title: Islet size index as a predictor of outcomes in clinical islet autotransplantation.
abstract: BACKGROUND
  The islet size distribution in a preparation may contribute to islet transplant outcomes. At the same islet equivalent (IE) dose, larger islets may exhibit poorer therapeutic value and this may be because of oxygen diffusion limitations that worsen in proportion to islet size.
  
  
  METHODS
  To test this hypothesis, we studied the impact of islet size index (ISI) and other islet product characteristics on outcomes after islet autotransplant (IAT) in recipients receiving a marginal islet dose (2000-4999 IEs per kg body weight) from January 1, 2009 to June 11, 2012, at the University of Minnesota (n=58). ISI was defined as the number of IE divided by the number of islet particles (IPs) in a preparation; an ISI less than 1 indicates a mean islet diameter that is less than 150 μm. The primary post-IAT outcome was 6-month insulin use status.
  
  
  RESULTS
  Logistic regression analysis indicate that IPs/kg (P=0.001), IEs/kg (P=0.019), total IPs transplanted (P=0.040), and ISI (P=0.074) were most strongly correlated with the primary outcome. The ISI (mean±standard error) was lower for recipients achieving insulin independence at 6 months (0.71±0.05) versus those partially (0.83±0.05) or completely (1.00±0.07) insulin dependent. The combination of islet dose (expressed as units IPs/kg) and ISI exhibited a sensitivity of 75% and specificity of 74% in predicting insulin independence in this population of patients.
  
  
  CONCLUSIONS
  Islet autotransplant recipients of a marginal islet doses were more likely to achieve insulin independence when transplanted with a greater number of smaller islets.
authors.affiliation: 1 Department of Surgery, University of Minnesota, Minneapolis, MN. 2 Institute for Cellular Transplantation, University of Arizona, Tucson, AZ. 3 Department of Pediatrics, University of Minnesota, Minneapolis, MN. 4 Address correspondence to: Melena D. Bellin, M.D., Schulze Diabetes Institute, Department of Surgery, University of Minnesota, 420 Delaware St SE, MMC 195, Minneapolis, MN 55455.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Suszynski
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Wilhelm
authors.forename: David M
authors.initials: DM
authors.lastname: Radosevich
authors.forename: A N
authors.initials: AN
authors.lastname: Balamurugan
authors.forename: David E R
authors.initials: DE
authors.lastname: Sutherland
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Beilman
authors.forename: Ty B
authors.initials: TB
authors.lastname: Dunn
authors.forename: Srinath
authors.initials: S
authors.lastname: Chinnakotla
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Pruett
authors.forename: Selwyn M
authors.initials: SM
authors.lastname: Vickers
authors.forename: Bernhard J
authors.initials: BJ
authors.lastname: Hering
authors.forename: Klearchos K
authors.initials: KK
authors.lastname: Papas
authors.forename: Melena D
authors.initials: MD
authors.lastname: Bellin
mesh_terms: D000328:Adult; D016009:Chi-Square Distribution; D003920:Diabetes Mellitus / Q000188:drug therapy / Q000209:etiology; D005260:Female; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D007328:Insulin / Q000627:therapeutic use; D007515:Islets of Langerhans / Q000473:pathology / Q000601:surgery*; D016381:Islets of Langerhans Transplantation / Q000009:adverse effects / Q000379:methods*; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D010180:Pancreatectomy / Q000009:adverse effects; D050500:Pancreatitis, Chronic / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014182:Transplantation, Autologous; D016896:Treatment Outcome
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin