Assessing sociodemographic and regional disparities in Oncotype DX Genomic Prostate Score uptake.

BACKGROUND: The Oncotype DX Genomic Prostate Score (ODX-GPS) is a gene expression assay that predicts disease aggressiveness. The objective of this study was to identify sociodemographic and regional factors associated with ODX-GPS uptake. METHODS: Data from Surveillance Epidemiology and End Results registries on men with localized prostate cancer with a Gleason score of 3 + 3 or 3 + 4, PSA ≤20 ng/mL, and stage T1c to T2c disease from 2013 through 2017 were linked with ODX-GPS data. Census-tract level neighborhood socioeconomic status (nSES) quintiles were constructed using a composite socioeconomic score. Multivariable logistic regression was used to estimate the associations of ODX-GPS uptake with age at diagnosis, race and ethnicity, nSES, geographic region, insurance type, and marital status, accounting for National Comprehensive Cancer Network risk group, year of diagnosis, and clustering by census tract. RESULTS: Among 111,434 eligible men, 5.5% had ODX-GPS test uptake. Of these, 78.3% were non-Hispanic White, 9.6% were Black, 6.7% were Hispanic, and 3.6% were Asian American. Black men had the lowest odds of ODX-GPS uptake (odds ratio, 0.70; 95% confidence interval [CI], 0.63-0.76). Those in the highest versus lowest quintile of nSES were 1.64 times more likely (95% CI, 1.38-2.94) to have ODX-GPS uptake. The odds of ODX-GPS uptake were statistically significantly higher among men residing in the Northeast, West, and Midwest compared to the South. CONCLUSIONS: Disparities in ODX-GPS uptake by race, ethnicity, nSES, and geographical region were identified. Concerted efforts should be made to ensure that this clinical test is equitably available.

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.

Positive outcomes with first onabotulinumtoxinA treatment persist in the long term with repeat treatments in patients with neurogenic detrusor overactivity.

OBJECTIVE: To examine whether response to first treatment with onabotulinumtoxinA is predictive of long-term treatment outcome in patients with neurogenic detrusor overactivity (NDO). PATIENTS AND METHODS: Patients with NDO who were enrolled in a 3-year extension study (after a 52-week phase III study) received onabotulinumtoxinA 'as needed', based on fulfilment of prespecified retreatment criteria. This post hoc analysis included patients who received only the 200-U dose during the phase III and extension studies. Data on mean percent reduction from baseline in urinary incontinence (UI) episodes at week 6 after the first treatment were analysed, and the patients were stratified into three response groups: <50% (group 1; n = 33), 50-74% (group 2; n = 23), and 75-100% (group 3; n = 139). The following were assessed: change from baseline in mean percent UI reduction; proportions of patients who achieved ≥50% and 100% UI reduction after each subsequent treatment, and patients who achieved ≥50% UI reduction after all subsequent treatments; change from baseline in Incontinence Quality of Life (I-QOL) total summary score; and the proportion of patients who achieved or exceeded the minimally important difference (MID; +11 points) in I-QOL score. Adverse events (AEs) were also assessed. RESULTS: The majority of the patients (83.1%; 162/195) experienced a ≥50% UI reduction after onabotulinumtoxinA treatment 1. Baseline characteristics were largely similar across the groups. After treatment 1, the mean percent reduction in UI remained consistent in subsequent treatments 2-6 for patients in response group 2 (range: 64.5-83.5%) and group 3 (range: 79.4-88.0%), but increased for those in the low response group (range: 36.3-60.3%). After treatment 1, the proportion of patients who achieved ≥50% reduction in UI episodes was consistent with subsequent treatments 2-6 in group 2 (range: 75.0-100%) and group 3 (range: 87.3-97.1%), but increased in the low response group (range: 48.3-72.7%). Even among those who achieved a low response after treatment 1, 37.9% of patients achieved ≥50% UI reduction in all subsequent treatments. Improvements in I-QOL scores in groups 2 and 3 were consistently 2-3 times the MID. In the low response group, at least 50% of the patients achieved or exceeded the MID with treatments 2-6. AEs were similar across all response groups and consistent across repeated treatments. CONCLUSION: Patients with NDO with a ≥50% UI reduction after their first onabotulinumtoxinA treatment continued to experience consistent improvements in UI and quality of life with subsequent treatments over the duration of 4 years. A <50% UI reduction after first treatment did not necessarily predict low response with subsequent treatments. Thus, these results underscore the importance of attempting at least a second treatment with onabotulinumtoxinA before deeming patients unsuitable for onabotulinumtoxinA therapy.

