This is a prospective, clinical, monocentric study aimed to collect biological samples and study microbiota from subjects suffering from type 1 diabetes mellitus, subjects suffering from type 2 diabetes mellitus and from healthy volunteers. Microbiota is a complex consortium of microorganisms, located at the mucosal level (in particular intestinal, oral and vaginal) having a key role in human health and in the onset of several diseases. Microbiota alterations have been found in several diseases (gastrointestinal, metabolic, renal, oncological, gynaecological).

The study will allow to:

• Provide biological samples (faeces, saliva, blood, urine) from healthy volunteers and patients suffering with diabetes mellitus 1 and 2 to the first Italian microbiota biobank;
• Study microorganisms using different in vitro and in vivo techniques;
• Study the link between the microbiota and the disease. This study is part of the BIOMIS project (Project Code: ARS01_01220), presented as part of the "Avviso per la presentazione di progetti di ricerca industriale e sviluppo sperimentale nelle 12 aree di specializzazione individuate dal PNR 2015-2020" and admitted to funding under the National Operational Program "Ricerca e Innovazione" 2014-2020 by directorial decree of MIUR - Department for Higher Education and Research - n. 2298 of 12 September 2018. BIOMIS includes several clinical studies that enrol patients with different pathologies to collect and store biological samples and study microbiota.

The primary aim of this monocentric study is to populate the first national microbioma biobank with biological samples (fecal, salivary, urinary and blood samples) subjects suffering from diabetes mellitus 1 and 2, and healthy volunteers.

The secondary aim is the characterization of microorganisms of the biobank and study of the microbiota-pathology relationship using meta-omics, in vitro and in vivo approaches, The study plans to enrol 75 subjects at University of Perugia, according to the inclusion/exclusion criteria. The study participation is voluntary, and the subjects have the right to withdraw from the study at any time and for any reason.

During the study, 3 visits are planned:

• Visit 0 (V0), including description of the objectives and procedures study, signature written informed consent, inclusion/exclusion criteria evaluation, medical examination (blood pressure measurement, abdominal and thoracic physical examination), filling in of the anamnestic questionnaire, delivery of kits for the collection of fecal, salivary and urinary material to be reported at Visit 1 and delivery of a 3-day food diary, to be completed autonomously in the days preceding the Visit 1.
• Visit 1 (V1) - at least 4 days after V0, including delivery of the of the collected biological material (feces, saliva, urine), and of a 3-day food diary, filling in of the new signs and symptoms anamnestic questionnaire and blood sampling by medical staff.
• Telephone evaluation: administration of a "Food Frequency Questionnaire" to assess the subjects' alimentary habits.

Standard Operative Procedures (SOP) for samples storing, transport and processing will be adopted to ensure samples stability and grant results validity and quality.

Following collections, samples will be processed in different aliquots that will be used for:

• routine screening;
• storage in the first Italian human microbiote biobank (I.R.C.C.S. - Istituto Tumori "Giovanni Paolo II", Bari);
• evaluation of the proteomic, metascriptomic, metabolomic, metagenomic, and metagenetic profile.

Furthermore, molecular characterization of pathogenic microorganisms and pathogenic biotypes (pathovars) of commensal species of subjects with selected pathologies will be conducted.

Part of the biological material will be used for animal studies on the physiopathological role of the human intestinal microbiota transplanted into mouse models of pathology and Germ-free mouse models (specific animal study protocol developed).

The study foresees no more than minimal risk associated with blood sampling procedures. All the necessary measures to avoid any risks / inconveniences resulting from participation of the subject under study will be taken.

The study is compliant with Good Clinical Practice. Study protocol and all related documents have been approved by approved by the Independent Ethics Committees (IEC) of the involved clinical sites.

To ensure the protection and confidentiality of the participants' data, all study activities will be carried out in accordance with the European General Data Protection Regulation, Regulation (EU) 2016/679, which repeals Directive 95/46/EC.

Inclusion Criteria:

HEALTHY VOLUNTEERS

• healthy subjects aged between 18 and 60 years
• BMI between 18.5-30
• omnivorous diet
• signature of the informed consent

TYPE 1/TYPE 2 DIABETES

• subjects with type 1 diabetes aged between 18 and 50 years, type 2 diabetes aged between 18 and 65 years
• creatinine clearance > 60 mL / min
• Normoalbuminurics (ACR <30 mg / g)
• Absence of diabetic retinopathy
• DM duration <5 years
• Not being treated with metformin
• BMI between 18.5-30
• omnivorous diet
• signature of the informed consent

Exclusion Criteria:

HEALTHY VOLUNTEERS

• Current or previous infectious diseases (HAV, HBV, HCV, HIV, Cytomegalovirus, Epstein-Barr virus)
• Chronic liver disease
• History of Clostridium difficile infections
• Recent (<3 months) therapy with antibiotics, immunosuppressive drugs, chemotherapy
• Chronic therapy with proton pump inhibitors
• Recent (<3 months) use of probiotics, laxatives or other aids (drugs / supplements) for the regulation of gastrointestinal activity
• Previous history of organ / tissue transplantation
• Recent onset of diarrhea
• Chronic diarrhea
• Chronic constipation
• Previous gastrointestinal surgery (eg gastric bypass)
• Recurring urinary tract infections (3 cases per year)
• Previous major acute cardiovascular diseases (myocardial infarction, stroke)
• Type 2 diabetes mellitus
• Hypertension
• eGFR (estimated glomerular filtration rate) lower than 60ml / minute and / or diagnosis of nephropathy
• Chronic gastrointestinal disorders
• Systemic inflammatory diseases
• Suspicion, clinical diagnosis or previous history of cancer (<5 years)
• Autoimmune disorders or history of chronic and systemic autoimmune disorders
• Neurodegenerative disorders
• Pregnancy and breastfeeding
• Healthcare workers
• Operators work with animals
• Psychiatric conditions that reduce protocol compliance.

TYPE 1/TYPE 2 DIABETES

• Current or previous infectious diseases (HAV, HBV, HCV, HIV, Cytomegalovirus, Epstein-Barr virus)
• Chronic liver disease
• History of Clostridium difficile infections
• Recent (<3 months) therapy with antibiotics, immunosuppressive drugs, chemotherapy
• Chronic therapy with proton pump inhibitors
• Recent (<3 months) use of probiotics, laxatives or other aids (drugs / supplements) for the regulation of gastrointestinal activity
• Previous history of organ / tissue transplantation
• Recent emergence of diarrhea
• Chronic diarrhea
• Chronic constipation
• Previous gastrointestinal surgery (eg gastric bypass)
• Recurring urinary tract infections (3 cases per year)
• Previous major acute cardiovascular diseases (myocardial infarction, stroke) occurred in the last 3 years
• Chronic gastrointestinal disorders
• Systemic inflammatory diseases
• Suspicion, clinical diagnosis or previous history of cancer (<5 years)
• Autoimmune disorders or history of chronic and systemic autoimmune disorders
• Neurodegenerative disorders
• Pregnancy and breastfeeding
• Psychiatric conditions that reduce protocol compliance.

Patients with type 1 and 2 diabetes attending the clinical centres involved in the study.

Healthy volunteers will be recruited by invitation. Enrolled subjects must not have any family relationship and hierarchical subordination with the hospitals in which biological samples will be collected.