Pediatric exposure and potential toxicity of phthalate plasticizers

Thyroid endocrine disruption in zebrafish larvae after exposure to mono-(2-ethylhexyl) phthalate (MEHP)

Phthalates are extensively used as plasticizers in a variety of daily-life products, resulting in widespread distribution in aquatic environments. However, limited information is available on the endocrine disrupting effects of phthalates in aquatic organisms. The aim of the present study was to examine whether exposure to mono-(2-ethylhexyl) phthalate (MEHP), the hydrolytic metabolite of di-(2-ethylhexyl) phthalate (DEHP) disrupts thyroid endocrine system in fish. In this study, zebrafish (Danio rerio) embryos were exposed to different concentrations of MEHP (1.6, 8, 40, and 200 μg/L) from 2 h post-fertilization (hpf) to 168 hpf. The whole-body content of thyroid hormone and transcription of genes involved in the hypothalamic-pituitary-thyroid (HPT) axis were examined. Treatment with MEHP significantly decreased whole-body T4 contents and increased whole-body T3 contents, indicating thyroid endocrine disruption. The upregulation of genes related to thyroid hormone metabolism (Dio2 and UGT1ab) might be responsible for decreased T4 contents. Elevated gene transcription of Dio1 was also observed in this study, which might assist to degrade increased T3 contents. Exposure to MEHP also significantly induced transcription of genes involved in thyroid development (Nkx2.1 and Pax8) and thyroid hormone synthesis (TSHβ, NIS and TG). However, the genes encoding proteins involved in TH transport (transthyretin, TTR) was transcriptionally significantly down-regulated after exposure to MEHP. Overall, these results demonstrate that acute exposure to MEHP alters whole-body contents of thyroid hormones in zebrafish embryos/larvae and changes the transcription of genes involved in the HPT axis, thus exerting thyroid endocrine toxicity.

Induction of oxidative stress and histological changes in liver by subacute doses of butyl cyclohexyl phthalate

Phthalates are esters of phthalic acid and are mainly used as plasticizers in a wide variety of products and applications. There is no information on butyl cyclohexyl phthalate (BCP) toxicity. This study was performed to evaluate the histopathological effects and to determine oxidative stress inducing potential in liver by subacute exposure of BCP. The animals of the treatment groups were orally administered 100, 200, and 400 mg/kg/day BCP for 5 consecutive days per week during 28 days. As a result, no significant changes were observed in body weight gains, and absolute and relative liver weights of liver of BCP treated mice, when compared with control group. Although the degree of lipid peroxidation in the liver tissue of all BCP exposure groups were significantly higher than those of the control (p < 0.01), SOD and CAT activities in liver tissue of mice of 200 and 400 mg/kg exposure groups were significantly lower than those of the controls (p < 0.01). Moreover, BCP caused dose-dependent histological changes in the liver of mice such as congestions in vena centralis, an enlargement of the sinusoids, degeneration in hepatocytes, vacuole formations and presence of lipid droplets in hepatocytes, eosinophilic cytoplasm. While iNOS immunoreactivity was increased in all treatment groups, Type IV collagen and Connexin 43 immunoreactivities were decreased in all treatment groups compared with the control group. Significant decrease was observed in the number of TUNEL-positive liver cells of BCP treated mice. These results suggested that BCP exposure induces oxidative stress in liver and exposure of BCP during long time period could lead to hepatocarcinogenesis.

Effects of maternal exposure to di(2-ethylhexyl)phthalate (DEHP) during pregnancy on susceptibility to neonatal asthma

Di(2-ethylhexyl) phthalate (DEHP) is used as a plasticizer and is widely dispersed in the environment. In this study, we investigated the effects of maternal exposure to DEHP during pregnancy on neonatal asthma susceptibility using a murine model of asthma induced by ovalbumin (OVA). Pregnant BALB/c mice received DEHP from gestation day 13 to lactation day 21. Their offspring were sensitized on postnatal days (PNDs) 9 and 15 by intraperitoneal injection of 0.5μg OVA with 200μg aluminum hydroxide. On PNDs 22, 23 and 24, live pups received an airway challenge of OVA for 30min. Offspring from pregnant mice that received DEHP showed reductions in inflammatory cell count, interleukin (IL)-4, IL-13, and eotaxin in their bronchoalveolar lavage fluid and in total immunoglobulin E and OVA-specific IgE in their plasma compared with offspring from pregnant mice that did not receive DEHP treatment. These results were consistent with histological analysis and immunoblotting. Maternal exposure to DEHP reduces airway inflammation and mucus production in offspring, with a decrease in inducible nitric oxide synthase (iNOS) in the lung tissue. This study suggests that maternal exposure to DEHP during pregnancy reduces asthmatic responses induced by OVA challenge in offspring. These effects were considered to be closely related to the suppression of Th2 immune responses and iNOS expression.

