De Coppi et al. [74] set up a model of bladder acute necrotizing injury to test the efficacy of adult rat bone marrow mesenchymal stem cell (MSC) vs. fetal rat amniotic fluid MSC transplantation for the treatment of the impaired detrusor muscle contractility that develops when a cryoinjury is applied to the bladder wall. Impaired detrusor muscle contractility is part of the wound-healing process, which is characterized by SMC depletion, followed by SMC hyperplasia and tissue remodeling in the surviving bladder. At 30 days after transplantation, only a few fetal or adult MSCs gave rise to enteric or vascular SMCs, whereas most MSCs appeared incapable of specific differentiation. In vitro coculture experiments using SMCs with fetal or adult MSCs selectively labeled with distinct fluorochromes showed the presence of hybrid cells, suggesting that some MSCs can undergo cell fusion. Surprisingly, the major effect of rat bone marrow or amniotic fluid MSC transplantation seemed to be preventing the cryoinjury-induced hypertrophy of surviving SMCs. In this model, stem cell transplantation had a limited effect on SMC regeneration. Instead, it regulated post-injury bladder remodeling, possibly via a paracrine mechanism.

The potential risk of using diseased tissue as a source of cells for tissue engineering necessitates the investigation of other possible cell sources. One promising source is the bone marrow, which is a known source of stem cells for hematopoietic and mesenchymal lineages. Bone marrow-derived MSCs mobilize from the marrow in response to tissue damage and contribute to the normal regeneration process, and MSCs have been shown to localize in urinary bladders undergoing tissue regeneration after acellular bladder augmentation in rats [79]. Shukla et al. [67] characterized bone marrow-derived MSCs from pigs and demonstrated their ability to differentiate into SMCs and utility for autologous augmentation cystoplasty. MSCs were isolated from pigs and analyzed for common markers of MSCs by flow cytometry, and SMC differentiation was assessed by immunoblotting. MSCs were isolated, genetically labeled, expanded in vitro, seeded onto SIS, and used for autologous bladder augmentation. Porcine MSCs are morphologically and immunophenotypically similar to human MSCs. Culturing MSCs at low density enhances their proliferation rates, whereas maintenance at confluence consistently induces differentiation into mature SMCs. Labeled MSCs grew on SIS for 1 week in vitro and survived a 2-week implantation as an autologous bladder augment in vivo. Some SMC label-positive cells with typical SMC morphology were detected; however, most cells were SMC label negative. Notably, many cells with a urothelial morphology stained positively for SMC markers. Porcine MSCs have properties similar to those of MSCs from other species and consistently undergo differentiation into mature SMCs in vitro under specific culture conditions. The addition of MSCs to SIS may enhance tissue regeneration in augmentation cystoplasty; however, they may not be significantly incorporated into smooth muscle bundles.

Anumanthan et al. [76] reported directed differentiation of bone marrow-derived MSCs into bladder urothelium for use as a source of pluripotent or multipotent progenitor cells. The epithelium was separated from the mesenchymal shells of embryonic day 14 rat bladders. MSCs were isolated from mouse femoral and tibial bone marrow, and heterospecific recombinant xenografts were created by combining embryonic rat bladder mesenchymal shells with the MSCs and grafting them into the renal subcapsular space of athymic nude mice. Grafts were harvested at time points of up to 42 days and stained for urothelial and stromal differentiation. Histological examination of xenografts comprising mouse MSCs and rat embryonic rat bladder mesenchyma yielded mature bladder structures with normal microscopic architecture and expression of proteins confirming functional characteristics. Specifically, the induced urothelium expressed uroplakin, a marker of urothelial differentiation. These differentiated bladder structures also showed appropriate alpha-smooth muscle actin staining. Finally, Hoechst staining of the xenografts revealed a nuclear architecture consistent with a mouse mesenchymal stem cell origin in the urothelium, supporting the differentiation of these cells. In the appropriate signaling environment, bone marrow-derived MSCs can undergo directed differentiation toward endodermal-derived urothelium and develop into mature bladder tissue within a tissue recombination model. This model serves as an important tool for the study of bladder development with a long-term goal of cell replacement therapy applications.

