Approaches to mixture risk assessment of PFASs in the European population based on human hazard and biomonitoring data

Per- and polyfluoroalkyl substances (PFASs) are a highly persistent, mobile, and bioaccumulative class of chemicals, of which emissions into the environment result in long-lasting contamination with high probability for causing adverse effects to human health and the environment. Within the European Biomonitoring Initiative HBM4EU, samples and data were collected in a harmonized way from human biomonitoring (HBM) studies in Europe to derive current exposure data across a geographic spread. We performed mixture risk assessments based on recent internal exposure data of PFASs in European teenagers generated in the HBM4EU Aligned Studies (dataset with N = 1957, sampling years 2014-2021). Mixture risk assessments were performed based on three hazard-based approaches: the Hazard Index (HI) approach, the sum value approach as used by the European Food Safety Authority (EFSA) and the Relative Potency Factor (RPF) approach. The HI approach resulted in the highest risk estimates, followed by the RPF approach and the sum value approach. The assessments indicate that PFAS exposure may result in a health risk in a considerable fraction of individuals in the HBM4EU teenager study sample, thereby confirming the conclusion drawn in the recent EFSA scientific opinion. This study underlines that HBM data are of added value in assessing the health risks of aggregate and cumulative exposure to PFASs, as such data are able to reflect exposure from different sources and via different routes.This work was supported by the European Union’s Horizon 2020 research and innovation programme under Grant agreement No 733032 HBM4EU (www.HBM4EU.eu), and received co-funding from the au thors’ organizations. The Norwegian Institute of Public Health (NIPH) has contributed to funding of the Norwegian Environmental Biobank (NEB), and the laboratory measurements have partly been funded by the Research Council of Norway through research projects (275903 and 268465). The PCB cohort (follow-up) received additional funding from the Ministry of Health of the Slovak Republic (program 07B0103).S

PFAS levels and determinants of variability in exposure in European teenagers - Results from the HBM4EU aligned studies (2014-2021)

Background: Perfluoroalkyl substances (PFAS) are man-made fluorinated chemicals, widely used in various types of consumer products, resulting in their omnipresence in human populations. The aim of this study was to describe current PFAS levels in European teenagers and to investigate the determinants of serum/plasma concentrations in this specific age group. Methods: PFAS concentrations were determined in serum or plasma samples from 1957 teenagers (12-18 years) from 9 European countries as part of the HBM4EU aligned studies (2014-2021). Questionnaire data were post-harmonized by each study and quality checked centrally. Only PFAS with an overall quantification frequency of at least 60% (PFOS, PFOA, PFHxS and PFNA) were included in the analyses. Sociodemographic and lifestyle factors were analysed together with food consumption frequencies to identify determinants of PFAS exposure. The variables study, sex and the highest educational level of household were included as fixed factors in the multivariable linear regression models for all PFAS and each dietary variable was added to the fixed model one by one and for each PFAS separately. Results: The European exposure values for PFAS were reported as geometric means with 95% confidence intervals (CI): PFOS [2.13 μg/L (1.63-2.78)], PFOA ([0.97 μg/L (0.75-1.26)]), PFNA [0.30 μg/L (0.19-0.45)] and PFHxS [0.41 μg/L (0.33-0.52)]. The estimated geometric mean exposure levels were significantly higher in the North and West versus the South and East of Europe. Boys had significantly higher concentrations of the four PFAS compared to girls and significantly higher PFASs concentrations were found in teenagers from households with a higher education level. Consumption of seafood and fish at least 2 times per week was significantly associated with 21% (95% CI: 12-31%) increase in PFOS concentrations and 20% (95% CI: 10-31%) increase in PFNA concentrations as compared to less frequent consumption of seafood and fish. The same trend was observed for PFOA and PFHxS but not statistically significant. Consumption of eggs at least 2 times per week was associated with 11% (95% CI: 2-22%) and 14% (95% CI: 2-27%) increase in PFOS and PFNA concentrations, respectively, as compared to less frequent consumption of eggs. Significantly higher PFOS concentrations were observed for participants consuming offal (14% (95% CI: 3-26%)), the same trend was observed for the other PFAS but not statistically significant. Local food consumption at least 2 times per week was associated with 40% (95% CI: 19-64%) increase in PFOS levels as compared to those consuming local food less frequently. Conclusion: This work provides information about current levels of PFAS in European teenagers and potential dietary sources of exposure to PFAS in European teenagers. These results can be of use for targeted monitoring of PFAS in food.This work was supported by the European Union’s Horizon 2020 research and innovation programme under Grant agreement No 733032 HBM4EU (www.HBM4EU.eu), and received co-funding from the authors’ organizations: Riksmaten Adolescents: Riksmaten Adolescents was performed by the Swedish Food Agency with financial support from the Swedish Environmental Protection Agency and the Swedish Civil Contingencies Agency. NEB II: The Norwegian Institute of Public Health (NIPH) has contributed to funding of the Norwegian Environmental Biobank (NEB). The laboratory measurements have partly been funded by the Research Council of Norway through research projects (275903 and 268465) PCB cohort follow-up: PCB cohort follow-up received additional funding from the Ministry of Health of the Slovak Republic, program 07B0103. BEA: BEA study was funded by the Spanish Ministry of Agriculture, Fisheries and Food and the Instituto de Salud Carlos III (SEG 1321/15) SLO-CRP: The Slovenian SLO-CRP study was co-financed by the Jozef Stefan Institute program P1- 0143, and a national project “Exposure of children and adolescents to selected chemicals through their habitat environment” (grant agreement No. C2715-16-634802). CROME: CROME study was co-funded by the European Commission research funds of Horizon 2020. ESTEBAN: ESTEBAN study was funded by Santé Publique France and the French ministries of Health and the Environment. GerES V-sub: The funding of the German Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection is gratefully acknowledged. FLEHS IV: The Flemish Center of Expertise on Environment and Health is funded by the Government of Flanders, Department of Environment & Spatial Development.S

