For this reason, islet transplantation is currently limited to patients who suffer from severe and unstable T1D, have multiple episodes of hypoglycemia unawareness/glycemic lability, and are not capable of stabilizing the disease even with intensive insulin treatment including pumps and/or glucose-monitoring therapies (Shapiro, 2012; Mohsen et al., 2015; Hering et al., 2016; Shapiro et al., 2017; Markmann et al., 2021). Here, INS is linked to type 1 diabetes mellitus.