Peculiar Fibronectin immunohistochemical staining in placental tissue of pathological pregnancies associated with insufficient placentation

Abstract

Objective: To investigate the role of Fibronectin, an extracellular matrix protein essential in the process of trophoblastic invasion, in the development of pregnancy-related pathologies associated with insufficient placentation. Materials and methods: Retrospective study including 36 early (< 34th gestational age) preeclampsia (PE), 14 late (≥34th gestational age) PE, 6 HELLP syndrome (hemolysis, elevated liver enzymes, low platelet count), 18 small for gestational age (SGA) fetuses (under the 10th percentile), 17 early intrauterine growth restriction (IUGR), 35 late IUGR, and 64 controls. Fibronectin localization was evaluated in placental tissue microarray by immunohistochemistry and the amount assessed by intensity semi-quantitative score (3 = strong, 2 = moderate, and 1 = weak). Results: Fibronectin was present in cytoplasm and peri-cytoplasm areas. Moreover, in general Fibronectin cytoplasm staining had a higher intensity score among cases compared to controls. Furthermore, both cytoplasm and peri-cytoplasm Fibronectin intensity was higher in early PE (1, IQR 0 – 1), HELLP (1, IQR 1 – 1), and early IUGR (1, IQR 1 – 1) than in controls of 22 – 34 weeks' gestation (0, IQR 0 – 1) (p < 0.05). Intensity was also greater in late PE (1, IQR 0 – 1) than late IUGR (0, IQR 0 – 0) and controls (0, IQR 0 – 1) of 34 – 42 weeks' gestation, as well as in late PE associated with IUGR (1, IQR 0 – 1) than in IUGR alone (0, IQR 0 – 0) and in early IUGR (1, IQR 1 – 1) than late IUGR (0, IQR 0 – 0) (p < 0.05). In addition, peri-cytoplasmic Fibronectin was found to be significantly more represented in late PE associated with IUGR (2, IQR 1 – 2) than in controls (1, IQR 0 – 1) (p < 0.05). Conclusions: Fibronectin shows higher staining among PE, HELLP and IUGR cases compared to controls, probably reflecting a common underlying pathological mechanism coupled with insufficient placentation. Late IUGR seems to be unaffected by Fibronectin amount, suggesting a peculiar pathogenetic pattern.