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Nutrient Regulation of Amino Acid Transporters in Aging Human Skeletal Muscle

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01669590
Recruitment Status : Completed
First Posted : August 21, 2012
Last Update Posted : November 16, 2016
Information provided by (Responsible Party):
Micah Drummond, University of Utah

Brief Summary:
The goal of the research project is to determine how aging and inactivity reduce the muscle anabolic effect of nutrients and lead to muscle and functional loss. The central hypothesis is that aging reduces mTORC1 signaling and the expression of skeletal muscle amino acid transporters in response to anabolic stimulation leading to reduced muscle adaptation to increased intracellular amino acid requirements. The investigators further hypothesize that inactivity exacerbates this effect with significant muscle and functional loss, and rehabilitation restores muscle signaling, metabolism and function to baseline values.

Condition or disease

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Study Type : Observational
Actual Enrollment : 28 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Nutrient Regulation of Amino Acid Transporters in Aging Human Skeletal Muscle
Study Start Date : December 2011
Actual Primary Completion Date : September 2016
Actual Study Completion Date : September 2016

old (60-75yr)
young (18-35y)

Primary Outcome Measures :
  1. amino acid transporter [ Time Frame: before and after (1 and 3h) amino acid ingestion. These samples will be taken before bed rest and 7 days after bed rest. ]
    Muscle biopsies will be sampled from the vastus laterals before amino acid ingestion and then 1 and 3h after amino acid ingestion. Muscle biopsies will be processed using western blotting and gene expression to assess the expression of specific amino acid transporters. The investigators are interested in the change in expression of amino acid transporters in response to amino acid ingestion from baseline. The response before bed rest will be compared to after bed rest.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 75 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
young and older healthy humans

Inclusion Criteria:

1 . Age between 18-35 and 60-75 yrs 2. Ability to sign informed consent 3. Mini-mental state exam score >26 4. Free-living, prior to admission

Exclusion Criteria:

  1. Cardiac abnormalities considered exclusionary by the study physician (e.g., CHF, CAD, right-to-left shunt)
  2. Uncontrolled endocrine or metabolic disease (e.g., hypo/hyperthyroidism, diabetes)
  3. GFR <65 mL/min/1.73m2 or evidence of kidney disease or failure
  4. Vascular disease or risk factors of peripheral atherosclerosis. (e.g., uncontrolled hypertension, obesity, diabetes, hypercholesterolemia > 250 mg/dl, claudication or evidence of venous or arterial insufficiency upon palpitation of femoral, popliteal and pedal arteries)
  5. Risk of DVT including family history of thrombophilia, DVT, pulmonary emboli, myeloproliferative diseases including polycythemia (Hb>18 g/dL) or thrombocytosis (platelets>400x103/mL), and connective tissue diseases (positive lupus anticoagulant), hyperhomocysteinemia, deficiencies of factor V Leiden, proteins S and C, and antithrombin III
  6. Use of anticoagulant therapy. (e.g., Coumadin, heparin)
  7. Prior history of Heparin-Induced Thrombocytopenia (HIT)
  8. Elevated systolic pressure >150 or a diastolic blood pressure > 100
  9. Implanted electronic devices (e.g., pacemakers, electronic infusion pumps, stimulators)
  10. Cancer or history of successfully treated cancer (less than 1 year) other than basal cell carcinoma
  11. Currently on a weight-loss diet or body mass index > 30 kg/m2
  12. Inability to abstain from smoking for duration of study
  13. A history of > 20 pack per year smoking
  14. HIV or hepatitis B or C*
  15. Recent anabolic or corticosteroids use (within 3 months)
  16. Subjects with hemoglobin or hematocrit lower than accepted lab values
  17. Agitation/aggression disorder (by psychiatric history and exam)
  18. History of stroke with motor disability
  19. A recent history (<12 months) of GI bleed
  20. Pregnancy as determined by a pregnancy test
  21. Depression [>5 on the 15 items Geriatric Depression Scale (GDS)]
  22. Alcohol or drug abuse
  23. Exercise training (>1 session of moderate to high intensity aerobic or resistance exercise/week)
  24. Liver disease (AST/ALT 2 times above the normal limit, hyperbilirubinemia)
  25. Respiratory disease (acute upper respiratory infection, history of chronic lung disease with resting oxygen saturation <97% on room air)
  26. Any other condition or event considered exclusionary by the PI and faculty physician

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01669590

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United States, Utah
The University of Utah
Salt Lake City, Utah, United States, 84112
Sponsors and Collaborators
University of Utah

Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Micah Drummond, Ph.D., University of Utah Identifier: NCT01669590     History of Changes
Other Study ID Numbers: IRB_00050933
First Posted: August 21, 2012    Key Record Dates
Last Update Posted: November 16, 2016
Last Verified: November 2016

Additional relevant MeSH terms:
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Growth Substances
Physiological Effects of Drugs