Seminal papers in urology: urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study : Borghi L, Meschi T, Amato F, Briganti A, Novarini A, Giannini A. urinary volume, water and recurrences in idiopathic calcium nephrolithiasis: a 5-year randomized prospective study. The Journal of urology. 1996 Mar;155(3):839 - 43

Kidney stones, a persistent urological condition, continue to affect people globally. In this critical review, we examine the work of Borghi et al. who evaluated patients with idiopathic stone formation and randomised 99 patients to increased water intake (≥ 2 L/day) and 100 patients to usual care in a 5-year randomized controlled trial. The study examined baseline urine volume in individuals with idiopathic calcium stones, recurrence rates, and relevant biochemical factors. The study found reduced recurrence rate (12.1% vs. 27% (p = 0.008)), and time to recurrence with increased water intake (38.7 ± 13.2 months) vs. (25 ± 16.4 months) (p = 0.016). These findings inform clinical practice, contributing to the guideline recommendations that kidney stone patients should aim for fluid intake of at least 2.5 L per day to prevent stone recurrence.

Correlation between sKL and Nrf2 plasma levels and calcium oxalate urolithiasis

OBJECTIVE

To investigate the relationship between plasma levels of sKL and Nrf2 and calcium oxalate calculi.

METHODS

The clinical data of 135 patients with calcium oxalate calculi treated in the Department of Urology of the second affiliated Hospital of Xinjiang Medical University from February 2019 to December 2022, and 125 healthy persons who underwent physical examination in the same period were collected and divided into healthy group and stone group. The levels of sKL and Nrf2 were measured by ELISA. Correlation test was used to analyze the risk factors of calcium oxalate stones, logistic regression analysis was used to analyze the risk factors of calcium oxalate stones, and ROC curve was used to evaluate the sensitivity and specificity of sKL and Nrf2 in predicting urinary calculi.

RESULTS

Compared with the healthy group, the plasma sKL level in the stone group decreased (111.53 ± 27.89 vs 130.68 ± 32.51), while the plasma Nrf2 level increased (300.74 ± 114.31 vs 246.74 ± 108.22). There was no significant difference in the distribution of age and sex between the healthy group and the stone group, but there were significant differences in plasma levels of WBC, NEUT, CRP, BUN, BUA, SCr, BMI, and eating habits. The results of correlation test showed that the level of plasma Nrf2 was positively correlated with SCr (r = 0.181, P < 0.05) and NEUT (r = 0.144 P < 0.05). Plasma sKL was not significantly correlated with Nrf2 (r = 0.047, P > 0.05), WBC (r = 0.108, P > 0.05), CRP (r = - 0.022, P > 0.05), BUN (r = - 0.115, P > 0.05), BUA (r = - 0.139, P > 0.05), SCr (r = 0.049, P > 0.05), and NEUT (r = 0.027, P > 0.05). Plasma Nrf2 was not significantly correlated with WBC (r = 0.097, P > 0.05), CRP (r = 0.045, P > 0.05), BUN (r = 0.122, P > 0.05), and BUA (r = 0.122, P > 0.05); (r = 0.078, P > 0.05) had no significant correlation. Logistic regression showed that elevated plasma sKL (OR 0.978, 95% CI 0.969 ~ 0.988, P < 0.05) was a protective factor for the occurrence of calcium oxalate stones, BMI (OR 1.122, 95% CI 1.045 ~ 1.206, P < 0.05), dietary habit score (OR 1.571, 95% CI 1.221 ~ 2.020, P < 0.05), and WBC (OR 1.551, 95% CI 1.423 ~ 1.424, P < 0.05). Increased NEUT (OR 1.539, 95% CI 1.391 ~ 1.395, P < 0.05) and CRP (OR 1.118, 95% CI: 1.066 ~ 1.098, P < 0.05) are risk factors for the occurrence of calcium oxalate stones.

CONCLUSION

Plasma sKL level decreased and Nrf2 level increased in patients with calcium oxalate calculi. Plasma sKL may play an antioxidant role in the pathogenesis of calcium oxalate stones through Nrf2 antioxidant pathway.

A Novel Infrared Spectroscopy Method for Analysis of Stone Dust for Establishing Final Composition of Urolithiasis

Background

The introduction of the holmium laser for lithotripsy and minimally invasive techniques in endoscopy increased the popularity of stone dusting techniques. Retrieving stone pieces for an analysis increases the economic burden of surgery and operative time. Novel methods are needed for the analysis of convenient urolithiasis composition.

