Fig. 5.
Functional characterization of human PCCs. (A) S.c. injection of 5 × 106 PCCs in STZ-treated SCID mice promptly decreased their glucose blood levels. Glucose levels remained constant up to 133 d. Injection of the same number of untreated fibroblasts did not elicit any effect, and mice died after 4 wk. Removal of PCCs from STZ-treated mice caused a rapid rise in glycemic values, indicating that PCCs were the functional source of insulin. (B) I.p. injection of 3 g per kilogram body weight induced a rise of blood glucose concentration that returned to basal level within 90 min, both in PCC-engrafted and control mice. The test was repeated 3 times at 1-wk intervals. (C) Levels of human insulin in the serum of STZ-treated mice during PCC engraftment and after its removal. (D) Immunolocalization of C-peptide and glucagon in pancreatic islets of control and STZ SCID mice indicate the selective destruction of beta cells. (Scale bar, 20 µm.) Immunolocalization of C-peptide, glucagon, and somatostatin in human PCCs removed from SCID mice. Merged costaining demonstrates that each cell produces a single hormone. (Scale bar, 50 µm.)