Conceptualizing the Role of the Microbiome as a Mediator and Modifier in Environmental Health Studies: A Scoping Review of Studies of Triclosan and the Microbiome

PURPOSE OF REVIEW

Triclosan is an endocrine-disrupting antimicrobial additive that is suspected of contributing to antibiotic resistance and altering the microbiome. In this scoping review, we summarize what is known about the association between triclosan exposure and the microbiome using evidence from in vivo and epidemiologic studies.

RECENT FINDINGS

Our review includes 11 rodent studies, seven fish studies, and five human studies. Evidence from animal studies suggests that triclosan decreases the diversity of the microbiome, although only one epidemiologic study agreed. Most studies suggest that triclosan alters the microbial community beta diversity, but disagree on which taxa contributed to compositional differences. Taxa in the Bacteroidetes, Firmicutes, and Proteobacteria may be more influenced by triclosan than those in other phyla. Studies on triclosan and the microbiome were scarce and were inconclusive as to the effects of triclosan on the microbiome. Additional research is needed to clarify windows of heightened susceptibility of the microbiome to triclosan. We recommend guidelines for future microbiome research in environmental health to increase comparability across studies.

Triclosan induces earlier puberty onset in female mice via interfering with L-type calcium channels and activating Pik3cd

Triclosan (TCS) is a broad-spectrum antibacterial chemical widely presents in people's daily lives. Epidemiological studies have revealed that TCS exposure may affect female puberty development. However, the developmental toxicity after low-dose TCS continuous exposure remains to be confirmed. In our study, 8-week-old ICR female mice were continuously exposed to TCS (30, 300, 3000 μg/kg/day) or vehicle (corn oil) from 2 weeks before mating to postnatal day 21 (PND 21) of F1 female mice, while F1 female mice were treated with TCS intragastric administration from PND 22 until PND 56. Vaginal opening (VO) observation, hypothalamic-pituitary-ovarian (HPO) axis related hormones and genes detection, and ovarian transcriptome analysis were carried out to investigate the effects of TCS exposure on puberty onset. Meanwhile, human granulosa-like tumor cell lines (KGN cells) were exposed to TCS to further explore the biological mechanism of the ovary in vitro. The results showed that long-term exposure to low-dose TCS led to approximately a 3-day earlier puberty onset in F1 female mice. Moreover, TCS up-regulated the secretion of estradiol (E2) and the expression of ovarian steroidogenesis genes. Notably, ovarian transcriptomes analysis as well as bidirectional validation in KGN cells suggested that L-type calcium channels and Pik3cd were involved in TCS-induced up-regulation of ovarian-related hormones and genes. In conclusion, our study demonstrated that TCS interfered with L-type calcium channels and activated Pik3cd to up-regulate the expression of ovarian steroidogenesis and related genes, thereby inducing the earlier puberty onset in F1 female mice.

Silver acetate and Triclosan Antimicrobial Graft Evaluation for surgical Repair of aortic disease (STAGER Study)

BACKGROUND

The aim of this study was to assess perioperative and late performance of a silver acetate and triclosan impregnated antimicrobial vascular graft (Intergard Synergy, Intervascular SAS, La Ciotat, France) during open surgical repair of abdominal aortic aneurysms (AAA), and to compare it with standard polyester grafts ones.

METHODS

This retrospective single-centre study (STAGER Study, clinicaltrials.gov: NCT04557254) included patients undergone non-infectious AAA surgical repair between 2012 and 2019, divided into two groups according to the implanted aortic prosthesis: standard polyester graft (PolyG) and silver-triclosan graft (SynG). Early primary endpoints were 30-day mortality, major adverse events (MAEs), and reintervention rates; late primary endpoints were overall and aortic-related survival, reintervention-free survival, and graft infection rate at a mean follow-up (FU) of 49.4±26.8 months.

RESULTS

Five hundred forty-seven patients were included [PolyG 49%, and SynG 51%]. Both groups were substantially homogeneous in risk factors and demographics. Two patients died within 30 days. In-hospital MAE rate [PolyG 14.2% vs. SynG 10.7%; P=.248] and 30-day reintervention rate were not significantly different [PolyG 2.6% vs. SynG 1.4%; P=.374]. At 5 years, overall survival in the PolyG and SynG groups were 85% and 84%, respectively. Reintervention-free survival was 82% for both groups. Aortic-related survival was 95% and 96%, respectively. Graft infection was observed in 8 (3.3%) PolyG patients and 5 (1.8%) SynG patients.

CONCLUSIONS

Silver acetate and triclosan impregnated grafts demonstrated good early and mid-term results, being considered safe and durable for AAA open repair. Similar graft infection and related death rates were observed compared to polyester standard grafts, supporting non-superiority of one graft over the other.

Associations between seminal plasma triclosan and low sperm quality: A case-control study

OBJECTIVE

Triclosan (TCS), a novel endocrine disrupter, has induced widespread human exposure due to its widespread use in personal care products. Environmental TCS exposure was suggested to be associated with human semen quality. However, little is known about seminal plasma TCS concentration and the risk of low sperm quality. This case-control study is established to examine the relationship between seminal plasma TCS and the risk of low sperm quality.

STUDY DESIGN

One hundred men with low sperm quality as cases and one hundred normal men as controls were recruited a fertility clinic in Shijiazhuang, China, during 2018-2019. Seminal plasma TCS concentration was determined using an ultrahigh-performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS). Sperm concentration, sperm count, sperm motility and sperm progressive motility were evaluated according to World Health Organization (WHO) guidelines to assess the sperm quality. We used the Mann-Whitney rank-sum test and Kruskal-Wallis test to assess the differences of seminal plasma TCS concentration between the cases and the controls. In addition, logistic regression analysis was used to estimate the associations between seminal plasma TCS concentrations and low sperm quality risk adjusting for age, body mass index (BMI), abstinence time, smoking, and drinking RESULTS AND CONCLUSIONS: The level of seminal plasma TCS was observed slightly but not significantly higher in the case group than the control group. We also observed significant association between seminal plasma TCS concentrations and semen parameters in both control and case groups. Moreover, the seminal plasma TCS levels at the fourth quartile were found to be more likely to exhibit low sperm quality risk with increased adjusted odds ratios of 2.36 (95% confidence interval 1.03-5.39) compared to the first quartile. Our results reveal that seminal plasma TCS concentration was positively associated with low sperm quality risk.

Urinary Phenols in Early to Midpregnancy and Risk of Gestational Diabetes Mellitus: A Longitudinal Study in a Multiracial Cohort

Environmental phenols are ubiquitous endocrine disruptors and putatively diabetogenic. However, data during pregnancy are scant. We investigated the prospective associations between pregnancy phenol concentrations and gestational diabetes mellitus (GDM) risk. In a nested matched case-control study of 111 individuals with GDM and 222 individuals without GDM within the prospective PETALS cohort, urinary bisphenol A (BPA), BPA substitutes (bisphenol F and bisphenol S [BPS]), benzophenone-3, and triclosan were quantified during the first and second trimesters. Cumulative concentrations across the two times were calculated using the area under the curve (AUC). Multivariable conditional logistic regression examined the association of individual phenols with GDM risk. We conducted mixture analysis using Bayesian kernel machine regression. We a priori examined effect modification by Asian/Pacific Islander (A/PI) race/ethnicity resulting from the case-control matching and highest GDM prevalence among A/PIs. Overall, first-trimester urinary BPS was positively associated with increased risk of GDM (adjusted odds ratio comparing highest vs. lowest tertile [aORT3 vs. T1] 2.12 [95% CI 1.00-4.50]). We identified associations among non-A/Ps, who had higher phenol concentrations than A/PIs. Among non-A/PIs, first-trimester BPA, BPS, and triclosan were positively associated with GDM risk (aORT3 vs. T1 2.91 [95% CI 1.05-8.02], 4.60 [1.55-13.70], and 2.88 [1.11-7.45], respectively). Triclosan in the second trimester and AUC were positively associated with GDM risk among non-A/PIs (P < 0.05). In mixture analysis, triclosan was significantly associated with GDM risk. Urinary BPS among all and BPA, BPS, and triclosan among non-A/PIs were associated with GDM risk. Pregnant individuals should be aware of these phenols' potential adverse health effects.

Triclosan and Its Consequences on the Reproductive, Cardiovascular and Thyroid Levels

Hygiene is essential to avoid diseases, and this is thanks to daily cleaning and disinfection habits. Currently, there are numerous commercial products containing antimicrobial agents, and although they are efficient in disinfecting, it is still not known the effect of the constant use of these products on human health. In fact, a massive use of disinfectants has been observed due to COVID-19, but the possible adverse effects are not yet known. Triclosan is one of the antimicrobial agents used in cosmetic products, toothpaste, and disinfectants. This compound is an endocrine disruptor, which means it can interfere with hormonal function, with its estrogenic and androgenic activity having already been stated. Even if the use of triclosan is well-regulated, with the maximum allowed concentration in the European Union of 0.3% (m/m), its effects on human health are still uncertain. Studies in animals and humans suggest the possibility of harmful health outcomes, particularly for the reproductive system, and in a less extent for the cardiovascular and thyroid functions. Thus, the purpose of this review was to analyse the possible implications of the massive use of triclosan, mainly on the reproductive and cardiovascular systems and on the thyroid function, both in animals and humans.

