The expression of heparanase in term and preterm human placentas

Abstract

Purpose

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).

Methods

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 in case of any maternal chronic illness, pregnancy or delivery complications apart from PTD. 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 heparanase specific antibodies. Heparanase expression was compared between the study groups qualitatively and quantitatively.

Results

Western blot analysis results demonstrated higher expression of both pro-heparanase and heparanase in PTD placentas compared to term vaginal placentas. 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 < .005). Expression level of heparanase was higher in term cesarean section placentas as compared to term vaginal deliveries placentas, but did not reach statistical significance (1.8 ± 0.39 vs. 1.2 ± 0.18, p = .06).

Conclusion

This study demonstrates for the first time that preterm vaginal deliveries are associated with higher 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.

Keywords:

• Heparanase
• placenta
• preterm delivery
• abnormal placentation
• parturition

Acknowledgements

We would like to thank doctor Neta Ilan and his staff at the Cancer and Vascular Biology Research Center in the Technion for their help on this work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Paper presentation information

The abstract was selected for a poster presentation at the SMFM 40th Annual Pregnancy Meeting, 4–6 February 2020, Grapevine, Texas, USA.

Additional information

Funding

This study was supported in part by the 2018 grant of the Israel Society of Obstetrics and Gynecology, northern branch, for OB/GYN residents. The sponsor had no part in the study design, collection, analysis or interpretation of data and had no part in writing the manuscript.