Neurotoxicity of dibutyl phthalate in brain development following perinatal exposure: a study in rats

Dibutyl-phthalate (DBP) is a ubiquitous environmental contaminant. However, its neurotoxic effects on neonatal, immature or mature brains remain unclear. Here, we aimed to investigate the neurotoxicity of perinatal exposure of DBP on rodent offspring animals. Pregnant rats received intragastric DBP (500mg/kg body weight) daily from gestational day (GD) 6 to postnatal day (PND) 21. Animals in the control group received the same volume of edible corn oil. Brain sections or tissues from offspring rats on PND5, PND21 and PND60 were collected for analysis. Histological examination demonstrated that perinatal exposure of DBP resulted in hippocampal neuron loss and structural alternation in neonatal and immature offspring rats (PND5 and PND21), while no significant change was found in mature rats (PND60). DBP exposure induced cell apoptosis in hippocampal neurons of these neonatal and immature animals, as evidenced by the increased number of TUNEL-positive and Annexin V-propidium iodide (PI) positive cells and up-regulated caspase-3 activity. Moreover, DBP exposure decreased the expression of synaptophysin in the hippocampus and reduced both the slope and amplitude of field excitatory postsynaptic potentials (fEPSPs). DBP also impaired the spatial learning and memory of offspring rats. However, no significant difference in the susceptibility to DBP-induced neurotoxicity was found between male and female offspring rats. Our findings indicated that perinatal exposure of DBP could induce neurotoxicity in neonatal and immature offspring animals, but had no influence on mature animals after DBP withdrawal. These results may provide basic experimental evidence for better understanding the neurotoxic effects of DBP on neonatal, immature and mature brains.

Phthalates in the NICU: is it safe?

AIMS

As growing concerns exist regarding phthalate exposure, which could be teratogenic, carcinogenic or induce reproductive toxicity, we aimed to review the evidence of the risks due to the use of medical devices containing di(2-ethylhexyl)phthalate in hospitalized neonates.

METHODS

We reviewed the literature, searching through medical literature databases (Pubmed, MEDLINE, EBM reviews, Cochrane database, Embase and Google Scholar) using the following keywords: phthalate, di(2-ethylhexyl)phthalate, newborn and neonate.

RESULTS

We identified several associations with short and long term health dangers, mainly subfertility, broncho-pulmonary dysplasia, necrotising enterocolitis, parenteral nutrition associated cholestasis and neuro-developmental disorders. These data are based mainly on animal or observational human studies.

CONCLUSION

Clinicians must be aware of the potential risks due to phthalate exposure in the NICU. Di(2-ethylhexyl)phthalate containing materials should be identified and alternative devices should be considered. There is a need to improve knowledge in this area.

Phthalate is associated with insulin resistance in adipose tissue of male rat: role of antioxidant vitamins

Diethyl hexyl phthalate (DEHP) is a plasticizer, commonly used in a variety of products, including lubricants, perfumes, hairsprays and cosmetics, construction materials, wood finishers, adhesives, floorings and paints. DEHP is an endocrine disruptor and it has a continuum of influence on various organ systems in human beings and experimental animals. However, specific effects of DEHP on insulin signaling in adipose tissue are not known. Adult male albino rats of Wistar strain were divided into four groups. Control, DEHP treated (dissolved in olive oil at a dose of 10, and 100 mg/kg body weight, respectively, once daily through gastric intubations for 30 days) and DEHP + vitamin E (50 mg/kg body weight) and C (100 mg/kg body weight) dissolved in olive oil and distilled water, respectively, once daily through gastric intubations for 30 days. After the completion of treatment, adipose tissue was dissected out to assess various parameters. DEHP treatment escalated H(2)O(2) and hydroxyl radical levels as well as lipid peroxidation in the adipose tissue. DEHP impaired the expression of insulin signaling molecules and their phosphorelay pathways leading to diminish plasma membrane GLUT4 level and thus decreased glucose uptake and oxidation. Blood glucose level was elevated as a result of these changes. Supplementation of vitamins (C & E) prevented the DEHP-induced changes. It is concluded that DEHP-induced ROS and lipid peroxidation disrupts the insulin signal transduction in adipose tissue and favors glucose intolerance. Antioxidant vitamins have a protective role against the adverse effect of DEHP.

