Feasibility Study of Vascularized Composite Urinary Bladder Allograft Transplantation in a Cadaver Model.

PURPOSE: The purpose of this study was to establish the feasibility of performing a urinary bladder vascularized composite allograft transplantation for either bladder augmentation or neobladder creation. MATERIALS AND METHODS: Six adult cadavers were studied. Cadavers were excluded for any previous pelvic surgery, radiation, vascular surgery or history of pelvic malignancy. An intravascular colored silicone and barium mixture was injected and both computerized tomography scans and gross dissections were performed. Contrast enhanced computerized tomography imaging was used to delineate urinary bladder vascular anatomy variability. Bladders were explanted en bloc from 2 cadavers with bilateral vascular pedicles based on the external iliac vessels and "transplanted" to replicate a bladder transplant. RESULTS: Contrast enhanced 3-D-computerized tomography reconstructions and cadaver dissections revealed distal vascular variability with proximal blood supply based primarily on the internal iliac artery. Urinary bladder vascularized composite allograft transplantation was successfully performed during 2 mock transplants with the vascular anastomosis done to the recipient external iliac artery and vein. CONCLUSIONS: Urinary bladder vascularized composite allograft transplantation is technically and anatomically feasible. This procedure may obviate the use of intestinal segments for bladder reconstruction in select patients. A phase 1 clinical trial is in progress.

Use of pediatric donor en bloc kidneys along with bladder segment in pediatric liver-kidney and multivisceral-kidney transplantation.

The combination of pediatric multivisceral and kidney transplantation leads to additional recipient risks due to the number of anastomoses and to the small sizes of donor structures. The inclusion of donor kidneys, ureters, and a bladder patch en bloc with multivisceral organs decreases the number and complexity of anastomoses and has not yet been reported. Four patients were transplanted in this fashion; three underwent multivisceral-kidney and one underwent liver-kidney transplantation. The first patient was a 3-year-old male with polycystic kidney disease and congenital hepatic fibrosis. The second was a 7-year-old female with complications from necrotizing enterocolitis. The third was a 12-month-old male with megacystis microcolon intestinal hypoperistalsis syndrome and secondary hydronephrosis, and the fourth was a 3-year-old male with multiple intestinal resections secondary to incarcerated hernia. The third patient developed a right ureteral stenosis with an intact bladder patch. The fourth child expired from maintained abdominal sepsis. The first 3 patients maintained normal graft function. There were no cases of thrombosis, arterial stenosis, or urinary leakages. These reported cases demonstrate that small pediatric en bloc transplantation of the multivisceral organs and dual kidneys with a bladder patch anastomosis is a feasible and less complex alternative to the standard procedure.

Effects of topical applications of porcine acellular urinary bladder matrix and Centella asiatica extract on oral wound healing in a rat model.

OBJECTIVES: To evaluate the effects of topical applications of porcine acellular urinary bladder matrix (AUBM) and Centella asiatica extract (CAE) on the healing of tongue wounds in a rat model. MATERIALS AND METHODS: Wounds were made in the tongue using a punch tool in 64 male Sprague-Dawley rats, randomized into four groups (n = 16 per group): group 1 (control), group 2 (CAE), group 3 (AUBM mixed with orabase), and group 4 (orabase). No product was applied in group 1 and groups 2-4 received three daily topical applications. The animals were weighed on day 0 and at the time of euthanasia. Four rats in each group were euthanized at days 2, 7, 14, and 21 and the tongues were processed for: macroscopic morphometric analysis, myeloperoxidase (MPO) and malondialdehyde (MDA) levels, histological wound repair (degree of reepithelialization and inflammation), and CD31 positivity. RESULTS: The animals' weight gain, histological wound repair, and CD31 positivity from greatest to least were: AUBM > CAE > orabase > control. Percentage of tongue occupied by wound, MPO, and MPA levels from least to greatest were: AUBM < CAE < orabase < control, whereby the AUBM group showed significant differences (p ≤ 0.05) in comparison with the other groups on days 2, 7, 14, and 21 for percentage of tongue occupied by wound and MDA and on days 7, 14, and 21 for MPO. CONCLUSIONS: CAE is effective for oral tissue regeneration, while AUBM is an even more potent means of oral mucosa regeneration. CLINICAL RELEVANCE: AUBM may be beneficial to patients with oral wounds; this finding requires further clinical and laboratory investigation.

