Figure 10.

Photomicrographs illustrating features of neogenic α-, β-and δ-cells in wild-type (a, b) and PC2-ko animals (c–f). (a) GLP-1 immunostaining showing peripheral distribution of red-stained, α-cells in this islet and also the location of a small cluster and a single cell within and subjacent to the pancytokeratin-immunostained pancreatic ductal epithelium (brown), (b) increased magnification showing close association between a single GLP-1-positive cell with the pancytokeratin-stained pancreatic ductule indicating the potential for endocrine cell neogenesis in ducts of all dimensions, (c) a duct situated adjacent to an α-cell adenoma stained with GLP-1 shows single α-cell or α-cell clusters lying within or subjacent to the ductal epithelium, (d) clusters of somatostatin-immunostained cells associated with ductal epithelium, (e) dual-insulin-(red) and GLP-1 (brown)-immunostained pancreas showing red-stained β-cells in islet associated with hypertrophic/hyperplastic α-cells with individual cells within and subjacent to the ductal epithelium, (f) dual GLP-1 (red) and somatostatin (brown)-immunostained pancreas showing hypertrophic/hyperplastic α-cells in islet associated with δ-cells and with similarly-stained individual cells in adjacent duct within and subjacent to the ductal epithelium, (g) vimentin immunostaining showing multiple ductal cells showing strong positivity (arrows). No or very few such stained cells were present in most WT and PC2-ko animals, (h) dual Ki-67 (red nuclei) and GLP-1 immunostaining (brown cytoplasm) showing multiple Ki-67-positive exocrine cells at different stages of mitotic cycle around an islet with several Ki-67/GLP-1-positive α-cells (arrows). (Objective lens magnifications: a, c, g ×20; b ×63, d–f, h ×40).