Stem cell therapy to be tested on heart patients

WASHINGTON -- A clinical trial to test the safety of treating heart attack damage with stem cells is about to get underway, following a study that showed the therapy helped in pigs.

Two patients have been enrolled so far at Johns Hopkins Hospital in Baltimore, and a total of 48 are expected to take part across the country, said Dr. Joshua M. Hare, who is leading the study.

''Any time something new comes along, there is a sense of excitement, and that's the feeling that we have. And we obviously hope it will be borne out by the results," Hare said in a telephone interview.

The process uses adult stem cells taken from bone marrow. These cells, called mesenchymal cells, have been shown to give rise to a variety of cell types. While they don't have the potential to develop into as many cell types as embryonic stem cells, using them avoids the controversy of taking cells from a human embryo.

In tests in pigs, stem cells taken from another pig's bone marrow were injected into the animal's damaged heart. After just two months, the stem cells had helped restore heart function and repaired damaged heart muscle by 50 percent to 75 percent.

Those results are reported in today's issue of Proceedings of the National Academy of Sciences.

The work is an early indication that stem cells may have therapeutic value in treating heart attacks, but a lot of work still needs to be done, said Dr. Sidney Smith, cardiology chief at the University of North Carolina at Chapel Hill.

The planned tests in humans are a Phase I trial, meaning that the goal is to make sure the procedure is safe. Only after safety is established will the scientists move on to a Phase II trial to see whether it works as well in people as in pigs.

But researchers will be checking to see whether the procedure is helping people. Hare said study participants will be watched for two years. Six months after the treatment, they will undergo an MRI to check their heart function.

Hare said he hopes that will be taking place by mid-2006.