The invention of culture conditions for long-term expansion of even a single LGR5⁺ intestinal stem cell as crypt-villus structures demonstrated the feasibility to derive complex organ-like structures invitro from primary adult tissues and initiated a wave of studies creating epithelial organoids from every germ layer. Moreover, human pluripotent stem cells (hPSCs) were applied to mimic lineage commitment and later on complemented with organoid-cultures to reach the respective maturation stage. The organ studied best in “organoid cultures” is the gut. Here human intestinal organoids or “mini-guts” are grown in a three-dimensional (3D) culturing system in matrigel and supplied with a specific set of growth factors. In this environment, isolated adult stem cells build crypt-like structures composed of diverse organ-specific cell types recapitulating human tissue architecture and the associated stem cell hierarchy responsible for rapid epithelial turnover and tissue homeostasis in the gut. Meanwhile similar studies were obtained for the pancreas, the lung, and the brain. Therefore these organoids are suitable not only for disease-modelling, drug validation, or engineering personalized therapy strategies, but also for studying tissue development, regeneration, and niche organization across several organs and stem cell niches.

In this special issue, we welcome review and original papers focussing on organoids either derived from adult stem cell compartments or differentiated from pluripotent stem cells. Here, such organoid studies should report on their capacity in disease modelling but also as a superior cell fate determination model. Additionally, we encourage reports on “disease-specific organoid papers,” “new strategies to develop organoid cultures,” “microfluidic or 3D printing approaches,” and their advantage to model disease, test drugs, and assess developmental changes.

Potential topics include but are not limited to the following:

• Novel culture conditions using organoids
• Organoids to assess developmental defects
• Organoids generated from other model organisms
• Organoids and tissue complexity
• Polarity and maturation in organoids
• Inherited and acquired disease in an organoid model
• Cancer organoids
• Organoids and individualized medicine
• 3D printing of tissues and their utilization
• Microfluidic devices and stem cell derived tissues