Science News

Stem cells get to the heart of angina

Researchers in the US have found that patients with angina who received injections of their own stem cells into the diseased heart muscle showed considerable improvements in their symptoms. Cardiologist Douglas Losordo and his colleagues recruited 24 patients aged 48-84 with severe (grade 3 or 4) angina; on enrollment the patients were symptomatic upon mild exertion; even brushing their teeth was sufficient to provoke chest pain. The team harvested stem cells from the patients by injecting them with a hormone called G-CSF. This encourages bone marrow stem cells to grow and spill over into the bloodstream from which they can easily be collected.

The team used a molecular marker known as CD34 to single out the stem cells, which were then injected into the heart muscle in some of the patients. Others received a placebo. The injections were placed at sites in the heart known as "hibernating myocardium", which are regions of the muscle revealed by scans to contain viable muscle which is largely shut down (asleep) due to poor oxygen and glucose supply. Three to six months after the therapy the patients given stem cell injections had improved significantly. Some of them went from barely being able to make it to the toilet to managing two flights of stairs. The team suspect that the injected stem cells promote the formation of new blood vessels within the muscle, helping to boost the supply of oxygen and therefore increasing the workload that the heart can handle.

"Our goal is to reconstitute the microcirculation, get the blood back into the tissue and alleviate the symptoms," says Losordo.

1st Jul 2007