A circular toxicity approach to isoprostanes: From markers of oxidative stress, to epidemiological warning systems and agents of aquatic toxicity


Isoprostanes (IsoPs) are a class of oxidation products naturally formed in vivo that are indicative of endogenous oxidative stress. In individuals with chronic and oxidative stress related diseases, IsoPs are increased to pathological levels. Since they are excreted through urine into sewage systems, IsoPs can be detected in wastewater treatment plants' (WWTPs) effluents and thus can be used to evaluate the health status of a given population. The underlying principle is that higher isoprostanes WWTPs' levels correspond to populations undergoing higher levels of oxidative stress, and thus disease. However, IsoPs are not eliminated by WWTPs and will end up being released into the aquatic environment, where they will be available for uptake by aquatic species. Being bioactive molecules, it has been suggested that IsoPs in the environment may elicit oxidative stress in aquatic organisms. In this context, we have critically reviewed the available data on IsoPs as products and effectors of toxicity, and propose the new concept of "circular toxicity". In general, IsoPs excreted by humans as a consequence of oxidative stress are released into the aquatic environment where they may interact with aquatic organisms and induce the production of more IsoPs. These stress markers, in turn, will also be excreted, increasing the already high levels of stressors in the aquatic environment and thus create an escalating cycle of oxidative stress. (C) 2018 Elsevier Ltd. All rights reserved.



subject category

Environmental Sciences & Ecology


Pais, RT; Sousa, ACA; Pastorinho, MR

our authors


This work was financially supported by FEDER funds through the POCI - COMPETE 2020 -Operational Programme Competitiveness and Internationalisation in Axis I - Strengthening research, technological development and innovation (Project POCI-01-0145-FEDER-007491) and Portuguese National Funds by FCT -Foundation for Science and Technology (Project UID/Multi/00709/2013 and project UID/CTM/50011/2013). Further financial support was provided by "Interdisciplinary Challenges on Neurodegeneration (ICON)" (Ref. CENTRO-01-0145-FEDER-000013). Ana C.A. Sousa also acknowledges the financial support of Labex DRIIHM (PIA), via OHMI Estarreja - OHM Bassin Minier de Provence, International Observatory Hommes-Millieux, tool of CNRS/INEE -National Center for Scientific Research/Institute of Ecology and Environment, France.

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