• Health reform
• EMRs
• Medicare
• Liability
• AMA House
• » More

• Contract Language
• Ethics Forum
• In the Courts
• Practice Management
• Technically Speaking
• » More

• Issue dates
• Regions
• Health plans
• Sections
• News briefs
• Columns
• Editorials
• Letters
• Series
• Writers
• Other years

• Search tips
• Email alert
• RSS
• Mobile
• Subscribe
• Institutions
• Staff directory
• Advertising
• Permissions
• Reprints
• News media
• Site guide
• Useful links
• About
• Premium
• Contact

• AMA Wire
• CPT
• DMPHP
• JAMA
• JAMA&Archives
• news@JAMA
• Virtual Mentor
• Physician jobs

Progenitor cells indicative of lower cardiac risk?

A study suggests cell levels may signal the chance of developing heart disease and lead to new treatments, but experts say more research is needed.

By Victoria Stagg Elliott, amednews staff. March 10, 2003.

• PRINT|
• E-MAIL|
• RESPOND|
• REPRINTS|
• SHARE
•  

The blood levels of endothelial progenitor cells -- a type of adult stem cell that repairs damage to the walls of blood vessels -- may indicate a person's risk of developing heart disease or stroke, according to a study published in The New England Journal of Medicine Feb. 13.

Scientists from the National Heart, Lung and Blood Institute studied 45 healthy men and found that their levels of these cells correlated with Framingham Heart Study risk scores for developing cardiovascular disease.

To date, most research regarding heart disease risk has relied on factors such as high blood pressure or excess body weight -- both of which are evidence that damage is under way. These researchers took a different tack by searching for factors that could be counteracting rather than causing damage to the cardiovascular system.

"If this hypothesis that we're trying to advance is correct, then it does not actually look at the injury side of the equation," said Toren Finkel, MD, PhD, co-author of the study and chief of NHLBI's cardiovascular branch. "It looks more at the repair side of the equation. Those two sides might be linked together, but they may not be."

Researchers suggested that this finding could eventually lead to new screening modalities and possibly new treatments.

"It's possible that, some day, doctors may be able to test a person's risk of cardiovascular disease by taking a blood sample and measuring these cells," said Dr. Finkel. "If the level is too low, an injection of endothelial cells might boost the body's ability to repair itself and prevent more blood vessel damage."

But experts and researchers agreed that the test was far from ready for regular use because it is currently too time-consuming and costly. Also, this study was not large enough to prompt a wide-scale change in practice.

"The group was very small, and it was a very well-controlled population," said Dr. Jonathan Hill, lead author of the study and an NHLBI fellow. "It remains to be seen whether there will be this degree of correlation in larger studies with a more heterogeneous population."

However, the eventual utility of testing for levels of these cells as a screening tool is a contentious matter. Some experts doubt it would add anything to current assessment protocols.

"I don't think we'd use this to screen for blood vessel disease," said Robert Bonow, MD, president of the American Heart Assn.

But others believe it has great potential to be a warning sign long before risk factors such as cholesterol are measurable.

"This may be a screening for the earliest signs of abnormalities in the blood vessels, and we might be able to intervene even earlier," said Jose Missri, MD, medical director of St. Vincent's Regional Heart and Vascular Center in Bridgeport, Conn.

Future promise

Experts are most excited about the research's great potential for new treatment approaches. Medications that can bump up production of these repair cells are already in existence. They are primarily used for cancer patients undergoing chemotherapy, although several clinical trials are under way to determine their possible impact on heart disease.

"The bottom line is that it does seem like there's something to this," said Cindy Grines, MD, a cardiologist at Beaumont Hospital in Royal Oak, Mich. "And it's possible that if you stimulate the production of these circulating cells that perhaps you could have beneficial effects in a patient."

The use of this type of adult stem cell for repair also sidesteps many of the ethical questions and medical quandaries created by transplanting embryonic cells. With autologous transplant or increased generation prompted by medication there would be no need for the immune-suppressive drugs required if the cells came from another source.

There are, however, many unanswered questions.

It's unclear how measuring levels of these cells, if an easier test becomes available, may fit in with the assessment of other risk factors.

"In our hearts, we think it's very distinct from cholesterol and [C-reactive protein], although we haven't proven that definitively," said Dr. Finkel.

It's also unknown whether increasing the number of these progenitor cells might, in reality, result in deleterious or beneficial effects.

"It's still very, very early, and I don't think we should be doing this in patients yet until we have more experimental data," said Dr. Bonow, who is also chief of cardiology at Northwestern University in Chicago.

Back to top

 ADDITIONAL INFORMATION: