Fig. 4. β-Cells were functional both in vitro and in vivo.

a Human C-peptide secretion from stage-7 (red filled circle), stage-8 (green box) cells, and primary human pancreatic islets (black triangle) in response to low (3.3 mM) and high (16.7 mM) glucose concentrations under static conditions. b Human C-peptide secretion from stage-8 cells in response to low glucose (3.3 mM, n = 5, red filled circle), Exendin-4 (with 3.3 mM glucose, n = 5, green box), high glucose (16.7 mM, n = 4, blue triangle), and 30 mM KCl (n = 4, black triangle). c Total insulin content of stage-8 cells (green box) and human islets (black triangle). d Stage-8 cells reversed the hyperglycemia in STZ-induced diabetic NSG mice. STZ was administrated ~5 weeks before cell transplantation. Tx, transplantation. N = 4 for experimental group and n = 3 for control groups. Transplanted fibroblasts were used as control. e Human C-peptide levels were measured after an overnight fasting and 60 min following an i.p. glucose bolus at 5 weeks post transplant of stage-8 end-point cells (n = 3 mice for each differentiation-and-transplantation batch). f Morphology of engraftments derived from different cells after transplantation in normal NSG mice, including stage-4, -7, and -8 cells, and undifferentiated H1 hPSCs. The blue arrows indicate engraftments. K, kidney. Data are presented as mean ± SEM for a, b, d, and e, and mean ± SD for c, respectively. P-values were determined by t-tests (two-sided) for a, b, d, and e. N.D., not detectable. N.S., not significant. The estimated purity of primary human pancreatic islets was about 70%. Source data are provided as a source data file. All the experiments repeated in a–d are biologically independent. Images of f are representative of three independent experiments.