Pregnancy Exposure to Phenols and Anthropometric Measures in Gestation and at Birth

BACKGROUND

Some synthetic phenols alter pathways involved in fetal development. Despite their high within-subject temporal variability, earlier studies relied on spot urine samples to assess pregnancy exposure. In this study, we examined associations between prenatal phenol exposure and fetal growth.

METHODS

We measured concentrations of two bisphenols, four parabens, benzophenone-3, and triclosan in 478 pregnant women in two weekly pools of 21 samples each, collected at 18 and 34 gestational weeks. We used adjusted linear regressions to study associations between phenol concentrations and growth outcomes assessed twice during pregnancy and at birth.

RESULTS

Benzophenone-3 was positively associated with all ultrasound growth parameters in at least one time point, in males but not females. In females, butylparaben was negatively associated with third-trimester abdominal circumference and weight at birth. We observed isolated associations for triclosan (negative) and for methylparaben and bisphenol S (positive) and late pregnancy fetal growth.

CONCLUSIONS

Our results suggest associations between prenatal exposure to phenols and fetal growth. Benzophenone-3 was the exposure most consistently (positively) associated across all growth parameters.

Effect of triclosan on the pathogenesis of allergic diseases among children

BACKGROUND

Few studies have assessed associations between allergic diseases and antibacterial agents in Taiwanese children.

OBJECTIVE

This study aimed to investigate the association of triclosan (TCS) exposure with allergic diseases among preschoolers, disease-specific IgE titers, and a child's sex.

METHODS

Pediatric data were obtained from the Childhood Environment and Allergic Diseases Study (CEAS; 2010) cohort, and their urine and blood samples were used to analyze TCS and IgE concentrations (age 3 group). Three years later, clinical data were obtained again from the age 3 group (age 6 group). Correlations of TCS levels at ages 3 and 6 years with IgE levels and allergic diseases were evaluated.

RESULTS

The TCS levels were higher at age 3 than at age 6 (geometric mean, 1.05 ng/ml vs 0.37 ng/ml). TCS levels were positively correlated with serum IgE levels at ages 3 and 6 years. Asthma and atopic dermatitis were significantly associated with TCS (adjusted OR 1.14, 95% confidence interval [CI] 1.01-1.29; OR 1.22, 95% CI 1.05-1.41). Sex-stratified analysis revealed that TCS levels were positively correlated with IgE levels among boys in the age 6 group and significantly associated with asthma, allergic rhinitis, and atopic dermatitis among boys.

SIGNIFICANCE

TCS exposure is associated with IgE levels and a potentially high risk of pediatric atopic disorders.

The Influence of Triclosan on the Thyroid Hormone System in Humans - A Systematic Review

OBJECTIVES

Triclosan is an antibacterial agent suspected to disrupt the endocrine system. The aim of this study was to investigate the influence of triclosan on the human thyroid system through a systematic literature review of human studies.

METHODS

Eligibility criteria and method of analysis were registered at Prospero (registration number: CRD42019120984) before a systematic search was conducted in Pubmed and Embase in October 2020. Seventeen articles were found eligible for inclusion. Thirteen studies were observational, while four had a triclosan intervention. Participants consisted of pregnant women in eight studies, of men and non-pregnant women in seven studies and of chord samples/newborns/children/adolescents in six studies. The outcomes were peripheral thyroid hormones and thyroid-stimulating hormone (TSH) in blood samples.

RESULTS

Several studies found a negative association between triclosan and triiodothyronine and thyroxine, and a positive association with TSH; however, the opposite associations or no associations were also found. In general, the studies had limited measurement timepoints of thyroid outcomes, and the interventional studies used low concentrations of triclosan. Thus, study design limitations influence the quality of the dataset and it is not yet possible to conclude whether triclosan at current human exposure levels adversely affects the thyroid hormone system.

CONCLUSIONS

Further larger studies with more continuity and more elaborate outcome measurements of thyroid function are needed to clarify whether triclosan, at current exposure levels, affects the human thyroid hormone system.

SYSTEMATIC REVIEW REGISTRATION

http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42019120984, identifier PROSPERO (CRD42019120984).

In vitro and in vivo estrogenic activity of triclosan

Triclosan (TCS) is an antibacterial and antifungal agent used in many consumer products and exhibits a chemical structure similar to non-steroidal estrogen, which is known to induce endocrine disruption. Triclosan has been found in human plasma, urine, and breast milk, and the safety of TCS-containing products has been disputed. Although studies attempted to determine the estrogenic activity of TCS, no clear results have emerged. The aim of the present study was to examine estrogenic activity of TCS using an in vitro E-screen assay and an in vivo uterotrophic assay. The in vitro E-screen assay demonstrated that TCS significantly enhanced proliferation of MCF-7 breast cancer cells, although not in a concentration-dependent manner. The in vivo uterotrophic results showed no significant change in the weight of uteri obtained from TCS-administered Sprague-Dawley rats. Further, to understand the estrogenic activity attributed to TCS at the molecular level, gene-expression profiling of uterus samples was performed from both TCS- or estrogen-treated rats and the genes and cellular processes affected by TCS or estrogen were compared. Data demonstrated that both the genes and cellular processes affected by TCS or estrogen were significantly similar, indicating the possibility that TCS-mediated estrogenic activity occurred at the global transcriptome level. In conclusion, in vitro and gene-profiling results suggested that TCS exhibited estrogenic activity.

Association Between Gestational Exposure to Toxicants and Autistic Behaviors Using Bayesian Quantile Regression

Autism spectrum disorder, which is characterized by impaired social communication and stereotypic behaviors, affects 1%-2% of children. Although prenatal exposure to toxicants has been associated with autistic behaviors, most studies have been focused on shifts in mean behavior scores. We used Bayesian quantile regression to assess the associations between log2-transformed toxicant concentrations and autistic behaviors across the distribution of behaviors. We used data from the Maternal-Infant Research on Environmental Chemicals study, a pan-Canadian cohort (2008-2011). We measured metal, pesticide, polychlorinated biphenyl, phthalate, bisphenol-A, and triclosan concentrations in blood or urine samples collected during the first trimester of pregnancy. Using the Social Responsiveness Scale (SRS), in which higher scores denote more autistic-like behaviors, autistic behaviors were assessed in 478 children aged 3-4 years old. Lead, cadmium, and most phthalate metabolites were associated with mild increases in SRS scores at the 90th percentile of the SRS distribution. Manganese and some pesticides were associated with mild decreases in SRS scores at the 90th percentile of the SRS distribution. We identified several monotonic trends in which associations increased in magnitude from the bottom to the top of the SRS distribution. These results suggest that quantile regression can reveal nuanced relationships and, thus, should be more widely used by epidemiologists.

Topical exposure to triclosan inhibits Th1 immune responses and reduces T cells responding to influenza infection in mice

Healthcare workers concurrently may be at a higher risk of developing respiratory infections and allergic disease, such as asthma, than the general public. Increased incidence of allergic diseases is thought to be caused, in part, due to occupational exposure to chemicals that induce or augment Th2 immune responses. However, whether exposure to these chemical antimicrobials can influence immune responses to respiratory pathogens is unknown. Here, we use a BALB/c murine model to test if the Th2-promoting antimicrobial chemical triclosan influences immune responses to influenza A virus. Mice were dermally exposed to 2% triclosan for 7 days prior to infection with a sub-lethal dose of mouse adapted PR8 A(H1N1) virus (50 pfu); triclosan exposure continued until 10 days post infection (dpi). Infected mice exposed to triclosan did not show an increase in morbidity or mortality, and viral titers were unchanged. Assessment of T cell responses at 10 dpi showed a decrease in the number of total and activated (CD44hi) CD4+ and CD8+ T cells at the site of infection (BAL and lung) in triclosan exposed mice compared to controls. Influenza-specific CD4+ and CD8+ T cells were assessed using MHCI and MHCII tetramers, with reduced populations, although not reaching statistical significance at these sites following triclosan exposure. Reductions in the Th1 transcription factor T-bet were seen in both activated and tetramer+ CD4+ and CD8+ T cells in the lungs of triclosan exposed infected mice, indicating reduced Th1 polarization and providing a potential mechanism for numerical reduction in T cells. Overall, these results indicate that the immune environment induced by triclosan exposure has the potential to influence the developing immune response to a respiratory viral infection and may have implications for healthcare workers who may be at an increased risk for developing infectious diseases.

