Human biomonitoring in Israel: Past, present, future

Investigation of the efficacy of diosmin against organ damage caused by bendiocarb in male Wistar albino rats

Bendiocarb is a carbamate insecticide, which is used more in indoor areas, especially against scorpions, spiders, flies, mosquitoes and cockroaches. Diosmin is an antioxidant flavonoid found mostly in citrus fruits. In this study, the efficacy of diosmin against the adverse effects of bendiocarb was investigated in rats. For this purpose, 60, 2-3 month-old male Wistar albino rats, weighing 150-200 g, were used. The animals were assigned to six groups, one of which was maintained for control purposes and five of which were trial groups. The control rats received only corn oil, which was used as a vehicle for diosmin administration in the trial groups. Groups 2, 3, 4, 5 and 6 were administered with 10 mg/kg.bw bendiocarb, 10 mg/kg.bw diosmin, 20 mg/kg.bw diosmin, 2 mg/kg.bw bendiocarb plus 10 mg/kg.bw diosmin, and 2 mg/kg.bw bendiocarb plus 20 mg/kg.bw diosmin, respectively, using an oral catheter, for 28 days. At the end of the study period, blood and organ (liver, kidneys, brain, testes, heart and lungs) samples were collected. Body weight and organ weights were determined. Compared to the control group, in the group given bendiocarb alone, firstly, body weight and liver, lung and testicular weights decreased. Secondly, tissue/plasma malondialdehyde (MDA) and nitric oxide (NO) levels increased, and glutathione (GSH) levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) (except for lung tissue), glutathione reductase (GR), and glucose-6-phosphate dehydrogenase (G6PD) activities decreased in all tissues and erythrocytes. Thirdly, catalase (CAT) activity decreased in erythrocytes and the kidney, brain, heart and lung tissues and increased in the liver and testes. Fourthly, while GST activity decreased in the kidneys, testes, lung and erythrocytes, an increase was observed in the liver and heart tissues. Fifthly, while serum triglyceride levels and lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and pseudo-cholinesterase (PchE) activities decreased, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and blood urea nitrogen (BUN), creatinine and uric acid levels increased. Lastly, liver caspase 3, caspase 9 and p53 expression levels significantly increased. When compared to the control group, the groups treated with diosmin alone showed no significant difference for the parameters investigated. On the other hand, it was observed that the values of the groups treated with a combination of bendiocarb and diosmin were closer to the values of the control group. In conclusion, while exposure to bendiocarb at a dose of 2 mg/kg.bw for 28 days caused oxidative stress/organ damage, diosmin administration at doses of 10 and 20 mg/kg.bw reduced this damage. This demonstrated that diosmin has pharmaceutical benefits, when used for supportive treatment as well as radical treatment, against the potential adverse effects of bendiocarb.

A Workflow to Investigate Exposure and Pharmacokinetic Influences on High-Throughput in Vitro Chemical Screening Based on Adverse Outcome Pathways

BACKGROUND

Adverse outcome pathways (AOPs) link adverse effects in individuals or populations to a molecular initiating event (MIE) that can be quantified using in vitro methods. Practical application of AOPs in chemical-specific risk assessment requires incorporation of knowledge on exposure, along with absorption, distribution, metabolism, and excretion (ADME) properties of chemicals.

OBJECTIVES

We developed a conceptual workflow to examine exposure and ADME properties in relation to an MIE. The utility of this workflow was evaluated using a previously established AOP, acetylcholinesterase (AChE) inhibition.

METHODS

Thirty chemicals found to inhibit human AChE in the ToxCast™ assay were examined with respect to their exposure, absorption potential, and ability to cross the blood-brain barrier (BBB). Structures of active chemicals were compared against structures of 1,029 inactive chemicals to detect possible parent compounds that might have active metabolites.

RESULTS

Application of the workflow screened 10 "low-priority" chemicals of 30 active chemicals. Fifty-two of the 1,029 inactive chemicals exhibited a similarity threshold of ≥ 75% with their nearest active neighbors. Of these 52 compounds, 30 were excluded due to poor absorption or distribution. The remaining 22 compounds may inhibit AChE in vivo either directly or as a result of metabolic activation.

CONCLUSIONS

The incorporation of exposure and ADME properties into the conceptual workflow eliminated 10 "low-priority" chemicals that may otherwise have undergone additional, resource-consuming analyses. Our workflow also increased confidence in interpretation of in vitro results by identifying possible "false negatives."

