Hurdles to Generating Human Islets in Animals via Blastocyst Complementation

Purpose of Review To clarify the hurdles to generation of human islets via blastocyst complementation and to identify techniques to overcome them. Recent Findings Blastocyst complementation is a promising method for generating functional islets from pluripotent stem cells which are identical to in vivo islets. Studies have reported successful generation of mouse pancreas in rats and rat pancreas in mice via interspecies blastocyst complementation and have shown the possibility for generation of human organs in xenogeneic animals. However, there remain hurdles to generating human islets in animals. Summary The major hurdles to generating human islets include difficulty in engineering human–animal chimeras due to the cellular status of human pluripotent stem cells, immunological rejection of donor tissue in xenogeneic animals, and ethical concerns.