The purpose of the study is to identify new biomarkers of Adult Onset Autoimmune Diabetes (AOnAD).

Inclusion Criteria:

Type 1 Diabetes (T1D)

• age 18-35 years
• age at diagnosis 13 to 30 years
• Body Mass Index (BMI) 25 to 35 kg/m2 with a stable body weight (±3 kg in the past 6 months)
• diagnosis of T1D according to American Diabetes Association (ADA) criteria continuously requiring insulin for survival (if in doubt, diagnosis can be confirmed by positivity of 2 or more IAAb* at time of diagnosis, at any time or at time of recruitment)
• diabetes diagnosis performed within the previous 5 years,
• requiring insulin continuously since diagnosis to prevent ketosis
• Fasting C-peptide levels < 0.3 nmol/l

Type 2 Diabetes (T2D)

• age 40-75 years
• age at diagnosis 40 to 70 years
• BMI 25 to 35 kg/m2 with a stable body weight (±3 kg in the past 6 months)
• diagnosis of diabetes according to ADA criteria
• Diabetes diagnosis performed within the previous 5 years
• Not requiring insulin
• Fasting C-peptide levels > 0.3 nmol/l

Adult Onset Autoimmune Diabetes/Latent Autoimmune Diabetes of Adults (AOnAD/LADA)

• age 40-75 years
• age at diagnosis 40 to 70 years
• BMI 25 to 35 kg/m2 with a stable body weight (±3 kg in the past 6 months)
• diagnosis of diabetes according to ADA criteria
• fasting C-peptide > 0.3 nmol/l
• positive for at least one islet autoantibody (IAAb* - at time of diagnosis, at any time or at time of recruitment)
• not requiring insulin or, if on insulin, treatment started at least 6 months after diagnosis

Healthy Normal Volunteers (HNV)

• age 40-75 years

• BMI 25 to 35 kg/m2 with a stable body weight (±3 kg in the past 6 months)

• No personal history of diabetes according to ADA criteria

• No history of diabetes in first degree relatives (FDRs)

• Fasting C-peptide levels > 0.3 nmol/l

  • IAAbs are Insulin AutoAntibodies (IAA), Thyrosine phosphatase IA-2 Antibodies (IA-2 Ab), Glutamic Acid Decarboxylase Antibodies (GAD Ab), Zinc Transporter 8 Antibodies (ZnT8 Ab), Islet Cell Antibodies (ICA).

Exclusion Criteria:

• For T2D participants: treatment with insulin or with thiazolidinediones (TZDs).
• For T1D and AOnAD/LADA participants: treatment with TZDs.
• Presence of unstable cardiovascular disease (unstable angina, myocardial infarction or coronary revascularization within 6 months, clinically significant abnormalities on EKG, presence of cardiac pacemaker, implanted cardiac defibrillator)
• Evidence of acute or chronic liver disease even if asymptomatic (AST or ALT >2.5 times the upper limit of normal)
• Kidney disease (creatinine >1.6 mg/dl or estimated GFR<60 ml/min)
• Triglycerides >500 mg/dl, LDL >200 mg/dl
• Uncontrolled hypertension (Blood Pressure BP>160 mmHg systolic or >100 mmHg diastolic)
• Recent important weight loss (>3 kg in 3 months)
• History of drug or alcohol abuse (> 3 drinks per day) within the last 5 years.
• History of cancer within the last 5 years (skin cancers, with the exception of melanoma, may be acceptable).
• History of organ transplant.
• History of bariatric surgery
• Bleeding or coagulation disorders requiring chronic use of blood thinners.
• Current treatment with blood thinners or antiplatelet medications that cannot be safely stopped for study procedures
• History of chronic pancreatitis or pancreatic surgery
• Acute or chronic infections
• History of HIV, active Hepatitis B or C, or Tuberculosis.
• Anemia (hemoglobin <12 g/dl in men, <11 g/dl in women) or other chronic hematology disorders.
• Use of any medications known to influence glucose, fat and/or energy metabolism within the last 3 months (e.g., growth hormone therapy, glucocorticoids [steroids], etc.) other than the treatment for diabetes
• Thyroid dysfunction. Participants with a Thyroid Stimulating Hormone TSH > 10 µ IU or less than 0.4 µ IU are excluded. Participants on thyroid replacement medication or on antithyroid drugs may be enrolled providing they have been on a stable dose of medication for at least 6 weeks prior to screening and their TSH is within the range specified above.
• Severe asthma or chronic obstructive pulmonary disease
• Initiation or change in hormone replacement therapy within the past 3 months (including, but not limited to birth control or estrogen replacement therapy)
• Cushing's disease or syndrome
• Drugs that affect immune, weight or metabolic function, including but not limited to: oral corticosteroids, oral or injectable anti-obesity medications. Drugs for dyslipidemia (statins, ezetimibe, etc.) and a daily full strength or baby aspirin for atherosclerosis prevention will be allowed, provided patients have been on stable doses for at least 6 weeks prior to screening and that aspirin could be safely temporarily stopped for the study
• Weight >450 lbs. (This is Dual X-ray Absorptiometry (DEXA) table weight limit)
• Gastrointestinal disorders associated with malabsorption.
• Pregnant or nursing females or females less than 6 months postpartum from the scheduled date of collection.
• Had major surgery within 4 weeks prior to the pre-trial (screening) visit
• Participation in studies involving investigational drug(s) within 30 days prior to Screening Visit 1
• Blood donation (excluding plasma donations) of approximately 1 pint (500 mL) or more within 56 days prior to Screening Visit
• Allergies to milk derived or soy derived products, lactose intolerance (due to the composition of the standard liquid meal that will be used for the test)
• Allergies and reactions to lidocaine.
• History of eating disorders
• Psychiatric disease prohibiting adherence to study protocol
• Unable to provide a reliable informed consent
• Presence of any condition that, in the opinion of the investigator and clinical team, compromises participant safety or data integrity or the participant's ability to complete study visits

This is an observational cross-sectional pilot study that will compare 4 groups of 10 participants each (5±1 of each gender per group) affected by AOnAD, T2D, T1D and Healthy Normal Volunteers (HNV). They will be characterized clinically and biochemically.