Process Of Stone Formation Research Articles

Ab Initio Molecular Dynamics Simulations of Phosphocholine Interactions with a Calcium Oxalate Dihydrate (110) Surface.

We use ab initio modeling (CASTEP) to help elucidate the crystallization phenomena and chemistry behind kidney stone composition and formation. To explore the stone formation process, we have constructed a surface model of calcium oxalate dihydrate-the mineral most commonly found in patients with hypercalciuria and modeled stone growth, by simulating further calcium oxalate adsorption onto the surface (-7.446 eV, -0.065 eV/atom). Furthermore, urine analysis of kidney stone patients has previously revealed that their urine contains higher concentrations of phospholipids compared to healthy individuals. Therefore, to investigate the interactions between urinary macromolecules and the growing crystal surfaces at an atomic level, we have performed ab initio molecular dynamics simulations of phosphocholine adsorption on calcium oxalate surfaces. We have shown that the phosphocholine headgroups become entrapped within the growing crystal and the lowest energy structures (-18.008 eV, -0.0396 eV/atom) are those where the calcium oxalate dihydrate surfaces have become disrupted, with reorganization of their crystallographic structure. Urinary calculi (kidney stones) are a common ailment affecting around 10% of the world's population and resulting in nearly 90,000 finished consultant episodes (FCE) each year in the United Kingdom [Hospital Episode Statistics, Admitted Patient Care-England, 2011-12 NHS Digital, 2021-2022. https://digital.nhs.uk/data-and-information/publications/statistical/hospital-admitted-patient-care-activity/hospital-episode-statistics-admitted-patient-care-england-2011-12].

The Role of Metal Nanoparticles in the Pathogenesis of Stone Formation.

The process of stone formation in the human body remains incompletely understood, which requires clinical and laboratory studies and the formulation of a new endogenous, nanotechnological concept of the mechanism of origin and formation of crystallization centers. Previously, the mechanism of sialolithiasis was considered a congenital disease associated with the pathology of the ducts in the structure of the glands themselves. To date, such morphological changes of congenital nature can be considered from the position of the intrauterine formation of endogenous bacterial infections complicated by the migration of antigenic structures initiating the formation of crystallization centers. The present work is devoted to the study of the morphology and composition of stones obtained as a result of surgical interventions for sialolithiasis. Presumably, nanoparticles of metals and other chemical compounds can be structural components of crystallization centers or incorporated into the conditions of chronic endogenous inflammation and the composition of antigenic structures, in complexes with protein and bacterial components. X-ray microtomography, X-ray fluorescence analysis, scanning transmission electron microscopy and microanalysis, mass spectrometry, and Raman spectroscopy were used to study the pathogenesis of stone formation. Immunoglobulins (Igs) of classes A and G, as well as nanoparticles of metals Pb, Fe, Cr, and Mo, were found in the internal structure of the stones. The complex of antigenic structures was an ovoid calcified layered matrix of polyvid microbial biofilms, with the inclusion of metal nanoparticles and chemical elements, as well as immunoglobulins. The obtained results of clinical and laboratory studies allow us to broaden the view on the pathogenesis of stone formation and suggest that the occurrence of the calcification of antigenic structures may be associated with the formation of IgG4-associated disease.

The key role of major and trace elements in the formation of five common urinary stones