Biological impact of phthalates

Esters of phthalic acid are chemical agents used to improve the plasticity of industrial polymers. Their ubiquitous use in multiple commercial products results in extensive exposure to humans and the environment. This study investigated cytotoxicity, endocrine disruption, effects mediated via AhR, lipid peroxidation and effects on expression of enzymes of xenobiotic metabolism caused by di-(2-ethy hexyl) phthalate (DEHP), diethyl phthalate (DEP), dibutyl phthalate (DBP) and benzyl butyl phthalate (BBP) in developing fish embryos. Oxidative stress was identified as the critical mechanism of toxicity (CMTA) in the case of DEHP and DEP, while the efficient removal of DBP and BBP by phase 1 enzymes resulted in lesser toxicity. DEHP and DEP did not mimic estradiol (E(2)) in transactivation studies, but at concentrations of 10mg/L synthesis of sex steroid hormones was affected. Exposure to 10mg BBP/L resulted in weak transactivation of the estrogen receptor (ER). All phthalates exhibited weak potency as agonists of the aryl hydrocarbon receptor (AhR). The order of potency of the 4 phthalates studied was; DEHP>DEP>BBP>>DBP. The study highlights the need for simultaneous assessment of: (1) multiple cellular targets affected by phthalates and (2) phthalate mixtures to account for additive effects when multiple phthalates modulate the same pathway. Such cumulative assessment of multiple biological parameters is more realistic, and offers the possibility of more accurately identifying the CMTA.

Environmental Toxicology: Children at Risk

Children today live in a world that is vastly different from a few generations ago. While industrialization has maximized (for many) children’s opportunities to survive, develop and enjoy high levels of health, education, recreation, and fulfillment, it has also added significant challenges to their development.

Phthalates dietary exposure and food sources for Belgian preschool children and adults

Numerous studies have indicated that for phthalates, the intake of contaminated foods is the most important exposure pathway for the general population. Up to now, data on dietary phthalate intake are scarce and - to the authors' knowledge - not available for the Belgian population. Therefore, the purpose of this study was: (1) to assess the long-term intake of the Belgian population for eight phthalates considering different exposure scenarios (benzylbutyl phthalate (BBP); di-n-butyl phthalate (DnBP); dicyclohexyl phthalate (DCHP); di(2-ethylhexyl) phthalate (DEHP); diethyl phthalate (DEP); diisobutyl phthalate (DiBP); dimethyl phthalate (DMP), di-n-octyl phthalate (DnOP)); (2) to evaluate the intake of BBP, DnBP, DEP and DEHP against tolerable daily intake (TDI) values; and (3) to assess the contribution of the different food groups to the phthalate intake. The intake assessment was performed using two Belgian food consumption databases, one with consumption data of preschool children (2.5 to 6.5 years old) and another of adults (≥15 years old), combined with a database of phthalate concentrations measured in over 550 food products sold on the Belgian market. Phthalate intake was calculated using the 'Monte Carlo Risk Assessment' programme (MCRA 7.0). The intake of DEHP was the highest, followed by DiBP. The intake of BBP, DnBP and DEP was far below the TDI for both children and adults. However, for DEHP, the 99th percentile of the intake distribution of preschoolers in the worst case exposure scenario was equal to 80% of the TDI, respectively. This is not negligible, since other exposure routes of DEHP exist for children as well (e.g. mouthing of toys). Bread was the most important contributor to the DEHP intake and this may deserve further exploration, since the origin of this phthalate in bread remains unclear.

Aqueous leaching of di-2-ethylhexyl phthalate and "green" plasticizers from poly(vinyl chloride)

A method was developed to assess leaching of several poly(vinyl chloride) (PVC) plasticizers in aqueous media using gas chromatography (GC), and compared to a gravimetric standard test method (ASTM Method D1239). The GC method was a more direct measurement of plasticizer concentration in the aqueous phase. The leaching of commercial plasticizers, as well as several series of "green" candidate plasticizers, were assessed as a function of their molecular characteristics and compared to the industry standard PVC plasticizer, di-2-ethylhexyl phthalate (DEHP). It was found that plasticizers containing longer alkyl chains or non-polar branching emanating from polar structural units, increased the hydrophobicity of the molecule and reduced its aqueous leaching rate. Several "green" plasticizer candidates were found to minimize aqueous leaching to rates ten times below that of DEHP; notably dioctyl succinate (DOS), dihexyl maleate (DHM), methyl cyclohexyl diester (MCDE), diethylhexyl succinate (DEHS), hexanediol dibenzoate (C6), and the commercially available Hexamoll® DINCH.

Strong variability of di(2-ethylhexyl)phthalate (DEHP) plasmatic rate in infants and children undergoing 12-hour cyclic parenteral nutrition

BACKGROUND

Medical devices such as perfusion materials in polyvinyl chloride may contain di(2-ethylhexyl)phthalate (DEHP). Several studies have questioned the harmlessness of phthalates, which have been shown to have toxic effects on the reproductive system and general development. This study was designed to assess DEHP exposure in infants and children benefitting from cyclic parenteral nutrition (PN). The results are compared with those obtained from children used as controls and receiving no PN, to estimate the potential risk to this pediatric population, taking into account exposure levels and already published data.

METHODS

Plasmatic concentrations of DEHP were assessed by high-performance liquid chromatography from blood samples taken from 22 children at the start and finish of a 12-hour cyclic PN period and compared with those obtained from 20 control children of comparable age and gender.

