A novel bioreactor to simulate urinary bladder mechanical properties and compliance for bladder functional tissue engineering / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Bioreactors are pivotal tools for generating mechanical stimulation in functional tissue engineering study. This study aimed to create a bioreactor that can simulate urinary bladder mechanical properties, and to investigate the effects of a mechanically stimulated culture on urothelial cells and bladder smooth muscle cells.</p><p><b>METHODS</b>We designed a bioreactor to simulate the mechanical properties of bladder. A pressure-record system was used to evaluate the mechanical properties of the bioreactor by measuring the pressure in culture chambers. To test the biocompatibility of the bioreactor, viabilities of urothelial cells and smooth muscle cells cultured in the bioreactor under static and mechanically changed conditions were measured after 7-day culture. To evaluate the effect of mechanical stimulations on the vital cells, urethral cells and smooth muscle cells were cultured in the simulated mechanical conditions. After that, the viability and the distribution pattern of the cells were observed and compared with cells cultured in non-mechanical stimulated condition.</p><p><b>RESULTS</b>The bioreactor system successfully generated waveforms similar to the intended programmed model while maintaining a cell-seeded elastic membrane between the chambers. There were no differences between viabilities of urothelial cells ((91.90 ± 1.22)% vs. (93.14 ± 1.78)%, P > 0.05) and bladder smooth muscle cells ((93.41 ± 1.49)% vs. (92.61 ± 1.34)%, P > 0.05). The viability of cells and tissue structure observation after cultured in simulated condition showed that mechanical stimulation was the only factor affected cells in the bioreactor and improved the arrangement of cells on silastic membrane.</p><p><b>CONCLUSIONS</b>This bioreactor can effectively simulate the physiological and mechanical properties of the bladder. Mechanical stimulation is the only factor that affected the viability of cells cultured in the bioreactor. The bioreactor can change the growth behavior of urothelial cells and bladder smooth muscle cells, resulting in the cells undergoing adaptive changes in mechanically-stimulated environment.</p>

Safety and efficacy of laser and cold knife urethrotomy for urethral stricture / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Endoscopic treatment for urethral stricture, including cold knife and laser, poses a major challenge to clinical practice. Both the benefits and drawbacks of these two treatments remain controversial. This article aimed to compare the efficacy and safety of laser and cold knife urethrotomy for urethral stricture.</p><p><b>METHODS</b>We searched PubMed (1966 - 2009), Embase (1980 - 2009), Cochrane Central Register of Controlled Trials (CCRCT, 2009 No.1) and Chinese Biomedical Literature Database (CBM) for laser and cold knife urethrotomy as treatment for male urethral stenosis, looking in the English literatures. Two reviewers independently screened the literatures and extracted information. Chi-square test was used for statistical analysis with SPSS15.0.</p><p><b>RESULTS</b>A total of 44 articles, including of 3230 cases was retrieved. Success rate of patients treated with laser was 74.9% compared with 68.5% for cold knife, with very similar clinical results despite a statistically significant difference (P = 0.004). The trend in success rate at a different follow-up time was similar between the two groups. No significant difference in success rate was found between the groups of repeat operation for recurrence cases, first P = 0.090 and second P = 0.459. The shorter the stricture length was (< 1 cm), the higher the success rate was (P < 0.0001). No significant difference in success rate between the laser and cold knife groups was found in neither bulbar nor membranous urethra, bulbar P = 0.660 and membranous P = 0.477. The rates of urinary incontinence, urinary extravasation, and urinary tract infection showed no significant difference (P = 0.259, P = 0.938, P = 0.653, respectively).</p><p><b>CONCLUSIONS</b>Success rates for laser and cold knife were very similar despite being statistically different, with the groups having a similar trend in success rates at different follow-up time. Stricture location and history of endoscopic intervention did impact treatment outcome but was not significantly different. The two groups showed no significant difference in major complications.</p>

Urethral acellular matrix graft for repairing urethral defect in rabbits / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the biocompatibility of a urethral acellular matrix graft (UAMG) and evaluate its effect in repairing urethral defect in rabbit models.</p><p><b>METHODS</b>The UAMG was prepared and its structural features were observed using optical and electron microscopy. In vitro cultured rabbit bladder smooth muscle cells were seeded on UAMG and the cell proliferation was observed. The cytotoxicity of the aqueous extract of the UAMG against the cells was evaluated by MTT assay, and its biocompatibility was assessed by implanting the grafts subcutaneously on the back of the rabbits. In 24 male rabbits, a 2-cm urethral defect was induced and repaired with UAMG (experimental group, n=12) or left untreated (control group, n=12). In both groups, the rabbits were sacrificed 2, 4, 8 and 12 weeks after the operation for histological and immunohistochemical examination of the tissue regeneration.</p><p><b>RESULTS</b>The UAMG had a reticular fibrous structure without cell residues. The bladder smooth muscle cells showed normal proliferation on UAMG with normal cell morphology. The rabbits receiving the implants showed no abnormal response, and the UAMGs gradually degraded in vivo with grade 0 or 1 cytotoxcity showing satisfactory cytocompatibility. In the experimental group, new urethral tissues that were histologically compatible with normal urethral tissues were regenerated in the defect area 12 weeks after UAMG implantation.</p><p><b>CONCLUSION</b>As a tissue engineered scaffold material for urethral reconstruction, the UAMG possesses good biocompatibility and can induce the regeneration of urethral epithelial cells and smooth muscle cells.</p>

Construction of tissue-engineered urothelial tissue in vitro and in vivo with bladder acellular matrix as scaffold / 中南大学学报(医学版)

OBJECTIVE@#To investigate the construction of urothelial structure by tissue engineering.@*METHODS@#Fresh bladder of New Zealand white rabbits were processed to prepare the bladder acellular matrix graft (BAMG) as the scaffold, which was evaluated by Masson's trichrome staining and the scanning electronic microscope. Bladder epithelia were obtained by enzymatic digestion and were proliferated in vitro. Growth of cells was observed under the inverted phase contrast microscope, and cells were identified by immunohistochemical method. The bladder epithelia were seeded on BAMG, and the epithelia/BAMG composites were observed by HE staining and the scanning electronic microscope. The composites fabricated in vitro were implanted into nude rats, and were retrieved in 4 and 8 weeks, which were observed by general observation, histological and immunohistochemical method.@*RESULTS@#White semi-transparent membrane appeared in the prepared BAMG, and a fibre mesh structure of the material without residual cells was observed under the scanning electronic microscope. Bladder epithelia cultured in vitro showed a paving stone structure. Immunohistochemical staining with cytokeratin was performed, and brown cellular plasma staining was observed as positive reaction. After the epithelia were seeded on BAMG in vitro for 7 days, the cells fully covered the surface of the framework, showing a single-layer cellular structure. After being implanted into nude rats for 4 weeks and 8 weeks, the epithelia seeded on the BAMG formed a multi-layer structure.@*CONCLUSION@#Urothelial structures can be constructed in vitro and in vivo by tissue engineering, which lays a technical foundation for further tissue engineered urinary tract reconstruction experiments.