Maternal exposure to di-n-butyl phthalate (DBP) induces renal fibrosis in adult rat offspring

Prenatal exposure to dibutyl phthalate contributes to erectile dysfunction in offspring male rats by activating the RhoA/ROCK signalling pathway

Prenatal exposure to dibutyl phthalate (DBP) has been reported to cause erectile dysfunction (ED) in adult offspring rats. However, its underlying mechanisms are not fully understood. Previously, we found that DBP activates the RhoA/ROCK pathway in the male reproductive system. This study investigated how prenatal exposure to DBP activates the RhoA/ROCK signalling pathway, leading to ED in male rat offspring. Pregnant rats were stratified into DBP-exposed and NC groups, with the exposed group receiving 750 milligrams per kilogram per day (mg/kg/day) of DBP through gavage from days 14-18 of gestation. DBP exposure activated the RhoA/ROCK pathway in the penile corpus cavernosum (CC) of descendants, causing smooth muscle cell contraction, fibrosis, and apoptosis, all of which contribute to ED. In vitro experiments confirmed that DBP induces apoptosis and RhoA/ROCK pathway activation in CC smooth muscle cells. Treatment of DBP-exposed offspring with the ROCK inhibitor Y-27632 for 8 weeks significantly improved smooth muscle cell condition, erectile function, and reduced fibrosis. Thus, prenatal DBP exposure induces ED in offspring through RhoA/ROCK pathway activation, and the ROCK inhibitor Y-27632 shows potential as an effective treatment for DBP-induced ED.

Nutritional Approaches Targeting Gut Microbiota in Oxidative-Stress-Associated Metabolic Syndrome: Focus on Early Life Programming

Metabolic syndrome (MetS) denotes a constellation of risk factors associated with the development of cardiovascular disease, with its roots potentially traced back to early life. Given the pivotal role of oxidative stress and dysbiotic gut microbiota in MetS pathogenesis, comprehending their influence on MetS programming is crucial. Targeting these mechanisms during the early stages of life presents a promising avenue for preventing MetS later in life. This article begins by examining detrimental insults during early life that impact fetal programming, ultimately contributing to MetS in adulthood. Following that, we explore the role of oxidative stress and the dysregulation of gut microbiota in the initiation of MetS programming. The review also consolidates existing evidence on how gut-microbiota-targeted interventions can thwart oxidative-stress-associated MetS programming, encompassing approaches such as probiotics, prebiotics, postbiotics, and the modulation of bacterial metabolites. While animal studies demonstrate the favorable effects of gut-microbiota-targeted therapy in mitigating MetS programming, further clinical investigations are imperative to enhance our understanding of manipulating gut microbiota and oxidative stress for the prevention of MetS.

Exposure to the plasticizer diisopentyl phthalate can cause Vero cell line death

Phthalates are synthetic plasticizers present in the daily lives of humans, as part of the composition of different products, such as food packaging, water bottles, and toys. These compounds can migrate from plastic materials to the environment changing biological systems. Although diisopentyl phthalate (DiPeP) is largely used in Brazil, there is a lack of information on the possible toxic effects of this compound. This research aims to evaluate the toxicity of DiPeP in the Vero renal cells. These cells were exposed to the 1-1000 μM of DiPeP for 24 and 72 h and subsequently, the cytotoxicity, apoptosis and necrosis-inducing potential, and antioxidant system (SOD, GPx, and GST) were investigated. DiPeP neither caused cytotoxicity nor altered SOD and GPx activity, although GST has been increased at 100 or 1 μM (24 and 72 h, respectively). However, cell death by apoptosis and necrosis was observed. These results indicate that DiPeP caused cell death by a non-oxidative stress-mediated mechanism, which shows the relevance of investigate other process in further researches.