RESULTS

After a 12-hour cyclic PN period, DEHP migration varied widely among the patients. The concentrations were not quantifiable in 4 children at the start of PN. In 1 child, they were quantifiable neither at the start nor at the end of PN. However, for 17 children, DEHP concentrations were quantifiable at the start of PN and were very variable from one child to another. At the end, DEHP concentrations had significantly but variably increased in these children. No trace of DEHP was found in the blood samples from 20 healthy controls.

CONCLUSION

Considering published data on phthalate toxicity, it would appear advisable to encourage the use of medical devices that are either phthalate or DEHP free.

Socioeconomic factors and phthalate metabolite concentrations among United States women of reproductive age

INTRODUCTION

Relatively little is known about the socioeconomic correlates of phthalate metabolite urine concentrations among the general population, exposures of increasing public health concern, particularly for women of reproductive age.

METHODS

We pooled data from the 2001-2008 cycles of the National Health and Nutrition Examination Survey to examine the associations between phthalate metabolite concentrations (including the molar sum of four di-2-ethylhexyl phthalate (DEHP) metabolites, the molar sum of two dibutyl phthalate (DBP) metabolites, and metabolites of benzylbutyl phthalate (BzBP) and diethyl phthalate (DEP)) with socioeconomic indicators (including ethnicity, education, income, and food security status) among women 20 to 39 years age. We also derived a socioeconomic status summary measure using factor analysis and investigated its associations with metabolite concentrations.

RESULTS

In fully adjusted models, the lowest quartile of overall socioeconomic status was associated with 1.83 (95% CI=1.54-2.17) times the concentrations of mono-benzyl phthalate (MBzP), and 0.72 (95% CI=0.54-0.98) times the concentrations of (molar sum) DEHP metabolites compared with the highest quartile of overall socioeconomic status. This latter association was driven primarily by educational attainment. All Non-White ethnicities combined had 1.24 (95% CI=1.09-1.40) times the concentrations of (molar sum) DBP metabolites, 1.32 (95% CI=1.12-1.56) times the mono-ethyl phthalate (MEP) concentrations, and 0.82 (95% CI=0.71-0.96) the concentrations of MBzP of Non-Hispanic Whites.

CONCLUSIONS

Biomarkers of phthalate exposure vary with socioeconomic factors in women of reproductive age in the United States. Given the public health concern surrounding phthalate exposure, more research is needed to elucidate the reasons for these differences.

Di (2-ethylhexyl) phthalate modulates cholinergic mini-presynaptic transmission of projection neurons in Drosophila antennal lobe

Di (2-ethylhexyl) phthalate (DEHP) is one of the Phthalic acid esters which are added in polyvinyl chloride (PVC) products. Previous animal studies have showed that exposure to DEHP has a negative effect on the liver, kidneys, lungs, and reproductive system, particularly the developing testes of prenatal and neonatal males, but few can match the dramatic impact on the nervous system. Drosophila melanogaster as a model organism has been widely used in research of the nervous system. In order to examine the modulation of DEHP in excitatory cholinergic transmission, electrophysiological properties of spontaneous activities, spontaneous action potential (sAP), mini excitatory postsynaptic currents (mEPSCs), and calcium currents were measured in projection neurons (PNs) of Drosophila antennal lobe. In this study, DEHP (100μM) was showed to influence the spontaneous activities of the PNs and DEHP (300 μM) significantly decrease the frequency of sAP. Meanwhile, DEHP (100 and 300 μM) also reduced the frequency and amplitude of mEPSCs. Furthermore, ion channel studies showed DEHP (100 and 300 μM) inhibited the peak current amplitude of calcium channel. These results indicated that the DEHP modulated the cholinergic mini-synaptic transmission of projection neurons in Drosophila antennal lobe, and this modulation might be mediated by inhibiting the calcium channel activities.

Phosphonium-based ionic liquids as modifiers for biomedical grade poly(vinyl chloride)

