Three-way, Cross-over Closed-loop Exercise Study

Inclusion Criteria

• Diagnosis of type 1 diabetes mellitus for at least 1 year.
• Male or female subjects 21 to 45 years of age.
• Physically willing and able to perform 45 min of exercise (as determined by the investigator after reviewing the subjects activity level)
• Current use of an insulin pump.
• Willingness to follow all study procedures, including attending all clinic visits.
• Willingness to sign informed consent and HIPAA documents.

Exclusion Criteria

• Female of childbearing potential who is pregnant or intending to become pregnant or breast-feeding, or is not using adequate contraceptive methods. Acceptable contraception includes birth control pill / patch / vaginal ring, Depo-Provera, Norplant, an IUD, the double barrier method (the woman uses a diaphragm and spermicide and the man uses a condom), or abstinence.
• Any cardiovascular disease, defined as a clinically significant EKG abnormality at the time of screening or any history of: stroke, heart failure, myocardial infarction, angina pectoris, or coronary arterial bypass graft or angioplasty. Diagnosis of 2nd or 3rd degree heart block or any non-physiological arrhythmia judged by the investigator to be exclusionary.
• Renal insufficiency (GFR < 60 ml/min, using the MDRD equation as report by the OHSU laboratory).
• Impaired liver function, defined as AST or ALT ≥2.5 times upper limit of normal, according to OHSU laboratory reference ranges.
• Hematocrit of less than or equal to 34%.
• History of severe hypoglycemia during the past 12 months prior to screening visit or hypoglycemia unawareness as judged by the investigator.
• Adrenal insufficiency.
• Any active infection.
• Known or suspected abuse of alcohol, narcotics, or illicit drugs.
• Seizure disorder.
• Active foot ulceration.
• Severe peripheral arterial disease characterized by ischemic rest pain or severe claudication.
• Major surgical operation within 30 days prior to screening.
• Use of an investigational drug within 30 days prior to screening.
• Chronic usage of any immunosuppressive medication (such as cyclosporine, azathioprine, sirolimus, or tacrolimus).
• Bleeding disorder, treatment with warfarin, or platelet count below 50,000.
• Allergy to aspart insulin.
• Allergy to glucagon.
• Insulin resistance requiring more than 200 units per day.
• Need for uninterrupted treatment of acetaminophen.
• Current administration of oral or parenteral corticosteroids.
• Any life threatening disease, including malignant neoplasms and medical history of malignant neoplasms within the past 5 years prior to screening (except basal and squamous cell skin cancer).
• C peptide level of ≥0.5 ng/ml
• Any concurrent illness, other than diabetes, that is not controlled by a stable therapeutic regimen.
• Beta blockers or non-dihydropyridine calcium channel blockers.
• A positive response to any of the questions from the Physical Activity Readiness Questionnaire.
• Any clinically significant disease or disorder which in the opinion of the Investigator may jeopardize the subject's safety or compliance with the protocol.