Potential Use of Autologous Renal Cells from Diseased Kidneys for the Treatment of Renal Failure.

Chronic kidney disease (CKD) occurs when certain conditions cause the kidneys to gradually lose function. For patients with CKD, renal transplantation is the only treatment option that restores kidney function. In this study, we evaluated primary renal cells obtained from diseased kidneys to determine whether their normal phenotypic and functional characteristics are retained, and could be used for cell therapy. Primary renal cells isolated from both normal kidneys (NK) and diseased kidneys (CKD) showed similar phenotypic characteristics and growth kinetics. The expression levels of renal tubular cell markers, Aquaporin-1 and E-Cadherin, and podocyte-specific markers, WT-1 and Nephrin, were similar in both NK and CKD kidney derived cells. Using fluorescence- activated cell sorting (FACS), specific renal cell populations were identified and included proximal tubular cells (83.1% from NK and 80.3% from CKD kidneys); distal tubular cells (11.03% from NK and 10.9% from CKD kidneys); and podocytes (1.91% from NK and 1.78% from CKD kidneys). Ultra-structural analysis using scanning electron microscopy (SEM) revealed microvilli on the apical surface of cultured cells from NK and CKD samples. Moreover, transmission electron microscopy (TEM) analysis showed a similar organization of tight junctions, desmosomes, and other intracellular structures. The Na+ uptake characteristics of NK and CKD derived renal cells were also similar (24.4 mmol/L and 25 mmol/L, respectively) and no significant differences were observed in the protein uptake and transport characteristics of these two cell isolates. These results show that primary renal cells derived from diseased kidneys such as CKD have similar structural and functional characteristics to their counterparts from a normal healthy kidney (NK) when grown in vitro. This study suggests that cells derived from diseased kidney may be used as an autologous cell source for renal cell therapy, particularly in patients with CKD or end-stage renal disease (ESRD).

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.

Hemostatic properties and the role of cell receptor recognition in human hair keratin protein hydrogels.

Driven by new discoveries in stem-cell biology and regenerative medicine, there is broad interest in biomaterials that go beyond basic interactions with cells and tissues to actively direct and sustain cellular behavior. Keratin biomaterials have the potential to achieve these goals but have been inadequately described in terms of composition, structure, and cell-instructive characteristics. In this manuscript we describe and characterize a keratin-based biomaterial, demonstrate self-assembly of cross-linked hydrogels, investigate a cell-specific interaction that is dependent on the hydrogel structure and mediated by specific biomaterial-receptor interactions, and show one potential medical application that relies on receptor binding - the ability to achieve hemostasis in a lethal liver injury model. Keratin biomaterials represent a significant advance in biotechnology as they combine the compatibility of natural materials with the chemical flexibility of synthetic materials. These characteristics allow for a system that can be formulated into several varieties of cell-instructive biomaterials with potential uses in tissue engineering, regenerative medicine, drug and cell delivery, and trauma.

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.

Cell therapy with human renal cell cultures containing erythropoietin-positive cells improves chronic kidney injury.