Triclosan changes community composition and selects for specific bacterial taxa in marine periphyton biofilms in low nanomolar concentrations

The antibacterial agent Triclosan (TCS) is a ubiquitous environmental contaminant due to its widespread use. Sensitivity to TCS varies substantially among eu- and pro-karyotic species and its risk for the marine environment remains to be better elucidated. In particular, the effects that TCS causes on marine microbial communities are largely unknown. In this study we therefore used 16S amplicon rDNA sequencing to investigate TCS effects on the bacterial composition in marine periphyton communities that developed under long-term exposure to different TCS concentrations. Exposure to TCS resulted in clear changes in bacterial composition already at concentrations of 1 to 3.16 nM. We conclude that TCS affects the structure of the bacterial part of periphyton communities at concentrations that actually occur in the marine environment. Sensitive taxa, whose abundance decreased significantly with increasing TCS concentrations, include the Rhodobiaceae and Rhodobacteraceae families of Alphaproteobacteria, and unidentified members of the Candidate division Parcubacteria. Tolerant taxa, whose abundance increased significantly with higher TCS concentrations, include the families Erythrobacteraceae (Alphaproteobacteria), Flavobacteriaceae (Bacteroidetes), Bdellovibrionaceae (Deltaproteobacteria), several families of Gammaproteobacteria, and members of the Candidate phylum Gracilibacteria. Our results demonstrate the variability of TCS sensitivity among bacteria, and that TCS can change marine bacterial composition at concentrations that have been detected in the marine environment.

Salicylic acid application alleviates the adverse effects of triclosan stress in tobacco plants through the improvement of plant photosynthesis and enhancing antioxidant system

Triclosan (TCS) is a chlorophenol which is highly bacteriostatic and used in a wide array of consumer products. TCS is now one of the most commonly detected organic pollutants in the sewage sludges. The sludge utilization for fertilizers on agricultural land would pose the risk of causing adverse effects on plant growth and yield by TCS. However, the toxicity of TCS toward plants is comparatively less understood. In this study, we assessed the effects of TCS on tobacco plants which were grown in MS medium or soils containing various concentrations of TCS. Our results indicated that TCS at the concentration of 2 mg/L could strongly inhibit the tobacco seed germination. TCS could suppress tobacco plant growth in soil with different concentrations (10, 20, and 50 mg/kg) of TCS through the downregulation of chlorophyll contents, restricting photosynthesis and increasing generation of reactive oxygen species (ROS). Salicylic acid (SA) plays important roles in the stress response of plants. The role of exogenous SA application in protecting tobacco plants from TCS stress was also investigated in this study. SA application could significantly increase net photosynthesis, enhance antioxidant enzyme activity, and thereby enhancing tobacco plant tolerance to TCS. Moreover, the activation of MPK3 and MPK6 induced by TCS was downregulated in plants with the treatment of SA. It was thus referred that mitogen-activated protein kinases (MAPKs) might play a key role in the signal transduction of TCS stress, and this process might be regulated by SA signaling. Overall, our results demonstrated that TCS had negative impacts on tobacco plants and SA played a protective role on tobacco plants against TCS stress.

Associations of Prenatal Exposure to Triclosan and Maternal Thyroid Hormone Levels: A Systematic Review and Meta-Analysis

OBJECTIVE

To quantitatively evaluate associations between exposure to triclosan during pregnancy and maternal thyroid hormone levels.

METHOD

The databases of PubMed, Embase, Web of Science and Cochrane Library were systematically searched to identify relevant studies on the relationship between prenatal exposure to triclosan and maternal levels of serum thyroid hormone published before October 22, 2019. Stata 12.0 was used to examine the heterogeneity among the eligible studies.

RESULTS

Seven studies involving a total of 4,136 participants were included. Overall, descriptive analysis provided no indication that exposure to TCS during pregnancy was related to either maternal FT4 levels (ES = 0.01, 95% CI: -0.03 to 0.05, P = 0.00) or TSH levels (ES = -0.03, 95% CI: -0.13 to 0.07, P = 0.412). Although the results were statistically insignificant, with the increase of urine TCS concentration, maternal FT4 levels exhibited a tendency to increase while TSH levels had a tendency to decrease during pregnancy.

CONCLUSION

The results indicated that exposure to triclosan during pregnancy has no significant influence on maternal levels of thyroid hormone. On account of the inconsistency of existing research designs and study locations, further studies and replication are necessary to confirm these findings.

[Risk of pathoosophermia in men with joint exposure to endocrine disruptors]

The purpose of the study is to assess the risk of pathozoospermia with the combined effect of bisphenol A, triclosan and 4-nonylphenol.

MATERIALS AND METHODS

84 samples of sperm were studied in men with normo-and patozoospermia. In seminal fluid, the concentrations of bisphenol A, triclosan and 4-nonylphenol were simultaneously determined by gas chromatography with mass spectrometry (GC-MS). The spermiological study was carried out according to the WHO recommendations (2010) taking into account the assessment of the number of spermatozoa, their motility and morphology, as well as sperm damage. The results were subjected to statistical processing using the Mann-Whitney U-test and the multiple logistic regression method. Results were considered statistically significant at p<0.05.

RESULTS

Bisphenol A was found in 100% of the ejaculate samples with a median concentration of 0.150 ng/ml. Triclosan and 4-nonylphenol were detected in 84.3% and 98.1% of ejaculate samples with a median concentration of 0.11 ng/ml. and 0.16 ng/ml, respectively. The comparison groups were statistically significantly distinguished by the concentrations of bisphenol A and triclosan (p<0.001; p=0.018), respectively, as well as the DNA index of spermatozoa fragmentation (p=0.002). Bisphenol A, by increasing the concentration in seminal fluid by 0,1 ng/ml, increased the chance of developing pathosospermia by 24.9 times. The effect of triclosan and 4-nonylphenol on pathosospermia was not statistically significant. In a multiple logistic regression equation describing the joint effect of EDs on patozoospermia, as well as the ratio of the chances of its occurrence with a change in the concentration of one of the endocrine disruptors per unit while fixing the other variables, the coefficients of triclosan and 4-nonylphenol on the patozoospermia were also not statistically significant. In addition, the confidence interval for the odds ratio included one.

CONCLUSION

The development of pathozoospermia is primarily associated with the effect of bisphenolA in seminal fluid in men. It should be assumed that there is no synergistic effect of endocrine disruptors on patozoospermia.

The Impact of Early-Life Exposure to Antimicrobials on Asthma and Eczema Risk in Children

PURPOSE OF REVIEW

We examined recent research on associations of prenatal and early-childhood exposure to the antimicrobial compounds, triclosan, and parabens, with the risk of asthma and eczema in children. We will discuss potential biological mechanisms of this association and highlight strengths and limitations of the study design and exposure assessment of current findings.

RECENT FINDINGS

Results of available toxicological and epidemiologic studies indicate a potential link of triclosan and paraben exposures with asthma and eczema in children, as well as changes in microbiome diversity and immune dysfunction, which could possibly mediate an association with the health outcomes. A small number of studies suggest that triclosan and paraben exposures could be related to the risk of asthma and eczema in children. Although current findings are far from conclusive, there is emerging evidence that changes in microbiome diversity and immune function from antimicrobial exposure may mediate these relations.

Maternal exposure to triclosan causes fetal development restriction, deregulation of the oestrous cycle, and alters uterine tissue in rat offspring

The aim of the present study was to evaluate the effects of maternal exposure to triclosan (TCS) during pregnancy and lactation on the uterine morphology of rat offspring. For this, 32 Wistar rat dams were distributed into four dose groups (eight mothers per group), and gavage daily, throughout pregnancy and lactation, as follows: Group I-control (GI): corn oil; Group II (GII): TCS diluted in corn oil at a dose of 75 mg/kg/d; Group III (GIII): TCS diluted in corn oil at a dose of 150 mg/kg/d; Group IV (GIV): TCS diluted in corn oil at a dose of 300 mg/kg/d. A female pup of each mother was selected, and at 90 days the pups were euthanized for weighing and collection of the uterus for histomorphometric analysis. The results showed that the mean litter weight was minor in all the groups treated with TCS, when compared with control. The levels thyroid hormones thyroxine (T4) and triiodothyronine (T3) in TCS mother rats were reduced; however the levels of thyroid stimulating hormone (TSH) were increases. The offspring of all groups exposed to TCS presented deregulation of the estrous cycle, compared with control. Analysis of the uterine histological structure demonstrated that all layers of the uterus were affected by the administration of TCS, and the morphometric analysis showed increased uterine layers thickness in the treated groups. We concluded that maternal exposure to TCS during pregnancy and lactation causes intrauterine development restriction, deregulation of the oestrous cycle, and alters uterine tissue in rat offspring.

