Urothelial cell culture: stratified urothelial sheet and three-dimensional growth of urothelial structure.
ABSTRACT Urothelial cells line the urinary tract, including the renal pelvis, ureters, bladder, superior urethra, and the central ducts of the prostate. They are highly specialized epithelial cell types possessing unique features, imparting important functional roles in the urinary system. They act as a permeability barrier and protect underlying muscle tissues from the caustic effects of urine while also expanding with bladder filling to adjust urine pressures. The multilayered urothelium is typically structured with differentiated, mature surface cells and less mature basal cells. The basal cell layer contains tissue-specific stem cells able to self-renew for the lifetime of the mammal and also produces a pool of maturing cells for tissue homeostasis. Maintaining regenerative basal cells in a culture facilitates urothelial cell growth in vitro. Additionally, epithelial-mesenchymal communication, epithelial-matrix interactions, and cytokines/growth factors are required to maintain the normal structure and function of mature urothelial cells in vitro and to induce stem cell differentiation into urothelial cells. These cultures are useful to study the biology and physiology of the urinary tract, particularly for the development of cell-based tissue engineering strategies in urology. This chapter describes methods for the isolation of urothelial cells and their maintenance in monolayer culture, and methods for the production of multilayer urothelial cell sheets and three-dimensional cocultures of urothelial and mesenchymal cells.
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ABSTRACT: Urethral stricture is characterized by urethral lumen narrowing due to fibrosis. Urethroplasty of the urethral stricture involves excision of scar, and may be followed by reconstruction of the urethra using split-thickness skin, buccal mucosa, urethral mucosa or, more recently, tissue-engineered grafts. The stricture wound healing process after urethroplasty is known to be mediated by an interaction between keratinocyte and fibroblasts; however, the underlying mechanisms are not studied in detail yet. We investigated the influence of epithelial cell-conditioned medium (ECCM) (obtained from confluent penile skin, buccal mucosa and urethral cell cultures) on the proliferation and migration of stricture fibroblasts using an in vitro scratch assay. ECCM was collected from confluent primary epithelial cell cultures of three different human biopsies (penile skin, buccal mucosa and urethral mucosa), whereas stricture fibroblasts were isolated from human urethral stricture biopsies. The effect of ECCM on stricture fibroblasts' proliferation and migration into the scratch was observed using a standard in vitro scratch assay over a period of 3 days. Four experiments were performed independently using four stricture fibroblasts from four patients and ECCM was collected from 12 different patients' primary cell cultures. ECCM from primary epithelial cells cultures obtained from penile skin, buccal mucosa and urethra inhibited stricture fibroblasts' proliferation and migration in the in vitro scratch assay. These results demonstrate the ability of ECCM to inhibit the proliferation and migration of stricture fibroblasts and present it as an effective adjunct in urethroplasty, which may influence stricture wound healing and inhibit the recurrence of stricture.Indian Journal of Urology 04/2015; DOI:10.4103/0970-1591.152809
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ABSTRACT: Over the last few decades, both synthetic and natural materials have been utilized to develop bladder substitutes. Most attempts have not been successful because of mechanical, structural, functional, or biocompatibility problems. Bladder acellular matrix (BAM) is obtained by removing cellular components from donor bladders, leaving a tissue matrix consisting of collagen, elastin, fibronectin, glycosaminoglycans (GAGs), proteoglycans, and growth factors. Multiple BAM-based studies now suggest that tissue engineering techniques may provide efficacious alternatives to current methods of bladder augmentation. Efforts to optimize BAM-based scaffolds are ongoing and would be greatly assisted by feasible means of improving scaffold properties and interaction with cells and tissues. Future applications of BAM will likely include cell-seeded grafts with the eventual hope of producing "off the shelf" replacement materials for bladder augmentation.Tissue Engineering Part B Reviews 07/2013; DOI:10.1089/ten.TEB.2013.0103 · 4.64 Impact Factor
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ABSTRACT: BACKGROUND: We investigated the feasibility of urethral reconstruction using stretched electrospun silk fibroin matrices. MATERIALS AND METHODS: A novel electrospun silk fibroin matrix was prepared. The structure of the material was assessed by scanning electron microscopy and a porosity test. Canine urothelial cells were isolated, expanded, and seeded onto the material for 1 wk to obtain a tissue-engineered graft. The tissue-engineered graft was assessed using hematoxylin and eosin staining and scanning electron microscopy. A dorsal urethral mucosal defect was created in nine female beagle dogs. In the experimental group, tissue-engineered mucosa was used to repair urethra mucosa defects in six dogs. No substitute was used in the three dogs of the control group. Retrograde urethrography was performed at 1, 2, and 6 mo after grafting. The urethral grafts were analyzed grossly and histologically. RESULTS: Scanning electron microscope and a porosity test revealed that the material had a three-dimensional porous structure. Urothelial cells grew on the material and showed good biocompatibility with the stretched silk fibroin matrices. Canines implanted with tissue-engineered mucosa voided without difficulty. Retrograde urethrography revealed no signs of stricture. Histologic staining showed gradual epithelial cell development and stratified epithelial layers at 1, 2, and 6 mo. The canines in the control group showed difficulty in voiding. Retrograde urethrography showed urethra stricture. Histologic staining showed that no or only one layer of epithelial cells developed. A severe inflammatory reaction was also observed in the control group. CONCLUSIONS: Stretched electrospun silk fibroin matrices have good biocompatibility with urothelial cells, which could prove to be a potential material for use in urethra reconstruction.Journal of Surgical Research 04/2013; 184(2). DOI:10.1016/j.jss.2013.04.016 · 2.12 Impact Factor