BackgroundUrolithiasis has emerged as a global affliction, recognized as one of the most excruciating medical issues. The elemental composition of stones provides crucial information, aiding in understanding the causes, mechanisms, and individual variations in stone formation. By understanding the interactions between elements in various types of stones and exploring the key role of elements in stone formation, insights are provided for the prevention and treatment of urinary stone disease.MethodsThis study collected urinary stone samples from 80 patients in Beijing. The chemical compositions of urinary stones were identified using an infrared spectrometer. The concentrations of major and trace elements in the urinary stones were determined using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), respectively. The data were processed using correlation analysis and Principal Component Analysis (PCA) methods.ResultsUrinary stones are categorized into five types: the calcium oxalate (CO) stone, carbonate apatite (CA) stone, uric acid (UA) stone, mixed CO and CA stone, and mixed CO and UA stone. Ca is the predominant element, with an average content ranging from 2.64 to 27.68% across the five stone groups. Based on geochemical analysis, the high-content elements follow this order: Ca > Mg > Na > K > Zn > Sr. Correlation analysis and PCA suggested significant variations in the interactions between elements for different types of urinary stones. Trace elements with charges and ionic structures similar to Ca may substitute for Ca during the process of stone formation, such as Sr and Pb affecting the Ca in most stone types except mixed stone types. Moreover, the Mg, Zn and Ba can substitute for Ca in the mixed stone types, showing element behavior dependents on the stone types.ConclusionThis study primarily reveals distinct elemental features associated with five types of urinary stones. Additionally, the analysis of these elements indicates that substitutions of trace elements with charges and ion structures similar to Ca (such as Sr and Pb) impact most stone types. This suggests a dependence of stone composition on elemental behavior. The findings of this study will enhance our ability to address the challenges posed by urinary stones to global health and improve the precision of interventions for individuals with different stone compositions.

О воздействии терапии хронической сердечной недостаточности на литогенные свойства мочи.

Introduction. In cardiology practice, a considerable number of drugs, having evident metabolic effects, are used, including those that impact on the process of stone formation. The Research Aim. To study the effects of cardiotropic drugs that can affect the likelihood of recurrence of nephrolithiasis. Materials and Methods. The retrospective study was performed on 49 patients suffering from recurrent urate nephrolithiasis and drug-compensated chronic heart failure, who were treated in branch No. N.N. Burdenko” MO in 2018-2022. Two groups of patients were examined, according to the scheme of cardiotropic therapy: group I - losartan, bisoprolol, atorvastatin, clopidogrel, spironolactone, dapagliflozin (n=25); Group II - enalapril, bisoprolol, atorvastatin, acetylsalicylic acid, spironolactone (n=24). Duration of observation is 3 months. Results. When using the scheme based on losartan and dapagliflozin (Group I), a significant decrease in the serum concentration of uric acid and a simultaneous increase in its renal excretion against the background of increased diuresis and a decrease in urine acidity were revealed compared with patients who received the scheme based on enalapril (II group). There were no significant differences between the groups in terms of the risk of decompensation of chronic heart failure, recurrence of stone formation and the frequency of episodes of urinary tract infection. Conclusion. Сardiotropic therapy has a significant effect on the properties of urine in patients with nephrolithiasis. None of the approaches studied demonstrated either overwhelming advantages or disqualifying disadvantages. Both of them have the right to exist. Despite the uricosuric effect, the use of dapagliflozin for the treatment of chronic heart failure in patients with urate nephrolithiasis was not accompanied by an increase in the frequency of recurrence of stone formation.

Метаболические факторы риска и формирование мочевых камней. Исследование VIII: Литогенные свойства кислотности мочи у мужчин и женщин.

Introduction. Urine acidity is an important factor that can actively modulate the process of stone formation in the kidneys, which allows using this indicator to use this indicator to assess the risk urinary stone formation and control the result of anti-relapse treatment in patients with urolithiasis (UL). There are gender differences in the prevalence of UL, which may be related to differences in urine acidity. In this study, the effect of varying degrees of pH urine on metabolic parameters and the frequency of detection of urinary stones of various chemical compositions was studied in men and women with UL. Materials and methods. We examined 982 patients with ICD (439 men and 543 women aged 18 to 79 years). To assess the lithogenic activity of uricosuria in men and women with UL, the pH values of morning urine were distributed in ascending order and divided into several groups. In each of the ranges, the percentage distribution of types of urinary stones and biochemical parameters of urine and blood were determined. Results. At urine pH of 5.1-6.5, men have higher calciuria and are more prone to oxalate stone formation, which is 1.5-2.2 times more active in them than in women (p <0.05). In contrast to men, the urinary pH level of women had a greater effect on the frequency of detection of oxalate stones, which decreased by 75.9% with a urine pH of 5.5-5.9 and higher, and was accompanied by a 33.3% decrease in calciuria (p <0.05). Uric acid lithogenesis was more dependent on changes in the pH of urine than on the activity of urocosuria. The frequency of formation of uric acid stones was inversely correlated with the pH of urine in men (r=-0.833, p=0.0102) and women (r=-0.929, p=0.0009). With a decrease in the pH of urine below 6.0, the incidence of uric acid stones in women increased by 5.76 times (p<0.0001), and in men by 1.91 times (p=0.0087). Active phosphate lithogenesis in women did not depend on the level of phosphate excretion, which was 25.5-39.7% lower than in men and progressively decreased with increasing urine pH values (p<0.00029). When the urine pH is higher than 5.9, women have a significantly increased risk of developing calculi from carbonatapatite compared to men (p=0.0005). Struvite lithogenesis increased with urine alkalinization and was more pronounced in women than in men (p=0.043). Comparison of age groups did not reveal any differences in the acidity of morning urine between men and women, however, in contrast to men, a noticeable predominance of the proportion of women with carbonatapatite stones was observed in the groups of patients older than 49 years. Conclusion. Shifts in the pH of urine can change the nature and direction of lithogenesis in men and women in different ways and are not always associated with the excretion of certain metabolic factors involved in stone formation. Gender features of the lithogenesis of various types of stones in conditions of different acidity of urine should be taken into account when conducting personalized metaphylaxis of urolithiasis.

