Biomarkers of mercury toxicity: Past, present, and future trends

ABSTRACT

Mercury (Hg) toxicity continues to represent a global health concern. Given that human populations are mostly exposed to low chronic levels of mercurial compounds (methylmercury through fish, mercury vapor from dental amalgams, and ethylmercury from vaccines), the need for more sensitive and refined tools to assess the effects and/or susceptibility to adverse metal-mediated health risks remains. Traditional biomarkers, such as hair or blood Hg levels, are practical and provide a reliable measure of exposure, but given intra-population variability, it is difficult to establish accurate cause–effect relationships. It is therefore important to identify and validate biomarkers that are predictive of early adverse effects prior to adverse health outcomes becoming irreversible. This review describes the predominant biomarkers used by toxicologists and epidemiologists to evaluate exposure, effect and susceptibility to Hg compounds, weighing on their advantages and disadvantages. Most importantly, and in light of recent findings on the molecular mechanisms underlying Hg-mediated toxicity, potential novel biomarkers that might be predictive of toxic effect are presented, and the applicability of these parameters in risk assessment is examined.

Acknowledgments

The authors thank the reviewers of this manuscript whose comments and suggestions contributed to significantly improve the original submission.

Funding

Cristina Carvalho and Vasco Branco are supported by Fundação para a Ciência e Tecnologia, Portugal (www.fct.pt) through MERTOX project (PTDC/QUI-BIQ/117281/2010) and the Post Doc fellowship (SFRH/BPD/85219/2012). The work was funded, in part, by iMed.ULisboa through project UID/DTP/04138/2013 also from FCT. MA was supported in part by grants from the NIH, R01 ES10563 and R01 ES07331, and R01 ES020852. MF was supported in part by grants from the Brazilian Agencies CNPq, CAPES and FAPESC.

Additional information

Funding

Cristina Carvalho and Vasco Branco are supported by Fundação para a Ciência e Tecnologia, Portugal (www.fct.pt) through MERTOX project (PTDC/QUI-BIQ/117281/2010) and the Post Doc fellowship (SFRH/BPD/85219/2012). The work was funded, in part, by iMed.ULisboa through project UID/DTP/04138/2013 also from FCT. MA was supported in part by grants from the NIH, R01 ES10563 and R01 ES07331, and R01 ES020852. MF was supported in part by grants from the Brazilian Agencies CNPq, CAPES and FAPESC.