Microarray analysis of bladder smooth muscle from patients with myelomeningocele

Integrated omics analysis unveils a DNA damage response to neurogenic injury

Spinal cord injury (SCI) evokes profound bladder dysfunction. Current treatments are limited by a lack of molecular data to inform novel therapeutic avenues. Previously, we showed systemic inosine treatment improved bladder function following SCI in rats. Here, we applied multi-omics analysis to explore molecular alterations in the bladder and their sensitivity to inosine following SCI. Canonical pathways regulated by SCI included those associated with protein synthesis, neuroplasticity, wound healing, and neurotransmitter degradation. Upstream regulator analysis identified MYC as a key regulator, whereas causal network analysis predicted multiple regulators of DNA damage response signaling following injury, including PARP-1. Staining for both DNA damage (γH2AX) and PARP activity (poly-ADP-ribose) markers in the bladder was increased following SCI, and attenuated in inosine-treated tissues. Proteomics analysis suggested that SCI induced changes in protein synthesis-, neuroplasticity-, and oxidative stress-associated pathways, a subset of which were shown in transcriptomics data to be inosine-sensitive. These findings provide novel insights into the molecular landscape of the bladder following SCI, and highlight a potential role for PARP inhibition to treat neurogenic bladder dysfunction.

The association of urinary BDNF, ATP, and MMP-2 with bladder compliance in children with myelodysplasia

AIM

The purpose of our study was to evaluate the relationship of urinary brain-derived neurotrophic factor (BDNF), adenosine triphosphate (ATP), matrix metallopreteinase-2 (MMP-2) with urodynamic findings and upper urinary tract deterioration (UUTD) in children with myelodysplasia.

MATERIALS AND METHODS

Children with myelodysplasia evaluated in outpatient clinic between 2022 and 2023 were included. All patients underwent urinary ultrasonography, voiding cystourethrography, urodynamics, and DMSA scintigraphy. Urine samples were collected before urodynamics. Control urine was collected from 10 healthy children. Urinary biomarker values of patients and controls were compared, and subgroup analysis was performed.

RESULTS

The median age of 40 children (26 girls) included in the study was 108 (8-216) months, and the control group (six girls) was 120 (60-154) (p = 0.981). Urinary BDNF, MMP-2, and ATP were found to be significantly higher in children with myelodysplasia compared to the control (p = 0.007, p = 0.027, p = 0.014, respectively). The three biomarker values were similar in children with bladder compliance below or above 10 cmH2O/mL (p = 0.750, p = 0.844, p = 0.575). No difference was found in terms of UUTD in all three biomarkers (p = 0.387, p = 0.892, p = 0.705). A negative correlation was found between urinary ATP and compliance (p < 0.05).

CONCLUSION

In this study, all three biomarkers were found to be higher in children with myelodysplasia than in controls. There was a negative correlation between urinary ATP and compliance. Urinary biomarkers may contribute the follow-up of children with neurogenic lower urinary tract deterioration in future with their noninvasive features. However, the lack of standardization and the inability to reliably predict risky groups are important shortcomings of urinary biomarkers.

Neurogenic Lower Urinary Tract Dysfunction in Spinal Dysraphism: Morphological and Molecular Evidence in Children

Spinal dysraphism, most commonly myelomeningocele, is the typical cause of a neurogenic lower urinary tract dysfunction (NLUTD) in childhood. The structural changes in the bladder wall in spinal dysraphism already occur in the fetal period and affect all bladder wall compartments. The progressive decrease in smooth muscle and the gradual increase in fibrosis in the detrusor, the impairment of the barrier function of the urothelium, and the global decrease in nerve density, lead to severe functional impairment characterized by reduced compliance and increased elastic modulus. Children present a particular challenge, as their diseases and capabilities evolve with age. An increased understanding of the signaling pathways involved in lower urinary tract development and function could also fill an important knowledge gap at the interface between basic science and clinical implications, leading to new opportunities for prenatal screening, diagnosis, and therapy. In this review, we aim to summarize the evidence on structural, functional, and molecular changes in the NLUTD bladder in children with spinal dysraphism and discuss possible strategies for improved management and for the development of new therapeutic approaches for affected children.

Improved contractile potential in detrusor microtissues from pediatric patients with end stage lower urinary tract dysfunction

Autologous cell-based tissue engineering has been proposed as a treatment option for end stage lower urinary tract dysfunction (ESLUTD). However, it is generally accepted that cells isolated from patient bladders retain the pathological properties of their tissue of origin and therefore need to be improved before they can serve as a cell source for tissue engineering applications. We hypothesize that human three-dimensional (3D) microtissues of detrusor smooth muscle cells (SMCs) are valuable ex vivo disease models and potent building blocks for bladder tissue engineering. Detrusor SMCs isolated from bladder wall biopsies of pediatric ESLUTD patients and healthy controls were expanded and cultured into 3D microtissues. Gene and protein analyses were performed to explore the effect of microtissue formation on SMC viability, contractile potential, bladder wall specific extracellular matrix (ECM) composition and mediators of ECM remodeling. Through microtissue formation, remodeling and intensified cell-cell interactions, the ESLUTD SMCs lost their characteristic disease phenotype. These microtissues exhibited similar patterns of smooth muscle related contractile proteins and essential bladder wall-specific ECM components as microtissues from healthy control subjects. Thus, the presented data suggest improved contractile potential and ECM composition in detrusor SMC microtissues from pediatric ESLUTD patients. These findings are of great relevance, as 3D detrusor SMC microtissues might be an appropriate cell source for autologous cell-based bladder tissue engineering.