This work reports and discusses the influence of four phosphonium-based ionic liquids (PhILs), namely trihexyl(tetradecyl) phosphonium dicyanamide, [P(6,6,6,14)][dca]; trihexyl(tetradecyl) phosphonium bis(trifluoromethylsulfonyl)imide, [P(6,6,6,14)][Tf(2)N]; tetrabutyl phosphonium bromide, [P(4,4,4,4)][Br]; and tetrabutyl phosphonium chloride, [P(4,4,4,4)][Cl], on some of the chemical, physical and biological properties of a biomedical-grade suspension of poly(vinyl chloride) (PVC). The main goal of this work was to evaluate the capacity of these PhILs to modify some of the properties of neat PVC, in particular those that may allow their use as potential alternatives to traditional phthalate-based plasticizers in PVC biomedical applications. PVC films having different PhIL compositions (0, 5, 10 and 20 wt.%) were prepared (by solvent film casting) and characterised by Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetry, dynamical mechanical thermal analysis, scanning electron microscopy/energy-dispersive X-ray/electron probe microanalysis, X-ray diffraction, transmittance, permeability towards oxygen and carbon dioxide, thermal degradation, contact angle measurement, water and vapour uptake, leachability and biocompatibility (haemolytic potential, thrombogenicity and cytotoxicity). A conventional organic plasticizer (di-isononyl phthalate) was used for comparison purposes. The results obtained showed that it was possible to change the neat PVC hydrophobicity, and consequently its water uptake capacity and plasticizer leachability, just by changing the PhIL employed and its composition. It was also possible to significantly change the thermal and mechanical properties of PVC films by choosing appropriate PhIL cation/anion combinations. However, a specific PhIL may not always be capable of simultaneously keeping and/or improving both physical properties. In addition, ionic halide salts were found to promote PVC dehydrochlorination. Finally, none of the prepared materials presented toxicity against Caco-2 cells, though pure [P(6,6,6,14)][dca] decreased HepG2 cells viability. Moreover, PVC films with [P(6,6,6,14)][dca] and [P(4,4,4,4)][Cl] were found to be haemolytic and thus these PhILs must be avoided as PVC modifiers if biomedical applications are envisaged. In conclusion, from all the PhILs tested, [P(6,6,6,14)][Tf(2)N] showed the most promising results regarding blood compatibility, leaching and permeability to gases of PVC films. The results presented are a strong indicator that adequate PhILs may be successfully employed as PVC multi-functional plasticizers for a wide range of potential applications, including those in the biomedical field.

A review of alternatives to di (2-ethylhexyl) phthalate-containing medical devices in the neonatal intensive care unit

OBJECTIVE

To conduct an extensive literature and toxicological database review on substitute compounds and available alternative medical products to replace polyvinyl chloride (PVC) and/or di(2-ethylhexyl) phthalate (DEHP), and conduct a DEHP-medical inventory analysis at a large metropolitan neonatal intensive care unit (NICU).

STUDY DESIGN

A systematic search for DEHP-free alternative products was performed using online databases. An informal audit of a large metropolitan NICU was undertaken in 2005 and 2006; 21 products were identified that could potentially contain DEHP. Availability of DEHP-free alternatives was determined through company websites and phone interviews.

RESULT

Two alternative approaches are available for replacing DEHP in NICU medical products: (1) replacement by DEHP-free plasticizers; and (2) replacement of PVC entirely through the use of other polymers. Both approaches seem to provide less harmful substitutes to DEHP, but support PVC-free polymers as the preferred alternative. However, significant data gaps exist, particularly for the alternative polymers. In all, 10 out of 21 (48%) products in the NICU audit were DEHP-free; six consisted of alternative polymers and four of alternative plasticizers. Of the remaining 11 products, only three were available without DEHP at the time of the audit.

CONCLUSION

Because of significant data gaps, systematic toxicological testing of DEHP-free alternatives is imperative. Continued development of alternative products is also needed.

Phthalate exposures and human health concerns: A review and implications for practice

High levels of exposure to phthalates have been associated with an increased risk for adverse male fetal reproductive development. Although animal studies have consistently demonstrated reproductive health effects, additional human epidemiological studies are needed to fully understand the potential harm to humans. Recent findings reported for humans have demonstrated endocrine-disrupting action similar to that associated with phthalate exposures in animals. As a result, phthalate exposure is an emerging public health concern that warrants further review. This article explores the state of the science on phthalate exposure, reviews the literature, and provides recommendations occupational health nurses can use to optimize the health of susceptible populations.

Exposure to phthalates: reproductive outcome and children health. A review of epidemiological studies

Phthalates are a family of industrial chemicals that have been used for a variety of purposes. As the potential consequences of human exposure to phthalates have raised concerns in the general population, they have been studied in susceptible subjects such as pregnant women, infants and children. This article aims at evaluating the impact of exposure to phthalates on reproductive outcomes and children health by reviewing most recent published literature. Epidemiological studies focusing on exposure to phthalates and pregnancy outcome, genital development, semen quality, precocious puberty, thyroid function, respiratory symptoms and neurodevelopment in children for the last ten years were identified by a search of the PubMed, Medline, Ebsco, Agricola and Toxnet literature bases. The results from the presented studies suggest that there are strong and rather consistent indications that phthalates increase the risk of allergy and asthma and have an adverse impact on children's neurodevelopment reflected by quality of alertness among girls, decreased (less masculine) composite score in boys and attention deficit hyperactivity disorder. Results of few studies demonstrate negative associations between phthalate levels commonly experienced by the public and impaired sperm quality (concentration, morphology, motility). Phthalates negatively impact also on gestational age and head circumference; however, the results of the studies were not consistent. In all the reviewed studies, exposure to phthalates adversely affected the level of reproductive hormones (luteinizing hormone, free testosterone, sex hormone-binding globulin), anogenital distance and thyroid function. The urinary levels of phthalates were significantly higher in the pubertal gynecomastia group, in serum in girls with premature thelarche and in girls with precocious puberty. Epidemiological studies, in spite of their limitations, suggest that phthalates may affect reproductive outcome and children health. Considering the suggested health effects, more epidemiologic data is urgently needed and, in the meantime, precautionary policies must be implemented.

