Test for Imminent Heart Attacks Cardiologists Discover New Enzyme that Predicts Risk of Heart Attack .
August 1, 2005 — MPO, or myeloperoxidase,is an enzyme produced by white blood cells. High levels of MPO predict a heart attack, the need for invasive intervention, or cardiac death within the next six months with 95-percent accuracy. The FDA has recently approved a simple blood test for MPO.
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August 1, 2005 — MPO, or myeloperoxidase,is an enzyme produced by white blood cells. High levels of MPO predict a heart attack, the need for invasive intervention, or cardiac death within the next six months with 95-percent accuracy. The FDA has recently approved a simple blood test for MPO.
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CLEVELAND--For many people the first sign of heart disease is a heart attack ... And one out of three people who have a heart attack die. The problem? Current blood tests only tell doctors if a heart attack has already happened. Now a new blood test could let doctors know who needs aggressive heart help, before a heart attack happens.
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Fifty-four year old David Lesesky exercises every day with his young family. He has a lot to live for, but not too long ago, his family nearly lost him. "I thought I was running out of wind," he says. "I couldn't catch my breath."
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Lesesky was having a heart attack He knows he is lucky to be alive. He says, "I worked out. I tried to do all the right things. So I thought, if anything, I'm in great shape." This former triathlete's doctors thought so, too. Heart and stress tests didn't pick up a thing, but a dangerous blockage was forming.
Lesesky was having a heart attack He knows he is lucky to be alive. He says, "I worked out. I tried to do all the right things. So I thought, if anything, I'm in great shape." This former triathlete's doctors thought so, too. Heart and stress tests didn't pick up a thing, but a dangerous blockage was forming.
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MPO, or myeloperoxidase is produced by white blood cells, the body's defense system. When there's a dangerous blockage, MPO levels in the blood increase.
MPO, or myeloperoxidase is produced by white blood cells, the body's defense system. When there's a dangerous blockage, MPO levels in the blood increase.
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Cardiologist Stanley Hazen, of Cleveland Clinic, says, "We were able to show that this enzyme called MPO ... that elevated levels of it are seen in patients who are at risk not only for having a heart attack when they present, but also a heart attack or needing bypass surgery or needing angioplasty or dying in the next one-month to six-month period."
A simple blood test -- when performed on patients with the highest MPO levels -- predicted a heart attack, the need for invasive intervention, or cardiac death within the next six months with 95-percent accuracy.
The cardiac MPO test was recently approved by the FDA. It's not widely available yet, but it should start appearing in hospitals across the country soon.
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BACKGROUND: Doctors at the Cleveland Clinic in Ohio have developed a new test to identify those who are in imminent danger of a heart attack by measuring the level of a disease-fighting enzyme in the bloodstream. A start-up company called PrognostiX has received FDA approval to sell the diagnostic test.
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Cardiologist Stanley Hazen, of Cleveland Clinic, says, "We were able to show that this enzyme called MPO ... that elevated levels of it are seen in patients who are at risk not only for having a heart attack when they present, but also a heart attack or needing bypass surgery or needing angioplasty or dying in the next one-month to six-month period."
A simple blood test -- when performed on patients with the highest MPO levels -- predicted a heart attack, the need for invasive intervention, or cardiac death within the next six months with 95-percent accuracy.
The cardiac MPO test was recently approved by the FDA. It's not widely available yet, but it should start appearing in hospitals across the country soon.
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BACKGROUND: Doctors at the Cleveland Clinic in Ohio have developed a new test to identify those who are in imminent danger of a heart attack by measuring the level of a disease-fighting enzyme in the bloodstream. A start-up company called PrognostiX has received FDA approval to sell the diagnostic test.
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HOW IT WORKS: Enzymes are proteins in the body that control metabolism: they convert nutrients into energy and new cell tissue. Enzymes can speed up chemical processes that would otherwise take longer. They are also very specific: each type of enzyme only reacts with one specific compound. High levels of an enzyme called myeloperoxidase (MPO) in the bloodstream can signal a person's near-term risk for heaving a heart attack within months.
