Composition of urinary calculi: Lessons from a French epidemiologic retrospective study

Discovery of 2,8-dihydroxyadenine in HUA patients with uroliths and biomarkers for its associated nephropathy

Currently, it is acknowledged that gout is caused by uric acid (UA). However, some studies have revealed no correlation between gout and UA levels, and growing evidence suggests that 2,8-dihydroxyadenine (2,8-DHA), whose structural formula is similar to UA but is less soluble, may induce gout. Hence, we hypothesized that uroliths from hyperuricemia (HUA) patients, which is closely associated with gout, may contain 2,8-DHA. In this study, 2,8-DHA in uroliths and serum of HUA patients were determined using HPLC. Moreover, bioinformatics was used to investigate the pathogenic mechanisms of 2,8-DHA nephropathy. Subsequently, a mouse model of 2,8-DHA nephropathy established by the gavage administration of adenine, as well as a model of injured HK-2 cells induced by 2,8-DHA were used to explore the pathogenesis of 2,8-DHA nephropathy. Interestingly, 2,8-DHA could readily deposit in the cortex of the renal tubules, and was found in the majority of these HUA patients. Additionally, the differentially expressed genes between 2,8-DHA nephropathy mice and control mice were found to be involved in inflammatory reactions. Importantly, CCL2 and IL-1β genes had the maximum degree, closeness, and betweenness centrality scores. The expressions of CCL2 and IL-1β genes were significantly increased in the serum of 24 HUA patients with uroliths, indicating that they may be significant factors for 2,8-DHA nephropathy. Further analysis illustrated that oxidative damage and inflammation were the crucial processes of 2,8-DHA renal injury, and CCL2 and IL-1β genes were verified to be essential biomarkers for 2,8-DHA nephropathy. These findings revealed further insights into 2,8-DHA nephropathy, and provided new ideas for its diagnosis and treatment.

Ablation rates with Holmium:YAG and Thulium Fiber Laser: Influence of the stone phantom homogeneity. An in vitro study

OBJECTIVES

The lithotripsy efficiency (LE) in vitro study requires artificial or human stone samples (AS, HS). With the development of dusting lithotripsy, less ex vivo HS are available. We aimed to compare Thulium Fiber Laser (TFL) and Holmium:YAG (Ho:YAG)'s LE and define the most accurate LE parameter.

METHODS

Hard and soft homogenous- and heterogenous-AS (Ho-AS, He-AS) were made to reproduce calcium-oxalate monohydrate and uric acid stones, respectively by a rapid or slow brewing of BegostonePlus (Bego) and distilled water. One hundred and fifty and 272μm-laser fibers, connected to 50W-TFL and 30W-HoYAG generators, compared three settings for TFL (FD: 0.15J/100Hz; D: 0.5J/30Hz; Fr: 1J/15Hz) and two for Ho:YAG (D-Fr). An experimental setup consisted in immerged 10mm cubic stone phantoms with a 20 seconds' lasing spiral, in contact mode, repeated four times. Stones were dried, weighted and μ-scanned (ablation weight and volume [AW and AV]).

RESULTS

With He-AS, dusting AV were four- and three-fold higher with TFL compared to Ho:YAG against hard and soft (P<0.05). In fragmentation, AV were two-fold higher with TFL compared to Ho:YAG against hard (P<0.05) and soft (P<0.05). Experiments with Ho-AS were associated with non-significant differences when comparing TFL-150μm and TFL-272μm. The ablation weight-volume correlation coefficients was higher with Ho-AS than with He-AS (P<0.0001), and with hard than soft AS. If the LE can be estimated by the AW with hard AS, this approximation is not consistent for soft AS.

CONCLUSION

TFL presented higher ablation rates than Ho:YAG, significant with He-AS. If the AW is acceptable and less expensive for hard Ho-AS, AV are more accurate for He-AS, which are suggested to imitate closely HS.

