Neurovascular Regulation During Exercise in Humans With Chronic Kidney Disease
Emory University
Summary
The purpose of this study is to find out why patients with chronic kidney disease (CKD) have poor exercise capacity and to explore what causes an increase in blood pressure during exercise (i.e. increased adrenaline levels, or decreased ability of blood vessels to dilate). This study will also test whether or not regular exercise on a bicycle and/or treatment with 6R-BH4 (Kuvan) pills, or histidine and beta-alanine supplementation improves these measures during exercise. 6R-BH4 is currently FDA-approved for use in patients with certain forms of a disease called phenylketonuria, but it is not currently FDA approved for blood pressure or exercise capacity in people with CKD.
Description
The major problem addressed in this study is to understand mechanisms underlying poor exercise capacity in patients with chronic kidney disease (CKD). Prior research has found that CKD patients have an exaggerated increase in blood pressure during certain forms of exercise that could contribute to exercise dysfunction as well as cardiovascular disease. This study will test the mechanisms underlying this exaggerated blood pressure response, as well as the potential benefits of simple measures such as exercise training on a stationary bicycle, and treatment with 6R-BH4, a drug that is currently…
Eligibility
- Age range
- 18–75 years
- Sex
- All
- Healthy volunteers
- No
Inclusion Criteria for Chronic Kidney Disease Patients: * Stage III or IV Chronic Kidney Disease, defined as reduction in estimated glomerular filtration rate (eGFR) to 15-59 cc/minute as calculated by the modified Modification of Diet in Renal Disease (MDRD) Study equation or the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation * Stable renal function, with no greater than a 30% reduction in eGFR over the prior 3 months * Does not exercise regularly (defined as exercising less than 20 minutes twice per week) * Willing and able to cooperate with the study protocol Inclusi…
Interventions
- Drug6R-BH4
Participants will receive 200 mg of 6R-BH4 twice daily for 12 weeks. Study pills are dissolved in water or apple juice, and taken with food.
- Other6R-BH4 placebo
Participants will receive a placebo that is identical to 200 mg of 6R-BH4. The placebo will be taken twice daily for 12 weeks. Study pills are dissolved in water or apple juice, and taken with food.
- Dietary SupplementFolic acid
Participants will take 1 mg of folic acid daily for 12 weeks. Folic acid is given because it enhances the binding affinity of BH4 to nitric oxide synthase (NOS), and also enhances the regeneration of BH4 from inactive BH2
- OtherExercise training
Participants will exercise 3 times a week on a stationary ergometer. Exercise intensity will begin at low levels (50% of maximal heart rate reserve) calculated utilizing the Karvonen method. Briefly, target exercise heart rate (HR) is calculated by subtracting the persons age from 220. Resting heart rate is then subtracted from this number. The answer is then multiplied by the target percent (50% for example) and the product is added back to resting heart rate to provide the target exercise session heart rate. Intensity will be increased by 5% every week (as tolerated by the participant) to a maximum of 80% of maximal heart rate. Exercise time will progress from an initial 20 minutes per session to a maximum of 45 minutes by increasing 5 minutes each week.
Locations (3)
- Emory University Hospital MidtownAtlanta, Georgia
- Emory University HospitalAtlanta, Georgia
- Atlanta VA Health Care SystemDecatur, Georgia