Identification and validation of a gap junction protein related signature for predicting the prognosis of renal clear cell carcinoma.

Background: Gap junction proteins (GJPs) are a class of channel proteins that are closely related to cell communication and tumor development. The objective of this study was to screen out GJPs related prognostic signatures (GRPS) associated with clear cell renal cell carcinoma (ccRCC). Materials and Methods: GJPs microarray data for ccRCC patients were obtained from The Gene Expression Omnibus (GEO) database, along with RNA sequencing data for tumor and paired normal tissues from The Cancer Genome Atlas (TCGA) database. In the TCGA database, least absolute shrinkage and selection Operator (LASSO) and Cox regression models were used to identify GJPs with independent prognostic effects as GRPS in ccRCC patients. According to the GRPS expression and regression coefficient from the multivariate Cox regression model, the risk score (RS) of each ccRCC patient was calculated, to construct the RS prognostic model to predict survival. Overall survival (OS) and progression-free survival (PFS) analyses; gene pan-cancer analysis; single gene survival analysis; gene joint effect analysis; functional enrichment analysis; tumor microenvironment (TME) analysis; tumor mutational burden (TMB) analysis; and drug sensitivity analysis were used to explore the biological function, mechanism of action and clinical significance of GRPS in ccRCC. Further verification of the genetic signature was performed with data from the GEO database. Finally, the cytofunctional experiments were used to verify the biological significance of GRPS associated GJPs in ccRCC cell lines. Results: GJA5 and GJB1, which are GRPS markers of ccRCC patients, were identified through LASSO and Cox regression models. Low expression of GJA5 and GJB1 is associated with poor patient prognosis. Patients with high-RS had significantly shorter OS and PFS than patients with low-RS (p< 0.001). The risk of death for individuals with high-RS was 1.695 times greater than that for those with low-RS (HR = 1.695, 95%CI= 1.439-1.996, p< 0.001). Receiver Operating Characteristic (ROC) curve showed the great predictive power of the RS prognostic model for the survival rate of patients. The area under curve (AUC) values for predicting 1-year, 3-year and 5-year survival rates were 0.740, 0.781 and 0.771, respectively. The clinical column chart was also reliable for predicting the survival rate of patients, with AUC values of 0.859, 0.846 and 0.796 for predicting 1-year, 3-year and 5-year survival, respectively. The GRPS was associated with immune cell infiltration, the TME, the TMB, and sensitivity to chemotherapy drugs. Further in vitro experiments showed that knockdown of GJA5 or GJB1 could promote the proliferation, migration and epithelial-mesenchymal transition (EMT) and inhibit apoptosis of ccRCC cells. Conclusion: GJA5 and GJB1 could be potential biological markers for predicting survival in patients with ccRCC.

Comparison of lateral transperitoneal versus retroperitoneal laparoscopic adrenalectomy for pheochromocytoma: a single-centre retrospective study.

Laparoscopic adrenalectomy (LA) has became the standardized treatment for pheochromocytoma. The aim of this study was to evaluate outcomes of lateral transperitoneal and retroperitoneal LA for pheochromocytoma. Between January 2011 and December 2021, 142 patients with pheochromocytoma underwent LA via lateral transperitoneal (123 patients) or retroperitoneal (19 patients) approaches. Data of these patients were assessed to investigate the differences in perioperative outcomes and intraoperative haemodynamic parameters between the two procedures. Clinical parameters at presentation were comparable between the two groups, except for tumour size, which was larger in the transperitoneal group (50 [10-115] mm vs 35 [7-110] mm, P = 0.012). There were no significant differences between the two groups in terms of operation time, estimated blood loss, intraoperative transfusion rate, incidence of complications, conversion to open surgery, postoperative analgesic requirement, time to first oral intake, or mean hospital stay. Intraoperative haemodynamic parameters of the two groups were similar. After adjusting for tumour size using propensity score matching, both perioperative outcomes and haemodynamic parameters were still comparable. Lateral transperitoneal and retroperitoneal laparoscopic adrenalectomies provide similar perioperative and haemodynamic outcomes for surgical resection of pheochromocytoma.

