A Gelatin Hydrogel to Study Endometrial Angiogenesis and Trophoblast Invasion

ABSTRACT As the lining of the uterus and site of blastocyst implantation, the endometrium is a dynamic tissue that undergoes rapid cycles of growth, breakdown, and remodeling each menstrual cycle. Significant vascular remodeling is also driven by trophoblast cells that form the outer layer of the blastocyst. Trophoblast invasion and remodeling enhance blood flow to the embryo ahead of placentation. Insight into endometrial vascular remodeling and trophoblast invasion would provide key insights into endometrial physiology and cellular interactions critical for establishment of pregnancy. The objective for this study was to develop a tissue engineering platform to investigate processes of endometrial angiogenesis and trophoblast invasion in a 3D environment. We report adaptation of a methacrylamide-functionalized gelatin hydrogel that presents matrix stiffness in the range of the native tissue. Further, the hydrogel supports the formation of stable endometrial endothelial cell networks and attachment of a stratified endometrial epithelial cell layer, enables culture of a hormone-responsive stromal compartment, and provides the capacity to monitor the kinetics of trophoblast invasion. With these studies, we provide a series of techniques that will instruct researchers in the development of endometrial models of increasing complexity.