Incretin Hormones in Type 1 Diabetes Mellitus;Effect of Metformin Treatment (INCREDIBLE-M)

Gut-derived Incretin Hormones in the Pathophysiology of Type 1 Diabetes Mellitus; Effect of Metformin Treatment

Investigators aim is to conduct an RCT to study the effect of adjunct metformin treatment to insulin monotherapy in patients with type 1 diabetes, targeting the intestinal incretin secretion. The patients will be randomly allocated to metformin or placebo treatment for 4 months

Compared to the large armamentarium of antidiabetic agents for Type 2 Diabetes Mellitus (T2DM), the insulinocentric therapeutic approach in Type 1 Diabetes Mellitus (T1DM) has distracted the scientific perspective from the rise of novel therapies. Insulin monotherapy has long overshadowed the overall hormonal dysregulation that demarcates T1DM . In specific, the significance of the gut-derived incretin hormones GLP-1 (glucagon-like peptide 1) and GIP (glucose-dependent insulinotropic peptide), which are implicated with glucose metabolism via the gut-pancreatic axis, has been merely addressed. Investigators' goal in the current protocol is to delineate the glucoregulatory role of incretin hormones in T1DM and the therapeutic advantages of adjunct metformin treatment over insulin monotherapy. In the absence of such knowledge, the development of effective strategies to improve metabolic homeostasis and ameliorate complications in T1DM patients will remain problematic. The central hypothesis of the study is that metformin, as an incretin-secretagogue, will enhance postprandial incretin secretion in T1DM patients, which will be reflected in reduced glucagon secretion and improvement in glycemic volatility. Mechanistic insight will be provided through changes in specific amino acids and metabolites patterns, chronic inflammation and the microbiome composition.

Pilot, mechanistic, phase 3, randomized, placebo-controlled, parallel designed, double-blinded clinical trial

All pills will be provided as effervescent, pre-scored 1000mg tablets, so that they may easily be dichotomized.Boxes with active drug or placebo will be covered to conceal the identity of the test article. Sponsor will provide covering materials.The unblinded designee will provide the covered boxes to the blinded nurse or blinded investigator who will dispense the pills.Participants will be given study drug diaries, which they will complete during study drug intake.

Patients will continue with their standard insulin therapy and will additionally receive orally metformin 2gr/day.

The primary endpoint of the study is the change in postprandial GLP-1(ng/ml) and GIP (ng/ml) secretion with metformin treatment compared to placebo.

A continuous glucose-monitoring device will be attached to each participant and record daily glucose measurements (mg/dl) for 6 consecutive days on two separate time points: a) within a week prior to randomization and b) as a follow up, within a week prior to Inpatient Visit 2.

Untargeted metabolomics analysis and identification of candidate metabolites using mass spectrometry. Quantitative targeted metabolomics will then be applied on candidate metabolites to compare differences pre and post treatment between metformin and placebo treatment arm

Corrrelation of CRP levels (mg/dl) and treatment arm, as marker of inflammation. CRP will be measured from plasma blood samples collected during Inpatient Visits 1 and 2.

Correlation of Serpin E1/PAI-1 levels (ng/ml), VEGF levels (pg/ml), ICAM1 levels (ng/ml) SYndecan-1 levels (ng/ml) and placebo/metformin administration, as markers of endothelial dysfunction. Concentration of adhesion molecules will be measured and compared from plasma blood samples collected during Inpatient Visits 1 and 2.

Correlation of TNFα levels (pg/ml) ,IL-6 levels (pg/ml),IL-1β levels (pg/ml),IL-10 levels ,(pg/ml) and placebo/metformin administration, as markers of inflammation. Concentration of cytokines will be measured and compared from plasma blood samples collected during Inpatient Visits 1 and 2.

Correlation of MMP-9 levels (ng/ml) levels and placebo/metformin administration, as markers of inflammation. Concentration of MMP-9 will be measured and compared from plasma blood samples collected during Inpatient Visits 1 and 2.

Correlation of CCL2 levels (pg/ml) ,CCL3 levels (pg/ml),CCL4 levels (pg/ml) and placebo/metformin administration, as markers of inflammation. Concentration chemokines will be measured and compared from plasma blood samples collected during Inpatient Visits 1 and 2.

RNA from PBMCs collected pre and post intervention will be isolated and Quantitative Real Time PCR will be used to measure the transcription of genes related to inflammation and endothelial function.

Stool samples will be collected pre and post the intervention on Inpatient Visits 1 and 2 to identify the changes in the microbiome composition based on phylogenetic analysis of the 16S rRNA gene sequencing classification using quantitative PCR.

Inclusion Criteria: Age ≥ 18 years T1DM (Diagnosis of diabetes before the age of 35 years and insulin use within 1 year of diagnosis) Treatment with multiple daily insulin injections (MDI) or continuous subcutaneous insulin infusion (CSII) Exclusion Criteria: Any cardiovascular disease within the last 3 months NYHA stage 3 or 4 heart failure Uncontrolled angina Liver failure [AST>135 IU/L or ALT>129IU/L (3 x the upper normal limit)] • Kidney failure or GFR<60 ml/min/1.73m2 Gastrointestinal disease or gastroparesis Prior diagnosis of cancer within 2 years Other medication that affect glucose metabolism within the last 3 months (metformin, SGLT2, GLP-1 analogues, amylin analogues, systemic glucocorticosteroids) Untreated or uncontrolled thyroid disease Pregnancy or breastfeeding Alcohol consumption > 2-drinks per day or other substance abuse