Phthalate Exposures and Human Health Concerns

High levels of exposure to phthalates have been associated with an increased risk for adverse male fetal reproductive development. Although animal studies have consistently demonstrated reproductive health effects, additional human epidemiological studies are needed to fully understand the potential harm to humans. Recent findings reported for humans have demonstrated endocrine-disrupting action similar to that associated with phthalate exposures in animals. As a result, phthalate exposure is an emerging public health concern that warrants further review. This article explores the state of the science on phthalate exposure, reviews the literature, and provides recommendations occupational health nurses can use to optimize the health of susceptible populations.

Experimental study on infusion devices containing polyvinyl chloride: to what extent are they di(2-ethylhexyl)phthalate-free?

The use of medical devices containing highly criticized phthalates including di(2-ethylhexyl) phthalate (DEHP) has been challenged by European directive 2007/47/CE, put into effect in March 2010. New plasticizers are now being used to soften PVC in medical devices: trioctyltrimellitate (TOTM), di-isononyl-cyclohexan-1,2-dicarboxilate (DINCH) and di(2-ethylhexyl) terephthalate (DEHT). To quantify DEHP in nine DEHP-free medical devices made of PVC softened by alternative plasticizers, high performance liquid chromatography analysis with ultraviolet detection at 220 nm wavelength was achieved. An NMR spectroscopy was performed to confirm DEHP presence. Only two medical devices out of the nine tested were truly without DEHP. One of them showed traces of DEHP exceeding the threshold contamination of 0.1% in plastic mass set by REACH regulations. TOTM plasticizer is still incriminated when polyvinyl-chloride (PVC) is contaminated with DEHP. Manufacturers must verify the purity of their raw material, not only on PVC, but also on other soft plastics entering into the composition of medical infusion devices. The clinical consequences of exposure to certain levels of DEHP have not been evaluated. A solution could be to use alternative PVC-free materials.

Endocrine disruptors, travel-associated illness, and media violence: important health considerations for children and adolescents

PURPOSE OF REVIEW

This article addresses three important topics that are part of contemporary life for children: endocrine disruptors, hazards of international travel, and the impact of media violence on children and adolescents.

RECENT FINDINGS

Practitioners will learn about phthalates and Bisphenol-A as endocrine disruptors. In published studies, elevated phthalates were associated with an increase in pubertal gynecomastia and premature thelarche. Bisphenol-A was judged by the Food and Drug Administration as having some concern for potential effects on brain, behavior, and prostate gland in fetuses, infants, and young children: hence, the decision to take reasonable steps to reduce exposure of infants. In travel-related diseases, diarrheal disease (primarily Campylobacter and Salmonella), dermatologic conditions (animal bites), systemic febrile illness (malaria and dengue fever), and respiratory illnesses predominate. Children and adolescents spend more than 7 h using media per day. The degree to which media violence can be linked to behavior is not conclusive, but the prevention message for practitioners is important because parents can have an important mitigating effect.

SUMMARY

Endocrine disruptors, travel-related diseases, and media violence are part of modern day life for our children. Pediatricians need to stay abreast of recent findings and have access to up-to-date resources to assist them in providing contemporary advice and guidance to patients and families.

Gene expression profiling of DEHP-treated cardiomyocytes reveals potential causes of phthalate arrhythmogenicity

BACKGROUND

Di-(2-ethylhexyl)-phthalate (DEHP) is a widely used plasticizer that imparts flexibility to polyvinyl chloride. We have recently reported that clinically relevant concentrations of DEHP can affect electrical coupling between cardiac myocytes causing significant rhythm disturbances. The underlying causes for this effect are currently unknown.

OBJECTIVES

To use data on global mRNA expression as a tool to reveal possible pathways leading to arrhythmogenic effects of DEHP.

METHODS

Rat neonatal cardiomyocytes were treated with 50 μg/mL DEHP for 72 h. Extracted RNA samples were hybridized onto Affymetrix Rat Gene 1.0 ST arrays. The mRNA expression of a subset of genes was validated by qRT-PCR. In a second set of experiments, cells were treated in a concentration dependent manner to identify genes affected by low DEHP concentrations.

RESULTS

DEHP exposure is associated with global changes in mRNA expression, with differentially expressed genes overrepresented in 47 Gene Ontology categories. Modified expression was detected for genes associated with cell electrical activity, calcium handling, adhesion and microtubular transport. For a number of key proteins, including kinesin, TGFβ2, α-tubulin, and α1 & β1 integrins, changes in mRNA levels were confirmed on the level of the protein expression. A number of genes associated with cell adhesion and electrical activity were identified as early DEHP targets as they were affected by concentrations as low as 1 μg/mL.

