Asymmetric dimethylarginine, blood pressure, and renal perfusion in elderly subjects.
BACKGROUND
Reduced availability of nitric oxide (NO) is thought to contribute to the age-associated increase of renovascular tone and blood pressure. We assessed blood concentrations of the endogenous NO synthase inhibitor asymmetric dimethylarginine (ADMA) as well as renal hemodynamics, comparing young (n=24, 13 men, 25+/-1 years) and elderly (n=24, 13 men, 69+/-2 years) healthy subjects and elderly subjects with essential hypertension (n=24, 13 men, 70+/-2 years).


RESULTS
Plasma ADMA concentration and renovascular resistance (RVR) were significantly higher (P<0.05) and effective renal plasma flow (ERPF) significantly lower (P<0.05) in elderly (2.77+/-0.20 micromol/L, 125+/-10 mm Hg/mL per minute, 487+/-26 mL/min per 1.73 m2) than in young healthy subjects (1.30+/-0.11, 77+/-3, 654+/-18). Both ADMA levels and RVR were higher and ERPF lower in the hypertensive elderly subjects (3.53+/-0.23, 163+/-11, 427+/-19; P<0.05 versus both groups). In contrast, plasma concentrations of the biologically inactive stereoisomer symmetric dimethylarginine, l-arginine, and homocysteine were similar in the 3 groups studied. In the logistic regression analysis only ADMA was an independent determinant of both ERPF (P<0.001; r2=0.80) and RVR (P<0.002; r2=0.86). In addition, ADMA (P<0.002) and serum glucose (P<0.036) were independently related (r2=0.67) to the level of blood pressure.


CONCLUSIONS
These results are compatible with the notion that accumulation of the endogenous NO synthase inhibitor ADMA in senescent individuals is involved in the decrease of renal perfusion and increase of blood pressure.
Kielstein
Jan T
JT
Department of Internal Medicine, Medical School Hannover, Germany.
Bode-Böger
Stefanie M
SM
Frölich
Jürgen C
JC
Ritz
Eberhard
E
Haller
Hermann
H
Fliser
Danilo
D
D000328:Adult; D000368:Aged; D000375:Aging; D001120:Arginine / Q000031:analogs & derivatives* / Q000097:blood*; D001794:Blood Pressure; D005260:Female; D005919:Glomerular Filtration Rate; D006439:Hemodynamics; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000503:physiopathology; D007668:Kidney / Q000502:physiology / Q000503:physiopathology; D008297:Male; D012079:Renal Circulation; D017596:Renal Plasma Flow, Effective
C018524:N,N-dimethylarginine; D001120:Arginine