Risk factors for hemodynamic instability during laparoscopic resection of pheochromocytoma.

BACKGROUND: Laparoscopic adrenalectomy for pheochromocytoma is associated with high risk of intraoperative hemodynamic instability. Our study aimed to identify predictive factors for hemodynamic instability during laparoscopic resection of pheochromocytoma. METHODS: Between January 2011 and December 2021, 136 patients underwent unilateral laparoscopic adrenalectomy for pheochromocytoma. The patients were divided into 2 groups depending on the presence or absence of hemodynamic instability during surgery. Intraoperative hemodynamic parameters were compared between the 2 groups. Patient demographic characteristics and preoperative evaluations were assessed for their prognostic relevance with respect to intraoperative hemodynamic instability via both univariate analysis and multivariate logistic regression analysis. RESULTS: There was greater blood pressure fluctuations and higher maximum blood pressure and heart rate in the hemodynamic instability group. More patients need intraoperative administration of vasoactive drugs in the hemodynamic instability group. In the univariate analysis, presence of coronary artery disease, tumour size, and previous hypertension history were significantly associated with intraoperative hemodynamic instability. The multivariate logistic regression analysis showed that tumour size and previous hypertension history were independent risk factors for intraoperative hemodynamic instability. CONCLUSION: Tumour size and previous hypertension history were associated with hemodynamic instability during laparoscopic resection of pheochromocytoma.

Construction and validation of a prognostic model of RNA binding proteins in clear cell renal carcinoma.

BACKGROUND: The dysfunction of RNA binding proteins (RBPs) is associated with various inflammation and cancer. The occurrence and progression of tumors are closely related to the abnormal expression of RBPs. There are few studies on RBPs in clear cell renal carcinoma (ccRCC), which allows us to explore the role of RBPs in ccRCC. METHODS: We obtained the gene expression data and clinical data of ccRCC from the Cancer Genome Atlas (TCGA) database and extracted all the information of RBPs. We performed differential expression analysis of RBPs. Risk model were constructed based on the differentially expressed RBPs (DERBPs). The expression levels of model markers were examined by reverse transcription-quantitative PCR (RT-qPCR) and analyzed for model-clinical relevance. Finally, we mapped the model's nomograms to predict the 1, 3 and 5-year survival rates for ccRCC patients. RESULTS: The results showed that the five-year survival rate for the high-risk group was 40.2% (95% CI = 0.313 ~ 0.518), while the five-year survival rate for the low-risk group was 84.3% (95% CI = 0.767 ~ 0.926). The ROC curves (AUC = 0.748) also showed that our model had stable predictive power. Further RT-qPCR results were in accordance with our analysis (p < 0.05). The results of the independent prognostic analysis showed that the model could be an independent prognostic factor for ccRCC. The results of the correlation analysis also demonstrated the good predictive ability of the model. CONCLUSION: In summary, the 4-RBPs (EZH2, RPL22L1, RNASE2, U2AF1L4) risk model could be used as a prognostic indicator of ccRCC. Our study provides a possibility for predicting the survival of ccRCC.

Alterations of DNA methylation were associated with the rapid growth of cortisol-producing adrenocortical adenoma during pregnancy.

