The paradoxical role of urinary macromolecules in the aggregation of calcium oxalate: a further plea to increase diuresis in stone metaphylaxis

Baumann, J. M.; Affolter, Beat

doi:10.1007/s00240-016-0863-z

Cited by 11 publications

(12 citation statements)

References 25 publications

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“…On the other hand, numerous organic additives with different ionic entities, including natural macromolecules, synthetic polymers and proteins have been studied from a CC point of view [ 16 , 17 , 18 , 19 ]. The main focus of these studies has been the characterization of the role played by urinary macromolecules, because these are the main organic component of the kidney stone matrix [ 20 ].…”

Section: Introductionmentioning

confidence: 99%

Stabilization of Calcium Oxalate Precursors during the Pre- and Post-Nucleation Stages with Poly(acrylic acid)

et al. 2021

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In this work, calcium oxalate (CaOx) precursors were stabilized by poly(acrylic acid) (PAA) as an additive under in vitro crystallization assays involving the formation of pre-nucleation clusters of CaOx via a non-classical crystallization (NCC) pathway. The in vitro crystallization of CaOx was carried out in the presence of 10, 50 and 100 mg/L PAA by using automatic calcium potentiometric titration experiments at a constant pH of 6.7 at 20 °C. The results confirmed the successful stabilization of amorphous calcium oxalate II and III (ACOII and ACO III) nanoparticles formed after PNC in the presence of PAA and suggest the participation and stabilization of polymer-induced liquid-precursor (PILP) in the presence of PAA. We demonstrated that PAA stabilizes CaOx precursors with size in the range of 20–400 nm. PAA additive plays a key role in the in vitro crystallization of CaOx stabilizing multi-ion complexes in the pre-nucleation stage, thereby delaying the nucleation of ACO nanoparticles. Indeed, PAA additive favors the formation of more hydrated and soluble phase of ACO nanoparticles that are bound by electrostatic interactions to carboxylic acid groups of PAA during the post-nucleation stage. These findings may help to a better understanding of the pathological mineralization resulting in urolithiasis in mammals.

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Section: Introductionmentioning

confidence: 99%

Stabilization of Calcium Oxalate Precursors during the Pre- and Post-Nucleation Stages with Poly(acrylic acid)

et al. 2021

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“…AGN also occurred in all UM solutions which were obtained either by dialysis of urine by a hemofilter procedure [28] or by Ca phosphate precipitation as described below. On the other hand, in 14 of 15 freshly voided urine specimens of HC even after Ox addition of 1.5 mM with massive crystal formation no AGN could be observed [32]. However, after the addition of 0.05 mg/mL HAP and repeating the crystallization test the inhibition of AGN was abolished in 8 of the 14 urine specimens.…”

Section: Experimental Investigation For a Better Understanding Of mentioning

confidence: 99%

“…Afterwards the precipitates were dissolved at pH 5.0 and after adaption of Ca + , Na, and pH to urinary values CaOx crystallization tests were performed. Maximal OD decreases observed in these experiments after the end of Ox titration are compared in Figure 2 with those measured in urine and in AS with and without previous addition of HAP [32].…”

Section: Experimental Investigation For a Better Understanding Of mentioning

confidence: 99%

Prevention of Calcium Nephrolithiasis: The Influence of Diuresis on Calcium Oxalate Crystallization in Urine

Baumann

Casella

2019

Advances in Preventive Medicine

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A high fluid intake is still the most evidence-based measure for the prevention of idiopathic stone disease. The recommendation of current guidelines on urolithiasis to increase diuresis to 2–2.5 L/day is mainly based on a single clinical study. The present paper shows the influence of diuresis on calcium oxalate (CaOx) crystallization and especially aggregation (AGN) which can explain the initial development of Ca stones on papillary calcifications as well as stone growth in the renal pelvic system. Diuresis determines the urinary transit time (UT) through the kidney and together with the afflux of Ca and Ox the state of urinary saturation with respect to CaOx being the most frequent stone mineral. High supersaturation inducing crystallization during UT and a high urinary ion concentration interfering with the inhibition of crystal AGN by urinary macromolecules seem to be critical parameters for stone formation. Using data from the literature the influence of diuresis on these parameters is evaluated for short-term recurrent stone formers (RSF), idiopathic stone patients, and healthy controls, the latter two collectives with and without excessive oxalate ingestion. This investigation suggests that a diuresis of 2 L/day may protect from stone formation even after dietary Ox excesses and in RSF. However, in RSF with a continuously high Ca and Ox afflux into urine a permanent high diuresis is required which is difficult to sustain over 24 hours.

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“…To prepare cHAP, commercially available HAP crystals (0.05 mg/ml) were incubated at 37° during at least 30 min in one portion each of 15 urines from healthy persons [46]. After centrifugation and discharge of the supernatant, the crystals were suspended in a second portion of the same urine.…”

Section: Caox Agn In the Presence Of Hydroxyapatite (Hap) A Possiblementioning

confidence: 99%

“…Under the special conditions of our experiments, albumin seems to be an ideal substance to mimic UM effects. Adsorption on surfaces favors self-AGN of UMs as demonstrated with respect to albumin and thus can turn inhibitors to promoters of AGN [46]. Ca phosphates are excellent substrates for UM adsorption [5].…”

Section: Caox Agn In the Presence Of Hydroxyapatite (Hap) A Possiblementioning

confidence: 99%

The Way from Renal Calcifications and Urinary Crystals to Kidney Stones: An Important Aspect in the Pathogenesis of Calcium Nephrolithiasis

Baumann¹

2018

Pathophysiology - Altered Physiological States

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The formation of calcium (Ca) stones occurs in an initial phase by fixed growth on kidney calcifications consisting either of intratubular crystal accumulations protruding in renal calices (Randall's plugs) or of interstitial hydroxyapatite deposits (Randall's plaques) broken through the covering epithelial layers. Crystal aggregation (AGN) seems to be responsible for stone growth during crystalluria. This chapter reports on new aspects of the AGN of calcium oxalate being the most frequent stone compound and tries to explain why despite the widespread occurrence of kidney calcifications and crystalluria not everybody forms stones. Urinary crystals normally are protected from AGN by coats of urinary macromolecules (UMs) which by their identical electronegative charge create zones of electrostatic repulsion. At high urinary concentration or ionic strength respectively, these zones are compressed and can be bridged by self-aggregated UMs. Self-AGN occurs in concentrated urine by the adsorption of UMs on free surfaces like Randall's plugs or plaques. High oxalate excretion and high urine concentration favoring intratubular crystal accumulation, breaking of epithelial layers on Randall's plaques and self-AGN of UMs are most deleterious factors in Ca stone formation and have to be avoided by stone metaphylaxis.

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The paradoxical role of urinary macromolecules in the aggregation of calcium oxalate: a further plea to increase diuresis in stone metaphylaxis

Cited by 11 publications

References 25 publications

Stabilization of Calcium Oxalate Precursors during the Pre- and Post-Nucleation Stages with Poly(acrylic acid)

Stabilization of Calcium Oxalate Precursors during the Pre- and Post-Nucleation Stages with Poly(acrylic acid)

Prevention of Calcium Nephrolithiasis: The Influence of Diuresis on Calcium Oxalate Crystallization in Urine

The Way from Renal Calcifications and Urinary Crystals to Kidney Stones: An Important Aspect in the Pathogenesis of Calcium Nephrolithiasis

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