Claudication, defined as walking-induced leg discomfort and gait dysfunction relieved by rest, affects 5% of Americans over 55 years of age. Claudicating patients adopt sedentary lifestyles and cluster at the extreme low end of the physical activity spectrum, escalating risk for adverse health effects. The primary therapeutic goals for claudicating patients are restoration of leg function and prevention of disease progression. Current, rehabilitative interventions focus on inadequate blood flow as the only cause of claudication. Operative revascularization and/or exercise therapy are the principal conventional therapeutic modalities, providing only modest rehabilitative benefit. Applying biomechanical analysis to gait of claudicating patients, our team has developed preliminary data indicating that blood flow is not the only mechanism producing the limb dysfunction of claudication. Several laboratories including our own have demonstrated a myopathy, characterized by mitochondrial dysfunction, oxidative damage and inflammation, in leg skeletal muscle of claudicating patients. These conditions have not been quantified, comprehensively, in relation to claudication, and their association with severity of claudication is not known. Our hypothesis is that blood flow restriction is not a good predictor of limb dysfunction in claudication, whereas muscle mitochondrial dysfunction, oxidative damage and inflammation are strong predictors of limb dysfunction both at baseline and after conventional therapy with revascularization or supervised exercise.
Under Aim #1, we will acquire precise measurements of gastrocnemius mitochondrial function, oxidative damage and inflammation in claudicating patients, at the time of their initial presentation, and evaluate these measurements as predictors of objective measures of limb function and subjective measures of quality of life.
Under Aims #2 and #3, we will evaluate the effects of revascularization (Aim#2) and supervised exercise therapy (Aim#3) on mitochondrial dysfunction, oxidative damage and inflammation in claudicating gastrocnemius and on objective measures of limb function and subjective measures of quality of life. If our hypothesis is correct, the work in Aim #2 will for the first time definitively demonstrate that blood flow restriction due to blockages in the arterial tree is not the only cause of claudication. The work under Aims #2 and #3 will determine whether revascularization or exercise therapy has a beneficial effect on the myopathy of claudicating muscle with associated improvement in limb function and quality of life. Finally, the proposed studies under Aims #1, #2 and #3 will provide quantitative modeling of a panel of mechanistic (bioenergetics, oxidative stress and inflammation) parameters as predictors of objective measurements of claudicating limb function and subjective measures of quality of life commonly used for clinical assessment. Measurements of gastrocnemius mitochondrial function, oxidative damage and inflammation may be useful tools that permit staging of disease for optimum intervention and evaluation of therapeutic interventions that specifically target these conditions, improving rehabilitative outcomes.

Public Health Relevance

Intermittent claudication afflicts 5% of the US population older than 55 years of age and develops along with hardening of the arteries of the legs. Claudicating patients limp and can only walk very short distances because their legs hurt. Our protocol evaluates the mechanisms that may produce the leg dysfunction of claudication and its successful completion can ultimately produce significant new diagnostic and treatment strategies for the care of claudicating patients.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
5R01AG034995-05
Application #
8723021
Study Section
Bioengineering, Technology and Surgical Sciences Study Section (BTSS)
Program Officer
Zieman, Susan
Project Start
2010-09-15
Project End
2015-05-31
Budget Start
2014-06-15
Budget End
2015-05-31
Support Year
5
Fiscal Year
2014
Total Cost
$1,050,368
Indirect Cost
$282,600
Name
University of Nebraska Medical Center
Department
Surgery
Type
Schools of Medicine
DUNS #
168559177
City
Omaha
State
NE
Country
United States
Zip Code
68198
Myers, Sara A; Applequist, Bryon C; Huisinga, Jessie M et al. (2016) Gait kinematics and kinetics are affected more by peripheral arterial disease than by age. J Rehabil Res Dev 53:229-38
Chien, Jung Hung; Mukherjee, Mukul; Siu, Ka-Chun et al. (2016) Locomotor Sensory Organization Test: How Sensory Conflict Affects the Temporal Structure of Sway Variability During Gait. Ann Biomed Eng 44:1625-35
Ha, Duy M; Carpenter, Lauren C; Koutakis, Panagiotis et al. (2016) Transforming growth factor-beta 1 produced by vascular smooth muscle cells predicts fibrosis in the gastrocnemius of patients with peripheral artery disease. J Transl Med 14:39
Koutakis, Panagiotis; Miserlis, Dimitrios; Myers, Sara A et al. (2015) Abnormal accumulation of desmin in gastrocnemius myofibers of patients with peripheral artery disease: associations with altered myofiber morphology and density, mitochondrial dysfunction and impaired limb function. J Histochem Cytochem 63:256-69
Vallabhajosula, Srikant; Tan, Chi Wei; Mukherjee, Mukul et al. (2015) Biomechanical analyses of stair-climbing while dual-tasking. J Biomech 48:921-9
Harrison, Steven J; Stergiou, Nicholas (2015) Complex Adaptive Behavior and Dexterous Action. Nonlinear Dynamics Psychol Life Sci 19:345-94
Thompson, J R; Swanson, S A; Haynatzki, G et al. (2015) Protein concentration and mitochondrial content in the gastrocnemius predicts mortality rates in patients with peripheral arterial disease. Ann Surg 261:605-10
Rand, Troy J; Wurdeman, Shane R; Johanning, Jason M et al. (2015) Increased minimum toe clearance variability in patients with peripheral arterial disease. Med Eng Phys 37:1141-5
Koutakis, Panagiotis; Myers, Sara A; Cluff, Kim et al. (2015) Abnormal myofiber morphology and limb dysfunction in claudication. J Surg Res 196:172-9
Koutakis, Panagiotis; Weiss, Dustin J; Miserlis, Dimitrios et al. (2014) Oxidative damage in the gastrocnemius of patients with peripheral artery disease is myofiber type selective. Redox Biol 2:921-8

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