Cigarette exposure induces changes in maternal vascular function in a pregnant mouse model
Smoking is associated with multiple adverse pregnancy outcomes, including fetal growth restriction. The objective of this study was to determine whether cigarette smoke exposure during pregnancy in a mouse model affects the functional properties of maternal uterine, mesenteric, and renal arteries as a possible mechanism for growth restriction. C57Bl/CJ mice were exposed to whole body sidestream smoke for 4 h/day. Smoke particle exposure was increased from day 4 of gestation until late pregnancy (day 16-19), with mean total suspended particle levels of 63 mg/m(3), representative of moderate-to-heavy smoking in humans. Uterine, mesenteric, and renal arteries from late-pregnant and virgin mice were isolated and studied in a pressure-arteriograph system (n = 23). Plasma cotinine was measured by ELISA. Fetal weights were significantly reduced in smoke-exposed compared with control fetuses (0.88 +/- 0.1 vs. 1.0 +/- 0.08 g, P < 0.02), while litter sizes were not different. Endothelium-mediated relaxation responses to methacholine were significantly impaired in both the uterine and mesenteric vasculature of pregnant mice exposed to cigarette smoke during gestation. This difference was not apparent in isolated renal arteries from pregnant mice exposed to cigarette smoke; however, relaxation was significantly reduced in renal arteries from smoke-exposed virgin mice. In conclusion, we found that passive cigarette smoke exposure is associated with impaired vascular relaxation of uterine and mesenteric arteries in pregnant mice. Functional maternal vascular perturbations during pregnancy, specifically impaired peripheral and uterine vasodilation, may contribute to a mechanism by which smoking results in fetal growth restriction.
Available from: Asta Danileviciute
- "The main factors influencing birth-weight reduction are gestational age and the organism’s response to toxicity from environmental xenobiotics, such as tobacco PAHs. Tobacco smoke toxins impair placental vasculature function and subsequent transplacental transport of oxygen and nutrients, and may lead to changes in vascular resistance
[39,40]. Reduction in blood flow increase apoptosis and it is possible that this could be one of the mechanisms playing a role in the growth restriction
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Genetic susceptibility to tobacco smoke might modify the effect of smoking on pregnancy outcomes.
We conducted a case–control study of 543 women who delivered singleton live births in Kaunas (Lithuania), examining the association between low-level tobacco smoke exposure (mean: 4.8 cigarettes/day) during pregnancy, GSTT1 and GSTM1 polymorphisms and birthweight of the infant. Multiple linear-regression analysis was performed adjusting for gestational age, maternal education, family status, body mass index, blood pressure, and parity. Subsequently, we tested for the interaction effect of maternal smoking, GSTT1 and GSTM1 genes polymorphisms with birthweight by adding all the product terms in the regression models.
The findings suggested a birthweight reduction among light-smoking with the GSTT1–null genotype (−162.9 g, P = 0.041) and those with the GSTM1–null genotype (−118.7 g, P = 0.069). When a combination of these genotypes was considered, birthweight was significantly lower for infants of smoking women the carriers of the double-null genotypes (−311.2 g, P = 0.008). The interaction effect of maternal smoking, GSTM1 and GSTT1 genotypes was marginally significant on birthweight (−234.5 g, P = 0.078). Among non-smokers, genotype did not independently confer an adverse effect on infant birthweight.
The study shows the GSTT1–null genotype, either presents only one or both with GSTM1–null genotype in a single subject, have a modifying effect on birthweight among smoking women even though their smoking is low level. Our data also indicate that identification of the group of susceptible subjects should be based on both environmental exposure and gene polymorphism. Findings of this study add additional evidence on the interplay among two key GST genes and maternal smoking on birth weight of newborns.
Available from: ncbi.nlm.nih.gov
- "Of note, our analysis also detected a low-level of cotinine in the serum, but not the placental tissues, of the nonsmoking adult mice. The concentration of serum cotinine in these animals was very low, near the limits of detection of our assay, and corresponded to similar findings reported in other rodent models [47,48]. The source of cotinine in the nonsmoking mice is not clear, however, it is possible that it may be a dietary source and/or vitamin supplement – niacin has been reported to cross-react with cotinine assays, and low levels of nicotine have been demonstrated in some none-tobacco plants [49,50]. "
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ABSTRACT: Maternal smoking is a risk factor for pediatric lung disease, including asthma. Animal models suggest that maternal smoking causes defective alveolarization in the offspring. Retinoic acid signaling modulates both lung development and postnatal immune function. Thus, abnormalities in this pathway could mediate maternal smoking effects. We tested whether maternal smoking disrupts retinoic acid pathway expression and functioning in a murine model.
Female C57Bl/6 mice with/without mainstream cigarette smoke exposure (3 research cigarettes a day, 5 days a week) were mated to nonsmoking males. Cigarette smoke exposure continued throughout the pregnancy and after parturition. Lung tissue from the offspring was examined by mean linear intercept analysis and by quantitative PCR. Cell culture experiments using the type II cell-like cell line, A549, tested whether lipid-soluble cigarette smoke components affected binding and activation of retinoic acid response elements in vitro.
Compared to tobacco-naïve mice, juvenile mice with tobacco toxin exposure had significantly (P < 0.05) increased mean linear intercepts, consistent with an alveolarization defect. Tobacco toxin exposure significantly (P < 0.05) decreased mRNA and protein expression of retinoic acid signaling pathway elements, including retinoic acid receptor alpha and retinoic acid receptor beta, with the greatest number of changes observed between postnatal days 3-5. Lipid-soluble cigarette smoke components significantly (P < 0.05) decreased retinoic acid-induced binding and activation of the retinoic acid receptor response element in A549 cells.
A murine model of maternal cigarette smoking causes abnormal alveolarization in association with altered retinoic acid pathway element expression in the offspring. An in vitro cell culture model shows that lipid-soluble components of cigarette smoke decrease retinoic acid response element activation. It is feasible that disruption of retinoic acid signaling contributes to the pediatric lung dysfunction caused by maternal smoking.
Available from: prijipati.library.usyd.edu.au
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