Melatonin Use during Pregnancy and Lactation Complicated by Oxidative Stress: Focus on Offspring's Cardiovascular-Kidney-Metabolic Health in Animal Models

Cardiovascular-kidney-metabolic (CKM) syndrome has emerged as a major global public health concern, posing a substantial threat to human health. Early-life exposure to oxidative stress may heighten vulnerability to the developmental programming of adult diseases, encompassing various aspects of CKM syndrome. Conversely, the initiation of adverse programming processes can potentially be thwarted through early-life antioxidant interventions. Melatonin, originally recognized for its antioxidant properties, is an endogenous hormone with diverse biological functions. While melatonin has demonstrated benefits in addressing disorders linked to oxidative stress, there has been comparatively less focus on investigating its reprogramming effects on CKM syndrome. This review consolidates the current knowledge on the role of oxidative stress during pregnancy and lactation in inducing CKM traits in offspring, emphasizing the underlying mechanisms. The multifaceted role of melatonin in regulating oxidative stress, mediating fetal programming, and preventing adverse outcomes in offspring positions it as a promising reprogramming strategy. Currently, there is a lack of sufficient information in humans, and the available evidence primarily originates from animal studies. This opens up new avenues for novel preventive intervention in CKM syndrome.

Prenatal to peripubertal exposure to Di(2-ethylhexyl) phthalate induced endometrial atrophy and fibrosis in female mice

Di(2-ethylhexy) phthalate (DEHP) is a widely used plasticizer that is ubiquitously found in the environment. Using a mouse model, we investigated the impact of early life DEHP exposure ranging from the prenatal to peripubertal developmental period of the female reproductive system. Pregnant female mice were allocated to three groups as follows: control, 100 mg/kg/day, and 500 mg/kg/day DEHP treatment. DEHP exposure was introduced through feeding during pregnancy (3 weeks) and lactation (3 weeks). After weaning, the offspring were also exposed to DEHP through feeding for another 2 weeks. Observations were conducted on female offspring at 10 and 24 weeks. The number of live offspring per dam was significantly lower in the high-DEHP-exposed group (500 mg/kg/day) compared to the control group (7.67 ± 1.24 vs. 14.17 ± 0.31; p < 0.05) despite no difference in pregnancy rates across the groups. Low-DEHP exposure (100 mg/kg/day) resulted to a decreased body weight (36.07 ± 3.78 vs. 50.11 ± 2.11 g; p < 0.05) and decreased left uterine length (10.60 ± 1.34 vs. 14.77 ± 0.82 mm; p < 0.05) in 24-week- old female mice. As early as 10 weeks, endometrial atrophy and fibrosis were observed, and endometrial cystic hyperplasia was noted in female mice at 24 weeks. Our study is the first to demonstrate that female mice exposed to DEHP in the early life developed endometrial fibrosis in the female offspring. Further studies on the consequences of these observations in fecundity and other reproductive functions are warranted.

TGFβ signaling links early life endocrine-disrupting chemicals exposure to suppression of nucleotide excision repair in rat myometrial stem cells

Environmental exposure to endocrine-disrupting chemicals (EDCs) is linked to the development of uterine fibroids (UFs) in women. UFs, non-cancerous tumors, are thought to originate from abnormal myometrial stem cells (MMSCs). Defective DNA repair capacity may contribute to the emergence of mutations that promote tumor growth. The multifunctional cytokine TGFβ1 is associated with UF progression and DNA damage repair pathways. To investigate the impact of EDC exposure on TGFβ1 and nucleotide excision repair (NER) pathways, we isolated MMSCs from 5-month-old Eker rats exposed neonatally to diethylstilbestrol (DES), an EDC, or to vehicle (VEH). EDC-MMSCs exhibited overactivated TGFβ1 signaling and reduced mRNA and protein levels of NER pathway components compared to VEH-MMSCs. EDC-MMSCs also demonstrated impaired NER capacity. Exposing VEH-MMSCs to TGFβ1 decreased NER capacity while inhibiting TGFβ signaling in EDC-MMSCs restored it. RNA-seq analysis and further validation revealed decreased expression of Uvrag, a tumor suppressor gene involved in DNA damage recognition, in VEH-MMSCs treated with TGFβ1, but increased expression in EDC-MMSCs after TGFβ signaling inhibition. Overall, we demonstrated that the overactivation of the TGFβ pathway links early life exposure to EDCs with impaired NER capacity, which would lead to increased genetic instability, arise of mutations, and fibroid tumorigenesis. We demonstrated that the overactivation of the TGFβ pathway links early life exposure to EDCs with impaired NER capacity, which would lead to increased fibroid incidence.

