Sensitive monitoring of the main metabolites of tri-(2-ethylhexyl) trimellitate (TOTM) in urine by coupling of on-line SPE, UHPLC and tandem mass spectrometry

Assessment of the plasticizer exposure of hospital workers regularly handling medical devices: A pilot study

Plastic medical devices, e.g. infusion sets, blood bags or tubing material, that are used manifold in the medical treatment of hospital patients, usually contain considerable amounts of plasticizers. Whereas several studies showed highly elevated inner plasticizer levels of patients treated with plasticized medical devices, little is known about the exposure situation of hospital staff. The present pilot study aimed to evaluate the urinary plasticizer metabolite levels of selected hospital workers of the blood bank (medical technical assistants, MTA) and of perfusionists that are regularly handling plasticized medical devices in order to estimate the work-related amount of the inner individual plasticizer exposure. The study subjects were asked to collect pre- and post-shift spot urine samples over the course of a working week, that were subsequently analyzed for selected urinary metabolites of the plasticizers DEHP, DINCH, DEHTP and TEHTM. Although the observed differences were rather low, a differentiated approach revealed a perceptible impact of the respective workplace environment on the individual urinary plasticizer metabolite levels. Thus, the group of blood bank MTA showed significantly elevated increment levels of urinary DEHP and DINCH metabolites, while the group of perfusionists, showed a considerable higher detection frequency of the main urinary TEHTM metabolite. All in all, however, it can be cautiously concluded by the results of the presented pilot study that a regular handling of plasticized medical devices by hospital employees (via inhalation or dermal contact) contributes demonstrably but yet only marginally to the individual internal plasticizer exposure.

Exposure to the non-phthalate plasticizer di-heptyl succinate is less disruptive to C57bl/6N mouse recovery from a myocardial infarction than DEHP, TOTM or related di-octyl succinate

Phthalate plasticizers are incorporated into plastics to make them soft and malleable, but are known to leach out of the final product into their surroundings with potential detrimental effects to human and ecological health. The replacement of widely-used phthalate plasticizers, such as di-ethylhexyl phthalate (DEHP), that are of known toxicity, by the commercially-available alternative Tris(2-ethylhexyl) tri-mellitate (TOTM) is increasing. Additionally, several newly designed "green" plasticizers, including di-heptyl succinate (DHPS) and di-octyl succinate (DOS) have been identified as potential replacements. However, the impact of plasticizer exposure from medical devices on patient recovery is unknown and, moreover, the safety of TOTM, DHPS, and DOS is not well established in the context of patient recovery. To study the direct effect of clinically based chemical exposures, we exposed C57bl/6 N male and female mice to DEHP, TOTM, DOS, and DHPS during recovery from cardiac surgery and assessed survival, cardiac structure and function, immune cell infiltration into the cardiac wound and activation of the NLRP3 inflammasome. Male, but not female, mice treated in vivo with DEHP and TOTM had greater cardiac dilation, reduced cardiac function, increased infiltration of neutrophils, monocytes, and macrophages and increased expression of inflammasome receptors and effectors, thereby suggesting impaired recovery in exposed mice. In contrast, no impact was detected in female mice and male mice exposed to DOS and DHPS. To examine the direct effects in cells involved in wound healing, we treated human THP-1 macrophages with the plasticizers in vitro and found DEHP induced greater NLRP3 expression and activation. These results suggest that replacing current plasticizers with non-phthalate-based plasticizers may improve patient recovery, especially in the male population. In our assessment, DHPS is a promising possibility for a non-toxic biocompatible plasticizer.

Medical devices used in NICU: The main source of plasticisers' exposure of newborns

Phthalates and other plasticisers are extensively used in medical devices (MD) from which they can leach out and lead to potential multiple problems for the patients. This exposure is a major issue because it is associated with reproductive and neurodevelopment disorders. The Neonatal Intensive Care Units (NICU) population is at high risk due to the daily intensive medical interventions, the reduced ability of newborns to remove these contaminants and their higher sensitivity to endocrine disruptors. We conducted a multicentric biomonitoring study to assess and compare the urinary levels of DEHP (di-(2-ethylhexyl)phthalate), DEHTP (di-(2-ethylhexyl)terephthalate) and TEHTM (tri-(2-ethylhexyl)trimellitate) metabolites as biomarkers of this exposure during and after the newborns' stay in NICU. Daily urinary samples were collected in NICU and at discharge from the hospital for each patient. MD sources and exposure factors were also investigated. 508 urinary samples from 97 patients enrolled in centres 1 and 2 (C1/C2) were collected. The exposure of newborns to DEHP was greater than that of DEHTP and TEHTM, with a median concentration of DEHP metabolites (C1:195.63 ng/mL;C2:450.87 ng/mL) respectively 5 to 10 times higher and 57 to 228 times higher than the median concentrations of DEHTP and TEHTM metabolites. The urinary concentrations of DEHP and TEHTM metabolites were significantly lower at discharge than in NICU, with a 18-and 35-fold decrease for DEHP and a 4 and 8-fold decrease for TEHTM, respectively for C1 and C2, but were similar for DEHTP metabolites. MD used for respiratory assistance, infusion therapy,enteral nutrition and transfusion were the main sources of exposure. Smaller gestational age and body weight significantly increased the newborns' exposure. The elevated levels of DEHP metabolites in NICU patients are still alarming. Additional efforts are necessary to promote its substitution in MD by possibly safer alternatives such as TEHTM and DEHTP, particularly when used for the care of newborns.

