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Heart-Disease Test By Age 30?

Posted on: Tuesday, 14 November 2006, 18:01 CST

By CHRISTINE DELL'AMORE

In the future, doctors may able to detect signs of early-onset coronary artery disease in the blood of patients as young as 30, researchers reported Tuesday.

With a type of blood profiling called metabolomics, which looks at the body's genetics and biochemistry simultaneously, scientists are now able to get a snapshot of how complex human biology works. For example, modern ultra-sensitive technologies can pick up tiny pieces of cellular trash, or metabolites, which are byproducts of cellular processes in the blood.

Analyzing these leftovers can provide doctors with much-needed indications about a person's risk for coronary artery disease, or CAD, which is a player in cardiovascular disease, the leading cause of sickness and death worldwide, said Dr. Svati Shah, an assistant professor of medicine at Duke University Medical Center in Durham, N.C.

The fact we can measure such small amounts of molecules with such accuracy in and of itself is amazing, said Shah, who presented her research at the annual scientific sessions of the American Heart Association in Chicago.

However, these findings are still a work in progress. They have not undergone peer review, and they may change after future research is done.

CAD occurs when blood flow through the coronary arteries is blocked or narrowed by fatty buildup. A lack of blood flow may create chest pain or shortness of breath, and a total blockage leads to a heart attack. Some of the common risk factors for CAD are smoking, high blood pressure, high cholesterol and obesity. But some with none of these conditions will still develop the disease, a phenomenon that is not fully understood.

For instance, it's known that CAD runs in families, but scientists don't know the genetic basis of the disease. Shah suspected metabolic tests could begin to demystify how the disease operates in the body, and perhaps lead to early identification and treatment of the condition.

In their recent study, Shah and colleagues randomly selected 80 Caucasian men and women from five different families affected by early-onset CAD. Twenty participants had early-onset CAD, and the rest were siblings or children at risk for developing the disease. The participants, who averaged between 30 and 40 years of age and lived mostly in the southeastern United States, didn't share the same cardiovascular risk factors, such as overweight and high cholesterol. Some were slim and otherwise healthy.

The team found the metabolites, or the bits of trash in the blood, seemed to be inherited in families with a high likelihood of having CAD. Shah and colleagues discovered different clusters of metabolites among the five families, which were similar within their kin but not between strangers.

However, the sample was small and the results cannot be generalized to the entire U.S. population.

The researchers also developed some working hypotheses of how the disease operates in the body. It may be that people with predispositions to CAD have cells that metabolize through certain biological pathways. There are three of these potential pathways: insulin signaling; arachidonate, which is a type of inflammatory pathway; and nitric oxide.

Someday, doctors could identify which pathway the body relies on to develop CAD, and then target that pathway with drug treatments, Shah said.

In fact, testing metabolites could provide doctors with a completely new set of tools to predict risk of CAD in patients. Physicians could administer the test as part of a blood test during a regular physical exam, and if a problem is found the doctor could then tailor preventive treatments and lifestyle changes.

The current methods for detecting CAD are costly, lack sensitivity and specificity and don't get to the core of what's going on biologically, Shah said. The gold standard, invasive method for testing CAD is an angiogram, in which a doctor threads a catheter into the artery and then X-rays the chest. Other methods are non-invasive; for instance, a stress test measures how the heart of a patient running on a treadmill handles exertion.

Shah plans to validate her findings in a larger study, as well as figure out which genes are responsible for the strong heritability of the disease.

Metabolomics is an exciting area, not only because of the excellent precision of the technology to detect metabolites, but because of the opportunity to pre-emptively attack CAD in patients, said Donna Arnett, professor and chair of the department of epidemiology at the University of Alabama at Birmingham.

If we could develop screening tools for who is most likely to develop CAD, a sudden cardiac death wouldn't have to be someone's only warning notice, Arnett said.

Source: United Press International

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