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  • Metformin Effect on Brain Function in Insulin Resistant Elderly People Rochester, Minn.

    The purpose of this study is to determine whether 40 weeks of metformin administration in elderly people (> 60 years) with insulin resistance enhances brain mitochondrial ATP production, to determine the effect of 40 weeks of metformin administration in elderly people (> 60 years) with insulin resistance on blood flow and functional network in different areas of brain, and to determine the effect of 40 weeks of metformin administration in elderly people (> 60 years) with insulin resistance on cognitive function.

  • Molecular Mechanisms of Acute Effects of Resistance Exercise - Pilot Study Rochester, Minn.

    The purpose of this study is to seek and identify the mechanistic underpinnings of the effects of resistance exercise (RE) on insulin sensitivity.

Closed for Enrollment

  • Effect of acute exercise on secreted biomarkers Rochester, Minn.

    Muscle proteins accumulate damage during aging and leads to the loss of muscle mass and function in older people. Exercise can increase the making of new proteins and removal of older proteins, but it is not known if the effect changes with aging or type of exercise. The investigators will determine the ability for endurance, resistance, or a combination of exercise training to remove older-damaged proteins and make newer-functional muscle proteins in groups of younger and older people. The investigators will particularly study protein that are involved with energy production (mitochondrial proteins) and force production (contractile proteins).

    Hypothesis 1: Older people will have greater accumulation of damaged proteins than younger people.

    Hypothesis 2: Aerobic exercise will decrease the accumulation of damaged forms of contractile and mitochondrial proteins in younger and older people.

    Hypothesis 3: Resistance exercise will decrease the accumulation of damaged forms of contractile proteins in younger and older people.

  • Effect of High Fat and High Glycemic Diets on Muscle Protein Synthesis in Somali Immigrants and Americans of Northern European Descent Rochester, Minn.

    The investigators will determine whether people with high muscle mitochondrial capacity produce higher amount of reactive oxygen species (ROS) on consuming high fat /high glycemic diet and thus exhibit elevated cellular oxidative damage. The investigators previously found that Asian Indian immigrants have high mitochondrial capacity in spite of severe insulin resistance. Somalians are another new immigrant population with rapidly increasing prevalence of diabetes. Both of these groups traditionally consume low caloric density diets, and the investigators hypothesize that when these groups are exposed to high-calorie Western diets, they exhibit increased oxidative stress, oxidative damage, and insulin resistance. The investigators will compare Somalians and NE Americans who are matched for age, BMI, and sex. The investigators will measure ROS production in skeletal muscle following high fat/high glycemic diet vs. healthy diet. The investigators will compare the oxidative damage to proteins, DNA, and lipids in these two populations following 10 days of high fat/high glycemic index diet in comparison with low fat diet. The investigators will determine if elevated levels of oxidative damage in Somali immigrant populations is accompanied by high mitochondrial capacity, higher ROS-emitting potential, and lower insulin sensitivity than NE. The proposed study will be performed utilizing the state-of-the-art proteomic and metabolomic methods many of which were recently developed in our laboratory. The investigators expect the results from this study to provide seminal insights into the underlying mechanism of insulin resistance and type 2 diabetes, in addition to demonstrating mechanisms by which a functional proteome is maintained in vivo.

  • In Vivo Assessment of the Tricarboxylic Acid Cycle Flux in the Muscle and Splanchnic Bed of Humans: A Pilot Study Rochester, Minn.

    The purpose of this study is to establish an arterial/venous method to measure the activity of the Tricarboxylic Acid or cell metabolism cycle directly in the tissues of human beings. There will also be correlative studies on the proteome, metabolome, oxygen consumption, carbon dioxide production and exosomes related to TCA cycle activity.

  • Metformin's Effect on Glucagon-induced Endogenous Glucose Production, Protein Metabolism and Resting Energy Expenditure in Insulin Resistant Individuals. Rochester, Minn.

    This study is being done to understand metformin's mechanisms of action regarding glucose production, protein metabolism, and mitochondrial function.

  • Molecular Mechanisms of Exercise Benefits to Insulin Resistant People Rochester, Minn.

    The purpose of this study is to seek and identify the mechanistic underpinnings of the effects of resistance exercise (RE), especially on insulin sensitivity, oxidative stress, and muscle hypertrophy and strength, in pre-diabetic people with abdominal obesity and insulin resistance (IR).

  • Pilot Study to Evaluate the Effects of Insulin Deprivation on Brain Structure and Function in Humans With Type 1 Diabetes Rochester, Minn.

    What are the effects of transient insulin deprivation on brain structure, blood flow, mitochondrial function, and cognitive function in T1DM patients? What are the effects of transient insulin deprivation on circulating exosomes and metabolites in T1DM patients?

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