Maternal smoking has a severe negative effect on all stages of pregnancy that in consequence impairs fetal growth and development. Tobacco smoke-related defects are well established at the clinical level; however, little is known about molecular mechanisms underlying these pathological conditions. We thus employed a genomic approach to determine transcriptome alterations induced by maternal smoking in pregnancy. We assayed gene expression profiles in peripheral blood (M) leukocytes and placentas (PL) of pregnant smokers and those without significant exposure, and in cord blood (D) leukocytes of their babies. Comparative analyses defined significant deregulation of 193 genes in M cells, 329 genes in placentas, and 49 genes in D cells of smokers. These genes were mainly involved in xenobiotic metabolism, oxidative stress, inflammation, immunity, hematopoiesis, trophoblast differentiation, and vascularization. Functional annotation of the deregulated genes outlined processes and pathways affected by tobacco smoke. In smoker newborns, we identified several deregulated pathways associated with autoimmune diseases. The study demonstrates a limited ability of placenta to modulate toxic effects of maternal tobacco use at the gene expression level.

Blood and placental samples were obtained from 91 women who gave birth to a baby in the Ceske Budejovice Hospital from November 2008 to March 2009. The study was approved by the Local Institutional Review Board. All participants provided written informed consent and completed an extensive questionnaire on pregnancy history (medication, diseases), delivery course, newborn characteristics and life style (smoking, diet, alcohol drinking, area of residency). Only subjects who underwent vaginal delivery were included in the study. Based on smoking history, the women were divided into two groups, “smokers” (N=20) and “non-smokers” (N=52), while passive smokers (N=19) were excluded from the study. Smoking status was further confirmed by detection of excessive plasma levels of cotinine (the major nicotine metabolite) in maternal blood.