Defense and infection of the human placenta

Abstract

The placenta functions as a shield against infection of the fetus. The innate and adaptive immune defenses of the developing fetus are poorly equipped to fight infections. Infection by bacteria, viruses, and protozoa may cause infertility, spontaneous abortion, stillbirth, growth retardation, anomalies of development, premature delivery, neonatal morbidity, and mortality. However, appreciation of the human microbiome and host cell-microbe interactions must be taken into consideration as we try to determine what interactions are pathologic. Infection is typically recognized histologically by the presence of inflammation. Yet, several factors make comparison of the placenta to other human organs difficult. The placenta comprises tissues from two persons, complicating the role of the immune system. The placenta is a temporary organ. It must be eventually expelled; the processes leading to partuition involve maternal inflammation. What is normal or pathologic may be a function of timing or extent of the process. We now must consider whether bacteria, and even some viruses, are useful commensals or pathogens. Still, recognizing infection of the placenta is one of the most important contributions placental pathologic examination can give to care of the mother and neonate. This review provides a brief overview of placental defense against infection, consideration of the placental microbiome, routes of infection, and the histopathology of amniotic fluid infection and TORCH infections.

Changes in the Vα7.2+ CD161++ MAIT cell compartment in early pregnancy are associated with preterm birth in HIV‐positive women

“…MAIT cells from the female genital tract appear to be phenotypically different, with a highly cytotoxic phenotype, 54 producing more IL‐17 and IL‐22 and less IFN‐γ and TNF‐α than circulating MAIT cells 55 . Considering intrauterine infection has been implicated in a large proportion of PTB cases, 1 and that maternal immune cells are recruited from intervillous blood in intrauterine infection, 56 deranged placental MAIT cell immunology may be significantly contributing to an increased risk of PTB in HIV+ women. Further exploration of the relationship between circulating MAIT cells and MAIT cells at the maternal‐foetal interface in HIV+ women is warranted.…”

Immune and Apoptosis Mechanisms Regulating Placental Development and Vascularization in Preeclampsia

“…During the implantation of the embryo, a new transient organ is formed connecting mother and fetus, the placenta (Burton and Fowden, 2015). The structure of the placenta will, during pregnancy, provide a range of functions such as fetal nutrition and oxygenation, as well as the secretion of endocrine factors, also building a maternal-fetal immune tolerance (Heerema-McKenney, 2018).…”

A human Amniotic Membrane plug to manage high myopic macular hole associated with retinal detachment

“…). Furthermore, amniotic membrane is a rich source of biologically active factors and therefore promotes healing and acts as an effective material for wound dressing (Heerema‐McKenney ; Kaur & Bathla ; Murri et al. ; Sane et al.…”

“…Amniotic membrane supports epithelialization and has anti-fibrotic, antiinflammatory, anti-angiogenic and anti-microbial features (Tseng 2001;Tseng et al 2004;Waked & El-Kazzi 2005;Tehrani et al 2013;Niknejad et al 2015Niknejad et al , 2016Cheng et al 2016;Deihim et al 2016). Furthermore, amniotic membrane is a rich source of biologically active factors and therefore promotes healing and acts as an effective material for wound dressing (Heerema-McKenney 2018;Kaur & Bathla 2018;Murri et al 2018;Sane et al 2018;Olaya et al 2019;Otani et al 2019). In ophthalmology, amniotic membrane is increasingly used for ocular surface reconstruction, including the treatment of persistent epithelial defects and nonhealing corneal ulcers, corneal perforations and descemetoceles, bullous keratopathy, corneal disorders with associated limbal stem cell deficiency, pterygium, conjunctival reconstruction, corneoscleral melts and perforations, and glaucoma surgery.…”