Role of bacteria in the development of kidney stones

Metabolic Evaluation and Recurrence Prevention for Urinary Stone Patients: An EAU Guidelines Update

BACKGROUND AND OBJECTIVE

The aim of this review was to define patients who are at high risk of recurrence of urolithiasis, to delineate diagnostic and therapeutic algorithms for each type of stone, and to clarify general guidelines and recommendations for prevention of recurrence.

METHODS

A professional research librarian carried out literature searches for all sections of the urolithiasis guidelines, covering the timeframe between 1976 and June 2023.

KEY FINDINGS AND LIMITATIONS

For every patient with urolithiasis, an attempt should be made to analyse the stone. Patients should be given general instructions on how to prevent recurrence, including adequate fluid and calcium intake, and low consumption of sodium and protein. Identifying and correcting the causative factors is a cornerstone in preventing the recurrence of urolithiasis. Diagnostic and therapeutic algorithms by stone composition are available. Every patient should undergo baseline metabolic screening, while patients with calcium stones, who are at high risk of relapse and complications, should undergo extensive metabolic screening with two 24-h urine collections and should receive targeted therapy. Patients with uric acid, infection, or cystine stones are at high risk of relapse. All patients at high risk of recurrence should be closely monitored, especially those not complying with therapy in the long term.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Metabolic stone evaluation and patient follow-up are highly recommended to prevent urolithiasis recurrence.

PATIENT SUMMARY

We reviewed the evidence for proper evaluation of patients with urinary and stones and the treatment options for preventing stone recurrence. It is essential to determine the type of stone and to carry out specific blood and urine tests for planning the best treatment course for each patient.

Thymoquinone: An Effective Natural Compound for Kidney Protection

Kidney disease is a common health problem worldwide. Acute or chronic injuries may interfere with kidney functions, eventually resulting in irreversible kidney damage. A number of recent studies have shown that the plant-derived natural products have an extensive potential for renal protection. Thymoquinone (TQ) is an essential compound derived from Nigella Sativa (NS), which is widely applied in the Middle East as a folk medicine. Previous experiments have demonstrated that TQ has a variety of potential pharmacological effects, including anti-oxidant, antibacterial, antitumor, immunomodulatory, and neuroprotective activities. In particular, the prominent renal protective efficacy of TQ has been demonstrated in both in vivo and in vitro experiments. TQ can prevent acute kidney injuries from various xenobiotics through anti-oxidation, anti-inflammatory, and anti-apoptosis effects. In addition, TQ exhibited significant pharmacological effects on renal cell carcinoma, renal fibrosis, and urinary calculi. The essential mechanisms involve scavenging ROS and increasing anti-oxidant activity, decreasing inflammatory mediators, inducing apoptosis, and inhibiting migration and invasion. The purpose of this review is to conclude the pharmacological effects and the potential mechanisms of TQ in renal protection, shedding new light on the exploration of medicinal phyto-protective agents targeting kidneys.

Urological Guidelines for Kidney Stones: Overview and Comprehensive Update

BACKGROUND

Evidence-based guidelines are published by urological organisations for various conditions, including urolithiasis. In this paper, we provide guidance on the management of kidney stone disease (KSD) and compare the American Urological Association (AUA) and European Association of Urologists (EAU) guidelines.

METHODS

We evaluate and appraise the evidence and grade of recommendation provided by the AUA and EAU guidelines on urolithiasis (both surgical and medical management).

RESULTS

Both the AUA and EAU guidelines provide guidance on the type of imaging, treatment options, and medical therapies and advice on specific patient groups, such as in paediatrics and pregnancy. While the guidelines are generally aligned and based on evidence, some subtle differences exist in the recommendations, but both are generally unanimous for the majority of the principles of management.

CONCLUSIONS

We recommend that the guidelines should undergo regular updates based on recently published material, and while these guidelines provide a framework, treatment plans should still be personalised, respecting patient preferences, surgical expertise, and various other individual factors, to offer the best outcome for kidney stone patients.

Antibacterial properties and urease suppression ability of Lactobacillus inhibit the development of infectious urinary stones caused by Proteus mirabilis

Infectious urolithiasis is a type of urolithiasis, that is caused by infections of the urinary tract by bacteria producing urease such as Proteus mirabilis. Lactobacillus spp. have an antagonistic effect against many pathogens by secreting molecules, including organic acids. The aim of the study was to determine the impact of Lactobacillus strains isolated from human urine on crystallization of urine components caused by P. mirabilis by measuring bacterial viability (CFU/mL), pH, ammonia release, concentration of crystallized salts and by observing crystals by phase contrast microscopy. Moreover, the effect of lactic acid on the activity of urease was examined by the kinetic method and in silico study. In the presence of selected Lactobacillus strains, the crystallization process was inhibited. The results indicate that one of the mechanisms of this action was the antibacterial effect of Lactobacillus, especially in the presence of L. gasseri, where ten times less P. mirabilis bacteria was observed, compared to the control. It was also demonstrated that lactic acid inhibited urease activity by a competitive mechanism and had a higher binding affinity to the enzyme than urea. These results demonstrate that Lactobacillus and lactic acid have a great impact on the urinary stones development, which in the future may help to support the treatment of this health problem.