Managing Ulcers Associated with Pyoderma Gangrenosum with a Urinary Bladder Matrix and Negative-Pressure Wound Therapy.

Pyoderma gangrenosum (PG) is a rare disease that presents as painful ulcerations with inflammation and undermining at the borders. The ulcers can occur anywhere on the body but are most commonly seen on the lower extremities. The etiology of PG is unknown, and there are no definitive diagnostic criteria; PG is a diagnosis of exclusion, which can present serious delays in treatment.Patients should be treated with an interdisciplinary approach with aggressive immunosuppression, treatment of any comorbidities, maximization of nutrition status, reconstructive surgery for treatment of the wound, and physical therapy for deconditioning.This article presents a case study of one patient treated with a porcine urinary bladder matrix and negative-pressure wound therapy; this treatment combination provided pain relief, coverage of the wound, an acceptable aesthetic outcome, and long-term stability.

Bladder Reconstruction with Human Amniotic Membrane in a Xenograft Rat Model: A Preclinical Study.

Background: Human amniotic membranes (HAMs) are assumed to have a number of unique characteristics including durability, hypoallergenic and anti-inflammatory properties. Materials and Methods: Multilayer HAMs from caesarian sections were applied to repair defined bladder defects in male Sprague-Dawley rats. The animals were sacrificed at 7, 21 and 42 days after implantation. Bladder volume capacity after grafting was measured. Histological analyses were performed to asses a number of parameters including HAM degradation, inflammatory reaction, graft rejection and smooth muscle ingrowth. Results: One rat died from sepsis in the treated group. No severe complications or signs of leakage were observed. Bladder capacity did not change over time. The initially increased inflammation in the HAM group diminished significantly over time (p<0.05). No signs of HAM degradation were observed and smooth muscle staining increased over time. Conclusions: HAMs appear to be durable and hypoallergenic grafts. The assumed suitability for the reconstruction of urinary tract justifies further research on detailed immunological process in larger grafts.

Two cases of female urethral reconstruction with acellular porcine urinary bladder matrix.

INTRODUCTION AND HYPOTHESIS: Female urethral reconstruction via the traditional routes can be limiting for various reasons. Current literature on the use of acellular biologic grafts derived from viscera for female urethral reconstruction is limited. We present two cases of women with complete loss of their posterior urethra presenting for urethral reconstruction. METHODS: Two cases of urethral reconstruction using acellular porcine urinary bladder matrix (UBM), along with labial fat pad transposition and biologic pubovaginal sling are presented. RESULTS: In both cases the UBM graft showed successful conversion to what appeared to be normal urethral mucosa. One woman showed significant improvement in continence and the other showed complete continence. CONCLUSIONS: Female urethral reconstruction using acellular porcine UBM is a viable option for patients who have lost a significant portion of their urethra. Both cases demonstrated transition of the graft into the posterior wall of the urethra with significant improvement in continence. Further studies are needed to confirm that acellular porcine UBM can transform to urethral mucosa in women requiring urethral reconstruction.

Embryonic kidney function in a chronic renal failure model in rodents.

