Chronic hemiparetic stroke is associated changes in body composition, skeletal muscle and cardiometabolic health; specific changes include paretic limb muscular atrophy, increased intramuscular fat deposition, elevated prevalence of impaired glucose tolerance and type 2 diabetes. This randomized intervention study compares a 6 month task oriented exercise programs versus control with both groups receiving best medical stroke care according to American Stroke Association "Get with the Guidelines". The hypothesis is that is 6 months of task-oriented exercise initiated early across the sub-acute period of stroke can prevent or ameliorate the natural course of these body composition, skeletal muscle and cardiometabolic health changes.
Stroke leads to profound cardiovascular deconditioning and secondary abnormalities in paretic skeletal muscle that worsen cardiovascular health. Conventional rehabilitation focuses on restoration of daily function, without an adequate exercise stimulus to address deconditioning or the muscle abnormalities that may propagate insulin resistance (IR) to worsen risk for type 2 diabetes mellitus (T2DM) and recurrent stroke. By the time individuals reach chronic stroke (>6 months), we report hemiparetic body composition abnormalities including paretic leg muscular atrophy, increased intramuscular area fat, and a major shift to fast myosin heavy chain (MHC). All of these factors promote IR, which has been linked to reduced muscle protein synthesis in aging that may be reversible with exercise. We also find elevated tumor necrosis factor alpha (TNFα) in paretic leg muscle, suggesting that inflammation may affect protein synthesis and breakdown, similar to sarcopenia in aging. Yet, no prior studies have considered stroke as a catabolic syndrome modifiable by early exercise to improve muscle and cardiometabolic health.
Aim #1. Paretic (P) and non-paretic (NP) leg mixed muscle protein synthesis and breakdown in the fed and fasted state, TNFα expression, thigh muscle volume and strength.
Hypothesis 1: Paretic leg has reduced muscle protein synthesis and increased breakdown compared to non-paretic leg; TEXT will increase mixed muscle protein synthesis and reduce breakdown to increase muscle volume and strength by the mechanism(s) of reducing inflammation in the paretic leg, compared to controls.
Aim # 2. Glucose tolerance, fitness, and muscle phenotype. Hypothesis 2: TEXT will improve fitness levels, insulin and glucose response to oral glucose challenge, and increase paretic leg slow twitch (slow MHC) muscle molecular phenotype.
This randomized study investigates the hypothesis that in African-Jamaican adults with recent hemiparetic stroke, 6 months of TEXT across the sub-acute and into the chronic phase of stroke will improve paretic leg muscle and cardiometabolic health, compared to controls receiving best medical care.
Phase 1 consists of recruitment and screening of individuals with mild to moderate hemiparetic stroke from UWI Accident and Emergency Room and Neurology Stroke Clinics. Phase 2: Subjects with hemiparetic gait ≤ 8 weeks post-stroke who are not wheelchair bound or bed are approached for informed consent, medical, neurologic, blood tests, and treadmill (TM) exercise tests to determine study eligibility. Phase 3 baseline testing includes measures of fitness, oral glucose tolerance test (OGTT), body composition, bilateral vastus lateralis muscle biopsies, stable isotope measures of protein synthesis and breakdown. Phase 4: Eligible subjects are randomized to 6 months 3x/week TEXT or control group with best medical care alone that includes American Stroke Association (ASA) physical activity guideline recommendations for walking 4x/week. Randomization is stratified based on glucose tolerance (normal vs. abnormal) and gait deficit severity. Subjects have limited 3 month testing of fitness levels (VO2 peak), body composition, fasting glucose and insulin levels to document the natural history (controls) and temporal profile of exercise-mediated adaptations (TEXT) as they transition from the sub-acute into chronic phase of stroke. Phase 5 is 6-month post-intervention testing.
- Task Oriented Exercise Training Procedure
Intervention Desc: Treadmill training with safety harnesses begin at 6 to 15 minutes total duration at 40-50% maximal heart rate reserve 3 times per week, increasing to 60-70% maximal heart rate reserve for 30 minutes for 6 months. Group dynamic balance exercise immediately follow the treadmill training 3 times a week. Participants also receive Best Stroke Care according to "Get with the Guidelines" ARM 1: Kind: Experimental Label: Exercise Description: Task-oriented exercise training (aerobic, strength, and balance exercises)
- Stroke Care "Get with the Guidelines" Procedure
Intervention Desc: Post-stroke care is applied according to the recommendations of the American Stroke Association "Get with the Guidelines" adapted for Jamaica ARM 1: Kind: Experimental Label: Stroke Care Description: Best Medical Care in Jamaica adapted from the American Stroke Association "Get with the Guidelines".
- Allocation: Randomized
- Masking: Open Label
- Purpose: Treatment
- Endpoint: Safety/Efficacy Study
- Intervention: Parallel Assignment
|Type||Measure||Time Frame||Safety Issue|
|Primary||Thigh and Abdominal muscle and fat||Baseline and 6 months||No|
|Primary||Whole body protein and skeletal muscle synthesis and breakdown||Baseline and 6 months||No|
|Primary||Muscle myosin heavy chain isoform (MHC) proportions||Baseline and 6 months||No|
|Primary||Leg Strength||Baseline and 6 months||No|
|Primary||Fitness||Baseline and 6 months||No|
|Primary||Glucose tolerance||Baseline and 6 months||No|
|Secondary||Muscle TNF alpha||Baseline and 6 months||No|
|Secondary||Mobility and balance||Baseline and 6 months||No|