Early-life triclosan exposure and parent-reported behavior problems in 8-year-old children

BACKGROUND

Triclosan exposure may decrease circulating thyroxine levels or cause neuron apoptosis, which in turn may adversely affect neurodevelopment. However, few studies have examined the association of early life triclosan exposure with child behavior.

OBJECTIVE

To quantify the association between early-life triclosan exposure and child behavior at age 8-years in 202 mother-child pairs from the HOME study (Cincinnati, OH; enrolled: 2003-2006).

METHODS

We quantified urinary triclosan concentrations up to 3 times in mothers (16-weeks, 26-weeks, and delivery) and up to 6 times in children (1, 2, 3, 4, 5, and 8 years). Parents rated children's problem behaviors at age 8-years using the Behavioral Assessment System for Children-2 (BASC-2). Adjusting for covariates and accounting for exposure measurement error, we estimated changes in behavior problem scores per 10-fold increase in mean gestational and childhood triclosan concentrations. In addition, we estimated sex-specific associations.

RESULTS

Child sex modified the association of gestational and childhood triclosan with several BASC-2 scales (sex × triclosan p-values < 0.2). In boys, increasing gestational triclosan was associated with higher behavioral symptom index (β: 4.5; 95% CI: 1.0, 8.1), externalizing problems (β: 5.0; 95% CI: 1.2, 9.0), attention problem (β: 6.6; 95% CI: 2.4, 11), hyperactivity (β: 6.4; 95% CI: 2.1, 11), and somatization (β: 3.8; 95% CI: 0.3, 7.3) scores. In contrast, triclosan-BASC-2 associations in girls were generally null and not statistically significant. We observed similar patterns of associations between childhood triclosan and these same behavioral scores; however, their magnitude decreased substantially after adjusting for gestational triclosan and associations were not statistically significant.

CONCLUSION

In this cohort, increasing gestational and childhood urinary triclosan concentrations were associated with higher behavior problem scores in 8-year old boys, but not girls.

The influence of temperature on the effects induced by Triclosan and Diclofenac in mussels

Little is known about the consequences of exposure to pharmaceuticals and personal care products (PPCPs) in elevated temperatures associated with climate change. To increase the knowledge on this topic, Mytilus galloprovincialis mussels were exposed to 1.0 μg/L of either the antimicrobial Triclosan (TCS) or the anti-inflammatory drug Diclofenac (DIC), at control (17 °C) and 4 °C raised (21 °C) temperatures for 28 days. Triclosan and DIC concentrations in the water and tissues were subsequently measured and related to biomarker responses including: energy metabolism (electron transport system (ETS) activity, glycogen and protein reserves), oxidative stress markers, glutathione balance between the reduced and the oxidised form (GSH/GSSG), and damage to proteins and lipids. Mussels responded to the increase in temperature and drug exposure by lowering their metabolic rate (decreased ETS), increasing their endogenous reserves and antioxidant defences, thus preventing oxidative stress damage, with the exception of DIC exposure at the higher temperature. In all cases, GSH/GSSG ratio was reduced in detriment of the antioxidant form at both PPCPs exposures and elevated temperature with no additive effect due to combined stressors. Overall, either drug exposure or increased temperature could compromise the ability of mussels to withstand further insults.

Effects of miR-181a-5p abnormal expression on zebrafish (Danio rerio) vascular development following triclosan exposure

Triclosan (TCS), one of the important bactericides, is widely used in personal care products, and its chronic exposure leads to severe toxic effects on the growth and development of blood vessels in zebrafish (Danio rerio). Herein, we screened out three differentially expressed miRNAs (miR-181a-5p, miR-132-3p and miR-128-3p) by sequencing and qRT-PCR analyses of 4-96-hpf TCS-exposed zebrafish, among which miR-181a-5p was found to regulate many signaling pathways involved in fatty acid biosynthesis and phosphatidylimositol signaling systems. By O-dianisidine staining, TCS-exposure resulted in decreased distribution of red blood cells and induced blood hypercoagulable state and thrombotic effects. Defective subintestinal veins (SIVs), and decreased branching and curvature of blood vessels were observed with increasing TCS-exposure concentrations. After microinjection of miR-181a-5p mimic and inhibitor, zebrafish malformation type and percentage were prominently increased such as distorted SIV vessels along with reduced venation and abnormal branches by ALP staining. Overexpressed miR-181a-5p had a greater effect on development and branching patterns of arteries and veins than its knockdown. By laser confocal microscopy observation, the 72-hpf Tg (flk1: mCherry) zebrafish obviously displayed vascular proliferation and ablation in the miR-181a-5p mimic group. Microinjection of miR-181a-5p mimics and inhibitors led to abnormal expressions (20-50%) of two key target genes (pax2a and vash2) by WISH, and increased malformation percentages (18-45%) by IOD analysis. Overexpression of vash2 led to the inhibitory or promoting effects on the expression of PI3K signaling pathway-related genes, proving that the effect of vash2 on development of blood vessels could be realized by inhibiting PI3K signaling pathway. These observations lay theoretical foundation for deep insight into the molecular mechanisms on TCS-induced cardiovascular diseases.

Dietary Lactobacillus plantarum ST-III alleviates the toxic effects of triclosan on zebrafish (Danio rerio) via gut microbiota modulation

The probiotics, Lactobacillus plantarum ST-III, plays an important role in modulating microbiota and alleviating intestinal metabolic disorders. Herein, we reported that Lactobacillus increases biodiversity of zebrafish gut flora, and attenuates toxic effects from chronic triclosan (TCS) exposure. Lactobacillus-feeding recovered the species and amount of microorganisms in the intestines of zebrafish, and inhibited toxin production by saprophytic bacterial growth. Abnormal physiological indexes and malonaldeyhde content resulting from TCS exposure were effectively alleviated. Additionally, lipid-metabolism disorders, such as increased triglyceride and total cholesterol levels, were attenuated by a probiotics diet. The number of CD4⁺ T cell lymphocytes in the lamina propria of the duodenal mucosa was decreased in zebrafish receiving a Lactobacillus diet compared to the TCS-exposed group, showing a consistent expression trend for six immune genes (NF-κB, IL-1β, TNF-α, lysozyme, TLR4α, IL-10) in the intestinal mucosa. Histopathological observations of intestines, spleen and kidney showed that TCS exposure produced severe damage to the morphology and structure of immune and metabolism-related organs. Lactobacillus was capable of mitigating this damage, but bile salt hydrolase, an active extract of Lactobacillus, was not an effective mitigation strategy. The Lactobacillus-induced decrease in the number of inflammatory cells confirmed its role in preventing inflammatory injury. Three behavioral tests (T-maze, bottom dwelling and social interaction) indicated that a probiotics diet improved zebrafish movement and learning/memory capacity, effectively alleviating anxiety behavior due to TCS exposure. These findings inform development of beneficial strategies to alleviate intestinal metabolic syndromes and neurodegenerative diseases resulting from exposure to environmental contaminants through modifying gut flora with a probiotics diet.

Types of antiseptics, presentations and rules of use

Antiseptics are chemical substances that when applied topically onto intact skin, mucous membranes or wounds partially or completely reduces the population of living microorganisms in those tissues. Different types of antiseptics are available - those most commonly used in clinical practice being alcohols, iodinated compounds and chlorhexidine. When using an antiseptic, consideration is required of its spectrum of antimicrobial activity, latency, residual effects, possible interferences of the presence of organic material with the activity of the antiseptic, its side effects, compatibility with other antiseptics, and cost. This article is part of a supplement entitled "Antisepsis in the critical patient", which is sponsored by Becton Dickinson.

The association of repeated measurements of prenatal exposure to triclosan with fetal and early-childhood growth

BACKGROUND

Triclosan (TCS) is known to possess endocrine disrupting properties and metabolize rapidly in the human body. Human data concerning repeated measurements of TCS throughout pregnancy in relation to fetal and childhood growth are sparse.

OBJECTIVES

We investigated the associations between multiple measurements of maternal urinary concentrations of TCS during pregnancy and fetal and early-childhood growth.

METHODS

The study population included 850 mother-infant pairs who participated in a prenatal cohort established between 2014 and 2015 in Wuhan. Prenatal TCS exposure was measured in a complete series of urine samples collected at the first, second and third trimesters. General linear models and generalized estimating equation models were applied to evaluate the associations of the averaged maternal urinary concentrations of TCS over trimesters and trimester-specific urinary TCS with the z-scores of estimated fetal weight, head circumference, abdominal circumference, and femur length at 16, 24, and 31 gestational weeks, weight and length at birth, and weight and height at 0.5, 1, and 2 years of age.

