GETTY – STOCK IMAGES
New medical research suggest that some heavy smokers can be immune to smoking-related heart disease
Smoking-related heart disease is tied to the effects of a single gene, which, when lost, leads of a plaque buildup in heart arteries, eventually leading to the disease.
However, new research suggests that there are some people who are immune to smoking-related coronary heart disease because their copy of the gene works differently, and is not affected by smoking.
Dr Muredach Reilly of Columbia University Medical Center, said: “Our finding suggest that interventions to inhibit this enzyme would be particularly beneficial for smokers, and they may also prove useful for anyone at heightened risk of coronary heart disease.”
The study, the largest of its kind, was published online today (Tues) in the journal Circulation.
Cigarette smoking is known to cause about one in five cases of coronary heart disease, and is linked to approximately 1.6 million deaths worldwide each year, but the precise mechanisms have not yet been discovered.
Our finding suggest that interventions to inhibit this enzyme would be particularly beneficial for smokers
Researchers pooled genetic data on more than 140,000 people from 29 previous studies.
They analysed 45 small regions of the genome that have been previously associated with a heightened risk of CHD.
The analysis showed that a change in a single DNA “letter” on chromosome 15, near the gene that expresses an enzyme produced in blood vessels, was associated with a 12 percent reduction in heart risk in non-smokers.
GETTY – STOCK IMAGE
Smoking-related heart disease is tied to the effects of a single gene
GETTY – STOCK IMAGE
When lost, it leads of a plaque buildup in heart arteries, eventually leading to the disease
However, smokers with this same variation had only a five percent lower risk of coronary heart disease.
DNA variations located near a gene sometimes inhibit the gene’s activity, causing below-normal levels of the protein it produces.
In this case, the researchers discovered that the single-letter DNA variation that protected patients from heart disease resulted in a significant decline in the production of ADAMTS7, the plaque that wrecks the heart’s arteries.
When the researchers applied a liquid extract of cigarette smoke to coronary artery cells, the cells’ production of ADAMTS7 more than doubled, supporting the conclusion that smoking may counteract the genetic protection by increasing the level of ADAMTS7 in the artery wall.
GETTY – STOCK IMAGE
Some people are immune to smoking-related heart disease as their copy of the gene works differently
Lead author Dr Danish Saleheen, assistant professor of biostatistics and epidemiology at the Perelman School of Medicine at the University of Pennsylvania, said: “This has been one of the first big steps towards solving the complex puzzle of gene-environment interactions that lead to CHD.”
In future studies, the researchers hope to establish exactly how the ADAMTS7 variants protect against coronary heart disease and how cigarette smoking affects the activity of the gene that produces the enzyme.
They are also hoping to discover whether reducing or inhibiting ADAMTS7 can slow the progression of atherosclerosis due to cigarette smoking.
Dr Reilly added: “This study is an important example of the emerging field of precision medicine and precision public health.
“Through these large-scale genetic studies, we’re beginning to understand the genetic variations that drive risk in response to certain environmental exposures or lifestyle behaviours.
“Not everyone reacts the same to the same exposures or behaviours. For example, some people who don’t exercise develop diabetes while others do not.
“So, instead of saying there are rules for everybody, we can specify which interventions will be especially beneficial for specific populations or individuals and focus our health resources more efficiently.”
Daily Express :: Life and Style Feed