In 1981, embryonic stem (ES) cells were isolated from mice for the first time [80]. This major breakthrough revolutionized the field of developmental biology. ES cells are capable of prolonged self-renewal and differentiation, providing a tool to investigate the molecular mechanisms occurring during differentiation from the embryo to adult. ES cells are considered to be pluripotent and can differentiate into almost all cell types that arise from the three embryonic germ layers [81]. In vitro, these cells can differentiate into multiple embryonic and adult cell types but rarely cells of endodermal lineage [82]. In contrast, differentiation of ES cells in an in vivo environment shows their full developmental potential. Whether stem and/or progenitor cells exist within the bladder is unknown, but hypothetically, they should exist. Identification of stem cells within the vast population of cells in the bladder would be challenging, especially without bladder-specific stem/progenitor cell markers. Oottamasathien et al. [77] determined the specific mesenchymal to ES cell ratios necessary to promote organ-specific differentiation while completely suppressing teratomatous growth. The embryonic mesenchyme is well established as an inductive tissue that dictates organ-specific programming of epithelial tissues, and this study showed that embryonic bladder mesenchyme can also drive ES cell differentiation toward endodermal-derived urothelium. These approaches allow us to capture specific stages of stem cell differentiation and better define stem cell hierarchies.

Urine-derived stem cells (USCs) consistently expressed MSC/pericyte markers and some key cell surface markers but no hematopoietic stem cell markers (except for MHC-1), endothelial markers (CD31), or human leukocyte antigen (locus) DR (HLA-DR) [83]. Compared to other MSCs, USCs have several advantages: (1) they can be collected using a simple, low-cost, safe, noninvasive procedure; (2) they display telomerase activity, and, thus, they are able to generate more cells; and (3) they can efficiently differentiate into SMCs, UCs, and endothelial cells. Chun and Kim et al. [70] investigated whether cells isolated from the upper urinary tract (UTCs) possess stem cell characteristics and could be used as an alternative cell source for patients with bladder cancer. Current tissue engineering approaches for urologic tissue regeneration require invasive tissue biopsies to obtain autologous cells, and these procedures are associated with various potential complications, such as donor site morbidity. Recently, cells isolated from voided urine (VUCs) have been proposed as an alternative cell source for urologic tissue engineering. However, VUCs should not be used in patients with bladder cancer, because the voided urine sample could contain malignant cells. In the study, urine samples were collected from the upper urinary tract of four male patients with bladder cancer using a ureteral catheter. The samples were centrifuged, and the cell pellets were plated for primary culture. The cells were analyzed for the number of colony-forming units, proliferation rate, cytogenetics, stem cell characteristics, and tumorigenicity, and the results were compared to those of VUCs collected from three healthy men. The UTCs were able to form colonies, had a greater proliferation rate than the VUCs, and had a normal karyotype. The UTCs possessed stem cell characteristics (expression of CD44+, CD73+, CD90+, CD105+, and SSEA4+) and expressed several markers of the urothelial, smooth muscle, and endothelial cell lineages. The UTCs did not form teratomas when implanted into the subcapsular space of a mouse kidney. Since the UTCs possessed stem cell characteristics, they could potentially be an alternative cell source for urologic tissue regeneration in patients with bladder cancer.

Induced pluripotent stem cells (iPSCs) are naturally programmed to divide continuously and remain undifferentiated. Although these cells can give rise to ectodermal, mesodermal, or endodermal cell lineages, a significant risk of teratoma exists. Any undifferentiated iPSCs placed in the body might continue to divide in an uncontrolled manner, forming tumors. In addition, it takes a long time (4 months) to derive and characterize iPSCs from an individual. Furthermore, the low efficiency of differentiation, genetic abnormalities, and high cost prohibit their clinical applicability. Despite this, a few studies of ESCs or iPSCs for bladder tissue engineering have been reported. Frimberger et al. [76] reported that human embryoid body-derived stem cells showed improved migration in the presence of mature human bladder SMCs and urothelial cells. In addition, Moad et al. [77] reported the generation of human iPSCs derived from normal and aging human urinary tract tissue. These iPSCs underwent bladder differentiation more efficiently than skin-derived iPSCs, as shown by the expression of urothelial-specific markers (uroplakins, claudins, and cytokeratin) and stromal smooth muscle markers (alpha-smooth muscle actin, calponin, and desmin), indicating the importance of organ-specific iPSCs for tissue-specific studies. Immobilized cell lines are not suitable for bladder regeneration due to safety concerns. Therefore, multipotent adult stem cells are currently used in bladder repair and reconstruction. Of particular interest is the paper published by Xue et al. [84], in which they describe a practical method to generate human iPSCs from USCs under feeder-free, virus-free, serum-free conditions without the c-MYC oncogene. The authors showed that this approach could be applied in a large population with different genetic backgrounds. USCs are easily accessible and exhibit high reprogramming efficiency, offering several advantages over other cell types used for iPSC generation. Using the approach described in this study, the authors generated 93 iPSC lines from 20 donors with diverse genetic backgrounds. The nonviral iPSC bank containing these cell lines is a valuable resource for iPSC research, facilitating future applications of human iPSCs. Table 8.1 shows a comparison of the various stem cell types used in bladder repair studies.