The Saudi urological association guidelines on urolithiasis

Aims

The Saudi Urolithiasis Guidelines are a set of recommendations for diagnosing, evaluating, and treating urolithiasis in the Saudi population. These guidelines are based on the latest evidence and expert consensus to improve patient outcomes and optimize care delivery. They cover the various aspects of urolithiasis, including risk factors, diagnosis, medical and surgical treatments, and prevention strategies. By following these guidelines, health-care professionals can improve care quality for individuals with urolithiasis in Saudi Arabia.

Panel

The Saudi Urolithiasis Guidelines Panel consists of urologists specialized in endourology with expertise in urolithiasis and consultation with a guideline methodologist. All panelists involved in this document have submitted statements disclosing any potential conflicts of interest.

Methods

The Saudi Guidelines on Urolithiasis were developed by relying primarily on established international guidelines to adopt or adapt the most appropriate guidance for the Saudi context. When necessary, the panel modified the phrasing of recommendations from different sources to ensure consistency within the document. To address areas less well covered in existing guidelines, the panel conducted a directed literature search for high quality evidence published in English, including meta analyses, randomized controlled trials, and prospective nonrandomized comparative studies. The panel also searched for locally relevant studies containing information unique to the Saudi Arabian population. The recommendations are formulated with a direction and strength of recommendation based on GRADE terminology and interpretation while relying on existing summaries of evidence from the existing guidelines.

Substances Secreted by Lactobacillus spp. from the Urinary Tract Microbiota Play a Protective Role against Proteus mirabilis Infections and Their Complications

Proteus mirabilis urinary tract infections can lead to serious complications such as development of urinary stones. Lactobacillus spp., belonging to the natural microbiota of the urinary tract, exhibit a number of antagonistic mechanisms against uropathogens, including the secretion of organic acids. In this study, we determined the anti-adhesion, anti-cytotoxicity and anti-crystallization properties of the substances secreted by Lactobacillus. For this purpose, membrane inserts with a pore diameter 0.4 μm were used, which prevent mixing of cultured cells, simultaneously enabling the diffusion of metabolic products. The intensity of crystallization was assessed by measuring the levels of Ca2+, Mg2+ and NH3 and by observing crystals using microscopic methods. The cytotoxicity of the HCV-29 cell line was determined using the LDH and MTT assays, and the impact of lactobacilli on P. mirabilis adhesion to the bladder epithelium was assessed by establishing CFU/mL after cell lysis. It was shown that in the presence of L. gasseri the adhesion of P. mirabilis and the cytotoxicity of the cells decreased. The degree of crystallization was also inhibited in all experimental models. Moreover, it was demonstrated that L. gasseri is characterized by the secretion of a high concentration of L-lactic acid. These results indicate that L-lactic acid secreted by L. gasseri has a significant impact on the crystallization process and pathogenicity of P. mirabilis.

Pyelo-hepatic abscess caused by staghorn stone infection: a case report

BACKGROUND

The most common source of pyogenic liver abscess is biliary tract infection. Other less common routes include the spread of bacteria from distant foci. However, direct extension of a perinephric infection focus to the liver is extremely rare.

CASE REPORT

The patient was a non-diabetic, immunocompetent, 29-year-old woman of mixed race ancestry with a history of recurrent urinary tract infections who was referred to our hospital because of an ultrasound-detected liver abscess. She was initially treated with metronidazole for 20 days at the referring institution for suspected amebic abscess without improvement. On admission to our center, she was febrile and complained of a dull right upper quadrant pain. A POCUS ultrasound suggested a pyogenic abscess, probably from a staghorn calculus infection. She received meroperem and amikacin for 22 and 10 days, respectively. Repeat hemocultures showed no growth, but urine cultures were positive for Proteus sp. Complete remission of clinical and imaging findings was observed under antibiotics. The patient was referred to the urology outpatient clinic to discuss the option of radical nephrectomy. CONCLUSION : This case underlines the high morbidity of staghorn calculi.

