Editor's Note
Stanford Medicine scientists have successfully grown heart and liver organoids with functioning blood vessels, potentially overcoming one of the biggest limitations in organoid research: size. As reported in a June 6 article from News-Medical.net, the breakthrough may expand organoid utility for modeling disease, testing drugs, and advancing regenerative therapies.
Organoids (small, lab-grown clusters of cells that mimic organs) have been constrained by the lack of internal blood vessels. According to News-Medical.net, organoids larger than about 3 millimeters in diameter begin to die from the inside due to lack of oxygen and nutrient diffusion. But the new study, published June 5 in Science, describes how Stanford researchers produced heart organoids with a dense network of realistic, branching vessels capable of sustaining more complex tissue.
Using human pluripotent stem cells, the team designed 34 different “recipes” combining known techniques for generating cardiomyocytes, endothelial cells, and smooth muscle cells. They modified the stem cells to fluoresce in different colors based on which cell type they became. According to the article, the researchers identified one optimal recipe—condition 32—that produced organoids rich in all three desired cell types and visibly vascularized under 3D microscopy.
These donut-shaped organoids had outer layers of endothelial cells forming vessels just 10 to 100 microns in diameter, comparable to real capillaries, the outlet reports. The team also conducted single-cell RNA sequencing and found that each organoid contained 15 to 17 heart cell types, approaching the 16 found in a six-week embryonic heart and not far from the 21 in an adult heart.
The full report offers more detail on the potential of these organoids for early human development, especially in ethically controversial research areas, as well as ambitions from future work and the researcher’s broader potential for therapeutic implantation.
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