CITATION

Phillips MB, Leonard JA, Grulke CM, Chang DT, Edwards SW, Brooks R, Goldsmith MR, El-Masri H, Tan YM. 2016. A workflow to investigate exposure and pharmacokinetic influences on high-throughput in vitro chemical screening based on adverse outcome pathways. Environ Health Perspect 124:53-60; http://dx.doi.org/10.1289/ehp.1409450.

Urinary concentrations of environmental contaminants and phytoestrogens in adults in Israel

BACKGROUND

The Ministry of Health Biomonitoring Study estimated exposure of individuals in the Israeli population to bisphenol A (BPA), organophosphate (OP) pesticides, phthalates, cotinine, polycyclic aromatic hydrocarbons (PAHs), and the phytoestrogenic compounds genistein and daidzein.

METHODS

In 2011, 250 individuals (ages 20-74) were recruited from five different regions in Israel. Urine samples were collected and questionnaire data were obtained, including detailed dietary data (food frequency questionnaire and 24hour recall). Urinary samples were analyzed for BPA, OP metabolites (dialkyl phosphates), phthalate metabolites, cotinine, PAH metabolites, genistein, and daidzein.

RESULTS AND DISCUSSION

BPA urinary concentrations were above the limit of quantification (LOQ) in 89% of the samples whereas urinary concentrations of phthalate metabolites were above the LOQ in 92-100% of the samples. PAH metabolites were above the LOQ in 63-99% of the samples whereas OP metabolites were above the LOQ in 44-100% of the samples. All non-smoking participants had detectable levels of cotinine in their urine; 63% had levels above the LOQ, and the rate of quantification was high compared to the general non-smoking population in Canada. Median creatinine adjusted concentrations of several OP metabolites (dimethyl phosphate, dimethyl thiophosphate) were high in our study population compared to the general US and Canadian populations. Median creatinine adjusted urinary BPA concentrations in the study population were comparable to those in Belgium and Korea; higher than those reported for the general US, German, and Canadian populations; and very low compared to health-based threshold values. Phthalate concentrations were higher in our study population compared to the general US population but values were very low compared to health-based threshold values. Median creatinine adjusted PAH concentrations were generally comparable to those reported for the general US population; median creatinine adjusted daidzein concentrations were high in our population compared to the general US population whereas genistein concentrations were comparable.

CONCLUSIONS

We interpreted observed urinary contaminant levels observed in our study by comparing values with health-based threshold values and/or values from international human biomonitoring studies. Using this data interpretation scheme, we identified two contaminants as being of potential public health concern and high priority for public health policy intervention: environmental tobacco smoke (ETS) and OP pesticides. We used the data collected in this study to support public health policy interventions. We plan to conduct a follow-up biomonitoring study in 2015 to measure ETS and OP exposure in the general population in Israel, to evaluate the effectiveness of relevant policy interventions.

Trends in reproductive health in Israel: implications for environmental health policy

Nearly two decades ago, researchers first reported that endocrine disrupting chemicals in the environment were affecting reproductive health in the general population. The purpose of this article is to examine the evidence of adverse reproductive health trends in Israel and to explore implications for environmental health policy in Israel. We reviewed studies and data in Israel regarding trends in reproductive health indices, specifically: breast and testis cancer, hypospadias, sperm quality, male factor infertility, and age at menarche. The data provide some evidence of adverse reproductive trends in the Israeli population: an increase in testicular cancer from 1990 to 2007, a decrease in age at menarche from 1986 to 2000, an increase in the prevalence of male factor infertility, and some evidence of decreasing sperm counts. However, we note that much of the evidence is limited.The policy implications of reported adverse reproductive health trends possibly related to environmental exposure have been radically different in Europe and the United States. In Europe, such reports led the Parliament of the European Community to adopt a resolution on endocrine disruptors, which emphasizes the application of the Precautionary Principle. U.S. Environmental Protection Agency policy is focused on screening chemicals for endocrine disrupting properties and does not specifically refer to the Precautionary Principle. To date, there has been no formal governmental policy or strategy in Israel regarding endocrine disrupting chemicals. Environmental health policy on endocrine disruptors requires integrating evidence on human reproductive health trends, evidence on adverse reproductive outcomes in wildlife and experimental systems, and data from biomonitoring studies. Despite gaps in evidence and current data, we support a precautionary approach to regulating potential endocrine disrupting chemicals and reducing public exposures, especially in sensitive groups such as children and pregnant women.