Impact of nephrolithiasis on kidney function

The experience of a tertiary referral center with laparoscopic pyelolithotomy for large renal stones during 18 years

This study aimed to evaluate the outcomes of laparoscopic pyelolithotomy, including its efficacy and feasibility in treatment of large renal stones. All patients who underwent laparoscopic pyelolithotomy operations in a referral center were enrolled from 2003 to 2020. The final analysis included 436 patients. The total stone free rate was 88.3% and the stone-free rate for staghorn/multiple stones versus other types of stones was 81% vs. 91% (P = 0.002). Likewise, the total operation duration was 158 ± 50 and the operation duration for staghorn/multiple stones versus other types of stones was 171 ± 51 min vs. 153 ± 49 min (P < 0.001). The operation duration (169 ± 51 vs. 155 ± 58 vs. 155 ± 42 min) and hospitalization (4.5 ± 2.3 vs. 4.0 ± 2.2 vs. 3.6 ± 1.8) decreased with increasing the surgeons' experience over time. The outcomes of laparoscopic pyelolithotomy for children versus adults versus geriatric patients and in patients with normal versus abnormal kidney anatomy did not reveal statistically significant differences. Laparoscopic pyelolithotomy could be employed as an alternative surgical approach for patients with large kidney stones of any age or with kidney abnormalities provided that appropriate expertise is available to carry out the procedure.

A deep learning model for automated kidney calculi detection on non-contrast computed tomography scans in dogs

Nephrolithiasis is one of the most common urinary disorders in dogs. Although a majority of kidney calculi are non-obstructive and are likely to be asymptomatic, they can lead to parenchymal loss and obstruction as they progress. Thus, early diagnosis of kidney calculi is important for patient monitoring and better prognosis. However, detecting kidney calculi and monitoring changes in the sizes of the calculi from computed tomography (CT) images is time-consuming for clinicians. This study, in a first of its kind, aims to develop a deep learning model for automatic kidney calculi detection using pre-contrast CT images of dogs. A total of 34,655 transverseimage slices obtained from 76 dogs with kidney calculi were used to develop the deep learning model. Because of the differences in kidney location and calculi sizes in dogs compared to humans, several processing methods were used. The first stage of the models, based on the Attention U-Net (AttUNet), was designed to detect the kidney for the coarse feature map. Five different models-AttUNet, UTNet, TransUNet, SwinUNet, and RBCANet-were used in the second stage to detect the calculi in the kidneys, and the performance of the models was evaluated. Compared with a previously developed model, all the models developed in this study yielded better dice similarity coefficients (DSCs) for the automatic segmentation of the kidney. To detect kidney calculi, RBCANet and SwinUNet yielded the best DSC, which was 0.74. In conclusion, the deep learning model developed in this study can be useful for the automated detection of kidney calculi.

Asymptomatic hyperuricemia associated with increased risk of nephrolithiasis: a cross-sectional study

BACKGROUND

Existing evidence shows that there is an independent correlation between nephrolithiasis and gout, and hyperuricemia is the most important risk factor for gout. However, hyperuricemia was often used as an accompanying symptom of gout to explore its association with nephrolithiasis, there were few studies to explore whether hyperuricemia itself or serum uric acid (SUA) is related to the risk of nephrolithiasis. Evidence on the relationship between hyperuricemia and nephrolithiasis is still insufficient.

METHODS

A total of 22,303 participants aged 30 to 79 years who participated in the China Multi-Ethnic Cohort (CMEC) study in Yunnan Province from May 2018 to September 2019 were included in the study. All participants received standardized face-to-face interviews, medical examinations, and biochemical examinations. Logistic regression was used to estimate the association between hyperuricemia and nephrolithiasis, and a restricted cubic spline (RCS) model was used to explore the dose-response relationship between SUA and the risk of nephrolithiasis.

RESULTS

14.5% of all participants were diagnosed with hyperuricemia, and 12.1% were diagnosed with nephrolithiasis. After adjusting for all potential confounders, the OR (95%CI) for nephrolithiasis in participants with hyperuricemia compared with participants without hyperuricemia was 1.464 (1.312,1.633), p < 0.001. Restricted cubic spline regression analysis showed that the risk of nephrolithiasis increased with the increase of SUA, and when the level of SUA is higher than 356 μmol/L in males and higher than 265 μmol/L in females, there is a dose-response relationship between the increase of SUA and the risk of nephrolithiasis in both males and females (p for nonlinearity = 0.1668, p for nonlinearity = 0.0667).

CONCLUSION

Asymptomatic hyperuricemia is associated with an increased risk of developing nephrolithiasis. Before reaching the diagnostic criteria for hyperuricemia, the risk of nephrolithiasis rises with the increase in SUA. This suggests that controlling SUA levels may be significant for the prevention of nephrolithiasis.

Oxalate Homeostasis in Non-Stone-Forming Chronic Kidney Disease: A Review of Key Findings and Perspectives

Chronic kidney disease (CKD) is a significant global public health concern associated with high morbidity and mortality rates. The maintenance of oxalate homeostasis plays a critical role in preserving kidney health, particularly in the context of CKD. Although the relationship between oxalate and kidney stone formation has been extensively investigated, our understanding of oxalate homeostasis in non-stone-forming CKD remains limited. This review aims to present an updated analysis of the existing literature, focusing on the intricate mechanisms involved in oxalate homeostasis in patients with CKD. Furthermore, it explores the key factors that influence oxalate accumulation and discusses the potential role of oxalate in CKD progression and prognosis. The review also emphasizes the significance of the gut-kidney axis in CKD oxalate homeostasis and provides an overview of current therapeutic strategies, as well as potential future approaches. By consolidating important findings and perspectives, this review offers a comprehensive understanding of the present knowledge in this field and identifies promising avenues for further research.