Chemical Composition, Antioxidant Potentials, and Calcium Oxalate Anticrystallization Activity of Polyphenol and Saponin Fractions from Argania spinosa L. Press Cake

A wide range of biological properties and a potent therapeutic and prophylactic effect on chronic diseases are all present in Argania spinosa L. press cake. The aim of this research is to valorize the anticrystallization properties against calcium oxalate crystals of Argania spinosa L. press cake fractions and identify its bioactive components. Chemical species identification was performed using GC–MS analysis. The turbidimetric model was used to investigate crystallization inhibition in vitro. Infrared spectroscopy technique was used to characterize the synthesized crystals. Furthermore, both DPPH and FRAP methods were used to assess antioxidant activity. The results show that the fractions are equally important in crystallization inhibition percentages of calcium oxalate crystals. For saponin and polyphenol fractions, the inhibition percentages are in the orders of 83.49% and 82.83%, respectively. The results of the antioxidant activity by DPPH method show that the two fractions are equally important in the elimination of free radicals; the inhibition percentages were 77.87 ± 4.21 and 89.92 ± 1.39 for both polyphenols and saponins, respectively. FRAP method showed that the absorbance increases proportionally with concentration, and the absorbance are almost similar for both fractions and reach maximum values in the orders of 0.52 ± 0.07 and 0.42 ± 0.03, respectively, for saponins and polyphenols. These findings demonstrate that both fractions are rich in bioactive chemicals and have an anticrystallization capacity, allowing them to be employed for the curative and prophylactic effects against urolithiasis.

Prevalence and trends of urolithiasis among adults

PURPOSE OF REVIEW

The purpose of this article is to review and synthesize the current literature on the epidemiology of urolithiasis.

RECENT FINDINGS

The global patterns of urolithiasis are changing, as the prevalence of urolithiasis appears to be increasing across the world. Geographical variation in the prevalence of urolithiasis is noted across countries and within each country. Although urolithiasis is more common among men and white race, recent data suggests a more prominent rise in the prevalence among women and African Americans. Yet, no conclusive explanations for these phenomena are reported so far.

SUMMARY

Urolithiasis is a highly prevalent condition with an increasing prevalence among women as compared with men closing the gender gap in urolithiasis. Further studies are needed to identify the potential causes for this observation.

Laser Fiber Displacement Velocity during Tm-Fiber and Ho:YAG Laser Lithotripsy: Introducing the Concept of Optimal Displacement Velocity

BACKGROUND

Endocorporeal laser lithotripsy (EL) during flexible ureteroscopy (URS-f) often uses "dusting" settings with "painting" technique. The displacement velocity of the laser fiber (LF) at the stone surface remains unknown and could improve EL's ablation rates. This in vitro study aimed to define the optimal displacement velocity (ODV) for both holmium:yttrium-aluminium-garnet (Ho:YAG) and thulium fiber laser (Tm-Fiber).

METHODS

A 50W-TFL (IRE Polus^®, Moscow, Russia) and a 30W-MH1-Ho:YAG laser (Rocamed^®, Signes, Provence-Alpes-Côte d'Azur, France), were used with 272 µm-Core-Diameter LF (Sureflex, Boston Scientific^©, San Jose, CA, USA), comparing three TFL modes, "fine dusting" (FD: 0.05-0.15 J/100-600 Hz); "dusting" (D: 0.5 J/30-60 Hz); "fragmentation" (Fr: 1 J/15-30 Hz) and two Ho:YAG modes (D: 0.5 J/20 Hz, Fr: 1 J/15 Hz). An experimental setup consisting of immerged cubes of calcium oxalate monohydrate (COM) stone phantoms (Begostone Plus, Bego^©, Lincoln, RI, USA) was used with a 2 s' laser operation time. LF were in contact with the stones, static or with a displacement of 5, 10 or 20 mm. Experiments were repeated four times. Stones were dried and µ-scanned. Ablation volumes (mm³) were measured by 3D-segmentation.

