Influence Of Endothelial Function On Central and Peripheral Causes Of Exercise Impairment In Type 2 Diabetes
Overview
- Phase
- Not Applicable
- Intervention
- Exercise program
- Conditions
- Type 2 Diabetes
- Sponsor
- University of Colorado, Denver
- Enrollment
- 47
- Locations
- 1
- Primary Endpoint
- Percent Change in Circumferential Strain Before and After Exercise at Baseline, After Vitamin C Infusion, and After Exercise Training
- Status
- Completed
- Last Updated
- 2 years ago
Overview
Brief Summary
This study will evaluate the effects of impaired blood flow regulation on exercise. It will also determine whether the effects are more important in the heart or in the skeletal muscle tissue during exercise. In addition, this study will decide whether temporarily reversing these problems will improve blood flow control, improve heart and muscle tissue function and help improve exercise capacity in person with type 2 diabetes. This study will do so using two methods: (1) by giving vitamin C intravenously (IV) and (2) a three month exercise training program. Up to 100 subjects will be enrolled in this study.
Detailed Description
The investigators have found that persons with type 2 diabetes have an impaired ability to perform exercise even without clinically apparent complications. The reasons for this marked abnormality are unknown but are important as the decreased ability to exercise could contribute to the decreased expenditure of physical activity frequently observed in this population and may potentially constitute an early marker of cardiovascular disease. The investigators wish to evaluate the effects of impaired blood flow regulation on exercise capacity and whether the effects are more important in the heart or in the skeletal muscle tissue during exercise. In addition, the investigators are determining whether correcting these abnormalities by two methods of improving blood flow regulation (acutely infusing Vitamin C or three months of chronic exercise training) leads to improved blood flow regulation, improved heart and skeletal muscle tissue function and hence to better exercise capacity in person with type 2 diabetes. This information will provide a more mechanistic understanding of causes of abnormal exercise responses observed in person with type 2 diabetes as well as whether and to what degree responses are modifiable. Interventions that reverse the exercise defect may facilitate patient adherence to prescribed physical activity programs and potentially decrease cardiovascular mortality in this large segment of the population.
Investigators
Eligibility Criteria
Inclusion Criteria
- •Men and women with uncomplicated Type 2 Diabetes
- •Healthy men and women without Type 2 Diabetes
- •Patients with Type 2 Diabetes may be taking metformin or sulfonylurea drugs to treat diabetes
- •Persons with history of hypercholesteremia if controlled with statins and/or diet
- •Patients who are moderately overweight (BMI 25-37.5)
- •Must be sedentary (defined as regular exercise \< 2 times a week at a low to moderate level).
- •Patients with Hemoglobin A1c (HBA1C) \<8%
- •Patients between the ages of 30 to 55 years
- •Premenopausal women.
- •Former smokers who have quit smoking for at least one year
Exclusion Criteria
- •People with T2DM taking oral medications, other than metformin or sulfonylurea drugs to control their diabetes.
- •Persons treated with insulin will be excluded
- •People who are currently smoking or have not quit for at least one year
- •Controls who have immediate family history of T2DM
- •Peri-menopausal or post-menopausal women.
- •Peripheral neuropathy
- •Total cholesterol \> 205
- •Regional wall motion abnormalities
- •LV wall thickness ≥1.1 cm
- •Decreased contractility (fractional shortening \<30%)
Arms & Interventions
Ascorbic acid
All study subjects have ascorbic acid infusion during one exercise visit as well as a three month exercise training intervention.
Intervention: Exercise program
Ascorbic acid
All study subjects have ascorbic acid infusion during one exercise visit as well as a three month exercise training intervention.
Intervention: Ascorbic Acid (Vitamin C)
Outcomes
Primary Outcomes
Percent Change in Circumferential Strain Before and After Exercise at Baseline, After Vitamin C Infusion, and After Exercise Training
Time Frame: 7 months; Measures are made at rest and after exercise for baseline, at rest and after infusion for Vitamin C administration, and at rest and after exercise following the exercise training
Characterize the purported cardiac dysfunction during exercise in people with type 2 diabetes (T2D). In a normal patient when measuring circumferential strain, results are negative with downward tracing (as strain is a relative change in length). Circumferential strain is a measurement of ventricular circumference within the heart vessels, measured via echocardiography.
Ejection Fraction: Percentage of Blood Leaving the Heart Before and After Exercise at Baseline, After a Vitamin C Infusion, and After Exercise Training
Time Frame: 7 months; Measures are made at rest for baseline, at rest for Vitamin C administration, and at rest following the exercise training
Evaluate potential changes in cardiac function by echocardiography following 2 interventions: Three months of exercise training and acute vitamin C administration. Ejection fraction (EF) is a measurement of the percentage of blood leaving your heart each time it contracts, typically measure by echocardiography. Numbers listed are absolute EF values.