From ViaCyte Reports on Stem Cell Diabetes Trial, Absorbs BetaLogics:

ViaCyte bio-engineered packet VC-01 shows vasculature
ViaCyte bio-engineered packet VC-01 shows vasculature

In preclinical studies, explants of ViaCyte’s bio-engineered packet implanted
in mice became vascularized and human insulin from matured PEC-01 cells could be released in the blood stream. (ViaCyte photo used with permission)