RESULTS

In overall infants, we did not observe any significant association of the averaged maternal urinary concentrations of TCS over trimesters with ultrasound parameters and size at birth. However, a positive association of borderline statistical significance was found between averaged prenatal TCS exposure and the third-trimester estimated fetal weight z-score in girls in sex-stratified analyses (β = 0.054, 95% CI: -0.005, 0.113, p = 0.07). Moreover, averaged prenatal TCS exposure was positively associated with 2 year-old weight z-score among total infants (β = 0.046, 95% CI: 0.005, 0.087). After stratifying by sex, the same association was observed in girls with more prominent estimation (β = 0.062, 95% CI: 0.000, 0.124), whereas the association weakened and became not significant in boys (β = 0.033, 95% CI: -0.024, 0.089). TCS exposure at 1st and 2nd-trimester were positively associated with weight z-score at 2 years, in both overall and female infants.

CONCLUSIONS

Prenatal exposure to triclosan was associated with elevated third-trimester estimated fetal weight and 2 year-old weight z-score in girls, and the early and middle stage of pregnancy may be the windows of vulnerability. Apart from these findings, we did not find strong evidence for prenatal triclosan exposure in relation to fetal and early-childhood growth.

Environmental exposure to triclosan and polycystic ovary syndrome: a cross-sectional study in China

OBJECTIVES

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy of women at reproductive age. Although the aetiology of PCOS remains unclear, potential effects of environmental endocrine-disrupting compounds on the development of PCOS have drawn increasing attention. The aim of the current study was to examine the association between triclosan (TCS) and PCOS, and explore possible mechanisms on how TCS may contribute to the development of clinical manifestations of PCOS.

DESIGN

Cross-sectional study.

SETTING

This study was conducted in one tertiary-level hospital located in Zhejiang, China.

PARTICIPANTS

A total of 674 infertile women at 18-45 years of age were recruited in 2014-2015. Participants with (n=84) and without (n=212) PCOS with urinary TCS concentration available were included in the analyses.

METHODS

Urinary TCS concentration was measured using a high-performance liquid chromatography-electrospray ionisation tandem mass spectrometry. Logistic regression model was used to examine the association between TCS and PCOS. Fractional polynomial regression models were built to fit the potential non-linear relationship between TCS concentrations and luteinising hormone (LH) and LH/follicle stimulate hormone (FSH).

RESULTS

The PCOS group had significantly higher level of TCS concentration than the non-PCOS group (the median of TCS (IQR), μg/g creatinine: 1.49 (0.68-3.80) vs 1.06 (0.52-3.02), p=0.0407). Compared with the lowest tertile, the highest tertile of TCS concentration was associated with an increased odd of PCOS (OR 2.12, 95% CI 1.12 to 3.99). After adjusting for potential confounders, the significant association remained (OR 1.99, 95% CI 1.05 to 3.79). Positive relationships were found between TCS levels and LH and LH/FSH ratio in non-PCOS participants.

CONCLUSIONS

TCS exposure at a relatively low level is associated with PCOS in Chinese women. Further epidemiological studies are needed to confirm our finding, which may have important public health implications.

Associations of maternal exposure to triclosan, parabens, and other phenols with prenatal maternal and neonatal thyroid hormone levels

Environmental phenols and parabens are commonly used in personal care products and other consumer products and human exposure to these chemicals is widespread. Although human and animal studies suggest an association between exposure to phenols and parabens and thyroid hormone levels, few studies have investigated the association of in utero exposure to these chemicals and thyroid hormones in pregnant women and their neonates. We measured four environmental phenols (triclosan, benzophenone-3, and 2,4- and 2,5-dichlorophenol), and three parabens (methyl-, propyl-, and butyl paraben) in urine collected from mothers at two time points during pregnancy as part of the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study. We measured free thyroxine (T4), total T4, and thyroid-stimulating hormone (TSH) in serum of the pregnant women (N = 454) and TSH in their neonates (N = 365). We examined potential confounding by a large number of additional chemical exposures and used Bayesian Model Averaging (BMA) to select the most influential chemicals to include in regression models. We observed negative associations of prenatal urinary concentrations of propyl paraben and maternal TSH (β for two-fold increase = -3.26%, 95% CI: -5.55, -0.90) and negative associations of 2,4-dichlorophenol and maternal free T4 (β for two-fold increase = -0.05, 95% CI: -0.08, -0.02), after controlling for other chemical exposures. We observed negative associations of triclosan with maternal total T4 after controlling for demographic variables, but this association became non-significant after controlling for other chemicals (β for two-fold increase = -0.05, 95% CI: -0.11, 0.00). We found evidence that environmental phenols and parabens are associated with lower TSH and free T4 in pregnant women after controlling for related chemical exposures.

Triclosan and triclocarban exposure, infectious disease symptoms and antibiotic prescription in infants-A community-based randomized intervention

Background

Triclosan and triclocarban (TCs) are broad-spectrum antimicrobials that, until recently, were found in a wide variety of household and personal wash products. Popular with consumers, TCs have not been shown to protect against infectious diseases.

Objectives

To determine whether use of TC-containing wash products reduces incidence of infection in children less than one year of age.

Methods

Starting in 2011, we nested a randomized intervention of wash products with and without TCs within a multiethnic birth cohort. Maternal reports of infectious disease symptoms and antibiotic use were collected weekly by automated survey; household visits occurred every four months. Antibiotic prescriptions were identified by medical chart review. Urinary triclosan levels were measured in a participant subset. Differences by intervention group in reported infectious disease (primary outcome) and antibiotic use (secondary outcome) were assessed using mixed effects logistic regression and Fisher’s Exact tests, respectively.

Results

Infectious illness occurred in 6% of weeks, with upper respiratory illness the predominant syndrome. Among 60 (45%) TC-exposed and 73 (55%) non-TC-exposed babies, infectious disease reports did not differ in frequency between groups (likelihood ratio test: p = 0.88). Medical visits with antibiotic prescriptions were less common in the TC group than in the non-TC group (7.8% vs. 16.6%, respectively; p = 0.02).

Conclusions

Although randomization to TC-containing wash products was not associated with decreased infectious disease reports by mothers, TCs were associated with decreased antibiotic prescriptions, suggesting a benefit against bacterial infection. The recent removal of TCs from consumer wash products makes further elucidation of benefits and risks impracticable.

Drivers of contaminant levels in surface water of China during 2000-2030: Relative importance for illustrative home and personal care product chemicals

Water pollution are among the most critical problems in China and emerging contaminants in surface water have attracted rising attentions in recent years. There is great interest in China's future environmental quality as the national government has committed to a major action plan to improve surface water quality. This study presents methodologies to rank the importance of socioeconomic and environmental drivers to the chemical concentration in surface water during 2000-2030. A case study is conducted on triclosan, a home and personal care product (HPCP) ingredient. Different economic and discharge flow scenarios are considered. Urbanization and wastewater treatment connection rates in rural and urban areas are collected or projected for 2000-2030 for counties across China. The estimated usage increases from ca. 86 to 340 t. However, emissions decreases from 76 to 52 t during 2000-2030 under a modelled Organisation for Economic Co-operation (OECD) economic scenario because of the urbanization, migration and development of wastewater treatment plants/facilities (WWTPs). The estimated national median concentration of triclosan ranges 1.5-8.2 ng/L during 2000-2030 for different scenarios. It peaks in 2009 under the OECD and three of the Intergovernmental Panel on Climate Change (IPCC), A2, B1 and B2 economic scenarios, but in 2025 under A1 economic scenario. Population distribution and surface water discharge flow rates are ranked as the top two drivers to triclosan levels in surface water over the 30 years. The development of urban WWTPs was the most important driver during 2000-2010 and the development of rural works is projected to be the most important in 2011-2030. Projections suggest discharges of ingredients in HPCPs - controlled by economic growth - should be balanced by the major expenditure programme on wastewater treatment in China.

Prenatal urinary triclosan concentrations and child neurobehavior

BACKGROUND

Exposure to triclosan, an antimicrobial chemical, is ubiquitous among pregnant women and may reduce thyroid hormone levels that are important for fetal neurodevelopment. Few studies have examined the association between prenatal triclosan exposure and children's neurobehavior.

OBJECTIVE

We investigated the relationship of prenatal urinary triclosan concentrations with children's behavior and cognitive abilities at age three years in a prospective pregnancy and birth cohort in Canada.

METHODS

We measured triclosan in urine samples collected at ~12 weeks of gestation in 794 Canadian women enrolled in a prospective pregnancy and birth cohort study (MIREC) from 2008 to 2011. Around age 3 years, we assessed children's cognitive abilities using the Wechsler Primary and Preschool Scale of Intelligence-III (WPPSI-III), and two scales of the Behavior Rating Inventory of Executive Function-Preschool (BRIEF-P). Parents reported children's problem and reciprocal social behaviors using the Behavior Assessment System for Children-2 (BASC-2) and Social Responsiveness Scale-2 (SRS-2), respectively.

RESULTS

After adjusting for confounders using multivariable linear regression, triclosan was not associated with most of the 30 examined neurobehavioral scales. Each 10-fold increase in triclosan was associated with better WPPSI-III picture completion scores (β: 0.2; 95% CI: 0,0.5) and BASC-2 externalizing (β: -0.5; 95% CI: -1.1, 0) and hyperactivity (β: -0.6; 95% CI: -1.2, -0.1) scores, suggesting less externalizing and hyperactive behaviors. Child sex did not modify these associations.