New therapeutic strategies for chronic kidney disease (CKD) are necessary to offset the rising incidence of CKD and donor shortage. Erythropoietin (EPO), a cytokine produced by fibroblast-like cells in the kidney, has recently emerged as a renoprotective factor with anti-inflammatory, antioxidant properties. This study (a) determined whether human renal cultures (human primary kidney cells [hPKC]) can be enriched in EPO-positive cells (hPKC(F+)) by using magnetic-bead sorting; (b) characterized hPKC(F+) following cell separation; and (c) established that intrarenal delivery of enriched hPKC(F+) cells would be more beneficial in treatment of renal injury, inflammation, and oxidative stress than unsorted hPKC cultures in a chronic kidney injury model. Fluorescence-activated cell sorting analysis revealed higher expression of EPO (36%) and CD73 (27%) in hPKC(F+) as compared with hPKC. After induction of renal injury, intrarenal delivery of hPKC(F+) or hPKC significantly reduced serum creatinine, interstitial fibrosis in the medulla, and abundance of CD68-positive cells in the cortex and medulla (p < .05). However, only hPKC(F+) attenuated interstitial fibrosis in the renal cortex and decreased urinary albumin (3.5-fold) and urinary tubular injury marker kidney injury molecule 1 (16-fold). hPKC(F+) also significantly reduced levels of renal cortical monocyte chemotactic protein 1 (1.8-fold) and oxidative DNA marker 8-hydroxy-deoxyguanosine (8-OHdG) (2.4-fold). After 12 weeks, we detected few injected cells, which were localized mostly to the cortical interstitium. Although cell therapy with either hPKC(F+) or hPKC improved renal function, the hPKC(F+) subpopulation provides greater renoprotection, perhaps through attenuation of inflammation and oxidative stress. We conclude that hPKC(F+) may be used as components of cell-based therapies for degenerative kidney diseases.

Ischemia/reperfusion-induced renal failure in rats as a model for evaluating cell therapies.

Chronic renal failure is a devastating disease that leads to a multitude of complications. Cell therapy has emerged as a potential treatment modality for renal failure. However, efficacy testing on systemic renal function has been challenging due to the limited availability of reliable models that are fully characterized. In this study, we investigated the possibility of using renal ischemia/reperfusion (I/R) injury as a viable model for testing cell therapies. We examined functional and pathological changes in rat kidneys that were exposed to different ischemia times. Male Lewis rats were divided into five groups. Renal failure was induced by clamping both renal pedicles for combinations of 60, 75, and 90 min, followed by reperfusion. Age-matched healthy rats served as controls. Blood was collected at regular intervals for serum chemistry, and kidneys were harvested at the same intervals for histomorphological assessment. Serum creatinine levels of the animals with I/R injury increased significantly after 3 days and returned to normal levels at 4 weeks. Histologically, kidney tissue showed progressive glomerular and tubular deterioration with varying degrees of fibrosis. Animals exposed to 75- and 90-min ischemia combination times consistently generated more severe injury than the 60-min ischemia period. However, these groups resulted in a high mortality rate. A model in which one kidney is exposed to a shorter ischemia time (60 or 90 min) resulted in sustained renal damage with a lower mortality rate. This study shows that kidneys exposed to I/R result in renal tissue damage as well as decreased renal function. This model can be used to study both the short-term and longer-term effects of kidney disease by varying the length of the ischemic time. In particular, the use of longer ischemic times (75 and 90 min) could be used to study new therapies for acute renal disease, whereas shorter ischemic times (60 min) could be used to study therapies for chronic renal insufficiency.

Controlled regulation of erythropoietin by primary cultured renal cells for renal failure induced anemia.

PURPOSE: Renal failure induced anemia develops as a result of inadequate production of erythropoietin, which is the primary regulator of red blood cell production. We previously noted that culture expanded primary renal cells stably express erythropoietin and suggested that these cells may be used as a potential treatment for renal failure induced anemia. We investigated whether these cells are able to regulate erythropoietin expression in a controlled manner under different oxygen and environmental conditions. MATERIALS AND METHODS: Primary rat renal cells were exposed to different hypoxic (0.1% to 1% O(2)) and normoxic environments. Erythropoietin expression was assessed using reverse transcriptase-polymerase chain reaction. Erythropoietin production was measured in culture medium using Meso Scale Discovery® assays. Results were plotted to compare different levels of production to the control. RESULTS: Cultured renal cells expressed high levels of erythropoietin under hypoxia for up to 24 hours with a gradual decrease thereafter. However, erythropoietin expression was decreased when cells were switched from a hypoxic to a normoxic environment within the initial 24 hours. This indicated that cultured renal cells have the capacity to sense environmental oxygen tension and regulate erythropoietin expression accordingly. In addition, erythropoietin release in medium followed a pattern similar to that of gene expression under normoxic and hypoxic conditions. CONCLUSIONS: These findings indicate that primary renal cells have the ability to regulate erythropoietin gene expression and release through environment dependent mechanisms. This also suggests that with further study the possibility exists of developing these cells as a potential method to treat renal failure induced anemia.