Regulation of Placentation by Environmental Factors

Abstract

Changes in the maternal environment can impair fetal growth and development, which may result in increased susceptibility to diseases in postnatal life. The placental nutrient sensing capacity may integrate these perturbations with information from intrinsic nutrient sensing signaling pathways to regulate secretion of hormones and placental nutrients and oxygen transfer. Placental responses to perturbations in the maternal compartment are complex and poorly understood, highlighting an urgent need for further well-designed and mechanistic research in this area. Intervention strategies to alleviate pregnancy complications and prevent fetal programing of adult disease are likely to be the most effective if placental function is targeted. The effect of environment exposure pollutants on placentation is warranted since pregnant mothers are often exposed to these factors during preconception to gestational period. Impaired placentation that ultimately influences fetus outcome is the center of many development disorders and contributes as an independent risk factor for the adult chronic diseases. The interaction of genes and the environment that predict the fetus outcome was evidenced where birth weight was reduced in babies derived from the women smoked during pregnancy irrespective of their genotypes. While susceptible genotypes in addition to smoking contributed further reduction in the birth weight explained why we need to measure the quantum of changes in genotypes that comes from the lifestyle habit, i.e., smoking or alcohol, etc. during pregnancy (please see Chap. 8). Placental gene expression affects its invasive and functional capacities and thereby the growth of the feto-placental unit. Placental secreted factors that influence the maternal adaptation to pregnancy and, hence, the health of both mother and baby are influenced by the stress factors. Many studies raised the issue that prenatal exposure to environmental pollutants that include air pollutants, food contaminants, and chemicals present in consumer products may contribute additional insult to the early developmental in utero. The biomarker measurements of such conditions by mimicking their effect on placental growth and development and gene expression may provide a new insight into the association between early exposure of these modifiable environmental factors and fetus outcome. This chapter will review the subtle effect induced by environmental risk factors exposed to mother during pregnancy which can lead to functional insufficiency in the placenta due to alteration in the gene expression of the functional pathways associated with placentation. Impact of environmental toxins on placental blood flow, vasculature, and angiogenesis of the placenta are also discussed.