Osteopontin phosphopeptide mitigates calcium oxalate stone formation in a Drosophila melanogaster model.

Kidney stone disease affects nearly one in ten individuals and places a significant economic strain on global healthcare systems. Despite the high frequency of stones within the population, effective preventative strategies are lacking and disease prevalence continues to rise. Osteopontin (OPN) is a urinary protein that can inhibit the formation of renal calculi in vitro. However, the efficacy of OPN in vivo has yet to be determined. Using an established Drosophila melanogaster model of calcium oxalate urolithiasis, we demonstrated that a 16-residue synthetic OPN phosphopeptide effectively reduced stone burden in vivo. Oral supplementation with this peptide altered crystal morphology of calcium oxalate monohydrate (COM) in a similar manner to previous in vitro studies, and the presence of the OPN phosphopeptide during COM formation and adhesion significantly reduced crystal attachment to mammalian kidney cells. Altogether, this study is the first to show that an OPN phosphopeptide can directly mitigate calcium oxalate urolithiasis formation in vivo by modulating crystal morphology. These findings suggest that OPN supplementation is a promising therapeutic approach and may be clinically useful in the management of urolithiasis in humans.

New perspectives on an old grouping: The genomic and phenotypic variability of Oxalobacter formigenes and the implications for calcium oxalate stone prevention.

Oxalobacter formigenes is a unique bacterium with the ability to metabolize oxalate as a primary carbon source. Most kidney stones in humans are composed of calcium and oxalate. Therefore, supplementation with an oxalate-degrading bacterium may reduce stone burden in patients suffering from recurrent calcium oxalate-based urolithiasis. Strains of O. formigenes are divided into two groups: group I and group II. However, the differences between strains from each group remain unclear and elucidating these distinctions will provide a better understanding of their physiology and potential clinical applications. Here, genomes from multiple O. formigenes strains underwent whole genome sequencing followed by phylogenetic and functional analyses. Genetic differences suggest that the O. formigenes taxon should be divided into an additional three species: Oxalobacter aliiformigenes sp. nov, Oxalobacter paeniformigenes sp. nov, and Oxalobacter paraformigenes sp. nov. Despite the similarities in the oxalyl-CoA gene (oxc), which is essential for oxalate degradation, these strains have multiple unique genetic features that may be potential exploited for clinical use. Further investigation into the growth of these strains in a simulated fecal environment revealed that O. aliiformigenes strains are capable of thriving within the human gut microbiota. O. aliiformigenes may be a better therapeutic candidate than current group I strains (retaining the name O. formigenes), which have been previously tested and shown to be ineffective as an oral supplement to mitigate stone disease. By performing genomic analyses and identifying these novel characteristics, Oxalobacter strains better suited to mitigation of calcium oxalate-based urolithiasis may be identified in the future.

Oxalate-Degrading Bacillus subtilis Mitigates Urolithiasis in a Drosophila melanogaster Model.

Kidney stones affect nearly 10% of the population in North America and are associated with high morbidity and recurrence, yet novel prevention strategies are lacking. Recent evidence suggests that the human gut microbiota can influence the development of nephrolithiasis, although clinical trials have been limited and inconclusive in determining the potential for microbially based interventions. Here, we used an established Drosophila melanogaster model of urolithiasis as a high-throughput screening platform for evaluation of the therapeutic potential of oxalate-degrading bacteria in calcium oxalate (CaOx) nephrolithiasis. The results demonstrated that Bacillus subtilis 168 (BS168) is a promising candidate based on its preferential growth in high oxalate concentrations, its ability to stably colonize the D. melanogaster intestinal tract for as long as 5 days, and its prevention of oxalate-induced microbiota dysbiosis. Single-dose BS168 supplementation exerted beneficial effects on D. melanogaster for as long as 14 days, decreasing stone burden in dissected Malpighian tubules and fecal excreta while increasing survival and behavioral markers of health over those of nonsupplemented lithogenic controls. These findings were complemented by in vitro experiments using the established MDCK renal cell line, which demonstrated that BS168 pretreatment prevented increased CaOx crystal adhesion and aggregation. Taking our results together, this study supports the notion that BS168 can functionally reduce CaOx stone burden in vivo through its capacity for oxalate degradation. Given the favorable safety profile of many B. subtilis strains already used as digestive aids and in fermented foods, these findings suggest that BS168 could represent a novel therapeutic adjunct to reduce the incidence of recurrent CaOx nephrolithiasis in high-risk patients.IMPORTANCE Kidney stone disease is a morbid condition that is increasing in prevalence, with few nonsurgical treatment options. The majority of stones are composed of calcium oxalate. Unlike humans, some microbes can break down oxalate, suggesting that microbial therapeutics may provide a novel treatment for kidney stone patients. This study demonstrated that Bacillus subtilis 168 (BS168) decreased stone burden, improved health, and complemented the microbiota in a Drosophila melanogaster urolithiasis model, while not exacerbating calcium oxalate aggregation or adhesion to renal cells in vitro These results identify this bacterium as a candidate for ameliorating stone formation; given that other strains of B. subtilis are components of fermented foods and are used as probiotics for digestive health, strain 168 warrants testing in humans. With the severe burden that recurrent kidney stone disease imposes on patients and the health care system, this microbial therapeutic approach could provide an inexpensive therapeutic adjunct.

