title: Intramedullary cavity as implantation site for bioartifical pancreas: preliminary in vivo study.
abstract: BACKGROUND
  The intramedullary cavity is a widely distributed well-vascularized microenvironment capable of sustaining grafts, and is a potential site for islet transplantation. The bone marrow offers sufficient space that may also be suitable for bioartificial pancreas (BAP) implantation.
  
  
  OBJECTIVE
  To evaluate the feasibility of bone marrow as an implantation site for BAPs.
  
  
  METHODS
  A calcium phosphate cement chamber satisfies the criteria for immunoisolation. Mouse insulinoma cells were suspended with agarose gel and enclosed in a calcium phosphate cement chamber to create a BAP, which was implanted in the intramuscular space in diabetic swine or the intramedullary cavity in diabetic dogs. Blood glucose and C-peptide concentrations were determined perioperatively.
  
  
  RESULTS
  In the swine, the mean ± SD blood glucose concentration decreased from 413 ± 24 mg/dL to 285 ± 47 mg/dL, and was maintained in the range of 285 to 336 mg/dL for 15 days. It increased to 368 to 450 mg/dL after the BAPs were implanted in the intramuscular space. In the dogs, the blood glucose concentration decreased from 422 ± 32 mg/dL to 247 ± 52 mg/dL, and was maintained in the range of 247 to 347 mg/dL after the BAPs were implanted in the intramedullary cavity. The C-peptide concentration increased from 6.1 ± 2.8 pmol/L to 104.7 ± 16.4 pmol/L when the BAPs were implanted in the intramedullary cavity.
  
  
  CONCLUSIONS
  This study indicates superior effectiveness of BAPs implanted in the intramedullary cavity compared with the intramuscular space. This observation may be attributed to the greater oxygen tension in the bone marrow. The BAPs in direct contact with the circulatory system receive sufficient blood flow for function and survival. This preliminary study demonstrates that the intramedullary cavity may be an implantation site for BAP transplantation.
authors.affiliation: Department of Organ Reconstruction, Institute for Frontier Medical Sciences, Kyoto University, Japan.
authors.forename: K-C
authors.initials: KC
authors.lastname: Yang
authors.forename: C-C
authors.initials: CC
authors.lastname: Wu
authors.forename: Z-F
authors.initials: ZF
authors.lastname: Kuo
authors.forename: C-Y
authors.initials: CY
authors.lastname: Yang
authors.forename: F-H
authors.initials: FH
authors.lastname: Lin
mesh_terms: D000818:Animals; D021522:Bioartificial Organs / Q000706:statistics & numerical data*; D001786:Blood Glucose / Q000378:metabolism; D001843:Bone Cements; D001853:Bone Marrow / Q000033:anatomy & histology; D002096:C-Peptide / Q000097:blood; D004285:Dogs; D007340:Insulinoma / Q000473:pathology* / Q000601:surgery; D007679:Kidney Medulla / Q000601:surgery*; D051379:Mice; D016035:Pancreas Transplantation / Q000379:methods*; D019736:Prostheses and Implants / Q000706:statistics & numerical data; D013552:Swine
chemical_list: D001786:Blood Glucose; D001843:Bone Cements; D002096:C-Peptide