TGFβ signaling links early-life endocrine-disrupting chemicals exposure to suppression of nucleotide excision repair in rat myometrial stem cells

Environmental exposure to endocrine-disrupting chemicals (EDCs) is linked to the development of uterine fibroids (UFs) in women. UFs, non-cancerous tumors, are thought to originate from abnormal myometrial stem cells (MMSCs). Defective DNA repair capacity may contribute to the emergence of mutations that promote tumor growth. The multifunctional cytokine TGFβ1 is associated with UF progression and DNA damage repair pathways. To investigate the impact of EDC exposure on TGFβ1 and nucleotide excision repair (NER) pathways, we isolated MMSCs from 5-months old Eker rats exposed neonatally to Diethylstilbestrol (DES), an EDC, or to vehicle (VEH). EDC-MMSCs exhibited overactivated TGFβ1 signaling and reduced mRNA and protein levels of NER pathway components compared to VEH-MMSCs. EDC-MMSCs also demonstrated impaired NER capacity. Exposing VEH-MMSCs to TGFβ1 decreased NER capacity while inhibiting TGFβ signaling in EDC-MMSCs restored it. RNA-seq analysis and further validation revealed decreased expression of Uvrag, a tumor suppressor gene involved in DNA damage recognition, in VEH-MMSCs treated with TGFβ1, but increased expression in EDC-MMSCs after TGFβ signaling inhibition. Overall, we demonstrated that the overactivation of the TGFβ pathway links early-life exposure to EDCs with impaired NER capacity, which would lead to increased genetic instability, arise of mutations, and fibroid tumorigenesis. We demonstrated that the overactivation of the TGFβ pathway links early-life exposure to EDCs with impaired NER capacity, which would lead to increased fibroid incidence.

DBP and BaP co-exposure induces kidney injury via promoting pyroptosis of renal tubular epithelial cells in rats

Dibutyl phthalate (DBP) and benzo(a)pyrene (BaP) are widespread environmental and foodborne contaminants that have detrimental effects on human health. Although people are often simultaneously exposed to DBP and BaP via the intake of polluted food and water, the combined effects on the kidney and potential mechanisms remain unclear. Hence, we treated rats with DBP and BaP for 90 days to investigate their effects on kidney histopathology and function. We also investigated the levels of paramount proteins and genes involved in pyroptosis and TLR4/NF-κB p65 signaling in the kidney. Our research showed that combined exposure to DBP and BaP triggered more severe histopathological and renal function abnormalities than in those exposed to DBP or BaP alone. Simultaneously, combined exposure to DBP and BaP enhanced the excretion of IL-1β and IL-18, along with the release of LDH in rat renal tubular epithelial cells (RTECs). Moreover, combined exposure to DBP and BaP increased the expression of pyroptosis marker molecules, including NLRP3, ASC, cleaved-Caspase-1, and GSDMD. Meanwhile, the combination of DBP and BaP activated TLR4/NF-κB signaling in the kidney. Taken together, the combined exposure to DBP and BaP causes more severe kidney injury than that caused by DBP or BaP exposure separately. In addition, pyroptosis of RTECs regulated by TLR4/NF-κB signaling may add to the kidney damage triggered by combined exposure to DBP and BaP.

Perinatal Oxidative Stress and Kidney Health: Bridging the Gap between Animal Models and Clinical Reality

Oxidative stress arises when the generation of reactive oxygen species or reactive nitrogen species overwhelms antioxidant systems. Developing kidneys are vulnerable to oxidative stress, resulting in adult kidney disease. Oxidative stress in fetuses and neonates can be evaluated by assessing various biomarkers. Using animal models, our knowledge of oxidative-stress-related renal programming, the molecular mechanisms underlying renal programming, and preventive interventions to avert kidney disease has grown enormously. This comprehensive review provides an overview of the impact of perinatal oxidative stress on renal programming, the implications of antioxidant strategies on the prevention of kidney disease, and the gap between animal models and clinical reality.

Metabolic Syndrome Programming and Reprogramming: Mechanistic Aspects of Oxidative Stress

Metabolic syndrome (MetS) is a worldwide public health issue characterized by a set of risk factors for cardiovascular disease. MetS can originate in early life by developmental programming. Increasing evidence suggests that oxidative stress, which is characterized as an imbalance between reactive oxygen species (ROS), nitric oxide (NO), and antioxidant systems, plays a decisive role in MetS programming. Results from human and animal studies indicate that maternal-derived insults induce MetS later in life, accompanied by oxidative stress programming of various organ systems. On the contrary, perinatal use of antioxidants can offset oxidative stress and thereby prevent MetS traits in adult offspring. This review provides an overview of current knowledge about the core mechanisms behind MetS programming, with particular focus on the occurrence of oxidative-stress-related pathogenesis as well as the use of potential oxidative-stress-targeted interventions as a reprogramming strategy to avert MetS of developmental origins. Future clinical studies should provide important proof of concept for the effectiveness of these reprogramming interventions to prevent a MetS epidemic.