Jayo et al. compared the in situ cellular responses to two biopolymer implants, a polylactic-co-glycolic acid-based biodegradable mesh scaffold with autologous urothelial cells and SMCs (construct) and a PLGA-based biodegradable mesh scaffold without cells (scaffold), in a canine model of augmentation cystoplasty [87]. Healing events were correlated with urodynamic assessments. Construct implants regenerated baseline urodynamics as early as 4 months after implantation. In contrast, following scaffold implantation, urodynamics failed to return to baseline by study termination (9 months). The functional differences elicited by the construct and scaffold implants were correlated with structural differences in the neo-tissues. The construct stroma had greater vascularization, with gently folded, interwoven connective tissue elements. Conversely, the scaffold stroma was dense, with haphazardly organized connective tissue. The urothelium was regenerated in response to both construct and scaffold implantation. However, only the construct urothelium had normal stroma, well-developed detrusor, and abundant alpha-smooth muscle actin cell staining at early time points, leading to a structurally and functionally complete bladder wall at 9 months. They concluded that early cellular and stromal events distinguished the healing processes that led to bladder wall regeneration or repair. Construct implants containing cells elicited early healing processes that culminated with the regeneration of complete mucosal and muscular components. In contrast, the response to scaffold implantation was consistent with reparative healing, i.e., mucosal growth, but incomplete tissue layer development. These independent studies demonstrate that cells are necessary to improve bladder function when a large bladder tissue implant is required.

The utility of allogenic bladder submucosa seeded with cells as a biomaterial for bladder augmentation was investigated by Yoo et al. in 1998 [62]. Partial cystectomies were performed in ten beagle dogs. Both urothelial and SMCs were harvested from five animals and expanded separately. Allogenic bladder submucosa obtained from sacrificed dogs was seeded with muscle cells on one side and urothelial cells on the opposite side. All beagles underwent cruciate cystotomies on the bladder dome. Augmentation cystoplasty was performed with the cell-seeded allogenic bladder submucosa in five animals and unseeded allogenic bladder submucosa in five animals. The augmented bladders were retrieved 2 and 3 months after augmentation. Bladders augmented with the cell-seeded allogenic bladder submucosa showed a 99% increase in capacity compared to bladders augmented with the cell-free allogenic bladder submucosa, which showed only a 30% increase in capacity. All dogs showed normal bladder compliance, as evidenced by urodynamic studies. Histologically, all retrieved bladders contained a normal cellular organization consisting of a urothelial-lined lumen surrounded by submucosal tissue and smooth muscle. Immunocytochemical analyses confirmed the urothelial and muscle cell phenotypes and showed the presence of nerve fibers. In summary, these matrices can function as vehicles for partial bladder regeneration, and no relevant antigenicity is evident.

It has been known for decades that the bladder can regenerate extensively over free grafts, as the urothelium has a high reparative capacity [88]. In their study, de Boer et al. investigated the spatiotemporal changes in the RNA and protein expression of growth factors and their receptors by in situ hybridization and immunocytochemistry during regeneration after acute injury of mouse urothelium. These expression data were well correlated with the changes in cell morphology and proliferation. Except for enhanced muscular transforming growth factor-beta 1 (TGF-beta 1) and TGF-beta type 2 receptor expression, the changes in the expression patterns of growth factors or receptors were confined to the urothelium. Increased mucosal RNA expression of insulin-like growth factor-2 (IGF-2) and particularly type 1 IGF receptor, as well as fibroblast growth factor-1 (FGF-1) but not FGF-2, coincided with reepithelialization and urothelial proliferation. High levels of urothelial TGF-beta 1 RNA and protein expression were associated with reepithelialization and differentiation. In addition, TGF-beta type 2 receptor protein expression was enhanced in the urothelium. Platelet-derived growth factor-A (PDGF-A) RNA was constitutively expressed in the mucosa, but expression decreased in the reepithelialization phase. These data are consistent with the notion that urothelial regeneration can be achieved through paracrine or autocrine mechanisms via urothelium-derived growth factors. The observation of analogous growth factor RNA expression patterns in regenerating skin epidermis suggests a more general growth factor-regulated mechanism for epithelial regeneration.

