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Metformin Improves Insulin Sensitivity and Vascular Health in Youth With Type 1 Diabetes Mellitus.

ABSTRACT: BACKGROUND:Cardiovascular disease is the leading cause of mortality in type 1 diabetes mellitus (T1DM) and relates strongly to insulin resistance (IR). Lean and obese adolescents with T1DM have marked IR. Metformin improves surrogate markers of IR in T1DM, but its effect on directly measured IR and vascular health in youth with T1DM is unclear. We hypothesized that adolescents with T1DM have impaired vascular function and that metformin improves this IR and vascular dysfunction. METHODS:Adolescents with T1DM and control participants underwent magnetic resonance imaging of the ascending (AA) and descending aorta to assess pulse wave velocity, relative area change, and maximal (WSSMAX) and time-averaged (WSSTA) wall shear stress. Participants with T1DM also underwent assessment of carotid intima-media thickness by ultrasound, brachial distensibility by DynaPulse, fat and lean mass by dual-energy x-ray absorptiometry, fasting laboratories after overnight glycemic control, and insulin sensitivity by hyperinsulinemic-euglycemic clamp (glucose infusion rate/insulin). Adolescents with T1DM were randomized 1:1 to 3 months of 2000 mg metformin or placebo daily, after which baseline measures were repeated. RESULTS:Forty-eight adolescents with T1DM who were 12 to 21 years of age (40% body mass index [BMI] ?90th percentile; 56% female) and 24 nondiabetic control participants of similar age, BMI, and sex distribution were enrolled. Adolescents with T1DM demonstrated impaired aortic health compared with control participants, including elevated AA and descending aorta pulse wave velocity, reduced AA and descending aorta relative area change, and elevated AA and descending aorta WSSMAX and WSSTA. Adolescents with T1DM in the metformin versus placebo group had improved glucose infusion rate/insulin (12.2±3.2 [mg·kg-1·min-1]/?IU/?L versus -2.4±3.6 [mg·kg-1·min-1]/?IU/?L, P=0.005; 18.6±4.8 [mg·lean kg-1·min-1]/?IU/?L versus -3.4±5.6 [mg·lean kg-1·min-1]/?IU/?L, P=0.005) and reduced weight (-0.5±0.5 kg versus 1.6±0.5 kg; P=0.004), BMI (-0.2±0.15 kg/m2 versus 0.4±0.15 kg/m2; P=0.005), and fat mass (-0.7±0.3 kg versus 0.6±0.4 kg; P=0.01). Glucose infusion rate/insulin also improved in normal-weight participants (11.8±4.4 [mg·kg-1·min-1]/?IU/?L versus -4.5±4.4 [mg·kg-1·min-1]/?IU/?L, P=0.02; 17.6±6.7 [mg·lean kg-1·min-1]/?IU/?L versus -7.0±6.7 [mg·lean kg-1·min-1]/?IU/?L, P=0.02). The metformin group had reduced AA WSSMAX (-0.3±0.4 dyne/cm2 versus 1.5±0.5 dyne/cm2; P=0.03), AA pulse wave velocity (-1.1±1.20 m/s versus 4.1±1.6 m/s; P=0.04), and far-wall diastolic carotid intima-media thickness (-0.04±0.01 mm versus -0.00±0.01 mm; P=0.049) versus placebo. CONCLUSIONS:Adolescents with T1DM demonstrate IR and impaired vascular health compared with control participants. Metformin improves IR, regardless of baseline BMI, and BMI, weight, fat mass, insulin dose, and aortic and carotid health in adolescents with T1DM. Metformin may hold promise as a cardioprotective intervention in T1DM. CLINICAL TRIAL REGISTRATION:URL: https://www.clinicaltrials.gov . Unique identifier: NCT01808690.

SUBMITTER: Bjornstad P

PROVIDER: S-EPMC6428045 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature

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Metformin Improves Insulin Sensitivity and Vascular Health in Youth With Type 1 Diabetes Mellitus.

