The 17-Gene Genomic Prostate Score Test Is Prognostic for Outcomes After Primary External Beam Radiation Therapy in Men With Clinically Localized Prostate Cancer.

PURPOSE: The Oncotype DX Genomic Prostate Score (GPS) assay has been validated as a strong prognostic indicator of adverse pathology, biochemical recurrence, distant metastasis (DM), and prostate cancer (PCa)-related death (PCD) in men with localized PCa after radical prostatectomy. However, it has yet to be tested in men undergoing external beam radiation therapy (EBRT), for whom assessing PCa progression risk could inform decisions on treatment intensity. We analyzed whether GPS results are associated with time to biochemical failure (BCF), DM, and PCD after EBRT in men with localized PCa and whether the association is modified by race. METHODS AND MATERIALS: We conducted a retrospective study of men with localized PCa treated with EBRT at the VA Health Care System in Durham, NC from 2000 to 2016. Study endpoints were time to BCF per the Phoenix criteria, DM, and PCD. The association of GPS results, per 20-unit increase or dichotomous variable (0-40 vs 41-100), was evaluated with each endpoint using univariable and multivariable Cox proportional hazards models. Results were then stratified by race. RESULTS: A total of 238 patients (69% Black) met the eligibility criteria. Median follow-up for patients who did not experience BCF was 7.6 years. GPS results per 20-unit increase were significantly associated with BCF (hazard ratio [HR], 3.62; 95% confidence interval [CI], 2.59-5.02), DM (HR, 4.48; 95% CI, 2.75-7.38), and PCD (HR, 5.36; 95% CI, 3.06-9.76) in univariable analysis. GPS results remained significant in multivariable models adjusted for baseline clinical and pathological factors, with HRs being similar to the univariable analysis. There was no significant interaction between the GPS assay and race (P = .923). HRs for BCF were similar in Black men (HR, 3.88; 95% CI, 2.40-6.24) versus non-Black men (HR, 4.01; 95% CI, 2.42-6.45). CONCLUSIONS: Among men treated with EBRT, the GPS assay is a strong, independent prognostic indicator of time to BCF, DM, and PCD, and performs similarly in Black and non-Black men.

The 17-gene Genomic Prostate Score assay as a predictor of biochemical recurrence in men with intermediate and high-risk prostate cancer.

The validated 17-gene Oncotype DX Genomic Prostate Score® (GPS™) assay risk-stratifies prostate-cancer patients with localized disease. The assay has primarily been utilized in lower risk patients deciding between active surveillance versus definitive therapy. In this retrospective cohort study, we analyze the association of the GPS result with time to biochemical recurrence post-prostatectomy in patients with National Comprehensive Cancer Network® (NCCN) intermediate and higher risk prostate cancer. The 141 patients included in the study were from the NorthShore University HealthSystem diagnosed 2014-2019 with NCCN intermediate (n = 109) or higher risk (n = 32) prostate cancer, treated with radical prostatectomy 2015-2019. The association of GPS result with time to biochemical recurrence was evaluated using univariable and multivariable Cox proportional hazards models in 120 patients with unfavorable intermediate or higher risk. Median (interquartile range) follow-up time was 28 (20 to 38) months. The GPS result was significantly associated with time to biochemical recurrence as both a continuous and dichotomous variable in univariable (hazard ratio [HR] per 20 GPS units 2.36, 95% CI 1.45-3.80, p < 0.001; HR for GPS result 41-100 vs 0-40 3.28, 95% CI 1.61-7.19, p < 0.001) and in multivariable models accounting for NCCN risk group (HR per 20 GPS units 2.14, 95% CI 1.31-3.46, p = 0.003; HR for GPS result 41-100 vs 0-40 3.00, 95% CI 1.43-6.72, p = 0.003) or biopsy Gleason Score and diagnostic PSA or PSA density. These results indicate that the GPS assay was a strong predictor of biochemical recurrence after radical prostatectomy in this unfavorable intermediate and higher risk prostate cancer patient population.