BACKGROUND: Cortisol-producing adrenocortical adenoma (CPA) during pregnancy rarely occurs in clinic. Growing evidence suggests that DNA methylation plays a key role in adrenocortical adenomas. The present study aims to examine the genome-wide DNA methylation profiles and identify the differences in DNA methylation signatures of non-pregnant and pregnant patients with CPA. RESULTS: Four pregnant and twelve non-pregnant patients with CPA were enrolled. The pregnant patients with CPA had higher serum cortisol, Estradiol, Progesterone, and human chorionic gonadotropin concentration, while having lower serum FSH (follicle-stimulating hormone) and luteinizing hormone concentrations (P < 0.01). Compared with the non-pregnant patients, the duration is shorter, and the growth rate of the tumor is faster in pregnant patients with CPA (P < 0.05). Morphology and cell proliferation assay showed that the percentage of Ki-67 positive cells in CPA were higher in pregnant group than non-pregnant group (8.0% vs 5.5%, P < 0.05). The DNA methylation analysis showed that Genome-wide DNA methylation signature difference between pregnant and non-pregnant with CPA, that the pregnant group had more hypermethylated DMPs (67.94% vs 22.16%) and less hypomethylated DMPs (32.93% vs 77.84%). The proportion of hypermethylated DMPs was relatively high on chromosomes 1 (9.68% vs 8.67%) and X (4.99% vs 3.35%) but lower on chromosome 2(7.98% vs 12.92%). In pregnant patients with CPA, 576 hypomethylated DMPs and 1109 hypermethylated DMPs were identified in the DNA promoter region. Bioinformatics analysis indicated that the Wnt/ß-Catenin pathway, Ras/MAPK Pathway and PI3K-AKT Pathway were associated with the development of CPA during pregnancy. CONCLUSIONS: Genome-wide DNA methylation profiling of CPA in non-pregnant and pregnant patients was identified in the present study. Alterations of DNA methylation were associated with the pathogenesis and exacerbation of CPA during pregnancy.

Comparison of lateral transperitoneal and retroperitoneal approaches for homolateral laparoscopic adrenalectomy.

BACKGROUND: There is a lack of data regarding the appropriateness of transperitoneal and retroperitoneal approaches for homolateral laparoscopic adrenalectomy. The aim of this study is to compare lateral transperitoneal and retroperitoneal approach for left-sided and right-sided laparoscopic adrenalectomy respectively. METHODS: Between January 2014 and December 2019, 242 patients underwent left-sided and 252 patients underwent right-sided laparoscopic adrenalectomy. For left side, transperitoneal approach was used in 132 (103 with tumors < 5 cm and 29 with tumors ≥ 5 cm) and retroperitoneal approach in 110 (102 with tumors < 5 cm and 8 with tumors ≥ 5 cm). For right side, transperitoneal approach was used in 139 (121 with tumors < 5 cm and 18 with tumors ≥ 5 cm) and retroperitoneal approach in 113 (102 with tumors < 5 cm and 11 with tumors ≥ 5 cm). Patient characteristics and perioperative outcomes were recorded. For each side, both approaches were compared for tumors < 5 cm and ≥ 5 cm respectively. RESULTS: For left-sided tumors < 5 cm, transperitoneal approach demonstrated shorter operative time, less blood loss and longer time to oral intake. For left-sided tumors ≥ 5 cm, the peri-operative data of both approaches was comparable. For right-sided tumors < 5 cm, transperitoneal approach demonstrated shorter operative time and less blood loss. For right-sided tumors ≥ 5 cm, the peri-operative data was comparable. CONCLUSIONS: Lateral transperitoneal and retroperitoneal approach are both effective for laparoscopic adrenalectomy. Lateral transperitoneal approach is faster with less blood loss for tumors < 5 cm.

Ethanol extract of Patrinia scabiosaefolia induces the death of human renal cell carcinoma 786-O cells via SIRT-1 and mTOR signaling-mediated metabolic disruptions.

