Early programming and environmental epigenetics of asthma.

The term "early programming" describes the mechanisms by which specific environmental exposures during critical periods of early development have a long-term impact on a child's disease risks in later life. Moreover, this effect is passed on across generations even after discontinuation of the exposure. Understanding these mechanisms offers the potential of targeted therapeutic reprogramming in order to prevent asthma. Programming of diseases is caused by epigenetic mechanisms. These are heritable gene modifications that leave the DNA sequence untouched but can nonetheless be transferred to the next generation. The influence of prenatal exposures during pregnancy, such as nutrition, immune stimulatory substances or tobacco smoke on a child's risk for asthma has been highlighted in epidemiologic studies. Only recently, it was shown for the first time that exposure to nutrients or exhaust fumes in utero leads to epigenetic changes and is directly associated with asthma risk in children. This risk was transmitted across two generations. The potential of this new insight into epigenetically mediated early programming of asthma offers novel opportunities for the development of pre-symptomatic preventive strategies