Population-based assessment of re-treatment and healthcare utilisation after photoselective vaporisation of the prostate or electrosurgical transurethral resection of the prostate.

OBJECTIVE: To compare the healthcare utilisation and repeat surgical treatment rate amongst older men undergoing an electrosurgical-transurethral resection of the prostate (TURP) vs photoselective vaporisation of the prostate (PVP), as the real-world implementation and outcomes of laser-based treatment have not been well studied. PATIENTS AND METHODS: We used administrative data from the province of Ontario, Canada, to identify all men aged >66 years who underwent their first electrosurgical-TURP/PVP between 2003 and 2016. Our primary exposure was type of procedure (PVP or electrosurgical-TURP). Our primary outcome was need for repeat surgical treatment. The primary analysis was an adjusted marginal Cox model approach, which accounted for clustering of patients within surgeons; adjusted hazard ratios (aHRs) or odds ratios (aORs) and 95% confidence intervals (CIs) are reported. RESULTS: We identified 52 748 men: 6838 (13%) underwent PVP, and 45 910 (87%) underwent electrosurgical-TURP. The median age was similar, and PVP became more common with time. Compared to the PVP group, more patients in the electrosurgical-TURP group had prior gross haematuria or urinary retention, and fewer had used anticoagulants, α-blockers, or 5α-reductase inhibitors. The need for repeat surgical treatment was significantly higher amongst men who had PVP (aHR 1.57, 95% CI 1.38-1.78; absolute risk difference +2.3%). PVP was also associated with a slightly higher risk of return to the emergency room within 30 days (aOR 1.11, 95% CI 1.01-1.22) and a significantly lower risk of blood transfusion (aOR 0.24, CI 0.16-0.37); the majority of PVP cases were done with a <24 h stay (73%) vs electrosurgical-TURP (7%). CONCLUSIONS: While some of the expected benefits of PVP (such as reduced transfusion risk and shorter length of stay) were observed, the significantly higher rate of repeat surgical treatment compared to electrosurgical-TURP may represent an important difference in implementation of this technology outside of clinical trials.

Drosophila melanogaster as a function-based high-throughput screening model for antinephrolithiasis agents in kidney stone patients.

Kidney stone disease involves the aggregation of stone-forming salts consequent to solute supersaturation in urine. The development of novel therapeutic agents for this predominantly metabolic and biochemical disorder have been hampered by the lack of a practical pre-clinical model amenable to drug screening. Here, Drosophila melanogaster, an emerging model for kidney stone disease research, was adapted as a high-throughput functional drug screening platform independent of the multifactorial nature of mammalian nephrolithiasis. Through functional screening, the therapeutic potential of a novel compound commonly known as arbutin that specifically binds to oxalate, a key component of kidney calculi, was identified. Through isothermal titration calorimetry, high-performance liquid chromatography and atomic force microscopy, arbutin was determined to interact with calcium and oxalate in both free and bound states, disrupting crystal lattice structure, growth and crystallization. When used to treat patient urine samples, arbutin significantly abrogated calculus formation in vivo and outperformed potassium citrate in low pH urine conditions, owing to its oxalate-centric mode of action. The discovery of this novel antilithogenic compound via D. melanogaster, independent of a mammalian model, brings greater recognition to this platform, for which metabolic features are primary outcomes, underscoring the power of D. melanogaster as a high-throughput drug screening platform in similar disorders. This is the first description of the use of D. melanogaster as the model system for a high-throughput chemical library screen. This article has an associated First Person interview with the first authors of the paper.

Effects of subinhibitory concentrations of ciprofloxacin on Staphylococcus saprophyticus adherence and virulence in urinary tract infections.

BACKGROUND AND PURPOSE: Staphylococcus saprophyticus is a frequent cause of both uncomplicated and complicated urinary tract infections (UTI) in young females and has recently been established as the most prominent gram-positive uropathogen. Although the effects of subinhibitory concentrations of antimicrobials on numerous other pathogenic bacteria have been studied, little is known regarding how S saprophyticus responds under such conditions. MATERIALS AND METHODS: In this study, we investigated the effects of subminimum inhibitory concentrations (MIC) of ciprofloxacin (CIP) on S saprophyticus attachment to glass microscope slides, ureteral stent material, and T24 bladder cells, as well as its effects on S saprophyticus-induced proinflammatory cytokine expression in bladder cells. RESULTS: Adherence to glass microscope slides, ureteral stent material, and bladder cell monolayers were all significantly increased in the presence of sub-MIC levels of CIP. While the S saprophyticus challenge of T24 bladder cell monolayers significantly upregulated both interleukin (IL)-6 and IL-8 expression, sub-MIC CIP abrogated these effects, returning their secretion to control levels. CONCLUSIONS: Our results demonstrate that exposure to sub-MIC CIP increases S saprophyticus adherence to both abiotic and biotic surfaces including urinary device material and cultured bladder cells. In addition, low levels of this antimicrobial downregulate S saprophyticus-stimulated proinflammatory cytokine secretion in the bladder. These changes may make S saprophyticus more effective at colonizing the urinary tract and highlights the need for clinicians to consider the impact of subinhibitory concentrations of antimicrobials on bacteria when designing treatment strategies to manage UTI.

