Impact of the Human Microbiome on Nephrolithiasis

Nephrolithiasis has many causes, and its prevalence is increasing worldwide. The interest in the human microbiome is growing because of the advance of new diagnostic techniques, and recent studies have suggested a link between the microbiome and nephrolithiasis. This paper reviewed the role of the microbiome in nephrolithiasis. The absence of Oxalobacter formigenes induces hyperoxaluria, which promotes calcium oxalate stone (CaOx) formation. Escherichia coli promote CaOx supersaturation through hypocitraturia caused by the bacterial production of citrate lyase. Infection stones are associated with urea-splitting organisms, particularly Proteus mirabilis, and the stones themselves contain many species of bacteriaope

Near-Normalized Gene Expression Profiles in Bladder With Detrusor Overactivity in Rats With Bladder Outlet Obstruction After Deobstruction

Purpose: The pathophysiological role of detrusor overactivity (DO) in the bladder, which is commonly observed in various bladder diseases, is not well understood. DO appears in bladder outlet obstruction (BOO), and may continue even after subsequent deobstruction. DO therefore provides an excellent opportunity to observe molecular biological changes. Methods: In this study, to understand the molecular effects of persistent DO after BOO induction and deobstruction, we performed awake cystometry on female Sprague-Dawley rats divided into 4 groups: a sham group, a BOO group, a deobstructed group with DO after BOO (DDO), and a deobstructed group without DO after BOO (non-DDO). Total RNA was extracted from the bladder samples, and gene expression profiles were compared between the sham and model groups. Results: DO was observed in 5 of the 6 rats (83%) in the BOO group, and in 6 of the 13 rats (46%) in the deobstructed group. The non-DDO group showed a significantly greater residual volume than the DDO group. Through a clustering analysis of gene expression profiles, we identified 7,532 common upregulated and downregulated genes, the expression of which changed by more than 2 fold. In the BOO group, 898 upregulated and 2,911 downregulated genes were identified. The non-DDO group showed 3,472 upregulated and 4,025 downregulated genes, whereas in the DDO group, only 145 and 72 genes were upregulated and downregulated, respectively. Conclusions: Abnormal function and gene expression profiles in bladders after BOO were normalized in the BOO rats with DO after deobstruction, whereas in those without DO, abnormal function persisted and the gene expression profile became more abnormal. DO may play a protective role against the stress to the bladder induced by BOO and deobstruction as a form of adaptive neuroplasticity.ope

Preoperative Underweight Patients with Upper Tract Urothelial Carcinoma Survive Less after Radical Nephroureterectomy

The prognostic impact of body mass index (BMI) in patients with upper tract urothelial carcinoma (UTUC) is an ongoing debate. Our study aimed to investigate the prognostic role of BMI in patients treated with radical nephroureterectomy (RNU) for UTUC from a multi-institutional Korean collaboration. We retrospectively reviewed data from 440 patients who underwent RNU for UTUC at four institutions in Korea. To avoid biasing the survival estimates, patients who had previous or concomitant muscle-invasive bladder tumors were excluded. BMI was categorized into approximate quartiles with the lowest quartile assigned to the reference group. Kaplan-Meier and multivariate Cox regression analyses were performed to assess the influence of BMI on survival. The lower quartile BMI group showed significantly increased overall mortality (OM) and cancer specific mortality (CSM) compared to the 25%-50% quartiles and upper quartile BMI groups. Kaplan-Meier estimates showed similar results. Based on multivariate Cox regression analysis, preoperative BMI as a continuous variable was an independent predictor for OM and CSM. In conclusion, preoperative underweight patients with UTUC in Korea survive less after RNU. Preoperative BMI may provide additional prognostic information to establish risk factors.ope

Neonatal Bladder Irritation Is Associated With Vanilloid Receptor TRPV1 Expression in Adult Rats.

PURPOSE: To evaluate whether mild chemical irritation of the bladder in neonatal rats is associated with persistent vanilloid receptor transient receptor potential vanilloid subfamily 1 (TRPV1) activity in adult rats. METHODS: Female Sprague-Dawley rats were used. Ten-day-old rat pups underwent bladder sensitization via intravesical infusion of 0.2% acetic acid in saline with or without prior bladder desensitization with capsaicin. After 8 weeks, 3 groups of rats (control [group 1], bladder sensitization [group 2], and bladder desensitization [group 3]) underwent cystometry. Inflammation of bladder tissue and the expression of TRPV1 in bladder tissue and dorsal root ganglia (DRG) were also evaluated. RESULTS: The bladder sensitization group showed more frequent voiding contractions. TRPV1 expression in adult bladder tissue was elevated in group 2. TRPV1 mRNA levels in the bladder and DRG were significantly higher in group 2 than in group 1. Moreover, group 2 had significantly more DRG neurons (identified by uptake of the retrograde label Fast Blue) that exhibited TRPV1 immunoreactivity. CONCLUSION: We found a significant association between neonatal bladder sensitization and persistent TRPV1 activity in adult rats. This is the first study to focus on the underlying pathogenesis of bladder overactivity from childhood to adulthood. Our findings could lead to the development of new strategies for the treatment and prevention of adult urinary symptoms arising from childhood urinary tract dysfunction.ope

