January 24, 2011

Eva Gusnowski

Eva Gusnowski, PAH, cigarettes


Let me start off by saying that I’m not a smoker, yet I still found this pretty alarming. I knew that my body was pretty efficient at making energy, new cells and falling asleep at my desk.  But I never would have guessed that it would be so efficient at a process that can cause damage to DNA.


Polycyclic aromatic hydrocarbons (PAHs) are important carcinogens (cancer-causing agents) found in cigarette smoke.  In fact, the burning of tobacco results in a cocktail of various PAHs, many of which are potent carcinogens (an especially nasty one is called benzo[alpha]pyrene, or BaP).  PAHs are broken down in the body to compounds called diol epoxides, and these byproducts are actually what result in DNA mutations.  After all of the media exposure and non-smoking campaigns, it should come as no surprise when I say that the accumulation of mutations can eventually result in cancer. 


A chemical called phenanthrene (Phe) is a PAH that is broken down in the body using the same metabolic pathway as BaP.  The resulting diol epoxide byproducts from Phe breakdown are similar to BaP byproducts, but are non-carcinogenic.  Therefore, monitoring the breakdown of Phe in the body can be used as an indicator of the activity of the PAH breakdown pathway. 


Recently, Phe was added to cigarettes so researchers could monitor the activity of the PAH pathway in human test subjects after cigarette smoke inhalation.  Alarmingly, the level of Phe diol expoxides (the end products of the PAH breakdown pathway) in the blood peaked between 15-30 minutes after a cigarette was smoked.  This means that in as little as 15 minutes after you smoke a cigarette your body is making carcinogenic byproducts and your DNA can be attacked.  Lung tissue therefore has the potential to suffer near immediate DNA damage after smoking. 


Talk about unwanted efficiency.  Considering that an estimated 90% of lung cancers are the result of cigarette smoke, this is definitely something to think about before lighting that cigarette and taking your next PAH-uff. 



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