Dong Quai (angelica sinensis) in the treatment of hot flashes for men on androgen deprivation therapy: results of a randomized double-blind placebo controlled trial.

OBJECTIVE: To determine whether Dong Quai, a Chinese herbal compound purported to be efficacious in treating menopausal vasomotor symptoms, has a therapeutic benefit in treating hot flashes among prostate cancer patients receiving androgen deprivation therapy. METHODS: A randomized double-blind placebo controlled trial was conducted involving 22 men receiving luteinizing hormone-releasing hormone agonist therapy for prostate cancer with bothersome hot flashes. After recording a baseline log of the frequency, duration and severity of daily hot flashes, patients were randomly assigned in a 1:1 ratio to receive daily placebo or Dong Quai for 3 months. Vasomotor and adverse events were recorded daily. Blood work including serum prostate-specific antigen (PSA), international normalized ratio of prothrombin time and partial thromoboplastin time were recorded at baseline and at the termination of the study. RESULTS: Seventeen of the 22 patients enrolled completed the trial. Baseline vasomotor duration and severity were equivalent between the groups, however the number of hot flashes were significantly more in the Dong Quai group (p = 0.02). With respect to the change in number of hot flashes per day, there was a slight decrease in the mean number among the Dong Quai group which was insignificant. The absolute change and average percentage change in perceived hot flash severity was similar in both groups. There was no significant decrease in the duration of the hot flashes between the 2 groups. Disease progression based on either PSA increase or change in digital rectal exam was not observed in any patient. CONCLUSION: In this small pilot study, there were no significant differences in the severity, frequency or duration of hot flashes among men receiving placebo or Dong Quai.

Comparison of the thermal and histopathological effects of bipolar and monopolar electrosurgical resection of the prostate in a canine model.

OBJECTIVES: To compare the thermal and histopathological effects of two commercially available bipolar systems and conventional monopolar transurethral resection of the prostate (TURP) in a canine model. Bipolar TURP is an alternative to monopolar electrosurgery for treating benign prostatic hyperplasia and has several potential clinical advantages, including the ability to use normal saline irrigation, enhanced haemostasis and less collateral thermal damage. MATERIAL AND METHODS: In all, 12 adult male beagles were studied. After midline laparotomy and exposure of the bladder and prostate, two fibre-optic thermosensors were placed to record tissue temperatures; one sensor was placed into the substance of the prostate 2 cm from the urethra and the second in the prostatic-rectal groove on the capsular surface of the prostate to measure temperatures in the region of the neurovascular bundles. Through a midline cystotomy, antegrade TURP was performed using two different bipolar systems (Gyrus PlasmaKinetic and Vista, both from Gyrus-ACMI Corporation, Maple Grove, MN, USA) or a monopolar device (Force(TM) 2, Valleylab, Boulder, CO, USA). TURP was performed in each lateral lobe using 24 F resection loops. The dogs were humanely killed acutely and the prostates excised for histopathological assessment. RESULTS: When comparing intraprostatic temperature data, the mean (sem) temperature changes recorded for the monopolar group were significantly higher than in either the Gyrus or Vista bipolar groups, at 24.2 (3.9) degrees C vs 8.1 (1.5) degrees C and 6.8 (1.8) degrees C, respectively (P < 0.001). No measurable temperature elevations were recorded near the neurovascular bundles with any of the electrosurgery devices. The depth of thermal damage was greatest in the monopolar group at 0.59 (0.27) mm compared with the Gyrus and Vista groups at 0.07 (0.08) mm and 0.15 (0.02) mm, respectively (P < 0.001). CONCLUSION: Bipolar TURP generated significantly less heat and histopathological evidence of thermal damage compared with monopolar TURP in the present canine model.

Percutaneous nephrolithotomy under conscious sedation in morbidly obese patients.

Two morbidly obese males weighing 159 kg and 184 kg underwent percutaneous nephrolithotomy (PCNL) for large, symptomatic renal stones. To avoid anesthetic complications and cardiorespiratory compromise in the prone position, the procedures were performed under IV sedation with local anesthesia. The risks of PCNL in this patient population are reviewed, and the technique employed to mitigate the risks in these two cases is described.

Long-term results of microwave thermotherapy for symptomatic benign prostatic hyperplasia.

PURPOSE: To study the long-term outcomes of men with moderately severe symptomatic benign prostatic hyperplasia (BPH) who were treated with transurethral microwave thermotherapy (TUMT) with the Dornier Urowave machine. PATIENTS AND METHODS: A total of 220 patients (mean age 66.2 years) with clinical BPH, an American Urological Association (AUA) Symptom Score of >or=13, and a peak urinary flow rate (Qmax) of