Researchers at the Rush University Medical Center are excited by the findings of their Phase I clinical trial, which suggest that heart attack patients fare much better if they receive a prompt injection of adult stem cells. The study provides some of the first evidence that adult stem cells, in addition to embryonic stem cells, have the capacity to differentiate into various types of mature cells.

In the study, 53 patients were injected with adult stem cells within 10 days of having a heart attack and their recovery was compared to those who received placebo. The stem cells, known as mesenchymal cells, had come from the bone marrow of healthy adults. These cells are particularly advantageous because they don’t trigger an immune response – therefore, a match between donor and recipient is not required.

Six months after receiving their respective treatments, the patients were analyzed to see how their recovery was progressing. The hearts of those who received the stem cell injections were about four times healthier overall than those who received placebo. The hearts of the experimental group were also better at pumping blood with each beat and they had 25% fewer irregular heartbeats (arrhythmias) than those in the control group.

“The results point to a promising new treatment for heart attack patients that could reduce mortality and lessen the need for heart transplants,” said Gary Schaer, lead author of the study. The researchers reported that there were no serious side effects associated with the treatment.

How do the stem cells exert their effect? Schaer explains that “[i]t is suspected that these stem cells may take part in the growth of new blood vessels to bring more oxygen to the heart and help reduce the scarring from a heart attack.”

The study provides convincing evidence that adult stem cells, like embryonic stem cells, are able to differentiate into various mature cell types, like heart and blood vessel cells. “This study suggests that adult bone marrow derived stem cells are more flexible than previously thought," said Schaer. "If the benefits and safety are confirmed in the ongoing Phase II trial, we may soon have a remarkable new therapy for patients with a large heart." The University is currently in the early stages of this second phase of the clinical trial.

The author also suggests that, once more is known about the process, “hospitals might be able to keep frozen adult stem cells on hand for speedy use in treating heart attacks.”

The results of the study were reported in the December 8, 2009 issue of Journal of the American College of Cardiology.