Validating the association of adverse pathology with distant metastasis and prostate cancer mortality 20-years after radical prostatectomy.

PURPOSE: To assess the association of adverse pathology (AP), defined as high-grade (≥ Gleason Grade Group 3) and/or non-organ confined disease, with long-term oncologic outcomes after radical prostatectomy (RP). MATERIALS AND METHODS: Using a stratified cohort sampling design, we evaluated the association of AP with the risk of distant metastasis (DM) and prostate cancer-specific mortality (PCSM) up to 20 years after RP in 428 patients treated between 1987 to 2004. Cox regression of cause-specific hazards was used to estimate the absolute risk of both endpoints, with death from other causes treated as a competing risk. Additionally, subgroup analysis in patients with low and/or intermediate-risk disease, who are potentially eligible for active surveillance (AS), was performed. RESULTS: Within the cohort sample, 53% of men exhibited AP at time of RP, with median follow up of 15.5 years (IQR 14.6-16.6 years) thereafter. Adverse pathology was highly associated with DM and PCSM in the overall cohort (HR 12.30, 95% confidence interval [CI] 5.30-28.55, and HR 10.03, 95% CI 3.42-29.47, respectively, both P < 0.001). Adverse pathology was also highly associated with DM and PCSM in the low/intermediate-risk subgroup (HR 10.48, 95% CI 4.18-26.28, and 8.60, 95% CI 2.40-30.48, respectively, both P < 0.001). CONCLUSIONS: Adverse pathology at the time of RP is highly associated with future development of DM and PCSM. Accurate prediction of AP may thus be useful for individualizing risk-based surveillance and treatment strategies.

GPS Assay Association With Long-Term Cancer Outcomes: Twenty-Year Risk of Distant Metastasis and Prostate Cancer-Specific Mortality.

PURPOSE: To assess the association between the Oncotype DX Genomic Prostate Score (GPS) result and long-term oncological outcomes following radical prostatectomy (RP). METHODS: We evaluated the association of the GPS result assayed from the index lesion from RP tissue with the risk of distant metastases (DM) and prostate cancer-specific mortality (PCSM) over the 20 years following RP in a stratified cohort sample of 428 patients from 2,641 treated between 1987 and 2004. Cox regression of cause-specific hazards was used to estimate the absolute risk of both end points, with death from other causes treated as a competing risk. A correction for regression to the mean (RM) was applied since the GPS test was developed using this cohort. Exploratory analysis using presurgical parameters and the GPS test as prognostic variables was performed to assess the additional value of the GPS test on 20-year risk of DM and PCSM. Model discrimination was measured using the area under the receiver operating characteristic curve. RESULTS: The GPS test appears to be independently associated with both 20-year risk of DM and PCSM with a low false discovery rate. Per 20-unit increase in GPS, multivariable analysis with RM correction estimated hazard ratios of 2.24 (95% CI, 1.49 to 3.53) and 2.30 (95% CI, 1.45 to 4.36) for DM and PCSM, respectively. Accuracy of models including clinical risk factors alone appeared to improve when including the GPS test in assessing risk of both end points. CONCLUSION: The results suggest that the GPS test provides information on the risk for the meaningful long-term outcomes of DM and PCSM.

The 17-Gene Genomic Prostate Score Test as a Predictor of Outcomes in Men with Unfavorable Intermediate Risk Prostate Cancer.