Кристаллообразующая активность мочи и методы ее измерения.

ntroduction. Diagnosis and determination of treatment tactics in patients with urolithiasis are based on determining the causes of lithogenesis. At the moment, the standard of examination in patients at high risk of recurrence of urolithiasis is the detection of metabolic disorders based on the results of a biochemical analysis of blood and daily urine, as well as an assessment of the chemical composition of the urinary stone. The violations determined using this approach are a manifestation of the physico-chemical processes of stone formation, the assessment of which is currently practically not performed by urologists, due to the lack of simple diagnostic methods and tools. Materials and methods. The review was conducted on the basis of data published in PubMed databases (https://www.ncbi.nlm.nih.gov/pubmed) and Scientific Electronic Library еLibrary.ru (https://elibrary.ru/), and was limited only to articles in scientific peer-reviewed journals. The search was devoted to the study of the crystal-forming activity of urine, factors affecting the lithogenic properties of urine, as well as methods for assessing the risk of stone formation in the most common metabolic types of urolithiasis. We found 189 sources no older than 10 years (published after 2012) that were relevant to the topic of the review. Conference abstracts, short messages, duplicate publications wereexcluded from them. After that, based on the relevance of the data, reliability of sources, impact factors of journals and the sequence of presentation of the material in the manuscript, 41 articles were selected directly for citation in the review. Also, when writing the review, original articles published before 2012 were used. Results. The analyzed literature sources demonstrated a large number of methods for determining the crystallization properties of urine. However, none of them, in view of the complexity, as well as the ambiguity of the results obtained, have not been widely introduced into clinical practice. In view of this, it is required to develop a simple and informative method for diagnosing the crystal-forming properties of urine, which will increase the percentage of non-reactive urolithiasis. Conclusions. The methods available to doctors for determining the crystal-forming properties of urine are extremely laborious. The development of an easy-to-use and sufficiently accurate real-time determination of the crystallization and anti-crystallization properties of urine, will significantly improve the diagnosis, treatment and metaphylaxis of urolithiasis.

Kidney stone matrix proteins: Role in stone formation.

Stone formation is induced by an increased level of urine crystallization promoters and reduced levels of its inhibitors. Crystallization inhibitors include citrate, magnesium, zinc, and organic compounds such as glycosaminoglycans. In the urine, there are various proteins, such as uromodulin (Tamm-Horsfall protein), calgranulin, osteopontin, bikunin, and nephrocalcin, that are present in the stone matrix. The presence of several carboxyl groups in these macromolecules reduces calcium oxalate monohydrate crystal adhesion to the urinary epithelium and could potentially protect against lithiasis. Proteins are the most abundant component of kidney stone matrix, and their presence may reflect the process of stone formation. Many recent studies have explored the proteomics of urinary stones. Among the stone matrix proteins, the most frequently identified were uromodulin, S100 proteins (calgranulins A and B), osteopontin, and several other proteins typically engaged in inflammation and immune response. The normal level and structure of these macromolecules may constitute protection against calcium salt formation. Paradoxically, most of them may act as both promoters and inhibitors depending on circumstances. Many of these proteins have other functions in modulating oxidative stress, immune function, and inflammation that could also influence stone formation. Yet, the role of these kidney stone matrix proteins needs to be established through more studies comparing urinary stone proteomics between stone formers and non-stone formers.