Bjornstad Petter P Schäfer Michal M Truong Uyen U Cree-Green Melanie M Pyle Laura L Baumgartner Amy A Garcia Reyes Yesenia Y Maniatis Aristides A Nayak Sunil S Wadwa R Paul RP Browne Lorna P LP Reusch Jane E B JEB Nadeau Kristen J KJ

Circulation 20181201 25

<h4>Background</h4>Cardiovascular disease is the leading cause of mortality in type 1 diabetes mellitus (T1DM) and relates strongly to insulin resistance (IR). Lean and obese adolescents with T1DM have marked IR. Metformin improves surrogate markers of IR in T1DM, but its effect on directly measured IR and vascular health in youth with T1DM is unclear. We hypothesized that adolescents with T1DM have impaired vascular function and that metformin improves this IR and vascular dysfunction.<h4>Metho ...[more]

PMID: 30566007

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Project description:Metformin, a commonly used drug prescribed to treat type-2 diabetes, has been found to extend health span and delay cancer incidence and progression. Here, we report that starting chronic treatment with low dose of metformin (0.1% w/w in diet) at one year of age extends health and lifespan in male mice, while a higher dose (1% w/w) was toxic. Treatment with low dose metformin mimicked some of the benefits of calorie restriction, such as improved physical performance, increased insulin sensitivity, and reduced LDL and cholesterol levels. At a molecular level, metformin increased AMP-activated protein kinase activity without attenuation of the mitochondrial electron transport chain activities. Metformin treatment resulted in lower chronic inflammation and increased antioxidant protection, suggesting that the ability of metformin to improve health of laboratory animals may stem from these factors. Our results support that metformin supplementation could be beneficial in extending health and lifespan in humans. Groups of one-year old male B6C57/J mice were maintained on ad libitum AIN-93G SD diet, or a 40% caloric restriction of the AIN-93G SD diet, or an ad libitum AIN-93G diet supplemented with 0.1% w/w metformin for the rest of their lives. 5 mice from each of these 3 groups were selected and RNA was extracted from both muscle and liver tissue using 1.0mm glass beads in a Precellys 24 Tissue Homogenizer and Qiagen RNeasy Mini Kits for Fibrous Tissue according to manufacturer's specifications. Quality and quantity of the total RNA was checked with the Agilent 2100 bioanalyzer using RNA 6000 Nano chips. RNA samples were labeled using the Illumina TotalPrep RNA Amplification Kit. In short, 0.5g of total RNA was first converted into single-stranded cDNA with reverse transcriptase using an oligo-dT primer containing the T7 RNA polymerase promoter site and then copied to produce double-stranded cDNA molecules. The double stranded cDNA was cleaned and concentrated with the supplied columns and used in an overnight in-vitro transcription reaction where single-stranded RNA (cRNA) was generated and labeled by incorporation of biotin-16-UTP. Arrays were hybridized using a total of 0.75ug of biotin-labeled cRNA at 58 degrees C for 16 hours to Illumina's Sentrix MouseRef-8 v2 Expression BeadChips. Each BeadChip has ~24,000 well-annotated RefSeq transcripts with approximately 30-fold redundancy. The arrays were washed, blocked and the biotin labeled cRNA was detected by staining with streptavidin-Cy3. Arrays were scanned at a resolution of 0.8um using the Beadstation 500 X from Illumina and the data was extracted using the Illumina GenomeStudio software(v1.6.0). Any spots at or below the background were filtered out using an Illumina detection p value of 0.02 and above. The natural log of all remaining scores were used to find the avg and std of each array and the z-score normalization was calculated and presented below. Z-score = (raw value - avg)/std.

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Metformin Improves Insulin Sensitivity and Vascular Health in Youth With Type 1 Diabetes Mellitus.

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Metformin Improves Insulin Sensitivity and Vascular Health in Youth With Type 1 Diabetes Mellitus.

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