A crossover-crossback prospective study of dibutyl-phthalate exposure from mesalamine medications and serum reproductive hormones in men

In Utero Exposure to Di-n-butyl Phthalate Causes Modulation in Neurotransmitter System of Wistar Rats: A Multigenerational Assessment

Neuroendocrine regulation is disrupted by di-n-butyl phthalate (DBP) when exposure occurs during the critical periods of fetal development, which can lead to neurological disorders. To evaluate the toxic potential of DBP, it is necessary to conduct teratological studies, which could determine impacts on the development of the fetus. The present study was designed to understand the sequelae of neuroendocrine regulation in one-month-old pups when rats were exposed to DBP (F1-F3) in utero and during lactation. The rats received DBP (500 mg/kg BW/day) dissolved in olive oil through oral gavage from gestation day 6 to postnatal day 30, while the control group received the olive oil (vehicle) during the same timeline. Following the exposure, thyroid profile and estradiol, which were measured at GD-19, exhibited a significant decrease (P < 0.05) in dams (F0-F2). The exposure resulted in developmental outcomes, including underdeveloped fetuses, and a notable number of resorptions in experimental rats. The one-month-old pups were assessed for serum thyroid profile and testosterone and neurotransmitters in discrete brain regions, cerebral cortex, cerebellum, and hippocampus for up to three generations. The levels of dopamine and cortisol showed a significant increase (P < 0.05), but serotonin levels decreased when examined in distinct brain regions of the experimental group as compared to the control. DBP, which is considered an endocrine disruptor, had the most impact on the third generation in this study, leading to a significant decrease in testosterone levels. In summary, in utero exposure to DBP impaired the neuroendocrine system and had an antiandrogenic effect in the three successive generations.

Inhibin B and antiMüllerian hormone as surrogate markers of fertility in male and female Crohn's disease patients: a case-control study

Background

Several studies suggest that women with Crohn disease (CD) have reduced fertility due to decreased ovarian reserve, among other causes. On the other hand, male CD patients could have difficulties conceiving. The present study aimed to test the effect of CD on both male and female fertility potential, Sertoli cell function and ovarian reserve, assessed by inhibin-B (IB) plus IB:FSH ratio (IFR) and antiMüllerian hormone (AMH), respectively. Sexual dysfunction (SD) was studied as secondary endpoint.

Methods

We performed a cross-sectional, case-control study. Serum IB levels plus IFR were measured in 58 men with CD and compared to 25 age-matched healthy controls (HC). Serum AMH levels were measured in 50 women with CD and in 30 HC matched by age. SD was assessed by means of the International Index of Erectile Function (IIFE-15) in males and the Index of Female Sexual Function (IFSF) in women.

Results

A total of 108 CD patients and 55 HC were included. IB serum levels were significantly lower in CD men than in HC (177 ± 58 vs. 234 ± 75 pg./mL, p = 0.001). IFR was also decreased in CD patients compared to HC (58.27 ± 59.5 vs. 91.35 ± 60.04, p = 0.014). Women with CD > 30 years had lower serum AMH levels compared to HC (1.15 ± 0.74 vs. 2.14 ± 1.68 ng/mL, p = 0.033). In addition, CD women >30 years presented a serum AMH < 2 ng/mL more frequently than HC (90% vs. 40%, p = 0.004). The prevalence of SD was significantly higher among both male and female CD patients compared to HC, without association to fertility potential. Age was the only predictor of low ovarian reserve.

Conclusion

Testicular Sertoli cell function assessed through serum IB levels and IFR is decreased in CD male patients compared to HC, regardless of age. Age > 30 years is the single independent predictor of reduced ovarian reserve in women with CD. These results should be confirmed in further studies in order to properly counsel patients with CD and desire for offspring.