Quantitative analysis of calcium oxalate monohydrate and dihydrate for elucidating the formation mechanism of calcium oxalate kidney stones.

We sought to identify and quantitatively analyze calcium oxalate (CaOx) kidney stones on the order of micrometers, with a focus on the quantitative identification of calcium oxalate monohydrate (COM) and dihydrate (COD). We performed Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (PXRD), and microfocus X-ray computed tomography measurements (microfocus X-ray CT) and compared their results. An extended analysis of the FTIR spectrum focusing on the 780 cm-1 peak made it possible to achieve a reliable analysis of the COM/COD ratio. We succeeded in the quantitative analysis of COM/COD in 50-μm2 areas by applying microscopic FTIR for thin sections of kidney stones, and by applying microfocus X-ray CT system for bulk samples. The analysis results based on the PXRD measurements with micro-sampling, the microscopic FTIR analysis of thin sections, and the microfocus X-ray CT system observation of a bulk kidney stone sample showed roughly consistent results, indicating that all three methods can be used complementarily. This quantitative analysis method evaluates the detailed CaOx composition on the preserved stone surface and provides information on the stone formation processes. This information clarifies where and which crystal phase nucleates, how the crystals grow, and how the transition from the metastable phase to the stable phase proceeds. The phase transition affects the growth rate and hardness of kidney stones and thus provides crucial clues to the kidney stone formation process.

In silico analysis of Potential Phytochemical Constituents of Orthosiphon stamineus as Significant Inhibitors Against Urolithiasis

Naturally occurring bioactives from plant sources have played a significant role in developing multi-targeted drugs towards treatment of various human ailments. Urolithiasis is the process of stone formation in the kidney, urinary tract or in bladder. It occurs to 1 in 20 people at different phases of their life causing pain in the abdomen, flank or groin and bloody urine at times. The current study focuses on pythochemical activity of Orthosiphon stamineus(Java tea) that can act against kidney stone. The target proteins responsible for stone formation was identified through literature search and the three dimensional structures available was retrieved from Protein Data Bank and structures unavailable was modelled through computational methods. These proteins were docked against the phytochemicals and certain synthetic compounds which are commercially used for Urolithiasis. The best docked compounds and their interaction have been studied and it was identified that when compared to the synthetic compounds, there is high Volume 110|10-12 competence for phytochemicals in binding to the target proteins which suggests that these compounds can be used further for the process of designing a drug effectively against urolithiasis.

ПОТЕНЦИАЛЬНЫЕ МАРКЕРЫ РЕЦИДИВИРОВАНИЯ МОЧЕКАМЕННОЙ БОЛЕЗНИ И РОЛЬ ИНГИБИТОРОВ КАМНЕОБРАЗОВАНИЯ ПРИ РЕЦИДИВИРУЮЩЕМ КАЛЬЦИЙ-ОКСАЛАТНОМ НЕФРОЛИТИАЗЕ

Nowadays urolithiasis (nephrolithiasis) is a common disease, which treatment is a serious task of health care ser- vices not only in Russia, but throughout the world. At the same time, stones of a calcium-oxalate nature are the most common stones in patients with this pathology – in about 70-80% of cases. It is also worth noting that this disease not only has rather painful manifestations, and its treatment requires large financial costs, but also has a complex multi- factorial multistage pathogenesis, understanding the mechanisms of which can provide a key to the development of the most successful therapy. Pathogenesis itself consists of several stages, such as nucleation with the formation of a crystallization center, crystal growth, aggregation and their attachment to the surface of epithelial cells.
 It is known that the human body contains various substances that affect the processes of stone formation. Thus, stone formation promoters facilitate their crystallization, and inhibitors prevent it. There is a delicate balance between promoters and inhibitors, and their imbalance is often a decisive factor in pathogenesis. By their chemical nature, inhibitors can be both inorganic and organic (proteins, glycosaminoglycans) substances. The latter are especially attracting attention, since at various concentrations they can act as both inhibitors and promoters of stone formation. To fully understand the mechanisms of calcium oxalate stone formation, this review analyzes current data on inhibitors of recurrent nephrolithiasis and their role in the pathophysiology of the process of renal stone formation.