OBJECTIVES: To evaluate the association of the Genomic Prostate Score (GPS) assay result with biochemical recurrence (BCR), distant metastases (DM), and prostate-specific death (PCD) in unfavorable intermediate (UFI) risk prostate cancer patients. The GPS assay is used to help guide management decisions for newly diagnosed low and favorable intermediate (FI) risk disease. METHODS: GPS results from 2 studies (Center for Prostate Disease Research [CPDR]; Kaiser Permanente Northern California [KPNC]) in men treated with radical prostatectomy were analyzed to determine associations of the GPS result with BCR, DM, and PCD in UFI risk disease. Analyses included 299 intermediate risk prostate patients, 175 of whom had UFI risk disease (KPNC = 103; CPDR = 72). RESULTS: The GPS result as a dichotomous value (≤40 vs >40) was a significant predictor of BCR in UFI patients in multivariate analyses (hazard ratio [HR] 6.0; 95% confidence interval [CI] 2.0-22.4; P = .0035; CPDR). The GPS result was a strong predictor of all 3 endpoints in multivariate analyses (BCR HR 7.1; 95% CI 5.7-8.8; P < .0001; DM HR 5.4; 95% CI 3.8-7.8; P < .0001; PCD HR 3.4; 95% CI 1.5-8.9; P = .006; KPNC). UFI patients with GPS >40 had outcomes consistent with high-risk disease, whereas UFI patients with GPS ≤40 had outcomes similar to FI risk patients (CPDR/KPNC). CONCLUSIONS: The GPS result was a strong independent predictor of BCR, DM, and PCD in intermediate risk prostate cancer. UFI patients with GPS >40 have a poor prognosis and may benefit from additional therapeutic options.

Clean intermittent catheterization rates after initial and subsequent treatments with onabotulinumtoxinA for non-neurogenic overactive bladder in real-world clinical settings.

OBJECTIVE: Previous randomized controlled trials have reported a 6.1-6.9% incidence of clean intermittent catheterization (CIC) following treatment with onabotulinumtoxinA in non-neurogenic overactive bladder (OAB) patients who were inadequately managed by ≥1 anticholinergic. A multi-center retrospective chart review assessed the real-world rate of voiding dysfunction requiring catheterization. METHODS: Patients received onabotulinumtoxinA 100 U (approved dose) administered by experienced injectors between January 2013 and June 2015. Patients using CIC or an indwelling catheter for ≥24 hours for voiding dysfunction prior to onabotulinumtoxinA injections were excluded. The primary outcome was post-treatment CIC (lasting >24 hours; per individual physician's clinical judgment considering patient's voiding symptoms, post-void residual [PVR] urine volumes and patient bother). Potential baseline predictors of CIC (history of pelvic prolapse, cystocele, diabetes, PVR urine volume and age) were assessed using multivariable logistic regression. RESULTS: Overall, 299 patients received their first treatment with onabotulinumtoxinA 100 U. Mean age was 66.4 years; 98.3% were female. The incidence of CIC was 2.7% in the total study population after the first treatment with onabotulinumtoxinA. The de novo CIC rate in treatments 2 and 3 combined was similarly low (3.2%). None of the evaluated baseline characteristics were significant predictors of CIC initiation due to the low CIC incidence. CONCLUSIONS: This real-world study of non-neurogenic OAB patients treated with onabotulinumtoxinA suggests that the CIC rate is lower than the rates reported in previous studies. There were no significant correlations between baseline predictors and CIC initiation, although statistical significance may not have been reached because of the low incidence of CIC.

Repopulation of porcine kidney scaffold using porcine primary renal cells.

