Assessment of the in vitro function of human stem cell-derived β cells

Insulin-producing human embryonic stem cell-derived β (SC-β) cells are a promising cell source for diabetes cell replacement therapy. We have recently reported a differentiation strategy that produces SC-β cells in islet organoids that not only undergo glucose-stimulated insulin secretion but also have an islet-like dynamic insulin release profile, displaying both first and second phase insulin secretion. The goal of this study was to further characterize the functional profile of these SC-β cells in vitro . We utilized a Seahorse extracellular flux analyzer to measure mitochondrial respiration of SC-β cells at low and high glucose. We also used photolithography to fabricate a microfluidic device containing microwells to immobilize SC-β cells for perfusional analysis, monitoring cytoplasmic calcium using Fluo-4 AM at low and high glucose. Here we find that in addition to increased insulin secretion, SC-β cells have increased cellular respiration and cytoplasmic calcium ion concentration in response to a high glucose stimulation. Our results indicate that SC-β cells have similar function to that reported for islets, providing further performance characterization that could help with eventual development for diabetes cell therapy and drug screening.