BACKGROUND: Rapid advancements have been made in alternative treatments for renal diseases. Our goal for renal regeneration is to establish a kidney graft derived from human embryonic tissues. In this study, we investigated the effects of host renal failure on the structure and activity of transplanted embryonic kidney and bladder, and found that diuretics effectively induced urine production in the transplanted kidney. METHODS: Uremic conditions were reproduced using a 5/6 renal infarction rat model. An embryonic kidney plus bladder (embryonic day 15) was isolated from a pregnant Lewis rat and transplanted into the para-aortic area of a 5/6 renal-infarcted Lewis rat. Following growth, the embryonic bladder was successfully anastomosed to the host ureter. RESULTS: We assessed graft function in terms of survival rates and found no differences between normal (n = 5) and renal failure (n = 8) groups (median survival: 70.5 vs 74.5 h; p = 0.331) in terms of survival, indicating that the grafts prolonged rat survival, even under renal failure conditions. Furosemide (n = 9) significantly increased urine volume compared with saline-treated controls (n = 7; p < 0.05), confirming that the grafts were functional. We also demonstrated the possibilities of an in vivo imaging system for determining the viability of transplanted embryonic kidney with bladder. CONCLUSION: The results of this study demonstrate that transplanted embryonic kidney and bladder can grow and function effectively, even under uremic conditions.

Ureteral reconstruction using a tapered non-vascularized bladder graft: an experimental study in a canine animal model.

BACKGROUND: Reconstruction of ureteral defects and strictures remains problematic for urologists. We aimed to investigate the possibility of a tapered non-vascularized bladder graft as a novel substitute for ureteral reconstruction. METHODS: This experimental study was conducted on nine beagles. Under general anesthesia, a full-thickness graft with 5-6 cm in length was disassociated from the anterior upper wall of the bladder, and tapered into 1/3 to 1/2 thickness, remaining the urothelial surface. After removal of 5 cm of right-sided mid-ureter, the tapered bladder graft was tubularized along the long axis and then respectively anastomosed to the upper and lower stumps of the ureter. A retrograde urography through a cystostomy was performed 8 weeks after the ureteral reconstruction. The animals were euthanized, and histopathologic examinations of the neoureters were performed. RESULTS: There were no severe complications during postoperative follow-up. The urography indicated patent urine excretion and no fistula or stenosis. Histopathologic examinations of the neoureters showed open lumen with urothelial lining. Nutrient vessels were observed in healthy submucosa, lamina muscularis and peripheral connective tissue. CONCLUSIONS: Our study implied that ureteral reconstruction by a tapered non-vascularized bladder graft was anatomically possible in our animal model. Further studies are expected to confirm long-term and functional outcomes.

The Use of Acellular Urinary Bladder Matrix as Coverage for Fasciocutaneous Free Flap Donor Sites: An Alternative to Traditional Grafting Procedures.

PURPOSE: The purpose of this review is to 1) evaluate our early experience with urinary bladder matrix as a dressing for the management of complex wounds subsequent to fasciocutaneous or osteocutaneous vascularized tissue harvests, 2) assess coverage of exposed tendons and the duration of granulation and epithelial coverage, and 3) assess esthetic and functional outcomes compared with traditional means for the management of vascularized tissue harvest sites. PATIENTS AND METHODS: This prospective study consisted of 8 consecutive patients in whom a substantial cutaneous component was harvested as part of a vascularized tissue reconstruction, which did not permit for primary closure (n = 7) or had skin graft failure (exposed tendon) that required additional treatment (n = 1). RESULTS: Functional and esthetic outcomes were comparable to those of traditional methods of donor site closure as determined by clinical evaluation and subjective assessment by the patient. In all patients, no additional grafting was required to achieve full coverage. Irregularities of the wound achieved a level plane with granulation tissue an average of 3 to 4 weeks after surgery, followed by an additional 5 to 8 weeks for epithelialization. Wound care was minimal and included twice-daily wet-to-dry dressings. It was noted that complete wound healing was delayed in the urinary bladder matrix group, which required more attention during wound care when compared with published data. Advantages included facilitation of a robust granulation layer that leveled wound irregularities and avoidance of an additional skin graft site. CONCLUSIONS: The use of urinary bladder matrix is a viable option for the rehabilitation of donor sites of vascularized tissue that include skin. Benefits include the avoidance of an additional skin graft donor site, facilitation of epithelialization over exposed tendons, leveling of the donor site texture, and an equivalent esthetic result compared with current practices for wound coverage. The success of this technique may be limited by the cost of materials and the protracted course for wound epithelialization.