Oxidative Stress-Induced Hypertension of Developmental Origins: Preventive Aspects of Antioxidant Therapy

Hypertension remains the leading cause of disease burden worldwide. Hypertension can originate in the early stages of life. A growing body of evidence suggests that oxidative stress, which is characterized as a reactive oxygen species (ROS)/nitric oxide (NO) disequilibrium, has a pivotal role in the hypertension of developmental origins. Results from animal studies support the idea that early-life oxidative stress causes developmental programming in prime blood pressure (BP)-controlled organs such as the brain, kidneys, heart, and blood vessels, leading to hypertension in adult offspring. Conversely, perinatal use of antioxidants can counteract oxidative stress and therefore lower BP. This review discusses the interaction between oxidative stress and developmental programming in hypertension. It will also discuss evidence from animal models, how oxidative stress connects with other core mechanisms, and the potential of antioxidant therapy as a novel preventive strategy to prevent the hypertension of developmental origins.

Educational Review: The Impact of Perinatal Oxidative Stress on the Developing Kidney

Oxidative stress occurs when there is an imbalance between reactive oxygen species/reactive nitrogen species and antioxidant systems. The interplay between these complex processes is crucial for normal pregnancy and fetal development; however, when oxidative stress predominates, pregnancy related complications and adverse fetal programming such as preterm birth ensues. Understanding how oxidative stress negatively impacts outcomes for the maternal-fetal dyad has allowed for the exploration of antioxidant therapies to prevent and/or mitigate disease progression. In the developing kidney, the negative impact of oxidative stress has also been noted as it relates to the development of hypertension and kidney injury mostly in animal models. Clinical research addressing the implications of oxidative stress in the developing kidney is less developed than that of the neurodevelopmental and respiratory conditions of preterm infants and other vulnerable neonatal groups. Efforts to study the oxidative stress pathway along the continuum of the perinatal period using a team science approach can help to understand the multi-organ dysfunction that the maternal-fetal dyad sustains and guide the investigation of antioxidant therapies to ameliorate the global toxicity. This educational review will provide a comprehensive and multidisciplinary perspective on the impact of oxidative stress during the perinatal period in the development of maternal and fetal/neonatal complications, and implications on developmental programming of accelerated aging and cardiovascular and renal disease for a lifetime.

Developmental Origins of Kidney Disease: Why Oxidative Stress Matters?

The "developmental origins of health and disease" theory indicates that many adult-onset diseases can originate in the earliest stages of life. The developing kidney has emerged as being particularly vulnerable to adverse in utero conditions leading to morphological and functional changes, namely renal programming. Emerging evidence indicates oxidative stress, an imbalance between reactive oxygen/nitrogen species (ROS/RNS) and antioxidant systems, plays a pathogenetic role in the developmental programming of kidney disease. Conversely, perinatal use of antioxidants has been implemented to reverse programming processes and prevent adult-onset diseases. We have termed this reprogramming. The focus of this review is twofold: (1) To summarize the current knowledge on oxidative stress implicated in renal programming and kidney disease of developmental origins; and (2) to provide an overview of reprogramming effects of perinatal antioxidant therapy on renal programming and how this may prevent adult-onset kidney disease. Although early-life oxidative stress is implicated in mediating renal programming and adverse offspring renal outcomes, and animal models provide promising results to allow perinatal antioxidants applied as potential reprogramming interventions, it is still awaiting clinical translation. This presents exciting new challenges and areas for future research.

Effects and Mechanisms of Phthalates' Action on Reproductive Processes and Reproductive Health: A Literature Review

The production of plastic products, which requires phthalate plasticizers, has resulted in the problems for human health, especially that of reproductive health. Phthalate exposure can induce reproductive disorders at various regulatory levels. The aim of this review was to compile the evidence concerning the association between phthalates and reproductive diseases, phthalates-induced reproductive disorders, and their possible endocrine and intracellular mechanisms. Phthalates may induce alterations in puberty, the development of testicular dysgenesis syndrome, cancer, and fertility disorders in both males and females. At the hormonal level, phthalates can modify the release of hypothalamic, pituitary, and peripheral hormones. At the intracellular level, phthalates can interfere with nuclear receptors, membrane receptors, intracellular signaling pathways, and modulate gene expression associated with reproduction. To understand and to treat the adverse effects of phthalates on human health, it is essential to expand the current knowledge concerning their mechanism of action in the organism.

