Extraction of the plasticizers diethylhexylphthalate and polyadipate from polyvinylchloride nasogastric tubes through gastric juice and feeding solution

Phthalates cause a low-renin phenotype commonly found in premature infants with idiopathic neonatal hypertension

Since the 1970s, when the initial reports of neonatal hypertension related to renal artery thromboembolism were published, other secondary causes of neonatal hypertension have been reported. Those infants with no identifiable cause of hypertension were labeled with a variety of terms. Herein, we describe such infants as having idiopathic neonatal hypertension (INH). Most, but not all, of these hypertensive infants were noted to have bronchopulmonary dysplasia (BPD). More recently, reports described common clinical characteristics seen in INH patients, whether or not they had BPD. This phenotype includes low plasma renin activity, presentation near 40 weeks postmenstrual age, and a favorable response to treatment with spironolactone. A small prospective study in INH patents showed evidence of mineralocorticoid receptor activation due to inhibition of 11β-HSD2, the enzyme that converts cortisol to the less potent mineralocorticoid-cortisone. Meanwhile, phthalate metabolites have been shown to inhibit 11β-HSD2 in human microsomes. Premature infants can come in contact with exceptionally large phthalate exposures, especially those infants with BPD. This work describes a common low-renin phenotype, commonly seen in patients categorized as having INH. Further, we review the evidence that hypertension in INH patients with the low-renin phenotype may be mediated by phthalate-associated inhibition of 11β-HSD2. Lastly, we review the implications of these findings regarding identification, treatment, and prevention of the low-renin hypertension phenotype seen in premature infants categorized as having INH.

Nasogastric Tube Syndrome: The Size and Type of the Nasogastric Tube May Contribute to the Development of Nasogastric Tube Syndrome

Nasogastric tube syndrome (NGTS) is a rare but life-threatening complication associated with nasogastric tube (NGT) placement. The effect of the NGT size and type on the development of NGTS has not yet been fully elucidated. We herein report the case of a 77-year-old man with cerebral infarction who was complicated with NGTS. The immediate removal of the NGT improved the symptoms of NGTS. Although the NGT was passed through the same route during reinsertion, the use of a softer and smaller-sized NGT did not cause any NGTS recurrence. To prevent the development of NGTS, using a NGT that is appropriate for the patient's condition is important.

Phthalate Exposures in the Neonatal Intensive Care Unit

Background: Di-2-ethylhexyl phthalate (DEHP), a phthalate compound found in medical devices, may cause toxic effects in premature infants. In this study, the objective is to quantify DEHP exposures from various intravenous and respiratory therapy devices, and to use these values to predict typical exposure for an infant in a neonatal unit. Methods: Common IV products used on infants are directed through various types of IV tubing (IVT) and analyzed for DEHP content. DEHP exposure for infants receiving respiratory therapy was determined indirectly through analysis of urine DEHP metabolites. By deriving these values for DEHP we calculated the daily exposure to DEHP from common IV fluids (IVF) and respiratory devices during hospitalization in a neonatal unit. Results: IVF labeled DEHP-positive showed very high concentrations of DEHP, but when passed through IVT, substantial amounts were adsorbed. DEHP was undetectable with all DEHP-negative IVF tests, except when passed through DEHP-positive IVT. The DEHP leached from most respiratory devices was relatively modest, except that detected from bubble CPAP. In 14 very low birthweight infants, the mean DEHP exposure was 182,369 mcg/kg over 81.2 days of the initial hospitalization. Ninety-eight percent of the exposure was from respiratory devices, with bubble CPAP accounting for 95% of the total DEHP exposure in these infants. Conclusions: The DEHP exposure in our neonatal unit can be reduced markedly by avoiding or modifying bubble CPAP equipment and avoiding IV tubing containing DEHP.