Bladder muscle tissue is less likely to regenerate normally. Both urothelial and muscle ingrowth are believed to be initiated from the edges of the normal bladder toward the region of the graft [89]. Regeneration of smooth muscle appears to take place within the fibrous tissue characteristically found when biodegradable collagen/Vicryl prosthesis is used to repair full-thickness defects in the rabbit urinary bladder. The question of whether the central smooth muscle was generated via myoblastic differentiation within the fibrous tissue or arose from healthy preexisting detrusor muscle was addressed by serial sectioning and specific staining. Only in situ transmutation, or differentiation, explains the observed morphology, and the results strongly suggest that the central smooth muscle was regenerated from within the repair area.

However, contracture or resorption of the graft is usually evident. The inflammatory response to the matrix may contribute to resorption of the free graft. It was hypothesized that building 3-D constructs in vitro prior to implantation might facilitate the eventual terminal differentiation of the cells after implantation while minimizing the inflammatory response toward the matrix, thus avoiding graft contracture and shrinkage. A study in dogs demonstrated a major difference between matrices with autologous cells (tissue-engineered matrices) and those without cells [62]. Matrices implanted with cells retained most of their implanted diameter, whereas matrices implanted without cells showed graft contraction and shrinkage. The histomorphology demonstrated a marked paucity of muscle cells and a more aggressive inflammatory reaction in the matrices implanted without cells.

To better address the functional parameters of tissue-engineered bladders, a canine animal model was designed that required a subtotal cystectomy and subsequent replacement with a tissue-engineered organ [90]. Cystectomy-only and non-seeded controls maintained average capacities of 22% and 46% of the preoperative values, respectively. In contrast, an average bladder capacity of 95% of the original precystectomy volume was achieved in the cell-seeded tissue-engineered bladder replacements. These findings were confirmed radiographically. Histologically, the non-seeded scaffold bladders presented a pattern of normal urothelial cells with a thickened fibrotic submucosa and a thin layer of muscle fibers. The retrieved tissue-engineered bladders showed a normal cellular organization, consisting of a trilayer of urothelium, submucosa, and muscle. These studies, performed with PGA-based scaffolds, have been repeated by other investigators, and similar results in long-term studies of large numbers of animals have been reported [85, 87]. Jayo et al. [85] evaluated bladder regeneration following 80% cystectomy and augmentation using a synthetic biopolymer with autologous urothelial and SMCs (autologous neo-bladder augmentation construct [construct]) or autotransplantation of native bladder (reimplanted native urinary bladder [reimplant]) in canines. Voiding function, urodynamic assessment, and neo-organ capacity-to-body-weight ratio (C/BW) were assessed longitudinally for 24 months following trigone-sparing augmentation cystoplasty in juvenile canines. Within 30 days postimplantation, hematology and urinalysis returned to baseline. Both the constructs and reimplants yielded neo-organs with statistically equivalent urodynamics and histology. Linear regression analysis of C/BW showed that the constructs regained baseline slope and continued to adapt with animal growth. Constructs and reimplants regained and maintained native bladder histology by 3 months, capacity at 3–6 months, and compliance by 12–24 months. Furthermore, the construct C/BW demonstrated the ability of the regenerated bladder to respond to growth regulation. However, not all scaffolds perform well when used to replace a large portion of the bladder. In a study using SIS for subtotal bladder replacement in dogs, both the unseeded and cell-seeded experimental groups showed graft shrinkage and poor results [91]. In the study, 22 male dogs had a 90% partial cystectomy and were divided into three groups. At 1 month after cystectomy, dogs in the unseeded (n = 6) and seeded (n = 6) groups received a bladder augmentation with a corresponding SIS graft. The dogs in the surgical control group (n = 10) received no further surgery. All dogs were evaluated before and after surgery with blood chemistry, urine culture, intravenous urography, cystogram, and cystometrogram. After surgery (at 1, 5, and 9 months), the bladders were examined by routine histology and immunohistochemistry. All 22 dogs survived the subtotal cystectomy, and 18 survived to the end of their intended survival period. One dog in the seeded group died 1 month after augmentation due to a bladder perforation caused by a large piece of incompletely absorbed SIS. Three other dogs (two in the unseeded group and one in the seeded group) died within 2 months after augmentation due to bladder obstruction by stones. Unseeded and seeded SIS grafts showed moderate to heavy adhesion and graft shrinkage, and some had bone and calcification at the graft site. In both groups, histology showed limited bladder regeneration. Interestingly, dogs in the control group at 1 month after cystectomy (when the seeded and unseeded groups received their augmentations) had severely shrunken bladders and histologically showed severe inflammation, fibroblast infiltration, and muscle hypertrophy. These results verify the subtotal cystectomy model. The use of seeded or unseeded SIS in a subtotal cystectomy model does not yield the same quality and quantity of bladder regeneration observed in the 40% noninflammatory cystectomy model. This study provides important insights into the process of regeneration in a severely damaged bladder. These results led us to reevaluate the critical elements required for complete bladder replacement using tissue engineering.

