<i>In situ</i>flow cell platform for examining calcium oxalate and calcium phosphate crystallization on films of basement membrane extract in the presence of urinary ‘inhibitors’

Kuliasha, Cary A.; Rodriguez, Douglas E.; Lovett, Archana C.; Gower, Laurie B.

doi:10.1039/c9ce01587f

Cited by 12 publications

(19 citation statements)

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“…These microscopy-to-omics results pave the way for future experimentation, in which these hypotheses can be systematically tested using highly-controlled microfluidic devices (4,47). For instance, microfluidic testbeds can be used to quantitatively track the intermediate steps of kidney stone formation in real time under high-resolution microscopy, as in a recently published reports (2,3,47). This would allow specific mechanisms and processes controlling kidney stone growth and dissolution to be tested in the context of microbiome community, phylogenetic diversity, functional activity, and biochemistry.…”

Section: Discussionmentioning

confidence: 92%

In Vivo Entombment of Bacteria and Fungi during Calcium Oxalate, Brushite, and Struvite Urolithiasis

et al. 2021

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Background: Human kidney stones form via repeated events of mineral precipitation, partial dissolution and reprecipitation, which are directly analogous to similar processes in other natural and man-made environments where resident microbiomes strongly influence biomineralization. High-resolution microscopy and high-fidelity metagenomic (microscopy-to-omics) analyses, applicable to all forms of biomineralization, have been applied to assemble definitive evidence of in vivo microbiome entombment during urolithiasis. Methods: Stone fragments were collected from a randomly chosen cohort of 20 patients using standard percutaneous nephrolithotomy (PCNL). Fourier transform infrared (FTIR) spectroscopy indicated that 18 of these patients were calcium oxalate (CaOx) stone formers, while one patient each formed brushite and struvite stones. This apportionment is consistent with global stone mineralogy distributions. Stone fragments from 7 of these 20 patients (5 CaOx, 1 brushite and 1 struvite) were thin sectioned and analyzed using brightfield (BF), polarization (POL), confocal, superresolution autofluorescence (SRAF) and Raman techniques. DNA from remaining fragments, grouped according to each of the 20 patients, were analyzed with amplicon sequencing of 16S rRNA gene sequences (V1-V3, V3-V5) and internal transcribed spacer (ITS1, ITS2) regions. Results: Bulk entombed DNA was sequenced from stone fragments in 11 of the 18 CaOx patients, as well as the brushite and struvite patients. These analyses confirmed the presence of an entombed low-diversity community of bacteria and fungi, including Actinobacteria, Bacteroidetes, Firmicutes, Proteobacteria, and Aspergillus niger. Bacterial cells ~1 µm in diameter were also optically observed to be entombed and well-preserved in amorphous hydroxyapatite spherules and fans of needle-like crystals of brushite and struvite. Conclusions: These results indicate a microbiome is entombed during in vivo CaOx stone formation. Similar processes are implied for brushite and struvite stones. This evidence lays the groundwork for future in vitro and in vivo experimentation to determine how the microbiome may actively and/or passively influence kidney stone biomineralization.

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Section: Discussionmentioning

confidence: 92%

In Vivo Entombment of Bacteria and Fungi during Calcium Oxalate, Brushite, and Struvite Urolithiasis

et al. 2021

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“…The polymer used in the PILP process, referred to as the process directing agent, was usually polyaspartate but similar anionic polyelectrolytes were also used [242,243]. Model systems were devised for biomimetic mineralization of collagen sponges [241,244,245] and models of bone [42,241,242,246], tendon [247], dentin [248] and soft tissues [249][250][251][252].…”

Section: Mineralization In the Extracellular Matrix Of Collagenous Hard Tissuesmentioning

confidence: 99%

“…Biomimetic studies of collagen mineralization were also been made with OPN [41,159,[250][251][252][253][254] and interpreted as due to the PILP mechanism. A comparative study showed that collagen mineralization using solutions containing OPN was more homogeneous, rapid and reproducible than with polyaspartate [159].…”

Section: Mineralization In the Extracellular Matrix Of Collagenous Hard Tissuesmentioning

confidence: 99%

“…The solution used to mineralize collagen in the work of Rodriguez et al [41] was designed [112] so that the OPNmix was largely in the form of the equilibrium CaP nanocluster complexes described in Section 4.2. The same OPNmix sample, in a closely similar solution with some minor changes in buffering, was used in subsequent work [159,[251][252][253][254]. Almost certainly these studies were also made with the equilibrium CaP nanocluster complexes.…”