Simultaneous and sensitive determination of the main metabolites of the plasticizer DEHP and its substitutes DEHTP, DINCH and TEHTM in human urine by coupling of on-line SPE, UHPLC and tandem mass spectrometry

With the prominent but toxicologically critical plasticizer di-(2-ethylhexyl) phthalate (DEHP) declining, alternative plasticizers are increasingly used leading to a continuously more diverse exposure situation of humans with multiple plasticizers. Therefore, an on-line SPE-LC-MS/MS method for the simultaneous determination of the most relevant urinary biomarkers of exposure to DEHP and the alternative plasticizers 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH), di-(2-ethylhexyl) terephthalate (DEHTP) and tri-(2-ethylhexyl) trimellitate (TEHTM) was developed. The method is characterized by a high sensitivity with limits of detection ranging from 0.006 to 0.047 μg L^-1 combined with an easy and straightforward sample preparation procedure. The wide linear working range of the method enables a reliable determination of analyte background levels in the general population as well as its potential use for monitoring studies investigating elevated plasticizer exposure settings. The method was successfully applied to urine samples from ten volunteers without occupational exposure to plasticizers revealing ubiquitous background exposure levels of the common plasticizers DEHP, DEHTP and DINCH.

In vitro and in silico approach to study the hormonal activities of the alternative plasticizer tri-(2-ethylhexyl) trimellitate TEHTM and its metabolites

Tri-(2-ethylhexyl) trimellitate (TEHTM) is a plasticizer for polyvinyl chloride (PVC) material used in medical devices. It is an alternative to di-(2-ethylhexyl) phthalate (DEHP), a well-known reprotoxic and endocrine disruptor. As plasticizers are known to easily migrate when in contact with fatty biological fluids, patient exposure to TEHTM is highly probable. However, there is currently no data on the potential endocrine-disrupting effects of its human metabolites. To evaluate the effects of TEHTM metabolites on endocrine activity, they were first synthesized and their effects on estrogen, androgen and thyroid receptors, as well as steroid synthesis, were investigated by combining in vitro and in silico approaches. Among the primary metabolites, only 4-MEHTM (4-mono-(2-ethylhexyl) trimellitate) showed agonist activities on ERs and TRs, while three diesters were TR antagonists at non-cytotoxic concentrations. These results were completed by docking experiments which specified the ER and TR isoforms involved. A mixture of 2/1-MEHTM significantly increased the estradiol level and reduced the testosterone level in H295R cell culture supernatants. The oxidized secondary metabolites of TEHTM had no effect on ER, AR, TR receptors or on steroid hormone synthesis. Among the fourteen metabolites, these data showed that two of them (4-MEHTM and 2/1-MEHTM) induced effect on hormonal activities in vitro. However, by comparing the concentrations of the primary metabolites found in human urine with the active concentrations determined in bioassays, it can be suggested that the metabolites will not be active with regard to estrogen, androgen, thyroid receptors and steroidogenesis-mediated effects.

Substitutes mimic the exposure behaviour of REACH regulated phthalates - A review of the German HBM system on the example of plasticizers

The population is constantly exposed to potentially harmful substances present in the environment, including inter alia food and drinking water, consumer products, and indoor air. Human biomonitoring (HBM) is a valuable tool to determine the integral, internal exposure of the general population, including vulnerable subgroups, to provide the basis for risk assessment and policy advice. The German HBM system comprises of five pillars: (1) the development of suitable analytical methods for new substances of concern, (2) cross-sectional population-representative German Environmental Surveys (GerES), (3) time trend analyses using archived samples from the Environmental Specimen Bank (ESB), (4) the derivation of health-based guidance values as a risk assessment tool, and (5) transfer of data into the European cooperation network HBM4EU. The goal of this paper is to present the complementary elements of the German HBM system and to show its strengths and limitations on the example of plasticizers. Plasticizers have been identified by EU services and HBM4EU partners as priority substances for chemical policy at EU level. Using the complementary elements of the German HBM system, the internal exposure to classical phthalates and novel alternative plasticizers can be reliably monitored. It is shown that market changes, due to regulation of certain phthalates and the rise of substitutes, are rapidly reflected in the internal exposure of the population. It was shown that exposure to DEHP, DiBP, DnBP, and BBzP decreased considerably, whereas exposure to the novel substitutes such as DPHP, DEHTP, and Hexamoll®DINCH has increased significantly. While health-based guidance values for several phthalates (esp. DnBP, DiBP, DEHP) were exceeded quite often at the turn of the millennium, exceedances today have become rarer. Still, also the latest GerES reveals the ubiquitous and concurrent exposures to many plasticizers. Of concern is that the youngest children showed the highest exposures to most of the investigated plasticizers and in some cases their levels of DiBP and DnBP still exceeded health-based guidance values. Over the last years, mixture exposures are increasingly recognized as relevant, especially if the toxicological modes of action are similar. This is supported by a cumulative risk assessment for four endocrine active phthalates which confirms the still concerning cumulative exposure in many young children. Given the adverse health effects of some phthalates and the limited toxicological knowledge of substitutes, exposure reduction and surveillance are needed on German and EU-level. Substitutes need to be monitored, to intervene if exposures are threatening to exceed acceptable levels, or if new toxicological data question their appropriateness. It is strongly recommended to reconsider the use of plastics and plasticizers.