title: U-shaped relationship between serum uric acid levels and intrarenal hemodynamic parameters in healthy subjects.
abstract: Hyperuricemia has been reported to affect renal hemodynamics. In a recent study, both low and high levels of serum uric acid (SUA) were found to be associated with loss of kidney function. The goal of this study was to evaluate the relationship between SUA levels and intrarenal hemodynamic parameters in healthy subjects, using plasma clearance of para-aminohippurate (CPAH) and inulin (Cin). Renal and glomerular hemodynamics were evaluated by simultaneous measurements of CPAHand Cinin 48 healthy subjects (54.6 ± 13.4 yr). Intrarenal hemodynamic parameters, including efferent and afferent (Ra) arteriolar resistance, were calculated using Gómez's formulas. Relationships of SUA levels with these intrarenal hemodynamic parameters were examined. In quadratic regression analysis, SUA levels had a significant inverse U-shaped relationship with Cin(P< 0.0001,R2= 0.350) and CPAH(P= 0.0093,R2= 0.188) and a U-shaped relationship with Ra(P= 0.0011,R2= 0.262). In multiple regression analysis with normal (3.5-6.0 mg/dl) and mildly low or high (<3.5 or >6.0 mg/dl) SUA levels entered as dummy variables of zero and one, respectively, mildly low or high SUA levels were significantly and independently associated with Ra(β = 0.230,P= 0.0403) after adjustment for several factors (R2= 0.597,P< 0.0001). Both mild hyperuricemia and mild hypouricemia are significantly associated with increased Ra, although weakly. The increase in Rain subjects with mild hyperuricemia or hypouricemia may be related to renal hemodynamic abnormalities, possibly leading to a decline in renal function.
authors.affiliation: Departments of Nephrology, and Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan; and.
authors.forename: Hideki
authors.initials: H
authors.lastname: Uedono
authors.affiliation: Departments of Nephrology, and Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan; and naranotsudadesu@infoseek.jp.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Tsuda
authors.affiliation: Departments of Nephrology, and Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan; and.
authors.forename: Eiji
authors.initials: E
authors.lastname: Ishimura
authors.affiliation: Departments of Nephrology, and Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan; and.
authors.forename: Shinya
authors.initials: S
authors.lastname: Nakatani
authors.affiliation: Departments of Nephrology, and Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan; and.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Kurajoh
authors.affiliation: Departments of Nephrology, and Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan; and.
authors.forename: Katsuhito
authors.initials: K
authors.lastname: Mori
authors.affiliation: Department of Urology, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Uchida
authors.affiliation: Departments of Nephrology, and Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan; and.
authors.forename: Masanori
authors.initials: M
authors.lastname: Emoto
authors.affiliation: Department of Urology, Osaka City University Graduate School of Medicine, Osaka, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nakatani
authors.affiliation: Departments of Nephrology, and Metabolism, Endocrinology, and Molecular Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan; and.
authors.forename: Masaaki
authors.initials: M
authors.lastname: Inaba
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D005260:Female; D005919:Glomerular Filtration Rate; D064368:Healthy Volunteers; D006439:Hemodynamics; D006801:Humans; D033461:Hyperuricemia / Q000097:blood* / Q000503:physiopathology*; D007262:Infusions, Intravenous; D007444:Inulin / Q000008:administration & dosage / Q000378:metabolism; D007668:Kidney / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D012044:Regression Analysis; D012079:Renal Circulation; D017595:Renal Plasma Flow; D014527:Uric Acid / Q000097:blood*; D010130:p-Aminohippuric Acid / Q000008:administration & dosage / Q000378:metabolism
chemical_list: D015415:Biomarkers; D014527:Uric Acid; D007444:Inulin; D010130:p-Aminohippuric Acid
keywords: inulin clearance; para-aminohippurate clearance; renal hemodynamics