Stamceller specialiseras i flera steg
To make a β cell, you have to first convert ES cells into mesendoderm, then into endoderm, then into Anterior Definitive Endoderm (ADE), then into midgut endoderm, then into general pancreatic tissue, then into pancreatic endocrine cells, and finally, you can apply a signal to switch them into the β cell state. This is a non-trivial problem in a dish.
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