Recent advances in understanding and managing urolithiasis

Molecular insights into cell signaling pathways in kidney stone formation

Urolithiasis, or kidney stones, has emerged as a significant public health concern. Despite this, effective treatments targeting stone formation and recurrence are limited. This review delves into the molecular mechanisms underlying the condition. Investigating these molecular aspects can address existing gaps in treatment options. Future research can uncover new therapeutic strategies by targeting downstream pathways, and effector molecules. Cell signaling pathways offer potential targets, as they involve complex interactions that can be modulated to address multiple clinical symptoms. An imbalance in calcium and oxalate levels can lead to kidney stone formation which is characterized by oxidative stress, inflammation, and cell death. The interplay between key organelles like the endoplasmic reticulum and mitochondria triggers stress pathways, including oxidative stress and apoptosis. This review consolidates recent advances in understanding the pathophysiology and signaling events associated with kidney stones.

Comparison of holmium:yttrium-aluminium-garnet (YAG), thulium fiber laser, and pulsed thulium:YAG lasers on soft tissue: an ex vivo study

OBJECTIVES

To assess laser-tissue interactions through ablation, coagulation, and carbonisation characteristics in a non-perfused porcine kidney model between three pulsed lasers: holmium (Ho): yttrium-aluminium-garnet (YAG), thulium fiber laser (TFL), and pulsed thulium (p-Tm):YAG.

MATERIALS AND METHODS

A 150-W Ho:YAG, a 60-W TFL, and a 100-W p-Tm:YAG lasers were compared. The laser settings that can be set identically between the three lasers and be clinically relevant for prostate laser enucleation were identified and used on fresh, unfrozen porcine kidneys. Laser incisions were performed using stripped laser fibers of 365 and 550 μm, set at distances of 0 and 1 mm from the tissue surface at a constant speed of 2 mm/s. Histological analysis evaluated shape, depth, width of the incision, axial coagulation depth, and presence of carbonisation.

RESULTS

Incision depths, widths, and coagulation zones were greater with Ho:YAG and p-Tm:YAG lasers than TFL. Although no carbonisation was found with the Ho:YAG and p-Tm:YAG lasers, it was common with TFL, especially at high frequencies. The shapes of the incisions and coagulation zones were more regular and homogeneous with the p-Tm:YAG laser and TFL than with Ho:YAG laser. Regardless of the laser used, short pulse durations resulted in deeper incisions than long pulse durations. Concerning the distance, we found that to be effective, TFL had to be used in contact with the tissue. Finally, 365-μm fibers resulted in deeper incisions, while 550-μm fibers led to wider incisions and larger coagulation zones.

CONCLUSION

Histological analysis revealed greater tissue penetration with the p-Tm:YAG laser compared to the TFL, while remaining less than with Ho:YAG. Its coagulation properties seem interesting insofar as it provides homogeneous coagulation without carbonisation, while incisions remained uniform without tissue laceration. Thus, the p-Tm:YAG laser appears to be an effective alternative to Ho:YAG and TFL lasers in prostate surgery.

Adherence to guidelines in the management of urolithiasis: are there differences among distinct patient care settings?

INTRODUCTION

Urolithiasis is a common diagnosis in urology. New technologies offer a variety of diagnostic and therapy and consequently display a financial burden on healthcare systems. Hence, clinical practice guidelines (CPG) are essential to implement evidence-based medicine and assure a standard of care considering limited resources. To date, there is no evidence of the use and adherence to CPG on urolithiasis.

MATERIAL AND METHODS

Therefore, we performed a cross-sectional study to analyze the use of CPG on urolithiasis. Data collection was carried out by a questionnaire given to 400 German urologists. The survey included use and adherence to guidelines, evaluation of the clinical situation, therapy spectrum, and workplace. In total, 150 (37%) questionnaires were received and included in our survey. Statistics were performed by SPSS using Chi-quadrat test/Fisher's exact test.

RESULTS

In our study, urologists were office based, hospital affiliated, non-academic, or academic centers in 53%, 32%, 16% and 5%, respectively. In 74% and 70%, urologists adhere to CPG in diagnostic and therapy. Interestingly, workplace and therapy spectrum determines the use of different CPG (p = 0.01; p = 0.022). Academic urologists were more likely to use international CPG of EAU (40%), while outpatient urologists significantly orientated on national CPG (46%). 86% of urologists with high volume of urolithiasis practice interventions in contrast to 53% in low volume (p = 0.001). More than 80% of urologists use short versions and app version of CPG.

CONCLUSION

We firstly describe compliance and the use of CPG on urolithiasis. EAU and DGU present the most commonly used CPG. Short version and app version of CPG find frequent clinical utilization.