The type of scaffold used is critical for the success of tissue engineering-based bladder replacement. The use of bioreactors, wherein mechanical stimulation is initiated at organ production, has also been proposed as an important parameter for success [92, 93]. Farhat and Yegar [92] reported that mechanical stimulation may have a role in urinary bladder tissue engineering. Currently, tissue engineering of the urinary bladder relies on biocompatible scaffolds that deliver biological and physical functionality with negligible immunogenic or tumorigenic risks, and recent research suggests that autologous cells propagated in culture and seeded on scaffolds prior to implantation improve clinical outcomes. In addition, as normal urinary bladder development in utero requires regular filling and emptying, current research suggests that bladders constructed in vitro may also benefit from regular mechanical stimulation. Such stimulation appears to induce favorable cellular changes, proliferation, and the production of structurally suitable extracellular matrix (ECM) components that are essential for the normal function of hollow dynamic organs. To mimic in vivo urinary bladder dynamics, tissue bioreactors that imitate the filling and emptying of a normal bladder have been devised. A “urinary bladder tissue bioreactor” that is able to recapitulate these dynamics while providing a cellular environment that facilitates the normal cell-cell and cell-matrix interactions may be necessary to successfully engineer bladder tissue. Validation of a urinary bladder tissue bioreactor that permits careful control of physiological conditions will generate broad interest from researchers in urinary bladder physiology and tissue engineering. A similar study was conducted by Bouhout et al. [86], showing a bladder substitute that was reconstructed in a physiological pressure environment. Bladder reconstruction by enterocystoplasty or with bioengineered substitutes is still associated with complications, which led us to develop an autologous vesical equivalent (VE). This model has already proven its structural conformity. The current challenge is to reconstruct our model in a more physiological environment, with the use of a bioreactor that mimics the dynamics of bladder filling and emptying, to acquire the proper physiological properties. In our model, fibroblasts and urothelial cells were evolved in a 3-D culture to obtain a reconstructed VE. This was then cultured in our bioreactor, which delivers a cyclic pressure increase up to 15 cm H₂O, followed by a rapid decrease, to achieve a dynamically cultured VE (dcVE). The dcVE was characterized by histology and immunofluorescence and compared to the characteristics of statically cultured VE. Mechanical resistance was evaluated by uniaxial tensile tests, and permeability was measured with 14C-urea. Compared to our static model, the dynamic model led to a urothelium profile similar to that of native bladder. Permeability analysis showed a profile comparable to that of native bladder, coinciding with the basal cell organization in the dcVE, and appropriate resistance for suturing and handling was also shown. This new alternative method offers a promising avenue for regenerative medicine. It is distinguished by its autologous character and efficiency as a urea barrier. These properties could significantly reduce inflammation, necrosis, and possibly rejection.

Clinical trials of engineered bladder tissue for cystoplasty reconstruction began in 1998. The first was a small pilot study of seven patients using either a cell-seeded collagen scaffold (with or without omentum coverage) or a combined PGA-collagen cell-seeded scaffold with omental coverage. The patients who underwent reconstruction with the engineered bladder tissue created with the PGA-collagen cell-seeded scaffolds with omental coverage showed increased compliance, decreased end-filling pressure, increased capacity, and longer dry periods over time [12]. In this study, the outcomes were measured by serial urodynamics, cystograms, ultrasounds, bladder biopsies, and serum analyses, and the average follow-up was 46 months (range, 22–61 months). Postoperatively, the mean bladder leak point pressure decreases at capacity, and the greatest increase in volume and compliance was observed in the composite engineered bladders with an omental wrap (56%, 1.58-fold and 2.79-fold, respectively). Bowel function returned promptly after surgery. No metabolic consequences were noted, urinary calculi did not form, mucus production was normal, and renal function was preserved. The engineered bladder biopsies showed an adequate structural architecture and phenotype. Based on these results, engineered bladder tissues created with autologous cells seeded on collagen-polyglycolic acid scaffolds and wrapped in omentum after implantation can be used in patients who require cystoplasty. Although these results are promising since they show that engineered tissues can be implanted safely, it is just a start in terms of accomplishing the goal of engineering fully functional bladders. This was a limited clinical experience, and the technology is not yet ready for wide dissemination; further experimental and clinical studies are required, and phase 2 studies have been completed.