The Risk of the Development and Relationship of Kidney Stone Disease and Osteoporosis (Literature review)

Urinary stone disease (USD) is a common pathology with the formation of calculi in the kidneys, ureter, and bladder. Besides the family history, hyperparathyroidism, hypo- and hypervitaminosis of vitamin D, hypercalciuria, and hyperoxaluria are the high risk factors for USD development. This is due primarily to the activation of bone resorption with increased hypercalciuria. It is known that in the urine of every person there is a small amount of urea, inorganic salts, uric acid, creatinine and other substances. The main reason for the formation of calculi is a certain metabolic disorder, which leads to the formation of insoluble salts from which stones are formed – urates, phosphates, oxalates, etc. One of the unsolved problems in the metaphylaxis of USD is the treatment and prevention of osteoporosis which is comorbid with it, since calcium and vitamin D preparations are widely used for the prevention and treatment of osteoporosis. Osteoporosis and arterial calcification often coincide in the nature of the manifestation, which indicates an imbalance in the redistribution of calcium with a predominant direction in the vascular the wall. Vitamin K2 deficiency is closely related to the process of vascular calcification. In the cardiovascular system, with the use of vitamin K antagonists or vitamin K deficiency, calcification of the endothelium of blood vessels occurs. The effect of osteocalcin protein on stone formation processes is controversial. For example, some researchers have found that high serum level of Glaprotein is associated with a lower risk of kidney stones. Based on the results of a daily urinalysis study, the EAU Guidelines (2022) updated the recommendations on metaphylactic USD regarding the benefit/harm of additional calcium and vitamin D use in patients with nephrolithiasis depending on the type of crystalluria. The absence of recommendations for the management of patients with combined pathologies (USD, osteoporosis, cardiovascular diseases) prompts a comprehensive assessment of common risk factors, as well as the formation of programs and algorithms for early diagnosis and the development of recommendations for the prevention and avoidance of complications. Based on the literature analysis, it was established that today the issue of choosing the optimal management for diagnosis and treatment of USD and osteoporosis is still very controversial and ambiguous. There is a necessity for detailed study of this problem, the development of a complex differentiated approach to diagnosis and treatment of patients.

Urinary stone composition in Germany: results from 45,783 stone analyses

PurposeStone composition can provide valuable information for the diagnosis, treatment and recurrence prevention of urolithiasis. The aim of this study was to evaluate the distribution of urinary stone components and the impact of different crystal forms according to gender and age of patients in Germany.MethodsA total of 45,783 urinary stones submitted from 32,512 men and 13,271 women between January 2007 and December 2020 were analyzed by infrared spectroscopy. Only the first calculus obtained per patient was included in the analysis.ResultsThe most common main stone component was calcium oxalate (CaOx) (71.4%), followed by carbonate apatite (CA) (10.2%) and uric acid (UA) (8.3%). Struvite (2.1%), brushite (1.3%), protein (0.5%) and cystine (0.4%) stones were only rarely diagnosed. CaOx (75%) and UA stones (81%) were more frequently obtained from men than women (p < 0.001). Weddellite (COD) and uric acid dihydrate (UAD) were more common in younger ages than whewellite (COM) and anhydrous uric acid (UAA), respectively, in both men and women. The ratios of COM-to-COD and UAA-to-UAD calculi were approximately 4:1 and 8:1, respectively. The peak of stone occurrence was between the ages of 40 and 59 years.ConclusionStone composition is strongly associated with gender and age. The peak incidence of calculi in both women and men was in the most active phase of their working life. The distinction between different crystal forms could provide clues to the activity and mechanisms of lithogenesis. Further research is needed in understanding the causative factors and the process of stone formation.