Objective

This study aims to assess the efficacy of the stone dust Fourier transform infrared spectroscopy coupled with attenuated total reflection (FTIR ATR) method for accurate stone composition determination from the dust specimens compared with simultaneously retrieved standard stone fragments.

Design setting and participants

From July 2021 to March 2022, a total of 75 patients who received endoscopic treatment for urolithiasis were included in this study.

Outcome measurements and statistical analysis

The accuracy of the FTIR ATR method was assessed via estimates of sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV). The results were compared between samples of stone dust and the final stone composition.

Results and limitations

Total or partial biochemical composition agreement was observed in 92.7% of cases and total agreement in 82.4% of cases when stone dust was compared with stone fragments. The highest accuracy rates were obtained for uric acid stones: sensitivity 100%, specificity 98.3%, PPV 90.9%, and NPV 100%. Identification of other types of stones was also of high accuracy, reaching up to 83.3% sensitivity and 100% specificity.

Conclusions

The application of FTIR ATR spectroscopy for a stone dust analysis allows obtaining easy and cost-effective final composition of urolithiasis without a stone fragment analysis. This technique was shown to be feasible, and there is substantial potential for clinical practice.

Patient summary

This study investigates a novel method that determines accurate stone composition without acquiring the pieces of stone during surgery. The results have shown that stone dust Fourier transform infrared spectroscopy coupled with attenuated total reflection provides accurate stone composition.

Ex vivo study: is it possible to overcome the blurriness caused by holmium laser fragmentation of kidney stones?

Better endoscopic vision is mandatory for successful ureteroscopic stone operations to achieve shorter operating time. However, an important impairing factor for a good endoscopic view is the cloudiness of vision which was formed during laser fragmentation. Holmium laser fragmentation of calcium oxalate stones produces calcium carbonate solubility of which is dependent on pH, citrate, and phosphate. In this ex vivo research, the solubility of calcium carbonate has been investigated in solutions composed of various concentrations of citrate and phosphate buffered at different pH levels after laser fragmentation of calcium oxalate stones. Calcium oxalate stones were placed into the laboratory tubes filled with various concentrations of citrate-phosphate buffers with different pH values. Laser energy in dusting mode was applied to the stones and spectrophotometric measurement for optical density (OD) was calculated for each buffered solution for clarity comparison. In the first phase, solutions composed of four different molar concentrations of citrate-phosphate buffer (0.2, 0.3, 0.4 and 0.5 molars) at various pH levels were used. Then, the next phase of the study was designed to compare solutions demonstrating the lowest OD values with an isotonic saline solution. The results were most convenient at 0.5 molarity (pH = 6) followed by 0.4 molarity (pH = 7) in the first phase (OD values of 0.054 and 0.065, respectively). In the next phase, OD values of both buffered solutions were significantly lower than those of isotonic saline solution (p = 0). Two specific buffers have provided better optic visibility values after laser fragmentation supporting their use as an irrigation solution for the favor of less cloudiness.

Hydroxycitrate prevents calcium oxalate crystallization and kidney injury in a nephrolithiasis rat model

Hydroxycitrate (HCA) is a derivative of citric acid, and previous studies of HCA have revealed its ability to inhibit the formation of calcium oxalate crystals in vitro. To date, there has been little evidence proving that HCA has the same effectiveness in vivo. The present study was designed to investigate the ameliorating effect of HCA on calcium oxalate deposition and renal impairment in a male rat model. Male Sprague-Dawley rats were randomly divided into four groups: a control group, a model group (glyoxalic acid), a CA group (glyoxalic acid + CA), and an HCA group (glyoxalic acid + HCA). Kidney stone formation was induced by injection of glyoxalic acid (60 mg/kg). The results showed that serum and urinary parameters were significantly improved by HCA treatment. In addition, differences in the formation of calcium oxalate crystals between groups were observed, and HCA was superior to CA in inhibiting crystal accumulation. The ultrastructure of renal tubules and glomeruli occurred in the model group, and the above lesions were significantly reduced in the HCA group. Both OPN and SOD expression levels were promoted by HCA, while CA only promoted OPN. In this article, we provided data on whether HCA affected kidney stones and the expression levels of OPN and SOD in a male rat model.

hydrochlorothiazide to reduce urinary calcium excretion in calcium oxalate stone patients with hypercalciuria: a prospective randomized study

PURPOSE

Calcium oxalate (Ca-Ox) is the most common stone composition and one of the most common 24-h urine anomalies is hypercalciuria. The purpose of this study was to evaluate the efficacy of potassium citrate (K-CIT) for prevention of hypercalciuria in comparison with hydrochlorothiazide (HCT) in patients with calcium oxalate stones and hypercalciuria.