Pharmaceutical Aspects of Artificial Nutrition

Artificial nutrition, including enteral (EN) and parenteral (PN) nutrition, is indicated whenever adequate oral nutrition fails to sufficiently supply the necessary nutrients to the body. It is a convenient, efficacious, safe, and well-tolerated form of clinical nutrition in the hospital and home setting. EN is administered via nasogastric tube or ostomies while PN usually requires a central venous access for administration, straight into the blood stream. The infused nutrients can then be taken up directly by the different organs. PN is targeted as a single daily portion formulated as an oil-in-water emulsion providing the necessary substrates for the catabolic and anabolic metabolism including macro- and micronutrients and fluids. PN has a complex pharmaceutical composition-all-in-one admixture-and its compounding or ready-to-use preparation. The use of PN is more challenging and more expensive compare to the use of EN, commercially available as ready-to-use formulations. EN and concomitant medication is highly challenging. Upon incorrect handling and administration, PN is associated with potentially severe or even fatal complications, mostly relating to the central venous access (e.g., catheter-related sepsis) or to a metabolic intolerance (e.g., hyperglycemia, refeeding syndrome) because of inappropriate administration. A correct order of admixing, correct dosing, and administration of the artificial is crucial for safety and efficacy; clinical and biochemical monitoring of the patient and treatment regimen adaption are necessary. The high number of reactive solutes allow only limited stability of a ready-to-use PN admixture. The potential for numerous incompatibilities and interactions renders PN admixtures generally unsuitable as drug vehicle. Laboratory compatibility and stability testing and pharmaceutical expertise are a prerequisite to define the PN composition including nutrients or even drugs admixed to define the appropriate and individualized nutrition and medication regimen. The aim of this narrative review is to present the actual state-of-the-art to deliver best quality artificial nutrition with special regard on pharmaceutical aspects such as instabilities, incompatibilities, and concomitant co-medication.

Phthalate-associated hypertension in premature infants: a prospective mechanistic cohort study

BACKGROUND

Phthalates are associated with increased blood pressure in children. Large exposures to di-(2-ethylhexyl) phthalate (DEHP) among premature infants have been a cause for concern.

METHODS

We conducted a prospective observational cohort study to determine if DEHP exposures are related to systolic blood pressure (SBP) in premature infants, and if this exposure is associated with activation of the mineralocorticoid receptor (MR). Infants were monitored longitudinally for 8 months from birth. Those who developed idiopathic hypertension were compared with normotensive infants for DEHP exposures. Appearance of urinary metabolites after exposure was documented. Linear regression evaluated the relationship between DEHP exposures and SBP index and whether urinary cortisol/cortisone ratio (a surrogate marker for 11β-HSD2 activity) mediated those relationships. Urinary exosomes were quantified for sodium transporter/channel expression and interrogated against SBP index.

RESULTS

Eighteen patients met the study criteria, nine developed transient idiopathic hypertension at a postmenstrual age of 40.6 ± 3.4 weeks. The presence of urinary DEHP metabolites was associated with prior IV and respiratory tubing DEHP exposures (p < 0.05). Both IV and respiratory DEHP exposures were greater in hypertensive infants (p < 0.05). SBP index was related to DEHP exposure from IV fluid (p = 0.018), but not respiratory DEHP. Urinary cortisol/cortisone ratio was related to IV DEHP and SBP index (p < 0.05). Sodium transporter/channel expression was also related to SBP index (p < 0.05).

CONCLUSIONS

Increased blood pressure and hypertension in premature infants are associated with postnatal DEHP exposure. The mechanism of action appears to be activation of the MR through inhibition of 11β-HSD2.

Effects of Phthalates on the Biology of the Mussel Mytilus Galloprovincialis (from the Atlantic Coast of El Jadida, Morocco)

Not available

Studying DEHP migration in plasticized PVC used for blood bags by coupling Raman confocal microscopy to UV spectroscopy

Plasticized PVC is widely used to make medical devices such as tubing, perfusion bags and blood bags. By using confocal Raman microscopy on a PVC sheet plasticized with around 40% of di-(2-ethylhexyl)phthalate (DEHP), we propose a simple and sensitive approach to studying and understanding the diffusion of plasticizers from polymers into the surrounding media. Moreover, we sought to correlate our findings to standard measurements conducted by UV spectroscopy. This study showed differences in the concentration gradient observed due to the diffusion of the plasticizer inside a PVC sheet. We can thus follow the critical DEHP ratios that can impact the diffusion process. Water and ethanol were chosen as storage media: in ethanol, the lowest concentration of DEHP was observed at the surface resulting in the formation of a less plasticized layer near the interface; unlike ethanol, PVC sheets stored in water showed a greater concentration of DEHP on the film surface as an exudation of DEHP onto the surface.

Phthalates and critically ill neonates: device-related exposures and non-endocrine toxic risks

OBJECTIVE

To assess the types and magnitudes of non-endocrine toxic risks to neonates associated with medical device-related exposures to di(2-ethylhexyl)phthalate (DEHP).

STUDY DESIGN

Dose-response thresholds for DEHP toxicities were determined from published data, as were the magnitudes of DEHP exposures resulting from neonatal contact with polyvinyl chloride (PVC) devices. Standard methods of risk assessment were used to determine safe levels of DEHP exposure in neonates, and hazard quotients were calculated for devices individually and in aggregate.

