fibrin and Chorioamnionitis

Chronic inflammatory placental disorders are a group of rare but devastating gestational syndromes associated with adverse pregnancy outcome. This review focuses on three related conditions: villitis of unknown etiology (VUE), chronic histiocytic intervillositis (CHI) and massive perivillous fibrin deposition (MPFD). The hallmark of these disorders is infiltration of the placental architecture by maternal immune cells and disruption of the intervillous space, where gas exchange between the mother and fetus occurs. Currently, they can only be detected through histopathological examination of the placenta after a pregnancy has ended. All three are associated with a significant risk of recurrence in subsequent pregnancies. Villitis of unknown etiology is characterised by a destructive infiltrate of maternal CD8+ T lymphocytes invading into the chorionic villi, combined with activation of fetal villous macrophages. The diagnosis can only be made when an infectious aetiology has been excluded. VUE becomes more common as pregnancy progresses and is frequently seen with normal pregnancy outcome. However, severe early-onset villitis is usually associated with fetal growth restriction and recurrent pregnancy loss. Chronic histiocytic intervillositis is characterised by excessive accumulation of maternal CD68+ histiocytes in the intervillous space. It is associated with a wide spectrum of adverse pregnancy outcomes including high rates of first-trimester miscarriage, severe fetal growth restriction and late intrauterine fetal death. Intervillous histiocytes can also accumulate due to infection, including SARS-CoV-2, although this infection-induced intervillositis does not appear to recur. As with VUE, the diagnosis of CHI requires exclusion of an infectious cause. Women with recurrent CHI and their families are predisposed to autoimmune diseases, suggesting CHI may have an alloimmune pathology. This observation has driven attempts to prevent CHI with a wide range of maternal immunosuppression. Massive perivillous fibrin deposition is diagnosed when >25% of the intervillous space is occupied by fibrin, and is associated with fetal growth restriction and late intrauterine fetal death. Although not an inflammatory disorder per se, MPFD is frequently seen in association with both VUE and CHI. This review summarises current understanding of the prevalence, diagnostic features, clinical consequences, immune pathology and potential prophylaxis against recurrence in these

Topics: Abortion, Habitual; Chorioamnionitis; Chronic Disease; COVID-19; Female; Fetal Death; Fetal Growth Retardation; Fibrin; Humans; Placenta; Pregnancy; Pregnancy Outcome; SARS-CoV-2; Syndrome

Stillbirth is a recognized complication of COVID-19 in pregnant women that has recently been demonstrated to be caused by SARS-CoV-2 infection of the placenta. Multiple global studies have found that the placental pathology present in cases of stillbirth consists of a combination of concurrent destructive findings that include increased fibrin deposition that typically reaches the level of massive perivillous fibrin deposition, chronic histiocytic intervillositis, and trophoblast necrosis. These 3 pathologic lesions, collectively termed SARS-CoV-2 placentitis, can cause severe and diffuse placental parenchymal destruction that can affect >75% of the placenta, effectively rendering it incapable of performing its function of oxygenating the fetus and leading to stillbirth and neonatal death via malperfusion and placental insufficiency. Placental infection and destruction can occur in the absence of demonstrable fetal infection. Development of SARS-CoV-2 placentitis is a complex process that may have both an infectious and immunologic basis. An important observation is that in all reported cases of SARS-CoV-2 placentitis causing stillbirth and neonatal death, the mothers were unvaccinated. SARS-CoV-2 placentitis is likely the result of an episode of SARS-CoV-2 viremia at some time during the pregnancy. This article discusses clinical and pathologic aspects of the relationship between maternal COVID-19 vaccination, SARS-CoV-2 placentitis, and perinatal death.

Topics: Chorioamnionitis; COVID-19; COVID-19 Vaccines; Female; Fibrin; Humans; Infant, Newborn; Infectious Disease Transmission, Vertical; Mothers; Perinatal Death; Placenta; Pregnancy; Pregnancy Complications, Infectious; SARS-CoV-2; Stillbirth

The aim of the research was to set the optical density quantitative parameters of the von Willebrand factor immunohistochemical staining (vWF) in the endothelium and fibrinoid of the placenta during the secundines inflammation concomitant with iron deficiency anemia in gravidas. The total number of 198 placentas was studied. The immunohistochemical technique was performed using the visualization of the primary antibodies to vWF with a diaminobenzidine dye polymer system. The optical density of the histochemical staining was measured by means of computer microdensitometry after the digital copies of the images had been obtained. All the cases of the secundines inflammation and the structures under study were found to have a significant increase in the optical density of the vWF immunohistochemical staining in the endothelium of the blood vessels as compared to the physiological pregnancy. Iron deficiency anemia in gravidas (IDAG) contributes to an increase in the indices of the inflammation, the highest data pertaining to the endothelial cells of the placental basal plate in chronic basal deciduitis. The optical density of the staining in the fibrinoid of the chorionic and basal plates during chronic forms of chorioamnionitis and basal deciduitis is higher than the optical density inherent in physiological pregnancy. The intensity of staining increases in presence of all the forms of inflammation on the background of IDAG in comparison with physiological pregnancy with placenta inflammation. Compared with IDAG in absence of the inflammatory processes, only chronic inflammatory processes reveal a change in indices. Consequently, the optical density of the staining significantly increases in the endothelium of blood vessels in all forms of the secundines inflammation, in comparison with the physiological pregnancy, whereas in fibrinoid the same process is reported only in chronic course. In this case, IDAG is accompanied by maximum levels of optical density in the endothelium and fibrinoid, whereas in chronic, the average indices are higher than those in acute forms.

Topics: Anemia, Iron-Deficiency; Chorioamnionitis; Endothelium, Vascular; Female; Fibrin; Humans; Image Processing, Computer-Assisted; Inflammation; Placenta; Pregnancy; Pregnancy Complications, Hematologic; von Willebrand Factor