Kidney Function after Islet Transplant Alone in Type 1 Diabetes: Impact of immunosuppressive therapy on progression of diabetic nephropathy

OBJECTIVE— Islet transplantation alone is an alternative for the replacement of pancreatic
endocrine function in patients with type 1 diabetes. The aim of our study was to assess the impact of
the Edmonton immunosuppressive protocol (tacrolimus-sirolimus association) on kidney function.
RESEARCH DESIGN AND METHODS— Nineteen patients with type 1 diabetes and
metabolic instability received islet transplantation alone and immunosuppressive therapy according
to the Edmonton protocol. Serum creatinine (sCr), creatinine clearance (CrCl), and 24-h
urinary protein excretion (UPE) were assessed at baseline and during a follow-up of 339 patientmonths.
RESULTS— After islet transplantation we observed 1) sCr within the normal range in all but
two patients in whom sCr increased immediately after islet transplantation, and despite withdrawal
of immunosuppression, patients progressed to end-stage renal disease (ESRD); 2) CrCl
remained within the normal range for those patients who had normal baseline values and
decreased, progressing to ESRD in two patients with a decreased baseline CrCl; and 3) 24-h UPE
worsened (300 mg/24 h) in four patients. In the two patients who progressed to ESRD, the
worsening of 24-h UPE occurred immediately after islet transplantation. In one patient 24-h UPE
worsening occurred at 18 months, and, after withdrawal of immunosuppression, it returned to
the normal range. In another patient 24-h UPE increased at 24 months and remained stable while
immunosuppression was continued.
CONCLUSIONS— In type 1 diabetic patients receiving islet transplantation alone, the
association of tacrolimus and sirolimus should be used only in patients with normal kidney
function. Alternative options for immunosuppressive treatment should be considered for patients
with even a mild decrease of kidney function.