Prediction of organ-confined disease after robot-assisted radical prostatectomy in patients with clinically locally-advanced prostate cancer

BACKGROUND: Little is known about the preoperative predictive factors that could identify subsets of favorable patients who can be possibly cured with robot-assisted radical prostatectomy (RARP) alone in locally advanced prostate cancer (LAPCa). Our study was designed to identify clinical predictors of pathologic organ-confined disease (pOCD) in RARP setting. METHODS: Between 2007 and 2013, clinicopathological and oncological data from 273 consecutive men undergoing robot-assisted RP with extended PLND for clinically LAPCa were reviewed in a single-institution, retrospectively. After exclusion of patients who received neoadjuvant hormone treatment before surgery, 186 subjects satisfied the final inclusion criteria. RESULTS: Fourty-three patients (23.1% of total cohort) with preoperative clinically LAPCa patients were down-staged to pOCD following RARP. Preoperative prostate-specific antigen (PSA) level, preoperative PSAD, positive core percent, maximal tumor volume in any core, and biopsy Gleason score were significantly associated with down-staging into pOCD following RARP. Multivariate logistic regression analysis revealed that lower preoperative PSA (≤10 ng/mL) and maximal tumor volume in any core (≤70%) were independent predictors of pOCD following RARP. CONCLUSIONS: Approximately 23% of preoperative clinically LAPCa patients were down-staged to pOCD following RARP. Preoperative PSA and maximal tumor volume in any biopsy core might be useful clinical predictors of pOCD in clinically LAPCa patients in RARP setting.ope

Comparison of stone-free rates following shock wave lithotripsy, percutaneous nephrolithotomy, and retrograde intrarenal surgery for treatment of renal stones: A systematic review and network meta-analysis

OBJECTIVES: To perform a systematic review and network meta-analysis comparing stone-free rates following retrograde intrarenal surgery (RIRS), extracorporeal shock wave lithotripsy (SWL), and percutaneous nephrolithotomy (PCNL) treatments of renal stones. MATERIALS AND METHODS: Clinical trials comparing RIRS, SWL, and PCNL for treatment of renal stones were identified from electronic databases. Stone-free rates for the procedures were compared by qualitative and quantitative syntheses (meta-analyses). Outcome variables are shown as risk ratios (ORs) with 95% credible intervals (CIs). RESULTS: A total of 35 studies were included in this network meta-analysis of success and stone-free rates following three different treatments of renal stones. Six studies compared PCNL versus SWL, ten studies compared PCNL versus RIRS, fourteen studies compared RIRS versus SWL, and five studies compared PCNL, SWL, and RIRS. The quality scores within subscales were relatively low-risk. Network meta-analyses indicated that stone-free rates of RIRS (OR 0.38; 95% CI 0.22-0.64) and SWL (OR 0.12; 95% CI 0.067-0.19) were lower than that of PCNL. In addition, stone-free rate of SWL was lower than that of RIRS (OR 0.31; 95% CI 0.20-0.47). Stone free rate of PCNL was also superior to RIRS in subgroup analyses including ≥ 2 cm stone (OR 4.680; 95% CI 2.873-8.106), lower pole stone (OR 1.984; 95% CI 1.043-2.849), and randomized studies (OR 2.219; 95% CI 1.348-4.009). In rank-probability test, PCNL was ranked as No. 1 and SWL was ranked as No. 3. CONCLUSIONS: PCNL showed the highest success and stone-free rate in the surgical treatment of renal stones. In contrast, SWL had the lowest success and stone-free rate.ope

Stone heterogeneity index as the standard deviation of Hounsfield units: A novel predictor for shock-wave lithotripsy outcomes in ureter calculi

We investigated whether stone heterogeneity index (SHI), which a proxy of such variations, was defined as the standard deviation of a Hounsfield unit (HU) on non-contrast computed tomography (NCCT), can be a novel predictor for shock-wave lithotripsy (SWL) outcomes in patients with ureteral stones. Medical records were obtained from the consecutive database of 1,519 patients who underwent the first session of SWL for urinary stones between 2005 and 2013. Ultimately, 604 patients with radiopaque ureteral stones were eligible for this study. Stone related variables including stone size, mean stone density (MSD), skin-to-stone distance, and SHI were obtained on NCCT. Patients were classified into the low and high SHI groups using mean SHI and compared. One-session success rate in the high SHI group was better than in the low SHI group (74.3% vs. 63.9%, P = 0.008). Multivariate logistic regression analyses revealed that smaller stone size (OR 0.889, 95% CI: 0.841-0.937, P < 0.001), lower MSD (OR 0.995, 95% CI: 0.994-0.996, P < 0.001), and higher SHI (OR 1.011, 95% CI: 1.008-1.014, P < 0.001) were independent predictors of one-session success. The radiologic heterogeneity of urinary stones or SHI was an independent predictor for SWL success in patients with ureteral calculi and a useful clinical parameter for stone fragility.ope

Prostate-specific antigen density predicts favorable pathology and biochemical recurrence in patients with intermediate-risk prostate cancer.

