FIG. 3.

Histological analysis of islet allografts at day 14 after transplantation in untreated mice (hyperglycemic) revealed complete destruction of the graft parenchyma (A) and absent insulin (E) and glucagon (F) staining, with diffuse infiltration primarily constituted by CD3⁺ (B) and MAC2⁺ (D) cells, with very few FoxP3⁺ cells (C); conversely in oATP-treated mice (normoglycemic), islet allograft structure (G), and insulin (K) and glucagon (L) staining were preserved, with mild infiltrate mainly confined to the islet borders (H, J) with several FoxP3⁺ cells (I) (representative of different mice). Semi-quantification of insulin staining confirmed enhanced preservation of islet allografts in oATP-treated mice (n = 5, **P < 0.01 vs. untreated at day 14) (M), with no significant differences in cell infiltrate (N). A reduction in Tbet (n = 3, *P < 0.05 vs. untreated at day 14) (O), but not of Rorc transcripts (P), was evident in islet allografts obtained from oATP-treated islet-transplanted mice compared with untreated mice. Insulin (n = 5 for untreated and n = 10 for oATP-treated; **P < 0.01) (Q) and glucagon content (n = 5 for untreated and n = 6 for oATP-treated; **P < 0.01) (R) resulted higher in transplanted islets harvested from oATP-treated compared with untreated recipients.