North Carolina State University News Services
Campus Box 7504
Raleigh, NC 27695
(919) 515-3470
Media Contacts:
Dr. James Otvos, 919/515-5724, [email protected]
Alexandra Mordecai, News Services, 919/515-3470, [email protected]
November 5, 1997
New Blood Test More Accurately Measures Risk of Heart Disease
FOR IMMEDIATE RELEASE
A North Carolina State University biochemist has developed a blood test that provides a quicker and much more accurate way of predicting the likelihood of heart disease than other blood analysis methods.
Dr. James Otvos's patented technique already is proving beneficial to drug companies, which are using it in research. After Food and Drug Administration approval, Otvos hopes physicians will find the technology useful in pinpointing at-risk patients and prescribing prevention measures.
His method uses nuclear magnetic resonance (NMR) to analyze blood's lipoproteins, the particles that carry fats and fat-like substances such as cholesterol through the bloodstream. And in case you're thinking, "Who cares about lipoproteins? What about my cholesterol?," Otvos points out that it's not cholesterol, per se, that's really important; rather it's the size and type of lipoproteins that count in predicting heart disease probability.
"In fact," he says, "two people with the same proportions of so-called good cholesterol (high density lipoprotein, or HDL, cholesterol) to bad cholesterol (low density lipoprotein, or LDL, cholesterol) can have very different risks of coronary heart disease. If one has predominately small LDL particles and the other has predominately large LDL particles, the first person has a three-fold greater risk of heart disease. Small LDL particles are the riskiest."
Drugs and other preventive measures already exist to help reduce the incidence and severity of coronary heart disease, which killed 487,490 people in the United States in 1994 and is the nation's single leading cause of death. But prediction has been difficult because it has been hard for laboratories to accurately and swiftly analyze the amount of each lipoprotein type and size, and simply measuring the amount of HDL versus LDL has proven disappointingly inaccurate in predicting heart disease. Many patients have been misclassified -- some who need medication are not receiving it, and some who do not need it are taking it unnecessarily.
Otvos's NMR method works in about one minute, and the machine can analyze more than 1,000 blood samples a day. Other methods take hours to days, and they require the physical separation of lipoprotein particles, which can adversely affect the accuracy of test results.
A company, LipoMed, was formed to commercialize Otvos's technology. Dr. Stephen Markham, co-principal investigator of NC State's Technology Education and Commercialization program, worked with Otvos to facilitate the process. The university's Office of Technology Transfer and Industry Research negotiated a license agreement with LipoMed for patent rights. LipoMed is adjacent to Wake Medical Center in Raleigh.
As for the confusion over cholesterol, Otvos says, "People talk about cholesterol because historically there was sort of an analytical veil over blood lipoproteins. If someone had figured out earlier how to directly measure lipoproteins, then we never would have been talking so much about cholesterol."
Otvos offered this comparison: Try thinking of blood as a deep, dark pool; lipoproteins are fish, and cholesterol molecules are shrimp inside the fish. Blood analysts 40 years ago would reach blindly into the water and squeeze all the fish until the shrimp popped out, then count the shrimp: total cholesterol.
Twenty-five years ago, they would reach into the pool, feel the fish and divide them into two groups -- guppies (high density lipoproteins) and pirhanas (low density lipoproteins). Then they would squeeze the shrimp out of each group and count them: HDL and LDL cholesterol.
Otvos's technique allows researchers to see into the pool and assess not only the number, but also the size of pirhanas and guppies. The number of shrimp inside the fish doesn't matter; the number of dangerous small pirhanas does. "Cholesterol is cholesterol," Otvos says. "It is lipoproteins that tell us about risk of heart disease."
-- mordecai --
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