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WHAT CAUSES HEART ATTACKS: Heart attack is the leading cause of death in North and South America and in Europe. It is usually the result of prolonged hardening and narrowing of the arteries that direct blood into the heart. When blood vessels are healthy, oxygen-rich blood flows easily to all the muscles and organs of the body. But if they become clogged by the buildup of fatty deposits on vessel walls, blood can be cut off, killing heart muscle cells. This is called coronary heart disease, and it can lead to heart attacks or strokes.
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SIGNS OF A HEART ATTACK:
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Pressure, tightness, or burning chest pain. May extend into the jaw, shoulders, back, or arms
Nausea or vomiting
Sweating
Shortness of breath
Dizziness
Nausea or vomiting
Sweating
Shortness of breath
Dizziness
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Blood Protein Offers Clues To Heart Attack In Seemingly Healthy People
Blood Protein Offers Clues To Heart Attack In Seemingly Healthy People
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ScienceDaily (July 9, 2007) — We've all wondered how a seemingly healthy person can actually be at high risk for heart disease or a heart attack. Now researchers have uncovered a new clue to this mystery. The culprit: myeloperoxidase (MPO), a protein secreted by white blood cells that both signals inflammation and releases a bleach-like substance that damages the cardiovascular system.
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Although MPO is intended to kill harmful bacteria, it may instead inflame the body's arteries and cripple protective substances in the blood, according to a study published in the July 10, 2007, issue of the Journal of the American College of Cardiology (JACC). As a result, long before conventional risk factors set off alarms, elevated MPO levels signal that harmful plaque has been building up.
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Although MPO is intended to kill harmful bacteria, it may instead inflame the body's arteries and cripple protective substances in the blood, according to a study published in the July 10, 2007, issue of the Journal of the American College of Cardiology (JACC). As a result, long before conventional risk factors set off alarms, elevated MPO levels signal that harmful plaque has been building up.
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"We were surprised to find that many years before a cardiovascular event actually occurs, MPO is increased," said Matthijs Boekholdt, M.D., Ph.D., a resident in cardiology at Academic Medical Center in Amsterdam, the Netherlands. "This could open up completely new areas of research and diagnosis. As we learn more about these processes, we hope to be able to identify 'vulnerable blood' as a reliable tool for detecting vulnerable patients."
"We were surprised to find that many years before a cardiovascular event actually occurs, MPO is increased," said Matthijs Boekholdt, M.D., Ph.D., a resident in cardiology at Academic Medical Center in Amsterdam, the Netherlands. "This could open up completely new areas of research and diagnosis. As we learn more about these processes, we hope to be able to identify 'vulnerable blood' as a reliable tool for detecting vulnerable patients."
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Not only does MPO change low-density-lipoprotein (LDL) cholesterol into a harmful oxidized form that can cause atherosclerosis, the "bleach" produced by MPO damages the arteries directly, causing cell death and erosion of the arterial lining, a process that can create unstable plaques. MPO also hampers the protective effects of high-density-lipoprotein (HDL) cholesterol and reduces the availability of nitric oxide, a natural chemical that relaxes the blood vessels.
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Not only does MPO change low-density-lipoprotein (LDL) cholesterol into a harmful oxidized form that can cause atherosclerosis, the "bleach" produced by MPO damages the arteries directly, causing cell death and erosion of the arterial lining, a process that can create unstable plaques. MPO also hampers the protective effects of high-density-lipoprotein (HDL) cholesterol and reduces the availability of nitric oxide, a natural chemical that relaxes the blood vessels.
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Earlier studies in patients with chest pain and heart disease have shown that elevated levels of MPO identify those at highest risk for a heart attack. "The novelty of the present study is that it is the first large-scale study to examine the relationship of MPO to cardiovascular risk in apparently healthy individuals," Dr. Boekholdt said.
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For the study Dr. Boekholdt and colleagues recruited healthy people living in Norfolk, United Kingdom, between 1993 and 1997, as part of a larger community-based research program known as the European Prospective Investigation Into Cancer and Nutrition (EPIC). They took baseline blood samples from each participant and froze the samples for future analysis.
