Brassard, J. A. | bioRxiv Science

bioRxiv2025

Human pancreatic organoids derived from pluripotent stem cells recapitulate pancreatic organogenesis

Pancreas organogenesis relies on sequential interactions between the pancreatic epithelium and surrounding mesodermal cell types that initiate epithelial budding and branching to form a complex ductal network with terminal acini. Despite recent advances with pluripotent stem cell-based approaches, there are no models that robustly recapitulate pancreas morphogenesis or the spatial organization of ductal, exocrine, endocrine and mesenchymal cells seen in the native organ. Here, we introduce a new pluripotent stem cell-based pancreatic organoid that captures the complexity seen during pancreatic development, with budding and stratification of multipotent progenitors followed by formation of a ductal network that give rise to peripheral acini. We identify a critical role for mesenchyme-derived factors to robustly promote pancreatic organoid formation and morphogenesis. Human pancreatic organoids are correctly patterned, with functional exocrine acini secreting digestive enzymes into a ductal network. Comparative analysis confirms that the pancreatic organoids are similar to early second trimester human pancreas, with potential to further mature upon transplantation in mice. Finally, we show that endocrinogenesis can be reproduced in organoids, generating functional islet-like clusters interspersed within the ductal network. Together, this represents an exciting new platform to study human pancreas development and a broad array of pancreatic diseases.

developmental biology↗

bioRxiv2024

Iterative sacrificial 3D printing and polymer casting to create complex vascular grafts and multi-compartment bioartificial organs

Several emerging strategies to engineer artificial organs employ 3D printing to create vascular templates to provide nutrients and oxygen to immobilized cells. Significant challenges emerge when considering clinical implementation such as immune rejection of allogeneic cell sources, as well as achieving adequate perfusion and integration with endogenous vasculature. We propose a method by which cell-laden hydrogels are molded around ready-made polymeric vascular templates created via 3D printing to create human-scale artificial organs with internal vasculature. We applied this technique to create bioartificial pancreas systems with up to 9 internal flow channels via sacrificial carbohydrate glass 3D printing, porogen-loaded polycarbonate polyurethane dip-coating, followed by casting cell-laden hydrogels around the vascular templates. We optimized porogen size and concentration to maximise the porosity of our scaffolds without compromising mechanical properties, resulting in suture retention strength and compliance respectively matching commercial vascular grafts and native vessels. Bioreactor perfusion studies showed survival and maturation of stem cell derived pancreatic islets without significant differences to traditional suspension culture protocols. Insulin response dynamics were rapid in response to a glucose challenge at the perfusion inlet. Transplantation of the devices as iliac arteriovenous shunts in nondiabetic pigs confirmed safety and patency. These results show promise for the development of an implantable vascularized pancreas for the treatment of type 1 diabetes and demonstrate how bioartificial organs with engineered vascular geometries can be designed for translational applications.

bioengineering↗