Pregnancy is a unique physiological process that involves intricate interplay of inflammatory and anti-inflammatory milieu, hormonal changes, and cellular and molecular events at the maternal-fetal interface (1). Pre-eclampsia (PE) is a pregnancy-specific disorder (2) characterized by new onset of maternal hypertension and proteinuria after 20 weeks of gestation in a previously normotensive woman (3). PE is a multisystem disorder involves altered homeostasis of oxidants-antioxidants, inflammatory process and endothelial dysfunction (4).
During the physiological process of oxidation of organic materials by molecular oxygen to produce energy, a number of reactive oxygen species (ROS) are formed (5). Normally, ROS are neutralized by a broad spectrum of naturally occurring protective antioxidants, such as superoxide dismutase (SOD), so as to prevent oxidative stress (OS) (6) that implies an imbalance between ROS production and cellular and tissue antioxidant defense system (7). OS leads to damage all cellular components and modifies their physiological functions (8).
Oxidative stress is a common feature of normal pregnancy, but persistent, overwhelming OS leads to consumption and decline of antioxidants, affecting placental antioxidant capacity with subsequent damage of placental tissue components (9); thus inducing a form of accelerated placental ageing (10). In addition, ROS could stimulate platelet adhesion and aggregation leading to intravascular coagulopathy with subsequent placental infarction and impairment of the uteroplacental blood flow (11). OS also plays an important immuno-regulatory role during pregnancy (12). Moreover, the balance between the protective and destructive mechanisms of placental autophagy and apoptosis are often influenced by OS, and the proper interactions between them play an important role in placental homeostasis (13). OS, immune disturbances and OS-induced imbalance between autophagy and apoptosis seem to be linked with adverse pregnancy outcomes such as spontaneous abortion, PE and intrauterine growth restriction (6).
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