Dear Colleagues,

To prevent the toxicity of chemicals, ideally we should minimize our exposure. The best case scenario, of course, is to have no exposure at all, but, in the real world, this is not possible. Are we then just ‘sitting ducks’ for toxic chemicals in the environment to damage our bodies at will? No, we are much better prepared than we thought. Living organisms appear to be more flexible than we imagined and our cells have the ability to adapt to the presence of a poison. Perhaps, a little bit of bad might be good for you. This can be exemplified with the poison acrolein, a model compound used in the toxicological research of organ damage, especially that of the lung. Acrolein is present in the environment mainly through its use in the chemical industry and the incomplete combustion of fuel. Moreover, acrolein is a component of cigarette smoke.

Lung cells exposed to a low dose of acrolein are not damaged. On the contrary, the cells adapt and their protection against the poison is upgraded (Sthijns et al. 2014). In toxicology, the notion that cells are flexible and can adapt has already existed for quite some time. This phenomenon is known as “hormesis”. It appeared that acrolein activates a sensor within the cell prompting the production of more natural antioxidant. In this way, the cells become resistant to doses that were clearly toxic before this adaptation process happened. The results obtained with acrolein demonstrate that this theoretical concept works in practice.

The pitfall is that hormesis should not be misinterpreted as carte blanche to take your daily dose of a poison to improve health; this would be unwise. The challenge is to somehow encourage hormetic adaptation to a toxic compound by another compound. The process that exposure to one compound results in hormetic adaptation to another compound we coin as transhormesis.

A wealth of data underpins the dynamics of cellular protection towards toxic compounds although this cellular flexibility has not yet been acknowledged in risk assessment procedures. Nevertheless, hormesis and transhormesis do influence how toxic a poison might be to us. Indeed, although the cells in our bodies must be ready to protect us at all times it makes no sense to wear a “suit of armour” 24 hours a day when there is no imminent threat. However, the research highlights how our body “senses” chemical threats so that we raise our defensive “shields” in time to protect us. Thus, in this way, our cells become stronger by exposure to a “little bit of bad”.

You are invited to submit manuscripts on "Hormesis and Transhormesis in Toxicology and Risk Assessment" to a special issue of International Journal of Molecular Sciences section "Molecular Toxicology. Manucripts can be submitted online at www.mdpi.com by registering and logging in on this website.

http://www.mdpi.com/journal/ijms/special_issues/hormesis_transhormesis

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