Recently, natural plant extracts have shown tremendous potential as novel antitumor drugs. Patrinia scabiosaefolia, a traditional prescription for inflammatory diseases, has been reported to effectively suppress various types of cancers. However, the mechanisms underlying its antitumor properties remain elusive. In the present study, we investigated the antitumor effects of an ethanol extract of Patrinia scabiosaefolia (EPS) on human renal cell carcinoma 786-O cells. After 24 h of incubation with EPS, the cell viability and colony number of 786-O cells were significantly decreased in a concentration-dependent manner as compared to the control group as determined by MTT and colony formation assays, respectively. The necrotic rate and apoptotic rate in the EPS exposure group were significantly higher than these rates noted in the control group as revealed by LDH release assay and Hoechst 33342/ PI double staining, respectively. At the concentration of 1.0 mg/ml, the necrotic and apoptotic rates reached 41.7±6.6 and 7.8±1.4%, respectively (P<0.01). However, the fluorescence intensity of intracellular calcium concentration ([Ca2+]i) was markedly elevated from 0.029±0.0007 to 0.060±0.003 (P<0.001) after the intervention of EPS. Moreover, the fluorescence intensity of intracellular ROS in the EPS exposure group was significantly higher (0.074±0.005) compared to that observed in the control group (0.033±0.001, P<0.001), which was partly attenuated by the specific antioxidant N-acetylcysteine (NAC). Furthermore, our results demonstrated that EPS significantly downregulated the expression of SIRT-1 and obviously induced the dephosphorylation of mTOR. Moreover, combined treatment with the SIRT-1 inhibitor nicotinamide and EPS was able to significantly enhance the induction of necrosis and reduction in cell viability of 786-O cells noted following treatment with EPS alone. In summary, we conclude that EPS induced the death of 786-O cells via SIRT-1 and mTOR signaling-mediated metabolic disruptions, which provide novel insight into the application of natural plant extracts for the treatment of cancers.

Autologous granulation tissue tubes for replacement of urethral defects: An experimental study in male rabbits.

INTRODUCTION: Tubularized urethroplasty is commonly performed in clinical practice using genital skin flaps, bladder mucosa, and buccal mucosa. However, the long-term effects are not satisfying, and donor site morbidities remain a problem. Besides, those grafts are unavailable with malignant conditions of the urinary tract, a history of lichen sclerosis, or oral disease. OBJECTIVE: An autologous granulation tissue tube of any required length and diameter can be produced by implanting foreign objects subcutaneously (Summary Fig.). The current study aimed to investigate to what extent of length this fully autologous tissue could be used for tubularized urethroplasty, satisfying urethral patency and tissue regeneration, in male rabbits. STUDY DESIGN: Twenty-seven New Zealand male rabbits were randomly divided into three groups. Silastic tubes were implanted subcutaneously in Group 1 and Group 2. By 2 weeks the granulation tissue encapsulating the tubes was harvested. In Group 1, pendulous urethral segments of 1 cm were excised, and urethroplasty was performed with the granulation tissue tube in an end-to-end fashion. In Group 2, a pendulous urethral segment of 1.5 cm was replaced with the tissue tube. In Group 3, a pendulous urethral defect of 1 cm was repaired by re-anastomosis as control. Serial urethrograms were performed at 1, 2 and 6 months postoperatively. Meanwhile, the neo-urethra were harvested and analyzed grossly and histologically. RESULTS: The urethrograms showed that all animals in Group 1 maintained a wide urethral caliber. In contrast, animals in Group 2 and Group 3 developed progressive strictures. Histologically, an intact urothelium with one to two cell layers lined the graft by 1 month, which was surrounded by increasing organized smooth muscle in Group 1. By 6 months, the grafts were completely integrated into native urethra. Nevertheless, extensive fibrosis occurred in Group 2 and Group 3. DISCUSSION: The tissue successfully maintained patency and guided urethral regeneration across a distance of 1 cm. As an epithelium-free graft, the tissue showed better results than acellular matrix for tubularized urethroplasty compared with previous studies. Nevertheless, several limitations existed: (1) the urethral defect was created in healthy urethra, which could not fully simulate the clinical situation; (2) as a small animal model, rabbit was less informative for clinical problems; (3) the tissue was inadequate for long segmental urethral replacement. Further study is needed before the procedure is used clinically. CONCLUSION: An autologous granulation tissue tube grown subcutaneously could be successfully used to repair urethral defects of 1 cm in male rabbits.

