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| ID | Type | Description | Link |
|---|---|---|---|
| R01HL135183 | U.S. NIH Grant/Contract | View source | |
| 2025P010140 | Other Identifier | Emory IRB |
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| Name | Class |
|---|---|
| National Heart, Lung, and Blood Institute (NHLBI) | NIH |
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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.
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 FDA-approved for the treatment of phenylketonuria, but has been shown to have beneficial effects on vascular health in patients with kidney disease. This study will also examine the effects of exercise with histidine and beta-alanine supplementation. Histidine and beta-alanine are two over-the-counter supplements commonly used to enhance sports performance in athletes.
Prior to the intervention portion of this study, the researchers will measure how much the vein constricts in response to adrenaline in CKD patients versus controls. The study will also measure muscle pH, and muscle oxygenation during exercise in CKD patients and controls.
The intervention portion of the study will test whether aerobic exercise training with and without 6R-BH4, or with and without histidine and beta-alanine supplementation might help muscle pH and adrenaline levels, vascular reactivity, muscle oxygenation, and the exaggerated blood pressure response during exercise in CKD patients. Participants will be randomized using a 2x2 factorial design to exercise training (ET) with 6R-BH4, ET with placebo, stretching (control condition to exercise) with 6R-BH4, and stretching with placebo. Participants will undergo exercise training on a stationary bicycle, or stretching exercises, 3 times per week for 6-14 weeks (depending on availability of the participant).
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Exercise training + 6R-BH4 | Experimental | Participants randomized to this arm will exercise on a stationary bicycle for 20-45 minutes, 3 times per week, for 6-12 weeks. This arm will also take the study drug 6R-BH4. |
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| Exercise training + 6R-BH4 placebo | Active Comparator | Participants randomized to this arm will exercise on a stationary bicycle for 20-45 minutes, 3 times per week, for 6-12 weeks. This arm will also take a placebo to match the study drug 6R-BH4. |
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| Stretching + 6R-BH4 | Active Comparator | Participants randomized to this arm will do muscle stretching and toning for 20-45 minutes, 3 times per week, for 6-12 weeks. This arm will also take the study drug 6R-BH4. |
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| Stretching + placebo | Placebo Comparator | Participants randomized to this arm will do muscle stretching and toning for 20-45 minutes, 3 times per week, for 6-12 weeks. This arm will also take a placebo instead of the active study drug. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| 6R-BH4 | Drug | 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. |
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| Measure | Description | Time Frame |
|---|---|---|
| Change in functional sympatholysis | Muscle oxygenation during exercise and sympathoexcitation will be measured. | Baseline, Week 12 |
| Change in vascular alpha 1 adrenergic responsiveness | Changes in vascular diameter in response to phenylephrine will be measured. | Baseline, Week 12 |
| Change in exaggerated pressor responses during exercise | Blood pressure and sympathetic responses during exercise will be measured. | Baseline, Week 12 |
| Measure | Description | Time Frame |
|---|---|---|
| Renal artery resistance during exercise | Renal artery blood flow will be measured. | Baseline, Week 12 |
| Change in endothelial function | Endothelial function using peripheral arterial tonometry will be measured. |
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Inclusion Criteria for Chronic Kidney Disease Patients:
Inclusion Criteria for Control Study Participants:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Jeanie Park, MD | Contact | 404-727-2525 | jeanie.park@emory.edu |
| Name | Affiliation | Role |
|---|---|---|
| Joe Nocera, PhD | Emory University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Emory University Hospital Midtown | Recruiting | Atlanta | Georgia | 30308 | United States |
| PubMed Identifier | Type | Citation | Retractions |
|---|---|---|---|
| 36810250 | Derived | Jeong J, Sprick JD, DaCosta DR, Mammino K, Nocera JR, Park J. Exercise modulates sympathetic and vascular function in chronic kidney disease. JCI Insight. 2023 Feb 22;8(4):e164221. doi: 10.1172/jci.insight.164221. |
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| Exercise training + histidine and beta-alanine |
| Active Comparator |
Participants randomized to this arm will exercise on a stationary bicycle for 20-45 minutes, 3 times per week, for 6-12 weeks. This arm will also take histidine and beta-alanine supplementation. |
|
| Exercise training + histidine and beta-alanine placebo | Active Comparator | Participants randomized to this arm will exercise on a stationary bicycle for 20-45 minutes, 3 times per week, for 6-12 weeks. This arm will also take a placebo to match the histidine and beta-alanine supplementation. |
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| 6R-BH4 placebo | Other | 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. |
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| Folic acid | Dietary Supplement | 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 |
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| Exercise training | Other | 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. |
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| Stretching | Other | Participants randomized to 'No Exercise Training' group will instead of aerobic exercise, undergo progressive whole body stretching and toning exercises designed for individuals 65 and older. This type of low intensity activity is designed not to increase heart rate and will serve as the Control group to the Exercise Training group. The Control group will come in for stretching sessions 3 times per week for 20-45 minutes. |
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| Histidine and beta-alanine supplementation | Dietary Supplement | Histidine and beta-alanine are two over-the-counter supplements commonly used to enhance sports performance in athletes. Participants randomized to this study arm will receive combined histidine (4g/day) and beta-alanine (3.2g/day) supplementation. |
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| Histidine and beta-alanine placebo | Other | Participants randomized to this study arm will receive a placebo to match combined histidine (4g/day) and beta-alanine (3.2g/day) supplementation. |
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| Baseline, Week 12 |
| Change in vascular stiffness | Vascular stiffness using applanation tonometry. | Baseline, Week 12 |
| Emory University Hospital | Recruiting | Atlanta | Georgia | 30322 | United States |
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| Atlanta VA Health Care System | Recruiting | Decatur | Georgia | 30033 | United States |
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| ID | Term |
|---|---|
| D051436 | Renal Insufficiency, Chronic |
| D006973 | Hypertension |
| D007674 | Kidney Diseases |
| ID | Term |
|---|---|
| D051437 | Renal Insufficiency |
| D014570 | Urologic Diseases |
| D052776 | Female Urogenital Diseases |
| D005261 | Female Urogenital Diseases and Pregnancy Complications |
| D000091642 | Urogenital Diseases |
| D052801 | Male Urogenital Diseases |
| D002908 | Chronic Disease |
| D020969 | Disease Attributes |
| D010335 | Pathologic Processes |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D014652 | Vascular Diseases |
| D002318 | Cardiovascular Diseases |
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| ID | Term |
|---|---|
| C003402 | sapropterin |
| D005492 | Folic Acid |
| D015444 | Exercise |
| D006639 | Histidine |
| ID | Term |
|---|---|
| D011622 | Pterins |
| D011621 | Pteridines |
| D006574 | Heterocyclic Compounds, 2-Ring |
| D000072471 | Heterocyclic Compounds, Fused-Ring |
| D006571 | Heterocyclic Compounds |
| D009043 | Motor Activity |
| D009068 | Movement |
| D009142 | Musculoskeletal Physiological Phenomena |
| D055687 | Musculoskeletal and Neural Physiological Phenomena |
| D000598 | Amino Acids, Cyclic |
| D000596 | Amino Acids |
| D000602 | Amino Acids, Peptides, and Proteins |
| D000601 | Amino Acids, Essential |
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