Medical evaluation and pharmacotherapeutical strategies in management of urolithiasis

Treatment of urolithiasis depends on several important factors which include stone location, size, composition, and patient symptoms. Although significant advancements have been made in the surgical management of urolithiasis in the last decade, pharmacotherapy which can prevent the formation of new stones and decrease the recurrence of urolithiasis has not experienced the same level of success. Currently, urolithiasis is regarded as a complicated syndrome that is determined by numerous factors, and any treatment plan for urolithiasis should be individualized while considering any potential damage arising from stone-forming factors. This review introduces the most popular methods currently used to evaluate urolithiasis and the pharmacotherapy of urolithiasis based on patient-specific factors.

Chronomics of Circulating Plasma Lipid Peroxides and Antioxidant Enzymes in Renal Stone Formers

The chronome of lipid peroxidation and anti-oxidant defense mechanisms may relate to the efficacy and management of time qualified preventive therapeutic and dietary interventions. One hundred renal stone patients, 20-60 years of age, and 50 clinically healthy volunteers, 21-45 years, were synchronized for 1 week with diurnal activity from 06:00 to 22:00 and nocturnal rest. All subjects took their usual meals three times daily (breakfast around 08:30, lunch around 13:00, and dinner around 20:30) with usual fluid intake. Drugs known to affect free radical system were not taken. Blood samples were collected at 6-h intervals for 24-h under standardized, presumably 24-h synchronized conditions. Determinations included plasma lipid peroxides, in terms of malondialdehyde (MDA) and blood superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and catalase (CAT) activities. A marked circadian variation was demonstrated for each studied variable by population-mean cosinor in renal stone patients and healthy participants (p < 0.001). By comparison to healthy subjects, parameter tests indicate that the stone formers had a higher MESOR of MDA, but a lower MESOR of SOD, GPx, GR and CAT. Furthermore, the patients also differed from the healthy controls in terms of their circadian amplitude and acrophase (tested jointly) of all variables (p < 0.001). Mapping the broader time structure with multifrequency circadian characteristics of oxidants and anti-oxidants is needed for exploring their role as marker in the treatment and management of urolithiasis.

The lipid peroxidation in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy

AIM

To evaluate the level of lipid peroxidation in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy (ESWL).

MATERIALS & METHODS

Isoprostane concentration (8-isoPGF_2α) was measured in urine, and thiobarbituric acid reactive substance production in serum and erythrocytes. In addition, the concentrations of selected compounds (uric acid, glucose and creatinine) were measured in serum.

RESULTS

The patients (before and after ESWL) demonstrated significantly higher levels of two different biomarkers of lipid peroxidation compared with the control group. A correlation was identified between increased amounts of uric acid and biomarkers of lipid peroxidation in patients with nephrolithiasis, both before and after ESWL.

CONCLUSION

Uric acid may be associated with lipid peroxidation in patients with nephrolithiasis.

Extracorporeal shock wave lithotripsy under intravenous sedation for treatment of urolithiasis

BACKGROUND

In contrast to treatment with oral or intramuscular analgesics, extracorporeal shock wave lithotripsy (E.S.W.L.) can be performed with patients under sedation too. Besides the advantage of increased shock energy, patients tend to have more constant breathing excursions and are more idle during treatment, potentially increasing the stone-free ratio (S.F.R.) after treatment.

METHODS

This study presents the results of 310 patients who underwent 400 E.S.W.L. procedures under sedation, with a stationary lithotripter.

RESULTS

After one procedure, the S.F.R. was 54.8% (170/310). A second treatment was successful in 42.1% (32/76), a third treatment in 21.4% (3/14). Therefore, 66.1% (205/310) of patients eventually became stone-free. Kidney stones were successfully treated in 65.4% (161/246), ureteral stones in 68.8% (44/64) of cases. Patients with stones ≤15 mm were successfully treated in 67.4% (194/288), patients with stones >15 mm in 50% (11/22) of cases. Considering each procedure individually, 45.3% (181/400) of procedures were successful after 3 weeks. Extending follow-up to 3 months is important, since 26.7% of stones (24/90) eventually still disappeared, increasing S.F.R. to 51.3% after one procedure. Complications occurred after 5.5% E.S.W.L.-procedures.

CONCLUSIONS

E.S.W.L. is a well-tolerated, non-invasive procedure that produces reasonable stone clearance of both upper and lower urinary tract calculi. Performing the procedure whilst patients are intravenously sedated results in an acceptable S.F.R. Strong selection based on unfavourable factors could increase the chance on successful treatment and spare patients a pointless procedure. However, considering E.S.W.L.'s elegant nature, sometimes a more tolerant approach seems justifiable.