Eukaryotic Translation Initiation Factor 3b is both a Promising Prognostic Biomarker and a Potential Therapeutic Target for Patients with Clear Cell Renal Cell Carcinoma.

Eukaryotic translation initiation factors (eIFs) constitute a new class of therapeutic cancer targets. EIF3b is the major scaffold protein of eIF3 (the largest core of eIFs). We sought to define the role played by and the mechanism of action of eIF3b in patients with clear cell renal cell carcinoma (ccRCC). We found that high-level eIF3b expression in tumors was not only associated with an aggressive tumor phenotype, but was also independently prognostic for patients with ccRCC. Knockdown of eIF3b impaired the action of the Akt pathway, thus inhibiting cell proliferation by disrupting the cell cycle and triggering apoptosis. Furthermore, the epithelial-to-mesenchymal transition was impaired after eIF3b depletion, via suppression of cell migration and invasion. Additionally, eIF3b knockdown significantly inhibited the growth of subcutaneous xenografts in mice. Together, these data show that eIF3b is both a promising prognostic biomarker and a potential therapeutic target for patients with ccRCC.

Urethral Reconstruction Using Mesothelial Cell-Seeded Autogenous Granulation Tissue Tube: An Experimental Study in Male Rabbits.

Objective. This study was to evaluate the utility of the compound graft for tubularized urethroplasty by seeding mesothelial cells onto autogenous granulation tissue. Methods. Silastic tubes were implanted subcutaneously in 18 male rabbits, of which nine underwent omentum biopsies simultaneously for in vitro expansion of mesothelial cells. The granulation tissue covering the tubes was harvested 2 weeks after operation. Mesothelial cells were seeded onto and cocultured with the tissue for 7 days. A pendulous urethral segment of 1.5 cm was totally excised. Urethroplasty was performed with mesothelial cell-seeded tissue tubes in an end-to-end fashion in nine rabbits and with unseeded grafts in others as controls. Serial urethrograms were performed at 1, 2, and 6 months postoperatively. Meanwhile, the neourethra was harvested and analyzed grossly and histologically. Results. Urethrograms showed cell-seeded grafts maintained wide at each time point, while strictures formation was found in unseeded grafts. Histologically, layers of urothelium surrounded by increasingly organized smooth muscles were observed in seeded grafts. In contrast, myofibroblasts accumulation and extensive scarring occurred in unseeded grafts. Conclusions. Mesothelial cell-seeded granulation tissue tube can be successfully used for tubularized urethroplasty in male rabbits.

Overexpression of reptin in renal cell carcinoma contributes to tumor malignancies and its inhibition triggers senescence of cancer cells.

OBJECTIVES: Reptin is an AAA+ ATPase associated with several complexes involved in chromatin remodeling, transcriptional regulation, DNA damage repair, and telomerase activity. Functional studies have implicated reptin in many cellular processes highly relevant to cancer. In this study, we investigated reptin expression in renal cell carcinoma (RCC) and its biologic functions in RCC cells. MATERIALS AND METHODS: A total of 81 RCC patients were involved in the study. Cancerous and adjacent normal renal tissues were analyzed for reptin expression using immunohistochemistry. Univariate association with survival was evaluated using Kaplan-Meier curves. Gene expression was depleted with specific small interference RNA. Clonogenesis, cellular senescence, and cell cycle distribution were examined by foci formation, ß-galactosidase staining, and flow cytometry, respectively. Cell migration and invasion capability were determined by scratch migration assay and Matrigel invasion assay. RESULTS: Reptin is overexpressed in cancerous tissues compared with tumor adjacent renal tissues. Cytoplasmic expression of reptin positively correlates with the poor differentiation of RCC, and predicts an unfavorable outcome for patients. Depleting reptin expression substantially inhibited clonogenic potential of cancer cells and induced senescence of RCC cells. Moreover, reptin depletion attenuated migration and invasion ability of RCC cells in vitro. CONCLUSIONS: Reptin is overexpressed and aberrantly distributed in RCC. It is required for sustained proliferation of cancer cells by preventing cell growth arrest and senescence. Furthermore, reptin promotes cell migration and invasion, which may contribute to the progression of RCC. Therefore, reptin may prove to be a valuable target for prevention and treatment of renal cell carcinoma.

