Do the human umbilical cord blood CD34+ progenitor cells home in the pancreas and kidney of diabetic mice?

Type 1 diabetes is a chronic metabolic disorder in which pancreatic islet β cells are irreversibly destroyed by autoimmunity. Many studies suggest great promise for the utility of human umbilical cord blood (HUCB) stem cells as a cure for diabetes; however, the mechanism for their effect requires further elucidation. This study investigated the presence of human DNA in the pancreas and kidney of diabetic mice treated with HUCB CD34+ cells. Eighteen albino male mice were equally and randomly divided into three groups: normal control group, diabetic untreated streptozotocin (STZ) group, and diabetic STZ-treated group. Diabetes was induced by intraperitoneal (IP) injection of STZ (180 mg/kg). CD34+ progenitor cells were separated from HUCB and injected intravenously in dose of 10⁶ cells/mouse. Blood glucose was measured every 2 days for 3 weeks. Mice were sacrificed after 3 weeks, and real-time PCR analysis was conducted for the presence of human-specific ALU sequence in the pancreata and kidneys from all animals. Injection of CD34+ cells caused significant improvement in blood glucose level (230 ± 50 mg/dl in treated group vs. 590 ± 24 mg/dl in untreated group, p = 0.001). Real-time PCR analysis showed negative results in the control and untreated groups, while in the treated group, engraftment of the HUCB CD34 cells was positive in 100 % of the kidneys with a mean transplanted cell percentage 1.8 ± 0.98 % and 66 % of the pancreata with a mean 0.41 ± 0.42 %. A significant negative correlation was found between the concentration of the ALU sequence in the pancreata and the change of glucose level in the treated group (p value =0.03 and r = −0.6). HUCB CD34 cells engraft in the pancreas of the diabetic mice and improve hyperglycemia. Based on our results, HUCB CD34 cell transplantation may provide a potential therapy for human diabetes mellitus.