Human Intestinal Peptides Evaluation and Research

For NON-SURGERY GROUPS Inclusion Criteria: 1. GROUP NS-A: Healthy participants, no known disease, no previous surgery, HbA1c\<5.7%, BMI\<25 kg/m2 (n=30). GROUP NS-B: Obese diabetic, type 2 diabetes diagnosis longer than 3 years; BMI\>30 kg/m2 (n=30). GROUP NS-C: Non-obese diabetic, type 2 diabetes diagnosis longer than 3 years; BMI\<30 kg/m2 (n=30). GROUP NS-D: Obese non-diabetics, HbA1c\<5.7%, No signs and history of T2D, and BMI\>30 kg/m2 (n=30). 2. Preferably not on any kind of anti-diabetic drugs or will accept cessation of all anti-diabetic drugs 2 days prior to evaluation. 3. Absence of co-morbidities (dyslipidemia, hypertension, neuropathy, retinopathy, cardiovascular disease, stroke events or lower extremity amputation). 4. Possibility to participate to the quadruplicate measurement protocol. Exclusion Criteria: 1. Anti insulin / islet antibody and glutamic acid decarboxylase antibody (antiGAD) positivity, plasma fasting C-peptide lesser than 1 ng/ml. 2. Liver cirrhosis, severe renal failure, collagen diseases, severe endocrinopathies, blindness. 3. Heart failure, acute myocardial infarction, stroke or transient ischemic attack, unstable angina pectoris. 4. History of malignancy or malignant neoplasm in place, severe inflammatory complications, neurological or cardiovascular in act. 5. Pregnancy 6. Any conditions that at the discretion of the head of the study can represent risk to the participant or could affect the protocol results. For SURGERY GROUPS Inclusion Criteria: 1. Type 2 Diabetic participants who underwent a sleeve gastrectomy, a mini-gastric bypass, a sleeve gastrectomy with ileal transposition or a sleeve gastrectomy with transit bipartition performed more than 6 months ago, but within the last 2 years, with steady weight profile. 2. Preferably not on any kind of anti-diabetic drugs or will accept cessation of all anti-diabetic drugs 2 days prior to evaluation. 3. Absence of or resolved co-morbidities (dyslipidemia, hypertension, neuropathy, retinopathy, cardiovascular disease, stroke events or lower extremity amputation). 4. Possibility to participate to the quadruplicate measurement protocol. Exclusion Criteria: 1. Liver cirrhosis, severe renal failure, collagen diseases, severe endocrinopathies, blindness. 2. Heart failure, acute myocardial infarction, stroke or transient ischemic attack, unstable angina pectoris. 3. History of malignancy or malignant neoplasm in place, severe inflammatory complications, neurological or cardiovascular in act. 4. Pregnancy 5. Any conditions that at the discretion of the head of the study can represent risk to the participant or could affect the protocol results.