engleski

Assessment of Steroid Disruption and Metal Concentrations in Human Placenta: Effects of Cigarette Smoking

Numerous harmful substances from tobacco smoke can pass the placental barrier or accumulate in placental structures. Cigarette smoke contains several thousands of chemicals and approximately 30 metal ions, including cadmium, arsenic, lead, nickel, chromium, aluminum, antimony, copper, iron, and radioactive elements. Many metals are highly reactive and contribute to the production of oxidative stress, a starting point of toxic and carcinogenic effects of tobacco smoke. In the general population, cigarette smoke is the chief environmental source of cadmium, a confirmed human carcinogen. By affecting woman’ s health and the internal environment of her descendant(s), toxic metals may cause immediate and delayed ill effects on virtually all organ systems. Women of childbearing age and growing infants are prone to deficiencies of essential elements (iron, zinc, copper, calcium) and thus are especially sensitive to toxic-essential metal 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 inhibition of nutrient transfer to the fetus. Toxic metals can interfere with principal placental functions, 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 the concept of 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 cadmium is commensurate with a decrease in placental progesterone concentrations in women exposed to cigarette smoke during pregnancy. Animal studies support the findings of cadmium-induced ovarian and placental steroid disruption during pregnancy. A concomitant low iron diet has an additive effect on cadmium-induced placental steroid disruption. Human placenta can be used as a 'dual purpose specimen' for monitoring harmful substances in both the maternal and internal fetal environment when epidemiological variables for evaluation of exposure conditions are considered.

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

Chapter has been originally published by invitation (in 2007) and selected for reprinting in another thematic edition by the same publisher./ Poglavlje je prema odabiru izdavača za kojega je napisano na poziv (2007.) ponovno objavljeno u tematskom izdanju istog izdavača s drugim urednikom i naslovom izdanja (2011.)