Mineralogy, geochemistry, and micromorphology of human kidney stones (urolithiasis) from Mersin, the southern Turkey

This study describes the primary characteristics of the selected kidney stones surgically removed from the patients at the Mersin University Hospital in the southern Turkey and interprets their formation via petrographic, geochemical, XRD, SEM-EDX, and ICP-MS/OES analyses. The analytical results revealed that the kidney stones are composed of the minerals whewellite, struvite, hydroxyapatite, and uric acid alone or in different combinations. The samples occur in staghorn, bean-shaped composite, and individual rounded particle shapes, which are controlled by the shape of the nucleus and the site of stone formation. The cross-section of the samples shows concentric growth layers due to variations in saturation, characterizing the metastable phase. Kidney stone formation includes two main stages: (i) nucleation and (ii) aggregation and/or growth. Nucleation was either Randall plaque of hydroxyapatite in tissue on the surface of the papilla or a coating of whewellite on the plaque, or crystallization as free particles in the urine. Subsequently, aggregation or growth occurs by precipitation of stone-forming materials around the plaque or coating carried into the urine, or around the nucleus formed in situ in the urine. Urinary supersaturation is the main driving force of crystallization processes; and is controlled by many factors including bacterially induced supersaturation.

Surgery for Xanthogranulomatous Pyelonephritis: A Comparison of Midline Transperitoneal and Flank Retroperitoneal Laparotomy Approaches to Nephrectomy

Xanthogranulomatous pyelonephritis (XGP) is a rare inflammatory disease often associated with high morbidity and mortality. Whether the midline transperitoneal or the flank retroperitoneal approach is superior remains unknown. We searched through pathology databases and reviewed 86 patients with an XGP diagnosis from 2000 to 2021 at our institution. After the patients who did not meet the inclusion criteria were excluded, 35 patients who had undergone nephrectomy through the midline transperitoneal or the flank retroperitoneal laparotomy approach were recruited. Nine (25.71%) of the thirty-five patients underwent nephrectomy through a midline approach, whereas twenty-six (74.29%) received a flank approach. Patients in the midline approach group had a longer surgical time (p = 0.03) than those in the flank approach group. In addition, patients in the flank approach group took less time after surgery to resume oral intake than those in the midline approach group (p = 0.01). No significant differences in the rates of intraoperative and postoperative complications such as peritonitis or intraabdominal infection were observed between the groups. For the patients with XGP who are good candidates for surgery, nephrectomy is a relatively safe surgical treatment method. Both surgical methods produced favorable surgical outcomes, and the patients who received these methods had similar complication rates.

Large database study of urinary stone composition in South Korea: Korean Society of Endourology and Robotics (KSER) research series

Purpose

To evaluate the characteristics of urinary stone composition in a Korean population using a large database of stone composition.

Materials and Methods

From January 1, 2014, to June 30, 2019, a total of 33,078 urinary stone composition data were analyzed. Stone composition was classified into four main groups: calcium oxalate (CaOx), struvite, uric acid (UA), and calcium phosphate (CaP). We examined the relationship between stone composition and sex, age, geographic region, calendar month, and season.

Results

The CaOx group (46.41%) was the largest, followed by the struvite group (29.66%), UA group (19.61%), and CaP group (4.32%). The CaOx group tended to decrease with age, but the UA group increased with age. Also, the CaOx group had the highest percentage in summer and the lowest in spring (p<0.001). The struvite and CaP groups had higher percentages of females than males (struvite: 36.6% vs. 25.7%, p<0.001; CaP: 6.2% vs. 3.3%, p<0.001). Conversely, the UA stones were more common in males than in females (24.5% vs. 11.0%, p<0.001). The UA group had the lowest percentage in the capital region (p<0.001). The total male-to-female ratio decreased over time from 1.95:1 in 2014 to 1.67:1 in 2018 (p<0.001).

Conclusions

There were differences for each stone composition in the percentages according to sex, age, geographic region, month, and season. Identifying these differences based on the stone composition is vital for the treatment and prevention of urinary stones.

Aggregation of poorly crystalline and amorphous components of infectious urinary stones is mediated by bacterial lipopolysaccharide

Poorly crystalline and amorphous precipitate (PCaAP) is one of the components of the so-called infectious urinary stones, which are the result of the activity of urease-producing microorganisms, mainly from the Proteus species, in particular Proteus mirabilis. The main component of this kind of stones is crystalline struvite (MgNH4PO4∙6H2O). Bacteria can build into the structure of the urinary stone and, in this way, they are one of the components of the urinary stone. From these three components - PCaAP, struvite and Proteus mirabilis - PCaAP exhibits the greatest ability to aggregate. The present study focuses on the aggregation of PCaAP. In particular, an influence of lipopolysaccharide (LPS) isolated from Proteus mirabilis on aggregation of PCaAP is presented. An aggregation of PCaAP is characterized by cross-sectional area of aggregates and zeta potential. The results demonstrate that, in artificial urine, the influence of freely suspended LPS on aggregation of PCaAP depends on the concentrations of LPS. Small concentrations of freely suspended LPS enhance the aggregation of PCaAP compared to the control test. For high concentrations of freely suspended LPS the formation of aggregates of PCaAP is inhibited. LPS, which is not freely suspended, but covers polystyrene latex beads, has no such properties. The investigations provide evidence for the importance of biological regulation in the PCaAP aggregation process.

