Biology subjects

Millman, J. R.

Publications and source records attributed to Millman, J. R..

2 recordsLinked to original sources

bioRxiv2019

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

Insulin-producing human embryonic stem cell-derived {beta} (SC-{beta}) cells are a promising cell source for diabetes cell replacement therapy. We have recently reported a differentiation strategy that produces SC-{beta} 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-{beta} cells in vitro. We utilized a Seahorse extracellular flux analyzer to measure mitochondrial respiration of SC-{beta} cells at low and high glucose. We also used photolithography to fabricate a microfluidic device containing microwells to immobilize SC-{beta} 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-{beta} cells have increased cellular respiration and cytoplasmic calcium ion concentration in response to a high glucose stimulation. Our results indicate that SC-{beta} 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.

bioengineering↗

bioRxiv2019

Hydrogel platform for in vitro three-dimensional assembly of human stem cell-derived β cells and endothelial cells

Differentiation of stem cells into functional replacement cells and tissues is a major goal of the regenerative medicine field. However, one limitation has been organization of differentiated cells into multi-cellular, three-dimensional assemblies. The islets of Langerhans contain many endocrine and non-endocrine cell types, such as insulin-producing {beta} cells and endothelial cells. Transplantation of exogenous islets into diabetic patients can serve as a cell replacement therapy, replacing the need for patients to inject themselves with insulin, but the number of available islets from cadaveric donors is low. We have developed a strategy of assembling human embryonic stem cell-derived {beta} cells with endothelial cells into three-dimensional aggregates on a hydrogel. The resulting islet organoids express {beta} cell markers and are functional, capable of undergoing glucose-stimulated insulin secretion. These results provide a platform for evaluating the effects of the islet tissue microenvironment on human embryonic stem cell-derived {beta} cells and other islet endocrine cells to develop tissue engineered islets.

bioengineering↗