Figure 5 A Representative 3D images with Insulin and Caveolin-1 immunostaining in pancreatic islets from young mice. Combined box and whiskers, and scatter plots show the vessel density analysis in the pancreatic islets and non-islet areas from young and aged mice. Data information: The white and dashed lines in panel A, B, D, F, H and I represent the outlines of pancreatic islets. (n=5), P-values, and two-tailed unpaired t-tests in panel (A, E and I) and one-way ANOVA tests with Tukey's multiple comparisons tests in panel (G and H). *: P < 0.05; **: P < 0.01; ***: P < 0.001; ****: P < 0.0001. Nuclei: TO-PRO-3. Is: pancreatic islet. f.u: fluorescence unit.  B Representative 3D images with adult pancreatic islets immunolabeled with Ki67 and VE-Cadherin. Inset (*) shows single-cell resolution and surface rendering for all the channels. Data information: The white and dashed lines in panel A, B, D, F, H and I represent the outlines of pancreatic islets. (n=5), P-values, and two-tailed unpaired t-tests in panel (A, E and I) and one-way ANOVA tests with Tukey's multiple comparisons tests in panel (G and H). *: P < 0.05; **: P < 0.01; ***: P < 0.001; ****: P < 0.0001. Nuclei: TO-PRO-3. Is: pancreatic islet. f.u: fluorescence unit.  C Representative tile scan 3D image with Insulin, ESM-1 and Emcn immunostaining in 19-weeks-old mouse pancreas. Higher magnification at the top of the right panel shows the ESM-1+ pancreatic islets. Inset (*) shows single-cell resolution and surface rendering for ESM-1 and Emcn. The white and dashed line in the tile scan image represents the outline of one lobe of the pancreas, and the dashed lines in the inset represents the pancreatic islet. Data information: The white and dashed lines in panel A, B, D, F, H and I represent the outlines of pancreatic islets. (n=5), P-values, and two-tailed unpaired t-tests in panel (A, E and I) and one-way ANOVA tests with Tukey's multiple comparisons tests in panel (G and H). *: P < 0.05; **: P < 0.01; ***: P < 0.001; ****: P < 0.0001. Nuclei: TO-PRO-3. Is: pancreatic islet. f.u: fluorescence unit. D Representative 3D images show CD31 and Emcn expressions in young pancreas. Insets (* and #) show higher magnifications of capillaries in the pancreatic islets and non-islet areas. Data information: The white and dashed lines in panel A, B, D, F, H and I represent the outlines of pancreatic islets. (n=5), P-values, and two-tailed unpaired t-tests in panel (A, E and I) and one-way ANOVA tests with Tukey's multiple comparisons tests in panel (G and H). *: P < 0.05; **: P < 0.01; ***: P < 0.001; ****: P < 0.0001. Nuclei: TO-PRO-3. Is: pancreatic islet. f.u: fluorescence unit. E Representative flow cytometry dot plots showing CD31+ Emcnhi and CD31+ Emcnlo EC populations in young and aged pancreas. Combo plot shows the population of CD31+ Emcnhi ECs in young and aged pancreas.  F Representative 3D images (left) with Insulin, Ki67 and VE-Cadherin immunostaining on young and aged pancreas. 3D images (middle) show CXCR4, Ki67 and VE-Cadherin in young and aged pancreatic islet. Insets (yellow asterisks) show single-cell resolution and surface rendering for Ki67 and CXCR4. Arrowheads represent Ki67+ β-cell. G Combo plot shows the quantification of Ki67+ β-cells normalized to the total number of β-cells per islet in juvenile (3-weeks-old), adult (12-weeks-old) and aged (55-weeks-old) pancreatic islets. Data information: The white and dashed lines in panel A, B, D, F, H and I represent the outlines of pancreatic islets. (n=5), P-values, and two-tailed unpaired t-tests in panel (A, E and I) and one-way ANOVA tests with Tukey's multiple comparisons tests in panel (G and H). *: P < 0.05; **: P < 0.01; ***: P < 0.001; ****: P < 0.0001. Nuclei: TO-PRO-3. Is: pancreatic islet. f.u: fluorescence unit. H Representative 3D images with Insulin, CD31 and Emcn immunostaining in young and aged pancreas. Combo plot shows the CD31+ Emcnhi vessel density in juvenile, adult and aged pancreatic islets. Data information: The white and dashed lines in panel A, B, D, F, H and I represent the outlines of pancreatic islets. (n=5), P-values, and two-tailed unpaired t-tests in panel (A, E and I) and one-way ANOVA tests with Tukey's multiple comparisons tests in panel (G and H). *: P < 0.05; **: P < 0.01; ***: P < 0.001; ****: P < 0.0001. Nuclei: TO-PRO-3. Is: pancreatic islet. f.u: fluorescence unit.  I Representative 3D images of adult (10-weeks-old) and aged pancreas (55-weeks-old) with Insulin and VEGFA immunostaining. Combo plot (middle) shows the VEGFA as determined by ELISA assay in isolated islets from 10-weeks-old adult and 55-weeks-old aged mice. Combo plot (right) shows the percentage of VEGFA per islet (f.u). Data information: The white and dashed lines in panel A, B, D, F, H and I represent the outlines of pancreatic islets. (n=5), P-values, and two-tailed unpaired t-tests in panel (A, E and I) and one-way ANOVA tests with Tukey's multiple comparisons tests in panel (G and H). *: P < 0.05; **: P < 0.01; ***: P < 0.001; ****: P < 0.0001. Nuclei: TO-PRO-3. Is: pancreatic islet. f.u: fluorescence unit.