The only definitive treatment for end stage renal disease is renal transplantation, however the current shortage of organ donors has resulted in a long list of patients awaiting transplant. Whole organ engineering based on decellularization/recellularization techniques has provided the possibility of creating engineered kidney constructs as an alternative to donor organ transplantation. Previous studies have demonstrated that small units of engineered kidney are able to maintain function in vivo. However, an engineered kidney with sufficient functional capacity to replace normal renal function has not yet been developed. One obstacle in the generation of such an organ is the development of effective cell seeding methods for robust colonization of engineered kidney scaffolds. We have developed cell culture methods that allow primary porcine renal cells to be efficiently expanded while maintaining normal renal phenotype. We have also established an effective cell seeding method for the repopulation of acellular porcine renal scaffolds. Histological and immunohistochemical analyses demonstrate that a majority of the expanded cells are proximal tubular cells, and the seeded cells formed tubule-like structures that express normal renal tubule phenotypic markers. Functional analysis revealed that cells within the kidney construct demonstrated normal renal functions such as re-adsorption of sodium and protein, hydrolase activity, and production of erythropoietin. These structural and functional outcomes suggest that engineered kidney scaffolds may offer an alternative to donor organ transplant. STATEMENT OF SIGNIFICANCE: Kidney transplantation is the only definitive treatment for end stage renal disease, however the current shortage of organ donors has limited the treatment. Whole organ engineering based on decellularization/recellularization techniques has provided the possibility of creating engineered kidney constructs as an alternative to donor organ transplantation. While previous studies have shown that small units of engineered kidneys are able to maintain function in animal studies, engineering of kidneys with sufficient functional capacity to replace normal renal function is still challenging due to inefficient cell seeding methods. This study aims to establish an effective cell seeding method using pig kidney cells for the repopulation of acellular porcine kidney scaffolds, suggesting that engineered kidneys may offer an alternative to donor organ transplant.

The potential utility of non-invasive imaging to monitor restoration of bladder structure and function following subtotal cystectomy (STC).

BACKGROUND: Restoration of normal bladder volume and function (i.e., bioequivalent bladder) are observed within 8 weeks of performing subtotal cystectomy (STC; removal of ~70 % of the bladder) in 12-week old rats. For analysis of bladder function in rodents, terminal urodynamic approaches are largely utilized. In the current study, we investigated the potential for Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans to noninvasively track restoration of structure and function following STC. METHODS: Twelve week old female Fisher F344 rats underwent STC and were scanned via CT and/or MRI 2, 4, 8, and 12 weeks post-STC, followed by urodynamic testing. After euthanasia, bladders were excised for histological processing. RESULTS: MRI scans demonstrated an initial decline followed by a time-dependent increase to normal bladder wall thickness (BWT) by 8 weeks post-STC. Masson's trichrome staining showed a lack of fibrosis post-STC, and also revealed that the percent of smooth muscle in the bladder wall at 2 and 4 weeks positively correlated with pre-operative baseline BWT. Moreover, increased BWT values before STC was predictive of improved bladder compliance at 2 and 4 weeks post-STC. Cystometric studies indicated that repeated MRI manipulation (i.e. bladder emptying) apparently had a negative impact on bladder capacity and compliance. A "window" of bladder volumes was identified 2 weeks post-STC via CT scanning that were commensurate with normal micturition pressures measured in the same animal 6 weeks later. CONCLUSIONS: Taken together, the data indicate some limitations of "non-invasive" imaging to provide insight into bladder regeneration. Specifically, mechanical manipulation of the bladder during MRI appears to negatively impact the regenerative process per se, which highlights the importance of terminal cystometric studies.

Can computed tomography--assisted virtual endoscopy be an innovative tool for detecting urethral tissue pathologies?

OBJECTIVE: To test if virtual endoscopy (VE) enabled by 3-dimensional computed tomographic (CT) scanner with supporting software allows for practical clinical interrogation and evaluation of the urethral lumen and anatomy in an animal model. METHODS: Assessment of urethral anatomy and repair results was performed in 18 male beagles using conventional retrograde urethrography, CT-assisted retrograde urethography, and voiding urethrocystography. The image slices from these studies were processed using TeraRecon software to create a virtual representation of the urethra and compared with conventional urethrography and postmortem analysis of retrieved urethras for diagnostic assessment and correlation. RESULTS: CT-assisted VE showed the orientation, size, and gross morphology of urethral anatomy, including the lesions in all the 18 animals studied. The VE showed patent urethra in 12 dogs, stenosed urethra in 3 dogs, urethral diverticulum with stricture in 2 animals, and fistula in one. These findings correlated with those of conventional diagnostic methods. The findings of the voiding and retrograde virtual urethrocystoscopy studies were also comparable. CONCLUSION: These results demonstrate that CT-assisted VE is able to identify the anatomic landmarks in an animal model. This allows for detection of the site of different pathologies and their relations to important structures such as urethral sphincters and the bladder neck. Digital imaging might be used to identify urethral pathologies with greater details and characterization of the lesions when compared with the conventional urethrocystography.

