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Mitochondrial DNA content increase in response to cigarette smoking
Brett G Masayesva1, Elizabeth Mambo, Rodney J Taylor
1Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins Medical Institutions, Baltimore, MD 21287-0910, USA.
Summary
Smoking significantly increases mitochondrial DNA (mtDNA) content, a change that persists long after cessation. This suggests long-term cellular damage from tobacco smoke exposure.
Area of Science:
- Biochemistry
- Genetics
- Environmental Health
Background:
- Mitochondrial DNA (mtDNA) content increases and mitochondrial function declines with aging and exposure to DNA-damaging agents like tobacco smoke.
- Smoking is a major public health concern linked to various diseases.
Purpose of the Study:
- To investigate the association between smoking and alcohol consumption and changes in mitochondrial DNA content.
- To quantify alterations in mtDNA content in relation to smoking history and other demographic factors.
Main Methods:
- A cross-sectional study involving 604 individuals with varied smoking and alcohol exposure.
- Quantification of nuclear (beta-actin) and mitochondrial DNA (cytochrome c oxidase I and II) using real-time PCR on DNA extracted from saliva cells.
- Multivariate regression analyses to correlate mtDNA content with age, smoking history, ethanol intake, and other variables.
Main Results:
- Smokers and former smokers showed a significant increase (31-34%) in mtDNA content compared to never smokers, independent of age, alcohol intake, and income.
- Increased mtDNA content was positively associated with pack-years of smoking in a dose-dependent manner.
- No statistically significant association was found between tobacco cessation interval and mtDNA content, even after 21 years.
Conclusions:
- Smoking is strongly associated with increased mitochondrial DNA content in a dose-dependent manner.
- These smoking-induced mtDNA alterations persist for decades after smoking cessation, indicating long-term cellular damage.
- Mitochondrial DNA changes serve as a potential biomarker for long-term effects of smoking.
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