Exposure to dibutyl phthalate adsorbed to multi-walled carbon nanotubes causes neurotoxicity in mice by inducing the release of BDNF

Multi-walled carbon nanotubes (MWCNTs) and dibutyl phthalate (DBP) exist extensively in the environment, and they are easy to form compound pollution through π-π interactions in the environment. We investigate whether DBP, an environmental hormone disruptor, mediated by CNTs can more easily cross the blood-brain barrier, and whether DBP entering the brain has neurotoxic effects on the cells in the brain. Experimental subjects were 40 male Kunming (KM) mice randomly divided into 4 groups: the control group; the MWCNTs group; the DBP group; and the MWCNTs+DBP group. The mice were exposed via tail intravenous injection once every 3 days for 21 days, following which toxicology studies were carried out. The results of behavioral experiments showed that the mice in the combined exposure group (MWCNTs+DBP) exhibited spatial learning and memory impairment, and anxiety-like behavior. Staining of hippocampal sections of mouse brain tissue showed that, in the CA1, CA2, and DG areas, the number of neurons decreased, the nucleus was pyknotic, the cell body was atrophied, and levels of the microglia marker Iba-1 increased. By proteomic KEGG analysis, we found that the DEPs were mainly those related to neurodegenerative diseases. Immunohistochemistry in the hippocampus indicated that the level of brain-derived neurotrophic factor (BDNF) in the DG region was significantly increased. RT-PCR results revealed that the expression levels of P53, caspase3, and Bax genes related to apoptosis were up-regulated. The experimental results demonstrated that the mechanism of the combined-exposure injury to neurons in the hippocampus of mice may be that MWCNTs with adsorbed DBP can induce the release of BDNF, accelerate the apoptosis of neurons, and reduce the number of nerve cells, which activates microglia, causing neuroinflammation and nervous system toxicity.

Reproductive toxicity of dibutyl phthalate adsorbed on carbon nanotubes in male Balb/C mice

Dibutyl phthalate (DBP) is an environmental hormone disrupter. This study was designed to investigate whether DBP adsorbed in multi-walled carbon nanotubes (MWCNTs) can easily cross the blood-testis barrier and slow down the degradation of DBP in male mice, thereby prolonging the interference effect of DBP. The results showed that: in male Balb/C mice, the sperm density of the MWCNTs group and the DBP plus MWCNTs group decreased significantly (p < 0.05); and the sperm deformity rate increased significantly (p < 0.05). Testicular tissue sections from the combined exposure group showed that most of the seminiferous tubules were atrophied, there were more large gaps between the cells in the tubules, and the number of mature-sperm decreased. The reactive oxygen species (ROS) levels increased significantly in the combined exposure group (p < 0.01). Proteomics results showed that there were 231 differentially expressed proteins in the combined exposure group compared with the MWCNTs only group, and 69 differentially expressed proteins compared with the DBP group. GO enrichment analysis showed that the differentially expressed proteins mainly include: 60s acid ribosomal protein P1; nuclear autoantigen sperm protein; centromere protein V; and other proteins related to cell division. These results indicate that MWCNTs with adsorbed DBP can increase oxidative damage in the testis of male mice, interfere with DNA replication and cell division in testicular tissue cells, induce cell apoptosis, and destroy the normal spermatogenic function of the testis.

Exposure to a combination of MWCNTs and DBP causes splenic toxicity in mice

The large conjugated π bond in the molecular structure of carbon nanotubes (CNTs) interacts with the benzene ring structure in di (n-butyl) phthalates (DBP) through a π - π bond. Compounds of CNTs and DBP form easily, becoming another environmental pollutant of concern. We explore whether CNTs entering animals slow down the degradation of the DBP adsorbed in the CNT cavity, thereby prolonging the "hormonal activity" of DBP. In our study, male BALb/c mice were used as experimental subjects divided into four groups: the control group; the multi-walled carbon nanotubes (MWCNTs) exposure group (10mg/kg/d); the DBP exposure group (2.15 mg/kg/d); and the compound exposure group (MWCNTs + DBP). After 30 days of exposure, the mice were sacrificed and their spleens used for immunotoxicology study. The results showed that the exposure groups exhibited splenomegaly and suffered severe oxidative damage to the spleen. In the compound exposure group: levels of IgA and IgG in the serum of the mice changed, and were significantly different from levels in both the MWCNTs and DBP exposure groups (p <0.05); the pathological sections of the spleen showed that the boundary between the white pulp area (WP) and the red pulp area (RP) was blurred, that the cell arrangement was loose, and that more red blood cells were retained in the spleen. Proteomics mass spectrometry analysis showed that compared with the control group, 70 proteins were up-regulated and 27 proteins were down-regulated in the MWCNTs group, 36 proteins were up-regulated and 23 proteins were down-regulated in the DBP group, 87 proteins were up-regulated and 21 proteins were down-regulated in the compound exposure group. The results of GO enrichment analysis and KEGG enrichment analysis of the differentially expressed proteins showed that the compound exposure harmed the spleen antigen recognition, processing, and presentation, inhibited the activation and proliferation of B cells and T cells, and hindered the adaptive immune responses. Our results showed that MWCNTs and DBP compounds can damage the spleen, and impair the innate and adaptive immune functions of the body.