Aspects of management of patients with cholelithiasis: clinical example

Gallstone disease (GSD) is currently one of the most common diseases of the gastrointestinal tract, especially among people of working age, and has a clear tendency to increase and expand the age range towards rejuvenation. To date, the possible links in the pathogenesis of cholelithiasis have been well studied and described, risk factors and clinical manifestations have been studied and described, among which the asymptomatic course of cholelithiasis, which is often noted at the first latent stage of the disease, is important. It is at this stage that preventive conservative treatment allows most patients to avoid stone formation. However, after ascertaining biliary sludge, therapeutic correction is not carried out. Among the drugs used as oral litholytic therapy, ursodeoxycholic acid (UDCA) is used, which is effective for predominantly cholesterol (X-ray negative) calculi up to 15–18 mm in size or biliary sludge in the form of putty bile. It is known that UDCA changes the ratio of cholesterol/bile acids in bile, which contributes to the mobilization of cholesterol from gallstones and cause their partial or complete dissolution, and prevent the formation of new calculi. At the same time, the use of oral litholytic therapy is also possible at stage 2 of cholelithiasis with asymptomatic or rare attacks of biliary colic, the absence of violations of the patency of the extrahepatic bile ducts, and also if the patient does not agree to cholecystectomy in order to stabilize the process of stone formation. This article presents a review of the literature on the etiopathogenetic, clinical features of cholelithiasis, as well as the treatment of cholelithiasis, primarily with an emphasis on the prevention of this disease. An analysis of a clinical case is given with a discussion of rational pharmacocorrection in cholelithiasis.

Trigonelline prevents kidney stone formation processes by inhibiting calcium oxalate crystallization, growth and crystal-cell adhesion, and downregulating crystal receptors

Trigonelline is the second most abundant bioactive alkaloid found in coffee. It is classified as a phytoestrogen with similar structure as of estradiol and exhibits an estrogenic effect. A previous study has reported that fenugreek seed extract rich with trigonelline can reduce renal crystal deposition in ethylene glycol-induced nephrolithiatic rats. However, direct evidence of such anti-lithogenic effects of trigonelline and underlying mechanisms have not previously been reported. Our study therefore addressed the protective effects and mechanisms of trigonelline against kidney stone-forming processes using crystallization, crystal growth, aggregation and crystal-cell adhesion assays. Also, proteomics was applied to identify changes in receptors for calcium oxalate monohydrate (COM), the most common stone-forming crystal, on apical membranes of trigonelline-treated renal tubular cells. The analyses revealed that trigonelline significantly reduced COM crystal size, number and mass during crystallization. Additionally, trigonelline dose-dependently inhibited crystal growth and crystal-cell adhesion, but did not affect crystal aggregation. Mass spectrometric protein identification showed the smaller number of COM crystal receptors on apical membranes of the trigonelline-treated cells. Western blotting confirmed the decreased levels of some of these crystal receptors by trigonelline. These data highlight the protective mechanisms of trigonelline against kidney stone development by inhibiting COM crystallization, crystal growth and crystal-cell adhesion via downregulation of the crystal receptors on apical membranes of renal tubular cells.

Plants Used in Mexican Traditional Medicine for the Management of Urolithiasis: A Review of Preclinical Evidence, Bioactive Compounds, and Molecular Mechanisms.

Urolithiasis (UL) involves the formation of stones in different parts of the urinary tract. UL is a health problem, and its prevalence has increased considerably in developing countries. Several regions use plants in traditional medicine as an alternative in the treatment or prevention of UL. Mexico has known about the role of traditional medicine in the management of urinary stones. Mexican traditional medicine uses plants such as Argemone mexicana L., Berberis trifoliata Hartw. ex Lindl., Costus mexicanus Liebm, Chenopodium album L., Ammi visnaga (L.) Lam., Eysenhardtia polystachya (Ortega) Sarg., Selaginella lepidophylla (Hook. & Grev.) Spring, and Taraxacum officinale L. These plants contain different bioactive compounds, including polyphenols, flavonoids, phytosterols, saponins, furanochromones, alkaloids, and terpenoids, which could be effective in preventing the process of stone formation. Evidence suggests that their beneficial effects might be associated with litholytic, antispasmodic, and diuretic activities, as well as an inhibitory effect on crystallization, nucleation, and aggregation of crystals. The molecular mechanisms involving these effects could be related to antioxidant, anti-inflammatory, and antimicrobial properties. Thus, the review aims to summarize the preclinical evidence, bioactive compounds, and molecular mechanisms of the plants used in Mexican traditional medicine for the management of UL.

