Inadequate maternal vascular response to placentation in pregnancies complicated by pre-eclampsia and by small-for-gestational age infants.

Endometriosis

Many mammalian viruses have acquired genes from their hosts during their evolution1. The rationale for these acquisitions is usually quite clear: the captured genes are subverted to provide a selective advantage to the virus. Here we describe the opposite situation, where a viral gene has been sequestered to serve an important function in the physiology of a mammalian host. This gene, encoding a protein that we have called syncytin, is the envelope gene of a recently identified human endogenous defective retrovirus, HERV-W2. We find that the major sites of syncytin expression are placental syncytiotrophoblasts, multinucleated cells that originate from fetal trophoblasts. We show that expression of recombinant syncytin in a wide variety of cell types induces the formation of giant syncytia, and that fusion of a human trophoblastic cell line expressing endogenous syncytin can be inhibited by an anti-syncytin antiserum. Our data indicate that syncytin may mediate placental cytotrophoblast fusion in vivo, and thus may be important in human placental morphogenesis.

Syncytin is a captive retroviral envelope protein involved in human placental morphogenesis.

Preterm birth is associated with 5 to 18% of pregnancies and is a leading cause of infant morbidity and mortality. Spontaneous preterm labor, a syndrome caused by multiple pathologic processes, leads to 70% of preterm births. The prevention and the treatment of preterm labor have been long-standing challenges. We summarize the current understanding of the mechanisms of disease implicated in this condition and review advances relevant to intra-amniotic infection, decidual senescence, and breakdown of maternal-fetal tolerance. The success of progestogen treatment to prevent preterm birth in a subset of patients at risk is a cause for optimism. Solving the mystery of preterm labor, which compromises the health of future generations, is a formidable scientific challenge worthy of investment.

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Preterm labor: One syndrome, many causes

In a healthy body, ROS (reactive oxygen species) and antioxidants remain in balance When the balance is disrupted towards an overabundance of ROS, oxidative stress (OS) occurs OS influences the entire reproductive lifespan of a woman and even thereafter (ie menopause) OS results from an imbalance between prooxidants (free radical species) and the body's scavenging ability (antioxidants) ROS are a double-edged sword – they serve as key signal molecules in physiological processes but also have a role in pathological processes involving the female reproductive tract ROS affect multiple physiological processes from oocyte maturation to fertilization, embryo development and pregnancy It has been suggested that OS modulates the age-related decline in fertility It plays a role during pregnancy and normal parturition and in initiation of preterm labor Most ovarian cancers appear in the surface epithelium, and repetitive ovulation has been thought to be a causative factor Ovulation-induced oxidative base damage and damage to DNA of the ovarian epithelium can be prevented by antioxidants There is growing literature on the effects of OS in female reproduction with involvement in the pathophsiology of preeclampsia, hydatidiform mole, free radical-induced birth defects and other situations such as abortions Numerous studies have shown that OS plays a role in the pathoysiology of infertility and assisted fertility There is some evidence of its role in endometriosis, tubal and peritoneal factor infertility and unexplained infertility This article reviews the role OS plays in normal cycling ovaries, follicular development and cyclical endometrial changes It also discusses OS-related female infertility and how it influences the outcomes of assisted reproductive techniques The review comprehensively explores the literature for evidence of the role of oxidative stress in conditions such as abortions, preeclampsia, hydatidiform mole, fetal embryopathies, preterm labour and preeclampsia and gestational diabetes The review also addresses the growing literature on the role of nitric oxide species in female reproduction The involvement of nitric oxide species in regulation of endometrial and ovarian function, etiopathogenesis of endometriosis, and maintenance of uterine quiescence, initiation of labour and ripening of cervix at parturition is discussed Complex interplay between cytokines and oxidative stress in the etiology of female reproductive disorders is discussed Oxidant status of the cell modulates angiogenesis, which is critical for follicular growth, corpus luteum formation endometrial differentiation and embryonic growth is also highlighted in the review Strategies to overcome oxidative stress and enhance fertility, both natural and assisted are delineated Early interventions being investigated for prevention of preeclampsia are enumerated Trials investigating combination intervention strategy of vitamin E and vitamin C supplementation in preventing preeclampsia are highlighted Antioxidants are powerful and there are few trials investigating antioxidant supplementation in female reproduction However, before clinicians recommend antioxidants, randomized controlled trials with sufficient power are necessary to prove the efficacy of antioxidant supplementation in disorders of female reproduction Serial measurement of oxidative stress biomarkers in longitudinal studies may help delineate the etiology of some of the diosorders in female reproduction such as preeclampsia

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Robert Pijnenborg

Papers

The "Great Obstetrical Syndromes" are associated with disorders of deep placentation.

The Uterine Spiral Arteries In Human Pregnancy: Facts and Controversies

A study of placental bed spiral arteries and trophoblast invasion in normal and severe pre-eclamptic pregnancies

Trophoblastic invasion of human decidua from 8 to 18 weeks of pregnancy.

Uteroplacental arterial changes related to interstitial trophoblast migration in early human pregnancy