Type 1 diabetes is caused by the immune system attacking the cells that produce insulin. In a new diabetic it takes on the order of 6-18 months to kill enough cells to make someone diabetic. Replacing the cells would be a very temporary fix. I do wonder —- if this technology was arbitrarily cheap, would there be a downside to just “topping up” the cells every month or so? Or would stoking a constant immune response cause other issues?