Trace elements in struvite equine enteroliths: Concentration, speciation and influence of diet

Equine enteroliths ∼1.5cm in diameter were collected from an Arabian horse in Louisville, Kentucky, United States. Scanning electron microscopy (SEM) and light microscope imaging of a sectioned enterolith showed two distinct regions of concentric growth outward from the central nidus, a small pebble. After initial growth, acidic colonic fluids permeated the stone inducing recrystallization and alteration of crystals closest to the nidus. A second growth event, when mineral crystallization was again favorable, produced an outer region of unaltered crystals at the rim. The mineral was identified as struvite (MgNH₄PO₄∙6H₂O) by powder X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Elemental analysis confirmed concentrations of P, Mg and N consistent with the struvite composition, and detected trace elements Fe (1050-1860mgkg^-1), Mn (262-280mgkg^-1) and Zn (197-238mgkg^-1). All elements were traced to dietary sources, with the Fe:Mn:Zn ratio of the enterolith consistent with that of the horse feed. X-ray absorption fine structure (XAFS) spectroscopy at the Zn K-edge revealed distorted ZnO₄ tetrahedra located between crystallographic planes in the struvite structure forming bidentate linkages to struvite phosphate groups. Emplacement of Zn in structural cavities likely occurs during struvite crystallization. Trace elements and organic impurities increase susceptibility of the enterolith to heat-induced decomposition relative to pure struvite, which could be a consideration for treatment. Results reveal enterolith growth processes, composition and mechanisms of trace metal accumulation that can inform management and prevention of equine enteroliths.

No stone unturned: The presence of kidney stones in a skeleton from 19th century Peoria, Illinois

During the excavation of the 19th century Peoria City Cemetery (Peoria, Illinois), a skeleton of a female, aged 20-30 years old, was found with large, bilateral calcified masses in the abdominal region. The masses were analyzed by Fourier transform infrared (FTIR) spectroscopy, and the results compared to published clinical data in an effort to determine the etiology of the stones. The calcified masses were determined to be staghorn struvite uroliths, which commonly result from chronic urinary tract infection and likely impacted the overall health of this individual.

Role of calcium-depositing bacteria Agrobacterium tumefaciens and its influence on corrosion of different engineering metals used in cooling water system

The present investigation deals with the role of calcium-depositing bacterial community on corrosion of various engineering metals, namely, brass alloy (BS), copper (Cu), stainless steel (SS) and mild steel (MS). Based on the corrosion behavior, Agrobacterium tumefaciens EN13, an aerobic bacterium is identified as calcium-depositing bacteria on engineering metals. The results of the study are supported with biochemical characterization, 16S rRNA gene sequencing, calcium quantification, weight loss, electrochemical (impedance and polarization) and surface analysis (XRD and FTIR) studies. The calcium quantification study showed carbonate precipitation in abiotic system/biotic system as 50 and 700 ppm, respectively. FTIR results too confirmed the accumulation of calcium deposits from the environment on the metal surface by EN13. Electrochemical studies too supported the corrosion mechanism by showing a significant increase in the charge transfer resistance (R_ct) of abiotic system (44, 33.6, 45, 29.6 Ω cm²) than compared to biotic system (41, 10.1 29 and 25 Ω cm²). Hence, the outcome of the present study confirmed the enhanced bioaccumulation behavior of calcium by the strain, EN13.

Stones in special situations

There are several special situations in which urinary lithiasis presents management challenges to the urologist. An in-depth knowledge of the pathophysiology, unique anatomy, and treatment options is crucial in order to maintain good health in these patients. In this review, we summarize the current literature on the management of the following scenarios: bladder stones, stones in bowel disease, during pregnancy, in association with renal anomalies, with skeletal deformities, in urinary diversions, and in children.

Necrotizing suppurative nephritis in a Japanese black feedlot steer due to Proteus mirabilis infection

A Japanese black feedlot steer suddenly died after exhibiting astasia and cramping of the extremities. Necropsy of the animal revealed that the right kidney was enlarged and pale with severe nephrolithiasis. The urinary bladder displayed mucosal hemorrhage. Upon bacteriological investigation, Proteus mirabilis was isolated from the liver, spleen, right kidney, lungs and urine. Histopathological examination revealed necrotizing suppurative nephritis with the presence of numerous gram-negative bacilli and fibrinous suppurative cystitis with no bacilli. Immunohistochemical analysis revealed that the bacteria and cytoplasm of the macrophages stained positively with P. mirabilis antiserum. Electron microscopy revealed the presence of numerous bacteria in the renal tubules. To our knowledge, this is the first report describing the histopathological aspects of nephritis caused by P. mirabilis in cattle.

