"I was so far down, I had to try," says Brent Benson, who entered a clinical trial last April to rejuvenate his failing heart. Stem cells were taken from the 69-year-old biochemist's hip, processed over several weeks, and pumped as 30 separate injections into parts of his heart muscle that were hibernating--not functioning well, yet not scarred and dead.

The ongoing study is one of many trials testing the ability of an adult's own stem cells--continuously produced and capable of becoming any of a range of cell types--to regenerate heart muscle and restore blood flow.

By one objective measure, Benson's heart has improved. In May, the main pumping chamber of his heart was in distress, enlarged to more than twice its normal size as it labored to compensate for its dwindling strength. Benson was fatigued and had trouble breathing. Six months later, the chamber had shrunk by a third. The heart failure label can't be discarded--Benson's heart is still weak. But he measures his improvement in his reclaimed ability to do physical work, daily at his small farm in Benjamin, Utah, and, in recent weeks, to winterize his family's summer home, some 9,000 feet above sea level.

The lure of stem cells is seductive, but harnessing their ability to take on different roles is just beginning--as is measuring their effect. Researchers often struggle to determine whether a patient's improvement can truly be attributed to a stem cell treatment. "There's such a high placebo effect," says Amit Patel, director of cardiovascular regenerative medicine at the University of Utah and lead investigator in Benson's trial. It's likely that Benson's response is real, given that he lives at such a high altitude, says Patel: "Elevation--that's the ultimate stress test."

No stem cell therapy will wipe out heart failure, experts warn. "Even as a wildly optimistic guy, I don't imagine that anything I do on a single day in the cath lab is going to reverse 30 years of disease," says Douglas Losordo, director of the cardiovascular regenerative medicine program at Northwestern University's Feinberg School of Medicine. He is leading a small heart failure pilot study using stem cells extracted from a patient's own bloodstream.

A few of the unknowns in heart failure trials include how best to deliver the stem cells to the heart, precisely where to place them, and how to keep them from moving elsewhere, as many do. Researchers are also studying which kinds of stem cells are most likely to work--those from a person's own bone marrow, blood, or the heart itself or, someday, "off the shelf" stem cells from other sources. "No evidence out there yet would point a person in one direction or another," Losordo says. It's too new.

Across the spectrum of heart failure therapies, use of stem cells "is the sexiest one," says Patel, but it's "just one component of the entire continuum." To patients with failing hearts and desperate for help, he suggests contacting a major research center that offers many weapons--from surgery to implantable devices to stem cell therapies.

 

 

(c) 2009 U.S. News & World Report