Immune Cells During Disuse and Recovery

Study Overview
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Brief Summary
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This is an interventional study enrolling healthy individuals aged 18-35 and 60-85 to understand the recovery of muscle health following a period of inactivity. The enrollment goal is 45 participants. The study will occur over the course of 1-2 months where participants will undergo testing before and after a 2-week limb immobilization period.

Detailed Description
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Visit 1 (Pre-testing)- After signing a consent form, participants will undergo a blood screening and an oral glucose tolerance test. After the visit, participants will be provided with a step activity monitor to track their level of activity. A dietary assessment will also be determined. Visit 2- At a later time, the participant will return to the research center for a biopsy, blood draw, body composition scan, MRI and muscle strength testing. 2-week leg immobilization period- After visit 2 , the participant will return home and undergo a 14-day leg immobilization period using the equipment and instructions provided at visit 2. Visit 3- During the limb immobilization period, participant will return to the research center for a single blood draw. Visit 4- At the end of the 2-week limb immobilization period, the participant will return to the research center to undergo another biopsy, blood draw, body composition scan, MRI and muscle strength testing. Visit 5- 2 days after the 2-week limb immobilization period, the participant will return for a biopsy and blood draw. Visit 6- 7 days after the 2-week limb immobilization period, the participant will be asked to return for a final biopsy, blood draw, body composition scan, MRI and muscle strength testing.

Official Title
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Muscle Immune Cells During Disuse and Recovery in Aging and Metabolic Disease

Conditions
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Muscle Disuse

Intervention / Treatment
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* Other: Limb immobilization


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 18-35 and 60-85 yrs Ability to sign informed consent Free-living, prior to admission Exclusion Criteria: History of cardiovascular disease (e.g., CHF, CAD, right-to-left shunt) History of endocrine or metabolic disease such as hypo/hyperthyroidism and diabetes History of kidney disease or failure Vascular disease 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), hyperhomocystinemia, deficiencies of factor V Leiden, proteins S and C, and antithrombine III Use of anticoagulant therapy (e.g., Coumadin, heparin) Elevated systolic pressure >150 or a diastolic blood pressure > 100 Implanted electronic devices (e.g., pacemakers, electronic infusion pumps, stimulators) Cancer or history of successfully treated cancer (less than 1 year) other than basal cell carcinoma Currently on a weight-loss diet Chronic systemic corticosteroid use (≥ 2 weeks) within 4 weeks of enrollment and for study duration (intra-articular/topical/inhaled therapeutic or physiologic doses of corticosteroids are permitted) Androgens or growth hormone within 6 months of enrollment and for study duration (topical physiologic androgen replacement is permitted) History of stroke with motor disability A recent history (<12 months) of GI bleed History of liver disease History of respiratory disease (acute upper respiratory infection, history of chronic lung disease) Pregnancy as determined by a pregnancy test Any staff members who report directly to an investigator or who report to someone who reports directly to an investigator. Any other condition or event considered exclusionary by the PI and faculty physician

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Interventional Model Description: Participants will be tested before a 2-week limb immobilization period
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Limb immobilization<br>Participants will undergo a 2-week leg immobilization period | Other: Limb immobilization<br>* Participants will undergo a 2-week period of leg immobilization<br>* Other names: Muscle Disuse;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Thigh Muscle Volume | change in thigh muscle volume as determined by MRI | baseline and after 2 weeks of leg immobilization | 
| Leg Muscle Strength | change in isometric leg extension strength as determined by a isokinetic dynamometer | baseline and after 2 weeks of leg immobilization |