Environmental toxin biomarkers

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What impact do environmental contaminants have on human health? Until recently, it was difficult to adequately address this complex question. From animal models and cell and tissue culture studies, it has been clear for quite some time that contaminants ranging from heavy metals to organic chemicals like BPA, PCBs and dioxins can be extremely detrimental when critical thresholds are reached. Then, molecular biology studies began to demonstrate the myriad effects that these chemicals can cause at a cellular level. It is now becoming clear that even at levels once presumed to be safe, these chemicals can affect human health (e.g. by contributing to cardiovascular damage, sexual dysfunction and cancer), particularly with continued exposure. Sadly, we still don’t know exactly how much exposure is “too much” or what effect chronic low-dose exposure may have.

Unfortunately, these contaminants are present in some regions at levels that could be detrimental to human health, particularly when exposure occurs over months or even years. Since these chemicals aren’t going away anytime soon, it is important to identify biomarkers that can help determine if someone has been exposed to dangerous levels and what effects such exposure might be having.  Fortunately, recent advances in molecular biology may now make it possible for scientists to begin addressing these issues. Liquid biopsies allow for noninvasive sampling of exposed individuals.  For example, a recent study by Wallin et al. used a multi-biomarker analysis in urine to determine exposure to mycotoxin, a toxin produced by molds that can contaminate a number of different types of foods (1).

For future biomarker discovery in toxicology research, gene expression studies with RNAseq  (also known as whole-transcriptome shotgun sequencing, or WTSS) or targeted gene expression panels using RT-PCR could potentially identify changes to molecular profiles that are indicative of overexposure to specific chemicals or even identify the onset of damage to a particular tissue. What potential do you see for these technologies in toxicology biomarker research?

Reference

1. Wallin, S. et al. (2015) Biomonitoring of concurrent mycotoxin exposure among adults in Sweden through urinary multi-biomarker analysis. Food Chem. Toxicol. Epublished ahead of print.

Jim Keller

Jim Keller is a Content Development Scientist at QIAGEN. He received his PhD from the University of North Carolina – Charlotte in 2008, studying how the effects of the environmental toxicant TCDD on bone and tooth development differ based on genetic factors. He is currently interested in how genetic, epigenetic, and environmental factors affect gene expression.

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