CONCLUSIONS

Exposure of neonatal rat cardiomyocytes to clinically relevant DEHP concentrations leads to global changes in mRNA expression. These changes help to explain the arrhythmogenic effects of phthalates on these cells.

Inflammatory effects of phthalates in neonatal neutrophils

Hospitalized infants are exposed to numerous devices containing the plasticizer di-(2-ethylhexyl) phthalate. Urinary levels of the phthalate metabolite, mono-(2-ethylhexyl) phthalate (MEHP), are markedly elevated in premature infants. Phthalates inactivate peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a nuclear transcription factor that mediates the resolution of inflammation, a process impaired in neonates. We speculate that this increases their susceptibility to MEHP, and this was analyzed. MEHP inhibited neutrophil apoptosis; neonatal cells were more sensitive than adult cells. In neonatal, but not in adult neutrophils, MEHP also inhibited chemotaxis, stimulated oxidative metabolism, and up-regulated expression of NADPH oxidase-1. In both adult and neonatal neutrophils, MEHP stimulated IL-1beta and VEGF production, whereas IL-8 production was stimulated only in adult cells. In contrast, MEHP-inhibited production of MIP-1beta by adult cells, and Regulated on Activation Normal T Cell Expressed and Secreted (RANTES) by neonatal neutrophils. The effects of MEHP on apoptosis and oxidative metabolism in neonatal cells were reversed by the PPAR-gamma agonist, troglitazone. Whereas troglitazone had no effect on MEHP-induced alterations in inflammatory protein or chemokine production, constitutive IL-8 and MIP-1beta production was reduced in adult neutrophils, and RANTES and MIP-1beta in neonatal cells. These findings suggest that neonatal neutrophils are more sensitive to phthalate-mediated inhibition of PPAR-gamma, which may be related to decreased anti-inflammatory signaling.

Relationship between environmental phthalate exposure and the intelligence of school-age children

BACKGROUND

Concern over phthalates has emerged because of their potential toxicity to humans.

OBJECTIVE

We investigated the relationship between the urinary concentrations of phthalate metabolites and children's intellectual functioning.

METHODS

This study enrolled 667 children at nine elementary schools in five South Korean cities. A cross-sectional examination of urine phthalate concentrations was performed, and scores on neuropsychological tests were obtained from both the children and their mothers.

RESULTS

We measured mono-2-ethylhexyl phthalate (MEHP) and mono(2-ethyl-5-oxohexyl)phthalate (MEOHP), both metabolites of di(2-ethylhexyl)phthalate (DEHP), and mono-n-butyl phthalate (MBP), a metabolite of dibutyl phthalate (DBP), in urine samples. The geometric mean (ln) concentrations of MEHP, MEOHP, and MBP were 21.3 microg/L [geometric SD (GSD) = 2.2 microg/L; range, 0.5-445.4], 18.0 microg/L (GSD = 2.4; range, 0.07-291.1), and 48.9 microg/L (GSD = 2.2; range, 2.1-1645.5), respectively. After adjusting for demographic and developmental covariates, the Full Scale IQ and Verbal IQ scores were negatively associated with DEHP metabolites but not with DBP metabolites. We also found a significant negative relationship between the urine concentrations of the metabolites of DEHP and DBP and children's vocabulary subscores. After controlling for maternal IQ, a significant inverse relationship between DEHP metabolites and vocabulary subscale score remained. Among boys, we found a negative association between increasing MEHP phthalate concentrations and the sum of DEHP metabolite concentrations and Wechsler Intelligence Scale for Children vocabulary score; however, among girls, we found no significant association between these variables.

CONCLUSION

Controlling for maternal IQ and other covariates, the results show an inverse relationship between phthalate metabolites and IQ scores; however, given the limitations in cross-sectional epidemiology, prospective studies are needed to fully explore these associations.

Phthalate exposure and precocious puberty in females

OBJECTIVE

To determine whether phthalate exposure is associated with precocious puberty in girls.

STUDY DESIGN

This was a multicenter cross-sectional study in which 28 girls with central precocious puberty (CPP) and 28 age- and race-matched prepubertal females were enrolled. Nine phthalate metabolites and creatinine were measured in spot urine samples from these 56 children.

RESULTS

Levels of 8 of the 9 phthalate metabolites were above the limit of detection (LOD) in all 56 subjects. Mono (2-ethylhexyl) phthalate (MEHP) was below the LOD in 25/56 samples (14 subjects with precocious puberty and 11 controls). No significant differences between the children with CPP and the controls in either absolute or creatinine-normalized concentrations of any of the 9 phthalate metabolites were measured.

CONCLUSIONS

Although phthalates may be associated with certain other toxicities in humans, our study suggests that their exposure is not associated with precocious puberty in female children.

