Credit: news.bioscholar.com |
Asthma in the Smoker’s Grandchildren
The
dangers of smoking on smokers and their children are widely known but new
research demonstrates that nicotine exposure also causes asthma in the smoker’s
grandchildren.
Asthma
is a major public health problem. It is the most common chronic disease of
childhood. While there are many factors which contribute to asthma maternal
smoking during pregnancy is a well known, and avoidable, risk.
During
pregnancy nicotine can affect a developing foetus’ lungs, predisposing the
infant to childhood asthma. Researchers from Harbor-UCLA Medical Centre,
California, tested the effect of nicotine exposure during pregnancy on rats,
looking not only at their pups (F1) but also at second generation pups (F2).
Exposure
inside the uterus resulted in both male and female (F1) offspring having
reduced lung function consistent with asthma. It also impaired lung function of
their own offspring (F2), even though the F1 rats were not themselves exposed
to nicotine once they were born. Levels of proteins increased by maternal
smoking in the lungs of their offspring such as fibronectin, collagen and
nicotinic aceylcholine receptors, were also found to be raised in the
grandchildren. Similarly the expression of PPARγ, a normal lung development,
was reduced in first and second generation offspring.
Nicotine on DNA
Dr
Virender Rehan, who led this study commented, “When we looked at the effect of
nicotine on DNA in the testes or ovaries of the rats they found that nicotine
increased the level of methylation in the testes but reduced it in the ovaries.
Nicotine also altered methylation of histones in a sex-dependent manner. These
epigenetic marks may be the mechanism behind how nicotine-induced asthma is
transmitted from one generation to the next.”
Treating
the mothers with a synthetic version of PPARγ, known to normalise lung function in nictotine exposed
offspring also prevented lung damage to F2 offspring and restored normal
histone modification patterns in their lungs.
The
effects of smoking during pregnancy are, it seems, very long lasting.
Stop
smoking education and intervention aimed at mothers-to-be and women planning
pregnancy needs to take into account the fact that nicotine itself contains
dangers to their children and their children’s children.
###
The
above story is reprinted from the October 26, 2012 news release by BioMed
Central Limited,
The
research has been published in BioMed Central’s open access journal BMC
Medicine:
Virender
K Rehan, Jie Liu, Erum Naeem, Jia Tian, Reiko Sakurai, Kenny Kwong, Omid Akbari
and John S Torday. Perinatal nicotine
exposure induces asthma in second generation offspring. BMC Medicine, 2012, 10:129
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