This study was designed to identify clinical predictors of favorable pathology and biochemical recurrence (BCR) in patients with intermediate-risk prostate cancer (IRPCa). Between 2006 and 2012, clinicopathological and oncological data from 203 consecutive men undergoing robot-assisted radical prostatectomy (RARP) for IRPCa were reviewed in a single-institutional retrospective study. Favorable pathology was defined as Gleason score ≤6 and organ-confined cancer as detected by surgical pathology. Logistic regression analysis was used to determine predictive variables of favorable pathology, and the Kaplan-Meier and multivariate Cox regression model were used to estimate BCR-free survival after RARP. Overall, 38 patients (18.7%) had favorable pathology after RARP. Lower quartile prostate-specific antigen density (PSAD) was associated with favorable pathology compared to the highest quartile PSAD after adjusting for preoperative PSA, clinical stage and biopsy Gleason score (odds ratio, 5.42; 95% confidence interval, 1.01-28.97; P = 0.048). During a median 37.8 (interquartile range, 24.6-60.2) months of follow-up, 66 patients experienced BCR. There were significant differences with regard to BCR free survival by PSAD quartiles (log rank, P = 0.003). Using a multivariable Cox proportion hazard model, PSAD was found to be an independent predictor of BCR in patients with IRPCa after RARP (hazard ratio, 4.641; 95% confidence interval, 1.109-19.417; P = 0.036). The incorporation of the PSAD into risk assessments might provide additional prognostic information and identify some patients in whom active surveillance would be appropriate in patients with IRPCa.ope

Seasonal Variation of Urinary Symptoms in Korean Men with Lower Urinary Tract Symptoms and Benign Prostatic Hyperplasia

PURPOSE: To examine seasonal variations in urinary symptoms in Korean men with lower urinary tract symptoms and benign prostatic hyperplasia (LUTS/BPH). MATERIALS AND METHODS: Records were obtained from a consecutive database of LUTS/BPH patients from March 2010 to February 2014. A total of 1,185 patients were suitable for analysis. The International Prostate Symptom Score (IPSS), uroflowmetric parameters, prostate volume-related parameters, and serum prostate-specific antigen levels were evaluated. RESULTS: Based on the month during which they were examined, patients were categorized into cold, hot, or intermediate season groups. The IPSS score was significantly different between the cold and the hot season groups (17.3±6.9 vs. 16.1±7.4, respectively; p=0.020). Storage symptom scores were significantly aggravated in the cold (6.8±3.3; p=0.030) and intermediate groups (6.9±3.5; p=0.032) compared with the hot season group (6.3±3.4), with this observation primarily driven by the individual scores for frequency and urgency. Quality of life (QOL) scores were worse in the cold compared with the hot season group (4.0±1.1 vs. 3.8±1.1, respectively; p=0.012). There were also significant differences between the cold and hot season groups in voided volume (278.7±148.5 vs. 255.9±145.1, respectively; p=0.034) and postvoid residual volume (26.4±37.6 vs. 32.2±41.0, respectively; p=0.039). CONCLUSIONS: Different urinary symptoms and uroflowmetric parameters were associated with changes in seasons. QOL and IPSS parameters might be worse in cold weather seasons compared with hot weather seasons.ope

Systematic review and meta-analysis to compare success rates of retrograde intrarenal surgery versus percutaneous nephrolithotomy for renal stones >2 cm: An update.

BACKGROUND: We performed a systematic review and meta-analysis comparing stone-free rates between retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PCNL), using updated, more reliable evidence. MATERIALS AND METHODS: Randomized controlled trials comparing RIRS and PCNL for >2 cm stones were identified from electronic databases. Stone-free rates for the procedures were compared by qualitative and quantitative syntheses (meta-analyses). Outcome variables are shown as risk ratios (RRs) with 95% confidence intervals (CIs). RESULTS: Eleven articles were included in this study. Most recently published studies exhibited relatively low quality during quality assessment. For the meta-analysis comparing success (stone-free) rates between PCNL and RIRS, the forest plot using the random-effects model showed an RR of 1.11 (95% CI 1.02-1.21, P < .014) favoring PCNL. After determining the among-study heterogeneity, subgroup analysis was performed of 9 studies with less heterogeneity: the stone-free rate of PCNL was superior to that of RIRS using a fixed-effect model (RR 1.07, 95% CI 1.01-1.14, P < .019) for these studies. CONCLUSIONS: RIRS can be a safe and effective procedure for selected patients with large renal stones. However, in this meta-analysis, the postoperative stone-free rate of PCNL was higher than that of RIRS in patients with >2 cm renal stones.ope