Plasma phthalate levels in pubertal gynecomastia

OBJECTIVE

Several untoward health effects of phthalates, which are a group of industrial chemicals with many commercial uses including personal-care products and plastic materials, have been defined. The most commonly used, di-(2-ethylhexyl)-phthalate (DEHP), is known to have antiandrogenic or estrogenic effects or both. Mono-(2-ethylhexyl)-phthalate (MEHP) is the main metabolite of DEHP. In this study, we aimed to determine the plasma DEHP and MEHP levels in pubertal gynecomastia cases.

PATIENTS AND METHODS

The study group comprised 40 newly diagnosed pubertal gynecomastia cases who were admitted to Hacettepe University Ihsan Doğramaci Children's Hospital. The control group comprised 21 age-matched children without gynecomastia or other endocrinologic disorder. Plasma DEHP and MEHP levels were measured by using high-performance liquid chromatography. Serum hormone levels were determined in some pubertal gynecomastia cases according to the physician's evaluation.

RESULTS

Plasma DEHP and MEHP levels were found to be statistically significantly higher in the pubertal gynecomastia group compared with the control group (P < .001) (DEHP, 4.66 +/- 1.58 and 3.09 +/- 0.90 microg/mL, respectively [odds ratio: 2.77 (95% confidence interval: 1.48-5.21)]; MEHP, 3.19 +/- 1.41 and 1.37 +/- 0.36 microg/mL [odds ratio: 24.76 (95% confidence interval: 3.5-172.6)]). There was a statistically significant correlation between plasma DEHP and MEHP levels (r: 0.58; P < .001). In the pubertal gynecomastia group, no correlation could be determined between plasma DEHP and MEHP levels and any of the hormone levels.

CONCLUSIONS

DEHP, which has antiandrogenic or estrogenic effects, may be an etiologic factor in pubertal gynecomastia. These results may pioneer larger-scale studies on the etiologic role of DEHP in pubertal gynecomastia.

Biodegradation of diisodecyl phthalate (DIDP) by Bacillus sp. SB-007

In this study, diisodecyl phthalate (DIDP) was efficiently degraded by Bacillus sp. SB-007. The optimal conditions for DIDP (100 mg l(-1)) degradation by Bacillus sp. SB-007 in a mineral salts medium were found to be pH 7.0 at 30 degrees C, stirring at 200 rpm. The specific rate of DIDP degradation was found to be concentration dependent with a maximum of 4.87 mg DIDP l(-1) h(-1). DIDP was transformed rapidly by Bacillus sp. SB-007 with the formation of monoisodecyl phthalate and phthalic acid, which subsequently degraded further. These results highlight the potential of this bacterium for removing DIDP contaminated waste in the environment.

Phthalate metabolites in urine of CF patients are associated with use of enteric-coated pancreatic enzymes

In metabolomic studies using liquid chromatography mass spectrometry of urine from children with cystic fibrosis (CF), high levels of metabolites of low molecular weight phthalates were found. Phthalate metabolite excretion was explained by therapy with enteric-coated pancreatic enzyme replacements. Phthalate metabolite identity was confirmed by tandem mass spectrometry. Pancreatic insufficient CF children taking Cotazym ECS(®), which is formulated with diethyl phthalate (DEP), had urinary metabolites of DEP. Children taking Creon(®), which has dibutyl phthalate (DBP), excreted DBP metabolites. The estimated concentrations of free MEP were 2-3 orders of magnitude higher than reported from environmental phthalate exposure. Enteric-coated pancreatic enzymes can expose individuals with CF to incessant, high oral intakes of phthalates. Although adverse effects have neither been shown to be present nor absent, we raise the need to consider that individuals requiring life-long therapy with some current pancreatic enzyme replacements chronically ingest high amounts of phthalates.

Material wear of polymeric tracheostomy tubes: a six-month study

OBJECTIVES

The objectives were to study long-term material wear of tracheostomy tubes made of silicone (Si), polyvinyl chloride (PVC), and polyurethane (PU) after 3 and 6 months of clinical use.

STUDY DESIGN

The study has a prospective and comparative design.

METHODS

Nineteen patients with long-term tracheostomy, attending the National Respiratory Center in Sweden, were included, n = 6 with Si tubes, n = 8 with PVC tubes, and n = 5 with PU tubes. The tubes were exposed to the local environment in the trachea for 3 and 6 months and analyzed by scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, and differential scanning calorimetry.

RESULTS

All tubes revealed severe surface changes. No significant differences were established after 3 or 6 months of exposure between the various materials. The changes had progressed significantly after this period, compared to previously reported changes after 30 days of exposure. The results from all analyzing techniques correlated well.

CONCLUSIONS

All tubes, exposed in the trachea for 3-6 months, revealed major degradation and changes in the surface of the material. Polymeric tracheostomy tubes should be changed before the end of 3 months of clinical use.