Ureolytic Biomineralization Reduces Proteus mirabilis Biofilm Susceptibility to Ciprofloxacin

Ureolytic biomineralization induced by urease-producing bacteria, particularly Proteus mirabilis, is responsible for the formation of urinary tract calculi and the encrustation of indwelling urinary catheters. Such microbial biofilms are challenging to eradicate and contribute to the persistence of catheter-associated urinary tract infections, but the mechanisms responsible for this recalcitrance remain obscure. In this study, we characterized the susceptibility of wild-type (ure+) and urease-negative (ure-) P. mirabilis biofilms to killing by ciprofloxacin. Ure+ biofilms produced fine biomineral precipitates that were homogeneously distributed within the biofilm biomass in artificial urine, while ure- biofilms did not produce biomineral deposits under identical growth conditions. Following exposure to ciprofloxacin, ure+ biofilms showed greater survival (less killing) than ure- biofilms, indicating that biomineralization protected biofilm-resident cells against the antimicrobial. To evaluate the mechanism responsible for this recalcitrance, we observed and quantified the transport of Cy5-conjugated ciprofloxacin into the biofilm by video confocal microscopy. These observations revealed that the reduced susceptibility of ure+ biofilms resulted from hindered delivery of ciprofloxacin into biomineralized regions of the biofilm. Further, biomineralization enhanced retention of viable cells on the surface following antimicrobial exposure. These findings together show that ureolytic biomineralization induced by P. mirabilis metabolism strongly regulates antimicrobial susceptibility by reducing internal solute transport and increasing biofilm stability.

Biochemical and Pathological Study of Hydroalcoholic Extract of Achillea millefolium L. on Ethylene Glycol-Induced Nephrolithiasis in Laboratory Rats

BACKGROUND

Nephrolithiasis is of the most prevalent urinary tract disease. It seems worthwhile to replace the conventional treatments with more beneficial and safer agents, particularly herbal medicines which are receiving an increasing interest nowadays.

AIMS

In this study, we investigated the protective and curative effects of Achillea millefolium L. on ethylene glycol (EG)-induced nephrolithiasis in rats.

MATERIALS AND METHODS

The extract of A. millefolium was prepared by soxhlet method. Forty male Wistar rats were randomly divided into five groups (N = 8) as follows. The negative control (group A) received tap drinking water. Rats in sham (positive control group B), curative (group C and D), and preventive (group E) groups all received 1% EG in drinking water according to the experimental protocol for 30 days. In the curative groups, dosages of 200 and 400 mg/kg body weight (BW) of A. millefolium extract were administered orally from day 15 to the end of the experiment, group C and D, respectively. Group E received 200 mg/kg A. millefolium extract from the 1(st) day throughout the experiment. Urinary oxalate and citrate concentrations were measured by spectrophotometer on the first and 30(th) days. On day 31, the kidneys were removed and examined histopathologically for counting the calcium oxalate (CaOx) deposits in 50 microscopic fields.

RESULTS

In the curative and preventive groups, administration of A. millefolium extract showed significant reduction in urinary oxalate concentration (P < 0.05). Also, urinary citrate concentration was significantly increased in group C, D, and E. The CaOx deposits significantly decreased in group C to E compared with the group B.

CONCLUSIONS

According to our results, A. millefolium extract had preventive and curative effects on EG-induced renal calculi.

Secondarily infected nonstruvite urolithiasis: a prospective evaluation

OBJECTIVE

To characterize patients who form nonstruvite stones associated with infection (secondarily infected calculi), and to define the bacteria associated with these.

MATERIALS AND METHODS

Patients undergoing percutaneous nephrolithotomy were prospectively recruited. Medical records were reviewed, and stones were analyzed using micro computed tomography and infrared spectroscopy. A fragment of each stone was sent for bacterial culture. Patients were categorized by stone culture results (SC ±) and the presence of struvite (ST ±). The Fisher exact test was used for comparison of proportion. Sterility of intraoperative SC was established with independently collected controls.

RESULTS

In total, 125 patients were enrolled: 24 SC+/ST-, 19 SC+/ST+, and 82 SC-/ST-. Proportions of patients with prior urologic surgery, diabetes, and immunodeficiency were similar between groups. Patients with neurogenic bladder were more likely to have SC+/ST+ stones or SC+/ST- stones than SC-/ST- stones (26% vs 8% vs 0%, respectively; P <.01). Among patients with metabolic evaluations, hypocitraturia was found in 31.6% (6 of 19) SC+/ST- patients, 46.7% (7 of 15) SC+/ST+ patients, and 26.0% (19 of 73) of SC-/ST- patients (P = .28). Approximately 40% of cultured organisms in the secondarily infected calculi possessed urease and another 40% citrate lyase activities.

