Human gastric multi-regional assembloids for functional parietal maturation

Patient-derived human organoids have the remarkable capacity to self-organise into more complex structures. However, to what extent the gastric organoids can recapitulate the human stomach functions remains unexplored. Here, we report how gastric region-specific organoids can self-assemble into complex multi-regional assembloids showing levels of differentiation unattainable with simpler models. The assembloid shows preserved fundus, body and antrum regionality and gastric-specific crosstalk pathways arise. Remarkably, the increased complexity and cross communication between the different gastric regions, allows for the arise of the elusive parietal cell type, responsible for the production of gastric acid, the essential function for food digestion. We showed functional response to drugs targeting ATPase H+/K+ and further maturation of the assembloid when transplanted in vivo. This advanced in vitro model, using patient-derived tissue-specific progenitors, successfully recapitulates the structural and functional characteristics of the human stomach, offering a promising strategy for studying developmental processes, tissue interactions, and disease mechanisms that were previously challenging to attain.