CONCLUSIONS

In this cohort, urinary triclosan concentrations measured once in early pregnancy were not associated with most assessed aspects of neurobehavior and weakly associated with a few others, but not in the hypothesized direction.

Impacts of prenatal triclosan exposure on fetal reproductive hormones and its potential mechanism

BACKGROUND

Triclosan (TCS) has been widely detected in pregnant women. The reproductive endocrine-disrupting effects of TCS have been observed in humans and animals. Little is known about the potential impact of prenatal TCS exposure on fetal reproductive development as well as its potential mechanism.

OBJECTIVES

We investigated the potential effect of prenatal TCS exposure on fetal reproductive hormones in cord blood and its potential mechanism in relation to placental steroidogenic enzymes.

METHODS

Urinary TCS was detected among 537 healthy pregnant women from a prospective cohort in China. Four reproductive hormones in cord blood, namely E₂ (n=430), T (n=424), LH (n=428) and FSH (n=373), and three steroidogenic enzymes in placenta, namely P450arom (n=233), 3β-HSD (n=227) and 17β-HSD (n=222), were measured.

RESULTS

Prenatal TCS exposure was associated with increased testosterone concentrations in cord blood in a dose-dependent manner. Infants with prenatal TCS levels >0.6μg/L had, on average, a 0.23ng/mL (95% CI: 0.05, 0.45, p=0.02) higher testosterone concentrations in cord blood compared to those with prenatal TCS levels <0.1μg/L. Of note, prenatal TCS exposure was associated with increased testosterone and decreased E₂ concentrations in cord blood among male infants. Adverse associations were found between the prenatal TCS exposure and concentrations of three placental steroidogenic enzymes. 3β-HSD and P450arom demonstrated mediating effects in the association between prenatal TCS exposure and testosterone concentrations in cord blood.

CONCLUSIONS

Our findings suggested potential impacts of prenatal TCS exposure on reproductive hormones in cord blood mediated by steroidogenic enzymes, and male infants were more vulnerable.

Associations between maternal triclosan concentrations in early pregnancy and gestational diabetes mellitus, impaired glucose tolerance, gestational weight gain and fetal markers of metabolic function

BACKGROUND

Triclosan is a phenolic biocide used in a multitude of consumer products and in health care settings. It is widely detected in the American and Canadian populations and has been shown in animal models to act as an endocrine disrupting agent. However, there has been little examination to date of the effects of triclosan exposure in pregnancy on perinatal metabolic outcomes in human populations.

METHODS

Using data from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a Canadian pregnancy cohort, we measured associations of first-trimester urinary triclosan concentrations with total gestational weight gain, gestational diabetes mellitus and impaired glucose tolerance in pregnancy, and fetal markers of metabolic function. Leptin and adiponectin were measured in plasma from umbilical cord blood samples in term neonates and categorized into low (< 10th percentile), intermediate (10th-90th percentile) and high (> 90th percentile) levels. Triclosan concentrations were grouped into quartiles and associations with study outcomes were examined using logistic regression models with adjustment for maternal age, race/ethnicity, pre-pregnancy BMI, education and urinary specific gravity. Restricted cubic spline analysis was performed to help assess linearity and shape of any dose-response relationships. All analyses for leptin and adiponectin levels were performed on the entire cohort as well as stratified by fetal sex.

RESULTS

Triclosan measures were available for 1795 MIREC participants with a live born singleton birth. Regression analyses showed a non-significant inverse association between triclosan concentrations and leptin levels above the 90th percentile that was restricted to female fetuses (OR for highest quartile of triclosan compared to lowest quartile = 0.4 (95% CI 0.2-1.1), p-value for trend across quartiles = 0.02). Triclosan concentrations in the second quartile were associated with elevated odds of adiponectin below the 10th percentile in male fetuses (OR for Q2 compared to Q1 = 2.5, 95% CI 1.1-5.9, p-value for trend across quartiles = 0.93). No significant linear associations between triclosan concentrations and leptin or adiponectin levels in overall or sex-specific analyses were observed from restricted cubic spline analyses. No significant associations were observed in adjusted analyses between triclosan concentrations and gestational diabetes mellitus, impaired glucose tolerance or gestational weight gain.

CONCLUSIONS

This study does not support an association between triclosan concentrations in pregnancy and fetal metabolic markers, glucose disorders of pregnancy, or excessive gestational weight gain.

Histopathological changes and lipid metabolism in the liver of Bufo gargarizans tadpoles exposed to Triclosan

In the current study, the adverse effects of TCS on liver health of B. gargarizans tadpoles were assessed. B. gargarizans larvae were exposed to TCS at 0, 10, 30, 60, and 150 μg L^-1 from Gosner stage 3 until metamorphic climax. The hepatosomatic index (HSI), hepatic histological and ultrastructural features, and transcript levels of genes associated with detoxification and oxidative stress as well as lipid metabolism in the livers were determined. Exposure to 150 μg L^-1 TCS resulted in increased HSI of tadpoles at metamorphic climax. Histological changes characterized by an increase in the number of melanomacrophage, nucleus pyknosis, and deposition of collagen fibers were observed in liver at 60 and 150 μg L^-1 TCS. Moreover, marked ultrastructural alterations including high electron dense in mitochondrial matrix and lipid accumulation were also observed. In addition, abundances of transcripts of Cu/Zn superoxide dismutase (SOD), phospholipid hydroperoxide glutathione peroxidase (PHGPx), and heat shock protein 90 (HSP₉₀) were decreased in larvae exposed to 60 and 150 μg L^-1 TCS, while transcript level of HSP₉₀ was increased at 30 μg L^-1 TCS. Also, abundances of transcripts of acetyl-CoA carboxylase (ACC), carnitine palmitoyltransferase 2 (CPT2), peroxisome proliferator-activated receptor alpha (PPARa), fatty acid elongase 1 (FAE), sterol carrier protein 2 (SCP) were significantly lesser in larvae exposed to 60 and 150 μg L^-1 TCS. Overall, TCS at high levels induced histopathological changes in the liver of B. gargarizans tadpoles. This might have been due to the alteration of oxidative stress-related genes and lipid metabolism-related genes expression levels.

Triclosan: A review on systematic risk assessment and control from the perspective of substance flow analysis

Triclosan (TCS) is a broad spectrum antibacterial agent mainly used in Pharmaceutical and Personal Care Products. Its increasing use over recent decades have raised its concentration in the environment, with commonly detectable levels found along the food web-from aquatic organisms to humans in the ecosystem. To date, there is shortage of information on how to investigate TCS's systematic risk on exposed organisms including humans, due to the paucity of systematic information on TCS flows in the anthroposphere. Therefore, a more holistic approach to mass flow balancing is required, such that the systematic risk of TCS in all environmental matrices are evaluated. From the perspective of Substance Flow Analysis (SFA), this review critically summarizes the current state of knowledge on TCS production, consumption, discharge, occurrence in built and natural environments, its exposure and metabolism in humans, and also the negative effects of TCS on biota and humans. Recent risk concerns have mainly focused on TCS removal efficiencies and metabolism, but less attention is given to the effect of mass flows from source to fate during risk exposure. However, available data for TCS SFA is limited but SFA can derive logical systematic information from limited data currently available for systematic risk assessment and reduction, based on mass flow analysis. In other words, SFA tool can be used to develop a comprehensive flow chart and indicator system for the risk assessment and reduction of TCS flows in the anthroposphere, thereby bridging knowledge gaps to streamline uncertainties related to policy-making on exposure pathways within TCS flow-lines. In the final analysis, specifics on systematic TCS risk assessment via SFA, and areas of improvement on human adaptation to risks posed by emerging contaminants are identified and directions for future research are suggested.

Stanford's Outcomes Research in Kids (STORK): a prospective study of healthy pregnant women and their babies in Northern California

PURPOSE

Stanford's Outcomes Research in Kids (STORK) is an ongoing prospective cohort of healthy pregnant women and their babies established to determine the effect of infectious diseases on weight, linear growth and immune system development during childhood. Additionally, a nested randomised intervention of household and personal cleaning products tests the effects of the microbicides triclosan and triclocarban on these outcomes and incidence of infection.

PARTICIPANTS

Healthy pregnant women were identified and enrolled primarily at public clinics; their babies, enrolled shortly after birth, are followed to age 36 months. Automated weekly surveys assess daily health status, infectious disease symptoms, healthcare provider visits and antibiotic use, in the mother during pregnancy and the baby once born. At 4-monthly household visits, information and samples are collected from the mother (urine, stool, saliva, skin swab), the baby (blood by heel/toe stick, urine, stool, saliva, skin swab) and the household (environmental swabs). Annual blood samples are obtained by venipuncture (mother and baby). Medical charts are abstracted for allergy and infectious illness in the mother during pregnancy and the baby.