CONCLUSION

Secondarily infected stones were detected in approximately 20% of this surgical cohort and may be more common than previously appreciated. Neurogenic bladder appeared to predispose patients to either struvite or secondarily infected stones. The role of bacterial infection in stone formation is unclear but may include alteration of urinary components, acting as a nidus for crystallization, or inducing inflammation.

The inhibitory effect of an ethanol extract of the spores of Lygodium japonicum on ethylene glycol-induced kidney calculi in rats

We investigated the effect of an ethanol extract of Lygodii spora (LS) as a preventive and therapeutic agent for experimentally induced calcium oxalate nephrolithiasis with ethylene glycol (EG) in rats. Male Wistar rats were randomly divided into preventive (n = 18, for 28 days) and therapeutic (n = 24, for 42 days) groups. The preventive group was further subdivided into three groups of six rats each: preventive control, preventive lithiatic control (EG) and preventive lithiatic LS (EG + 400 mg/kg LS). Similarly, the therapeutic group was subdivided into four groups of six rats each: therapeutic control, therapeutic lithiatic control, therapeutic lithiatic untreated, and therapeutic lithiatic LS. Lithiasis was induced by adding 0.75% EG to the drinking water of all groups except the preventive and therapeutic control groups. Preventive and therapeutic subjects also received the LS ethanol extract in drinking water at a dose of 400 mg/kg, since day 0 or day 28, respectively. At the end of the each experimental period, various biochemical parameters were measured in urine and kidney homogenates. The kidneys were subjected to histopathological analysis. The results revealed that treatment with the LS preventive protocol significantly decreased the levels of urinary calcium, oxalate and uric acid, and increased the levels of urinary citrate as compared to those in the EG control. No significant changes in the urinary parameters except oxalate and citrate levels were observed in the rats in the therapeutic protocol. In both preventive and therapeutic protocols, the extract significantly decreased kidney peroxides, renal calcium, oxalate content, and the number of kidney oxalate deposits as compared to those in the EG group. We conclude that LS is useful as a preventive and therapeutic agent against the formation of oxalate kidney stones.

Cystoman® and calculi: a good alternative to standard therapies in preventing stone recurrence

To assess the efficacy and tolerability of D-mannose-containing product (Cystoman(®)) in preventing recurrence in patients who underwent surgical treatment for infection related urinary stones. From January 2011 to February 2013 we have enrolled all consecutive patients affected by staghorn calculi and recurrent urinary tract infections (UTIs). All patients recommended for surgery were scheduled for percutaneous nephrolithotomy. The study agent was administered daily for 5 months after surgical procedure. At baseline and 5-month follow-up all patients underwent abdominal Computed Tomography (CT) scan and they also completed Medical Outcomes Study short-form, 36-item questionnaire (SF-36). They performed urine and urine culture monthly. The primary endpoints were the assessment of the efficacy with regard to infection-related urinary stone recurrence and the tolerability of Cystoman(®). The secondary endpoint was the evaluation of quality-of-life symptoms. During the study period, a total of 27 patients were included in the study. The data from 25 patients were analyzable. Seventeen patients (68%) did not report UTIs during follow-up. Eight patients (32%) remained infected and the average number of UTIs was 2.6 ± 1.6 in 5 months. At 5-month follow-up 17 (68%) patients were free from stones recurrence; in 8 (32%) cases CT scan revealed stone recurrence with an average stone diameter of 1.1 ± 0.4 cm. In nonrecurring patients, 2 (11.7%) reported an average of 1.5 ± 0.7 UTIs episodes; in recurring patients, 6 (75%) showed 3 ± 1.67 of UTIs episodes. Statistically significant differences were seen in the occurrence of UTIs episodes were detected between nonrecurring stone patients and recurring patients (p < 0.05). Moreover, statistically significant changes were detected in SF-36 scores from baseline to month 5 in the categories of physical functioning and energy/fatigue (p < 0.05). Cystoman(®) is effective in preventing infection-related urinary stones.

Alcea rosea root extract as a preventive and curative agent in ethylene glycol-induced urolithiasis in rats

Introduction:

Alcea rosea L. is used in Asian folk medicine as a remedy for a wide range of ailments. The aim of the present study was to investigate the effect of hydroalcoholic extract of Alcea rosea roots on ethylene glycol-induced kidney calculi in rats.

