Search Results (46)

Nephrolithiasis is a prevalent urological disorder worldwide, whose pathogenesis involves a complex network of crystal formation, cellular injury, and microenvironmental dysregulation. As a critical mechanism for regulating cellular functions, protein post-translational modifications (PTMs) have been increasingly implicated in multiple facets of kidney stone formation, including crystal–cell interactions, oxidative stress responses, and inflammatory signaling pathways. This review systematically synthesizes the biochemical foundations of PTMs, the molecular microenvironment of nephrolithiasis, and the roles of key modifications such as phosphorylation and acetylation in the pathogenesis of calculi. It further explores the translational potential of PTM detection technologies in clinical practice. Current evidence indicates that PTMs influence the nucleation, growth, and aggregation of crystals by modulating the activity of pro-/anti-lithogenic proteins, the expression of cell adhesion molecules, and inflammatory pathways. Consequently, therapeutic strategies targeting PTMs may offer novel avenues for the prevention and management of kidney stones. Future research should focus on integrating multi-omics approaches with functional validation to elucidate the dynamic regulatory networks of PTMs within the stone microenvironment, thereby advancing the development of precision medicine. Full article

Aim: To explore the association between urinary stone cultures and infectious complications following PCNL. Materials and Methods: An observational case–control study was conducted in patients undergoing PCNL. The assessment included demographic parameters, medical history, urinalysis, and urine culture and blood testing. Pre-operatively, urinary stone samples were collected for cultures. Post-operatively, patients were observed for infectious complications such as fever and/or SIRS. Patients were divided into two groups based on the presence or absence of infected renal calculi. Patient characteristics, stone factors, and intra-operative and post-operative findings were studied in relation to stone culture. Descriptive statistics was used to present the data and the SPSS software was used for analysis. Results: From December 2023 to March 2025, a total of 126 patients were included in the study. A total of 16 patients (12.6%) had a positive stone culture. Statistical significance was found upon the comparison of stone culture with gender (p = 0.046), chronic kidney disease (p = 0.002), pre-operative urine culture (p = 0.001), pre-operative haemoglobin (g/dL) (<0.001), pre-operative S. creatinine (mg/dL) (p = 0.038), stone volume (mm³) (p = 0.012), CROES score (p = 0.023), SIRS (p = 0.001), and AKI (p = 0.021). Conclusions: Infected renal calculi identified by positive stone cultures were strongly associated with infective complications such as fever and SIRS following PCNL. E. Coli was the dominant bacteria present in both bladder urine and renal stone culture. The occurrence of infectious complications despite the administration of pre-operative antibiotics highlights the antibiotic resistance patterns noted among the cultured bacteria. The pre-operative factors identified to be associated with a positive stone culture could potentially be used for predicting infected stones, thereby improving outcomes. Full article

This retrospective diagnostic accuracy study compared radiologist-based qualitative assessments and radiomics-based analyses with an automated artificial intelligence (AI)–based volumetric approach for evaluating changes in kidney stone burden on follow-up CT examinations. With institutional review board approval, 157 patients (mean age, 61 ± 13 years; 99 men, 58 women) who underwent baseline and follow-up non-contrast abdomen–pelvis CT for kidney stone evaluation were included. The index test was an automated AI-based whole-kidney and stone segmentation radiomics prototype (Frontier, Siemens Healthineers), which segmented both kidneys and isolated stone volumes using a fixed threshold of 130 Hounsfield units, providing stone volume and maximum diameter per kidney. The reference standard was a threshold-defined volumetric assessment of stone burden change between baseline and follow-up CTs. The radiologist’s performance was assessed using (1) interpretations from clinical radiology reports and (2) an independent radiologist’s assessment of stone burden change (stable, increased, or decreased). Diagnostic accuracy was evaluated using multivariable logistic regression and receiver operating characteristic (ROC) analysis. Automated volumetric assessment identified stable (n = 44), increased (n = 109), and decreased (n = 108) stone burden across the evaluated kidneys. Qualitative assessments from radiology reports demonstrated weak diagnostic performance (AUC range, 0.55–0.62), similar to the independent radiologist (AUC range, 0.41–0.72) for differentiating changes in stone burden. A model incorporating higher-order radiomics features achieved an AUC of 0.71 for distinguishing increased versus decreased stone burdens compared with the baseline CT (p < 0.001), but did not outperform threshold-based volumetric assessment. The automated threshold-based volumetric quantification of kidney stone burdens provides higher diagnostic accuracy than qualitative radiologist assessments and radiomics-based analyses for identifying a stable, increased, or decreased stone burden on follow-up CT examinations. Full article