SPP1 and UMOD gene variants are synergistically associated with risk of renal stone disease

OBJECTIVE

Calcium and oxalate are the most abundant metabolites present in the stone matrix. The SPP1 and UMOD gene has specific expression in kidneys and are involved in various stages of stone formation. Therefore, genetic variants in the SPP1 and UMOD genes may enhance the development of renal stone disease. This study has been designed to understand the association of genetic variants of SPP1 and UMOD genes with renal stone disease.

MATERIALS AND METHOD

A prospective study has been carried out, including 150 renal stone disease patients and 150 healthy individuals. Biochemical parameters were performed, including serum calcium levels, creatinine, parathyroid hormone, and 24-Hour urine metabolites. The genotyping of SPP1 (rs1126616) and UMOD (rs4293393) gene variants were performed using a customized TaqMan probe. T-test was used for continuous biochemical data analysis. The Chi-square test has been applied to assess the risk of a particular genotype associated with renal stone disease. In addition, correlation analysis for biochemical parameters and genetic variants with the renal stone disease has been performed using Shapley additive explanations (SHAP) values calculated with the help of the pycaret library.

RESULT

Renal stone patients had significantly higher levels of parathyroid hormone (93.37 ± 52.78 pg/ml vs 64.67 ± 31.50 pg/ml, P=<0.0001), serum creatinine (0.94 ± 0.38 mg/dl vs 0.77 ± 0.17 mg/dl, P=<0.0001) and 24hr urine metabolites in comparison to the healthy controls. Heterozygous (CT) variant of SPP1 and homozygous (GG) variant of UMOD genes were significantly associated with an increased risk of developing the renal stone disease (p = 0.0100, OR = 2.06, 95 %CI = 1.13-3.75; p=<0.0001, OR = 5.773, 95 % CI = 2.03-16.38, respectively). Individuals with hyperparathyroidism and CC (SPP1) and GG (UMOD) genotypes have a high risk (P = 0.0055, OR = 2.75, 95 %CI = 1.35-5.67; P = 0.0129, OR = 10.03, 95 %CI = 1.60-110.40, respectively) of developing a renal stone. In addition, individuals with hypercalciuria and TT genotype of SPP1 (P = 0.0112, OR = 2.92, 95 % CI = 1.33-6.35), AG genotype of UMOD (P=<0.0001, OR = 5.45, 95 %CI = 2.24-13.96) and GG genotype of UMOD (P=<0.0001, OR = 10.02, 95 %CI = 3.53-24.63) have high risk of developing renal stones. Moreover, Individuals with hyperoxaluria and AG + GG (UMOD) genotype have a greater risk (P=<0.0001, OR = 7.35, 95 % CI = 3.83-13.68) of developing a renal stone. The renal stone risk was persistent (P=<0.0002, OR = 2.44, 95 % CI = 1.52-3.86) when analyzed for the synergistic effect of risk genotypes of SPP1 (CT) and UMOD (GG) gene. Further, correlation analysis also confirmed the strong association between genetic variants and renal stone development.

CONCLUSION

Genetic variants of the SPP1 and UMOD genes were associated with renal stone disease. In the presence of risk genotype and hyperparathyroidism, hypercalciuria, and hyperoxaluria, the susceptibility to develop the renal stone disease risk gets modulated.

Physical activity can influence the relationship between ethylene oxide and risk of kidney stones: A cross-sectional study from the NHANES 2013-2016

Ethylene oxide (EO) is known to cause inflammatory damage, and suitable physical activity can reportedly affect the risk of kidney stones. In this study, we aimed to investigate the relationship between EO and kidney stones and whether physical activity can potentially influence the relationship between EO and kidney stones. Overall, 3,336 adult participants were included; of them, 330 (9.9%) had a self-reported history of kidney stones. Data were obtained from the National Health and Nutrition Examination Survey 2013-2016. Physical activity was calculated using metabolic equivalent, weekly frequency, and duration. Logistic regression and restricted cubic spline (RCS) curves were used to explore the association between physical activity, EO, and kidney stones. Dose-response curves from the RCS showed a nonlinear positive association between EO and kidney stones. Multivariate logistic regression analysis revealed an adjusted odds ratio (aOR) of 1.548 (95% confidence interval 1.123-2.135, P = 0.008) for the risk of kidney stones among participants in the highest quartile (Q4) group compared with those in the lowest quartile (Q1) group. Furthermore, compared to the Q1 group, the aOR for risk of kidney stones in the Q4 group was 1.326 in participants without physical activity, a decreased risk (aOR 1.239) in participants with low physical activity, and an increased risk (aOR 1.981) in those with high physical activity. This study suggests that EO is a risk factor for kidney stones and that suitable physical activity may moderate this relationship to some extent; however, excessive physical activity can exacerbate this relationship.

Recurrent nephrolithiasis and loss of kidney function: a cohort study

PURPOSE

To evaluate whether symptomatic recurrent nephrolithiasis leads to loss of kidney function.

METHODS

Adults who presented to the Emergency Department at least twice with symptomatic and radiologically confirmed nephrolithiasis were retrospectively recruited. Primary endpoint was the change in glomerular filtration rate (GFR) between baseline and at the time of data collection. Secondary endpoints include GFR slope defined as the mean rate of change in GFR from baseline to the end of the study period.

RESULTS

240 patients had recurrent symptomatic nephrolithiasis. Median follow-up was 5.4 years. The median age of first acute presentation was 51.6 years and the median baseline serum creatinine (bsCr) was 85.5 umol/l. 17.5% (n = 42) had worsening GFR, with the average change in GFR of - 8.64 ml/min/1.73 m² per year. Four patients progressed to ESKD requiring haemodialysis. 14.5% (n = 35) had calcium oxalate stones. Univariate analysis showed older patients (p < 0.001), more symptomatic stone episodes (p < 0.001) and non-calcium-containing stones (p < 0.001) were strongly associated with deteriorating kidney function. Age (p = 0.002) and number of acute stone episodes (p = 0.011) were significant predictive factors when unadjusted to co-morbidities. Age (p = 0.018) was the only predictive factor of worsening GFR when adjusted for co-morbidities. Average mean GFR slope was - 2.83/min/1.73 m² per year.

