t someone win a Nobel Prize when they developed adult stem cells? Can’t we just leapfrog over all the controversies of fetal stem cells and use adult cells?
Whoa, let’s back up. What are stem cells and why are they important to Parkinson’s disease? Stem cells are the early “uber-cell” that can become many different types of cells: blood, marrow, skin, etc. Not surprisingly, the richest source of stem cells are from the embryo. Embryonic stem cells can generate all the major cell types of the body (they are “pluripotent”).
Stem cells have also been isolated from various other tissues, including bone marrow, muscle, heart, gut and even the brain. These “adult” stem cells help with maintenance and repair by becoming specialized cells types of the tissue or organ where they originate. BUT because adult stem cells become more committed to a particular tissue type during development, unlike embryonic stem cells, they appear to only develop into a limited number of cell types (they are “multipotent”).
However, there is a third kind of stem cell: the induced pluripotent stem (iPS) cells, discovered in 2007. And yes, there was a Nobel Prize for it in 2012: the Nobel Prize in Physiology or Medicine to John B. Gurdon of the University of Cambridge in England and Shinya Yamanaka of Kyoto University in Japan. IPS cells are created when scientists convert or “reprogram” a mature cell, such as a skin cell, into an embryonic-like state.
There are three ways (at least) that iPS cells could combat Parkinson’s:
–Disease Model: Get a basic understanding of how good neurons go bad and stop producing dopamine
–Drug Testing: Develop a “petri dish” of bad neurons to quickly evaluate new PD therapies
–Stem Cell Therapy: Use stem cells (maybe even your own!) to correct those bad neurons
Michael J. Fox Foundation has this to say about the promise of stem cells:
“…Considerable progress has been made in creating dopamine-producing cells from stem cells. The development of new cell models of Parkinson’s disease is a particularly promising area of stem cell research, as the current lack of progressive, predictive models of Parkinson’s disease remains a major barrier to drug development. Cell models of Parkinson’s disease generated from stem cells could help researchers screen drugs more efficiently than in currently available animal models…”
A European website, EuroStemCell , neatly summarizes the obstacles to stem cell therapy for PD:
“Stem cell therapies for Parkinson’s disease are not yet ready for use in patients. Much work still needs to be done before clinical trials can go ahead. For now, the main challenges for scientists are:
–To identify the type of cells that has the most potential for research and new treatments. So far, researchers have had most success making dopamine-producing neurons from embryonic stem cells, but it is not yet clear whether the lab-grown neurons are close enough to naturally produced nigral neurons to succeed as therapies.
–To find out how to grow neurons in sufficient quantities and at high enough safety standards to treat patients.
–To establish exactly how and where to transplant the cells so that they work properly in the brain without causing side effects.”
I’m still unclear whether fetal stem cells (vs Induced Pluripotent stem cells) are essential to PD therapies. But why artificially tie the scientists’ hands? With so many unanswered questions, it would seem wasteful to prevent scientists from using this type of stem cell, especially when the fetal tissue would otherwise be discarded, and the woman getting the abortion has given her informed consent.
For a poetic view of stem cells, check out the winner of EuroStemCell’s creative non-fiction contest.