Cystometric analysis of the transplanted bladder.

OBJECTIVE: cystometric evaluation of the bladder after autotransplant and isogeneic transplant in female rats. MATERIAL AND METHODS: two groups were constituted: (A) bladder autotransplant with two subgroups: R1 - (control) and R2 - (bladder transplant); (B) isogeneic bladder transplant with three subgroups; T1 - (control); T2-T3, two subgroups observed for 30 and 60 days after transplant, respectively. All animals underwent cystometric evaluation. Afterwards, the bladders were removed for histological study. RESULTS: the transplanted bladders did not show significant changes in filling/storage and emptying/micturition functions after 30 and 60 days of evolution. Upon macroscopical evaluation, there was good revascularization and the tissue was well preserved. Cystometry results: did not show significant differences in the micturition pressure in subgroups T2-T3, but did between subgroups R1-R2, T1-T2, and T1-T3. Significant differences were verified in the micturition interval between T1-T3, T2-T3, but not between R1-R2, T1-T2. There was significant difference in the micturition duration between T1-T3 but not between R1-R2, T1-T2 and T2-T3. No fistula was noted on the suture site nor leakage of urine in the abdominal cavity or signs of necrosis or retraction were observed. CONCLUSIONS: transplant of the bladder was shown to be a viable procedure. The results indicate that there was structural and functional regeneration of transplanted bladders, and these results indicate that it is possible that vascular endothelium growth and neurogenesis factors are involved and activated in the process of the preservation or survival of the transplanted organ.

New technique for needle-less implantation of eukaryotic cells.

BACKGROUND AIMS: On review of the use of stem cells in the literature, promissory outcomes for functional organ recovery in many subspecialties in medicine underscore its therapeutic potential. The application of stem cells through the use of a needle can result in additional scar formation, which is undesired for delicate organs. The present work describes the use of a needle-less stem cell injector with the Immediate Drop on Demand Technology (I-DOT) for cell injection in vitro. METHODS: Mesenchymal stromal cells from human bone marrow were labeled with ethynyl-deoxyuridine (EdU) for 2 days and then were re-suspended. With the use of I-DOT, the cells were applied to type 1 collagen matrices or pig bladder tissue specimens with or without mucosa at different levels of energy. The collagen matrices were analyzed after 4 h and 5 days; bladder tissue specimens were analyzed 4 h after cell implantation. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test (MTT) assay was performed immediately after cell application to the collagen matrices. Histological analysis with the use of frozen sections and immunofluorescence was used to localize EdU-labeled cells. RESULTS: A considerable number of cells were detected by use of the MTT assay for collagen matrices. In the collagen matrix, the mean measured depth immediately after application ranged between 210 µm and 489 µm, 220 µm and 270 µm for entire bladder specimens, and 230 µm and 370 µm for bladder without mucosa. Cells survived for up to 5 days in the collagen matrix in both bladder specimens. CONCLUSIONS: Cells can survive during I-DOT application, which suggests that the I-DOT device may be a potentially suitable technology for needle-less cell application onto tissues.

Free tubularised vesical mucosa graft for congenital stenosis of the urethra in children.

BACKGROUND: Reconstruction of urethral strictures in children remains a challenge to the pediatric surgeon as these are often related to different rare congenital anomalies with various clinical presentations that endanger renal function and should be repaired in young children. Multiple techniques have been described for their repair. We aimed to determine whether the use of a free tubularised bladder mucosal graft associated to a prior tubeless vesicostomy was feasible and sure, as this technique of reconstruction using tubularised grafts has not been described yet in young children. RESULTS: Two newborn male patients were referred to our department. Both presented a congenital stenosis of the urethra as a part of a complex urethral malformation. Surgery involved prior tubeless vesicostomy, free bladder mucosal graft for urethral reconstruction, and vesicostomy closure for both children. Postoperative evolution was satisfying in both children and cystourethroscopy showed permeable urethra. Satisfying cosmetic and functional results have been obtained in the two cases. CONCLUSIONS: The prior vesicostomy prevents kidney damage in the context of complex genital and urinary malformations. Bladder mucosa's immunohistological properties are the most similar to those of the urethral tissue, and are appropriate for this type of correction, making our technique feasible and sure. LEVEL OF EVIDENCE: 5.

