208 Surgical Option for Urethral Reconstruction: An Autologous Tissue-Engineered Tubular Graft (original) (raw)
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Reconstruction of Vascular and Urologic Tubular Grafts by Tissue Engineering
Processes
Tissue engineering is one of the most promising scientific breakthroughs of the late 20th century. Its objective is to produce in vitro tissues or organs to repair and replace damaged ones using various techniques, biomaterials, and cells. Tissue engineering emerged to substitute the use of native autologous tissues, whose quantities are sometimes insufficient to correct the most severe pathologies. Indeed, the patient’s health status, regulations, or fibrotic scars at the site of the initial biopsy limit their availability, especially to treat recurrence. This new technology relies on the use of biomaterials to create scaffolds on which the patient’s cells can be seeded. This review focuses on the reconstruction, by tissue engineering, of two types of tissue with tubular structures: vascular and urological grafts. The emphasis is on self-assembly methods which allow the production of tissue/organ substitute without the use of exogenous material, with the patient’s cells producing t...
Transplantation proceedings
Tissue-engineering methods using synthetic biodegradable scaffolds seeded with cells have potential to induce regeneration to a functional bladder wall. The aim of the study was to induce in vivo urothelial growth on implanted scaffolds previously seeded with stromal cells as compared with matrices implanted without cells for rat cystoplasty augmentation. 3T3 mouse fibroblasts were multiplied up to total of 10(8) cells. Cells were grown on Dulbecco's modified essential medium supplemented with 10% of fetal bovine serum and antibiotics in CO(2) chambers. Cells were seeded on biodegradable polyglycolic acid (PGA) scaffolds in eight rats: four bladders were augmented with cell-seeded grafts and the other four with acellular scaffolds. Rats were sacrificed after 4 months in preparation for hematoxylin and eosin staining. One death in the acellular cystoplasty group was observed after 3 weeks. No epithelial layer was observed in the central part of the acellular graft. The cell-seede...
Scientific Reports
Urogenital reconstructive surgery can be impeded by lack of tissue. Further developments within the discipline of tissue engineering may be part of a solution to improve clinical outcomes. In this study, we aimed to design an accessible and easily assembled tubular graft with autologous tissue, which could be constructed and implanted as a single-staged surgical procedure within the premises of an ordinary operating room. The ultimate goals would be to optimize current treatment-options for long-term urinary diversion. Therefore, we evaluated the optimal composition of a collagen-based scaffold with urothelial micrografts in vitro, and followingly implanted the construct in vivo as a bladder conduit. The scaffold was evaluated in relation to cell regeneration, permeability, and biomechanical properties. After establishing an optimized scaffold in vitro, consisting of high-density collagen with submerged autologous micrografts and reinforced with a mesh and stent, the construct was s...
Artificial Organs, 2008
Abstract: Acquired or congenital abnormalities may lead to urethral damage or loss, often requiring surgical reconstruction. Urethrocutaneous fistula and strictures are common complications, due to inadequate blood supply. Thus, adequate blood supply is a key factor for successful urethral tissue reconstruction. In this study, urethral grafts were prepared by seeding rabbit bladder urothelial cells (UCs) modified with human vascular endothelial growth factor (VEGF165) gene in the decellularized artery matrix. A retroviral pMSCV-VEGF165-GFP vector was cloned by insertion of VEGF open reading frame into the vector pMSCV-GFP (murine stem cell virus [MSCV]; green fluorescent protein [GFP]). Retrovirus was generated using package cell line 293T. Rabbit UCs were expanded ex vivo and modified with either MSCV-VEGF165-GFP or control MSCV-GFP retrovirus. Transduction efficiency was analyzed by fluorescence-activated cell sorting. The expression of VEGF165 was examined by immunofluorescence, reverse transcript-polymerase chain reaction, Western blot, and enzyme-linked immunosorbent assay (ELISA). Decellularized rabbit artery matrix was seeded with genetically modified UCs and was subsequently cultured for 1 week prior to subcutaneous implantation into nude mice. Four weeks after implantation, the implants were harvested and analyzed by fluorescence microscopy, and by histologic and immunohistochemical staining. Ex vivo transduction efficiency of UCs was greater than 50% when concentrated retrovirus was used. The modified cells expressed both VEGF and GFP protein. Furthermore, the VEGF-modified UCs secreted VEGF in a time-dependent manner. Scanning electron microscopy and histochemical analysis of cross sections of the cultured urethral grafts showed that the seeded cells were attached and proliferated on the luminal surface of the decellularized artery matrix. In the subcutaneously implanted vessels, VEGF-modified cells significantly enhanced neovascularization and the formation of a urethral layer compared to GFP-modified cells. These results indicate that VEGF gene therapy may be a suitable approach to increase the blood supply in tissue engineering for treatment of urethral damage or loss.