CONCLUSIONS

Recurrent symptomatic nephrolithiasis is associated with loss of kidney function, in older patients, increased episodes of symptomatic nephrolithiasis and non-calcium-containing stones. Age is the only predictive factor for progression to chronic kidney disease in this subgroup.

Haplotype of CaSR gene is associated with risk of renal stone disease in West Indian population

Calcium is the most abundant metabolite involved in the stone matrix. The CaSR gene controls calcium homeostasis, and genetic variation in the CaSR gene could lead to the development of renal stone disease. Therefore, the current study has been designed to assess the association of genetic variants of CaSR gene polymorphisms with renal stone disease. A single-centric prospective study has been carried out on a total of 300 participants (150 cases and 150 controls). Serum levels of calcium, creatinine, parathyroid hormone, and 24 h urine metabolites were measured. Two polymorphisms, rs1801725 and rs1042636, of the CaSR gene, have been genotyped for each participant. T test, binary logistic regression, and Chi-square analysis were used for statistical analysis. Renal stone patients had significantly higher levels of serum parathyroid hormone, creatinine, and 24-h urine metabolites in comparison to the controls. CaSR gene variants, rs1801725 (GG) and rs1042636 (AA), both have shown significant association with renal stone disease. In addition, individuals having specific genotypes along with metabolic abnormalities such as hypercalcemia and hyperparathyroidism are found to be at a higher significant risk of developing the renal stone disease. In the present study, the haplotype of the CaSR gene has shown an association with renal stone disease. Individuals with hyperparathyroidism and hypercalcemia and risk genotype have a higher susceptibility to developing renal stone disease.

Prevalence and risk factors of kidney stone disease in population aged 40-70 years old in Kharameh cohort study: a cross-sectional population-based study in southern Iran

BACKGROUND

Kidney stone is the major cause of morbidity, and its prevalence is increasing in the world. This study aimed to assess the prevalence and risk factors of kidney stone in the adult population of southern Iran based on the data of the Kharameh Cohort Study.

METHODS

This cross-sectional study was conducted on 10,663 individuals aged 40-70 years old, using the baseline data of Kharamah cohort study, which started in 2014. Among all participants, 2251 individuals had a history of kidney stone. The participants' demographic characteristics, behavioral habits, and the history of underlying diseases were investigated. The crude and Age Standardized Prevalence Rate of kidney stones was calculated. Also, logistic regression was used to identify the predictors of kidney stone. To check the goodness of fit index of the model, we used the Hosmer-Lemeshow test. All analyses were performed in STATA software.

RESULTS

The prevalence of kidney stone was estimated 21.11%. Also, the Age Standardized Prevalence Rate in men and women was calculated 24.3% and 18.7%, respectively. The mean age of the participants was 52.15 years. Higher prevalence of kidney stone was seen in women aged 40-50 years (40.47%, p = 0.0001) and moderate level of social economic status (31.47%, p = 0.03), men with overweight (44.69%, p < 0.0001) and those in a very high level of social economic status (35.75%, p = 0.001). The results of multiple logistic regression showed that the chance of having kidney stone was 1.17 times higher in diabetic individuals, 1.43 times higher in hypertensive individuals, 2.21 times higher in individuals with fatty liver, and 1.35 times higher in individuals with overweight. The level of socio economic status, male sex, and age were the other factors related to kidney stone.

CONCLUSION

In this study, underlying diseases such as fatty liver, diabetes, and hypertension as well as age, male sex, overweight, and high social economic status were identified as important risk factors for kidney stone. Therefore, identifying individuals at risk of kidney stone and providing the necessary training can greatly help to reduce this disease. However, health policymakers should prepare preventive strategies to reduce the occurrence of kidney stone.

Epidemiology of Urolithiasis with Sex and Working Status Stratification Based on the National Representative Cohort in Republic of Korea

Background

This study aimed to estimate the annual prevalence and incidence of urolithiasis stratified by work status based on a large nationwide sample.

Methods

This study used data from the National Health Insurance Service-National Sample Cohort from 2002 to 2015. The prevalence and incidence of urolithiasis were estimated based on work status and gender stratification. The risk of urolithiasis among workers was calculated using age-standardized incidence ratio with stratification of work type.

Results

The prevalence of urolithiasis was significantly higher in workers than in non-workers, especially men, during the follow-up period. The total estimated number of urolithiasis cases was 41,086 and the overall incidence of urolithiasis was 0.3%. The age-standardized incidence ratio of urolithiasis was significantly higher among the total workers (1.14; 95% confidence interval, 1.13-1.16), self-employed workers (1.08; 95% confidence interval, 1.06-1.11), and paid workers (1.19; 95% confidence interval, 1.17-1.21) than among the non-working population.

Conclusions

Workers, especially paid workers and men, were vulnerable to urolithiasis. Further studies are required to investigate the effects of working conditions on urolithiasis.

Advances in Assistive Electronic Device Solutions for Urology

Recent technology advances have led urology to become one of the leading specialities to utilise novel electronic systems to manage urological ailments. Contemporary bladder management strategies such as urinary catheters can provide a solution but leave the user mentally and physically debilitated. The unique properties of modern electronic devices, i.e., flexibility, stretchability, and biocompatibility, have allowed a plethora of new technologies to emerge. Many novel electronic device solutions in urology have been developed for treating impaired bladder disorders. These disorders include overactive bladder (OAB), underactive bladder (UAB) and other-urinary-affecting disorders (OUAD). This paper reviews common causes and conservative treatment strategies for OAB, UAB and OUAD, discussing the challenges and drawbacks of such treatments. Subsequently, this paper gives insight into clinically approved and research-based electronic advances in urology. Advances in this area cover bladder-stimulation and -monitoring devices, robot-assistive surgery, and bladder and sphincter prosthesis. This study aims to introduce the latest advances in electronic solutions for urology, comparing their advantages and disadvantages, and concluding with open problems for future urological device solutions.