Associations between medication use and phthalate metabolites in urine and follicular fluid among women undergoing in vitro fertilization

BACKGROUND

Phthalates, which are used as excipients of drugs, have been related to adverse reproductive outcomes. However, the relationships between medication use and phthalate exposure among women undergoing in vitro fertilization (IVF) have not been studied.

OBJECTIVE

To investigate the associations between the medication intake and phthalate metabolites in urine and follicular fluid (FF).

METHOD

Eight phthalate metabolites were measured in urine and FF samples from 274 women undergoing IVF using liquid chromatography-tandem mass spectrometry. Information on recent medication intake was obtained via interview by trained staff. We constructed generalized linear regression models to examine the associations of medication intake with phthalate metabolite concentrations and dose-response relationships between the number of medicines used and metabolite concentrations in two matrices.

RESULTS

Four of 10 drugs were used by more than 10% of the participants, including vitamins (23.0%), traditional Chinese medicine (TCM, 22.3%), antioxidants (12.4%) and amoxicillin (10.2%). Participants who had used TCM had 26.0% (95% CI: 0.0, 58.8%), 32.6% (95% CI: 4.2, 68.8%) and 32.3% (95% CI: 2.6, 70.6%) higher urinary mono-n-butyl phthalate (MBP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP) concentrations, respectively, than those who had not. Antioxidant intake was associated with a 30.6% (95% CI: -48.5, -6.6%) decrease in the urinary MBP concentration. Compared with non-users, women who reported the use of medicines had 53.2% (95% CI: 2.7, 128.5%) higher concentrations of MMP and a 37.7% (95% CI: -60.7, -1.5%) lower level of MBP in FF, respectively.

CONCLUSION

Our data suggest that the intake of some medications may increase phthalate exposure among women undergoing IVF.

Phthalate and BPA Exposure in Women and Newborns through Personal Care Product Use and Food Packaging

Phthalates and bisphenol A (BPA) are used in some personal care products (PCPs) and containers for food processing and packaging. The Plastics and Personal-Care Product use in Pregnancy (P4) Study (2009-10) explored the association between PCP use during pregnancy and the postpartum period among 80 pregnant women and 55 infants and BPA and phthalate concentrations in multiple maternal and infant urine specimens collected throughout the study (n = 1260 samples). The type, frequency, and timing of PCP and food packaging use 24 h before and during the urine collection period was collected at 5 time points for the mother using prospective diaries. Infant urine was collected up to 2 times before 3 months of age, and mothers answered questions about infant feeding and PCP use on their baby. In mothers, monoethyl phthalate (MEP) metabolite concentrations were significantly higher when women reported using makeup or body lotion in the last 24 h. MEP concentrations were consistently higher when the usage occurred within 0-6 h before the urine sample collection for almost all of the PCP categories. Infant lotion or baby powder application in the previous 24 h was associated with higher phthalate metabolite concentrations in infants. Total BPA metabolite concentrations were lower in exclusively breastfed infants compared to those who were exclusively formula fed or breastfed with supplementation. Given that PCPs tend to undergo frequent formulation changes, which could impact the relative importance of a certain product type as a source of exposure, continued research of this type is warranted.