Update on tissue engineering in pediatric urology.

Pediatric urology patients often present with congenital or acquired tissue and organ dysfunction that requires surgical reconstruction to recreate the normal genitourinary systems functions. The traditional methods have varying degrees of donor site morbidity or inherent side effects. Tissue engineering is a developing field that aims to replace or regenerate these dysfunctional tissues and organs with cells, biomaterials, or a combination thereof. A tremendous amount of work has been done to these ends in terms of preclinical work, and some clinical trials have resulted. This review highlights the status of these studies in pediatric urology for the use of tissue engineering and reconstruction of the corporal bodies, urethra, and bladder.

Urethral reconstruction using allogenic frozen-thawed bladder mucosa: an experimental study.

OBJECTIVE: To determine the feasibility and effectivity of allogenic frozen-thawed bladder mucosa for urethroplasty. METHODS: Bladder mucosa was harvested from 6 New Zealand rabbits. Changes in the bladder mucosa as seen by histological and electron microscope examination were compared between the frozen-thawed and fresh groups. Twelve urethral stricture models were established and randomly divided into two groups. In the test group, we performed urethroplasty with allogenic frozen-thawed bladder mucosa, and the same operation was done in the control group, but using fresh bladder mucosa. The result of retrograde urethrography and histological changes of the urethral sample were compared postoperatively. RESULTS: No obvious changes on histological and electron microscope examination were observed in the frozen-thawed bladder mucosa. Inflammation reaction of the surgical site in the test group was milder than that of the controls 2 weeks after surgery. The urethral epithelial cells grew well 2 weeks after surgery, but lots of epithelia were necrotic in the control group. The urethra of all rabbits in the test group had good continuity and the urethral lumen was large in the test group 2 months after surgery. There was a layer of urethral epithelium in the test group 2 months after surgery, whereas scar tissue was found in the control group. CONCLUSIONS: The freeze-thaw technique can maintain bladder mucosa structure and biological function. Frozen-thawed allogenic bladder mucosa may be a potential material for urethroplasty.

Epithelium-free bladder wall graft: epithelial ingrowth and regeneration--clinical implications for partial cystectomy.

PURPOSE: Most patients who need a bioengineered bladder wall have bladder cancer. A graft made with autologous urothelium would not be safe. To investigate the feasibility of providing bioengineered tissue for patients with partial cystectomy we evaluated the host and graft response after transplanting an epithelium-free graft. MATERIALS AND METHODS: De-epithelialized bladder wall grafts from male rats were transplanted on syngeneic female rat bladders after partial cystectomy. Urothelial morphology, vessel density, inflammation, stromal thickness and uroplakin expression were evaluated 1, 3, 6 and 9 months after surgery. Cell gender was distinguished by fluorescent in situ hybridization using unique X and Y chromosome probes. RESULTS: There was no significant graft contraction at any time. Male graft urothelial morphology and uroplakin expression were similar to those of controls at all time points. The donor bladder had decreased vessel density at early time points while the host had increased vascularity, which normalized in each by 6 months. Graft inflammation and edema normalized by 9 months. There was no muscular hypertrophy. Fluorescence in situ hybridization revealed early ingrowth of host female urothelium and a small fraction of male urothelial cells, which appeared between 1 and 3 months. CONCLUSIONS: Within 9 months de-epithelialized grafts appeared histologically as normal bladder, surprisingly faster than an equivalent model with full-thickness grafts. The safety and function of an epithelium-free graft must be determined in a large animal model. These early data in a small animal model substantiate the feasibility and equivalency of using grafts without epithelium, which would allow application in patients with cancer.

Simultaneous implantation of bilateral ureters into bladder acellular matrix graft after partial cystectomy in a porcine model.

