387: The expression of heparanase in term and preterm human placentas

Abstract

Heparanase is an endo-β-glucuronidase that cleaves side chains of heparan-sulfate proteoglycans, an integral constituent of the extra cellular matrix. The abundance of heparanase in placental trophoblast cells implies its role in the processes of placentation and trophoblast invasion. This study aims to explore the involvement of heparanase in parturition and preterm deliveries (PTD). Sixteen human placentas were collected following singleton spontaneous onset term vaginal deliveries (n=6), spontaneous onset preterm vaginal deliveries (n=7) and term elective cesarean sections (n=3). Placentas were excluded if any maternal chronic illness, pregnancy or delivery complications (hypertensive disorder, suspected amnionitis, placental abruption etc.). Placental tissue samples were dissected, homogenized and proteins were extracted. Additionally, cryosections were prepared from the placental tissues. Heparanase expression was evaluated utilizing western blot analysis and immunofluorescence staining using heparanse specific antibodies. Heparanase expression was compared between the study groups qualitatively and quantitatively by student t-test. P-value < 0.05 was considered significant. Western blot analysis results demonstrate increased expression of both pro-heparanase and heparanase in PTD placentas compared to term vaginal (TV) placentas (Figure 1). Accordingly, immunofluorescence staining shows elevated heparanase expression in PTD placentas compared to term vaginal placentas (5.1±0.92 vs. 1.2±0.18, p< 0.005). Contrarily, the expression level of heparanase was not altered in term cesarean section (TCS) placentas as compared to term vaginal deliveries placentas (1.8±0.39 vs. 1.2±0.18, p=0.06) (Figure 2). This study demonstrates for the first time that preterm vaginal deliveries are associated with over-expression of heparanase in placental tissue. This may imply a direct effect of heparanase on preterm labor. Further studies should evaluate the functional role by which heparanase influence preterm delivery.View Large Image Figure ViewerDownload Hi-res image Download (PPT)