Journal of the American Society of Nephrology, Vol 3, 1371-1377, Copyright © 1993 by American Society of Nephrology

REGULAR ARTICLES

Renal functional reserve in healthy elderly subjects

D Fliser, M Zeier, R Nowack and E Ritz
Department of Internal Medicine, Ruperto-Carola University Heidelberg, Germany.

The increase in GFR after an amino acid (AA) load, the so-called renal functional reserve, is impaired in the aged rat. Whether the renal functional reserve predicts the progression of renal disease in humans is controversial, but it is possible that age-related alterations of renal hemodynamics are relevant for the evolution of renal disease in the elderly. We compared renal hemodynamics before and after an AA infusion in 15 healthy normotensive subjects of young age (seven women, eight men; median age, 26 yr; range, 23 to 32) and in 10 subjects of old age (six women, four men; median age, 70 yr; range, 61 to 82) on normal dietary protein intake. Baseline GFR and effective RPF were measured after 12 h of fasting by the inulin (Cin) and para- aminohippurate (Cpah) steady-state infusion techniques. The renal functional reserve was examined after an overnight AA infusion (7% solution; 83 mL/h). Median basal Cin and Cpah were significantly lower (P < 0.01) in the elderly (102 and 339 mL/min per 1.73 m2) than in the young subjects (122 and 647 mL/min per 1.73 m2), but virtually all GFR values of the elderly were still within the normal range. Median Cin upon infusion of AA was 118 mL/min per 1.73 m2 (range, 98 to 137) in the elderly and 146 (range, 120 to 171) in the young, respectively. Corresponding values of Cpah were 349 mL/min per 1.73 m2 in the elderly versus 689 mL/min per 1.73 m2 in the young. Cin increased significantly (P < 0.01) after the AA load in both young and elderly subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				A. Schwarz, G. Rustien, S. Merkel, J. Radermacher, and H. Haller Decreased renal transplant function after parathyroidectomy Nephrol. Dial. Transplant., February 1, 2007; 22(2): 584 - 591. [Abstract] [Full Text] [PDF]

				M. L. Halperin, S. Cheema-Dhadli, S.-H. Lin, and K. S. Kamel Properties Permitting the Renal Cortex to Be the Oxygen Sensor for the Release of Erythropoietin: Clinical Implications Clin. J. Am. Soc. Nephrol., September 1, 2006; 1(5): 1049 - 1053. [Abstract] [Full Text] [PDF]

				I. Rieu, M. Balage, C. Sornet, C. Giraudet, E. Pujos, J. Grizard, L. Mosoni, and D. Dardevet Leucine supplementation improves muscle protein synthesis in elderly men independently of hyperaminoacidaemia J. Physiol., August 15, 2006; 575(1): 305 - 315. [Abstract] [Full Text] [PDF]

				D. Fliser Ren sanus in corpore sano: the myth of the inexorable decline of renal function with senescence Nephrol. Dial. Transplant., March 1, 2005; 20(3): 482 - 485. [Full Text] [PDF]

				J. T. Kielstein, B. Impraim, S. Simmel, S. M. Bode-Boger, D. Tsikas, J. C. Frolich, M. M. Hoeper, H. Haller, and D. Fliser Cardiovascular Effects of Systemic Nitric Oxide Synthase Inhibition With Asymmetrical Dimethylarginine in Humans Circulation, January 20, 2004; 109(2): 172 - 177. [Abstract] [Full Text] [PDF]

				A. Melk Senescence of renal cells: molecular basis and clinical implications Nephrol. Dial. Transplant., December 1, 2003; 18(12): 2474 - 2478. [Full Text] [PDF]

				J. T. Kielstein, S. M. Bode-Boger, H. Haller, and D. Fliser Functional changes in the ageing kidney: is there a role for asymmetric dimethylarginine? Nephrol. Dial. Transplant., July 1, 2003; 18(7): 1245 - 1248. [Full Text] [PDF]

				J. T. Kielstein, S. M. Bode-Boger, J. C. Frolich, E. Ritz, H. Haller, and D. Fliser Asymmetric Dimethylarginine, Blood Pressure, and Renal Perfusion in Elderly Subjects Circulation, April 15, 2003; 107(14): 1891 - 1895. [Abstract] [Full Text] [PDF]

				C. Sommerer, M. Wiesel, J. Schweitzer-Rothers, E. Ritz, and M. Zeier The living kidney donor: giving life, avoiding harm Nephrol. Dial. Transplant., January 1, 2003; 18(1): 23 - 26. [Full Text] [PDF]

				J. T. Kielstein, R. H. Boger, S. M. Bode-Boger, J. C. Frolich, H. Haller, E. Ritz, and D. Fliser Marked Increase of Asymmetric Dimethylarginine in Patients with Incipient Primary Chronic Renal Disease J. Am. Soc. Nephrol., January 1, 2002; 13(1): 170 - 176. [Abstract] [Full Text] [PDF]

				D. FLISER, R. DIKOW, S. DEMUKAJ, and E. RITZ Opposing Effects of Angiotensin II on Muscle and Renal Blood Flow under Euglycemic Conditions J. Am. Soc. Nephrol., November 1, 2000; 11(11): 2001 - 2006. [Abstract] [Full Text]

				G. Luippold, B. Pech, S. Schneider, H. Osswald, and B. Muhlbauer Age dependency of renal function in CD-1 mice Am J Physiol Renal Physiol, May 1, 2002; 282(5): F886 - F890. [Abstract] [Full Text] [PDF]

Copyright © 2008 by the American Society of Nephrology. Online ISSN: 1533-3450 Print ISSN: 1046-6673