Materials and Methods:

Male Wistar rats were randomly divided into control, ethylene glycol (EG), curative and preventive groups. Control group received tap drinking water for 28 days. Ethylene glycol (EG), curative and preventive groups received 1% ethylene glycol for induction of calcium oxalate (CaOx) calculus formation; preventive and curative subjects also received the hydroalcoholic extract of Alcea rosea roots in drinking water at dose of 170 mg/kg, since day 0 or day 14, respectively. Urinary oxalate concentration was measured by spectrophotometer on days 0, 14 and 28. On day 28, the kidneys were removed and examined histopathologically under light microscopy for counting the calcium oxalate deposits in 50 microscopic fields.

Results:

In both preventive and curative protocols, treatment of rats with hydroalcoholic extract of Alcea rosea roots significantly reduced the number of kidney calcium oxalate deposits compared to ethylene glycol group. Administration of Alcea rosea extract also reduced the elevated urinary oxalate due to ethylene glycol.

Conclusion:

Alcea rosea showed a beneficial effect in preventing and eliminating calcium oxalate deposition in the rat kidney. This effect is possibly due to diuretic and anti-inflammatory effects or presence of mucilaginous polysaccharides in the plant. It may also be related to lowering of urinary concentration of stone-forming constituents.

Acidic environments induce differentiation of Proteus mirabilis into swarmer morphotypes

Although swarmer morphotypes of Proteus mirabilis have long been considered to result from surfaced-induced differentiation, the present findings show that, in broth medium containing urea, acidic conditions transform some swimmer cells into elongated swarmer cells. This study has also demonstrates that P. mirabilis cells grown in acidic broth medium containing urea enhance virulence factors such as flagella production and cytotoxicity to human bladder carcinoma cell line T24, though no significant difference in urease activity under different pH conditions was found. Since there is little published data on the behavior of P. mirabilis at various hydrogen-ion concentrations, the present study may clarify aspects of cellular differentiation of P. mirabilis in patients at risk of struvite formation due to infection with urease-producing bacteria, as well as in some animals with acidic or alkaline urine.

Effect of Curcumin Against Proteus mirabilis During Crystallization of Struvite from Artificial Urine

We investigated the activity of curcumin against Proteus mirabilis and the struvite crystallization in relation to urinary stones formation. In order to evaluate an activity of curcumin we performed an in vitro experiment of struvite growth from artificial urine. The crystallization process was induced by Proteus mirabilis to mimic the real urinary tract infection, which usually leads to urinary stone formation. The results demonstrate that curcumin exhibits the effect against Proteus mirabilis inhibiting the activity of urease—an enzyme produced by these microorganisms. Addition of curcumin increases the induction time and decreases the efficiency of growth of struvite compared with the absence of curcumin. Interestingly, the addition of curcumin does not affect the crystal morphology and habit. In conclusion, curcumin has demonstrated its significant potential to be further investigated for its use in the case of struvite crystallization induced for the growth by Proteus mirabilis in relation to urinary stone formation.

Magnesium-sputtered titanium for the formation of bioactive coatings

Osteoconductive coatings may improve the clinical performance of implanted metallic biomaterials. Several low-temperature coating methods have been reported where a supersaturated solution is used to deposit typically apatitic materials. However, due to the very low solubility of apatite, the concentration of calcium and phosphate ions attainable in a supersaturated solution is relatively low ( approximately 1-2mM), thus coating formation is slow, with several solution changes required to form a uniform and clinically relevant coating. In order to avoid this problem, we present a novel method where substrates were initially sputter coated with pure magnesium metal and then immersed in differing phosphate solutions. In this method, upon immersion the implant itself becomes the source of cations and only the anions to be incorporated into the coating are present in solution. These ions react rapidly, forming a continuous coating and avoiding problems of premature non-localized precipitation. The different coatings resulting from varying the phosphate solutions were then characterized in terms of morphology and composition by microscopy and chemical analyses. Upon immersion of the sputter-coated metals into ammonium phosphate solution, it was found that a uniform struvite (MgNH(4)PO(4).6H(2)O) coating was formed. Upon subsequent immersion into a calcium phosphate solution, stable coatings were formed. The coated surfaces also enhanced both osteoblastic cellular adhesion and cell viability compared to bare titanium. The concept of sputter-coating a reactive metal to form an adherent inorganic metal coating appears promising in the field of developing rapid-forming low-temperature bioceramic coatings.

Interaction of intracorporeal lithotripters with Proteus mirabilis inoculated inside artificial calcium and struvite stones

BACKGROUND AND PURPOSE

Renal calculi may contain bacteria that can remain active inside the stone and produce bacteremia and/or endotoxemia after lithotripsy. Urinary tract infection associated with urinary stones represents high morbidity. The purpose of this research was to use novel artificial struvite stones inoculated with living bacteria and to study the effect of four different intracorporeal lithotripters on bacterial inactivation after in vitro lithotripsy.