Adipose-derived stem cells (ADSCs) and muscle precursor cells (MPCs) for the treatment of bladder voiding dysfunction.

PURPOSE: Bladder outflow obstruction (BOO) is common in the elderly and can result in bladder voiding dysfunction (BVD) due to severe bladder muscle damage. The goal of this research was to evaluate the use of adult stem cells for the treatment of BVD due to decreased muscle contractility in a rat model. MATERIALS AND METHODS: Adipose-derived stem cells (ADSCs) and muscle precursor cells (MPCs) were harvested from male Lewis rats and expanded in culture. BOO was induced by tying a suture around the urethra. Six weeks after obstruction, the development of BVD was confirmed by cystometric analysis in conscious rats, histology and molecular investigations. Injection of ADSCs or MPCs into the bladder wall and synchronous deligation was performed 6 weeks after the obstruction. After stem-cell treatment, morphological and functional changes were assessed. Age-matched rats and animals without cellular therapy but deligation-only served as controls. RESULTS: Voiding pressures decreased progressively 6 weeks after obstruction with increased bladder capacities. Structural changes of the detrusor muscle occurred during the time of obstruction with an increased connective tissue-to-smooth muscle ratio and decreased SMA/smoothelin expression. After stem-cell injection, improved voiding pressures and voiding volumes were observed together with recovered tissue architecture. RT-PCR and Western blotting showed an up-regulation of important contractile proteins. CONCLUSIONS: We established a reliable model for BVD and demonstrated that ADSCs and MPCs can prevent pathophysiological remodelling and provide regenerated bladder tissue and function.

Age-related alterations in regeneration of the urinary bladder after subtotal cystectomy.

Prior work documented that surgical removal of approximately 70% of the bladder (subtotal cystectomy) in 12-week-old female rats induced complete functional regeneration of the bladder within 8 weeks. To determine whether animal age affects bladder regeneration, female F344 rats aged 12 weeks (young) and 12 months (old) underwent subtotal cystectomy, and then were evaluated from 1 to 26 weeks after subtotal cystectomy. At 26 weeks after subtotal cystectomy, bladder capacity in young animals was indistinguishable from that in age-matched controls, but bladder capacity in old animals was only approximately 56% of that in age-matched controls. There was no detectable difference in residual volume among treatment groups, but the diminished regeneration in old animals was associated with a corresponding increase in the ratio of residual volume to micturition volume. The majority of old animals exhibited evidence of chronic kidney damage after subtotal cystectomy. Maximal contraction of bladder strips to electrical field stimulation, as well as activation with carbachol, phenylephrine, and KCl, were lower in old than in young animals at 26 weeks after subtotal cystectomy. Immunostaining with proliferating cell nuclear antigen and Von Willebrand factor revealed delayed and/or diminished proliferative and angiogenic responses, respectively, in old animals. These results confirm prior work and suggest that multiple mechanisms may contribute to an age-related decline in the regenerative capacity of the bladder.

Cell-seeded tubularized scaffolds for reconstruction of long urethral defects: a preclinical study.