Systematic analysis of modulating activities of native human urinary Tamm-Horsfall protein on calcium oxalate crystallization, growth, aggregation, crystal-cell adhesion and invasion through extracellular matrix

Functions of Tamm-Horsfall protein (THP), the most abundant human urinary protein, have been studied for decades. However, its precise roles in kidney stone formation remain controversial. In this study, we aimed to clarify the roles of native human urinary THP in calcium oxalate monohydrate (COM) kidney stone formation. THP was purified from the human urine by adsorption method using diatomaceous earth (DE). Its effects on stone formation processes, including COM crystallization, crystal growth, aggregation, crystal-cell adhesion and invasion through extracellular matrix (ECM), were examined. SDS-PAGE and Western blotting confirmed that DE adsorption yielded 84.9% purity of the native THP isolated from the human urine. Systematic analyses revealed that THP (at 0.4–40 μg/ml) concentration-dependently reduced COM crystal size but did not affect the crystal mass during initial crystallization. At later steps, THP concentration-dependently inhibited COM crystal growth and aggregation, and prevented crystal-cell adhesion only at 40 μg/ml. However, THP did not affect crystal invasion through the ECM. Sequence analysis revealed two large calcium-binding domains (residues 65–107 and 108–149) and three small oxalate-binding domains (residues 199–207, 361–368 and 601–609) in human THP. Immunofluorescence study confirmed the binding of THP to COM crystals. Analyses for calcium-affinity and/or oxalate-affinity demonstrated that THP exerted a high affinity with only calcium, not oxalate. Functional validation revealed that saturation of THP with calcium, not with oxalate, could abolish the inhibitory effects of THP on COM crystal growth, aggregation and crystal-cell adhesion. These data highlight the inhibitory roles of the native human urinary THP in COM crystal growth, aggregation and crystal-cell adhesion, which are the important processes for kidney stone formation. Such inhibitory effects of THP are most likely mediated via its high affinity with calcium ions.

Hyaluronic acid promotes calcium oxalate crystal growth, crystal-cell adhesion, and crystal invasion through extracellular matrix

Hyaluronic acid (HA), a macromolecule in glycosaminoglycans family, is normally excreted into the urine with a small amount, but with much greater level in the urine from stone patients (formers). However, its precise roles in kidney stone pathogenesis remained unclear. This study examined its roles in calcium oxalate (CaOx) kidney stone formation processes, including neocrystallization, crystal growth, adhesion, internalization, aggregation and invasion. The results showed that HA (1, 10, 100, 1000, or 10,000 ng/ml) did not affect CaOx neocrystallization, aggregation, and internalization into MDCK distal renal tubular cells. However, HA significantly promoted CaOx crystal growth (at 10–10,000 ng/ml), adhesion onto renal tubular cells (at 1000–10,000 ng/ml), and invasion through extracellular matrix (ECM) (at 1–10,000 ng/ml). Analysis of the plasminogen sequence revealed six sites with the HA-binding motif “B(X7)B" that explained the HA ability to trigger the plasminogen-plasmin system required for crystal invasion. In summary, our systematic analysis highlights the promoting effects of HA on CaOx crystal growth, crystal-cell adhesion and invasion through the ECM. These effects of HA may explain its high level in the stone patients' urine, thereby promoting the stone formation.

Discovering inhibitor molecules for pathological crystallization of CaOx kidney stones from natural extracts of medical herbs