RESULTS

ODV was higher in dusting compared to fragmentation mode during Ho:YAG lithotripsy (10 mm/s vs. 5 mm/s, respectively). With Tm-Fiber, dusting and fragmentation OVDs were similar (5 mm/s). Tm-Fiber ODV was lower than Ho:YAGs in dusting settings (5 mm/s vs. 10 mm/s, respectively). Without LF displacement, ablation volumes were at least two-fold higher with Tm-Fiber compared to Ho:YAG. Despite the LF-DV, we report a 1.5 to 5-fold higher ablation volume with Tm-Fiber compared to Ho:YAG.

CONCLUSIONS

In dusting mode, the ODV^Tm-Fiber is lower compared to ODV^Ho:YAG, translating to a potential easier Tm-Fiber utilization for "painting" dusting technique. The ODV determinants remain unknown. Dynamic ablation volumes are higher to static ones, regardless of the laser source, settings or LF displacement velocity.

Study of risk factor of urinary calculi according to the association between stone composition with urine component

Urolithiasis is a common urinary disease with high recurrence. The risk factor for the recurrence of calculi is not very clear. The object of the present study was to evaluate the association between calculi composition and urine component and analyse the risk factor for the recurrence of urolithiasis. In this study, a total of 223 patients with calculi and healthy control were enrolled, and the components of the calculi and urina sanguinis collected before surgery were analysed. Of the 223 patients, 157 were males and 66 were females. According to the stone composition, the case group was subdivided into three groups. 129 patients had single calcium oxalate stones, 72 had calcium oxalate stones mixed with other stones and 22 had other type of stones excluding calcium oxalate stones. Urine biochemicals were analysed and the associations were found between the chemicals in each group. Multivariate logistic analysis demonstrated that reduced urinary magnesium and uric oxalic acid were independent risk factors when comparing all cases with normal controls. Only decreased urinary magnesium was found to be a risk factor comparing the single calcium oxalate group with normal control group. Low level of urinary magnesium and uric oxalic acid were found to be risk factors comparing the mixed calcium oxalate group with normal control group. No risk factor was found comparing the other stone group with normal control group. In conclusion, there were clear relationships between stone components and urine chemicals. Urine chemicals might be risk factors to predicate the occurrence of urolithiasis.

Evaluation of a free 3D software for kidney stones' surgical planning: "kidney stone calculator" a pilot study

Introduction

Kidney Stone Calculator (KSC) is a free, three-dimensional (3D) planning software for flexible ureteroscopy(fURS) with Holmium:YAG(Ho:YAG) endocorporeal lithotripsy (EL). KSC provides the stone volume (SV) and expected duration of lithotripsy (ExDL) estimations based on non-enhanced-CT scan (NECT) DICOM series. We aimed to provide a preclinical and clinical evaluation of KSC.

Patients and methods

A preclinical evaluation measured the SV by three operators (resident, endourology expert and research engineer) among 17 NECT cases. Between January and March 2020, a multicentric, prospective, observational double-blind clinical evaluation was conducted in patients presenting with renal stones treated with Ho:YAG-EL during fURS and preoperative NECT. Demographic and surgical data were collected. The primary endpoint was a significant median difference between ExDL and EffectiveDL (EfDL). Second, efficiency (J/mm³) and efficacy (mm³/min) ratios were calculated.

Results

The preclinical evaluation showed no significant difference in the SV measurements among operators (p > 0.05). Pearson and Kendall coefficients of 0.99 and 0.98, respectively, were found. Twenty-six patients were included in the clinical evaluation, with a median age of 55 years. In 66% of cases, there was a single stone located in the lower pole, with a density > 1000 Hounsfield Unit observed in 42% and 85% of cases. A 14% [Q1–Q3 (5.4–24.8); p = 0.36] median difference between ExDL and EfDL was noted, which was greater in the case of lower pole stones with no possible relocation (p = 0.008). Median values of 17.6 J/mm³ and 0.4 (0.32–0.56) mm³/s EL were also noted.

Conclusions

Kidney Stone Calculator is a reproducible and accurate software that allows for an estimation of the stone burden and provides an ExDL for URSf. Defining the influencing factors of EL will improve its ExDL.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00345-021-03671-z.