By Martha Gore
January 17, 2001
hen Amy Johnson's husband asked what she wanted for Valentine's Day, Amy's response was, "A mended heart." Johnson is one of many patients waiting for a medical breakthrough that will restore her to the active lifestyle she enjoyed before cardiovascular disease took over.
Fortunately for Johnson and other heart patients, a team of physicians and scientists are working on it. The Sarver Heart Center at the University of Arizona recently put 100 researchers from 26 different medical institutions on the job. All are collaborating to find prevention strategies for cardiovascular disease and to develop innovative treatments, perhaps even a cure. These researchers are working with a variety of different theories -- some brand-new and unconventional, some old and in need of improvement.
What's old is new again
Some researchers are going back to simple questions to find the key to a cure for cardiovascular disease. One important question is, Why can't the heart heal itself when other parts of the body can? Cynthia Adamson, Ph.D., holds a doctorate in physiology and is trying to find a way to get the heart to repair itself, possibly by reprogramming the genetic information inside the cells. According to Adamson, "Muscle cells work the same way as heart cells -- so why do skeletal muscles regenerate and reenter the cell cycles when heart cells don't?" If researchers can find a way to jump-start this process, it would be the ultimate cure.
Dissolving stent tubes
Another researcher working to prevent cardiovascular disease, Marvin Slepian, M.D., is working toward finding a new way to improve an old technique. For years, heart surgeons have been using stents -- wire mesh tubes -- to prop arteries open. Stents are implanted into arteries after angioplasty, the surgical repair of a blood vessel, to ensure blood flow to the heart. Unfortunately, in about 20 percent of cases, the arteries become clogged again. Dr. Slepian would like to create a biodegradable wire-mesh tube to deliver drugs to the artery, bathing the vessel in a substance that would make it healthy again. While coating stents with drugs is common, delivering drugs inside biodegradable stents may make the procedure much more efficient.
Raise the roof with nitric oxide
Another Sarver Heart Center study takes on the classic theory that arteries become clogged because inflammation causes the endothelial cells that line the arteries to contract. The theory says this contraction creates spaces between the cells, providing an entry point for harmful substances in the blood, such as bad cholesterol, which can attach themselves to the artery wall. According to a spokesperson at Sarver, researcher Ann Baldwin, Ph.D., has evidence that what actually happens is a collapse of the scaffolding that keeps the endothelial cells rigid. Baldwin aims to prove that nitric oxide can reconstruct the scaffolding -- a theory that could lead to new therapies for heart and vascular disease.
Can antibiotics reduce the swelling?
Researchers are also interested in determining the effects of antibiotics on the arteries. Scientists will determine whether the antibiotic azithromycin can be used to prevent heart attacks. The hypothesis is that arterial inflammation causes blockages to rupture and that azithromycin might reduce the inflammation in some patients. While the cause of the inflammation is not known, some believe it could be due to the Chlamydia pneumoniae, a bacteria that is the fourth most common cause of pneumonia in the country. Individuals with proven coronary disease -- previous heart attack, bypass surgery, angioplasty, or coronary angiogram showing at least a 50 percent arterial block -- are participating in Sarver's Azithromycin and Coronary Event Study, which will test the antibiotic's effect.
Many aspects of treating cardiovascular disease are being examined, but there is a special emphasis on congestive heart failure, says Steven Goldman, M.D., chief of the section of cardiology at the Southern Arizona Veterans Affairs Health Care System. "While death rates for most forms of cardiovascular disease have been decreasing due in part to the aggressive treatment of acute ischemia (inadequate blood flow to the heart due to arteriosclerosis or other blood vessel injury), the prevalence of heart failure is increasing," Dr. Goldman points out. One potential new treatment Sarver researchers are studying for heart failure uses the thyroid hormone analogue DITPA (3,5-diiodothyropropionic acid), which may improve heart contractions. "If this work proves successful, the use of thyroid analogues to treat heart failure may soon become a reality," says Dr. Goldman.
These are just a few of the studies in process at Sarver Heart Center that will go a long way toward discovering new treatments for heart disease. For Amy Johnson and others still facing a life limited by heart disease or malfunction, the wait is a long one -- but researchers may one day be able to deliver the gift of a healthy heart.
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