Activation of the RhoA/ROCK pathway contributes to renal fibrosis in offspring rats induced by maternal exposure to di-n-butyl phthalate

Maternal exposure to di-n-butyl phthalate (DBP) can cause renal fibrosis in adult offspring rats. However, its underlying mechanisms have not yet been fully understood. In this study, we investigated whether the RhoA/ROCK pathway plays an important role in offspring renal fibrosis induced by maternal exposure to DBP. Our results showed that maternal exposure to DBP (850 mg/kg/day orally feeding during gestational days 14-18) activated the RhoA/ROCK pathway and induced epithelial-mesenchymal transition (EMT) in kidneys of offspring rats. Compared with the control group treated with normal saline, EMT in the kidneys of offspring rats undergoing 8 weeks of ROCK inhibitor Y-27632 treatment (at a dose of 30 mg/kg) was significantly inhibited, the degree of renal fibrosis was significantly reduced, and the renal function was significantly improved. DBP (10 μmol/L) activated the RhoA/ROCK pathway and induced EMT in NRK-52E cells in vitro. Both 5 μM and 10 μM Y-27632, a ROCK inhibitor, significantly reduced the EMT of NRK-52E cells. Taken together, our findings suggest that the RhoA/ROCK pathway plays an important role in the pathogenesis of renal fibrosis in offspring rats induced by maternal exposure to DBP via promoting EMT of renal tubular epithelial cells.

In utero di-n-butyl phthalate exposure induced abnormal autophagy in renal tubular cells via hedgehog signaling in newborn rats

Di-n-butyl phthalate (DBP) is a pollutant that is widely present in the environment. We have previously demonstrated that maternal exposure to DBP resulted in renal fibrosis in offspring, but the underlying mechanism was not well elucidated. Therefore, the current study aims to understand the underlying molecular mechanisms in these sex-specific developmental alterations. Here, we used RNA-seq analysis to explore the underlying molecular mechanisms of DBP-associated renal fibrosis. Pregnant rats received DBP orally at a dose of 850 mg/kg BW/day during gestational days 14-18. Upregulated autophagy in renal tubules in offspring was confirmed in the DBP-treated group via accessing LC3Ⅱ/Ⅰ protein expression. Increased expression of the HhIP gene was found in the DBP-treated group via RNA-seq analysis. Immunohistochemistry (IHC) staining and Western blot analysis confirmed increased expression of HhIP protein and inhibited hedgehog signaling. Increased HhIP expression further leaded to impaired activation of hedgehog signaling, which is critical for normal embryonic development. Additional in vitro experiments on renal tubular cells suggest that inactivation of hedgehog signaling induced autophagy in renal tubular cells. Taken together, our findings show that maternal exposure to DBP induced autophagy through regulation of hedgehog signaling via overexpression of HhIP in foetal renal tubular cells, which may be essential for renal fibrosis development.

Di-n-butyl phthalate (DBP) reduces epithelial-mesenchymal transition via IP3R in hypospadias during maternal exposure

OBJECTIVE

This study focused on the oxidative stress effect of di-n-butyl phthalate (DBP) on development of the urinary system.

METHODS

We examined the mRNA expression of genital tubercle (GT) in control and DBP induced hypospadias group by Affymetrix Rat 230 2.0 Array. Real-time PCR and Western Blot were used to detect the protein and mRNA expression levels of inositol-1,4,5-triphate-receptor (IP3R) and epithelial-mesenchymal-transition (EMT)-related molecular markers, such as E-cadherin, β-Catenin, Snail, N-cadherin, in the GT of hypospadiac male rats and controls. The results of array were further confirmed in vitro. The changes of intracellular calcium concentration in urethral epithelial cells were detected by Fluo-3-AM before and after DBP treatment. The levels of reactive oxygen species (ROS) in urethral epithelial cells were measured by DCFH-DA with different concentrations of DBP (0, 1, 10, 100 μmol/L) treatment.