BACKGROUND: The treatment options for patients requiring repair of a long segment of the urethra are limited by the availability of autologous tissues. We previously reported that acellular collagen-based tubularized constructs seeded with cells are able to repair small urethral defects in a rabbit model. OBJECTIVE: We explored the feasibility of engineering clinically relevant long urethras for surgical reconstruction in a canine preclinical model. DESIGN, SETTING, AND PARTICIPANTS: Autologous bladder epithelial and smooth muscle cells from 15 male dogs were grown and seeded onto preconfigured collagen-based tubular matrices (6 cm in length). The perineal urethral segment was removed in 21 male dogs. Urethroplasties were performed with tubularized collagen scaffolds seeded with cells in 15 animals. Tubularized constructs without cells were implanted in six animals. Serial urethrography and three-dimensional computed tomography (CT) scans were performed pre- and postoperatively at 1, 3, 6, and 12 mo. The animals were euthanized at their predetermined time points (three animals at 1 mo, and four at 3, 6, and 12 mo) for analyses. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Statistical analysis of CT imaging and histology was not needed. RESULTS AND LIMITATIONS: CT urethrograms showed wide-caliber urethras without strictures in animals implanted with cell-seeded matrices. The urethral segments replaced with acellular scaffolds collapsed. Gross examination of the urethral implants seeded with cells showed normal-appearing tissue without evidence of fibrosis. Histologically, an epithelial cell layer surrounded by muscle fiber bundles was observed on the cell-seeded constructs, and cellular organization increased over time. The epithelial and smooth muscle phenotypes were confirmed using antibodies to pancytokeratins AE1/AE3 and smooth muscle-specific desmin. Formation of an epithelial cell layer occurred in the unseeded constructs, but few muscle fibers formed. CONCLUSIONS: Cell-seeded tubularized collagen scaffolds can be used to repair long urethral defects, whereas scaffolds without cells lead to poor tissue development and strictures. This study demonstrates that long tissue-engineered tubularized urethral segments may be used for urethroplasty in patients.

Production and implantation of renal extracellular matrix scaffolds from porcine kidneys as a platform for renal bioengineering investigations.

BACKGROUND: It is important to identify new sources of transplantable organs because of the critical shortage of donor organs. Tissue engineering holds the potential to address this issue through the implementation of decellularization-recellularization technology. OBJECTIVE: To produce and examine acellular renal extracellular matrix (ECM) scaffolds as a platform for kidney bioengineering. METHODS: Porcine kidneys were decellularized with distilled water and sodium dodecyl sulfate-based solution. After rinsing with buffer solution to remove the sodium dodecyl sulfate, the so-obtained renal ECM scaffolds were processed for vascular imaging, histology, and cell seeding to investigate the vascular patency, degree of decellularization, and scaffold biocompatibility in vitro. Four whole renal scaffolds were implanted in pigs to assess whether these constructs would sustain normal blood pressure and to determine their biocompatibility in vivo. Pigs were sacrificed after 2 weeks and the explanted scaffolds were processed for histology. RESULTS: Renal ECM scaffolds were successfully produced from porcine kidneys. Scaffolds retained their essential ECM architecture and an intact vascular tree and allowed cell growth. On implantation, unseeded scaffolds were easily reperfused, sustained blood pressure, and were tolerated throughout the study period. No blood extravasation occurred. Pathology of explanted scaffolds showed maintenance of renal ultrastructure. Presence of inflammatory cells in the pericapsular region and complete thrombosis of the vascular tree were evident. CONCLUSIONS: Our investigations show that pig kidneys can be successfully decellularized to produce renal ECM scaffolds. These scaffolds maintain their basic components, are biocompatible, and show intact, though thrombosed, vasculature.

Impact of partial urethral obstruction on bladder function: time-dependent changes and functional correlates of altered expression of Ca²âº signaling regulators.

In animal models of partial urethral obstruction (PUO), altered smooth muscle function/contractility may be linked to changes in molecules that regulate calcium signaling/sensitization. PUO was created in male rats, and urodynamic studies were conducted 2 and 6 wk post-PUO. Cystometric recordings were analyzed for the presence or absence of nonvoiding contractions [i.e., detrusor overactivity (DO)]. RT-PCR and Western blots were performed on a subpopulation of rats to study the relationship between the expression of RhoA, L-type Ca(2+) channels, Rho kinase-1, Rho kinase-2, inositol 1,4,5-trisphosphate, ryanodine receptor, sarco(endo)plasmic reticulum Ca(2+)-ATPase 2 and protein kinase C (PKC)-potentiated phosphatase inhibitor of 17 kDa, and urodynamic findings in the same animal. Animals displayed DO at 2 (38%) and 6 wk (43%) post-PUO, increases were seen in in vivo pressures at 2 wk, and residual volume at 6 wk. Statistical analysis of RT-PCR and Western blot data at 2 wk, during the compensatory phase of detrusor hypertrophy, documented that expression of molecules that regulate calcium signaling and sensitization was consistently lower in obstructed rats without DO than those with DO or control rats. Among rats with DO at 2 wk, linear regression analysis revealed positive correlations between in vivo pressures and protein and mRNA expression of several regulatory molecules. At 6 wk, in the presence of overt signs of bladder decompensation, no clear or consistent alterations in expression of these same targets were observed at the protein level. These data extend prior work to suggest that molecular profiling of key regulatory molecules during the progression of PUO-mediated bladder dysfunction may shed new light on potential biomarkers and/or therapeutic targets.