The effects of di-butyl phthalate exposure from medications on human sperm RNA among men

Endocrine disruptors, such as phthalates, are suspected of affecting reproductive function. The Mesalamine and Reproductive Health Study (MARS) was designed to address the physiological effect of in vivo phthalate exposure on male reproduction in patients with Inflammatory Bowel Disease (IBD). As part of this effort, the effect on sperm RNAs to DBP exposure were longitudinally assessed using a cross-over cross-back binary design of high or background, exposures to DBP. As the DBP level was altered, numerous sperm RNA elements (REs) were differentially expressed, suggesting that exposure to or removal from high DBP produces effects that require longer than one spermatogenic cycle to resolve. In comparison, small RNAs were minimally affected by DBP exposure. While initial study medication (high or background) implicates different biological pathways, initiation on the high-DBP condition activated oxidative stress and DNA damage pathways. The negative correlation of REs with specific genomic repeats suggests a regulatory role. Using ejaculated sperm, this work provides insight into the male germline's response to phthalate exposure.

A strategy to validate a selection of human effect biomarkers using adverse outcome pathways: Proof of concept for phthalates and reproductive effects

Human biomonitoring measures the concentrations of environmental chemicals or their metabolites in body fluids or tissues. Complementing exposure biomarkers with mechanistically based effect biomarkers may further elucidate causal pathways between chemical exposure and adverse health outcomes. We combined information on effect biomarkers previously implemented in human observational studies with mechanisms of action reported in experimental studies and with information from published Adverse Outcome Pathways (AOPs), focusing on adverse reproductive effects of phthalate exposure. Phthalates constitute a group of chemicals that are ubiquitous in consumer products and have been related to a wide range of adverse health effects. As a result of a comprehensive literature search, we present an overview of effect biomarkers for reproductive toxicity that are substantiated by mechanistic information. The activation of several receptors, such as PPARα, PPARγ, and GR, may initiate events leading to impaired male and female fertility as well as other adverse effects of phthalate exposure. Therefore, these receptors appear as promising targets for the development of novel effect biomarkers. The proposed strategy connects the fields of epidemiology and toxicology and may strengthen the weight of evidence in observational studies that link chemical exposures to health outcomes.

High phthalate exposure increased urinary concentrations of quinolinic acid, implicated in the pathogenesis of neurological disorders: Is this a potential missing link?

BACKGROUND

Quinolinic acid (QA), a neuroactive metabolite of the Kynurenine Pathway (KP), is an excitotoxin that is implicated in the pathogenesis of many neurological disorders. KP is the main tryptophan degradation pathway. Phthalates can structurally mimic tryptophan metabolites and diets containing phthalates in rats enhanced the production and excretion of QA. However, there are no human studies that have examined the association between phthalates and QA.

OBJECTIVES

Taking advantage of different mesalamine formulations with/without dibutyl phthalate (DBP), we assessed whether DBP from mesalamine (>1000x background) altered the urinary concentrations of QA.

METHODS

Men with inflammatory bowel disease participated in a prospective crossover pilot study. 15 Men were on non-DBP mesalamine (background) at baseline crossed-over for 4 months to high-DBP mesalamine (high) (B1H-Arm) and vice versa for 15 men who were on high-DBP mesalamine at baseline (H1B-Arm). Men provided 60 urine samples (2/man). We estimated crossover and cross-sectional changes in the creatinine normalized-QA using multivariable linear mixed effect models with random intercepts.

RESULTS

At baseline, men who were on high-DBP mesalamine (H1B-Arm) had 72%, (95% confidence interval (CI): 18, 151) higher normalized-QA than men who were on background exposure and when high-DBP mesalamine was removed for four months, normalized-QA decreased with 32%, (95% CI: -45.0, -15.1). Consistently, when men in B1H-Arm were newly-exposed to high-DBP mesalamine, normalized-QA increased with 11%, (95% CI: -11, 38).

CONCLUSIONS

High-DBP exposure from mesalamine increased the urinary concentrations of QA, which was largely reversed after removal of the high-DBP exposure for four months. This novel hypothesis should warrant new promising research considering the KP and QA concentrations as a plausible mediator for the neurotoxicity possibly linked with phthalate exposures.

