The largest national stem cell study for heart disease showed that transplant subjects also experienced fewer deaths than those who didn't receive stem cells.

In the 12-month Phase II, double-blind trial, subjects' own purified stem cells, called CD34+ cells, were injected into their hearts in an effort to spur the growth of small blood vessels that make up the microcirculation of the heart muscle.

According to researchers, the loss of these blood vessels contributes to the pain of chronic, severe angina. "This is the first study to show significant benefit in pain reduction and improved exercise capacity in this population with very advanced heart disease," said principal investigator Dr. Douglas Losordo at the Northwestern University Feinberg School of Medicine.

He also said that this study provides the first evidence that a person's own stem cells can be used as a treatment for their heart disease. However, he cautioned that the findings of the 25-site trial with 167 subjects, require verification in a larger, Phase III study.

The stem cell transplant is the first therapy to produce an improvement in severe angina subjects' ability to walk on a treadmill. Twelve months after the procedure, the transplant subjects were able to double their improvement on a treadmill compared to the placebo group.

It also took twice as long until they experienced angina pain on a treadmill compared to the placebo group, and, when they felt pain, it went away faster with rest. In addition, they had fewer overall episodes of chest pain in their daily lives.

In the trial, the CD34+ cells were injected into 10 locations in the heart muscle.
A sophisticated electromechanical mapping technology identified where the heart muscle is alive but not functioning, because it is not receiving enough blood supply.