Cross-sectional and prospective association between proinsulin secretion and graft function after clinical islet transplantation.
Proinsulin levels as a marker of beta-cell dysfunction have not been described after clinical islet transplantation. Proinsulin secretion was studied in 23 type 1 diabetic patients after islet allotransplantation and in 20 age-matched nondiabetic controls. Fasting serum insulin, total proinsulin (TP), intact proinsulin, proinsulin fragments (PFs) and their ratios to insulin were determined 1 and 12 months after patients became insulin independent. TP, PF, and proinsulin/insulin ratios were lower in transplant recipients compared with controls, in patients who retained long-term insulin independence. Insulin, C-peptide, and intact proinsulin values were similar in transplant recipients and controls. Hormone levels remained stable over time in the group of patients who retained long-term insulin independence, but the TP and PF levels were higher at 12 months compared with 1 month in the group of patients who resumed insulin therapy. TP and PF levels were reduced in transplant recipients compared with controls but increased over time if insulin independence was lost.
McDonald
Charlotte G
CG
Clinical Islet Transplant Program, University of Alberta, Edmonton, Alberta, Canada.
Ryan
Edmond A
EA
Paty
Breay W
BW
Senior
Peter A
PA
Marshall
Sally M
SM
Lakey
Jonathan R T
JR
Shapiro
A M James
AM
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D002096:C-Peptide / Q000097:blood; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000601:surgery*; D005215:Fasting; D006085:Graft Survival / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000097:blood; D016381:Islets of Langerhans Transplantation / Q000502:physiology*; D011384:Proinsulin / Q000097:blood / Q000378:metabolism*; D012016:Reference Values; D013997:Time Factors
D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D011384:Proinsulin