October 4, 2007

Weill Cornell Research Findings Link Nicotine, Atherosclerosis

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Nearly 70.3 million Americans over 12 years of age used tobacco at least once a month in 2004 according to the National Institute on Drug Abuse. This statistic is of increasing concern, as findings recently published by researchers at Weill Cornell Medical College linked nicotine and atherosclerosis.
Nicotine, the addictive ingredient found in tobacco, stimulates reward pathways and releases certain neurotransmitters in the brain, according to the NIDA. These events lead to feelings of pleasure which shortly dissipate, creating a powerful addiction.
Not only is nicotine highly addictive, but it also presents other serious health risks.
“Nicotine itself is particularly hazardous in terms of heart disease and stroke,” explained Prof. Babette Weksler, medicineand co-author of the study.
Specifically, the research, headed by Prof. Daniel F. Catanzaro, medicine, showed the accelerating affects of nicotine on the development of atherosclerosis in young mice.
According to Weksler, “Rather quickly, smoking high nicotine cigarettes has a strong affect on the development of early atherosclerosis lesions and even lowering the amount of nicotine in cigarettes does not avoid these bad effects.”
According to the American Heart Association, atherosclerosis refers to deposits composed of fatty substances, cholesterol, calcium and other products, which cause the arteries to harden. These deposits, known as plaques, can block blood flow and produce clots, which in turn can lead to heart attack, stroke, and gangrene.
In this study, the effects of Eclipse and Quest 3 cigarettes, both “potentially reduced exposure products” containing 0.2 and 0.05 mg nicotine per cigarette, respectively, were compared with those of Quest 1 and 2R4F cigarettes, containing 0.6 and 1.0 mg nicotine per cigarette, respectively, on young mice. 2R4F is a research cigarette supplied by the University of Kentucky. All cigarettes tested had comparable amounts of tar.
The mice were exposed to smoke from the cigarette types in two studies of varying length. Both studies concluded that mice exposed to smoke from high nicotine cigarettes Quest 1 and 2R4F developed greater areas of atherosclerotic lesions than did mice exposed to the lower nicotine cigarettes Eclipse and Quest 3. The control group, consisting of mice that were not exposed to smoke, developed the fewest lesions.
Additionally, researchers found increased levels of iPF2alphaV, a marker for oxidative stress linked to atherosclerosis in humans, increased proportionately with nicotine content. This finding points to nicotine as a cause of oxidative stress and as an inhibitor of nitric oxide.
“Nicotine acts in the artery wall itself to block enzymes that normally produce nitric oxide or to inactivate nitric oxide once it’s already produced,” Weksler further explained.
This is especially dangerous, according to Weksler, as nitric oxide serves as a protective mechanism that keeps blood vessels relaxed, prevents platelets from clumping and sticking to blood vessels, blocks the multiplication of cells in the walls of blood vessels and prevents clots from forming on the blood vessel surface.
Although some cigarettes, such as the Eclipse and Quest, claim to be less hazardous, they are “probably more harmful than the manufactures thought they were” Weksler suggested.
Eclipse cigarettes claim to be safer by heating tobacco rather than burning it, yet the American Cancer Society urged R.J. Reynolds Tobacco Company in 2004 to pull Eclipse off the market, citing evidence that the cigarettes produce greater amounts of cancer causing chemicals than other available low tar cigarettes.
Additionally, the R.J. Reynolds website’s claim that, “Nicotine in tobacco products is addictive but is not considered a significant threat to health,” may prove inaccurate, as suggested by Weill Cornell’s new findings.
Quest cigarettes, also an alternative to traditional cigarettes, are made from modified tobacco offering various levels of nicotine.
While Quest claims that these cigarettes allow smokers to reduce their nicotine intake, Catanzaro argued, “It doesn’t work this way because one of the main reasons that people smoke is to get their nicotine. So if you’re smoking a low nicotine cigarette, what most people do is just suck harder or smoke more.”
Smoking cessation products, specifically nicotine replacement therapy, may also need to be reexamined.
“If [nicotine patches and gum] are the only way to get you not to smoke, it’s probably better than nothing, but it may not be quite as safe as it was thought,” Weksler said.
Despite this research, Jennifer May, a representative of GlaxoSmithKline Health Care, confidently asserted the safety of nicotine replacement therapy. GlaxoSmithKline Health Care manufactures products such as NicoDerm CQ and Nicorette Gum.
“More than 100 clinical trials involving over 35,000 participants and extensive consumer use over more than 20 years have proven the safety and efficacy of NRT [nicotine replacement therapy],” May said.
Catanzaro urged, “We just have to drive home a public awareness message that nicotine in it of itself is bad for you it just adds to the list of the different ways in which tobacco and smoking are harmful for you.”