FINDINGS TO DATE

From 7/2011 to 2/2015, 158 mothers were enrolled at approximately 20 weeks gestation; 127 babies were enrolled. Two-thirds of mothers are Hispanic, one-third are non-US born and one-third speak primarily Spanish; mean years of education is 13 (SD 6.2) years. Households have on average 4.5 residents. Most households (97%) were randomised to participate in the intervention. Completion of weekly surveys (86%) and follow-up (75% after 14 months) is excellent in this young, mobile population; collection of samples is ongoing with thousands of specimens stored.

FUTURE PLANS

Enrolled babies will be followed until age 36 months (last anticipated visit: 07/2018) with medical chart review completed soon thereafter. All epidemiological information and samples will be available for collaborative hypothesis testing.

TRIAL REGISTRATION NUMBER

NCT01442701; Pre-results.

Triclosan and bisphenol a affect decidualization of human endometrial stromal cells

In recent years, impaired fertility and endometrium related diseases are increased. Many evidences suggest that environmental pollution might be considered a risk factor for endometrial physiopathology. Among environmental pollutants, endocrine disrupting chemicals (EDCs) act on endocrine system, causing hormonal imbalance which, in turn, leads to female and male reproductive dysfunctions. In this work, we studied the effects of triclosan (TCL) and bisphenol A (BPA), two widespread EDCs, on human endometrial stromal cells (ESCs), derived from endometrial biopsies from woman not affected by endometriosis. Cell proliferation, cell cycle, migration and decidualization mechanisms were investigated. Treatments have been performed with both the EDCs separately or in presence and in absence of progesterone used as decidualization stimulus. Both TCL and BPA did not affect cell proliferation, but they arrested ESCs at G2/M phase of cell cycle enhancing cell migration. TCL and BPA also increased gene expression and protein levels of some decidualization markers, such as insulin growth factor binding protein 1 (IGFBP1) and prolactin (PRL), amplifying the effect of progesterone alone. All together, our data strongly suggest that TCL and BPA might alter human endometrium physiology so affecting fertility and pregnancy outcome.

Triclosan and prescription antibiotic exposures and enterolactone production in adults

BACKGROUND

The gut microbiome plays an important role in the development of disease. The composition of the microbiome is influenced by factors such as mode of delivery at birth, diet and antibiotic use, yet the influence of environmental chemical exposures is largely unknown. The antimicrobial compound triclosan, found in many personal care products and widely detected in human urine, is an environmental exposure for which systemic microbiotic effects may be of particular interest. To investigate the relationship between triclosan and gut microflora, we assessed the association between triclosan and enterolactone, an intestinal metabolite that is produced via bacterial transformation of dietary lignans (seeds, nuts) and has known susceptibility to oral antibiotics.

METHODS

We examined urinary triclosan and enterolactone for 2005-2008 U.S. National Health and Nutrition Examination Survey subjects, aged ≥20 years (n=3041). We also examined the association between prescription antibiotic use and enterolactone to confirm its susceptibility to changes in bacterial composition of the body. Associations between natural log-transformed enterolactone and (1) detected vs. not detected (<2.3 ng/mL) triclosan, (2) triclosan quintiles (Q1-Q5), and (3) any vs. no antibiotics were estimated with multiple linear regression, adjusting for sex, age, race, body mass index, poverty income ratio, education, fiber intake, bowel movement frequency, cotinine and creatinine (n=2441).

RESULTS

Triclosan was detected in 80% of subjects (range: <2.3-3620 ng/mL), while enterolactone was detected in >99% of subjects (range: <0.1-122,000 ng/mL). After adjustment, enterolactone was not associated with triclosan (detect vs. non-detect: β= 0.07 (95% CI: -0.15, 0.30); Q5 (≥104.5 ng/mL) vs. Q1 (none): β= 0.06 (95% CI: -0.21, 0.34)). In sex-stratified analyses, triclosan was associated with higher enterolactone in women (detect vs. non-detect: β= 0.31 (95% CI: -0.07, 0.70), but not men β= -0.18 (95% CI: -0.47, 0.11). However, any antibiotic use (n=112), as compared to no antibiotic use, was associated with significantly lower enterolactone (β=-0.78 (95%CI: -1.22, -0.36)), with no sex-specific effects. This association was driven by inverse associations with the following antibiotic classes: macrolide derivatives, quinolones, sulfonamides, and lincomycin derivatives.

CONCLUSIONS

Antibiotics, but not triclosan, are negatively associated with urinary enterolactone. Antibiotics may reduce enterolactone by killing certain gut bacteria. At levels detected in the U.S., triclosan does not appear to be acting similarly, despite broad antimicrobial properties. Additional study of determinants of triclosan exposure and enterolactone production may be needed to better understand positive associations among women.

Antiseptic mouthwashes could worsen xerostomia in patients taking polypharmacy

OBJECTIVE

Polypharmacy is a common cause of xerostomia. This study aimed to investigate whether xerostomia could be an adverse drug event of mouthwashes, when they are used for longer than 2 weeks by patients taking polypharmacy.

MATERIALS AND METHODS

This cross-sectional observational study included 120 hospitalized patients (60 middle-aged and 60 elderly patients), taking polypharmacy (≥4 drugs daily) and at risk of drug-induced xerostomia. Xerostomia was assessed by questioning participants.

RESULTS

A total of 62.5% of patients complained of xerostomia. In the middle-aged group (mean age=44.0 (8.7) years; 35.0% women) xerostomia seemed independently associated to mouthwashes, at the limit of significance (OR=5.00, 95% CI=0.99-25.3, p=0.052). Active principles in mouthwashes were mainly quaternary ammonium compounds (91.9%). Mouthwashes may disturb the healthy balance of the biofilm moisturizing the oral mucosa. The biofilm contains mucins, salivary glycoproteins with oligosaccharides side chains able to sequester water and endogenous bacteria surrounded by a glycocalyx. Oral bacteria are fully susceptible to quaternary ammonium (chlorhexidine, hexetidine, cetylpyridinium chloride) and to other antiseptics used in mouthwashes, such as betain, resorcin, triclosan, essential oils and alcohol. However, caregivers currently recommend such dental plaque control products to patients suffering from xerostomia in order to reduce the risk of caries and periodontitis.

CONCLUSION

This study is the first report that use of antiseptic mouthwashes for more than 2 weeks could worsen xerostomia in patients taking polypharmacy. Oral care protocols should avoid this iatrogenic practice, particularly when xerostomia alters the quality-of-life and worsens malnutrition.

Investigations of immunotoxicity and allergic potential induced by topical application of triclosan in mice

Triclosan is an antimicrobial chemical commonly used occupationally and by the general public. Using select immune function assays, the purpose of these studies was to evaluate the immunotoxicity of triclosan following dermal exposure using a murine model. Triclosan was not identified to be a sensitizer in the murine local lymph node assay (LLNA) when tested at concentrations ranging from 0.75-3.0%. Following a 28-day exposure, triclosan produced a significant increase in liver weight at concentrations of ≥ 1.5%. Exposure to the high dose (3.0%) also produced a significant increase in spleen weights and number of platelets. The absolute number of B-cells, T-cells, dendritic cells and NK cells were significantly increased in the skin draining lymph node, but not the spleen. An increase in the frequency of dendritic cells was also observed in the lymph node following exposure to 3.0% triclosan. The IgM antibody response to sheep red blood cells (SRBC) was significantly increased at 0.75% - but not at the higher concentrations - in the spleen and serum. These results demonstrate that dermal exposure to triclosan induces stimulation of the immune system in a murine model and raise concerns about potential human exposure.

The influence of a triclosan toothpaste on adverse events in patients with cardiovascular disease over 5-years

Adverse effects of long-term usage of triclosan-containing toothpaste in humans are currently unknown. We assessed the effect of long-term use of 0.3% triclosan-toothpaste on serious adverse events (SAEs) in patients with cardiovascular disease (CVD). 438 patients with a history of stable CVD were entered into the 5-year longitudinal Cardiovascular and Periodontal Study at Prince Charles Hospital, Brisbane, Australia and randomised into test (triclosan) or placebo groups. There were no significant differences in demographics or clinical features between the groups. Patients were examined at baseline, and annually for 5-years. SAEs were classified according to the System Organ Classes defined by MedDRA (Medical Dictionary for Regulatory Activities). Results were analysed using chi square and Kaplan Meier analysis. Overall, 232 patients (123 in the triclosan group; 109 in the placebo group) experienced 569 SAEs (288 in the triclosan group and 281 in the placebo group). There was no significant difference between the groups in numbers of patients experiencing SAEs (p=0.35) or specific cardiovascular SAEs (p=0.82), nor in time to the first SAE or first cardiovascular SAE, irrespective of gender, age or BMI after adjusting for multiple comparisons (p>0.05). The adjusted odds of experiencing an SAE were estimated to increase by 2.7% for each year of age (p=0.02) and the adjusted odds of experiencing a cardiovascular SAE were estimated to increase by 5.1% for each unit increase in BMI (p=0.02). Most cardiovascular events were related to unstable angina or myocardial infarcts, 21 were associated with arrhythmia and 41 were vascular events such as aortic aneurysm and cerebrovascular accident. Within the limitations of the present study the data suggest that the use of triclosan-toothpaste may not be associated with any increase in SAEs in this CVD population. The long-term impact of triclosan on hormone-related disease, such as cancer, in humans remains to be determined.

