Figure 3.

Nodal stimulates human β-cell proliferation while inhibiting α-cell proliferation. Flow cytometry analysis of human islets trypisinized to single cells after 120 hours of exposure to Cripto (250 ng/mL) and/or Nodal (10 μg/mL). Cells were stained for insulin, glucagon, and BrdU to evaluate for proliferating β- and α-cells in Cripto- and/or Nodal-treated groups compared with controls. A, Gating strategy used for flow cytometry analysis. Viable cells, cells that did not take up Live/Dead stain, were gated for insulin and glucagon positive cells (red arrow). Endocrine cells were further gated for double-positive insulin +/BrdU+ (blue arrow) or glucagon+/BrdU+ (green arrow), indicating the proliferating subset of β and α-cells. (BrdU isotype is shown.) B, Comparison of proliferating β-cells in Cripto- and/or Nodal-treated islets compared with control. A total of 3773 ± 577 β-cells were counted per treatment group per experiment (n = 5). C, Comparison of proliferating α-cells in Cripto- and/or Nodal-treated islets compared with control. A total of 5707 ± 961 α-cells were counted per treatment group per experiment (n = 4). Bars indicate mean ± SEM. *, P < .05.