From the aforementioned and the urethral studies, it is evident that the use of cell-seeded matrices is superior to non-seeded matrices for the creation of engineered bladder tissues. Although advances have been made in bladder tissue engineering, many challenges remain. Much of the current research is aimed at the development of biologically active, “smart” biomaterials that may improve tissue regeneration. Similar engineering techniques are now being used in patients with bladder cancer who are having engineered urinary conduits implanted after cystectomy [94]. Muscle-invasive and recurrent non-muscle-invasive bladder cancers have been traditionally treated with a radical cystectomy and urinary diversion. The urinary diversion is generally accomplished through the creation of an incontinent ileal conduit, continent catheterizable reservoir, or orthotopic neo-bladder utilizing the small or large intestine. While radical extirpation of the bladder is often successful from an oncological perspective, there is significant morbidity associated with enteric interposition within the genitourinary tract. Therefore, there is a great opportunity to decrease the morbidity associated with the current surgical management of bladder cancer by utilizing novel technologies to create a urinary diversion without the intestine. Clinical trials using neo-urinary conduits (NUC) seeded with autologous SMCs are currently in progress and may offer a significant surgical advance by eliminating the complications associated with the use of gastrointestinal segments in urinary reconstruction, simplifying the surgical procedure, and greatly facilitating recovery from cystectomy. A conduit from the ureters to the skin surface addresses the current standard of care while simplifying the surgical procedure, and it may also improve patient outcomes. The NUC created by Tengion serves as a template to catalyze the regeneration of native-like urinary tissue that can connect the ureters to the skin surface. To ensure native urinary tissue regeneration, a biocompatible, biodegradable scaffold with an extended history of safety and clinical utility is necessary. The broadly used PLGA scaffold can enhance tissue regeneration and promote neo-tissue integration when properly seeded with SMCs. The NUC construct has two principal components. The first is the biomaterials. The NUC scaffold is composed of a PGA polymer mesh fashioned into the required tubular shape and coated with a 50/50 blend of PLGA copolymer. The specific structural parameters of the construct can be modified during the surgical procedure according to the patient’s needs. The choice of well-established, synthetic, degradable biopolymers reflects the same requirements for reliability and reproducibility inherent in the choice of these polymers for applications in other bladder-related neo-organs. The second component is the cells. Autologous SMCs sourced from bladder or non-bladder tissue may be applied for NUC construction. Based on the successful outcomes in a porcine cystectomy model, Tengion has initiated phase I clinical trials of NUC constructs in human patients requiring urinary diversion. This phase I study, “Incontinent Urinary Diversion Using an Autologous Neo-Urinary Conduit” (http://​www.​clinicaltrials.​gov/​ct2/​show/​NCT01087697), is currently recruiting patients, with the objective of implanting up to ten patients by the end of 2012. The objective of the study is to evaluate if NUC constructs made using autologous adipose-derived SMCs in combination with defined degradable biomaterial scaffolds can form a functional conduit to safely facilitate passage of urine from the kidneys subsequent to radical cystectomy. Primary outcome indices over a 12-month postimplantation period include structural integrity and conduit patency. CT scans will be used to demonstrate that urine flows safely through the NUC construct. Additional measures of primary outcomes up to 12-month postimplantation include evaluation of any product- or procedure-related adverse events. Similarly, secondary outcome indices will include analysis of NUC structural integrity and patency over a 12–60-month postimplantation period. CT scan and renal ultrasound will be applied to demonstrate that urine flows safely through the NUC construct up to 60 months after implantation. Procedural- and product-related adverse events will also be monitored up to 60 months after implantation. Finally, the overall safety of the NUC construct will be assessed by evaluation of nonproduct-/procedural-related adverse events and patient vital signs.