Berberine inhibits the migration and invasion of T24 bladder cancer cells via reducing the expression of heparanase.

Berberine, a quaternary amine and isoquinoline alkaloid, has been proposed to have antimetastatic effects on many types of tumor cells; however, its exact inhibitory mechanisms with bladder cancer cells remain unclear. We used berberine and siRNA technology to interfere the expression of heparanase in bladder cancer T24 cells, detected the expression of heparanase mRNA and protein by reverse transcription PCR and Western blot respectively, and investigated their effects on the migration and invasion of T24 bladder cancer cells using transwell chamber. Our results showed that both mRNA and protein of heparanase were highly expressed in human bladder cancer T24 cells and markedly downregulated by both heparanase-specific siRNA (hpa-siRNA) and berberine. The tumor cell migration assay indicated that transfection of hpa-siRNA and treatment with berberine both attenuated the migration and invasion of T24 cells. Therefore, berberine inhibits the metastasis and invasion of bladder cancer cell, possibly via blocking the heparanase expression and thus may be used clinically to reduce the recurrence of bladder cancer.

Tubularized urethral replacement using tissue-engineered peritoneum-like tissue in a rabbit model.

INTRODUCTION: This study aims to investigate whether mesothelial cells could function as seed cells to construct tissue-engineered peritoneum-like tissue for urethral reconstruction in a rabbit model. MATERIALS AND METHODS: Bladder acellular matrices were prepared and trimmed to 1.5 × 1 cm. Nine male rabbits underwent omentum biopsy and autologous mesothelial cells were isolated. After in vitro expansion, the cells were seeded onto the matrices and incubated for 7 days. In 18 rabbits, a pendulous urethral segment 1.5 cm long was totally excised and urethroplasty was performed with tubularized matrices seeded with cells in 9 animals and without cells in 9 as controls. Urethrography was performed at 1, 2 and 6 months postoperatively. Meanwhile, the neourethras were harvested and analyzed grossly and histologically. RESULTS: Histological analysis of the cell-seeded grafts revealed a loose collagen matrix covered with a single layer of mesothelim. Serial urethrography indicated a wide urethral caliber without stricture formation in animals implanted with cell-seeded matrices, while all animals of the control group developed stricture. Histological analysis of the implanted cell-seeded matrices demonstrated a normal urethral architecture by 1 month, composed of multilayers of urothelium surrounded by smooth muscle bundles, which became increasingly organized with time. By 6 months, the neourethra could be hardly distinguished from native urethra both grossly and histologically. CONCLUSIONS: Autologous mesothelial cells could be successfully used as seed cells for tubularized urethral reconstruction in male rabbits.

Ureteral reconstruction using autologous tubular grafts for the management of ureteral strictures and defects: an experimental study.

