Clustered integrin α5β1 ligand displays model fibronectin-mediated adhesion of human endometrial stromal cells

3D Bioprinting a human iPSC-derived MSC-loaded scaffold for repair of the uterine endometrium

Common events in the clinic, such as uterine curettage or inflammation, may lead to irreversible endometrial damage, often resulting in infertility in women of childbearing age. Currently, tissue engineering has the potential to achieve tissue manipulation, regeneration, and growth, but personalization and precision remain challenges. The application of "3D cell printing" is more in line with the clinical requirements of tissue repair. In this study, a porous grid-type human induced pluripotent stem cell-derived mesenchymal stem cell (hiMSC)-loaded hydrogel scaffold was constructed using a 3D bioprinting device. The 3D-printed hydrogel scaffold provided a permissive in vitro living environment for hiMSCs and significantly increased the survival duration of transplanted hiMSCs when compared with hiMSCs administered locally in vivo. Using an endometrial injury model, we found that hiMSC transplantation can cause early host immune responses (the serological immune response continued for more than 1 month, and the local immune response continued for approximately 1 week). Compared with the sham group, although the regenerative endometrium failed to show full restoration of the normal structure and function of the lining, implantation of the 3D-printed hiMSC-loaded scaffold not only promoted the recovery of the endometrial histomorphology (endometrial tissue and gland regeneration) and the regeneration of endometrial cells (stromal cells and epithelial cells) and endothelial cells but also improved endometrial receptivity functional indicators, namely, pinopode formation and leukemia inhibitory factor and αvβ3 expression, which partly restored the embryo implantation and pregnancy maintenance functions of the injured endometrium. These indicators were significantly better in the 3D-printed hiMSC-loaded scaffold group than in the unrepaired (empty) group, the hiMSCs alone group and the 3D scaffold group, and the empty group showed the worst repair results. Our study confirm that the 3D-printed hiMSC-loaded hydrogel scaffold may be a promising material for endometrial repair.

Three-dimensional perfused cell culture

Compelling evidence suggests the limitation and shortcomings of the current and well established cell culture method using multi-well plates, flasks and Petri dishes. These are particularly important when cell functions are sensitive to the local microenvironment, cell-cell and cell-extracellular matrix interactions. There is a clear need for advanced cell culture systems which mimic in vivo and more physiological conditions. This review summarises and analyses recent progress in three dimensional (3D) cell culture with perfusion as the next generation cell culture tools, while excluding engineered tissue culture where three dimensional scaffold has to be used for structural support and perfusion for overcoming mass transfer control. Apart from research activities in academic community, product development in industry is also included in this review.

Perfusion culture enhanced human endometrial stromal cell growth in alginate-multivalent integrin α5β1 ligand scaffolds

A method to functionalize alginate by introducing monomeric or self-assembling (tetrameric) fibronectin (FN) domains is described, leading to a functional scaffold, which is used for three dimensional (3D) culture of human endometrial stromal cells (EnSCs). EnSCs encapsulated in the functional alginate were cultured under perfusion using the TissueFlex® platform, a multiple parallel microbioreactor system for 3D cell culture. The effect of the novel scaffold and the effect of perfusion were examined. Cell viability, proliferation, and extracellular matrix (ECM) deposition were determined and the results compared with those obtained with cells encapsulated in non-functionalized alginate, and also those without perfusion. Staining for focal adhesions and actin showed maximal cell adhesion only for alginate-tetrameric FN scaffolds under perfusion, associated with a significant increase in cell number over 7 days culture; in contrast to poor cell adhesion and a decrease in cell number for non-functionalized alginate scaffolds (irrespective of perfused/static culture) and 3D static culture (irrespective of the scaffold). Conjugation of alginate to FN was an absolute requirement to attenuate the loss of cell metabolic activity over 7 days culture. ECM deposition for blank alginate and alginate-monomeric FN was similar, but increased around 2-fold and 3-fold for alginate-tetrameric FN under static and perfusion culture, respectively. It is concluded that the requirement for EnSC engagement with multivalent integrin α5β1 ligands and perfused culture are both essential as a first step toward endometrial tissue engineering.