In this context, we found a higher percentage of bi-hormonal cells expressing insulin and glucagon in both one- and four-week diabetic RIP-B7.1 mice, substantiating previous reports showing that alpha-to-beta cell transdifferentiation could be an important spontaneous route of beta-cell regeneration in several EAD mouse models22,24,28,38,39 and in human T1D subjects16,40. This evidence concerns the gene CD80 and type 1 diabetes mellitus.