Background and Objective: Information about the type of kidney stones is important for informed therapeutic decisions and the prevention of urolithiasis. Urinary stones are heterogeneous, and their elemental composition and crystal structure vary between patients. The formation of urinary stone deposits depends, among other things, on physiological conditions, the concentration of promoters and inhibitors of crystallization, and proteins found in the urine. The aim of this study was to determine differences in urine osteopontin (OPN) levels between groups of different stone-formers. Methods: Urinary stone specimens (n = 44) were acquired during elective endoscopic procedures. Specimens were divided into subgroups by k-means cluster analysis depending on calcium and phosphorus concentrations. The concentration of urine OPN was determined and compared for each subgroup and the control group. Results: Cluster analysis divided the deposits into three clusters. Cluster 1 contained mainly calcium oxalate deposits; Cluster 2 contained uric acid deposits; Cluster 3 contained deposits with a high content of calcium phosphate. Urine OPN concentration in CaP stone-formers (5.77 ng/mL) differed significantly from those of controls (17.05 ng/mL, p = 0.013) and CaOx stone-formers (15.31 ng/mL, p = 0.048). Conclusions: The concentration of urine OPN varies depending on the elemental composition of renal calculi. The lowest concentration of OPN was determined in the group of patients with a high content of calcium phosphate in the deposits. Full article

Managing nephrolithiasis in chronic kidney disease (CKD) poses a therapeutic challenge: preventing stone recurrence while preserving kidney function. Standard urological interventions and preventive strategies, such as high fluid intake, thiazides, and potassium citrate, cut recurrence by 50–60% in healthy kidneys but risk fluid overload, hyperkalemia, and diminished efficacy in CKD as glomerular filtration rate (GFR) declines. Often, stone prevention and CKD care are addressed separately, leaving clinicians without unified guidance for this rising patient group. This review explores the bidirectional relationship between nephrolithiasis and CKD, integrating pathophysiology and therapeutic strategies into a practical, decision-oriented framework. It offers tailored interventions based on GFR category, stone type, and comorbid conditions, emphasizing the potential for dual-purpose therapies. Going beyond previous reviews, it connects clinical practice with existing research gaps, offering tools to balance outcomes and guide future studies. Full article

Urolithiasis is one of the most burdensome urinary tract conditions with a prevalence ranging from 1% to 20%. Approximately half of the patients experience a recurrence, while 10% face multiple stone episodes. Long before the advent of surgical treatment options, herbal therapy, or phytotherapy, had been used for both the prevention and management of urolithiasis. Recently, interest in phytotherapy has been rekindled due to the limitations associated with modern urolithiasis treatment, the limited options for conventional medical therapy, and the added cost of interventions for stones. While research on phytotherapy is still limited, it is ongoing and is yielding promising results. In order to capture the current trend in phytotherapy for urolithiasis, we performed a narrative review from data collected and synthesized from electronic databases, with a specific focus on randomized human studies. Our analysis revealed that the use of various herbal medicines and phytotherapy, either as mixtures or as sole plant extracts, in urolithiasis is on the rise and is mainly utilized as complementary therapy to conventional treatment. Although most studies demonstrate the effectiveness of phytotherapy in reducing stone size and facilitating stone expulsion, several questions regarding specific dosages, mechanisms of action, drug interactions, treatment duration, and types of stones that respond to phytotherapy remain unanswered. This review aims to summarize the current knowledge surrounding the role of phytotherapy in urolithiasis and to determine its role as a primary or complementary treatment alongside traditional treatment options. Ultimately, further research is essential to clarify the abovementioned unresolved issues, overcome the existing challenges, and optimize the best possible phytotherapy strategies and timing for dissolving specific types of stones with these regimens. Full article

Background/Objectives: Pelvic kidney is a congenital anomaly characterized by the kidney’s failure to ascend to its normal anatomical location during early embryonic development. This anomaly complicates traditional surgical approaches for renal calculi due to the kidney’s atypical positioning and associated anatomical challenges. We sought to summarize our experience with robotic-assisted pyelolithotomy (RPPK) for pelvic kidney stones. Methods: A retrospective review of patients who underwent RPPK was conducted between 2014 and 2023. Demographic data on stone characteristics, operative details, and postoperative outcomes were analyzed. Results: Four patients (three male; mean age—51.2 years with a range of 45–54; mean BMI—26.6 with a range of 22.3–32.2) underwent RPPK. All had a right-sided pelvic kidney; two had prior failed ureteroscopy. The mean stone diameter was 27.7 mm (range: 17–35); the mean density was 1207.5 HU (range: 905–1500). The mean operative time was 265 min (range: 200–323); the time from incision to closure was 142.2 min (range: 95–225). No ureteral stents or drains were used. Blood loss was negligible. The mean hospital stay was 2.2 days. No immediate complications were recorded. The mean follow-up was 11.75 months (range: 3–30). Conclusions: RPPK is safe and effective for managing pelvic kidney stones. Challenging renal anatomy stone size and density are not obstacles to the robotic approach unlike other fragmentation methods Full article