Is This Your Stone? Distinguishing Phleboliths and Nephroliths on Imaging in the Emergency Department Setting

BACKGROUND

Ureteral stones are a common diagnosis in the emergency department (ED) setting, often found with computed tomography (CT). The high frequency of phleboliths can confound ureteral stone diagnosis on CT imaging.

OBJECTIVE

This article provides a narrative review of the etiological, epidemiological, and radiological distinctions between ureteral stones and phleboliths for appropriate ED diagnosis and management.

DISCUSSION

Multiple studies demonstrate phleboliths, benign calcified thrombi largely in pelvic vasculature, are found at frequencies equal to or greater than those of ureteral stones on CT imaging. The calcified foundation of phleboliths and most ureteral stones, as well as the close proximity of the distal ureters to pelvic vasculature, can cause consternation in the proper diagnosis of ureteral stones in the patient with abdominal pain. Radiological findings of circumferential ureteral soft tissue edema ("rim sign") and an irregular tapering soft tissue mass ("comet tail sign") can suggest a ureteral and phlebolith etiology, respectively. These signs demonstrate high specificity but low sensitivity, and clinicians must use history, examination, and secondary signs on imaging to differentiate ureteral stones from phleboliths.

CONCLUSIONS

Phleboliths are a common finding on CT imaging. Radiological findings of rim sign and comet tail sign may help to differentiate phleboliths and ureteral stones; however, their low sensitivity and inconsistent presentation should prompt greater reliance on other signs of ureteral obstruction to aid in diagnosis of undifferentiated pelvic calcifications.

Association between body fat distribution and kidney stones: Evidence from a US population

OBJECTIVES

We aimed to evaluate the relationship between the proportion of Android to Gynoid ratio and the incidence of kidney stones among US adults.

METHODS

Participants aged 20-59 years from the 2011-2018 National Health and Nutrition Examination Survey (NHANES) database were selected to assess the association between Android to Gynoid ratio and kidney stone prevalence using logistic regression analysis, subgroup analysis and calculation of dose-response curves.

RESULTS

This study ultimately included 10858 participants, of whom 859 self-reported a history of kidney stones. And after adjusting for all confounders, an increased Android to Gynoid ratio was associated with an increased prevalence of kidney stones (OR=2.75, 95% CI:1.62-4.88). And subgroup analysis showed an increased prevalence of kidney stones in women (OR=3.55, 95% CI: 1.54-8.22), non-diabetic (OR=2.59, 95% CI: 1.45-4.60), 60 > age ≥ 40 years (OR=3.51, 95% CI: 1.83-6.71), Mexican-American (OR=4.35, 95% CI: 1.40- 13.53) and white (OR=3.86, 95% CI: 1.82-8.18) groups, there was a significant positive association between A/G ratio and kidney stones. In contrast, in the hypertensive subgroup, the A/G ratio was associated with kidney stones in all groups.

CONCLUSIONS

Higher Android to Gynoid ratio is associated with a high prevalence of kidney stone disease.

Application of Radiomics Model of CT Images in the Identification of Ureteral Calculus and Phlebolith

OBJECTIVE

To investigate the clinical application of the three-dimensional (3D) radiomics model of the CT image in the diagnosis and identification of ureteral calculus and phlebolith.

METHOD

Sixty-one cases of ureteral calculus and 61 cases of phlebolith were retrospectively investigated. The enrolled patients were randomly categorized into the training set (n = 86) and the testing set (n = 36) with a ratio of 7 : 3. The plain CT scan images of all samples were manually segmented by the ITK-SNAP software, followed by radiomics analysis through the Analysis Kit software. A total of 1316 texture features were extracted. Then, the maximum correlation minimum redundancy criterion and the least absolute shrinkage and selection operator algorithm were used for texture feature selection. The feature subset with the most predictability was selected to establish the 3D radiomics model. The performance of the model was evaluated by the receiver operating characteristic (ROC) curve, and the area under the ROC curve (AUC) was also calculated. Additionally, the decision curve was used to evaluate the clinical application of the model.

RESULTS

The 10 selected radiomics features were significantly related to the identification and diagnosis of ureteral calculus and phlebolith. The radiomics model showed good identification efficiency for ureteral calculus and phlebolith in the training set (AUC = 0.98; 95%CI: 0.96-1.00) and testing set (AUC = 0.98; 95%CI: 0.95-1.00). The decision curve thus demonstrated the clinical application of the radiomics model.

CONCLUSIONS

The 3D radiomics model based on plain CT scan images indicated good performance in the identification and prediction of ureteral calculus and phlebolith and was expected to provide an effective detection method for clinical diagnosis.

Oxalate Alters Cellular Bioenergetics, Redox Homeostasis, Antibacterial Response, and Immune Response in Macrophages

