Vitamin C Helps Stem Cells Become Heart Cells
Experts warn application to humans a long way off
MONDAY, March 31, 2003 (HealthDayNews) -- A chemical treatment can transform stem cells into cardiac cells that someday might be used to help failing hearts, researchers report, and the chemical that does this remarkable transformation is nothing but plain old vitamin C.
Researchers at Harvard Medical School exposed mouse embryonic stem cells to 880 bioactive substances, says a report in the online version of Circulation, and the only one that made the cells light up to indicate the transformation was vitamin C.
"Light up" is no figure of speech, says study author Dr. Richard T. Lee, an associate professor of medicine at Harvard. The cells were genetically altered to give off a fluorescent green glow if, and only if, they had become heart cells. Looking through the microscope, the researchers saw that glow.
Any medical application is a long way off, Lee says, and he adds that dosing yourself up with vitamin C is not sensible. The importance of the lab work, he says, is that "we have been taught for decades that when your heart cells are dead, they are dead and there is nothing we can do about it. We are excited about anything suggesting that we can grow more heart cells."
The result was certainly unexpected, Lee says. "One of the interesting things about screening is that you somehow find surprises," he says. "We anticipated that nothing would show up. We're quite pleased we got one."
The researchers worked with a line of mouse embryonic stem cells created by the study's first author, Dr. Tomosaburo Takahashi, which had the fluorescent glow gene inserted in them. Tiny wells were filled with stem cells, about 2,000 in each, and the researchers then began exposing the cells to all the compounds described by the U. S. Food and Drug Administration as bioactive, meaning they could interact with living cells. The glow gene went on only in the well where vitamin C was applied.
In addition to that sign, tests showed the vitamin C-treated cells contained cardiac myosin and actin, two proteins involved in the contraction and relaxation of cells that occurs when the heart beats. The tiny clump of cells started to beat, just as the heart does.
The vitamin C action doesn't seem to be related to the beneficial effect of the vitamin on the beating human heart, Lee says. That effect is attributed to the vitamin's ability to neutralize oxidants, naturally occurring molecules that can damage the heart. But other antioxidants, such as vitamin E, did nothing to the stem cells.
"We're working on other compounds that could do the same thing, or even work better," Lee says. "We're also exploring why vitamin C has this activity."
The findings are "quite preliminary," says Dr. Robert O. Bonow, a professor of medicine at Northwestern University and president of the American Heart Association, but they are "a step in the right direction, the kind of progress we need."
One potential problem in ultimately applying the finding to the human heart is that the researchers are working with mouse embryonic stem cells, and the Bush administration has placed tight controls on research with human stem cells. That problem could be overcome if the effect is found to work with adult stem cells, which have a more limited capacity for transformation, Bonow says.
"The tools we gain from work with embryonic stem cells could allow us to use similar tools in work with adult stem cells," he says.
"We would like to work on human stem cells, but ... there are pretty severe restrictions on that work in the United States," Lee says. "But this is very, very far from what people are afraid of."