An association between hyperuricemia and hypertension has been observed repeatedly since the 1870s. Generally the link was dismissed as having no causal role because of an assumption that the increase in serum uric acid was merely a surrogate for decreased glomerular filtration rate. Recently the association has been reevaluated because of results from several large clinical trials that implicate hyperuricemia as an independent risk factor for poor cardiovascular outcomes. Our own data demonstrates a close correlation between serum uric acid and primary hypertension in children. Furthermore, data from experiments using a model of mild hyperuricemia in rats reveal that the hyperuricemia alone is (1) sufficient to lead to hypertension and (2) exacerbates the progressive renal injury associated with either Cyclosporin A nephrotoxicity or surgical 5/6 nephrectomy. In the animal model, the mechanisms involved in these processes include uric acid mediated activation of cyclooxygenase-II, activation of the renin angiotensin system and down regulation of renal nitric oxide synthase. If these animal studies can be generalized to human populations, control of mild hyperuricemia will provide a new approach to management of hypertension as well as a novel therapeutic target for the prevention of progressive renal disease and cardiovascular morbidity. We propose to test whether the use of the xanthine oxidase inhibitor allopurinol, a uric acid lowering drug, will (1) ameliorate primary hypertension in children and (2) control hypertension in renal transplant recipients receiving cyclosporin or tacrolimus. We will further investigate the physiological mechanism by which serum uric acid levels are elevated in hypertensive children and the biochemical mechanisms by which elevated serum uric acid lead to increased blood pressure.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Mentored Patient-Oriented Research Career Development Award (K23)
Project #
3K23DK064587-03S1
Application #
7292992
Study Section
Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Program Officer
Moen, Laura K
Project Start
2003-09-01
Project End
2008-08-31
Budget Start
2005-09-01
Budget End
2006-08-31
Support Year
3
Fiscal Year
2006
Total Cost
$1,000
Indirect Cost
Name
Baylor College of Medicine
Department
Pediatrics
Type
Schools of Medicine
DUNS #
051113330
City
Houston
State
TX
Country
United States
Zip Code
77030
Feig, Daniel I; Soletsky, Beth; Johnson, Richard J (2008) Effect of allopurinol on blood pressure of adolescents with newly diagnosed essential hypertension: a randomized trial. JAMA 300:924-32
Feig, Daniel I; Kang, Duk-Hee; Johnson, Richard J (2008) Uric acid and cardiovascular risk. N Engl J Med 359:1811-21
Swartz, Sarah J; Srivaths, Poyyapakkam R; Croix, Beth et al. (2008) Cost-effectiveness of ambulatory blood pressure monitoring in the initial evaluation of hypertension in children. Pediatrics 122:1177-81
Feig, Daniel I; Johnson, Richard J (2007) The role of uric acid in pediatric hypertension. J Ren Nutr 17:79-83
Podoll, Amber; Grenier, Michelle; Croix, Beth et al. (2007) Inaccuracy in pediatric outpatient blood pressure measurement. Pediatrics 119:e538-43
Feig, Daniel I; Mazzali, Marilda; Kang, Duk-Hee et al. (2006) Serum uric acid: a risk factor and a target for treatment? J Am Soc Nephrol 17:S69-73
Croix, Beth; Feig, Daniel I (2006) Childhood hypertension is not a silent disease. Pediatr Nephrol 21:527-32
Feig, Daniel I; Rodriguez-Iturbe, Bernardo; Nakagawa, Takahiko et al. (2006) Nephron number, uric acid, and renal microvascular disease in the pathogenesis of essential hypertension. Hypertension 48:25-6
Feig, Daniel I (2005) Uric acid and hypertension in adolescents. Semin Nephrol 25:32-8
Feig, Daniel I; Nakagawa, Takahiko; Karumanchi, S Ananth et al. (2004) Hypothesis: Uric acid, nephron number, and the pathogenesis of essential hypertension. Kidney Int 66:281-7

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