UNLABELLED: What's known on the subject? and What does the study add? The process of bladder regeneration with a bladder acellular matrix graft (BAMG) is thought to be accelerated by administration of vascular endothelial growth factor into the host bladder. In the present study, we showed that simultaneous implantation of bilateral ureters into a BAMG after a partial cystectomy is reasonable and provides an increased opportunity to the bio-scaffold for communication with host tissues from which a blood supply and stem cells will be generated. OBJECTIVE: • To evaluate if the implantation of bilateral ureters into a bladder acellular matrix graft (BAMG) at the time of its implantation would enhance bladder regeneration in a partial substitution BAMG. MATERIALS AND METHODS: • Partial cystectomies were performed under general anaesthesia in 12 pigs, followed by augmentation with a BAMG. • Six (ureteric implantation group) also received simultaneous implantation of bilateral ureters into the BAMG, while the remaining six (control group) did not have ureteric implantation. • In both groups, bladder regeneration was evaluated using endoscopic and histopathological methods at 1, 2, 4, and 8 weeks after implantation. RESULTS: • At 1 week after BAMG implantation, there were significant inflammatory changes on the host bladder in both groups, while no significant endoscopic changes were seen on the BAMG luminal surfaces. • At 2 weeks, inflammatory changes were diminished and epithelialisation on the BMAG was identified, especially near the host bladder in both groups. • Similarly, epithelialisation on the BAMG near the implanted ureters was seen in the ureteric implantation group. • At 4 and 8 weeks, epithelialisation remained in progress in both groups, although it was more active and expansive in the ureteric implantation group. CONCLUSIONS: • In our porcine model, endoscopic and histopathological examinations showed that simultaneous implantation of bilateral ureters into a BAMG enhanced epithelialisation of the AMG. • This new approach using host ureters and bladder as a potential source of bladder regeneration may provide for rapid and complete regeneration of a bladder substitute.

The effect of programmed cryopreservation on immunogenicity of bladder mucosa in New Zealand rabbits.

A significant reduction in immunogenicity has been observed in some frozen-thawed tissues after cryopreservation. The objective of this study was to evaluate the effects of programmed cryopreservation on immunogenicity of rabbit bladder mucosa and on the extent of immunological rejection caused by the allograft. This study would provide theoretical support for the application of allogenic frozen-thawed bladder mucosa in the treatment of urethral stricture. Forty-two adult male New Zealand rabbits were used in this study. The immunogenicity was detected by mixed lymphocyte reaction using the allograft of bladder mucosa (fresh and frozen-thawed) and spleen lymphocytes. Twelve urethral stricture models were established in New Zealand rabbits for substitution urethroplasty using the allograft of bladder mucosa, which were divided into fresh and frozen-thawed group. Two weeks after operation, lymphocyte proliferation was detected in both blood and spleen of recipient rabbits. At the same time, immunohistochemical staining of urethral allograft was performed and the expression of CD3, CD4 and CD8 were observed. The mRNA of bladder mucosa (fresh and frozen-thawed) was extracted and the expressions of RLA-I, RLA-II and RLA-III gene were detected by real-time PCR. By mixed lymphocyte reaction, we found that allogenic lymphocyte proliferation stimulated by frozen-thawed bladder epithelial cells was significantly weaker than that of the fresh cells. The blood and spleen lymphocytes from fresh bladder mucosa group showed significantly higher proliferation rate than frozen-thawed group. Compared with the fresh group, the expression of CD3+ and CD8+ T cells infiltrated in the operation locus of bladder mucosa urethroplasty was significantly decreased in the frozen-thawed group. However, the expressions of RLA genes did not change significantly after the freeze-thaw procedure. This study demonstrates for the first time that a programmed freeze-thaw procedure of rabbit bladder mucosa could reduce its immunogenicity in allogenic bladder mucosa urethroplasty and thus restrict the extent of immunological rejection, therefore, provides theoretical support for the application of frozen-thawed bladder mucosa in the treatment of urethral stricture.