To investigate the role of the intestinal bacterial microbiota in the pathogenesis of calcium oxalate nephrolithiasis in cats, a condition characterized by the formation of kidney stones, it is desirable to identify a sample collection method that accurately reflects the microbiota’s composition. The objective of this study was to evaluate the impact of fecal sample collection methods on the intestinal microbiota composition in two cat populations: healthy cats and kidney stone-diseased cats. The study included eighteen cats from the same colony, comprising nine healthy cats and nine cats with spontaneously occurring presumed calcium oxalate kidney stones. Three fecal collection methods were compared: rectal swabs, the collection of fresh stool, and the collection of stool exposed to ambient air for 24 h. The bacterial microbiota was analyzed through the high-resolution sequencing of the V3–V4 region of the 16S rRNA gene. For all cats, within the same individual, a one-way PERMANOVA analysis showed a significant difference between the rectal swabs and fresh stool (p = 0.0003), as well as between the rectal swabs and stool exposed to ambient air for 24 h (p = 0.0003), but no significant difference was identified between the fresh stool and non-fresh stool (p = 0.0651). When comparing the two populations of cats, this study provides seemingly conflicting results. (1) A principal component analysis (PCA) comparison revealed a significant difference in the bacterial composition between the healthy cats and the cats with kidney stones only when the sample was a fresh fecal sample (p = 0.0037). This finding suggests that the intestinal bacteria involved in the pathogenesis of kidney stones in cats are luminal and strictly anaerobic bacteria. Consequently, exposure to ambient air results in a loss of information, preventing the identification of dysbiosis. For clinical studies, non-fresh stool samples provided by owners does not appear suitable for studying the gut microbiota of cats with kidney stones; fresh stool should be favored. (2) Interestingly, the rectal swabs alone highlighted significant differences in the proportion of major phyla between the two populations. These findings highlight the critical importance of carefully selecting fecal collection methods when studying feline gut microbiota. Combining rectal swabs and fresh stool sampling provides complementary insights, offering the most accurate understanding of the gut microbiota composition in the context of feline kidney stone pathogenesis. Full article

Nephrolithiasis is a medical condition characterized by the existence or development of calculi, commonly referred to as stones within the renal system, and poses significant health challenges. Calcium phosphate and calcium oxalate are the predominant constituents of renal calculi and are introduced into the human body primarily via dietary sources. The presence of oxalates can become particularly problematic when the delicate balance of the normal flora residing within the gastrointestinal tract is disrupted. Within the human gut, species of Oxalobacter, Lactobacillus, and Bifidobacterium coexist in a symbiotic relationship. They play a pivotal role in mitigating the risk of stone formation by modulating certain biochemical pathways and producing specific enzymes that can facilitate the breakdown and degradation of oxalate salts. The probiotic potential exhibited by these bacteria is noteworthy, as it underscores their possible utility in the prevention of nephrolithiasis. Investigating the mechanisms by which these beneficial microorganisms exert their effects could lead to novel therapeutic strategies aimed at reducing the incidence of kidney stones. The implications of utilizing probiotics as a preventive measure against kidney stone formation represent an intriguing frontier in both nephrology and microbiome research, meriting further investigation to unlock their full potential. Full article

Urolithiasis is a medically significant crystallization process affecting the urinary tract. Kidney stones exhibit considerable diversity as they form in complex environments containing various molecules and pathogens. Understanding the formation and occurrence of kidney stones is essential for developing strategies to prevent or reduce the invasiveness of treatments. In this study, we investigated over 300 cases of urolithiasis in Styria, Austria. The composition of the stones was evaluated using infrared spectroscopy and scanning electron microscopy. Most stones were found to be heterogeneous, predominantly composed of calcium oxalate, followed by calcium phosphate. Other components such as struvite, uric acid, and cystine were present to a lesser extent and were more likely to form homogeneous crystals. Analyzing the occurrence of these different stone types provides valuable insights into the formation processes of kidney stones and can aid in the prevention of urolithiasis in the future. Full article