Muscle precursor cells for the restoration of irreversibly damaged sphincter function.

Multiple modalities, including injectable bulking agents and surgery, have been used to treat stress urinary incontinence. However, none of these methods is able to fully restore normal striated sphincter muscle function. In this study, we explored the possibility of achieving functional recovery of the urinary sphincter muscle using autologous muscle precursor cells (MPCs) as an injectable, cell-based therapy. A canine model of striated urinary sphincter insufficiency was created by microsurgically removing part of the sphincter muscle in 24 dogs. Autologous MPCs were obtained, expanded in culture, and injected into the damaged sphincter muscles of 12 animals. The animals were followed for up to 6 months after injection, and urodynamic studies, functional organ bath studies, ultrastructural and histological examinations were performed. Animals receiving MPC injections demonstrated sphincter pressures of approximately 80% of normal values, while the pressures in the control animals without cells dropped and remained at 20% of normal values. Histological analysis indicated that the implanted cells survived and formed tissue, including new innervated muscle fibers, within the injected region of the sphincter. These results indicate that autologous muscle precursor cells may be able to restore otherwise irreversibly damaged urinary sphincter function clinically.

Is tissue engineering and biomaterials the future for lower urinary tract dysfunction (LUTD)/pelvic organ prolapse (POP)?

The fields of tissue engineering and regenerative medicine have seen major advances over the span of the past two decades, with biomaterials playing a central role. Although the term "regenerative medicine" has been applied to encompass most fields of medicine, in fact urology has been one of the most progressive. Many urological applications have been investigated over the past decades, with the culmination of these technologies in the introduction of the first laboratory-produced organ to be placed in a human body.1 With the quality of life issues associated with urinary incontinence, there is a strong driver to identify and introduce new technologies and the potential exists for further major advancements from regenerative medicine approaches using biomaterials, cells or a combination of both. A central question is why use biomaterials? The answer rests on the need to make up for inadequate or lack of autologous tissue, to decrease morbidity and to improve long-term efficacy. Thus, the ideal biomaterial needs to meet the following criteria: (1) Provide mechanical and structural support, (2) Maintain compliance and be biocompatible with surrounding tissues, and (3) Be "fit for purpose" by meeting specific application needs ranging from static support to bioactive cell signaling. In essence, this represents a wide range of biomaterials with a spectrum of potential applications, from use as a supportive or bulking implant alone, to implanted biomaterials that promote integration and eventual replacement by infiltrating host cells, or scaffolds pre-seeded with cells prior to implant. In this review we shall discuss the structural versus the integrative uses of biomaterials by referring to two key areas in urology of (1) pelvic organ support for prolapse and stress urinary incontinence, and (2) bladder replacement/augmentation.

Impaired bladder function in aging male rats.

