Lung organoids for preclinical evaluation of stem cell therapies: Opportunities, evidence, and translational challenges

Figure 1 Stem cell sources for lung organoid generation and the role of mesenchymal stromal cells as therapeutic modulators. This figure presents a conceptual schematic distinguishing two distinct categories of cells relevant to lung organoid research. Left side: Major stem cell sources used for lung organoid generation - including adult stem cells, induced pluripotent stem cells, and embryonic stem cells. Right side: Mesenchymal stromal cells are not used as starting cells for epithelial lung organoid formation. This is a conceptual framework proposed by the authors, not an evidence-based algorithm. ASC: Adult stem cell; iPSC: Induced pluripotent stem cell; ESC: Embryonic stem cell; MSC: Mesenchymal stromal cell; EVs: Extracellular vesicles.