Identification of Two Clusters in Renal Pelvis Urobiome of Unilateral Stone Formers Using 2bRAD-M.

Urolithiasis is a common urological disease with increasing incidence and a high recurrence rate, whose etiology is not fully understood. The application of sequencing and culturomics has revealed that urolithiasis is closely related to the urinary microbiome (urobiome), shedding new light on the pathogenesis of stone formation. In this study, we recruited 30 patients with unilateral stones and collected their renal pelvis urine from both sides. Then, we performed 2bRAD-M, a novel sequencing technique that provides precise microbial identification at the species level, to characterize the renal pelvis urobiome of unilateral stone formers in the both sides. We first found that the urobiome in the stone side could be divided into two clusters (Stone1 and Stone2) based on distance algorithms. Stone2 harbored higher microbial richness and diversity compared to Stone1. The genera Cupriavidus and Sphingomonas were overrepresented in Stone1, whereas Acinetobacter and Pseudomonas were overrepresented in Stone2. Meanwhile, differential species were identified between Stone1 and Stone2. We further constructed a random forest model to discriminate two clusters which achieved a powerful diagnostic potential. Moreover, the urobiome of the non-stone side (Control1/2) was compared with that of the stone side (Stone1/2). Stone1 and Control1 showed different microbial community distributions, while Stone2 was similar to Control2 based on diversity analysis. We also identified differentially abundant species among all groups. We assumed that there might be different mechanisms of how microbiota contribute to stone formation in two clusters. Our findings might assist in the selection of suitable medical treatments for urolithiasis.

The role of microbiome: a novel insight into urolithiasis.

Urolithiasis, referred to as the formation of stones in the urinary tract, is a common disease with growing prevalence and high recurrence rate worldwide. Although researchers have endeavoured to explore the mechanism of urinary stone formation for novel effective therapeutic and preventative measures, the exact aetiology and pathogenesis remain unclear. Propelled by sequencing technologies and culturomics, great advances have been made in understanding the pivotal contribution of the human microbiome to urolithiasis. Indeed, there are diverse and abundant microbes interacting with the host in the urinary tract, overturning the dogma that urinary system, and urine are sterile. The urinary microbiome of stone formers was clearly distinct from healthy individuals. Besides, dysbiosis of the intestinal microbiome appears to be involved in stone formation through the gut-kidney axis. Thus, the human microbiome has potential significant implications for the aetiology of urolithiasis, providing a novel insight into diagnostic, therapeutic, and prognostic strategies. Herein, we review and summarize the landmark microbiome studies in urolithiasis and identify therapeutic implications, challenges, and future perspectives in this rapidly evolving field. To conclude, a new front has opened with the evidence for a microbial role in stone formation, offering potential applications in the prevention, and treatment of urolithiasis.

Flank suspended supine position for percutaneous nephrolithotomy.

AIMS: Prone and supine positions for percutaneous nephrolithotomy are widely used but have their drawbacks. We report a new positioning method called "flank suspended supine position" (FSSP) for PCNL and describe our experience with PCNL in this position to evaluate its safety and efficacy. METHODS: Retrospective study of 150 cases of renal stone patients treated with PCNL in a new position called flank suspended supine position (FSSP) from June 2009 to July 2010. All patients were treated with PCNL in FSSP under epidural anesthesia. Operation time, bleeding rate, stone free rate, and complications were recorded. RESULTS: All patients tolerated FSSP. Mean operation time was 78.29±26.13 min. Initial stone-free rate was 83%. For those with residual stones (26 cases), 18 were stone-free after a second PCNL, 8 after extracorporeal shock wave lithotripsy (ESWL). Mean hospital stay was 7.63±2.39 days. No penetrating injury of the pleural cavity or injury to visceral organs was reported. SUMMARY: FSSP is an effective and safe position for PCNL in our hands and its effectiveness relative to traditional prone position needs to be determined in future randomized studies.