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Gordon Tomaselli – Biomarkers for Cardiac Disease

It's a shocking figure: Every 37 seconds, someone in the United States dies from cardiovascular disease.

An estimated 5.7 million Americans live with heart failure, a chronic, progressive condition in which the heart muscle cannot pump blood efficiently enough to meet the body's workload. Every one of these individuals is a prime candidate for sudden cardiac death (SCD) – an unexpected, abrupt loss of heart function that occurs minutes after symptoms appear.

For many of the 670,000 patients annually diagnosed with heart failure, the recommended course of action is surgically implanting a cardiac defibrillator, which briefly shocks the heart to correct errant rhythms.

Some 2 million Americans have defibrillators, but according to Dr. Gordon F. Tomaselli, Director of Cardiology at the Johns Hopkins University School of Medicine, less than 5 percent of these implanted devices ever need to fire an electrical shock.

"It's really an insurance policy," Dr. Tomaselli says. "Right now, we can't predict who is going to die from SCD." So the prudent step for many heart failure patients and their physicians is a defibrillator implant – just in case it is ever needed. Hundreds of thousands of them are surgically inserted each year.

Dr. Tomaselli is searching for a more effective and less costly way to protect heart failure patients from sudden cardiac death. He also wants to identify the patients most likely to require repeated hospitalization for their weakening hearts.

Now a $600,000 ARRA Challenge Grant from NIH is giving Dr. Tomaselli the opportunity to sort through blood-borne biomarkers and identify a handful of genes associated with potentially lethal heart failure and cardiac hospitalizations.

In ARRA terminology, this research is "shovel-ready" because of an ongoing Hopkins study of 1,200 cardiac patients with implanted defibrillators. Thus, Dr. Tomaselli has the all clinical and laboratory data he needs to begin his biomarker investigation and complete his research within ARRA's two-year window.

Blood samples from patients in the defibrillator study are being processed at the Johns Hopkins Microarray Core Facility, where sophisticated computers analyze the 1,200 sets of DNA samples and compare how hundreds of thousands of genes transmit information.

In particular, Hopkins researchers are interested in two key genetic molecules – messenger-RNA, which delivers DNA information and then helps produce proteins, and micro-RNA, which regulates and inhibits genetic expression. Both of these are believed to play vital roles in cardiovascular and muscle disease.

It is Dr. Tomaselli's hypothesis that the microarray analysis will lead to the discovery of biological markers in the two molecules that signal when something bad is likely to happen in a patient's cardiovascular system. If so, he says, "We can develop a specific, non-invasive blood test" that will tell physicians which of the 2 million patients with heart failure actually need implantable defibrillators.

Such a test could sharply reduce the number of high-cost, hazardous cardiac defibrillator surgeries. The test might also identify high-risk heart failure patients so cardiologists can take proactive therapeutic steps to prevent repeated hospitalizations or long hospital stays and increase a patient's longevity and quality of life.

There's an added plus if the analysis shows these genetic biomarkers are intimately tied to the development of cardiac disease. Then Dr. Tomaselli's research team can take the next, exciting step: Designing drug therapies that will prevent both heart failure and heart-tissue weakness.

This article originally appeared on the Johns Hopkins University website. Reposted with permission.

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  • Bioengineering
  • Biotechnology
  • Cardiovascular
  • Clinical Research
  • Genetics
  • Heart Disease
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