RESULT

Daily intake of DEHP for critically ill preterm infants can reach 16 mg/kg per day, which is on the order of 4000 and 160,000 times higher than desired to avoid reproductive and hepatic toxicities, respectively. The non-endocrine toxicities of DEHP are similar to complications experienced by preterm neonates.

CONCLUSION

DEHP exposures in neonatal intensive care are much higher than estimated safe limits, and might contribute to common early and chronic complications of prematurity. Concerns about phthalates should be expanded beyond endocrine disruption.

Oxidative stress and phthalate-induced down-regulation of steroidogenesis in MA-10 Leydig cells

Previous studies have shown that phthalate exposure can suppress steroidogenesis. However, the affected components of the steroidogenic pathway, and the mechanisms involved, remain uncertain. We show that incubating MA-10 Leydig cells with mono-(2-ethylhexyl) phthalate (MEHP) resulted in reductions in luteinizing hormone (LH)-stimulated cAMP and progesterone productions. cAMP did not decrease in response to MEHP when the cells were incubated with cholera toxin or forskolin. Incubation of MEHP-treated cells with dibutyryl-cAMP, 22-hydroxycholesterol or pregnenolone inhibited the reductions in progesterone. Increased levels of reactive oxygen species (ROS) occurred in response to MEHP. In cells in which intracellular glutathione was depleted by buthionine sulfoximine pretreatment, the increases in ROS and decreases in progesterone in response to MEHP treatment were exacerbated. These results indicate that MEHP inhibits MA-10 Leydig cell steroidogenesis by targeting LH-stimulated cAMP production and cholesterol transport, and that a likely mechanism by which MEHP acts is through increased oxidative stress.

Exposure to di(2-ethylhexyl) phthalate in premature neonates in a neonatal intensive care unit in Taiwan

OBJECTIVE

Neonates are exposed to high levels of di(2ethylhexyl) phthalate through numerous medical procedures in the neonatal intensive care unit. Our aim was to assess the contribution of specific medical devices to the di(2-ethylhexyl) phthalate exposure of neonates.

DESIGN

Prospective.

SETTING

University hospital.

PATIENTS

We recruited 32 premature neonates, 20 with very low birth weight (<1500 g) and 12 with low birth weight (<2500 g), and 31 controls at a neonatal intensive care unit from a medical center in central Taiwan.

INTERVENTIONS

Interventions were based on a clinical need and used standard materials and devices, including endotracheal tubes, continuous positive airway pressure, oxygen hood, intravenous injection, intralipid injection, blood transfusion, orogastric tubes, nasogastric tubes, umbilical venous catheterization, umbilical arterial catheterization, chest tube, and isolate.

MEASUREMENTS AND MAIN RESULTS

We recorded the medical procedures of each subject, collected their urine samples, and determined the urinary concentration of three metabolites of di(2-ethylhexyl) phthalate using reversed-phase high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry. Median levels of di(2-ethylhexyl) phthalate metabolites in premature neonates treated with an endotracheal tube and orogastric tube or nasogastric tube were significantly higher than those not treated with an endotracheal tube, orogastric tube, or nasogastric tube. Median levels of di(2-ethylhexyl) phthalate metabolites in premature neonates treated with intravenous injection were ≥ 2-fold higher than those of healthy controls who received intravenous injections (p = .01). Median levels of three di(2-ethylhexyl) phthalate metabolites were similar in very-low-birth-weight and low-birth-weight neonates.

CONCLUSIONS

These data suggest that polyvinyl chloride-containing devices are the major defining factor in di(2-ethylhexyl) phthalate exposure levels in neonates in the neonatal intensive care unit. We urge the use of polyvinyl chloride-free or alternative materials in medical devices, especially for endotracheal tubes, orogastric tubes, nasogastric tubes, and intravenous tubing in the neonatal intensive care unit. The health effects of high di(2-ethylhexyl) phthalate exposure on premature neonates in the neonatal intensive care unit is worthy of further investigation.

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.

In utero exposure to the antiandrogen di-(2-ethylhexyl) phthalate decreases adrenal aldosterone production in the adult rat

