Patients with type 1 diabetes are eligible for this study. Major criteria for inclusion are: age 18-65 years; type 1 diabetes with onset <40 years of age; insulin treatment of at least 5 years at the time of enrollment; stimulated C-peptide in response to arginine <0.5 ng/ml; multiple (three or more) daily insulin injections or Continuous Subcutaneous Insulin Infusion; self-blood glucose monitoring ≥3 times/day; high glycemic instability and/or hypoglycemia unawareness; inability to consistently attain a glycated hemoglobin target of <7.5 % without severe hypoglycemia (defined as an hypoglycemic episode requiring the assistance by another person for its resolution) in the past 36 months despite medical management by a diabetes specialist. Major criteria for exclusion are: HbA1c >12%; BMI >30 kg/m2, or insulin requirement > 0.8 IU/kg/day; poorly controlled hypertension; untreated proliferative diabetic retinopathy; presence or history of macroalbuminuria (>300mg/g day) or estimated glomerular filtration rate <60 ml/min/1.73 m2 for females or <70 ml/min/1.73 m2 for males.