MATERIALS AND METHODS

In this prospective randomized study, patients were randomized to receive either HCT (50 mg/day) or K-CIT (40 mEq/day) following achieving stone-free status. Treatment was continued for 6 months. 24 h urine analysis was performed prior to treatment and repeated at third month and measured parameters were volume, calcium, oxalate, citrate, sodium, and uric acid. Stone recurrence was evaluated with KUB and ultrasonography at 6th and 12th months.

RESULTS

Data of 40 patients in each arm were evaluated. Mean 24 h urine calcium levels decreased to 205 ± 54.5 mg/day and 220.6 ± 96.3 mg/day in the K-CIT and HCT groups, respectively, and difference was not significant (p = 0.931). The reduction compared to pretreatment values was statistically significant in both groups. Urinary citrate levels also significantly increased in both groups and level of increase was significantly higher in K-CIT group. At 12th month, ultrasonography revealed stones in two patients in HCT group, and in one patient in the K-CIT group.

CONCLUSIONS

K-CIT provided significantly reduced calcium and increased citrate excretion in patients Ca-Ox stone patients with hypercalciuria. The efficacy in decreasing calcium excretion was comparable to HCT treatment. K-CIT can be used for medical prophylaxis of Ca-OX stone patients with hypercalciuria.

Association between metabolic syndrome and calcium oxalate stone risk in Chinese individuals: a nomogram prediction model

Objective

This retrospective study explored the association between calcium oxalate (CaOx) stones and metabolic syndrome. It also developed and validated a nomogram to aid in the prediction of CaOx stones.

Methods

This case-control study enrolled 150 patients with CaOx stones and 635 individuals without urolithiasis from October 2016 to October 2018. Student’s t-test, the chi-squared test, and logistic univariate and multivariate regression analyses were used. A nomogram for prediction of CaOx stones was established based on independent associated factors. The concordance index and calibration curves were plotted to determine nomogram accuracy.

Results

Female sex, age ≥66 years, blood pressure (systolic pressure ≥130 mmHg and/or diastolic pressure ≥85 mmHg), and blood uric acid level independently influenced the risk of CaOx stones, according to multivariate logistic regression analysis; these factors were included in the nomogram. The concordance index was 0.701 (95% confidence interval: 0.658–0.737). The standard curve showed a robust fit with the calibrated predictive curve.

Conclusions

Female sex, age ≥66 years, elevated blood pressure, and blood uric acid level independently influenced the risk of CaOx stones. Our nomogram for the prediction of CaOx stones may provide a clinical basis for the assessment of CaOx stone and facilitate early prevention efforts.

P38 MAPK signaling pathway mediates COM crystal-induced crystal adhesion change in rat renal tubular epithelial cells

The objective of the study is to clarify the mechanism of p38 mitogen-activated protein kinase (p38 MAPK) signaling pathway in the change of crystal adhesion in rat renal tubular epithelial cells (NRK-52E) induced by calcium oxalate monohydrate (COM) crystals. NRK-52E cells were divided into COM crystal-treated group and control group according to whether the cell culture medium contains different concentrations of COM crystals. The concentrations of lactate dehydrogenase in the both group medium were determined after being cultured for 24 h. Protein and RNA were extracted from both cell groups after being cultured at different time points. SB239063, an inhibitor of the activation of p38 MAPK, was pretreated for 2 h before incubation with COM crystals. Western blotting and RT-qPCR were performed to confirm the expression levels of relative genes. All the experimental results were summarized and analyzed by SPSS 20.0 statistical analysis software. COM crystals (146 µg/cm²) could induce the expression levels of NLRP3, caspase-1 and interleukin-1β (IL-1β) significantly increased in NRK-52E cells. Compared with the control group cells, the transcription and translation levels of p38 MAPK-related molecule (such as p-p38) and adhesion molecules (such as osteopontin, hyaluronic acid and CD44) were significantly increased in COM crystal-treated cells and can be inhibited by SB239063 and NLRP3 gene silencing. This study demonstrated that the p38 MAPK signaling pathway mediated the COM crystal-induced crystal adhesion change in NRK-52E cells and required the involvement of NLRP3 inflammasome.