Cytogenetic analysis of oral mucosa cells, induced by chlorhexidine, essential oils in ethanolic solution and triclosan mouthwashes

OBJECTIVES

The aim of this study was to evaluate DNA damage and cytokinetic defects, proliferative potential and cell death caused by the frequent use of mouthrinses containing chlorhexidine, triclosan and essential oils in ethanolic solution, compared to a placebo mouthwash.

STUDY DESIGN

This double-blind, prospective, randomized clinical trial included 80 Caucasian patients. Subjects were divided into four groups: Group I used a mouthrinse, Triclosan; Group II used physiological saline; Group III used chlorhexidine; Group IV a mouthrinse with essential oils in ethanolic solution. All subjects used the mouthrinses for two weeks (15 ml, twice a day, rinsing for 30s). Two cell samples per subject were collected, before and after mouthrinse use (on day 0 and day 15). Samples were processed as follows: cell collection from cheeks with a cytobrush; cell centrifuge; slide preparation, fixation and staining; and fluorescent microscope analysis. 2000 exfoliated cells were screened for nuclear abnormalities, particularly the presence of micronuclei by means of cytome assay.

RESULTS

No significant differences between study times (before and after use of mouthwash) were identified for any of the variables studied (p>0.05). Differences between mouthrinse groups were also compared but no significant differences were found (p>0.05).

CONCLUSIONS

This study did not observe any genotoxic effect resulting from mouthrinse use.

Update on antibacterial soaps: the FDA takes a second look at triclosans

In December of 2013 the Food and Drug Administration announced it would look further into the safety and efficacy of the biocide triclosan and requested further safety data as part of a new review with the Environmental Protection Agency. The use of triclosan has increased exponentially since its introduction in in 1972, to the point that 75% of commercial soap brands contain triclosan and 76% of a nationwide sample of adults and children excrete triclosan in the urine. This announcement raised an important dialog about the appropriate use of all over the counter biocides. Particular concerns include whether these biocides are more effective than regular soaps, whether they may create new drug resistant bacteria, and whether they may also act as hormone disruptors in humans or the environment.

Effectiveness of a mouthrinse containing active ingredients in addition to chlorhexidine and triclosan compared with chlorhexidine and triclosan rinses on plaque, gingivitis, supragingival calculus and extrinsic staining

OBJECTIVES

To assess the effectiveness of three different mouthrinses--chlorhexidine, triclosan + sodium fluoride and chlorhexidine + triclosan + sodium fluoride + zinc chloride--on plaque, calculus, gingivitis and stains and to evaluate the occurrence of adverse effects with these three treatments.

METHODS

Forty-eight healthy subjects participated in a double-blind, randomized, parallel experiment and were randomly allocated to any one of the three experimental mouthrinses: group A (0.2% chlorhexidine (CHX) gluconate), group B (0.03% triclosan + 0.025% sodium fluoride (NaF) + 12% ethyl alcohol) or group C (0.2% CHX + 0.3% triclosan + 0.3% NaF + 0.09% Zn chloride (ZnCl(2)). All the subjects were assessed for gingivitis, plaque, supragingival calculus and extrinsic stains at baseline and at the end of the 21-day experimental period.

RESULTS

There was a significant difference (P = 0.046) in the effectiveness for the prevention of gingivitis and plaque, with subjects of group A and group C presenting least and highest gingival and plaque scores, respectively. Significant differences (P = 0.03) were observed for the accumulation of supragingival calculus where the deposition of calculus in group A was nearly double that of the group B, and group B was most effective in the prevention of supragingival calculus. Highest deposition of extrinsic stains was in the group A followed by group C and group B. There was no significant difference between the three treatments for adverse events' occurrence.

CONCLUSIONS

CHX mouthrinse was most effective in controlling plaque and gingivitis but caused greatest deposition of extrinsic stains. Supragingival calculus deposition was least in triclosan + NaF group followed by CHX + triclosan + NaF + ZnCl(2) and CHX. More than half of the subjects reported adverse events during the experimental phase.

Triclosan, an environmental pollutant from health care products, evokes charybdotoxin-sensitive hyperpolarization in rat thymocytes

The effects of triclosan, an environmental pollutant from household items and health care products, on membrane potential and intracellular Ca(2+) concentrations of rat thymocytes were examined by a flow cytometry with fluorescent probes, di-BA-C(4) and fluo-3-AM, because triclosan is often found in humans and wild animals. Triclosan at a concentration of 3 μM decreased the intensity of di-BA-C(4) fluorescence, indicating the triclosan-induced hyperpolarization. The application of charybdotoxin, a specific inhibitor of Ca(2+)-dependent K(+) channels, and the removal of external Ca(2+) eliminated the triclosan-attenuation of di-BA-C(4) fluorescence. Furthermore, triclosan augmented the fluo-3 fluorescence under normal Ca(2+) condition, indicating that triclosan increased intracellular Ca(2+) concentration. These results suggest that triclosan induces membrane hyperpolarization by increasing intracellular Ca(2+) concentration that activates Ca(2+)-dependent K(+) channels. Since the change in membrane potential of lymphocytes influence cellular immune functions, triclosan may exert adverse actions on immune system in human and wild animals.

Triclosan antagonizes fluconazole activity against Candida albicans

Triclosan is a broad-spectrum antimicrobial compound commonly used in oral hygiene products. Investigation of its activity against Candida albicans showed that triclosan was fungicidal at concentrations of 16 mg/L. However, at subinhibitory concentrations (0.5-2 mg/L), triclosan antagonized the activity of fluconazole. Although triclosan induced CDR1 expression in C. albicans, antagonism was still observed in cdr1Δ and cdr2Δ strains. Triclosan did not affect fluconazole uptake or alter total membrane sterol content, but did induce the expression of FAS1 and FAS2, indicating that its mode of action may involve inhibition of fatty acid synthesis, as it does in prokaryotes. However, FAS2 mutants did not exhibit increased susceptibility to triclosan, and overexpression of both FAS1 and FAS2 alleles did not alter triclosan susceptibility. Unexpectedly, the antagonistic effect was specific for C. albicans under hypha-inducing conditions and was absent in the non-filamentous efg1Δ strain. This antagonism may be due to the membranotropic activity of triclosan and the unique composition of hyphal membranes.

Triclosan and thyroid-mediated metamorphosis in anurans: differentiating growth effects from thyroid-driven metamorphosis in Xenopus laevis

In a previously reported study, we used a standard metamorphosis anuran model to assess potential effect of the antibacterial agent triclosan (TCS) on normal prometamorphic Xenopus laevis. Results indicated that environmentally relevant TCS concentrations did not alter the normal course of thyroid-mediated metamorphosis in this standard anuran model. However, to examine potential effects of TCS exposure during premetamorphosis and to distinguish between effects on metamorphosis and effects on growth, a longer term TCS exposure study was conducted. Standard Nieuwkoop and Faber (NF) stage 47 X. laevis larvae were exposed for 32 days (ca. NF stage 59-60) via flow-through to four different concentrations of TCS: < 0.2 (control), 0.8, 3.1, 12.5, or 50.0 μg TCS/l. Primary endpoints were survival, hind limb length, body length (whole; snout-to-vent), developmental stage, wet whole body weight, thyroid histology, plasma thyroid hormone (TH) concentrations, TH receptor beta (TRβ), and type II and III deiodinase (DI-2 and DI-3) expression. Endpoints measured to evaluate effects on thyroid-mediated metamorphosis including developmental stage, thyroid histology, TRβ expression, DI-2 and DI-3 expression, and thyroid gland 3,5,3',5'-tetraiodothyronine (T4) and plasma T4 and 3,5,3'-triiodothyronine (T3) levels were not affected by TCS exposure. However, increased larval growth based on whole body length (0.78, 12.5, and 50 μg TCS/l), snout-vent length (3.1 and 12.5 μg TCS/l), and whole body weight (0.8, 12.5, and 50.0 μg TCS/l) was observed following 32-day TCS exposure. These results indicated that TCS exposure during pre- and prometamorphosis increased larval growth but did not alter the normal course of metamorphosis in X. laevis. The increased growth associated with TCS exposure was not unexpected and is generally consistent with the presence of reduced bacterial stressors in culture.