Simple measures to monitor β-cell mass and assess islet graft dysfunction

R. N. Faradji, K. Monroy, S. Messinger, A. Pileggi, T. Froud, D. A. Baidal, P. E. Cure, C. Ricordi, L. Luzi, R. Alejandro

Research output: Contribution to journalArticlepeer-review

67 Scopus citations

Abstract

The aim of this study was to develop a simple test for the assessment of islet graft dysfunction based on measures involving fasting C-peptide. Calculations were made to account for the dependence of C-peptide secretion on glucose concentration (C-peptide/glucose ratio [CP/G]) and adjusted for renal function by calculating the C-peptide/glucose-creatinine ratio (CP/GCr). Values from 22 recipients were analyzed at different times post-last islet infusion. Receiver operating characteristic curves were used to determine which of these measures best predicts high 90-minute glucose (90 min-Glc; >10 mmol/L) after a Mixed Meal Tolerance Test (MMTT). In this initial analysis, CP/G was found to be superior predicting high 90 min-Glc with a larger area under the ROC curve than C-peptide (p = 0.01) and CP/GCr (p = 0.06). We then correlated C-peptide and CP/G with islet equivalents-IEQ/kg infused, 90 min-Glc after MMTT and clinical outcome (β-score). C-peptide and CP/G in the first 3 months post-last islet infusion correlated with IEQ/kg infused. CP/G correlated with 90 min-Glc and β-score. C-peptide and CP/G are good indicators of islet mass transplanted. CP/G is more indicative of graft dysfunction and clinical outcome than C-peptide alone. The ease of calculation and the good correlation with other tests makes this ratio a practical tool when monitoring and managing islet transplant recipients.

Original languageEnglish (US)
Pages (from-to)303-308
Number of pages6
JournalAmerican Journal of Transplantation
Volume7
Issue number2
DOIs
StatePublished - Feb 2007

Keywords

  • β-cell mass
  • C-peptide
  • Graft dysfunction
  • Insulin independence
  • Islet transplantation

ASJC Scopus subject areas

  • Immunology

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