OBJECTIVE: To investigate whether the peritoneal cavity could function as a bioreactor to produce autologous tubular grafts for ureteral reconstruction in beagles. MATERIALS AND METHODS: 8-Fr Silastic tubes were implanted into the peritoneal cavities of 6 female beagles. At 3 weeks, the tubes were harvested and the tubular tissue covering the tubes was gently everted. A segment 3 cm in length of the right mid-ureter, involving two thirds of its diameter, was removed parallel to the ureteral axis, leaving a third of the ureteral wall. A 5-Fr double-J stent was inserted into the ureter through the created defect, and two thirds of the graft were anastomosed to both edges of the ureteral defect. One third of the graft was overlapped with the retained normal ureter and anastomosed to the external surface of the lumens. Thus, the graft was partly encapsulated by the remainder of ureteral wall. The stent was maintained for 6 weeks and removed. Excretory urography was performed at 8 (n = 3) and 12 weeks (n = 3), postoperatively. Meanwhile, the neoureter was harvested and analyzed. The left ureter served as the control and a simple intubated ureterotomy was performed. RESULTS: Histological analysis of the tubular tissue demonstrated transversely arranged myofibroblasts and an outer layer of mesothelium. The tissue was easily everted and transplanted as a ureteral graft. Eight weeks postoperatively, the neoureter demonstrated normal ureteral architecture, composed of multilayers of urothelium surrounded by smooth muscle bundles, which became increasingly organized with time. Excretory urography indicated no stenosis or hydronephrosis. CONCLUSIONS: These results show that autologous tubular tissue grown within the recipients' peritoneal cavity can be used for ureteral reconstruction in the beagle model.

Comparison of the transperitoneal and a semi-open retroperitoneal approach for right-sided laparoscopic donor nephrectomy.

BACKGROUND: To investigate whether the retroperitoneal or transperitoneal approach is preferable for right-sided laparoscopic donor nephrectomy (R-LDN). MATERIAL/METHODS: We retrospectively compared the donor and recipient outcomes of R-LDNs performed with a standard transperitoneal approach (n=21) or a semi-open retroperitoneal approach (n=32). RESULTS: Patient demographics were similar between groups. The semi-open retroperitoneal group had shorter operative time (89.5 min vs. 105 min, p<0.001), shorter WIT (102 s vs. 120 s, p<0.001), and longer renal veins (2.5 cm vs. 2.2 cm, p<0.001). No conversions to open procedures occurred. There were no significant differences in the blood loss, length of hospital stay, or donor complication rate between the 2 groups. All grafts functioned adequately, and there were no significant differences in graft function, first-week hemodialysis, and serum creatinine level at discharge between the 2 groups The recipient complication rate was similar between the 2 groups (9.4% vs. 9.5%, p=0.986). CONCLUSIONS: The semi-open retroperitoneal approach is safe and effective for R-LDN. Further study is required to evaluate long-term graft function.

Peritoneal cavity as bioreactor to grow autologous tubular urethral grafts in a rabbit model.

PURPOSE: To investigate whether peritoneal cavity could function as bioreactor to produce autologous tubular grafts for urethral reconstruction in male rabbits. METHODS: 8Fr silastic tubes were implanted into peritoneal cavities of nine male rabbits. By 2 weeks, tubes were harvested and the tubular tissue covering the tubes was everted. A pendulous urethral segment of 1.5 cm long was totally excised and urethroplasty was performed with the everted tubular tissue in an end-to-end fashion. Another nine male rabbits underwent the same urethral resection and re-anastomosis as controls. Urethrography was performed at 1, 2 and 6 months postoperatively. Meanwhile, the neo-urethra were harvested and analyzed grossly and histologically. RESULTS: Histological analysis of the tubular tissue demonstrated transversely arranged myofibroblasts embedded in homogeneous collagen bundles and an outer layer of mesothelium. The tissue was easily everted and successfully transplanted as a urethral graft. Serial urethrography indicated no stricture or diverticula formation. While all animals of the control group developed stricture. Histological analysis of the neo-urethra demonstrated normal urethral architecture by 1 month, composed of multi-layers of urothelium surrounded by smooth muscle bundles, which became increasingly organized with time. By 6 months, the neo-urethra could be hardly distinguished from native urethra both grossly and histologically. CONCLUSIONS: These results show that the autologous tissue grown within the recipients' peritoneal cavity can be used successfully for tubularized urethral reconstruction in male rabbits.