According to the American Society of Cardiology Circulation: Cardiovascular Genetics, smoking can leave a "footprint" in the human genome through DNA methylation (regulatory gene activity).
New findings indicate that DNA methylation can serve as an important indicator of exposing the history of individual smoking and providing researchers with potential targets for developing new therapies.
Tobacco Testimonials : Copyright American Heart Association
"The above results are important because, as one of the mechanisms that regulates gene expression, methylation affects the expression of the gene, which may imply clues to the course of the disease associated with smoking." The author of the article, North Carolina "It is also important that the effects of smoking on smokers' DNA are still there," said Dr. Stephanie J. London, vice president of the National Institute of Environmental Health's National Institute of Health, National Sanitation Institute, National Sanitation Institute. The country has significantly reduced the number of smokers by means of smoking and smoking, but smoking is still the primary cause of death in the world. Even if you have quit smoking for decades, people who have smoked cigarettes are still sick, including some cancer, chronic obstructive pulmonary disease and stroke risk. However, the molecular mechanism that causes this long-term effect of smoking is unclear. Previous studies have linked the DNA methylation site of the gene to coronary heart disease and lung disease, suggesting that DNA methylation may play a role in this process Important role.
The researchers were genetically engineered by 16% of the 16,000 volunteers from the community of the heart and the Aging Genetic Epidemiology Community (16 groups of the Cohorts for Heart and Aging Research in GeneticEpidemiology (CHARGE) Consortium) The site was subjected to a meta-analysis, which included a set of samples from the Framingham Heart Study that began tracking in 1971.
The researchers compared the DNA methylation sites of people who are still smoking and those who have quit smoking to people who have never smoked cigarettes. They found that smoking-related DNA methylation sites involved more than 7,000 genes, equivalent to one-third of the known number of human genes.
For those who have quit smoking, most of the DNA methylation sites return to the same level as those who have never smoked, five years after quitting.
However, some DNA methylation sites still exist after 30 years of quitting.
The most statistically significant methylation sites are located on genes that are closely related to many diseases, such as cardiovascular disease and specific cancers.
The researchers point out that some of these intractable methylation sites may be a sign of some potentially important genes that are associated with an increased risk of specific disease among smokers who have quit smoking. The discovery of smoking-related DNA methylation sites has increased the possibility of developing biomarkers for assessing the history of smoking in patients and provided potential for the development of treatments for these methylation sites.
Researchers point out that Meta-analysis does not primarily test the long-term effects of smoking, but the effect of smoking on DAN methylation.
"Our research has found irrefutable evidence for the molecular mechanisms that have long-term effects on smoking, which can last up to 30 years." The first author of the Hebrew Aging Institute, Harvard Medical School faculty Dr. Roby Joehanes said, "The good news is that once the cessation of smoking, most of the DNA methylation signal in 5 years will return to the same level with never smokers, that is, after being damaged by tobacco, the body will try to self repair."