RESULTS

The mRNA expression profiles of GT in control and DBP induced hypospadias group showed high expression of IP3R and the abnormalities of EMT. Compared to the control group, the expression levels of IP3R, E-cadherin and β-Catenin increased at both the protein and mRNA levels. However the expression levels of Snail and N-cadherin decreased. The intracellular calcium concentration increased significantly after DBP treatment. The effect of DBP on urethral epithelial cells was linked to the generation of oxidative stress.

CONCLUSION

DBP can influence the development of GT through its oxidative stress effect, which significantly increases the concentration of calcium and inhibits EMT in urethral epithelial cells, and block the fusion process of urethral groove, causing the occurrence of hypospadias. This study provides a new understanding of DBP's molecular mechanisms on hypospadias and may lead to new treatment strategies for the disease.

Maternal exposure to di-n-butyl phthalate promotes Snail1-mediated epithelial-mesenchymal transition of renal tubular epithelial cells via upregulation of TGF-β1 during renal fibrosis in rat offspring

We previously demonstrated that maternal exposure to di-n-butyl phthalate (DBP) resulted in renal fibrosis in male offspring; however, the underlying mechanism governing this effect has not been thoroughly elucidated to date. We hypothesized that DBP exposure induces TGF-β expression and abnormal activation of epithelial-mesenchymal transition (EMT) in fibrotic kidneys. Pregnant rats received DBP orally at a dose of 850 mg/kg BW/day during gestational days 14-18. In the DBP-exposed group, immunohistochemistry (IHC) staining showed increased expression of TGF-β1 and EMT markers. In rat kidney tubular epithelial cells (NRK52E), ROS production increased expression levels of TGF-β1 and subsequently contributed to the induction of Snail1-mediated EMT. Notably, DBP exposure also promoted autophagy that downregulated TGF-β1. Taken together, our findings suggest that maternal exposure to DBP promotes EMT in tubular epithelial cells via upregulation of TGF-β1.

Neurochemical alterations following the exposure to di-n-butyl phthalate in rats

Due to its ability to cross blood brain barrier and placenta, dibutyl phthalate (di-n-butyl phthalate, DBP) is expected to cause severe side effects to the central nervous system of animals and humans. A little data is available about the potential DBP neurotoxicity; therefore, this work was designed to investigate the brain tissue injury induced by DBP exposure. Forty Wister albino rats were allocated randomly into 4 groups (10 rats each). Group 1 served as control and the rats administered with physiological saline (0.9% NaCl) orally for 12 weeks. Groups 2, 3 and 4 were orally treated with DPB (100, 250 and 500 mg/kg) respectively for 12 weeks. DBP-intoxicated rats showed a disturbance in the oxidative status in cerebral cortex, striatum and brainstem, as represented by the elevated oxidants [malondialdehyde (MDA), nitric oxide (NO), 8-hydroxy-2-deoxyguanosine (8-OHdG)] and the decreased antioxidant molecules [reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR)]. DBP also enhanced a pro-inflammatory state through increasing the release of tumor necrosis factor- α (TNF-α) and interleukin-1β (IL-1β). The increase of these cytokines was associated with the increase of pro-apoptotic proteins [Bcl-2 associated X protein (Bax) and caspase-3] and the decrease of the anti-apoptotic protein, B cell lymphoma 2 (Bcl-2). In addition, the levels of norepinephrine (NE), dopamine (DA) and acetylcholine esterase (AChE) activity were decreased. This was accompanied by the alterations in the major excitatory and inhibitory amino acids neurotransmitters levels. The present findings indicated that DBP could exert its neuronal damage through oxidative stress, DNA oxidation, neuroinflammation, activation of apoptotic proteins and altering the monoaminergic, cholinergic and amino acids transmission.

Association between urinary concentration of phthalate metabolites and impaired renal function in Shanghai adults

BACKGROUND

Exposure to phthalates is reported to be associated with increased incidence of microalbuminuria and low-grade albuminuria in children and adolescents. However, this phenomenon of phthalate-related nephrotoxicity is unknown in adults.

METHODS

Urine samples of 1663 adults from the 2012 Shanghai Food Consumption Survey (SHFCS) were measured for 10 metabolites of 6 phthalates and for renal function parameters. Their associations were explored by linear and logistic regression models.

