Fig. 2.

Altered islet microvasculature in islets from AktTg mice. (a) Representative maximal projections of confocal images of pancreases from C57BL/6 wild-type (WT) and AktTg mice showing blood vessels covered with pericytes. Blood vessels were labelled with a fluorescent lectin from Lycopersicon esculentum (red) and pericytes immunostained for NG2 (green). Increased pericyte coverage of AktTg islet capillaries is visible. Pericyte coverage of blood vessels in the acinar tissue in AktTg mice is apparently similar to that of wild-type acinar tissue. (b) Representative maximal projections of confocal images of blood vessels in islets from wild-type and AktTg mice showing pericytes and endothelial cells immunostained, respectively, for NG2 (green) and for CD31 (PECAM, red). Cell nuclei were labelled with DAPI (blue). Pericytes nicely cover capillaries in wild-type islets but their coverage is increased in AktTg islets. Pericytes and capillaries in the acinar tissue of AktTg mice are not different from wild-type acinar vessels. (c) Quantification of the area covered with blood vessels (immunostained with an anti-CD31 antibody) in islets and surrounding acinar tissue in wild-type and AktTg pancreases, divided by the total area (shown as %). *p<0.05 (unpaired t test; n=3–5 islets/mouse, 3 mice per genotype). (d, e) Quantification of the total number of (d) NG2-labelled pericytes, or (e) CD31 labelled endothelial cells in confocal sections of islets from wild-type and AktTg mice, divided by the islet area and multiplied by a mean islet area of 10,000 μm². *p<0.05 (unpaired t test; n=3 confocal planes/islet, 5 islets/mouse, 3 mice per genotype). (f) Quantification of the ratio of pericyte number to endothelial cell number in confocal sections of wild-type and AktTg islets. *p<0.05 (unpaired t test; n=3 confocal planes/islet, 5 islets/mouse, 3 mice per genotype). (g) Representative maximal projections of confocal images of pericytes in wild-type and AktTg islets showing pericytes immunostained for NG2 (green) and PDGFRβ (red). Increased number of pericytes are present in AktTg islets. Scale bars, 100 μm (a) and 10 μm (b, g)