title: Endocrine secretory reserve and proinsulin processing in recipients of islet of langerhans versus whole pancreas transplants.
abstract: OBJECTIVE
  β-Cells have demonstrated altered proinsulin processing after islet transplantation. We compare β-cell metabolic responses and proinsulin processing in pancreas and islet transplant recipients with respect to healthy control subjects.
  
  
  METHODS
  We studied 15 islet and 32 pancreas transplant recipients. Islet subjects were subdivided into insulin-requiring (IR-ISL, n = 6) and insulin-independent (II-ISL, n = 9) groups. Ten healthy subjects served as control subjects. Subjects were administered an intravenous arginine stimulation test, and insulin, C-peptide, total proinsulin, intact proinsulin, and proinsulin fragment levels were determined from serum samples. Acute insulin response (AIR) and proinsulin processing rates were calculated.
  
  
  RESULTS
  We found that basal insulin and C-peptide levels were higher in the pancreas group than in all other groups. II-ISL patients had basal insulin and C-peptide levels similar to healthy control subjects. The IR-ISL group had significantly lower AIRs than all other groups. Basal processing rates were higher in the pancreas and II-ISL groups than in healthy control subjects and the IR-ISL group. After arginine stimulation, all groups had elevated processing rates, with the exception of the IR-ISL group.
  
  
  CONCLUSIONS
  Our data suggest that II-ISL transplant recipients can maintain basal metabolic parameters similar to healthy control subjects at the cost of a higher rate of proinsulin processing. IR-ISL transplant recipients, on the other hand, demonstrate both lower insulin response and lower basal rates of proinsulin processing even after arginine stimulation.
authors.affiliation: Corresponding author: Nabeel M. Elkhafif, nelkhafif@hotmail.com.
authors.forename: Nabeel M
authors.initials: NM
authors.lastname: Elkhafif
authors.forename: Sophie
authors.initials: S
authors.lastname: Borot
authors.forename: Philippe
authors.initials: P
authors.lastname: Morel
authors.forename: Sandrine
authors.initials: S
authors.lastname: Demuylder-Mischler
authors.forename: Laurianne
authors.initials: L
authors.lastname: Giovannoni
authors.forename: Christian
authors.initials: C
authors.lastname: Toso
authors.forename: Domenico
authors.initials: D
authors.lastname: Bosco
authors.forename: Thierry
authors.initials: T
authors.lastname: Berney
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D002096:C-Peptide / Q000378:metabolism; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000601:surgery*; D005260:Female; D006801:Humans; D007328:Insulin / Q000378:metabolism; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D016381:Islets of Langerhans Transplantation; D008297:Male; D008875:Middle Aged; D016035:Pancreas Transplantation; D011384:Proinsulin / Q000378:metabolism*
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D011384:Proinsulin
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