RESULTS

Multivariate linear regression analysis showed that all three renal function parameters (albumin-to-creatinine ratio (ACR), β2-microglobulin (B2M), and N-acetyl-β-d-glucosaminidase (NAG)) are positively associated with six metabolites, including mono-benzylphthalate (MBzP), mono-2-ethylhexylphthalate (MEHP), mono-2-ethyl-5-oxohexyphthalate (MEOHP), mono-2-ethyl-5-hydroxyhexylphthalate (MEHHP), mono-2-ethyl-5-carboxypentylphthalate (MECPP), and mono-2-carboxymethyl-hexyl phthalate (MCMHP) (P < 0.05). Logistic analysis showed that the prevalence of hyperALBuria, hyperB2Muria, hyperNAGuria, or potentially impaired renal function (PIRF) were positively associated with urinary levels of MBzP, MEOHP, and MECPP, respectively (P < 0.05). Co-exposure to identified risk metabolites monoethylphthalate (MEP), MBzP, MEHP, MEOHP, MECPP, MEHHP, and MCMHP increased the risk of having impaired renal function.

CONCLUSION

Certain metabolites of phthalates, including bis (2-ethylhexyl) phthalate (DEHP) and benzyle butyl phthalate (BBzP), were associated with impaired renal function in Shanghai adults.

Developmental toxicity of dibutyl phthalate and citrate ester plasticizers in Xenopus laevis embryos

Citrate esters have been considered as alternatives to phthalate plasticizers. Being considered to have low toxicity in mammals, their toxicological information for aquatic animals remains poorly understood. We examined the developmental toxicity of citrate esters including tributyl O-acetylcitrate (ATBC), triethyl 2-acetylcitrate (ATEC), and trihexyl O-acetylcitrate (ATHC) together with dibutyl phthalate (DBP) based on the frog embryo teratogenesis assay-Xenopus (FETAX). ATBC has the lowest 96 h LC₅₀ and 96 h EC₅₀ values. In RT-qPCR, the ratio of bax and bcl-2 mRNA was significantly increased by DBP, but not by ATBC, ATEC and ATHC. DNA fragmentation was obvious in DBP-treated tadpoles, but not in those treated with ATBC and ATEC, whereas ATHC caused necrotic DNA degradation. Lipid hydroperoxide levels in tadpoles were significantly increased by DBP and ATHC, but not by ATBC and ATEC, suggesting that induction of oxidative stress by DBP and ATHC in embryos. In tadpoles with head abnormalities, basihyal bone, ceratohyal bone and Meckel's cartilage were frequently missed together with reduction in branchial gill bones. Col2a1 mRNA in the head of tadpoles was significantly decreased by low concentration of DBP, ATHC, and high concentration of ATEC. In stage 25 embryos FoxN3 mRNA, a master regulator for differentiation of neural crest cells to chondrocytes in head, was significantly decreased by DBP and ATHC, but not by ATBC and ATEC. In conclusion, ATEC was recommended as the alternative to phthalate plasticizer having the lowest developmental toxicity in amphibian embryos.

Maternal exposure to di-n-butyl phthalate (DBP) promotes epithelial-mesenchymal transition via regulation of autophagy in uroepithelial cell

Maternal exposure to di-n-butyl phthalate (DBP) induces hypospadias, but the underlying mechanisms remain elusive. Here we hypothesize that aberrant activation of autophagy and epithelial-mesenchymal transition (EMT) are the leading cause of DBP-related hypospadias. Pregnant rats received DBP orally at a dose of 750 mg/kg/day during gestational days 14-18. In DBP-induced hypospadiac male offspring, immunohistochemistry (IHC) staining and Western blot showed increased expression of autophagy and EMT markers in genital tubercle (GT) tissue compared to the control. In addition, lower testosterone levels and androgen receptor (AR) expression in GT tissue were detected. In vitro studies revealed that impaired AR signaling was involved in DBP-induced autophagy and autophagy activation furthermore promoted EMT in urethral epithelial cells. DBP combined with chloroquine, an autophagy inhibitor, reduced the expression of EMT markers compared with DBP treatment alone, while DBP combined with the autophagy inducer rapamycin elevated the expression of EMT markers. The autophagy-lysosomal pathway inhibitor CQ but not proteasome inhibitor MG-132 rescued the decrease of E-cadherin after DBP treatment, which indicated autophagy-induced E-cadherin degradation contributes to DBP-related EMT. Taken together, our findings show that prenatal exposure to DBP induces abnormal autophagy and EMT that may play important roles in hypospadias development.