Prenatal airborne polycyclic aromatic hydrocarbon exposure, LINE1 methylation and child development in a Chinese cohort.

BACKGROUND: Polycyclic aromatic hydrocarbons (PAH) are carcinogenic, neurotoxic environmental pollutants generated during incomplete combustion of fossil fuel and other organic material. PAH exposure has been associated with adverse fetal development and epigenetic alterations in cord blood. Several molecular epidemiology studies have established PAH-DNA adducts as biomarkers of PAH exposure. OBJECTIVES: We investigated the relationship between LINE1 DNA methylation and PAH-DNA adduct levels in cord blood, and with neurodevelopmental outcomes. METHODS: In Tongliang County, China, the current study enrolled two population-based cohorts of nonsmoking pregnant women before (2002) and after (2005) the closure of a local coal-fired power plant in May 2004. We analyzed cord blood samples collected from mothers in the two cohorts (n=110 from 2002 cohort and n=107 from 2005 cohort) for PAH-DNA adducts and genomic LINE1 DNA methylation. Neurodevelopmental data on children were collected using the Gesell Developmental Scales (GDS) at age 2 and using the Wechsler Intelligence Scale for Children (WISC) at age 5. RESULTS: A significant inverse relationship was observed between PAH-DNA adducts and LINE1 DNA methylation (ß=-0.010, p<0.038). A significant, positive association between LINE1 methylation and scores on WISC full scale and verbal (ß=85.31, p<0.005; ß=94.36, p<0.003) but not on the GDS. Mediation analysis did not find LINE1 to be a direct mediator between PAH-DNA adducts and IQ score. CONCLUSION: LINE1 methylation in cord blood DNA was a positive predictor of IQ at age 5 and was decreased at higher levels of prenatal PAH exposure measured by PAH-DNA adducts in cord blood. However, the adverse effects of prenatal exposure to PAH on IQ scores did not appear to be directly mediated by altered LINE1 methylation.

Air pollution effects on fetal and child development: a cohort comparison in China.

In Tongliang, China, a coal-fired power plant was the major pollution source until its shutdown in 2004. We enrolled two cohorts of nonsmoking women and their newborns before and after the shutdown to examine the relationship between prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) and fetal and child growth and development. PAHs were used to measure exposure to air pollution generated by the power plant. Using PAH-DNA adduct levels as biomarkers for the biologically effective dose of PAH exposure, we examined whether PAH-DNA adduct levels were associated with birth outcome, growth rate, and neurodevelopment. Head circumference was greater in children of the second cohort, compared with the first (p = 0.001), consistent with significantly reduced levels of cord blood PAH-DNA adducts in cohort II (p < 0.001) and reduced levels of ambient PAHs (p = 0.01).

[Fetal circulation in relation to various maternal body positions].

To determine the possible effect of various maternal body position on feto-maternal circulation, we performed Doppler examinations on 50 women at different stages between the 27th and 40th week of normal pregnancy. Flow velocity waveforms of the umbilical artery, fetal descending aorta, and maternal uterine artery were recorded by pulsed Doppler scanner equipped with a 3.5MHz transducer (ALOKA SSD 680). The resistance index (RI) was calculated with the patient lying initially in the supine position, then 15 minutes later, in the lateral recumbent position. Maternal blood pressure, placental site, and fetal position were also assessed for possible relationship with the maternal position reflected by the resistance indices. The following results were obtained: (1) a negative correlation was observed between gestational period and umbilical artery flow velocity (r = -0.404, P < 0.05). (2) although up to the 37th week no outstanding difference was noted in the effect of maternal position on the flow velocity of the uterine and umbilical artery, from weeks 37 to 40, the resistance indices recorded in the supine position were significantly higher than those associated with the lateral recumbent position (P < 0.05). In the lateral recumbent position. Flow velocity of the umbilical artery was consistently in close correlation with that of the uterine artery. However maternal position had no bearing on the flow velocity in the fetal descending aorta; (3) no significant relationship was indicated between the flow velocity of the umbilical artery and blood pressure, placental site or fetal position.(ABSTRACT TRUNCATED AT 250 WORDS)