Histological villous maturation in placentas of complicated pregnancies
Philippe Vangrieken1, Sizzle F. Vanterpool2,7, Frederik J. van Schooten1, Salwan Al-Nasiry3, Peter Andriessen4, Ellen Degreef5, Joachim Alfer6, Boris W. Kramer3,7 and Ulrike von Rango8
1School of Nutrition and Translational Research in Metabolism (NUTRIM), Department of Pharmacology and Toxicology, Maastricht University Medical Center+, Maastricht, the Netherlands, 2Department of Reproductive Medicine, University Hospital Ghent, Ghent, Belgium, 3School for Oncology and Developmental Biology (GROW), Department of Obstetrics and Gynaecology, Maastricht University Medical Center+, Maastricht, 4Department of Pediatrics, Máxima Medical Center, Veldhoven, the Netherlands, 5Foundation Laboratory for Pathology and Medical Microbiology (PAMM), Eindhoven, The Netherlands, 6Department of Pathology, Kaufbeuren-Ravensburg, Ravensburg, Germany, 7School for Mental Health and Neurosciences (MHeNS), Department of Pediatrics and 8Department of Anatomy and Embryology, Maastricht University Medical Center+, the Netherlands
Offprint requests to: Philippe Vangrieken, School of Nutrition and Translation Research in Metabolism (NUTRIM), Department of Pharmacology, Maastrich Univeristy Medical Center+, Maastricht, the Netherlands. p.vangrieken@maastrichtuniversity.nl
Summary. Chorioamnionitis and preeclampsia account for the majority of preterm births worldwide. Thus far, adequate methods for early detection or prevention of these diseases are lacking. In preeclampsia, accelerated villous maturation is believed to compensate placental insufficiency. However, little is known about the effects of placental inflammation in chorioamnionitis on villous maturation. Therefore, we established a set of morphological parameters to evaluate histological villous maturity in pregnancies complicated by chorioamnionitis and preeclampsia. Preterm placentas complicated by chorioamnionitis or preeclampsia were compared to idiopathic preterm placentas and term controls. Histological villous maturation was analyzed by means of 17 histological markers. Fourteen of these markers provided information on absolute and relative numbers of the terminal villi (TV), the extent of their vascularization (using CD31-stained sections) and their exchange capacity. In addition, the numbers of syncytial bridges, syncytial apoptotic knots and shed syncytiotrophoblasts were counted. Accelerated villous maturation in preeclampsia was demonstrated by means of histological villous remodeling and confirmed by 11 relevant markers. Chorioamnionitis, however, only showed increased area of fetal capillaries. In preeclampsia, placentas may transition from growth to maturation earlier than placentas in normal pregnancies, whereas in chorioamnionitis placental changes are more acute and therefore less elaborated at a structural level. Regression analysis suggests the number of all villi and the number of terminal villi as a percentage of all villi as parameters to evaluate histological villous maturity in preeclamptic placentas and to assist diagnosis. However, we would recommend to analyze all 11 relevant parameters to judge placental maturity in detail. Histol Histopathol 35, 849-862 (2020)
Key words: Histological villous maturation, Chorioamnionitis, Preeclampsia, Preterm birth, Scoring method
DOI: 10.14670/HH-18-205