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Three Giant Steps for Stem Cells-breakthrough studies to treat diabetes, Alzheimer’s and spinal cord injuries
The controversial field of stem cell research got boosts from several directions this week, with three breakthrough studies published and a company announcing another new development.
By Kristen Philipkoski Wired.com
All of the work puts stem cell researchers one step closer to using the cells to treat people with diabetes, Alzheimer’s disease, spinal cord injuries and various other problems that are caused by irreparably damaged cells.
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The research is opposed by people who believe that life begins at conception because stem cells are extracted from human embryos, which are destroyed in the process.
In August 2000, President Bush limited stem cell research to cells that had already been taken from 64 embryos; that number was bumped up to 72 stem cell "lines" (called that because they can replicate indefinitely) a year later.
Genes give stem cells magic: For the first time, Princeton University researchers have identified specific genes that give stem cells their unique ability to develop into any of the 200,000 cells in the human body.
The researchers identified 283 genes common to many important types of stem cells, in research published in the Sept. 12 issue of Science.
In another study, published in the Sept. 11 issue of the Proceedings of the National Academies of Science, the same researchers identified about 4,000 genes that are active in the surrounding tissues that nurture stem cells and give them cues about how to behave. The researchers have published databases of the genes online and are free for anyone to access.
Stem cells take their cues from within as well as from surrounding cells, they said, and by looking at both, researchers will be better able to coax the cells into becoming heart, lung, brain or other types of cells.
"That is why we think these papers are so complementary," said Ihor Lemischka, an author on the Science paper, in a statement. "They form the Princeton group’s philosophy for how to proceed in stem cell biology. You have to do it simultaneously from the point of view of the stem cell and point of view of the micro-environment in which the stem cell resides."
The unbearable stemness of being: In other research also published in Science, scientists came up with more questions than answers about the genes that are common to stem cells.
They found that many of the same genes are found in all kinds of stem cells (from embryos or from adult blood, bone marrow or brains) — but a large number of them have not been sequenced and their function has not been determined.
"These genes may regulate their stem cell properties, what we call ‘stemness,’" said Miguel Ramalho-Santos, a molecular and cellular biology researcher at Harvard University. "The identity of these genes raises very interesting hypotheses as to how the behavior of stem cells is regulated at the genetic level."
They also found that embryonic stem cells and adult brain stem cells activate many of the same genes.
"This similarity is encouraging for efforts aimed at using embryonic stem cells to generate neurons for neurodegenerative disorders," Ramalho-Santos said.
A brand new brain: ReNeuron Holdings, Europe’s first listed stem cell company, says it has solved a sticky problem in its stem cell technology and expects to begin human trials in 2004.
That’s already three years later than they’d originally hoped. They’d hoped to treat patients with Parkinson’s disease and stroke by injecting fetal stem cells into patients’ brains, but found that the stem cells became genetically unstable after being replicated many times.
The company has licensed rights to a patent from Australia’s Amrad Corp, which ReNeuron says solves the instability problem.
"We’ve been struggling for the last year and a half with this stability problem, but I’m optimistic that we are going to crack it now," said Martin Edwards, CEO of ReNeuron.
The company is in England, which is taking the lead in stem cell research thanks to the world’s most relaxed laws on the research. A stem cell bank funded by the government’s Medical Research Council should be completed in a year.
A guinea pig’s guinea pig: Johns Hopkins scientists have made a pacemaker out of a guinea pig.
The researchers say it’s the first pacemaker made of biological materials. They used gene therapy to convert part of the guinea pigs’ heart muscle cells into "pacing" cells.
"We now can envision a day when it will be possible to recreate an individual’s pacemaker cells or develop hybrid pacemakers — part electronic and part biologic," said Dr. Eduardo Marbán, a professor at the Hopkins Institute of Molecular Cardiology.
He said it will be several years before the pacemaker is used in the clinic.
Guinea pig heart cells spontaneously and rhythmically "fired" after the scientists genetically altered the level of potassium in the tissue.
The biological pacemaker could be a good option for patients who can’t have electronic pacemakers implanted because of the risk of infection, or for patients who are too small to accommodate one.
"This is akin to turning a clunky old car into a hot rod — if you have the parts and expertise, it can be done," Marbán said.
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