A 3D Bio-Printed Hormone-Responsive Model for Embryo Implantation

Despite the immense progress in assisted reproductive technologies, success rates stand at approximately 30% per embryo transfer. There is a great need for a proper model that will simulate implantation and allow for the examination of treatment options. We aim to develop a 3D culture system consisting of both epithelial and stromal endometrial cells encapsulated in an alginate-based hydrogel, cultured under a specific hormone regime. Using a spheroid as an embryo surrogate, we strive to examine implantation. Such a hormone-responsive model will allow for different manipulations to improve implantation success rates.

RL95-2 was used as epithelium, THESCs as stroma, and 150-200µm JAR spheroids as embryo surrogates. Cells were embedded within alginate and printed either alone or as a bi-layered structure. Cell viability in constructs was confirmed for over a week. Jar spheroids were placed upon the bi-layered construct and incubated for 48h. Jar spheroids successfully infiltrated through the epithelial layer to the stromal layer, suggesting their invasiveness.

To simulate hormonal regulation, cells were primed with estrogen (2 d), followed by a combination of estrogen and progesterone (3 d). Protein expression levels of E-cadherin and Estrogen Receptor α (ERα) were evaluated by Western Blot. E-cadherin expression was significantly higher, and ERα was slightly lower in the hormone-treated constructs, compared to the untreated controls.

This study will enable researchers to investigate and develop a proper treatment to improve embryo implantation and In Vitro Fertilization success rates.