Autologous urothelial cells transplantation onto a prefabricated capsular stent for tissue engineered ureteral reconstruction.

In this study, we have fabricated an artificial ureter by transplantation of in vitro-expanded urothelial cells onto an in vivo-prefabricated capsular stent using tissue engineering methods. Spiral poly (L-lactic acid) (PLLA) stents were transplanted into the subcutaneous of Wistar rats for a period of 1, 2 or 3 weeks to induce the formation of connective tissue capsules on their surfaces. The capsular PLLA stents were then decellularized and further recellularized with bladder epithelial cells to fabricate artificial ureters. The results showed that the entrapped cells in all capsules remained continuously proliferation and lined up in continuous layers. In addition, the urothelial cells on the capsular stents with an embedding period of 2 or 3 weeks showed higher proliferative viability compared with the cells on the stents with an embedding time of 1 week (P < 0.05). The results of the study indicated that the prefabricated capsular stents could serve as alternative cell carriers for tissue engineered ureters, especially with embedding time from 2 to 3 weeks.

Characterization of the deposition of collagen fibers and lithogenic potential in bladder of rats submitted to a sugar cane biopolymer graft.

OBJECTIVES: Suture materials are widely used in urology. The interaction of these materials with the extracellular matrix in the inflammatory process can be estimated by stereology of collagen fibers and the present study was designed to determine the behavior of the bladder tissue of rats to grafts of the biopolymer of sugar cane (BPCA), and the inflammation and intravesical stone formation compared to the polyglactin 910. MATERIALS AND METHODS: 42 Wistar rats were divided in four groups: Group I (n = 10) rats submitted to bladder implantation of ~4-0 BPCA suture graft and euthanized at 4 weeks; Group II (n = 10) rats submitted to bladder implantation of 4-0 polyglactin 910 suture graft and euthanized at 4 weeks; Group III (n = 12) rats submitted to bladder implantation of ~4-0 BPCA suture graft and euthanized at 8 weeks; Group IV (n = 10) rats submitted to bladder implantation of 4-0 polyglactin 910 suture graft and euthanized at 8 weeks. Bladders collected at necropsy were analyzed for their weight and the presence of grafts and calculi. Sections were prepared for stereological analysis of collagen fibers. RESULTS: The bladder weight was higher in group I, particularly in the presence of bladder stones. The presence of the graft was observed in 100 % (group I), 80 % (group II), 91.6 % (group III) and 30 % (group IV); polyglactin 910 showed an absorption of 70 % in this period. The stereological analysis showed a higher volume density of collagen fibers in group I versus other groups (p < 0.001). CONCLUSION: The BPCA was a material with good integration into the bladder of rats; its absorption was slower than that of the polyglactin 910. The presence of urinary stones was lower in bladders with implantation of BPCA, particularly after 8 weeks. There was a greater initial inflammatory response to BPCA graft that was directly related to the increase in bladder weight and the presence of urinary stones, but that equalized the results of polyglactin 910 after 8 weeks.

Tissue engineering of human bladder.

There are a number of conditions of the bladder that can lead to loss of function. Many of these require reconstructive procedures. However, current techniques may lead to a number of complications. Replacement of bladder tissues with functionally equivalent ones created in the laboratory could improve the outcome of reconstructive surgery. A review of the literature was conducted using PubMed to identify studies that provide evidence that tissue engineering techniques may be useful in the development of alternatives to current methods of bladder reconstruction. A number of animal studies and several clinical experiences show that it is possible to reconstruct the bladder using tissues and neo-organs produced in the laboratory. Materials that could be used to create functionally equivalent urologic tissues in the laboratory, especially non-autologous cells that have the potential to reject have many technical limitations. Current research suggests that the use of biomaterial-based, bladder-shaped scaffolds seeded with autologous urothelial and smooth muscle cells is currently the best option for bladder tissue engineering. Further research to develop novel biomaterials and cell sources, as well as information gained from developmental biology, signal transduction studies and studies of the wound healing response would be beneficial.