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After an average of eight years, 1,138 EPIC-Norfolk participants had been admitted to the hospital or died from the effects of coronary artery disease (CAD), including heart attack. The researchers matched these patients with study participants who remained healthy throughout the follow-up period, selecting those of the same gender and similar ages and enrollment times.
After an average of eight years, 1,138 EPIC-Norfolk participants had been admitted to the hospital or died from the effects of coronary artery disease (CAD), including heart attack. The researchers matched these patients with study participants who remained healthy throughout the follow-up period, selecting those of the same gender and similar ages and enrollment times.
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The average blood levels of MPO were significantly higher in those who developed heart disease than in those who remained healthy. In fact, when MPO levels were divided into four groups, patients in the highest fourth were 1.49 times as likely as those in the lowest fourth to develop CAD or have a heart attack. When traditional risk factors--blood pressure, LDL and HDL cholesterol levels, body mass index, smoking and diabetes--were taken into account, an MPO level in the highest fourth increased the risk of heart disease by 1.36 times.
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The average blood levels of MPO were significantly higher in those who developed heart disease than in those who remained healthy. In fact, when MPO levels were divided into four groups, patients in the highest fourth were 1.49 times as likely as those in the lowest fourth to develop CAD or have a heart attack. When traditional risk factors--blood pressure, LDL and HDL cholesterol levels, body mass index, smoking and diabetes--were taken into account, an MPO level in the highest fourth increased the risk of heart disease by 1.36 times.
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Equally important, elevated MPO levels signaled increased risk even in those with acceptable levels of LDL cholesterol, HDL cholesterol or C-reactive protein, a widely acknowledged marker of inflammation.
"MPO levels help to identify individuals at increased risk for CAD when traditional risk screening fails," Dr. Boekholdt said.
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"MPO levels help to identify individuals at increased risk for CAD when traditional risk screening fails," Dr. Boekholdt said.
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The search for blood tests to help identify patients at risk for heart attack is a very important one, said Christopher Cannon, M.D., F.A.C.C., who did not participate in the study and is an associate professor of medicine at Harvard Medical School, Boston, MA. "One fascinating aspect of this study is that this marker of inflammation precedes by nearly a decade the development of clinical coronary disease," he said. "This suggests MPO could be used to catch the disease in a very early stage and help in true prevention of CAD.
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"Another interesting aspect of MPO is that it may be a marker for unstable plaque. Even more than the number or severity of coronary plaques, we want to know the risk of plaque rupture, and this evolving new marker may help in that regard. More study is needed, but among the hundreds of markers tested to date, MPO looks like a "keeper" that will one day become part of clinical care," Dr. Cannon said.
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Researchers are continuing to assess the value of MPO in different patient groups as well as in relation to other biomarkers, Dr. Boekholdt said. Key questions include whether, and under what circumstances, MPO should be added to the laboratory tests used to screen for cardiovascular disease, and whether blocking MPO could prevent cardiovascular disease.
The EPIC-Norfolk study is supported by program grants from the Medical Research Council UK and Cancer Research UK, with additional support from the European Union, Stroke Association, British Heart Foundation, and the Wellcome Trust. Some of the measurements in this study were supported by Wyeth. One of the study's authors, Stanley L. Hazen, M.D., Ph.D., is named as a co-inventor on pending patents filed by the Cleveland Clinic Foundation relating to the use of myeloperoxidase as a biomarker for cardiovascular disease.
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Researchers are continuing to assess the value of MPO in different patient groups as well as in relation to other biomarkers, Dr. Boekholdt said. Key questions include whether, and under what circumstances, MPO should be added to the laboratory tests used to screen for cardiovascular disease, and whether blocking MPO could prevent cardiovascular disease.
The EPIC-Norfolk study is supported by program grants from the Medical Research Council UK and Cancer Research UK, with additional support from the European Union, Stroke Association, British Heart Foundation, and the Wellcome Trust. Some of the measurements in this study were supported by Wyeth. One of the study's authors, Stanley L. Hazen, M.D., Ph.D., is named as a co-inventor on pending patents filed by the Cleveland Clinic Foundation relating to the use of myeloperoxidase as a biomarker for cardiovascular disease.
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CardioMPO
