Figure 7.

β-Cell scaffold implantation does not induce diabetes. β-Cell or control scaffolds were implanted in NOD mice at 10 weeks of age, and weekly glucose measurements were taken until the age of 40 weeks. A: A Kaplan-Meier plot shows diabetes incidences in mice that were transplanted with either β-cell or control scaffolds. Diabetes was defined as two consecutive blood glucose readings >250 mg/dL. In each group, 10 mice were followed for diabetes development. B: Representative pancreas sections illustrate islet leukocytic infiltration and the determination of insulitis score. Islets were rated 0–4 according to the level of leukocytic infiltration. NOD mice were implanted with β-cell or control scaffolds, and insulitis scores were determined 14 days after implantation. Scale bars = 20 μm. The first cohort of mice was implanted at 9 weeks, and insulitis scores (C) and insulitis indexes (D) were determined at 11 weeks. The second cohort was implanted at 15 weeks, and insulitis scores (E) and insulitis indexes (F) were determined at 17 weeks. The third cohort was implanted at 22 weeks, and insulitis scores (G) and insulitis indexes (H) were determined at 24 weeks. Insulitis index: I = (0 × number of score 0) + (1 × number of score 1) + (2 × number of score 2) + (3 × number of score 3) + (4 × number of score 4)/(total number of scored islets). From each group of β-cell or control scaffolds, 63–113 islets were scored. Scaf^β-cell, β-cell scaffolds; Scaf^Ctrl, control scaffolds.