title: A secretory function of human insulin-producing cells in vivo.
abstract: BACKGROUND
  Mesenchymal stem cells derived from human umbilical cord blood (UCB-MSCs) have good research and application prospects in the treatment of diabetes. We once induced UCB-MSCs to differentiate into insulin-producing cells (IPCs) in vitro, but we did not know the functions of these cells in vivo. The aim of this study was to assess the functional effects of IPCs on insulin secretion and their role in the treatment of diabetes in vivo.
  
  
  METHODS
  UCB-MSCs were induced to IPCs by an inducing protocol with extracellular matrix gel. BALB/C nude mice were made hyperglycemic by intraperitoneal injection of streptozotocin. The diabetic mice were transplanted with 1X10(7) IPCs under the renal capsule or with phosphate-buffered saline as a control. After transplantation, the grafts were analyzed by immunocytochemistry for the expression of human insulin; the serum human insulin levels were measured; and blood glucose and body weight status were monitored.
  
  
  RESULTS
  Immunofluorescence showed that numerous IPCs under the kidney capsule were insulin-positive. On day 14 after transplantation, the serum human insulin level of the treatment group (n=9) averaged 0.44+/-0.12 mU/L, which was higher than that of the control group (n=9) that did not express insulin (t=10.842, P<0.05). The diabetic mice remained hyperglycemic and kept losing body weight after IPC transplantation, and there was no significant difference in the control group.
  
  
  CONCLUSIONS
  IPCs differentiated from UCB-MSCs generate human insulin in diabetic mice, but more research is needed to make further use of them to regulate hyperglycemia and body weight in vivo.
authors.affiliation: Department of General Surgery, Second Affiliated Hospital, Harbin Medical University, Harbin, China.
authors.forename: Yan-Hua
authors.initials: YH
authors.lastname: Hu
authors.forename: De-Quan
authors.initials: DQ
authors.lastname: Wu
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Guo-Dong
authors.initials: GD
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Yao
authors.forename: Xin-Chen
authors.initials: XC
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight; D002454:Cell Differentiation; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*; D005312:Fetal Blood / Q000166:cytology; D005456:Fluorescent Dyes; D006801:Humans; D007150:Immunohistochemistry; D007211:Indoles; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000378:metabolism* / Q000637:transplantation*; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology; D051379:Mice; D008807:Mice, Inbred BALB C
chemical_list: D001786:Blood Glucose; D005456:Fluorescent Dyes; D007211:Indoles; D007328:Insulin; C007293:DAPI