title: Histologic graft assessment after clinical islet transplantation.
abstract: BACKGROUND
  An accurate monitoring would help understanding the fate of islet grafts after transplantation.
  
  
  METHODS
  This work assessed the feasibility of needle biopsy monitoring after intraportal islet transplantation (n=16), and islet graft morphology was studied with the addition of autopsy samples (n=2). Pancreas autopsy samples from two nondiabetic individuals were used as control.
  
  
  RESULTS
  Islet tissue was found in five needle samples (31%). Sampling success was related to size (100% sampling for the four biopsies of 1.8 cm in length or higher, P<or=0.01). Mild liver abnormalities included localized steatosis (n=8), mild nodular regenerative hyperplasia and mild portal venopathy (n=3), and hepatocyte swelling (n=2). Endocrine cell composition and distribution were similar between islet grafts and normal islets within the native pancreas. There was no or minimal immune cell infiltrate in patients on and off exogenous insulin, including two patients with ongoing negative metabolic events (increasing HbA1c or insulin requirement). The infiltrate was mainly composed of CD4- and CD8-positive cells.
  
  
  CONCLUSIONS
  This study demonstrates that needle biopsy is feasible after clinical islet transplantation but with a limited practical value because of its low islet sampling rate using current sampling and analysis methods. Both biopsy and autopsy samples demonstrated the well-preserved islet endocrine composition after transplantation and the presence of focal areas of steatosis. Islet grafts showed no or minimal immune cell infiltration, even in the case of ongoing islet loss. On the basis of the findings, possible reasons for allograft islet loss are discussed.
authors.affiliation: Clinical Islet Transplant Program, University of Alberta, Edmonton, AB, Canada. christian.toso@hcuge.ch
authors.forename: Christian
authors.initials: C
authors.lastname: Toso
authors.forename: Kumiko
authors.initials: K
authors.lastname: Isse
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Demetris
authors.forename: Parastoo
authors.initials: P
authors.lastname: Dinyari
authors.forename: Angela
authors.initials: A
authors.lastname: Koh
authors.forename: Sharleen
authors.initials: S
authors.lastname: Imes
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kin
authors.forename: Juliet
authors.initials: J
authors.lastname: Emamaullee
authors.forename: Peter
authors.initials: P
authors.lastname: Senior
authors.forename: A M James
authors.initials: AM
authors.lastname: Shapiro
mesh_terms: D000328:Adult; D001344:Autopsy; D001707:Biopsy, Needle; D016022:Case-Control Studies; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology / Q000473:pathology / Q000601:surgery*; D005240:Feasibility Studies; D005260:Female; D006084:Graft Rejection / Q000276:immunology / Q000473:pathology; D006801:Humans; D007515:Islets of Langerhans / Q000276:immunology / Q000473:pathology* / Q000601:surgery*; D016381:Islets of Langerhans Transplantation / Q000009:adverse effects; D008099:Liver / Q000276:immunology / Q000473:pathology* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013997:Time Factors; D014184:Transplantation, Homologous; D018084:Ultrasonography, Interventional