Organophosphorous and organochlorine pesticides affect human placental phosphoinositides metabolism and PI-4 kinase activity

Feasibility of using low density polyethylene sheets to detect atmospheric organochlorine pesticides in Alexandria, Egypt

Egypt is a major agricultural country in Africa with a known past of organochlorine pesticides (OCPs) application, yet data on atmospheric levels of OCPs in Egypt is sparse. Low density polyethylene (LDPE) passive samplers were therefore deployed for 3 weeks each at 11 locations in July, 2010 and January, 2011 in Alexandria to screen for gas-phase OCPs. Performance reference compounds were used to investigate the uptake kinetics. Field-derived sampler-air partitioning coefficients (KPE-As) for OCPs were significantly correlated against the compounds' subcooled liquid vapor pressure (log PL): [log KPE-A = -0.77 ± 0.07 log PL + 6.35 ± 0.13 (R(2) = 0.90; n = 17; SE = 0.19; p < 0.001)]. Estimated and measured OCP concentrations in Alexandria agreed well (factor difference ≤ 2) indicating the feasibility of monitoring OCPs using LDPEs. OCP concentrations ranged from <LOD to 168 pg/m(3). Calculated isomeric ratios indicated recent usage of chlordanes and endosulfans.

Maternal exposure to the mixture of organophosphorus pesticides induces reproductive dysfunction in the offspring

Organophosphorus pesticide residues are found in many food samples due to increasing use of multiple organophosphorus pesticides (OPs) in agriculture. Toxicity of individual organophosphorus has been well-studied in previous epidemiological and laboratory investigations. This study focused on reproductive toxicity of perinatal exposure to the mixture of organophosphorus pesticides (MOPs). The MOPs consists of three most commonly used pesticides, i.e., Dichlorovos, Dimethoate, and Malathion which individually does not cause significant effects on the reproductive system at the similar concentration levels based on previous studies. Using the Sprague-Dawley rats, we established a perinatal exposure model by oral gavage and observed significant endometrial hyperplasia and thickened uterine walls in the F0 rats after administration of high doses of the MOPs. We further monitored several key developmental and behavioral indices in the F1 generation after maternal exposure to the MOPs, and observed significantly delayed physical development and weakened mental development. Moreover, we found increased weights of the reproductive organs (the uterus and the testis) and abnormal levels of key sex hormones (progestin and testosterone) in the MOPs groups. It is more important that we observed a significantly lower pregnancy rate and live birth rate in the high-dose MOPs group. These results indicate that the MOPs may be more detrimental to the maternal endometria and the reproductive functions in the offspring than individual organophosphorus.

Prenatal exposure to pesticides: analysis of human placental acetylcholinesterase, glutathione S-transferase and catalase as biomarkers of effect

Pre- and perinatal exposure to pesticides is deleterious on foetal and neonatal development, but information regarding possible effects on environmental low-dose exposure to pesticides is scarce. Most epidemiological studies of the health effect of pesticides have been based on self-reported information. However, detailed information on past pesticide use is difficult to reconstruct. This is a current study conducted among pregnant mothers attending a delivery care and perinatal programme at a public hospital. The study investigates biomarkers of early effects in placentas from women living in an area with an intensive use of pesticides in the northern part of Patagonia, province of Río Negro, Argentina, and it assesses the consistency of the information provided by self-reports. The study confirms that placental acetylcholinesterase and catalase activities are significantly associated with periods of organophosphorus pesticides application, while glutathione S-transferase is not affected. We found a positive correlation between environmental exposure to organophosphorus pesticides and carbamate insecticides and newborn head circumference. The findings provide a further indication of a link between placenta acetylcholinesterase and catalase activity and prenatal exposure to pesticides in population studies. Both placenta enzymes may be used as biomarkers in health surveillance programmes for early diagnosis of exposure related alterations produced by organophosphorus pesticides and carbamate pesticides.

Characterization of chlorpyrifos-induced apoptosis in placental cells

The mechanism by which chlorpyrifos exerts its toxicity in fetal and perinatal animals has yet to be elucidated. Since the placenta is responsible for transport of nutrients and is a major supplier hormone to the fetus, exposure to xenobiotics that alter the function or viability of placenta cells could ostensibly alter the development of the fetus. In this study, JAR cells were used to determine if CPF and the metabolites 3,5,6-trichloro-2-pyridinol (TCP) and chlorpyrifos-oxon (CPO) are toxic to the placenta. Our results indicate that chlorpyrifos (CPF), and its metabolite chlorpyrifos-oxon (CPO) caused a dose-dependent reduction in cellular viability with CPF being more toxic than its metabolites. Chlorpyrifos-induced toxicity was characterized by the loss of mitochondrial potential, the appearance of nuclear condensation and fragmentation, down-regulation of Bcl-2 as well as up-regulation of TNFalpha and FAS mRNA. Pharmacological inhibition of FAS, nicotinic and TNF-alpha receptors did not attenuate CPF-induced toxicity. Atropine exhibited minimal ability to reverse toxicity. Furthermore, signal transduction inhibitors PD98059, SP600125, LY294002 and U0126 failed to attenuate toxicity; however, SB202190 (inhibitor of p38alpha and p38beta MAPK) sensitized cells to CPF-induced toxicity. Pan-caspase inhibitor Q-VD-OPh produced a slight but significant reversal of CPF-induced toxicity indicating that the major caspase pathways are not integral to CPF-induced toxicity. Taken collectively, these results suggest that chlorpyrifos induces apoptosis in placental cells through pathways not dependent on FAS/TNF signaling, activation of caspases or inhibition of cholinesterase. In addition, our data further indicates that activation of p38 MAPK is integral to the protection cells against CPF-induced injury.

Organophosphate levels in apple composites and individual apples from a treated Canadian orchard

Azinphos-methyl, phosalone, and phosmet were applied individually to separate rows of trees within a commercial apple orchard in Quebec, Canada, during the 2003 agricultural season. Apples were collected for residue analysis immediately prior to the harvesting of the remaining apples for market distribution and were prepared for analysis as both individual apples and as composites of eight individuals. Analysis of the three applied compounds, as well as five organophosphate insecticides that were not applied, was performed using gas chromatography-mass spectrometry. Azinphos-methyl, phosalone, and phosmet, which were applied, were detected in all samples analyzed at concentrations ranging from 0.004 ng/g to 2260 ng/g. Methidathion was not observed in any sample. Chlorpyrifos, diazinon, dimethoate, and malathion concentrations ranged from below method detection limits to 0.71 ng/g, and the detection frequency for these compounds ranged from 20% to 100%. Residues measured in this study were all below the Canadian maximum residue limit for apples. Variability factors ranged from 2 to 19 for all compounds observed in this study. Composite samples may not accurately reflect the extremes of exposure from consumption of single servings of apples.