DNA Heals a Broken Heart

1 August 1997 7:00 pm

When heart muscle or blood vessels are damaged by atherosclerosis, heart attack, or surgery, the body's attempts at repair can often cause further trouble. New growth of muscle cells, for example, thickens blood vessel walls, leading to further heart disease or causing a transplanted heart to fail. Now, Japanese scientists have demonstrated in rodents that gene therapy can alleviate these complications. But experts caution that it will be a while before the technique, described in the current issue of Nature Medicine, can be tried in humans.

The technique is antisense technology, which introduces strands of DNA that can bind to and block the RNA code for particular proteins, preventing cells from making the proteins. In an effort to prevent damage after heart transplants, Jun-Ichi Suzuki from the Shinshu University School of Medicine and his colleagues bathed mouse hearts with antisense DNA to block an enzyme called cdk2 kinase, which stimulates muscle cell growth. By slowing muscle proliferation in the transplanted mouse hearts, the antisense reduced blood vessel thickening by a factor of four.

While the experiments are "elegant," says Jeffrey Isner, a cardiologist at St. Elizabeth's Medical Center in Boston, doctors must figure out a way to boost the efficiency of the antisense approach before they can consider using it as therapy. At the moment less than 1% of the antisense typically gets through the vessel wall into the cell. But even if applications are down the road, Isner hopes the success will "force people to keep thinking about marrying the fruits of molecular biology to cardiovascular pathology."

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