Section: Mineralization In the Extracellular Matrix Of Collagenous Hard Tissuesmentioning

confidence: 99%

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Structural Biology of Calcium Phosphate Nanoclusters Sequestered by Phosphoproteins

et al. 2020

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Biofluids that contain stable calcium phosphate nanoclusters sequestered by phosphopeptides make it possible for soft and hard tissues to co-exist in the same organism with relative ease. The stability diagram of a solution of nanocluster complexes shows how the minimum concentration of phosphopeptide needed for stability increases with pH. In the stable region, amorphous calcium phosphate cannot precipitate. Nevertheless, if the solution is brought into contact with hydroxyapatite, the crystalline phase will grow at the expense of the nanocluster complexes. The physico-chemical principles governing the formation, composition, size, structure, and stability of the complexes are described. Examples are given of complexes formed by casein, osteopontin, and recombinant phosphopeptides. Application of these principles and properties to blood serum, milk, urine, and resting saliva is described to show that under physiological conditions they are in the stable region of their stability diagram and so cannot cause soft tissue calcification. Stimulated saliva, however, is in the metastable region, consistent with its role in tooth remineralization. Destabilization of biofluids, with consequential ill-effects, can occur when there is a failure of homeostasis, such as an increase in pH without a balancing increase in the concentration of sequestering phosphopeptides.

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“…13 Consequently, it appears clear that microfluidics by partially recreating the renal environment and the conditions promoting KS formation can contribute to the understanding of the underlying mechanisms. 22,23,24 Green tea (GT) is one of the most common beverages consumed around the world and has been reported to have potential anti-oxidative effects as well as preventive effects on diseases such as atherosclerosis or Parkinson's disease thanks to its rich content in polyphenols. 19,25,26 Recently, on the basis of clinical observations, the consumption of GT was considered for the treatment of KS, which led to a patent application for the use of its active ingredient, catechins (polyphenolic compounds from GT).…”

Section: Introductionmentioning

confidence: 99%

Investigating CaOx Crystal Formation in the Absence and Presence of Polyphenols under Microfluidic Conditions in Relation with Nephrolithiasis

Rakotozandriny

Bourg

Papp

et al. 2020

Crystal Growth & Design

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Nephrolithiasis is a major health concern in western countries. Herein, we propose a microfluidic based approach to mimic the physical and physicochemical conditions encountered in the collecting duct in a nephron where calcium oxalate (CaOx) precipitation occurs. Our objective is to understand the parameters involved in the formation of such crystals. The microfluidic platform is reversible, allowing interfacial characterizations using scanning electron microscopy imaging and Raman spectroscopy. CaOx crystalline phases and morphologies were studied with respect to hydrodynamics and physicochemical conditions within the channel and at the outlet. While calcium oxalate monohydrate (COM) crystals were dominant within the channel, at the outlet, the crystals were calcium oxalate dihydrate (COD) crystals, which agrees with medical observations. Decreasing the flow rate lowered down the induction time for CaOx formation and enhanced the occurrence of COD crystals. The kinetics of COM crystals growth studied in situ showed two regimes, an initial surface-limited reaction, followed by a transport-limited growth with a dependency of the kinetics on the position of the crystal in the channel. Numerical modeling of CaOx formation in a microchannel using an in-house model considering the chemical reactions involved allowed to confirm the experimental observations on the location of precipitate formation but also to quantitatively match the scaling law related to the early growth of precipitate particles. Finally, the effect of polyphenols naturally found in green tea (GT) on modulating CaOx crystallization was studied in the microfluidic device in different scenarios where GT was initially mixed in solution with the Ca and/or the Ox precursors. The formation of COD crystals rather than COM ones was always predominant; however, depending on the conditions, CaOx crystals of different morphologies could be observed, including COD crystals with an elongated (100) crystalline face and COM crystals with a round-shaped morphology with a concave crystalline face.

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In situflow cell platform for examining calcium oxalate and calcium phosphate crystallization on films of basement membrane extract in the presence of urinary ‘inhibitors’

Abstract: The development of a flow-cell platform is reported that utilizes basement membrane extract as a biologically relevant crystallization substrate to study the effect of urinary inhibitors on the in situ formation of calcium oxalate/phosphate.

Cited by 12 publications

References 44 publications

In Vivo Entombment of Bacteria and Fungi during Calcium Oxalate, Brushite, and Struvite Urolithiasis

In Vivo Entombment of Bacteria and Fungi during Calcium Oxalate, Brushite, and Struvite Urolithiasis

Structural Biology of Calcium Phosphate Nanoclusters Sequestered by Phosphoproteins

Investigating CaOx Crystal Formation in the Absence and Presence of Polyphenols under Microfluidic Conditions in Relation with Nephrolithiasis

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