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Am J Physiol Regul Integr Comp Physiol. 2015 Feb 1;308(3):R208-18. doi: 10.1152/ajpregu.00409.2014. Epub 2014 Dec 4.

Tetrahydrobiopterin lowers muscle sympathetic nerve activity and improves augmentation index in patients with chronic kidney disease.

Author information

1
Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Research Service Line, Department of Veterans Affairs Medical Center, Decatur, Georgia; jeanie.park@emory.edu.
2
Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, Atlanta, Georgia; and.
3
Cardiology Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia.
4
Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia; Research Service Line, Department of Veterans Affairs Medical Center, Decatur, Georgia;

Abstract

Chronic kidney disease (CKD) is characterized by overactivation of the sympathetic nervous system (SNS) that contributes to cardiovascular risk. Decreased nitric oxide (NO) bioavailability is a major factor contributing to SNS overactivity in CKD, since reduced neuronal NO leads to increased central SNS activity. Tetrahydrobiopterin (BH4) is an essential cofactor for nitric oxide synthase that increases NO bioavailability in experimental models of CKD. We conducted a randomized, double-blinded, placebo-controlled trial testing the benefits of oral sapropterin dihydrochloride (6R-BH4, a synthetic form of BH4) in CKD. 36 patients with CKD and hypertension were randomized to 12 wk of 1) 200 mg 6R-BH4 twice daily + 1 mg folic acid once daily; vs. 2) placebo + folic acid. The primary endpoint was a change in resting muscle sympathetic nerve activity (MSNA). Secondary endpoints included arterial stiffness using pulse wave velocity (PWV) and augmentation index (AIx), endothelial function using brachial artery flow-mediated dilation and endothelial progenitor cells, endothelium-independent vasodilatation (EID), microalbuminuria, and blood pressure. We observed a significant reduction in MSNA after 12 wk of 6R-BH4 (-7.5 ± 2.1 bursts/min vs. +3.2 ± 1.3 bursts/min; P = 0.003). We also observed a significant improvement in AIx (by -5.8 ± 2.0% vs. +1.8 ± 1.7 in the placebo group, P = 0.007). EID increased significantly (by +2.0 ± 0.59%; P = 0.004) in the 6R-BH4 group, but there was no change in endothelial function. There was a trend toward a reduction in diastolic blood pressure by -4 ± 3 mmHg at 12 wk with 6R-BH4 (P = 0.055). 6R-BH4 treatment may have beneficial effects on SNS activity and central pulse wave reflections in hypertensive patients with CKD.

KEYWORDS:

autonomic function; blood pressure; nitric oxide; sympathetic activity; vascular stiffness

PMID:
25477424
PMCID:
PMC4313073
DOI:
10.1152/ajpregu.00409.2014
[Indexed for MEDLINE]
Free PMC Article

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