Minced Urothelium to Create Epithelialized Subcutaneous Conduits
The Journal of Urology, 2010
We used in vivo cell expansion to create 3-dimensional subcutaneous conduits lined with an inner layer of autologous urothelial mucosa. Materials and Methods: Laparotomy and excision of a fifth of the bladder were done in 5 female Yorkshire pigs (Parsons Farm, Westhampton, Massachusetts) under general anesthesia. After mechanical removal of the detrusor muscle the bladder mucosa was minced to obtain 0.2 ϫ 0.8 ϫ 0.8 mm particles, which were attached to the outer surface of latex tubes using a thin layer of fibrin glue. Seven to 10 tubes were placed in the abdominal wall subcutaneous tissue in each original donor pig with tubes lacking particles serving as controls. Biopsy was done 1 to 4 weeks after transplantation for histological evaluation. Results: One week after transplantation particles were still present in the granulation tissue. At 2 weeks the epithelium was differentiated with transitional uroepithelium facing the lumen, ie toward the tube. No epithelium was detected around control tubes. Conclusions: After autologous transplantation of bladder mucosal particles organized in 3-dimensional fashion in pig subcutaneous tissue the transplanted cells proliferated, migrated and reorganized to form a continuous epithelial lining facing the lumen. This novel approach to urothelial transplantation may allow successful formation of a conduit to the bladder or of a neourethra.
Tissue Engineering of Urinary Bladder and Urethra: Advances from Bench to Patients
The Scientific World Journal, 2013
Urinary tract is subjected to many varieties of pathologies since birth including congenital anomalies, trauma, inflammatory lesions, and malignancy. These diseases necessitate the replacement of involved organs and tissues. Shortage of organ donation, problems of immunosuppression, and complications associated with the use of nonnative tissues have urged clinicians and scientists to investigate new therapies, namely, tissue engineering. Tissue engineering follows principles of cell transplantation, materials science, and engineering. Epithelial and muscle cells can be harvested and used for reconstruction of the engineered grafts. These cells must be delivered in a well-organized and differentiated condition because water-seal epithelium and well-oriented muscle layer are needed for proper function of the substitute tissues. Synthetic or natural scaffolds have been used for engineering lower urinary tract. Harnessing autologous cells to produce their own matrix and form scaffolds is a new strategy for engineering bladder and urethra. This self-assembly technique avoids the biosafety and immunological reactions related to the use of biodegradable scaffolds. Autologous equivalents have already been produced for pigs (bladder) and human (urethra and bladder). The purpose of this paper is to present a review for the existing methods of engineering bladder and urethra and to point toward perspectives for their replacement.
Engineered human organ-specific urethra as a functional substitute
Scientific Reports
Urologic patients may be affected by pathologies requiring surgical reconstruction to re-establish a normal function. The lack of autologous tissues to reconstruct the urethra led clinicians toward new solutions, such as tissue engineering. Tridimensional tissues were produced and characterized from a clinical perspective. The balance was optimized between increasing the mechanical resistance of urethral-engineered tissue and preserving the urothelium’s barrier function, essential to avoid urine extravasation and subsequent inflammation and fibrosis. The substitutes produced using a mix of vesical (VF) and dermal fibroblasts (DF) in either 90%:10% or 80%:20% showed mechanical resistance values comparable to human native bladder tissue while maintaining functionality. The presence of mature urothelium markers such as uroplakins and tight junctions were documented. All substitutes showed similar histological features except for the noticeable decrease in polysaccharide globules for th...
Frontiers in Pediatrics
Introduction: Tissue engineering is a potential source of urethral substitutes to treat severe urethral defects. Our aim was to create tissue-engineered urethras by harvesting autologous cells obtained by bladder washes and then using these cells to create a neourethra in a chronic large urethral defect in a rabbit model.Methods: A large urethral defect was first created in male New Zealand rabbits by resecting an elliptic defect (70 mm2) in the ventral penile urethra and then letting it settle down as a chronic defect for 5–6 weeks. Urothelial cells were harvested noninvasively by washing the bladder with saline and isolating urothelial cells. Neourethras were created by seeding urothelial cells on a commercially available decellularized intestinal submucosa matrix (Biodesign® Cook-Biotech®). Twenty-two rabbits were divided into three groups. Group-A (n = 2) is a control group (urethral defect unrepaired). Group-B (n = 10) and group-C (n = 10) underwent on-lay urethroplasty, with u...
Tissue Engineering in Urology- Progress and Prospects - A Review Article
Open Access Journal of Urology & Nephrology
Regenerative medicine is a new branch of medicine based on tissue engineering technology. This field of science has many things to offer in reconstructive urology where native organ is non-functional, and no substitute is available. Despite the initial promising results, it has not become a reality in the true sense. There are numerous obstacles that are slowing down the process of regenerative medicine. The progress shown in stem cell biotechnology and material science provides new vistas to translate experimental methods clinical reality. Tissue engineering encompasses a multidisciplinary approach with the main aim of development of biological substitutes designed to restore and maintain normal function in diseased or injured organs. This review is done to ascertain its current status and the progress that has been made in regenerative medicine in the reconstruction of various Genito-urinary organs.