Individuals with calcium oxalate (CaOx) kidney stones can have secondarily infected calculi which may play a role in the development of recurrent urinary tract infection (UTI). Uropathogenic Escherichia coli (UPEC) is the most common causative pathogen of UTIs. Macrophages play a critical role in host immune defense against bacterial infections. Our previous study demonstrated that oxalate, an important component of the most common type of kidney stone, impairs monocyte cellular bioenergetics and redox homeostasis. The objective of this study was to investigate whether oxalate compromises macrophage metabolism, redox status, anti-bacterial response, and immune response. Monocytes (THP-1, a human monocytic cell line) were exposed to sodium oxalate (soluble oxalate; 50 µM) for 48 hours prior to being differentiated into macrophages. Macrophages were subsequently exposed to calcium oxalate crystals (50 µM) for 48 hours followed by UPEC (MOI 1:2 or 1:5) for 2 hours. Peritoneal macrophages and bone marrow-derived macrophages (BMDM) from C57BL/6 mice were also exposed to oxalate. THP-1 macrophages treated with oxalate had decreased cellular bioenergetics, mitochondrial complex I and IV activity, and ATP levels compared to control cells. In addition, these cells had a significant increase in mitochondrial and total reactive oxygen species levels, mitochondrial gene expression, and pro-inflammatory cytokine (i.e. Interleukin-1β, IL-1β and Interleukin-6, IL-6) mRNA levels and secretion. In contrast, oxalate significantly decreased the mRNA levels and secretion of the anti-inflammatory cytokine, Interleukin-10 (IL-10). Further, oxalate increased the bacterial burden of primary macrophages. Our findings demonstrate that oxalate compromises macrophage metabolism, redox homeostasis, and cytokine signaling leading to a reduction in anti-bacterial response and increased infection. These data highlight a novel role of oxalate on macrophage function.

THE FUNCTIONAL STATE OF THE RENAL PARENCHYMA AFTER VARIOUS VIDEO ENDOSURGICAL METHODS OF TREATMENT OF PATIENTS WITH LARGE AND COMPLEX KIDNEY STONES

The work is based on the analysis of literature data devoted to the problem of preserving the functional state of the kidneys with various video endoscopic methods of surgical treatment of large and complex kidney stones. The purpose of the review is to highlight the likelihood of deterioration in the functional state of the kidneys in the postoperative period. A detailed analysis of postoperative outcomes in various minimally invasive methods of treatment of patients with large and complex kidney stones was carried out, with an overview of the possibility of using dynamic nephroscintigraphy as a method of objectively assessing the functional state of the kidneys.

Computer-aided diagnosis system for the classification of multi-class kidney abnormalities in the noisy ultrasound images

BACKGROUND AND OBJECTIVE

The primary causes of kidney failure are chronic and polycystic kidney diseases. Cyst, stone, and tumor development lead to chronic kidney diseases that commonly impair kidney functions. The kidney diseases are asymptomatic and do not show any significant symptoms at its initial stage. Therefore, diagnosing the kidney diseases at their earlier stage is required to prevent the loss of kidney function and kidney failure.

METHODS

This paper proposes a computer-aided diagnosis (CAD) system for detecting multi-class kidney abnormalities from ultrasound images. The presented CAD system uses a pre-trained ResNet-101 model for extracting the features and support vector machine (SVM) classifier for the classification purpose. Ultrasound images usually gets affected by speckle noise that degrades the image quality and performance of the CAD system. Hence, it is necessary to remove speckle noise from the ultrasound images. Therefore, a CAD based system is proposed with the despeckling module using a deep residual learning network (RLN) to reduce speckle noise. Pre-processing of ultrasound images using deep RLN helps to drastically improve the classification performance of the CAD system. The proposed CAD system achieved better prediction results when compared to the existing state-of-the-art methods.

RESULTS

To validate the proposed CAD system performance, the experiments have been carried out in the noisy kidney ultrasound images. The designed system framework achieved the maximum classification accuracy when compared to the existing approaches. The SVM classifier is selected for the CAD system based on performance comparison with various classifiers like K-nearest neighbour, tree, discriminant, Naive Bayes, and linear.

CONCLUSIONS

The proposed CAD system outperforms in classifying the noisy kidney ultrasound images precisely as compared to the existing state-of-the-art methods. Further, the CAD system is evaluated in terms of selectivity and sensitivity scores. The presented CAD system with the pre-processing module would serve as a real-time supporting tool for diagnosing multi-class kidney abnormalities from the ultrasound images.

Amelioration of lithiatic injury to renal tissue by candesartan and sodium thiosulfate in a rat model of nephrolithiasis

AIM

Nephrolithiasis is a chronic metabolic condition affecting 10% of population worldwide. The present study aimed to investigate the possible protective role of candesartan (CAND) and sodium thiosulfate (STS) in ameliorating ethylene glycol (EG) induced nephrolithiasis.

METHODS

One hundred male Wistar rats were divided into five groups: Normal control group, nephrolithiasis (EG) group (1% EG in drinking water), Cystone (CYS) group (EG + 750 mg/kg CYS, orally, once daily), STS group (EG + 0.4 gm/kg STS, intraperitoneally, 3 times/week) and CAND group (EG + 70 μg/mL CAND in drinking water). Treatments and EG administration commenced on the same day and continued for 28 days. CYS was used as reference drug. Urine, blood, and renal tissues were collected at the end of the experiment for assessment of kidney function tests (serum creatinine and urea), urinary (8-hydroxydeoxyguanosine (8-OHdG), calcium and oxalate), inflammatory and oxdative stress biomarkers (transforming growth factor beta (TGF-β), osteopontin (OPN) and ratio of reduced glutathione to oxidized glutathione (GSH/GSSG)) in renal tissue.

RESULTS

Serum (creatinine and urea), urinary (8-OHdG and oxalate) and renal (OPN and TGF-β) were significantly reduced in CAND and STS groups compared to EG group. Furthermore, renal GSH/GSSG and urinary calcium were significantly increased in CAND and STS groups compared to EG group. Histopathological results support the biochemical findings; CAND and STS groups showed less retention of crystals and necrotic damage in kidney. Also, microscopic examination of urine revealed less crystal for CAND and STS groups.

CONCLUSION

Candesartan and sodium thiosulfate exhibited protective effect against nephrolithiasis.

An ensemble of deep neural networks for kidney ultrasound image classification

BACKGROUND AND OBJECTIVE

Chronic kidney disease is a worldwide health issue which includes not only kidney failure but also complications of reduced kidney functionality. Cyst formation, nephrolithiasis or kidney stone, and renal cell carcinoma or kidney tumor are the common kidney disorders which affects the functionality of kidneys. These disorders are typically asymptomatic, therefore early and automatic diagnosis of kidney disorders are required to avoid serious complications.

