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In Vitro Human Placental Studies to Support Adenovirus-Mediated VEGF-D

Michelle Desforges, Alexandra Rogue, Nick Pearson, Carlo Rossi, Elena Olearo, Roy Forster, Mark Lees, Neil J Sebire, Susan L Greenwood, Colin P Sibley, Anna L David, Paul Brownbill

Hum Gene Ther Clin Dev. 2018 Mar;29(1):10-23.

PMID: 29228803

Abstract:

Severe fetal growth restriction (FGR) affects 1 in 500 pregnancies, is untreatable, and causes serious neonatal morbidity and death. Reduced uterine blood flow (UBF) is one cause. Transduction of uterine arteries in normal and FGR animal models using an adenovirus (Ad) encoding VEGF isoforms increases UBF and improves fetal growth in utero. Understanding potential adverse consequences of this therapy before first-in-woman clinical application is essential. The aims of this study were to determine whether Ad.VEGF-DΔNΔC (1) transfers across the human placental barrier and (2) affects human placental morphology, permeability and primary indicators of placental function, and trophoblast integrity. Villous explants from normal term human placentas were treated with Ad.VEGF-DΔNΔC (5 × 107-10 virus particles [vp]/mL), or virus formulation buffer (FB). Villous structural integrity (hematoxylin and eosin staining) and tissue accessibility (LacZ immunostaining) were determined. Markers of endocrine function (human chorionic gonadotropin [hCG] secretion) and cell death (lactate dehydrogenase [LDH] release) were assayed. Lobules from normal and FGR pregnancies underwent ex vivo dual perfusion with exposure to 5 × 1010 vp/mL Ad.VEGF-DΔNΔC or FB. Perfusion resistance, para-cellular permeability, hCG, alkaline phosphatase, and LDH release were measured. Ad.VEGF-DΔNΔC transfer across the placental barrier was assessed by quantitative polymerase chain reaction in DNA extracted from fetal-side venous perfusate, and by immunohistochemistry in fixed tissue. Villous explant structural integrity and hCG secretion was maintained at all Ad.VEGF-DΔNΔC doses. Ad.VEGF-DΔNΔC perfusion revealed no effect on placental permeability, fetoplacental vascular resistance, hCG secretion, or alkaline phosphatase release, but there was a minor elevation in maternal-side LDH release. Viral vector tissue access in both explant and perfused models was minimal, and the vector was rarely detected in the fetal venous perfusate and at low titer. Ad.VEGF-DΔNΔC did not markedly affect human placental integrity and function in vitro. There was limited tissue access and transfer of vector across the placental barrier. Except for a minor elevation in LDH release, these test data did not reveal any toxic effects of Ad.VEGF-DΔNΔC on the human placenta.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
IAR42413771 VEGF-D human VEGF-D human Price
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