Human Cord Blood–Derived Cells Generate Insulin‐Producing Cells In Vivo

Here we report the capacity of human cord blood (CB)–derived cells to generate insulin‐producing cells. To investigate in vivo capacity of human CB–derived cells, T cell–depleted mononuclear cells were intravenously transplanted into nonobese diabetic/severe combined immunodeficient/β 2 ‐microglobulin null mice within 48 hours of birth. At 1–2 months post‐transplantation, immunofluorescence staining for insulin and fluorescence in situ hybridization (FISH) analysis using a human chromosome probe indicated that human CB–derived cells generated insulin‐producing cells at a frequency of 0.65% ± 0.64% in xenogeneic hosts. Reverse transcription–polymerase chain reaction analysis confirmed the transcription of human insulin in the pancreatic tissue of the recipient mice. To clarify the mechanism underlying CB‐derived insulin‐producing cells, double FISH analysis using species‐specific probes was performed. Almost equal proportions of human chromosome + murine chromosome − insulin + cells and human chromosome + murine chromosome + insulin + cells were present in recipient pancreatic islets. Taken together, human CB contains progenitor cells, which can generate insulin‐producing cells in recipient pancreatic tissues across a xenogeneic histocompatibility barrier by fusion‐dependent and ‐independent mechanisms.