Applying bioethical principles to human biomonitoring

The ethical aspects of exposome research: a systematic review

In recent years, exposome research has been put forward as the next frontier for the study of human health and disease. Exposome research entails the analysis of the totality of environmental exposures and their corresponding biological responses within the human body. Increasingly, this is operationalized by big-data approaches to map the effects of internal as well as external exposures using smart sensors and multiomics technologies. However, the ethical implications of exposome research are still only rarely discussed in the literature. Therefore, we conducted a systematic review of the academic literature regarding both the exposome and underlying research fields and approaches, to map the ethical aspects that are relevant to exposome research. We identify five ethical themes that are prominent in ethics discussions: the goals of exposome research, its standards, its tools, how it relates to study participants, and the consequences of its products. Furthermore, we provide a number of general principles for how future ethics research can best make use of our comprehensive overview of the ethical aspects of exposome research. Lastly, we highlight three aspects of exposome research that are most in need of ethical reflection: the actionability of its findings, the epidemiological or clinical norms applicable to exposome research, and the meaning and action-implications of bias.

Fluorene-Chloroquine Hybrids: Synthesis, in vitro Antiplasmodial Activity, and Inhibition of Heme Detoxification Machinery of Plasmodium falciparum

Fluorene-chloroquine hybrids have been identified as a new promising class of antiplasmodial agents. The most active compound 9d exhibited good in vitro antiplasmodial activity against a chloroquine-sensitive NF54 strain of the human malaria parasite Plasmodium falciparum with an IC50 value of 139 nM. UV-visible absorption, FTIR spectral and 1H NMR titration data corroborated the binding of 9d to monomeric and µ-oxodimeric heme as well as inhibition of β-hematin formation, which collectively supported the inhibition of heme detoxification machinery in P. falciparum. In silico docking studies revealed the binding interactions of the hybrids in the active site of the wild type as well as quadruple mutant of Pf-DHFR-TS dihydrofolate enzyme. Further, the ADMET parameters were predicted and were in good agreement with the expected values, suggesting the drug likeness of the synthesized hybrid molecules.Introduction.

Pooled biological specimens for human biomonitoring of environmental chemicals: opportunities and limitations

Biomonitoring has become the "gold standard" in assessing chemical exposures, and has an important role in risk assessment. The pooling of biological specimens-combining multiple individual specimens into a single sample-can be used in biomonitoring studies to monitor levels of exposure and identify exposure trends or to identify susceptible populations in a cost-effective manner. Pooled samples provide an estimate of central tendency and may also reveal information about variation within the population. The development of a pooling strategy requires careful consideration of the type and number of samples collected, the number of pools required and the number of specimens to combine per pool in order to maximise the type and robustness of the data. Creative pooling strategies can be used to explore exposure-outcome associations, and extrapolation from other larger studies can be useful in identifying elevated exposures in specific individuals. The use of pooled specimens is advantageous as it saves significantly on analytical costs, may reduce the time and resources required for recruitment and, in certain circumstances, allows quantification of samples approaching the limit of detection. In addition, the use of pooled samples can provide population estimates while avoiding ethical difficulties that may be associated with reporting individual results.

Measuring personal chemical exposures through biomonitoring: the experiences of research participants

Using a technique called human biomonitoring, scientists can now measure hundreds of environmental chemicals and/or their metabolites in human body fluids and tissues. In this article, I examine the experiences of 28 women who participated in two different types of biomonitoring studies and received personal exposure results. I show that although the women's experiences of biomonitoring differed and were shaped by the contexts in which biomonitoring occurred, there were also remarkable similarities across contexts. Most notably, through the receipt of personal biomonitoring data, all of the women came to view themselves as partially, if not entirely, responsible for their chemical exposures (past, present, and future). These are novel findings, which suggest that as scientists increasingly measure individuals' exposures to environmental chemicals found in common consumer products and food, the distinctions between environmental and lifestyle risks are being blurred; that is, environmental risks are increasingly experienced as lifestyle risks.

