Blood Flow, Muscle Regeneration and Sarcopenia

Completed

Conditions: Sarcopenia

Registration Number: NCT01035060

Lead Sponsor: University of Florida

Brief Summary: Due to the rapid aging of the population, sarcopenia is among the greatest challenges facing the health care system over the next quarter century. This age-related loss of skeletal muscle mass and strength directly contributes to the incidence of functional disability, thereby reducing independence and quality of life for the elderly. Despite increasing efforts to combat sarcopenia, its etiology remains incompletely described. Subsequently, limited progress has been made in developing comprehensive preventative and therapeutic strategies to combat the problem. A decreased ability to regenerate skeletal muscle fibers through the donation of skeletal muscle stem cells (satellite cells) is thought to contribute to sarcopenia. However, the upstream physiological mediators that regulate this impairment are poorly delineated.

Reduced muscle blood flow in advanced age appears to be a significant factor in reducing skeletal muscle regenerative capacity, but few data exist to confirm this hypothesis. Thus to test this hypothesis we aim to conduct a translational pilot trial which examines regeneration in both young and old adults. Furthermore, we aim to determine if muscle blood flow and satellite cell number are associated with muscle function. The central hypothesis of this proposal is that age-related declines in skeletal muscle angiogenesis and perfusion are significant causal factors in age-related losses of skeletal muscle mass. The specific aims and hypotheses of the project are as follows:

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 68

Inclusion Criteria

Men and women aged 18-30 years
Men and women aged > 70 years
Body mass index < 35
Willing and able to participate in all aspects of the study
Sedentary to moderately active lifestyle <120 min physical activity/week < 30 min moderate aerobic exercise/week < 30 min resistance training/week OR Participates in regular structured exercise > 120 min/week
Non-smoking

Exclusion Criteria

Active treatment for cancer, stroke (< 6 mo), peripheral vascular disease, coronary artery disease (myocardial infarction <6 mo), state III, IV Congestive Heart Failure, valvular heart disease, major psychiatric disease, severe anemia, liver or renal disease, diabetes, severe osteoarthritis, blindness or deafness, fracture in upper or lower extremity within the last 6 months, upper or lower extremity amputation, anticoagulant therapy (aspirin use is permitted), parkinsons disease
Failure to give consent
Anabolic medications (growth hormone or testosterone)
High amounts of physical activity (i.e. running, bicycling etc > 120 min/week).
Dementing illness
Smoking
Pregnant
Significant cognitive impairment; Mini-Mental State (MMSE) exam < 24
Statin Usage
Excessive alcohol use (>2 drinks per day)
Resting heart rate > 120 bpm
Systolic blood pressure > 180 mmHg
Diastolic blood pressure > 110 mmHg
History of significant head injury
Anticholinesterase inhibitor (such as Aricept)
Contraindications to MRI (e.g. cardiac pacemaker, implanted cardiac defibrillator, aneurysm clip, claustrophobia, etc.)
Current Use of Antidepressant Medications

Study & Design

Study Type: OBSERVATIONAL

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Muscle Satellite Cells	Baseline, 2 days post-injury, 7 days post-injury	Change in the number of myonuclear cells identified as Pax7+ following contraction-induced skeletal muscle injury. Cells identified as Pax7+ by immunohistochemistry of skeletal muscle biopsy samples. Data adjusted for gender, physical activity level, and baseline satellite cell number.

Secondary Outcome Measures