During the second year of our grant we have determined two important features:
1- The encapsulation device we assessed here allows for the efficient development of functional insulin-producing grafts derived from differentiated human embryonic stem cells. We show that in the vast majority of implanted mice (93%) robust insulin-production was detected. Moreover, supporting their potential therapeutic value, in 19 of 19 animals that were challenged with the chemical destruction of their own insulin-producing cells the encapsulated grafts prevented the onset of diabetes.
2- We have used an imaging technology and genetically modified human embryonic stem cells to assess the grafts of differentiated embryonic stem cells in animals as the functional insulin delivery capacity develops over time. These studies showed that the encapsulation device fully contains the grafts: no hESC-derived cells were found outside of the implanted encapsulation device. This supports the premise that the device can be used to safely administer a population of cells derived from hESC.