Autophagy inhibition attenuates hyperoxaluria-induced renal tubular oxidative injury and calcium oxalate crystal depositions in the rat kidney

Hyperoxaluria-induced oxidative injury of renal tubular epithelial cell is a casual and essential factor in kidney calcium oxalate (CaOx) stone formation. Autophagy has been shown to be critical for the regulation of oxidative stress-induced renal tubular injury; however, little is known about its role in kidney CaOx stone formation. In the present study, we found that the autophagy antagonist chloroquine could significantly attenuate oxalate-induced autophagy activation, oxidative injury and mitochondrial damage of renal tubular cells in vitro and in vivo, as well as hyperoxaluria-induced CaOx crystals depositions in rat kidney, whereas the autophagy agonist rapamycin exerted contrasting effects. In addition, oxalate-induced p38 phosphorylation was significantly attenuated by chloroquine pretreatment but was markedly enhanced by rapamycin pretreatment, whereas the protective effect of chloroquine on rat renal tubular cell oxidative injury was partly reversed by a p38 protein kinase activator anisomycin. Furthermore, the knockdown of Beclin1 represented similar effects to chloroquine on oxalate-induced cell oxidative injury and p38 phosphorylation in vitro. Taken together, our results revealed that autophagy inhibition could attenuate oxalate-induced oxidative injury of renal tubular cell and CaOx crystal depositions in the rat kidney via, at least in part, inhibiting the activation of p38 signaling pathway, thus representing a novel role of autophagy in the regulation of oxalate-induced renal oxidative injury and CaOx crystal depositions for the first time.

Effect of Blumea balsamifera extract on the phase and morphology of calcium oxalate crystals

Objective

Calcium oxalate crystals are found in majority of kidney stones with calcium oxalate monohydrate (COM) as one of the primary types of kidney stones. Various methods of treatment exist, including herbal treatment in the Philippines that uses the medicinal herb Blumea balsamifera (B. balsamifera).

Methods

The effect of B. balsamifera extract on the morphology of calcium oxalate crystals was studied by light microscopy, image analysis, powder X-ray diffraction and scanning electron microscopy.

Results

The extract decreased the crystal size by 5.22%–82.62% depending on the degree of supersaturation. Through analysis of the projected area of the crystals, the extract was found to shift the phase of the crystals from COM to calcium oxalate dihydrate (COD). This shift in phase is significant with a COM to COD shift of 88.26% at 0.5 mg/mL of extract and 91.53% at 1.0 mg/mL of extract. Scanning election microscopic (SEM) images revealed aggregation of crystals at 0 mg/mL of extract. At 1.0 mg/mL of extract, the scanning electron micrographs showed discernible crystal unit boundaries.

Conclusion

B. balsamifera extract was observed to have decreased crystal size, shifted crystal phase from COM to COD and prevented the aggregation of calcium oxalate crystals.

Beneficial effect of Citrus limon peel aqueous methanol extract on experimentally induced urolithic rats

CONTEXT

Citrus limon (L.) Burm.f. (Rutaceace) is a commonly available fruit variety with high medicinal and industrial values.

OBJECTIVE

Lemon peel (LP) extract was studied as a potent preventive and curative agent for experimentally induced hyperoxaluric rats.

MATERIALS AND METHODS

Gas chromatography-mass spectrometry (GC-MS) analyses and toxicity study were performed for aqueous methanol LP extract. Twenty-four Wistar rats were segregated into four groups. Group 1: Control; Group 2: Urolithic (ethylene glycol (EG) - 0.75%); Group 3: Preventive study (EG + LP extract administration from 0th to 7th week); Group 4: Curative study (EG + LP extract administration from 4th to 7th week). Animals received LP extract daily by oral administration (100 mg/kg body weight) for 7 weeks.

RESULTS AND DISCUSSION

GC-MS analyses revealed that compound 6 was abundant in the LP extract (32%) followed by compound 1 (∼21%). The LD50 value of LP extract was found to be >5000 mg/kg of body weight. Urolithic rats showed significantly higher urinary calcium and oxalate (4.47 ± 0.44 and 18.86 ± 0.55 mg/24 h, respectively) excretion compared with control and experimental rats. Renal function parameters like urea (84 ± 8.5 and 96.1 ± 3.6 mg/dL), creatinine (1.92 ± 0.27 and 1.52 ± 0.22 mg/dL), and urinary protein (2.03 ± 0.02 and 2.13 ± 0.16 mg/24 h) were also reduced by LP extract (p < 0.001) and corroborated with tissue analyses (SOD, catalase, and MDA levels) and histological studies in normal and experimental animals. Immunohistochemical staining of THP and NF-κB in urolithic animals showed elevated expression than the control, while LP extract suppressed the expression of these proteins.

CONCLUSION

In conclusion, lemon peel is effective in curing kidney stone disease and also can be used to prevent the disease and its recurrence.