MiR-133 modulates TGF-ß1-induced bladder smooth muscle cell hypertrophic and fibrotic response: implication for a role of microRNA in bladder wall remodeling caused by bladder outlet obstruction.

Bladder outlet obstruction (BOO) evokes urinary bladder wall remodeling significantly, including the phenotype shift of bladder smooth muscle cells (BSMCs) where transforming growth factor-beta1 (TGF-ß1) plays a pivotal role given the emerging function of modulating cellular phenotype. miR-133 plays a role in cardiac and muscle remodeling, however, little is known about its roles in TGF-ß1-induced BSMC hypertrophic and fibrotic response. Here, we verified BOO induced bladder wall remodeling and TGF-ß1 expression mainly located in bladder endothelium. Furthermore, we uncovered miR-133a/b expression profile in BOO rats, and then explored its regulated effects on BSMCs' phenotypic shift. Our study found that miR-133 became down-regulated during rat bladder remodeling. Next, we sought to examine whether the expression of miR-133 was down-regulated in primary BSMCs in response to TGF-ß1 stimulation and whether forced overexpression of miR-133 could regulate profibrotic TGF-ß signaling. We found that stimulation of BSMCs with exogenous TGF-ß1 of increasing concentrations resulted in a dose-dependent decrease of miR-133a/b levels and transfection with miR-133 mimics attenuated TGF-ß1-induced α-smooth muscle actin, extracellular matrix subtypes and fibrotic growth factor expression, whereas it upregulated high molecular weight caldesmon expression compared with the negative control. Also, downregulation of p-Smad3, not p-Smad2 by miR-133 was detected. Additionally, miR-133 overexpression suppressed TGF-ß1-induced BSMC hypertrophy and proliferation through influencing cell cycle distribution. Bioinformatics analyses predicted that connective tissue growth factor (CTGF) was the potential target of miR-133, and then binding to the 3'-untranslated region of CTGF was validated by luciferase reporter assay. These results reveal a novel regulator for miR-133 to modulate TGF-ß1-induced BSMC phenotypic changes by targeting CTGF through the TGF-ß-Smad3 signaling pathway. A novel antifibrotic functional role for miR-133 is presented which may represent a potential target for diagnostic and therapeutic strategies in bladder fibrosis.

Influence of irrigation on incision and coagulation of 2.0-µm continuous-wave laser: an ex vivo study.

BACKGROUND: Several lasers are suitable for laparoscopic surgery but with remarkable smoke formation, which compromises surgical visibility and safety. Slow irrigation eliminates laser smoke efficiently, but gives rise to the concern of reducing the laser incision and coagulation efficiency. METHODS: Canine kidney specimens were manually cut with a 2-µm continuous-wave Thulium-YAG laser. Two laser powers (20 and 40 W) combined with 3 irrigation rates (0, 20, and 80 mL/min) were experimented. The depth of the cutting slot and the thickness of the coagulation layer were measured microscopically and compared statistically between different setting combinations using 2-way analysis of variance. RESULTS: The incision depth was decreased significantly at high (80 mL/min) but not low rate (20 mL/min). The thickness of the coagulation layer changed insignificantly with the irrigation rate. CONCLUSIONS: Slow irrigation had an acceptable influence on the incision and the coagulation ability of 2.0-µm continuous-wave laser and is suitable and efficient to address the smoke issue in laser laparoscopic surgery.

Ex vivo evaluation of femtosecond pulse laser incision of urinary tract tissue in a liquid environment: implications for endoscopic treatment of benign ureteral strictures.

BACKGROUND: The femtosecond (FS) pulse laser incises soft tissues with minimal peripheral damage and is a promising cutting tool for ureteroscopic endoureterotomy of benign ureteral strictures. OBJECTIVE: To evaluate the feasibility of applying the FS laser to ureteroscopic endoureterotomy. MATERIALS AND METHODS: A commercial Ti:Sapphire regenerative amplifier system (Coherent, RegA 9050, USA) was used in this study. Normal saline, 5% glucose solution, 4% mannitol solution, distilled water, and a 1% (v/v) suspension of whole blood with each of these solutions were tested for their attenuation rate (AR) of the FS laser's power. Bladder specimens from Sprague-Dawley (SD) rats were used as a surrogate model. The laser incised slots of 2 mm in length at bladder samples using three power grades (5×, 10×, and 20× the threshold power) combined with five effective pulse rates (40, 20, 10, 5, and 2.5 kHz), both in air and in normal saline. After samples were processed with standard hematoxylin-eosin staining procedures, the incision depth and collateral damage range were determined microscopically. RESULTS: The ARs of blood suspensions with each of the three isosmotic solutions were significantly higher than the other five solutions (P < 0.001). The FS laser's cutting depth and the collateral damage were increased with the laser power or power density but the collateral damages were less than 100 µm. Microbubble formation was detected in the liquid environments tested and influenced the effective laser power. CONCLUSIONS: Endoscopic application of the FS laser is feasible. Microbubble formation with the laser incision, however, may influence cutting effects. Proposed methods to address these issues include increasing the irrigation rate, using distilled water as irrigation or using gas insufflation instead of irrigation. It is necessary to evaluate these methods, as well as the long-term biologic response to laser incision, on living animal models in endoscopic settings before use on humans.

Irrigation eliminates smoke formation in laser laparoscopic surgery: ex vivo results.

BACKGROUNDS AND OBJECTIVES: To evaluate the desmoke effects of irrigation on surgical smoke generated during laser laparoscopic surgery using ex vivo model. STUDY DESIGN/MATERIALS AND METHODS: A hand-piece was devised as both an irrigation tube and a laser fiber holder. The laser system used was a diode pumped continuous wave Thulium YAG laser (Lisa laser products OHG, Katlenburg-Lindau, Germany) emitting at 2.01-mum through a quartz fiber with a core diameter of 365 mum. Using a transparent container as experimental model (approximately 3 L in volume), 6 irrigation rates (0, 20, 40, 60, 80, and 100 mL/min) were tested combining with 4 laser power settings (20, 30, 40, and 50 W). To evaluate the desmoke efficiency of irrigation, lasing time with effective visibility under different combination of irrigation rates and laser powers were documented, and corresponding smoke generation rate were calculated (=3 L/lasing time). Analysis of variance was used to compare difference and significance was indicated at P<0.05. RESULTS: Calculated smoke generation rate was increased with laser power whereas decreased with irrigation rate. At 4 tested laser powers, calculated smoke generation rates were high (mean: 91.4 to 306.6 mL/s) when no water presented, but were significantly decreased (mean: 12.6 to 55.0 mL/s, P<0.001) with the lowest water flow rate (20 mL/min) and further decreased with higher rates. The proper range of irrigation rate for future clinical practice would be around 40 mL/min. CONCLUSIONS: Irrigation eliminates smoke formation accompanying laser tissue irradiation. It shows promise for future application in laser laparoscopic surgery.