Advances in Internal Organogenesis: Differentiation and Morphogenesis of Human Ventral Cavity Organs.

Regenerative medicine promises the possibility of custom-made, ready-to-use human organs without the risk of immune rejection. Human pluripotent stem cells (hPSCs) are the workhorses of stem cell-based tissue engineering. With inherent capabilities to adopt nearly any cellular form, they are supposed to solve the soaring demand for transplantable organs. Technically, PSCs are converted into cells of interest using a stepwise approach (differentiation) mimicking embryonic development. Animal models have been crucial in advancing our understanding of human embryology, mainly due to the widespread conservation of the mammalian regulome. Differentiation protocols have evolved with time from two-dimensional (2D) monocultures, which are relatively easy to maintain, to more complex three-dimensional (3D) organoids that enhance the capacity for staging multilineage assemblies. The appeal of 3D systems lies in their operational resemblance to the actual morphology of tissues. While each platform has pros and cons, its specific strengths can be leveraged to tell a more compelling story of development and how complex pathologies take root. Here, we reviewed key methodologies for the in vitro production of human functional cell lineages from hPSCs. We have connected the most recent science to the work that came before and analyzed where the trends we see now might lead. We examined the shift from 2D cell monolayers to 3D organoids. Additionally, we highlighted hybrid approaches and innovative discoveries that support the reliable generation of physiologically mature cells, enabling the study of development and disease at new depths.