engleski

Assessment of steroid disruption and metal concentrations in human placenta: effects of cigarette smoking

Cigarette smoke contains, beside several thousands of toxic chemicals, ca. 30 metal ions, including Cd, As, Pb, Ni, Cr, Al, Sb, Cu, Fe, and radioactive elements. Many metals are highly reactive and contribute to the production of oxidative stress, which is a starting point of toxic and carcinogenic effects of tobacco smoke. In the general population, cigarette smoke is the chief environmental source of Cd, a highly toxic agent and confirmed human carcinogen. By affecting woman’ s health and the internal environment of her descendant/s, toxic metals may cause immediate and/or delayed effects on virtually all organ systems. Women of childbearing age and growing infants are prone to deficiencies of essential elements (Fe, Zn, Cu, Ca etc.) and thus are especially sensitive to toxic-essential element interactions. During pregnancy, toxic metals can compromise fetal health directly in utero, by passing the placental barrier, and indirectly, by accumulation in the placenta and interfering with nutrient transfer to the fetus. Toxic metals can disrupt principal placental functions in maintenance of pregnancy and fetal viability, by affecting the production of placental hormones. Their accumulation in the placenta may compromise prevention of placental-fetal rejection by maternal immune system and fetal response to antigen exposure in utero. Only a few studies so far have validated placental steroid disruption due to metal exposure. Cadmium ions accumulate in human placental (trophoblast) cells where they suppress progesterone release without apparent inhibition of syncytial development. Increase in placental Cd may be commensurate with a decrease in placental progesterone concentrations in women exposed to cigarette smoke during pregnancy. Animal studies support the findings of Cd-induced ovarian and placental steroid disruption during pregnancy. A concomitant low-Fe diet has an additive effect on Cd-induced placental steroid disruption. Human placenta can be used as a 'dual purpose specimen' for monitoring harmful substances in both external maternal and internal fetal environment ; the latter being the maternal organism itself.

cadmium, metal ions, placenta, steroid disruption, tobacco smoking, risk for infant health

Chapter has originally been published by invitation (in 2007) and its research summary selected for reprinting in a new thematic edition by the same publisher (in 2015). / Poglavlje je prema odabiru izdavača za kojega je izvorno u cijelosti napisano na poziv (2007.) ponovno objavljeno - njegov sažetak istraživanja u novom tematskom izdanju istog izdavača (2015.)