Multi-organ dysfunction and outcomes in pregnancy associated COVID-19 infection - descriptive review of pathological findings.

OBJECTIVE(S): Comparative clinical and morphological characterization of lesions of the vascular and nervous system in cases of maternal death associated with COVID-19. STUDY DESIGN: The study included autopsy in 12 cases of maternal death with a positive intravital result for SARS-CoV-2 by reverse transcription polymerase chain reaction. For histopathology, tissue samples were taken from the internal organs of each patient. Pieces of organs were fixed and stained according to the standard protocol. The relative number of microvessels with vasculitis and fibers of the peripheral nervous system with infiltration by immune cells was studied. All morphological changes were classified depending on the severity of the damage. RESULTS: The average age of patients with a fatal outcome was 35 ± 4.4 years. Time to death after onset of symptoms averaged 16 ± 4.4 days. Dystrophic lesions (necrosis and apoptosis) of the villous and extravillous trophoblast and decidual tissue were observed in the studied placentas. Histopathological signs of mild and severe lesions of the peripheral nervous system in the organs of the gastrointestinal tract were detected in 2 (16.7%) and 10 (83.3%) cases, respectively, in the myocardium in 4 (33.3%) and 8 (66.7%) cases. Histopathological signs of severe damage to the microvascular bed in the organs of the gastrointestinal tract were registered in 9 (75%) cases. CONCLUSION(S): The main clinical feature of this cohort was that death occurred in a long-term period, in most cases with a negative PCR. The histopathological pattern was a non-acute injury with an immune component of the microvascular bed and the autonomic nervous system with predominant damage to the myocardium and intestines. WHAT DOES THIS STUDY ADD TO THE CLINICAL WORK: This study makes it possible to even better study the immunopathological profile in organs and tissues in pregnant women with a fatal outcome when affected by a viral infection, in particular Covid-19. This knowledge can be used when humanity encounters other viral pandemics in the future.

Immaturity for gestational age of microvasculature and placental barrier in term placentas with high weight.

OBJECTIVE: Villous immaturity for gestational age is a multifactorial developmental deviation associated with unexpected placental insufficiency, fetal hypoxia and term fetal death. In our previous work we have shown that immature CD15+/CD31+/CD34+ endothelial cells were an important indicator of placental villous immaturity and chronic insufficiency. The aim of this study was to perform a comparative analysis of CD15-marked immaturity in the vessel walls between normal and pathological term placentas of clinically and structurally heterogenous groups with normal, low and high weight. STUDY DESIGN: 165 clinically normal and pathological placentas of gestational age 39-42 with normal weight (25-75 percentile), low weight (<10 percentile) and high weight (>90 percentile) were structurally and immunohistochemically analyzed. Excluded were placentas with a severe form of placental insufficiency associated with intrauterine fetal death, low APGAR-score, genetic and chromosomal diseases or placental inflammations. The distribution patterns of CD15, CD31 and CD34 were assessed separately in the macrovasculature, microvasculature and placental barrier (PB) - associated capillaries. RESULTS: All placental groups with normal weight, low weight and high weight include normal, accelerated villous maturation or villous immaturity independent of their weight. However, a significant increase of immature CD15+/CD31+/CD34+ endothelial cells was detected in microvasculature and PB -associated capillaries in high weight-placentas (63.5%/52.2%), compared to those of normal weight (13.8%/8.2%) and low weight (16.1%/17.8%). The distribution of macrovascular immature CD15+/CD31+/CD34+ endothelial cells did not show such marked differences. CONCLUSION: We have identified the immaturity of microvasculature and PB -associated capillaries with a pathological persistency of immature CD15+/CD31+/CD34+ endothelial cells and a reduction of terminally differentiated CD15-/CD31+/CD34+ endothelial cells in a structurally and clinically heterogeneous group of high weight-placentas. We assume that immaturity of placental vessels are part of prenatal adaptational processes that can be recruited in different emergency situations and may provide potential targets of therapeutic correction of placental growth and chronic insufficiency. We therefore recommend the use of CD15-based immunophenotyping as a method to identify latent unfavorable conditions of fetal development in the intrauterine life and individual risk of disease in the postnatal period.

CD15 - a new marker of pathological villous immaturity of the term placenta.

INTRODUCTION: Idiopathic immaturity is one of the main reasons for latent placental insufficiency and antenatal hypoxia. Postnatal identification of the immature placental phenotype may help early stratification of a heterogeneous population of newborns and individually identify risk of disease in the immediate postnatal life. The aim of the study was to determine the relevant diagnostic markers associated with pathological placental immaturity. METHODS: 111 tissue samples from normal and pathological term placentas with persisting villous immaturity comprised the comparative immunohistochemical study (CD15, CD34). Positive immunohistochemical reactions were quantitatively assessed in the chorionic plate and vessels of the villi of different histological type. RESULTS: We have shown that pathological villous immaturity is attended by significantly increased CD15-expression in the macro- and microvascular endothelium compared with the normal placenta. CD34-expression was not different from that in normal placentas. DISCUSSION: This paper documents the correlation of CD15+ endothelium in the macrovascular fetoplacental vessels with a severe form of villous immaturity associated with fetal hypoxia/asphyxia and erythroblastosis. Increased CD15-expression only in the microvascular segment of the fetoplacental vessels correlated with moderate villous immaturity and was associated with GDM, idiopathic fetal macrosomia and nonspecific chronic villitis. CONCLUSION: We propose that "immature" CD15+ endothelium is an important diagnostic marker of persisting villous immaturity and chronic placental dysfunction. The level of CD15 expression in the macro- and microvasculature reflects the degree of pathological placental villous immaturity.