The standard treatment procedures for managing renal calculi in the pediatric population are similar to those in adults. The application of flexible ureteroscopy has contributed to the increased popularity of retrograde intrarenal surgery (RIRS) as an alternative therapeutic modality that can be successfully applied in children. One of the most significant innovations of the last decade is the introduction of single-use flexible ureteroscopes (fURSs). In this case report, we present the case of a 2-year-old boy with multiple large calculi in his right kidney, which were successfully removed after a single session of RIRS using a 7.5 F single-use fURS and high-power laser settings. The total operative and lithotripsy times were estimated at 90 and 75 min, respectively. No complications were recorded. The hemoglobin loss was calculated at 0.3 mg/dL, while the creatinine level was decreased by 0.1 mg/dL. The urethral catheter was removed on the first postoperative day, and the patient was discharged. The management of multiple or large kidney stones is very challenging in the pediatric population under the age of three years. Convenient preoperative planning and the appropriate use of available equipment may lead to excellent outcomes accompanied by a reduced risk for complications. Full article

Abdominal imaging of autosomal dominant polycystic kidney disease (ADPKD) has historically focused on detecting complications such as cyst rupture, cyst infection, obstructing renal calculi, and pyelonephritis; discriminating complex cysts from renal cell carcinoma; and identifying sources of abdominal pain. Many imaging features of ADPKD are incompletely evaluated or not deemed to be clinically significant, and because of this, treatment options are limited. However, total kidney volume (TKV) measurement has become important for assessing the risk of disease progression (i.e., Mayo Imaging Classification) and predicting tolvaptan treatment’s efficacy. Deep learning for segmenting the kidneys has improved these measurements’ speed, accuracy, and reproducibility. Deep learning models can also segment other organs and tissues, extracting additional biomarkers to characterize the extent to which extrarenal manifestations complicate ADPKD. In this concept paper, we demonstrate how deep learning may be applied to measure the TKV and how it can be extended to measure additional features of this disease. Full article

Background: Crystallization experiments of renal-calculi-forming compounds (calcium oxalate, calcium phosphates, uric acid) are normally performed by monitoring these processes during periods of time similar to the residence of urine inside the kidney. Nevertheless, cystine requires high supersaturation for its crystallization, and most experiments last for longer periods. It must be considered that at high supersaturation, the inhibitors of crystalline development have poor effects. Methods: The induction time of crystallization (t_i) of cystine in experimental conditions similar to those of the formation of cystine renal calculi and the effect of different cystine-binding thiol agents was determined through turbidimetric measurements. We also studied the macro- and microstructure of 30 cystine kidney stones through stereoscopic microscopy and scanning electron microscopy. Results: Under the studied conditions, the t_i in absence of crystallization inhibitors was 15 min, and the presence of 9 mM of penicillamine, tiopronin, or N-acetylcysteine totally inhibited crystallization, as their effects relate to the formation of complexes with cystine, although N-acetylcysteine also delayed cystine crystalline development and modified cystine crystal morphology. Cystine stones have traditionally been classified as smooth and rough. The study of their structure shows that all of them begin their formation from a few crystals that generate a compact radial structure. Their subsequent growth, depending on the renal cavity where they are located, gives rise to the rough structure in the form of large blocks of cystine crystals or the smooth structure with small crystals. Conclusions: To prevent the development of cystine renal stones, the formation of small crystals must be avoided by reducing urinary cystine supersaturation, with N-acetylcysteine being the most effective among the studied cystine-binding thiol agents. Also, the removal of cystine crystals through increased water intake and physical activity can be a very important preventive measure. Full article

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. Full article

Background and Objectives: Percutaneous nephrolithotomy (PCNL) is still the gold-standard treatment for large and/or complex renal stones. Endoscopic combined intrarenal surgery (ECIRS) was developed with the goal of minimizing the number of access tracts of PCNL while simultaneously improving the one-step stone-free rate (SFR). The aim of this study was to share the experience of the consecutive 200 cases of ECIRS in one institute and analyze surgical outcomes of mini-ECIRS and standard ECIRS. Materials and Methods: We performed ECIRS for 200 adult patients between July 2017 and January 2020. An ECIRS was performed with the patient under general anesthesia in the intermediate-supine position. Surgeries were finished using a tubeless technique with a simple ureteral stent insertion. Results: There were significant differences in the mean maximal stone length (MSL), the variation coefficient of stone density (VCSD), the linear calculus density (LCD), the Seoul National University Renal Stone Complexity (S-ReSC), and the modified S-ReSC scores in stone characteristics, and estimated blood loss (EBL) and operation time in peri-operative outcomes between conventional and mini-ECIRS. After propensity-score matching, there was only a difference in EBL between the two groups. In logistic regression models, MSL [odds ratio (OR) 0.953; 95% confidence interval (CI) 0.926–0.979; p < 0.001], LCD (OR 4.702; 95% CI 1.613–18.655; p = 0.013) were significant factors for the success rate after ECIRS. Conclusions: In patients who underwent a mini-ECIRS, the stones were relatively smaller and less complex, and the operation time was shorter. However, if the size of stones was similar, there was no difference in the success rate, but EBL was lower in mini-ECIRS than in standard surgery. Full article