MATERIALS AND METHODS

Two types of artificial kidney stone models (calcium sulphate and mixed struvite-calcium sulphate) were manufactured and infected with Proteus mirabilis. Stones were fractured using either electrohydraulic, laser, ultrasonic, or pneumatic lithotripters. Bacterial viability was determined before and after the lithotripsy.

RESULTS

Bacterial inactivation was not affected by the stone matrix; ie, calcium or struvite. The four tested lithotripters were almost equally efficient at reducing the viability of P mirabilis in both the low and the high energy setting.

CONCLUSIONS

We were able to obtain novel artificial struvite stones infected with bacteria. Intracorporeal lithotripters are efficient at reducing the viability of P mirabilis in vitro. Tested stone materials play a minor role regarding inactivation. Whether the bactericidal effect reported is desirable or not is still to be answered, because the presence of endotoxin from cell lysis may increase the risk of urosepsis.

Pathogenesis of renal calculi

Recent reports suggest that kidney stone disease prevalence is increasing. Despite significant treatment advances, the inciting factor and sequence of events leading to kidney stone formation remain elusive; however, recent efforts to understand the pathogenesis of nephrolithiasis have led to a delineation of the human surgical anatomy, histopathology, and metabolic factors in a variety of kidney stone formers. This article reviews the fundamental concepts of calculus formation, and the leading theories of stone pathogenesis, focusing on recent data from human papillary and renal cortical biopsies in stone formers that provide evidence for the role of Randall's plaque in kidney stone disease pathogenesis. These data suggest there are individual stone-forming phenotypes with unique surgical anatomy, histology, and metabolic profiles.

N/A

N/A

Influence of cranberry juice on the urinary risk factors for calcium oxalate kidney stone formation

OBJECTIVE

To investigate the potential influence of cranberry juice on urinary biochemical and physicochemical risk factors associated with the formation of calcium oxalate kidney stones, as this product might affect the chemical composition of urine.

SUBJECTS AND METHODS

Urinary variables were assessed in a randomized cross-over trial in 20 South African men (students) with no previous history of kidney stones. The first group of 10 subjects drank 500 mL of cranberry juice diluted with 1500 mL tap water for 2 weeks, while the second group drank 2000 mL of tap water for the same period. This was followed by a 2-week 'washout' period before the two groups crossed over. During the experimental phase subjects kept a 3-day food diary to assess their dietary and fluid intakes; 24-h urine samples were collected at baseline and on day 14 of the trial periods, and analysed using modern laboratory techniques. Urine analysis data were used to calculate the relative urinary supersaturations of calcium oxalate, uric acid and calcium phosphate. Data were assessed statistically by analysis of variance.

RESULTS

The ingestion of cranberry juice significantly and uniquely altered three key urinary risk factors. Oxalate and phosphate excretion decreased while citrate excretion increased. In addition, there was a decrease in the relative supersaturation of calcium oxalate, which tended to be significantly lower than that induced by water alone.

CONCLUSION

Cranberry juice has antilithogenic properties and, as such, deserves consideration as a conservative therapeutic protocol in managing calcium oxalate urolithiasis.

Crystallization of urine mineral components may depend on the chemical nature of Proteus endotoxin polysaccharides

Formation of infectious urinary calculi is the most common complication accompanying urinary tract infections by members of the genus Proteus. The major factor involved in stone formation is the urease produced by these bacteria, which causes local supersaturation and crystallization of magnesium and calcium phosphates as carbonate apatite [Ca(10)(PO(4))(6).CO(3)] and struvite (MgNH(4)PO(4).6H(2)O), respectively. This effect may also be enhanced by bacterial polysaccharides. Macromolecules of such kind contain negatively charged residues that are able to bind Ca(2+) and Mg(2+), leading to the accumulation of these ions around bacterial cells and acceleration of the crystallization process. The levels of Ca(2+) and Mg(2+) ions bound by whole Proteus cells were measured, as well as the chemical nature of isolated LPS polysaccharides, and the intensity of the in vitro crystallization process was compared in a synthetic urine. The results suggest that the sugar composition of Proteus LPS may either enhance or inhibit the crystallization of struvite and apatite, depending on its chemical structure and ability to bind cations. This points to the increased importance of endotoxin in urinary tract infections.

Urinary analysis of nephrolithiasis markers

Renal stone disease is an ancient and common affliction, common in industrialised nations. The causes and incidence of nephrolithiasis are presented. Afterwards, the promoters and inhibitors of renal stone formation analysis in urine are described including enzymatic methods, chromatography, capillary electrophoresis and other techniques. Aspects such as sample collection and storage are also included. The review article includes referenced tables that provide summaries of methodology for the analysis of nephrolithiasis related compounds.