METHODS

This paper proposes an automatic classification of B-mode kidney ultrasound images based on the ensemble of deep neural networks (DNNs) using transfer learning. The ultrasound images are usually affected by speckle noise and quality selection in the ultrasound image is based on perception-based image quality evaluator score. Three variant datasets are given to the pre-trained DNN models for feature extraction followed by support vector machine for classification. The ensembling of different pre-trained DNNs like ResNet-101, ShuffleNet, and MobileNet-v2 are combined and final predictions are done by using the majority voting technique. By combining the predictions from multiple DNNs the ensemble model shows better classification performance than the individual models. The presented method proved its superiority when compared to the conventional and DNN based classification methods. The developed ensemble model classifies the kidney ultrasound images into four classes, namely, normal, cyst, stone, and tumor.

RESULTS

To highlight effectiveness of the proposed approach, the ensemble based approach is compared with the existing state-of-the-art methods and tested in the variants of ultrasound images like in quality and noisy conditions. The presented method resulted in maximum classification accuracy of 96.54% in testing with quality images and 95.58% in testing with noisy images. The performance of the presented approach is evaluated based on accuracy, sensitivity, and selectivity.

CONCLUSIONS

From the experimental analysis, it is clear that the ensemble of DNNs classifies the majority of images correctly and results in maximum classification accuracy as compared to the existing methods. This automatic classification approach is a supporting tool for the radiologists and nephrologists for precise diagnosis of kidney diseases.

Effect of Phaseolus Vulgaris on Urinary Biochemical Parameters among Patients with Kidney Stones in Saudi Arabia

The study purpose was to investigate the effect of Phaseolus Vulgaris (PV) on urinary biochemical parameters among patients with kidney stones. We conducted a randomized controlled study among 60 patients with kidney stones (size < 10 mm) in the nephrology unit of both government and private hospitals, Al-Ahsa. Urinary volume, calcium, magnesium, potassium, oxalate, uric acid, and power of hydrogen (pH) were assessed before and after the intervention of giving 250 g of PV consumption as an extract thrice weekly (2.2 L to 2.5 L per week) for 6 weeks, which was compared with control. A 't' test was used with the significance at 5%. Mean score of age was 44.5 ± 10.16 in PV group and 43.73 ± 9.79 in control. Four (13.3%) and two (6.7%) had family history of kidney stones. Body mass Index (BMI) mean was 26.44 ± 2.7 and 26.36 ± 2.65 in pre and post-test, respectively, which were significant (p = 0.01017). There were significant changes (p = 0.000) in urine volume from 1962 ± 152.8 to 2005 ± 148.8, calcium 205.4 ± 11.99 to 198.4 ± 12.52, potassium 44.07 ± 3.66 to 52.15 ± 4.37, oxalate 37.12 ± 5.38 to 33.02 ± 5.71, and uric acid 6.88 ± 0.7 to 6.31 ± 0.58. In conclusion, PV is effective management for the patients with kidney stones as it increases the urinary volume and enhances the elimination of small kidney stones.

Endoscopic nephrolithotomy for the removal of complicated nephroliths in dogs and cats: 16 kidneys in 12 patients (2005-2017)

OBJECTIVE

To describe techniques and outcomes for dogs and cats undergoing endoscopic nephrolithotomy (ENL) for the removal of complicated nephroliths.

ANIMALS

11 dogs and 1 cat (n = 16 renal units) with complicated nephroliths that underwent ENL via a surgically assisted ENL approach (12 renal units) or a percutaneous nephrolithotomy approach (4 renal units) between December 2005 and June 2017.

PROCEDURES

Data were obtained from the medical records regarding preoperative, operative, and postoperative findings. Follow-up information on complications and outcomes was also collected.

RESULTS

Indications for nephrolith removal included massive calculi displacing parenchyma (n = 7), recurrent urinary tract infections (5), and ureteral outflow obstruction (4). Median nephrolith diameter was 2.5 cm (range, 0.5 to 5.7 cm). Nephrolith composition differed among patients; calcium oxalate was the most common type (n = 7 [including 2 mixed nephroliths containing ≥ 60% calcium oxalate]). Following ENL (median duration, 180 minutes), 15 of 16 renal units were completely nephrolith free. Procedure-related complications included renal puncture-associated hemorrhage requiring a blood transfusion (n = 1), renal capsule tear (1), and ureteral puncture (1); all were managed without adverse consequence. Five of 12 patients remained alive at the final follow-up (median, 557 days after ENL), and none died from the procedure.

CONCLUSIONS AND CLINICAL RELEVANCE

ENL as performed was safe and effective in removing complicated nephroliths in a renal-sparing manner for the patients in this study. This procedure requires technical training and could be considered for the treatment of complicated nephrolithiasis in dogs and possibly cats.

Association of sirtuin 1 gene polymorphisms with nephrolithiasis in Eastern chinese population

Sirtuin 1 (SIRT1), an NAD⁺-dependent deacylase, has been identified to be associated with renal tubular inflammatory conditions and metabolic disorders, which are risk factors of nephrolithiasis. To further confirm the role of the SIRT1 in kidney stone formation, the expression of SIRT1 was analyzed based on a mouse model and the genetic polymorphisms of SIRT1 gene was compared between patients with kidney stones and controls. The calcium oxalate (CaOx) crystal-induced renal injury model was established to analyzed the expression of SIRT1 in the kidney tissue of both wild-type and ApoE(−/−) mice. And a total of 430 Eastern Chinese subjects (215 patients with nephrolithiasis and 215 age- and gender-matched controls) were recruited for the present study to investigate the associations between 6 common single nucleotide polymorphisms (SNPs) (i.e., rs10509291, rs3740051, rs932658, rs33957861, rs3818292 and rs1467568) in the SIRT1 gene and the incidence of kidney stones. Pairwise linkage disequilibrium and the haplotypes of the 6 SNPs were also analyzed. The genotypes of SIRT1 gene polymorphisms were analyzed by a Snapshot assay. Reduced expression of SIRT1 was observed in the kidney of the mice in the crystal group, revealing the potential role of SIRT1 in the nephrolithiasis. However, we did not find a significant association between the 6 SNPs of the SIRT1 gene and kidney stone formation in the Eastern Chinese population.

