An endothelialized urothelial cell-seeded tubular graft for urethral replacement.

INTRODUCTION: Many efforts are used to improve surgical techniques and graft materials for urethral reconstruction. We developed an endothelialized tubular structure for urethral reconstruction. METHODS: Two tubular models were created in vitro. Human fibroblasts were cultured for 4 weeks to form fibroblast sheets. Then, endothelial cells (ECs) were seeded on the fibroblast sheets and wrapped around a tubular support to form a cylinder for the endothelialized tubular urethral model (ET). No ECs were added in the standard tubular model (T). After 21 days of maturation, urothelial cells were seeded into the lumen of both models. Constructs were placed under perfusion in a bioreactor for 1 week. At several times, histology and immunohistochemistry were performed on grafted nude mice to evaluate the impact of ECs on vascularization. RESULTS: Both models produced an extracellular matrix, without exogenous material, and developed a pseudostratified urothelium. Seven days after the graft, mouse red blood cells were present only in the outer layers in T model, but in the full thickness of ET model. After 14 days, erythrocytes were present in both models, but in a greater proportion in ET model. At day 28, both models were well-vascularized, with capillary-like structures in the whole thickness of the tubes. CONCLUSION: Incorporating endothelial cells was associated with an earlier vascularization of the grafts, which could decrease the necrosis of the transplanted tissue. As those models can be elaborated with the patient's cells, this tubular urethral graft would be unique in its autologous property.

Prospective study comparing two techniques of renal clamping in laparoscopic partial nephrectomy: impact on perioperative parameters.

PURPOSE: To compare en bloc and artery-only clamping techniques on renal function and perioperative outcomes after laparoscopic partial nephrectomy (LPN). PATIENTS AND METHODS: From March 2003 to December 2008, 205 patients underwent LPN by one surgeon in a single institution. The first 103 LPNs were achieved with artery-only clamping (AO), and the last 102 LPNs were realized under control of the renal hilum (artery and vein [AV] clamping). Renal function was evaluated by creatinine changes, estimation of the glomerular filtration rate (eGFR), and assessment of split renal function using renal mercaptoacetyl triglycine-Lasix scintigraphy. Sixty-two of 205 patients had renal scintigraphy before and after surgery. RESULTS: There was no significant difference between the two groups regarding demographic data and renal mass characteristics. Warm ischemia time (WIT) was higher in the AO group: 30.4 ± 8.2 vs 23.3 minutes ± 10.0 (P<0.0001). The eGFR change was significantly lower in the AV group during the postoperative period: 10.2 mL/min vs 13.7 mL/min (P=0.0472). Operative blood loss, operative time, and complication rate were not statistically different between groups. Average loss of differential function of the operated kidney was 13.6 ± 9.2% for the AO group and 14.3 ± 12.3% for the AV group (P=0.8016). On multivariate analysis, clamping technique was not a predictive factor of renal function reduction. CONCLUSION: AV and AO techniques are associated with similar renal function outcomes in patients who were undergoing LPN. In our series, the AV technique was associated with a lower WIT, an important predictor of decrease in renal function.

Surgical option for the correction of Peyronie's disease: an autologous tissue-engineered endothelialized graft.

INTRODUCTION: Surgical treatment is indicated in severe cases of Peyronie's disease. Incision of the plaque with subsequent graft material implantation is the option of choice. Ideal graft tissue is not yet available. AIM: To evaluate the use of an autologous tissue-engineered endothelialized graft by the self-assembly method, for tunica albuginea (TA) reconstruction in Peyronie's disease. METHODS: Two TA models were created. Human fibroblasts were isolated from a skin biopsy and cultured in vitro until formation of fibroblast sheets. After 4 weeks of maturation, human umbilical vein endothelial cells (HUVEC) were seeded on fibroblasts sheets and wrapped around a tubular support to form a cylinder of about 10 layers. After 21 days of tube maturation, HUVEC were seeded into the lumen of the fibroblast tubes for the endothelialized tunica albuginea (ETA). No HUVEC were seeded into the lumen for the TA model. Both constructs were placed under perfusion in a bioreactor for 1 week. MAIN OUTCOME MEASURES: Histology, immunohistochemistry, and burst pressure were performed to characterize mature tubular graft. Animal manipulations were also performed to demonstrate the impact of endothelial cells in vivo. RESULTS: Histology showed uniform multilayered fibroblasts. Extracellular matrix, produced entirely by fibroblasts, presented a good staining for collagen 1. Some elastin fibers were also present. For the TA model, anti-human von Willebrand antibody revealed the endothelial cells forming capillary-like structures. TA model reached a burst pressure of 584 mm Hg and ETA model obtained a burst pressure of 719 mm Hg. CONCLUSIONS: This tissue-engineered endothelialized tubular graft is structurally similar to normal TA and presents an adequate mechanical resistance. The self-assembly method used and the autologous property of this model could represent an advantage comparatively to other available grafts. Further evaluation including functional testing will be necessary to characterize in vivo implantation and behavior of the graft.

Multivariate analysis of the factors involved in loss of renal differential function after laparoscopic partial nephrectomy: a role for warm ischemia time.

BACKGROUND: Partial nephrectomy (PN) is now the gold standard for the surgical treatment of small renal masses. We evaluated the effect of WIT and other factors on RDF assessed by preoperative and postoperative renal scintigraphy. METHODS: Between 2003 and 2008, 182 consecutive laparoscopic PN (LPN) were performed in an academic centre. Among those, 56 had mercaptoacetyl triglycine (MAG3) lasix renal scintigraphy preoperatively and postoperatively. RESULTS: Medians for age, preoperative estimated glomerular filtration rate and computed tomography scan tumour size were 62 years, 82 mL/min/1.73m(2) and 26 mm, respectively. Median WIT and preoperative RDF were 30 minutes and 50%, respectively. Median loss of RDF after surgery was 14%. Linear regression curves showed that loss in RDF rate was 0.2% per minute when WIT was <30 minutes and 0.7% per minute when WIT was ≥30 minutes. In multivariate analysis, length of WIT and endophytic tumour location were associated with a statistically significant loss of RDF (p < 0.05), but only in the group who experienced >30 minutes of WIT. INTERPRETATION: Our results suggest that the factors associated with loss of RDF are not the same before and after 30 minutes of WIT and that the rate of loss in RDF increases after 30 minutes. Since, the effect of WIT is small up to 30 minutes, we believe that surgery should focus on limiting the resection of normal parenchyma and to ensure negative margins and hemostasis, rather than on premature unclamping.

Massive hemorrhage from spontaneous rupture of a retroperitoneal lymph node in patient with metastatic mixed germ cell tumor.

Spontaneous hemoperitoneum secondary to metastatic foci of testicular germ cell tumor is a rare finding and is usually precipitated by the beginning of chemotherapy treatments. This acute presentation is usually due to the rupture of hepatic or gastrointestinal metastasis. We present the case of a 16-year-old boy who was admitted to the emergency room with acute abdominal pain and unstable vital signs, 10 days after a left orchiectomy for a testicular mixed nonseminomatous tumor. An urgent laparotomy demonstrated a significant peritoneal effusion (3 L) secondary to a ruptured retroperitoneal lymph node. More than 90% of the mass was resected with 3 cm of adherent jejunum. Pathologic findings revealed the mass to be composed of more than 95% of choriocarcinoma. The patient recovered well from the surgery and received standard chemotherapy with good response and no residual disease. Two and a half years after diagnosis, the patient is still in remission.