A round robin approach to the analysis of bisphenol a (BPA) in human blood samples

BACKGROUND: Human exposure to bisphenol A (BPA) is ubiquitous, yet there are concerns about whether BPA can be measured in human blood. This Round Robin was designed to address this concern through three goals: 1) to identify collection materials, reagents and detection apparatuses that do not contribute BPA to serum; 2) to identify sensitive and precise methods to accurately measure unconjugated BPA (uBPA) and BPA-glucuronide (BPA-G), a metabolite, in serum; and 3) to evaluate whether inadvertent hydrolysis of BPA-G occurs during sample handling and processing. METHODS: Four laboratories participated in this Round Robin. Laboratories screened materials to identify BPA contamination in collection and analysis materials. Serum was spiked with concentrations of uBPA and/or BPA-G ranging from 0.09-19.5 (uBPA) and 0.5-32 (BPA-G) ng/mL. Additional samples were preserved unspiked as ‘environmental’ samples. Blinded samples were provided to laboratories that used LC/MSMS to simultaneously quantify uBPA and BPA-G. To determine whether inadvertent hydrolysis of BPA metabolites occurred, samples spiked with only BPA-G were analyzed for the presence of uBPA. Finally, three laboratories compared direct and indirect methods of quantifying BPA-G. RESULTS: We identified collection materials and reagents that did not introduce BPA contamination. In the blinded spiked sample analysis, all laboratories were able to distinguish low from high values of uBPA and BPA-G, for the whole spiked sample range and for those samples spiked with the three lowest concentrations (0.5-3.1 ng/ml). By completion of the Round Robin, three laboratories had verified methods for the analysis of uBPA and two verified for the analysis of BPA-G (verification determined by: 4 of 5 samples within 20% of spiked concentrations). In the analysis of BPA-G only spiked samples, all laboratories reported BPA-G was the majority of BPA detected (92.2 – 100%). Finally, laboratories were more likely to be verified using direct methods than indirect ones using enzymatic hydrolysis. CONCLUSIONS: Sensitive and accurate methods for the direct quantification of uBPA and BPA-G were developed in multiple laboratories and can be used for the analysis of human serum samples. BPA contamination can be controlled during sample collection and inadvertent hydrolysis of BPA conjugates can be avoided during sample handling

Serum Biomarkers of Myocardial Remodeling and Coronary Dysfunction in Early Stages of Hypertrophic Cardiomyopathy in the Young

