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This Article Full Text Full Text (PDF) All Versions of this Article: 291/3/F629    most recent 00329.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Saxena, A. B. Articles by Tan, J. C. Search for Related Content PubMed PubMed Citation Articles by Saxena, A. B. Articles by Tan, J. C.

Adaptive hyperfiltration in the aging kidney after contralateral nephrectomy

Division of Nephrology, Stanford University Medical Center, Palo Alto, California

Submitted 15 August 2005 ; accepted in final form 27 February 2006

We examined the magnitude of adaptive hyperfiltration in the remaining kidney of 16 aging (>57 yr) and 16 youthful (<55 yr) individuals who had undergone a contralateral nephrectomy. Healthy volunteers who were youthful (n = 143) or aging (n = 37) provided control values for the binephric condition. One-kidney glomerular filtration rate (GFR; +42%), renal plasma flow (+38%), plasma oncotic pressure (+2.8 mmHg), and mean arterial pressure (+7.0 mmHg) were all higher in youthful uninephric vs. binephric subjects. Corresponding excesses in aging uninephric vs. binephric subjects were by 38 and 36% and 1.4 and 14.0 mmHg, respectively. Modeling of these data revealed that an isolated increase in either the glomerular ultrafiltration coefficient (K_f) by 110% or in the transcapillary hydraulic pressure gradient (P) by 7 mmHg, could account for the observed level of hyperfiltration in youthful uninephric subjects. Corresponding increases for aging uninephric subjects were 61% for K_f and 5 mmHg for P. We conclude that the magnitude of adaptive hyperfiltration is similar in aging to that in youthful uninephric subjects, albeit at a lower absolute GFR level. Isolated increases in either K_f or P or a combination of smaller increases in both can account for the hyperfiltration. Greater adaptive arterial hypertension in aging than youthful uninephric subjects raises the possibility of a disproportionate role for glomerular hypertension and P elevation in aging compared with youthful uninephric subjects. Glomerular hypertension could exacerbate the sclerosing glomerulopathy of senescence and lead to renal insufficiency. We recommend that living donors of a kidney transplantation in or beyond the seventh decade be used with caution.

living kidney donor; uninephrectomy; glomerular filtration