Advancing human health risk assessment: integrating recent advisory committee recommendations

Over the last dozen years, many national and international expert groups have considered specific improvements to risk assessment. Many of their stated recommendations are mutually supportive, but others appear conflicting, at least in an initial assessment. This review identifies areas of consensus and difference and recommends a practical, biology-centric course forward, which includes: (1) incorporating a clear problem formulation at the outset of the assessment with a level of complexity that is appropriate for informing the relevant risk management decision; (2) using toxicokinetics and toxicodynamic information to develop Chemical Specific Adjustment Factors (CSAF); (3) using mode of action (MOA) information and an understanding of the relevant biology as the key, central organizing principle for the risk assessment; (4) integrating MOA information into dose-response assessments using existing guidelines for non-cancer and cancer assessments; (5) using a tiered, iterative approach developed by the World Health Organization/International Programme on Chemical Safety (WHO/IPCS) as a scientifically robust, fit-for-purpose approach for risk assessment of combined exposures (chemical mixtures); and (6) applying all of this knowledge to enable interpretation of human biomonitoring data in a risk context. While scientifically based defaults will remain important and useful when data on CSAF or MOA to refine an assessment are absent or insufficient, assessments should always strive to use these data. The use of available 21st century knowledge of biological processes, clinical findings, chemical interactions, and dose-response at the molecular, cellular, organ and organism levels will minimize the need for extrapolation and reliance on default approaches.

Applying bioethical principles to place-based communities and cultural group protections: the case of biomonitoring results communication

In this article, an argument is made for extending bioethical principles to place-based community and cultural group protections when there are conflicting perspectives on reporting individual results of biomonitoring studies. Bioethical principles of beneficence, nonmaleficence, respect for autonomy, and justice can incorporate participatory decision-making and understandings of the group conditions of individual research participants, particularly for research studies with vulnerable groups. Arguments for and against biomonitoring communication to individual participants are reviewed here. Assessments of risks and benefits of biomonitoring communication can be improved by considering the contextual conditions of cultural groups and place-based communities. Providing participatory decision-making with all stakeholders about biomonitoring communication can provide more fair benefits than adopting a general, prescriptive clinical standard that favors only group report-backs when clinical utility is low and the scientific understandings of low dose exposures of chemical contaminants to humans are still uncertain.

Subjects agree to participate in environmental health studies without fully comprehending the associated risk

Recent advances in environmental health research have greatly improved our ability to measure and quantify how individuals are exposed. These advances, however, bring bioethical uncertainties and potential risks that individuals should be aware of before consenting to participate. This study assessed how well participants from two environmental health studies comprehended consent form material. After signing the consent form, participants were asked to complete a comprehension assessment tool. The tool measured whether participants could recognize or recall six elements of the consent form they had just reviewed. Additional data were collected to look for differences in comprehension by gender, age, race, and the time spent reading the original consent form. Seventy-three participants completed a comprehension assessment tool. Scores ranged from 1.91 to 6.00 (mean = 4.66); only three people had perfect comprehension scores. Among the least comprehended material were questions on study-related risks. Overall, 53% of participants were not aware of two or more study-related risks. As environmental public health studies pose uncertainties and potential risks, researchers need to do more to assess participants’ understanding before assuming that individuals have given their ‘informed’ consent.

Methemoglobinemia caused by 8-aminoquinoline drugs: DFT calculations suggest an analogy to H4B's role in nitric oxide synthase

We suggest a possible mechanism of how 8-aminoquinolines (8-AQ's) cause hemotoxicity by oxidizing hemoglobin to methemoglobin. In our DFT calculations, we found that 5-hydroxyprimaquine is able to donate an electron to O(2) to facilitate its conversion to H(2)O(2). Meanwhile, Fe(II) is oxidized to Fe(III) and methemoglobin is formed. In this mechanism, the 8-AQ drug plays a similar role as that of H(4)B in nitric oxide synthase. Furthermore, our study offers an approach to inform the design of less toxic antimalarial drugs.