PAH extraction and estimation of plasma flow in diseased human kidneys

Battilana, Carlos A; Zhang, H. P.; Olshen, Richard A.; Wexler, Lewis; Myers, Bryan D.

doi:10.1152/ajprenal.1991.261.4.f726

Cited by 50 publications

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“…The amount of filtrate produced by a given pressure across the glomerular filtration barrier is described by the K f , which is determined by its hydraulic permeability and surface area. culated by dividing PAH clearance by an extraction ratio of 0.9 (34). Plasma oncotic pressure (π A ) was measured using membrane osmometry at pre-donation and early post-donation time points (35).…”

Section: Methodsmentioning

confidence: 99%

Longitudinal study of living kidney donor glomerular dynamics after nephrectomy

Lenihan¹,

Busque²,

Derby³

et al. 2015

J. Clin. Invest.

153

100

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ResultsResponse to donor nephrectomy in healthy humans. Twenty-one subjects underwent clinical, physiological, and radiological assessments immediately before, early after (median, 0.8 years), and late after (median, 6.1 years) (hereafter, pre-donation, early post-donation, and late post-donation) living kidney donation. A morphometric evaluation of glomeruli was performed on renocortical tissue that was obtained by wedge biopsy at the time of donor nephrectomy in 19 subjects. Baseline demographic, physio-BACKGROUND. Over 5,000 living kidney donor nephrectomies are performed annually in the US. While the physiological changes that occur early after nephrectomy are well documented, less is known about the long-term glomerular dynamics in living donors. METHODS.We enrolled 21 adult living kidney donors to undergo detailed long-term clinical, physiological, and radiological evaluation pre-, early post-(median, 0.8 years), and late post-(median, 6.3 years) donation. A morphometric analysis of glomeruli obtained during nephrectomy was performed in 19 subjects.RESULTS. Donors showed parallel increases in single-kidney renal plasma flow (RPF), renocortical volume, and glomerular filtration rate (GFR) early after the procedure, and these changes were sustained through to the late post-donation period. We used mathematical modeling to estimate the glomerular ultrafiltration coefficient (K f ), which also increased early and then remained constant through the late post-donation study. Assuming that the filtration surface area (and hence, K f ) increased in proportion to renocortical volume after donation, we calculated that the 40% elevation in the single-kidney GFR observed after donation could be attributed exclusively to an increase in the K f . The prevalence of hypertension in donors increased from 14% in the early post-donation period to 57% in the late post-donation period. No subjects exhibited elevated levels of albuminuria. CONCLUSIONS.Adaptive hyperfiltration after donor nephrectomy is attributable to hyperperfusion and hypertrophy of the remaining glomeruli. Our findings point away from the development of glomerular hypertension following kidney donation.

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Section: Methodsmentioning

confidence: 99%

Longitudinal study of living kidney donor glomerular dynamics after nephrectomy

Lenihan¹,

Busque²,

Derby³

et al. 2015

J. Clin. Invest.

153

100

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“…RPF was corrected for an assumed para-aminohippuric acid extraction ratio of 0.9, which has been described previously. 22 BP was measured using Dynamap. Plasma oncotic pressure was assayed by membrane osmometry.…”

Section: Assessment Of Kidney Functionmentioning

confidence: 99%

The Association of Predonation Hypertension with Glomerular Function and Number in Older Living Kidney Donors

Lenihan¹,

Busque

Derby³

et al. 2015

Journal of the American Society of Nephrology

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The effect of preexisting hypertension on living donor nephron number has not been established. In this study, we determined the association between preexisting donor hypertension and glomerular number and volume and assessed the effect of predonation hypertension on postdonation BP, adaptive hyperfiltration, and compensatory glomerular hypertrophy. We enrolled 51 living donors to undergo physiologic, morphometric, and radiologic evaluations before and after kidney donation. To estimate the number of functioning glomeruli (N FG ), we divided the whole-kidney ultrafiltration coefficient (K f ) by the single-nephron ultrafiltration coefficient (SNK f ). Ten donors were hypertensive before donation. We found that, in donors ages .50 years old, preexisting hypertension was associated with a reduction in N FG . In a comparison of 10 age-and sex-matched hypertensive and normotensive donors, we observed more marked glomerulopenia in hypertensive donors (N FG per kidney, 359,4996128,929 versus 558,2396205,152; P=0.02). Glomerulopenia was associated with a nonsignificant reduction in GFR in the hypertensive group (89612 versus 95616 ml/min per 1.73 m 2 ). We observed no difference in the corresponding magnitude of postdonation BP, hyperfiltration capacity, or compensatory renocortical hypertrophy between hypertensive and normotensive donors. Nevertheless, we propose that the greater magnitude of glomerulopenia in living kidney donors with preexisting hypertension justifies the need for long-term follow-up studies.

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“…RPF was corrected for an assumed PAH extraction ratio of 0.9, as described elsewhere. 25 Mean arterial pressure was determined by Dynamap, and oncotic pressure in blood was determined by membrane osmometry at the commencement of the clearance study.…”

Section: Physiologic Evaluation Of Gfrmentioning

confidence: 99%

Glomerular Function, Structure, and Number in Renal Allografts from Older Deceased Donors

Tan

Workeneh²,

Busque

et al. 2009

Journal of the American Society of Nephrology

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The 5-yr survival rate of renal allografts is significantly lower for grafts from older deceased donors than from younger deceased donors. For evaluation of the potential contribution of renal senescence in this shortened graft survival, glomerular function and structure were analyzed in allografts from deceased donors older than 55 yr ("aging") or younger than 40 yr ("youthful"). Aging donors had a significantly higher prevalence of sclerotic glomeruli (P Ͻ 0.002), and their nonsclerotic glomeruli tended to be larger, had a larger filtration surface area (P ϭ 0.02), and had a higher single-nephron ultrafiltration coefficient (K f ; P ϭ 0.07), suggesting a compensatory response to functional loss of glomeruli. After serum creatinine reached a stable nadir in the transplant recipients, GFR and its hemodynamic determinants were evaluated and the whole allograft K f was computed. Compared with the allografts from youthful donors, allografts from aging donors exhibited a 32% lower GFR, which was exclusively attributable to a 45% reduction in allograft K f (both P Ͻ 0.001). In addition, the number of functioning glomeruli per allograft was profoundly lower in grafts from aging donors than from youthful donors (3.6 Ϯ 2.1 ϫ 10 5 versus 8.5 Ϯ 3.4 ϫ 10 5 ; P Ͻ 0.01), and this could not be explained by the relatively modest 17% prevalence of global glomerulosclerosis in the aging group. The marked reduction in overall glomerular number in many aging donors may lead to a "remnant kidney" phenomenon, potentially explaining the shorter mean survival of these allografts.

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PAH extraction and estimation of plasma flow in diseased human kidneys

Cited by 50 publications

References 0 publications

Longitudinal study of living kidney donor glomerular dynamics after nephrectomy

Longitudinal study of living kidney donor glomerular dynamics after nephrectomy

The Association of Predonation Hypertension with Glomerular Function and Number in Older Living Kidney Donors

Glomerular Function, Structure, and Number in Renal Allografts from Older Deceased Donors

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