Biologists have been studying regeneration for hundreds of years, but only now has an indication surfaced that higher forms of life may have the potential to regrow damaged organs, limbs or tissue.
When the day comes that a human heart can regrow sections destroyed in a heart attack, or when a spinal cord break is repaired, or an amputated limb grows back, some of the thanks may be due researchers working at the Eccles Institute of Human Genetics, University of Utah.
Announcing a possible step toward a science of regeneration last week were Shannon Odelberg of the Eccles Institute; Dr. Mark Keating, formerly of the Howard Hughes Medical Institute on the U. campus and now at Harvard; and Angela Kollhoff, with the Howard Hughes Medical Institute as well as the Huntsman Cancer Institute.
Their amazing study was published in the scientific journal Cell and reported in Friday's Deseret News.
Odelberg and Keating discovered a way to trick highly specialized muscle cells into reverting to a primal state, called stem cells. Stem cells are the generalized precursor cells from which specialized cells form.
The team began working on the project in 1997. Their first experiment that showed promise was performed at the end of 1998.
"Of course, you're excited," said Odelberg, describing his reaction when the muscle cells divided into something that looked like stem cells. "But you also realize you have to reproduce this."
After the success, the team worked diligently to confirm the finding. In repeated experiments, they determined that about 9 percent of the muscle structures they treated split to produce either smaller cells that looked like muscle cells or other dividing and multiplying cells that looked like stem cells.
Then, using established techniques for manipulating stem cells, they tried to see if they make them change into different types of specialized cells. The stem cells began to respecialize into cells that looked like bone, cartilage and fat.
The first experiments into animal regeneration were carried out by the Italian scientist Lazzaro Spallanzani in the 1760s. Spallanzani is most famous for proving that maggots do not spontaneously generate from spoiled food, but he also made important discoveries in many other areas of biology.
He found that snails and amphibians were able to regenerate parts of their bodies. For example, if a newt loses a leg, it will grow back. The regeneration happens because newt muscle, bone, blood and other cells are somehow plastic, as if they were stem cells.
But Spallanzani observed that this amazing ability did not extend to higher animals.
In mammals, highly specialized cells like muscle "are not thought to ever divide and multiply like this," Odelberg said. That is, not until now.
"Several researchers within the last century have looked at regeneration in various animals, and a lot of studies on a cellular level were conducted at the turn of the century." But only in the last 20 to 25 years have scientists begun to understand the factors that control the process.
In their research, Keating, Odelberg and Kollhoff treated mouse muscle cells with a chemical preparation that forced a gene called msx1 to switch on. Under the right conditions, with the proper growth factor and serum, the gene made the cells change.
The normally immutable muscle cells became plastic, reverting to a precursor state.
"I think this is part of a growing research field, in which researchers are starting to show that mammalian cells . . . may be a little bit more plastic," Odelberg said.
He believes that these studies will show that even highly specialized cells will be able to transform. The possibility could open up a host of new therapies, from repairing heart attacks to restoring brain material lost to Parkinson's disease.
"It might be possible in the future to even regenerate complex body parts, like limbs in mammals," he said.
"This research could take us in several different directions."
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