A Retrospective Study of Kidney Stone Recurrence in Adults

Background

Nephrolithiasis or kidney stone disease (KSD) is a common disorder worldwide. Despite the availability of a variety of effective management strategies, KSD recurrence remains a problem. In the present study, we investigated the KSD recurrence after the treatment of the first stone episode.

Methods

Medical records of all patients who had KDS treated in our department from January 2012 to January 2016 were retrospectively reviewed. A total of 146 patients who had KDS recurrence were identified. The demographic information, biochemical data, treatment methods, report of hydronephrosis severity and stone chemical compositions were collected and analyzed.

Results

We reported that: 1) Sixty four (43.8%) out of 146 patients with stone recurrence were overweight or obese; 2) Of all 146 patients with stone recurrence, 86 (58.9%) had hyperlipidemia, 77 (52.4%) had hyperuricemia and 64 (43.8%) had hyperglycemia; 3) Mini-invasive methods were mostly used for the treatment of the first stone episode; 4) The most chief complaint differed during the first episode and recurrence; 5) The number of patients who had grades 3 and 4 hydronephrosis was significantly lower during recurrence compared with that in the first stone episode; 6) Seventy nine (54.1%) patients with recurrence had stone of calcium oxalate.

Conclusions

Majority of patients with KSD recurrence have overweight/obesity, hyperlipidemia, hyperuricemia and hyperglycemia, indicating a role of metabolic disorders in stone recurrence. Mini-invasive methods are the mainstay for the management of the first stone episode. The degree of hydronephrosis is significantly reduced during stone recurrence, possibly due to increased awareness of the disease and thereafter the change of lifestyle in patients. Over half of recurrent stones are of calcium oxalate.

Baseline chronic kidney disease does not predict long-term renal functional decline after percutaneous nephrolithotomy

To compare renal functional outcomes in patients with and without chronic kidney disease (CKD) to identify predictors of change in renal function after percutaneous nephrolithotomy (PCNL). We reviewed patients who underwent PCNL by a single surgeon over 3.5 years. Patients' pre- and post-operative Glomerular Filtration Rate (GFR) was calculated. Baseline GFR < 60 ml/min/1.73 m² (stage ≥ 3 CKD) defined our CKD cohort. Patients' baseline renal function, comorbidities, stone parameters, and intra-operative variables were analyzed to determine the relationship with post-operative renal function after PCNL by multivariate analysis. 202 patients were analyzed. Mean follow-up time was 16 months. At baseline, 163 (80.7%) patients were free of CKD and 39 (19.3%) had CKD. Patients without CKD had an overall decrease in GFR from 105.6 to 103.3 ml/min/1.73 m² (p = 0.494). 14/163 (8.6%) non-CKD patients experienced a significant decline in renal function after PCNL; 7/163 (4.3%) developed de novo CKD and 7 had a ≥ 30% decline in GFR. Patients with CKD had an overall increase in mean GFR post-operatively, from 47.3 to 54.0 ml/min/m² (p = 0.067). Two in this cohort (5.1%) experienced a > 30% decline in renal function post-operatively. Age, gender, African American race, presence of comorbidities and pre-operative CKD were not significant predictors of renal function post-operatively on multivariate analysis. PCNL in this cohort appears GFR neutral in the setting of baseline CKD. CKD was not predictive of renal functional decline after PCNL. Given that stone disease carries a high recurrence rate and that CKD is associated with stone formers, further investigation into predictors of renal function change after PCNL is warranted.

Nephrolithiasis: A complication of pediatric diabetic ketoacidosis

OBJECTIVE

To determine the frequency of nephrolithiasis as a complication of diabetic ketoacidosis (DKA) in pediatrics.

METHODS

We performed a retrospective chart review of patients with DKA admitted to a pediatric hospital between January 2009 and July 2016. We identified patients with nephrolithiasis during admission for DKA.

RESULTS

We identified 395 episodes of DKA over 7.5 years. Nephrolithiasis developed as a complication of DKA in 3 of those admissions (0.8%). All three patients with nephrolithiasis were males with new onset type 1 diabetes, aged 11 to 16.5 years. They all developed symptoms of nephrolithiasis after transition to subcutaneous insulin. One patient had subsequent worsening acidosis that required an additional 24 hours of IV insulin administration.

CONCLUSIONS

Nephrolithiasis is a rare complication of pediatric DKA, and should be considered in children with DKA who develop hematuria, flank pain, or suprapubic pain. Nephrolithiasis can increase insulin resistance due to increased pain and inflammation, so these patients should be monitored closely for recurrence of DKA. As patients with diabetes have increased risk of chronic kidney disease and nephrolithiasis can cause kidney injury, risk factors for nephrolithiasis should be identified and addressed to avoid subsequent kidney damage.

