Beta cell function during rapamycin monotherapy in long-term type 1 diabetes.
OBJECTIVE
Type 1 diabetes is considered non-reversible at end-stage disease when there is no measurable insulin production. However, there are indications that insulin-producing beta cells could be present or return if autoimmunity could be controlled. We therefore sought to determine whether immunosuppression therapy can reinstate beta cell function in patients with long-term type 1 diabetes.


METHODS
We examined pancreatic beta cell function in 22 patients with long-term type 1 diabetes (median disease duration 27 years), who had been receiving rapamycin monotherapy (0.1 mg/kg; target trough levels 8-10 ng/ml; 26-314 days) as pre-conditioning for islet transplantation. As control, beta cell function was measured in 14 patients (median disease duration 17 years) who were waiting for an islet transplant without rapamycin pre-conditioning.


RESULTS
Fasting C-peptide increased from <0.03 nmol/l (0.0066 nmol/l, interquartile range [IQR] 0.0003-0.023) at baseline to 0.039 nmol/l (IQR 0.0066-0.096) at end of rapamycin monotherapy (p < 0.005). In 12 patients, fasting C-peptide increased to >0.076 nmol/l (C-peptide responders). Exogenous insulin requirement decreased from 0.64 U/kg daily (IQR 0.56-0.72) to 0.57 U/kg (IQR 0.45-0.70; p = 0.01), but this reduction was significant only in the 12C-peptide-responsive patients. Rapamycin monotherapy was also associated with a decrease in insulin antibody titre (median decrease 110 to 35.9 U/ml; p < 0.001) and fasting serum proinsulin (median decrease 0.51 to 0.28 pmol/l; p = 0.001). All variables remained unchanged in the 14 control patients.


CONCLUSIONS
Therapies to reinstate beta cell function may be applicable to patients with long-term C-peptide-negative type 1 diabetes.


BACKGROUND
ClinicalTrial.gov NCT01060605.
Diabetes Research Institute (HSR-DRI), San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy. piemonti.lorenzo@hsr.it
L
L
Piemonti
P
P
Maffi
L
L
Monti
V
V
Lampasona
G
G
Perseghin
P
P
Magistretti
A
A
Secchi
E
E
Bonifacio
D000328:Adult; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D050417:Insulin-Secreting Cells / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011384:Proinsulin / Q000097:blood; D020123:Sirolimus / Q000627:therapeutic use*
D007166:Immunosuppressive Agents; D011384:Proinsulin; D020123:Sirolimus