Hypertrophic cardiomyopathy (HCM) remains the leading cause of sudden cardiac death in the young. Early markers for HCM are important to identify individuals at risk. The aim of this study was to investigate novel serum biomarkers reflecting myocardial remodeling, microfibrosis, and vascular endotheliopathy in the early stages of familial HCM in young patients. Twenty-three HCM patients, 16 HCM-risk individuals, and 66 controls (median 15 years) underwent echocardiography and serum analysis for cathepsin S, endostatin, myostatin, type I collagen degradation marker (ICTP), matrix metalloproteinase (MMP)-9, vascular endothelial growth factor receptor (VEGFR)-1, and vascular and intercellular adhesion molecules (VCAM, ICAM). In a subset of the population, global myocardial perfusion was performed by magnetic resonance imaging. Cathepsin S (p = 0.0009), endostatin (p amp;lt; 0.0001), MMP-9 (p = 0.008), and VCAM (p = 0.04) were increased in the HCM group and correlated to left ventricular mass index and mitral E/e (p amp;lt; 0.01). In the HCM-risk group, myostatin was decreased (p = 0.004), whereas ICAM was increased (p = 0.002). Global perfusion was decreased in the HCM group (p amp;lt; 0.05) versus controls. Endostatin and mitral E/e correlated inversely to myocardial perfusion (p aeamp;lt;currencyamp;gt; 0.05). This is the first study demonstrating adverse changes in biomarkers reflecting myocardial matrix remodeling, microfibrosis, and vascular endotheliopathy in early stage of hypertrophic cardiomyopathy in the young

Diverging temporal trends of human exposure to bisphenols and plastizisers, such as phthalates, caused by substitution of legacy EDCs?

Phthalates and phenolic substances were investigated in urine samples from first-time mothers in Uppsala, Sweden, collected between 2009 and 2014. These substances have a comparably fast metabolism and urinary metabolites are predominantly analysed. The main aim was to investigate if measures to decrease production and use of certain phthalates and bisphenol A (BPA) have resulted in decreased human exposure, and to determine if exposures to replacement chemicals have increased. Temporal trends were evaluated for metabolites (n=13) of seven phthalates, a phthalate replacer, four different bisphenols, triclosan, one organophosphate-based flame retardant, and for two pesticides. The results showed downward trends of several phthalates which are in the process of being regulated and phased out. Concomitantly, an increasing trend was seen for a metabolite of the phthalate replacer Di-iso-nonylcyclohexane 1,2-dicarboxylate (DiNCH). Bisphenol A (BPA) showed a downward trend, whereas bisphenol F, identified as one of the substitutes for BPA, showed an increasing trend. The decreasing trend of triclosan is likely due to declining use within the EU. Temporal trend studies of urine samples make it possible to investigate human exposure to rapidly metabolised substances and study how measures taken to regulate and replace problematic chemicals affect human exposure

NADPH Oxidase-2: Linking Glucose, Acidosis, and Excitotoxicity in Stroke

Significance: Neuronal superoxide production contributes to cell death in both glutamate excitotoxicity and brain ischemia (stroke). NADPH oxidase-2 (NOX2) is the major source of neuronal superoxide production in these settings, and regulation of NOX2 activity can thereby influence outcome in stroke. Recent Advances: Reduced NOX2 activity can rescue cells from oxidative stress and cell death that otherwise occur in excitotoxicity and ischemia. NOX2 activity is regulated by several factors previously shown to affect outcome in stroke, including glucose availability, intracellular pH, protein kinase ζ/δ, casein kinase 2, phosphoinositide-3-kinase, Rac1/2, and phospholipase A2. The newly identified functions of these factors as regulators of NOX2 activity suggest alternative mechanisms for their effects on ischemic brain injury. Critical Issues: Key aspects of these regulatory influences remain unresolved, including the mechanisms by which rac1 and phospholipase activities are coupled to N-methyl-D-aspartate (NMDA) receptors, and whether superoxide production by NOX2 triggers subsequent superoxide production by mitochondria. Future Directions: It will be important to establish whether interventions targeting the signaling pathways linking NMDA receptors to NOX2 in brain ischemia can provide a greater neuroprotective efficacy or a longer time window to treatment than provided by NMDA receptor blockade alone. It will likewise be important to determine whether dissociating superoxide production from the other signaling events initiated by NMDA receptors can mitigate the deleterious effects of NMDA receptor blockade. Antioxid. Redox Signal. 22, 161–174