Temporal Trends of Urinary Phthalate Concentrations in Two Populations: Effects of REACH Authorization after Five Years

Phthalates are widely used in the industrial manufacture of many products. Some phthalates have shown reproductive toxicity in humans, acting as endocrine disruptors, so they were included in the authorization process defined in Reg. CE 1907/2006 (REACH). Two groups of population were recruited, before and after the inclusion of some phthalates in the authorization list in REACH: the first group of 157 volunteers was studied in 2011 and the second, 171 volunteers, in 2016. Each subject completed a questionnaire about personal lifestyle, working activities and use of chemical products. The main urinary metabolites of five phthalates were analyzed by HPLC/MS/MS: mono(2-ethylhexyl)phthalate (MEHP) and mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) for di(2-ethylhexyl)phthalate (DEHP) exposure; monoethylphthalate (MEP) for diethylphtahate (DEP); monobenzylphthalate (MBzP) for butylbenzylphtahalate (BBP) and dibenzylphthalate (DBzP), mono-n-butylphthalate (MnBP) for butylbenzylphtahalate (BBP) and di-n-butylphthalate (DnBP). The results show a significant difference for all metabolites between the two periods, with the exception of MEP in women. The comparison of the two sets of results shows a decrease in urinary metabolites excretion from 2011 to 2016, statistically significant for the three phthalates included in Annex XIV of REACH. DEP, not currently included in the list for authorization, maintains a constant presence in the daily life of the population, particularly for women.

Dibutyl-phthalate exposure from mesalamine medications and serum thyroid hormones in men

BACKGROUND

Dibutyl phthalate (DBP) is an endocrine disruptor and used in some medication coatings, such as mesalamine for treatment inflammatory bowel disease (IBD).

OBJECTIVES

To determine whether high-DBP from some mesalamine medications alters thyroid function.

METHODS

Seventy men with IBD, without thyroid disease or any radiation history participated in a crossover-crossback prospective study and provided up to 6 serum samples (2:baseline, 2:crossover, 2:crossback). Men on non-DBP mesalamine (background exposure) at baseline crossed-over to DBP-mesalamine (high exposure) then crossed-back to non-DBP mesalamine (B₁HB₂-arm) and vice versa for men on DBP-mesalamine at baseline (H₁BH₂-arm). Serum concentrations of total triiodothyronine (T3), total thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH) and thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb).

RESULTS

After crossover in B₁HB₂-arm (26 men, 134 samples), T3 decreased 10% (95% confidence interval (CI): 14%,-5%), T3/T4 ratio decreased 8% (CI: 12%,-3%), TPOAb, and TgAb concentrations decreased, 11% (-20%, -2%) and 15% (-23%, -5%), respectively; after crossback, they increased. When men in the H₁BH₂-arm (44 men, 193 samples) crossed-over, T3 decreased 7% (CI: -11%, -2%) and T3/T4 ratio decreased 6% (CI: -9%, -2%). After crossback, only TgAb increased and FT4 decreased.

CONCLUSIONS

High-DBP novel exposure or removal from chronic high-DBP exposure could alter elements of the thyroid system, and most probably alters the peripheral T4 conversion to T3 and thyroid autoimmunity, consistent with thyroid disruption. After exposure removal, these trends were mostly reversed.

Environmental Toxins and Male Fertility

PURPOSE OF REVIEW

Global industrialization has increased population exposure to environmental toxins. A global decline in sperm quality over the last few decades raises questions about the adverse impact of environmental toxins on male reproductive health.

RECENT FINDINGS

Multiple animal- and human-based studies on exposure to environmental toxins suggest a negative impact on semen quality, in terms of sperm concentration, motility, and/or morphology. These toxins may exert estrogenic and/or anti-androgenic effects, which in turn alter the hypothalamic-pituitary-gonadal axis (HPGA), induce sperm DNA damage, or cause sperm epigenetic changes. This chapter will discuss the most recent literature about the most common environmental toxins and their impact on spermatogenesis and its consequences on male fertility. Understanding the presence and underlying mechanism of these toxins will help us preserve the integrity of the male reproduction system and formulate better regulations against their indiscriminate use.