Ethnopharmacological relevanceKidney stones is one of the common diseases of the urinary system. The primary cause of kidney stone formation is the thermodynamic supersaturation of lithogenic solutes in urine, which desaturates by nucleation, crystal growth and aggregation of minerals and salts, mainly Calcium oxalate (CaOx). One of the potential therapies is to develop drug molecules to inhibit or prevent CaOx crystallization in urine. Traditional Chinese medicines (TCMs) provided an efficient approach for the treatment of kidney stones with a specialized-designed recipe of medicinal herbs. But the action details of these herbs were poorly understood due to their complex components, and whether the effective constituents of herbs have an inhibitory effect on the process of stone formation has not been evaluated. Aim of the studyThis study aims to develop and identify inhibitor substitutes from a library of kidney stone prescriptions in traditional Chinese medicines to prevent pathological kidney stone formation. Materials and methodsAs many as twenty Chinese medicines were extracted and separated into five different polar extracts, the inhibition performance of which on CaOx crystallization was explored by recording and comparing crystallization kinetics. The potential inhibitor molecules in the inhibitory extracts were confirmed by HPLC and their retardation efficacy was evaluated by quantifying nucleation and growth kinetics using colorimetry. Then the inhibitor-COM crystal interactions and specificity were examined by morphology evolution and surface structure analysis. In vitro inhibition performance of inhibitors on crystal growth and attachment of CaOx crystals to human renal epithelial cells were further evaluated by recording the nucleation and adhesive crystal numbers. Results and conclusionWater- and n-butanol- soluble extracts from 20 kinds of herbs show almost 100% inhibition percentage, and the n-butanol extracts was found better than commercial drug citrate. Twenty-one molecule substitutes were identified from these extracts, and among them polyphenols display the best inhibition efficacy to retard CaOx crystallization. The high-throughput colorimetric assay and morphology examinations reveals thirteen out of 21 molecules show inhibition potential and disrupt growth of CaOx monohydrate crystals by interacting with exposed Ca2+ and C2O42− on the (100) and (010) surfaces. Moreover, these inhibitors also display pronounced performance in protecting renal epithelial cells by inhibiting nucleation and adhesion of CaOx crystals to cells, thus reducing stone formation. The structure-performance correlation among 19 screened molecules that inhibitors having pKa<3.5, logD (pH = 6) <0, H-number>0.1 mmol are the best in suppressing CaOx crystallization. Our findings provide a novel solution to design and manufacture inhibitor drugs from Chinese medicines for preventing pathological kidney stones formation.

A Study of Magnetic Induction Tomography (MIT) for Calcium Oxalate Renal Screening

Nephrolithiasis is a process of stone formation in the kidney by crystallization. The increasing prevalence of nephrolithiasis from time to time had sought an alternative from the conventional imaging techniques that is invasive, radiative, and non-rapid usage. This paper enclosed a design simulation study of Magnetic Induction Tomography (MIT) system using COMSOL Multiphysics for renal imaging. MIT is a soft field tomography and non-contact imaging modality which can project the passive electromagnetic properties (conductivity, permittivity and permeability) under the principle of electromagnetic induction. In this research also, 8 copper trans-receiver coils were employed in the MIT system and fixed by the insulation belt. Meanwhile, geometric set-up of renal organ was set to imitate the transverse section of human renal. In the methodology, sensor performance analyses were done using frequency ranging from 50 kHz to 2 MHz of the MIT system on radii of calcium oxalate in renal. The sensor response and pattern is discussed in this paper.

Dual modulatory effects of diosmin on calcium oxalate kidney stone formation processes: Crystallization, growth, aggregation, crystal-cell adhesion, internalization into renal tubular cells, and invasion through extracellular matrix

Diosmin is a natural flavone glycoside (bioflavonoid) found in fruits and plants with several pharmacological activities. It has been widely used as a dietary supplement or therapeutic agent in various diseases/disorders. Although recommended, evidence of its protective mechanisms against kidney stone disease (nephrolithiasis/urolithiasis), especially calcium oxalate (CaOx) monohydrate (COM) that is the most common type, remained unclear. In this study, we thus systematically evaluated the effects of diosmin (at 2.5–160 nM) on various stages of kidney stone formation processes, including COM crystallization, crystal growth, aggregation, crystal-cell adhesion, internalization into renal tubular cells and invasion through extracellular matrix (ECM). The results showed that diosmin had dose-dependent modulatory effects on all the mentioned COM kidney stone processes. Diosmin significantly increased COM crystal number and mass during crystallization, but reduced crystal size and growth. While diosmin promoted crystal aggregation, it inhibited crystal-cell adhesion and internalization into renal tubular cells. Finally, diosmin promoted crystal invasion through the ECM. Our data provide evidence demonstrating both inhibiting and promoting effects of diosmin on COM kidney stone formation processes. Based on these dual modulatory activities of diosmin, its anti-urolithiasis role is doubtful and cautions should be made for its use in kidney stone disease.