We previously reported that in utero exposure of the male fetus to the plasticizer di-(2-ethylhexyl) phthalate (DEHP) resulted in decreased circulating levels of testosterone in the adult without affecting Leydig cell numbers, luteinizing hormone levels, or steroidogenic enzyme expression. Fetal exposure to DEHP resulted in reduced mineralocorticoid receptor (MR; NR3C2) expression in adult Leydig cells. In the present studies, treatment of pregnant Sprague-Dawley dams from Gestational Day 14 until birth with 20, 50, 100, 300, or 750 mg kg(-1) day(-1) of DEHP resulted in significant sex-specific decreases in serum aldosterone but not corticosterone levels at Postnatal Day 60 (PND60) but not at PND21. There was no effect on circulating levels of potassium, angiotensin II or adrenocorticotropin hormone (ACTH). However, there was reduced expression of AT receptor Agtr1a, Agtr1b, and Agtr2 mRNAs. The mRNA levels of proteins and enzymes implicated in aldosterone biosynthesis were not affected by in utero DEHP treatment except for Cyp11b2, which was decreased at high (≥ 500 mg kg(-1) day(-1)) doses. The data presented herein, together with our previous observation that aldosterone stimulates testosterone production via an MR-mediated mechanism, suggest that in utero exposure to DEHP causes reduction in both adrenal aldosterone synthesis and MR expression in Leydig cells, leading to reduced testosterone production in the adult. Moreover, these results suggest the existence of a DEHP-sensitive adrenal-testis axis regulating androgen formation.

In utero exposure to di-(2-ethylhexyl) phthalate decreases mineralocorticoid receptor expression in the adult testis

In utero exposure to di-(2-ethylhexyl) phthalate (DEHP) has been shown to result in decreased androgen formation by fetal and adult rat testes. In the fetus, decreased androgen is accompanied by the reduced expression of steroidogenic enzymes. The mechanism by which in utero exposure results in reduced androgen formation in the adult, however, is unknown. We hypothesized that deregulation of the nuclear steroid receptors might explain the effects of in utero DEHP exposure on adult testosterone production. To test this hypothesis, pregnant Sprague Dawley dams were gavaged with 100-950 mg DEHP per kilogram per day from gestational d 14-19, and testes were collected at gestational d 20 and postnatal days (PND) 3, 21, and 60. Among the nuclear receptors studied, the mineralocorticoid receptor (MR) mRNA and protein levels were reduced in PND60 interstitial Leydig cells, accompanied by reduced mRNA expression of MR-regulated genes. Methylation-sensitive PCR showed effects on the nuclear receptor subfamilies NR3A and -3C, but only MR was affected at PND60. Pyrosequencing of two CpG islands within the MR gene promoter revealed a loss of methylation in DEHP-treated animals that was correlated with reduced MR. Because MR activation is known to stimulate Leydig cell testosterone formation, and MR inhibition to be repressive, our results are consistent with the hypothesis that in utero exposure to DEHP leads to MR dysfunction and thus to depressed testosterone production in the adult. We suggest that decreased MR, possibly epigenetically mediated, is a novel mechanism by which phthalates may affect diverse functions later in life.

Reproductive and developmental toxicity of phthalates

The purposes of this review are to (1) evaluate human and experimental evidence for adverse effects on reproduction and development in humans, produced by exposure to phthalates, and (2) identify knowledge gaps as for future studies. The widespread use of phthalates in consumer products leads to ubiquitous and constant exposure of humans to these chemicals. Phthalates were postulated to produce endocrine-disrupting effects in rodents, where fetal exposure to these compounds was found to induce developmental and reproductive toxicity. The adverse effects observed in rodent models raised concerns as to whether exposure to phthalates represents a potential health risk to humans. At present, di(2-ethylhexyl) phthalate (DEHP), di-n-butyl phthalate (DBP), and butyl benzyl phthalate (BBP) have been demonstrated to produce reproductive and developmental toxicity; thus, this review focuses on these chemicals. For the general population, DEHP exposure is predominantly via food. The average concentrations of phthalates are highest in children and decrease with age. At present, DEHP exposures in the general population appear to be close to the tolerable daily intake (TDI), suggesting that at least some individuals exceed the TDI. In addition, specific high-risk groups exist with internal levels that are several orders of magnitude above average. Urinary metabolites used as biomarkers for the internal levels provide additional means to determine more specifically phthalate exposure levels in both general and high-risk populations. However, exposure data are not consistent and there are indications that secondary metabolites may be more accurate indicators of the internal exposure compared to primary metabolites. The present human toxicity data are not sufficient for evaluating the occurrence of reproductive effects following phthalate exposure in humans, based on existing relevant animal data. This is especially the case for data on female reproductive toxicity, which are scarce. Therefore, future research needs to focus on developmental and reproductive endpoints in humans. It should be noted that phthalates occur in mixtures but most toxicological information is based on single compounds. Thus, it is concluded that it is important to improve the knowledge of toxic interactions among the different chemicals and to develop measures for combined exposure to various groups of phthalates.

Iatrogenic environmental hazards in the neonatal intensive care unit

Premature infants in the neonatal intensive care unit (NICU) face many illnesses and complications. Another potential source of iatrogenic disease is the NICU environment. Research in this area, however, is limited.