Sieving equations and effective glomerular filtration pressure

Lambert, Pierre-Paul; Verniory, A; Gassee, Jean Pierre; Ficheroulle, Pierre

doi:10.1038/ki.1972.83

Cited by 36 publications

(24 citation statements)

References 24 publications

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“…Two of these, molecular size and the hemodynamic determinants of glomerular filtration rate (GFR) 1 have been recognized for some time (1)(2)(3)(4)(5)(6)(7). The third factor, molecular electrical charge, has only recently been firmly established (8).…”

Section: Introductionmentioning

confidence: 99%

Permselectivity of the glomerular capillary wall. Studies of experimental glomerulonephritis in the rat using dextran sulfate.

Bennett¹,

Glassock²,

Chang³

et al. 1976

J. Clin. Invest.

117

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A B S T R A C T To determine whether the increased filtration of serum proteins after glomerular injury is the consequence of altered electrostatic properties of the glomerular capillary wall, we measured fractional clearances of the anionic polymer, dextran sulfate, in nine Munich-Wistar rats in the early autologous phase of nephrotoxic serum nephritis (NSN). In agreement with previous studies from this laboratory, whole kidney and single nephron glomerular filtration rates were normal in NSN rats despite histological evidence of glomerular injury, and despite a marked reduction in the glomerular capillary ultrafiltration coefficient to approximately one-third of normal. In the companion study (9), it was shown that in NSN rats the mean fractional clearances of neutral dextrans over the range of effective molecular radii from 18 to 42 A were reduced, compared to normal.In contrast, in the present study the mean fractional clearances for dextran sulfate over the same range of molecular radii were significantly greater than those found previously for normal Munich-Wistar rats. The fractional clearance of dextran sulfate molecules of the t Ms. Rasmussen died on 25 June 1975.

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Section: Introductionmentioning

confidence: 99%

Permselectivity of the glomerular capillary wall. Studies of experimental glomerulonephritis in the rat using dextran sulfate.

Bennett¹,

Glassock²,

Chang³

et al. 1976

J. Clin. Invest.

117

View full text Add to dashboard Cite

show abstract

“…This discrepancy is particularly evident in nonglomerular capillaries, as previously reviewed (31,33), and in distributed pore models (20,21,34). In an early pioneering experiment, Lambert et al (21) studied the glomerular sieving of radiolabeled polyvinylpyrrolidone and calculated values for A 0 /⌬x that were up to one order of magnitude larger for the log-normal distributed model than that of the discrete model. In addition, the mean pore radius was lower for the distributed model (21).…”

mentioning

confidence: 92%

“…Often, it has been noted that the volume flow approximated from the diffusive solute transport (A 0 /⌬x) differs from that actually measured experimentally [e.g., the glomerular filtration rate (GFR) for glomerular capillaries]. This discrepancy is particularly evident in nonglomerular capillaries, as previously reviewed (31,33), and in distributed pore models (20,21,34). In an early pioneering experiment, Lambert et al (21) studied the glomerular sieving of radiolabeled polyvinylpyrrolidone and calculated values for A 0 /⌬x that were up to one order of magnitude larger for the log-normal distributed model than that of the discrete model.…”

mentioning

confidence: 93%

“…The classic two-pore model assumes that the transcapillary transport of plasma solutes and water occurs over two distinct porous pathways, small pores and large pores, each having a fixed (discrete) pore radius. In contrast, distributed pore models assume that the pore radii are continuously distributed around a mean radius with a distribution spread [standard deviation (SD)] (1,7,9,11,20,21). In most distributed models, only the small-pore system has been considered, whereas the large-pore pathway has been modeled as an unselective shunt pathway, theoretically allowing free passage of all solutes regardless of molecular size [to our knowledge the only exception is (1), where both the small-pore and large-pore systems are distributed].…”

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confidence: 99%

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A distributed two-pore model: theoretical implications and practical application to the glomerular sieving of Ficoll

Öberg

Rippe

2014

American Journal of Physiology-Renal Physiology

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In the present study, an extended two-pore theory is presented where the porous pathways are continuously distributed according to small- and large-pore mean radii and SDs. Experimental glomerular sieving data for Ficoll were analyzed using the model. In addition, several theoretical findings are presented along with analytic solutions to many of the equations used in distributed pore modeling. The results of the data analysis revealed a small-pore population in the glomerular capillary wall with a mean radius of 36.6 Å having a wide arithmetic SD of ∼5 Å and a large-pore radius of 98.6 Å with an even wider SD of ∼44 Å. The small-pore radius obtained in the analysis was close to that of human serum albumin (35.5 Å). By reanalyzing the data and setting the distribution spread of the model constant, we discovered that a narrow distribution is compensated by an increased mean pore radius and a decreased pore area-to-diffusion length ratio. The wide distribution of pore sizes obtained in the present analysis, even when considering electrostatic hindrance due to the negatively charged barrier, is inconsistent with the high selectivity to proteins typically characterizing the glomerular filtration barrier. We therefore hypothesize that a large portion of the variance in the distribution of pore sizes obtained is due to the molecular "flexibility" of Ficoll, implying that the true variance of the pore system is lower than that obtained using flexible probes. This would also, in part, explain the commonly noted discrepancy between the pore area-to-diffusion length ratio and the filtration coefficient.

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“…The relative size of creatinine is sufficiently small for it to have a high sieving coefficient and, therefore, would have a reduction in filtration in response to a drop in intraglomerular pressure ( Figure 3). 16 Cystatin C, a larger-sized protein, is probably situated at a different location on the sieving function curve and is expected to be influenced less by either an increase or reduction in intraglomerular pressure (Figure 3). 17 Thus, it is conceivable that cystatin C is a better indicator of renal filtration function during perturbations of the RAS from early LV dysfunction or use of RAS blocking agents.…”

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confidence: 99%