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Monday, July 11, 2005''Most of the studies in the past have revolved around cholesterol,' but other factors also must be involved because cholesterol levels are normal in many heart attack victims, Berliner said. Scientists have long suspected that one such factor might be oxidized phospholipids, a type of fat that's a major component of LDL or ''bad cholesterol.' Research in animals has found that this fat, floating in the bloodstream, contributes in many ways to blockage formation. The new research, led by Dr. Sotirios Tsimikas at the University of California, San Diego, is the first to show the same is true in people. Tsimikas studied 504 people being tested for clogged arteries. Among those 60 or younger, people with the highest levels of oxidized phospholipids were three times more likely to have blockages than those with the lowest levels." The study compared the degree of coronary artery stenosis as seen on cardiac catheterization with the levels of oxidized phospholipids measured just before the catheterization. They found that the increase in levels of oxidized phospholipids was just as strong a predictor of the degree of stenosis as male sex, hypertension, age, and LDL cholesterol - the levels of which we now use to guide our therapy recommendations for lowering cholesterol. The oxidized phospholipids are actually components of LDL that are involved in the inflammatory process that occurs in the walls of a diseased artery. This inflammatory process - part of the body's repair process - also involves, unfortunately for us, an increase in the tendency to make clots along the sides of the blood vessel wall. This clotting tendency also happens to be modulated by the oxidized phospholipids. They serve as signals to the body that a particular cell in the artery wall needs fixed. Physiologically, it makes sense that measuring these types of lipid directly would give us a better understanding of a person's risk for heart disease - especially in younger people for whom the ravages of time have yet to act on a blood vessel. So, doesn't that indicate that we should exercise caution in recommending high doses of expensive cholesterol lowering medication to lower LDL levels until we have a better understanding of the physiology and biochemistry of cholesterol? I think it does! P.S. The study also found that levels of C-reactive protein, a much less specific marker for inflammation, did not correlate with the degree of coronary artery stenosis. posted by Sydney on 7/11/2005 07:45:00 AM 0 comments 0 Comments: |
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