PURPOSE: The prevalence of bladder dysfunctions increases with age. In humans it is difficult to separate changes related to exogenous factors from those directly related to the aging process. Some confounding variables can be avoided by studying age related changes in an animal model. We evaluated the impact of age on bladder function in vivo and in vitro, and characterized the corresponding morphological changes. MATERIALS AND METHODS: Young (4 to 6 months old) and old (older than 28 to 30 months) male Fischer/Brown Norway rats were used in the study. Cystometric studies were done in conscious, freely moving rats. After cystometry tissue strips from the bladder body were used in in vitro studies of muscarinic receptor activation and electrical field stimulation, and histological examination. RESULTS: Old rats had higher bladder weight than young rats but the bladder-to-body weight ratio did not change. We noted significant age related differences in 8 of 10 cystometric parameters. Old rats had increased bladder capacity, post-void residual volume, micturition volume and frequency, baseline and intermicturition pressure, and spontaneous activity but decreased micturition pressure. Bladder strip responses to carbachol and electrical field stimulation were significantly lower in old than in young rats. Histological examination revealed urothelial thinning, lower muscle mass and higher collagen content in the bladders of old vs young rats. CONCLUSIONS: Physiological aging alters bladder function in male rats even when external factors remain constant. Thus, in old rats bladder capacity, post-void residual urine and spontaneous activity are higher, and responses to muscarinic receptor stimulation and electrical field stimulation are lower than in young rats. Such changes correspond to findings in aging human bladders, supporting the view that the Fischer/Brown Norway rat is a useful model in which to study age related bladder function changes.

Early stages of in situ bladder regeneration in a rodent model.

Surgical removal of approximately 70% of the bladder (subtotal cystectomy [STC]) was used as a model system to gain insight into the normal regenerative process in adult mammals in vivo. Female F344 rats underwent STC, and at 2, 4, and 8 weeks post-STC, bladder regeneration was monitored via microcomputed tomography scans, urodynamic (bladder function studies) pharmacologic studies, and immunohistochemistry. Computed tomography imaging revealed a time-dependent increase in bladder size at 2, 4, and 8 weeks post-STC, which positively correlated with restoration of bladder function. Bladders emptied completely at all time points studied. The maximal contractile response to pharmacological activation and electrical field stimulation increased over time in isolated tissue strips from regenerating bladders, but remained lower at all time points compared with strips from age-matched control bladders. Immunostaining of the bladder wall of STC rats suggested a role for progenitor cells and cellular proliferation in the regenerative response. Immunostaining and the presence of electrical field stimulation-induced contractile responses verified innervation of the regenerated bladder. These initial studies establish the utility of the present model system for studying de novo tissue regeneration in vivo and may provide guidance with respect to optimization of intrinsic regenerative capacity for clinical applications.

Alterations in bladder function associated with urothelial defects in uroplakin II and IIIa knockout mice.

AIMS: The effects of deleting genes encoding uroplakins II (UPII) and III (UPIIIa) on mouse bladder physiology/dysfunction were studied in male and female wild type and knockout (KO) mice. METHODS: UPII, UPIIIa, and WT mice were catheterized using previously described techniques. Continuous cystometry was conducted in conscious, freely moving animals. Bladder strips were harvested after animal sacrifice and pharmacological studies and EFS were conducted in an organ chamber. Histological studies were also carried on with H&E staining to identify differences among the three mouse types. RESULTS: These studies have revealed numerous alterations, some of which were apparently gender-specific. Nonvoiding contractions were common in both UPII and UPIIIa KO mice, although more severe in the former. In particular, the increased bladder capacity, micturition pressure and demonstrable nonvoiding contractions observed in the male UPII KO's, were reminiscent of an obstruction-like syndrome accompanied by evidence of emerging bladder decompensation, as reflected by an increased residual volume. Pharmacological studies revealed a modest, gender-specific reduction in sensitivity of isolated detrusor strips from UPII KO female mice to carbachol-induced contractions. A similar reduction was observed in UPIIIa KO female mice. Histological investigation showed urothelial hyperplasia in both UPII KO and UPIIIa KO mice, although again, apparently more severe in the former. CONCLUSIONS: These results confirm and extend previous work to indicate that urothelial defects due to uroplakin deficiency are associated with significant alterations in bladder function and further highlight the importance of the urothelium to bladder physiology/dysfunction.