The Impact of Pesticides - Academy Publish

elationship between OP exposure and PON1 C-108T/Q192R polymorphisms asmodulators of birth outcomes was explored by Harley et al. (2011) in Mexican-American women enrolled in the CHAMACOS Study, which comprises a cohort ofmothers and children from Latino farm workers families in the Salinas Valley,California (USA) where OP are applied. Infants with the PON1 -108TT genotypehad shorter gestational age and had smaller head circumference than those with thePON -108CC genotype, while maternal total dialkylphosphates (DAP)concentrations (OP metabolites) were associated with shorter gestational age onlyamong infants carrying the susceptible PON1 -108TT genotype (interactionp = 0.09). In addition, infants’ arylesterase and paraoxonase activities werepositively associated with gestational age.The interaction between maternal exposure to pesticides and the risk for having ababy with low birth weight (LBW) was also evaluated by Moreno-Banda et al.(2009) in a cross-sectional study in 264 female floriculturists or partners offloriculture workers from Central Mexico. Floriculture mothers carrying the PON1192RR genotype showed nearly six-fold higher risk for having a baby with LBW(OR=5.93. 95% IC 1.28-27.5) if working during pregnancy, concluding that PON1genetic variability increases the probability of having children with LBW.In the CHAMACOS Study, Eskenazi et al. (2010) also evaluated the relationshipbetween PON1 and neurodevelopment in children exposed to OP in utero. Childrenwith PON1 -108CT and -108TT genotypes performed lower scores on the BayleyScales of Infant Development than children with the PON1 -108CC genotype.Furthermore, maternal DAP concentrations were negatively associated with Bayley'scores in children with PON1 -108CC or -108CT genotypes. PON Q192R did notshow a clear pattern of associations with this outcome. Engel et al. (2011) evaluatedthe prenatal exposure to OP, PON1 Q192R polymorphism and congnitivedevelopment at 12 and 24 months of age in children of the Mount Sinai Children´sEnvironmental Health Cohort study (404 mother-infant pairs). A negativeassociation between prenatal exposure to OP (by means of DAP anddimethylphosphate (DMP) urine concentrations) and poorer Bayley' scores at 12months was observed among black and Hispanic participants. Children of motherswith the PON1 192QR/RR genotype had approximately a five-point decline onBayley' score with each log 10 unit increase in DAP or DMP levels. By the contrary,latter in childhood, children of mothers with the PON1 192QQ genotype had adecrement in perceptual reasoning score with each log 10 increment in DAP andDMP metabolites, this effect was not observed in children with mothers carrying thePON1 192QR/RR genotypes. An explanation for this contradictory effect is notgiven yet.The relationship among childhood brain tumors (CBT), residential insecticideexposure (mainly chlorpyrifos and diazinon) and PON1 C-108T and Q192Rpolymorphisms was explored by Nielsen et al. (2005) in children enrolled in theU.S. West Coast CBT Study. The risk of CBT was significantly increased amongchildren genotyped as -108T whose mothers referred using pesticides duringpregnancy (the risk per -108T allele, OR=2.6, 95% CI, 1.2-5-5), suggesting thatCBT risk may be inversely related to PON1 protein levels. PON1 Q192R and L55Mpolymorphisms did not show significant interactions (Nielsen et al., 2005, 2010).Authors mentioned that these results must be interpreted with caution due to somelimitations, such as the small sample size, no prior studies and technical problemswith the DNA sampling.Finally, González-Herrera et al. (2010) evaluated PON1 polymorphisms andhaplotypes and the risk for having offspring affected with spina bifida (SB) in a totalof 152 parents of children with open-dorsolumbar SB in Southeast Mexico. Sixty-AcademyPublish.org - The Impact of Pesticides70