Kidney Stone Disease: An Update on Current Concepts

Kidney stone disease is a crystal concretion formed usually within the kidneys. It is an increasing urological disorder of human health, affecting about 12% of the world population. It has been associated with an increased risk of end-stage renal failure. The etiology of kidney stone is multifactorial. The most common type of kidney stone is calcium oxalate formed at Randall's plaque on the renal papillary surfaces. The mechanism of stone formation is a complex process which results from several physicochemical events including supersaturation, nucleation, growth, aggregation, and retention of urinary stone constituents within tubular cells. These steps are modulated by an imbalance between factors that promote or inhibit urinary crystallization. It is also noted that cellular injury promotes retention of particles on renal papillary surfaces. The exposure of renal epithelial cells to oxalate causes a signaling cascade which leads to apoptosis by p38 mitogen-activated protein kinase pathways. Currently, there is no satisfactory drug to cure and/or prevent kidney stone recurrences. Thus, further understanding of the pathophysiology of kidney stone formation is a research area to manage urolithiasis using new drugs. Therefore, this review has intended to provide a compiled up-to-date information on kidney stone etiology, pathogenesis, and prevention approaches.

Association between Circulating Vitamin D Level and Urolithiasis: A Systematic Review and Meta-Analysis

Many studies compared the serum/plasma 1,25 dihydroxyvitamin D₃ (1,25(OH)₂D) and 25 hydroxyvitamin D₃ (25(OH)D) between people with and without nephrolithiasis, and their results were conflicting. After systematically searching PubMed, Web of Science, The Cochrane Library, CNKI, and the Wanfang Database, we conducted a meta-analysis. Thirty-two observational studies involving 23,228 participants were included. Meta-analysis of these studies showed that of stone formers (SFs), calcium SFs had significantly higher concentrations of 1,25(OH)₂D (weighted mean difference (WMD), 10.19 pg/mL; 95% confidence interval (CI), 4.31-16.07; p = 0.0007 and WMD, 11.28 pg/mL; 95% CI, 4.07-18.50; p = 0.002, respectively) than non-stone formers, while the levels of 25(OH)D (WMD, 0.88 ng/mL; 95% CI, -1.04-2.80; p = 0.37 and WMD, -0.63 ng/mL; 95% CI, -2.72-1.47; p = 0.56, respectively) are similar. Compared with controls and normocalciuria SFs, hypercalciuria SFs had increased circulating 1,25(OH)₂D (WMD, 9.41 pg/mL; 95% CI, 0.15-18.67; p = 0.05 and WMD, 2.75 pg/mL; 95% CI, -0.20-5.69; p = 0.07, respectively) and markedly higher 25(OH)D (WMD, 5.02 ng/mL; 95% CI, 0.99-9.06; p = 0.01 and WMD, 5.02 ng/mL; 95% CI, 2.14-7.90; p = 0.0006, respectively). Normocalciuria SFs had elevated 1,25(OH)₂D level (WMD, 6.85 pg/mL; 95% CI, -5.00-18.71; p = 0.26) and comparable 25(OH)D (WMD, 0.94 ng/mL; 95% CI, -3.55-5.43; p = 0.68). Sensitivity analysis generated similar results. Current evidence suggests that increased circulating 1,25(OH)₂D is associated with urinary stones and a higher level of circulating 25(OH)D is significantly associated with hypercalciuria urolithiasis. Further studies are still needed to reconfirm and clarify the role of vitamin D in the pathogenesis of stones.

Association of MMP-9 gene polymorphisms with nephrolithiasis patients

BACKGROUND

Nephrolithiasis is one of the causes which lead to chronic kidney disease (CKD). Matrix metalloproteinases (MMPs) are endopeptidases degrading extracellular matrix which correlate with the pathogenesis of atherosclerosis. The current study was designed to analyze the association of (R279Q, C1562T) polymorphism of MMP-9 with nephrolithiasis patients.

METHODS

Genotyping of MMP-9/R279Q and of MMP-9/C1562T polymorphism were carried out by PCR-based restriction digestion method. Serum level of MMP-9, oxidative stress marker, MDA, and uric acid were measured in patients and control.

RESULTS

Allele frequencies of the MMP-9/C1562T polymorphism for C and T allele were 71.25% and 28.75% in patients, 87.08% and 12.92% in control respectively. The homozygote TT was more frequent in the nephrolithiasis patients group, while T allele frequency was significantly higher in the nephrolithiasis patients group than in the control group. The patients with CT and TT genotype showed a significant increase in serum MMP-9, Total Oxidant Status (TOS), Oxidative Stress Index (OSI), Malondialdehyde (MDA), and uric acid when compared to CC genotype in patients with nephrolithiasis. The R279Q polymorphism site with regard to the relationship with nephrolithiasis was not significant.

CONCLUSION

The result indicates that patients with TT genotype had an increased risk of stones. Also, the results demonstrate that TT allele of the C1562T polymorphism in the MMP-9gene is related with an increase of oxidative stress in nephrolithiasis patients and may possibly impose a risk for cardiovascular diseases in patients with TT genotype of MMP-9.

Reproducibility of a novel computed-tomography based measurement of renal papillary density in the Framingham Heart Study

BACKGROUND

Renal papillary calcification is a compelling candidate risk factor for chronic kidney disease (CKD) and nephrolithiasis. Renal papillary density (RPD), as assessed by computed tomography (CT), is a potential marker for calcification that has not been well studied. We developed a protocol to measure RPD using CT scans and assessed its reproducibility in participants from the Framingham Heart Study.

METHODS

We assessed RPD of right kidneys from a single abdominal CT slice in 100 representative participants from the Framingham Heart Study (47% female, mean age 59.9 years) using a novel protocol. We selected the kidney slice with the most open sinus space and assessed RPD using the average of three 20 mm(2) ellipses from upper, middle and lower papillary regions. Two different readers performed RPD measurements and the first reader repeated all measurements to determine both intra- and inter-reader reproducibility, respectively.

RESULTS

Of 100 total individuals included in the replication dataset, six were excluded for poor scan quality. Average RPD across all individuals was 48.7 ± 4.7 (range 38.7-61.7) Hounsfield Units (HU). The intra- and inter-reader correlation coefficients were 0.86 and 0.79, respectively. Bland-Altman analysis suggested no systematic bias between the different reads.

CONCLUSION

Measuring RPD is practical and reproducible using MDCT scans from a small sample of a community-based cohort.