Deletion of Mechanosensory β1-integrin From Bladder Smooth Muscle Results in Voiding Dysfunction and Tissue Remodeling

The bladder undergoes large shape changes as it fills and empties and experiences complex mechanical forces. These forces become abnormal in diseases of the lower urinary tract such as overactive bladder, neurogenic bladder, and urinary retention. As the primary mechanosensors linking the actin cytoskeleton to the extracellular matrix (ECM), integrins are likely to play vital roles in maintaining bladder smooth muscle (BSM) homeostasis. In a tamoxifen-inducible smooth muscle conditional knockout of β1-integrin, there was concomitant loss of α1- and α3-integrins from BSM and upregulation of αV- and β3-integrins. Masson's staining showed a reduction in smooth muscle with an increase in collagenous ECM. Functionally, mice exhibited a changing pattern of urination by voiding spot assay up to 8 wk after tamoxifen. By 8 wk, there was increased frequency with reductions in voided volume, consistent with overactivity. Cystometrograms confirmed that there was a significant reduction in intercontractile interval with reduced maximal bladder pressure. Muscle strip myography revealed a loss of contraction force in response to electrical field stimulation, that was entirely due to the loss of muscarinic contractility. Quantitative western blotting showed a loss of M3 receptor and no change in P2X1. qPCR on ECM and interstitial genes revealed loss of Ntpd2, a marker of an interstitial cell subpopulation; and an upregulation of S100A4, which is often associated with fibroblasts. Collectively, the data show that the loss of appropriate mechanosensation through integrins results in cellular and extracellular remodeling, and concomitant bladder dysfunction that resembles lower urinary tract symptoms seen in older people.

Ultrasound shear wave elastography cannot discriminate between low- and high-pressure neurogenic bladders

BACKGROUND

Patients with neurogenic bladders are monitored with renal bladder ultrasounds and video urodynamics studies (VUDS) to assess upper urinary tract injury. Ultrasound shear wave elastography (US-SWE) can assess tissue stiffness. If bladder compliance is affected by bladder wall fibrosis and stiffening, then high-pressure bladders may be detectable by US-SWE therefore reducing the need for VUDS in some patients.

OBJECTIVE

To determine if US-SWE can differentiate between low- and high-pressure bladders and hence be used for noninvasive assessment of neurogenic bladder in children.

STUDY DESIGN

Prospective study of patients with neurogenic bladder undergoing clinically indicated VUDS between February and July of 2017. During VUDS, bladder wall US-SWE was measured at different filling percentages of estimated bladder capacity (EBC). The bladders were divided into cohorts according to the detrusor muscle pressure (P_det) reached at the maximum bladder capacity: normal (1 to <15 cmH₂O) and abnormal (≥15 cmH₂O) pressure. T-test was used to compare elastography values at different bladder volumes and P_det; (statistical significance set at p < 0.05).

RESULTS

30/31 enrolled children completed the protocol. With an empty bladder, as well as at all other bladder volumes, no relationship was observed between P_det and mean SWE of the anterior or posterior bladder wall. At maximum bladder capacity, there was no difference between mean SWE values of the anterior or posterior bladder walls in those with normal pressure, 2.97 m/s (SD ± 0.82) and 1.96 m/s (SD ± 0.75), compared to those with abnormal pressures 3.08 m/s (SD ± 0.84) and 2.39 m/s (SD ± 0.96), p = 0.75 and p = 0.2, respectively.

DISCUSSION

We found no difference between SWE values of either the anterior or posterior bladder wall in neurogenic bladders with normal and abnormal filling pressures measured during VUDS. Our study differs from previously reported studies with more positive results in that our cut-off for abnormal bladder pressure was (P_det ≥15 cmH₂O). This is lower than the more commonly used leak point pressure of 40 cmH₂O because our practice is to intervene earlier. Moreover, SWE would be most useful if it can identify changes before the bladder has reached such severe conditions, to allow for early intervention. Additional differences between ours and other studies include US manufacturer and younger age of the participating children.

CONCLUSIONS

US-SWE, while feasible, was not able to discriminate between low- and high-pressure bladders. Moreover, US-SWE did not show significant correlation with the current gold standard, VUDS.

Biomaterials assisted reconstructive urology: The pursuit of an implantable bioengineered neo-urinary bladder

Urinary bladder is a dynamic organ performing complex physiological activities. Together with ureters and urethra, it forms the lower urinary tract that facilitates urine collection, low-pressure storage, and volitional voiding. However, pathological disorders are often liable to cause irreversible damage and compromise the normal functionality of the bladder, necessitating surgical intervention for a reconstructive procedure. Non-urinary autologous grafts, primarily derived from gastrointestinal tract, have long been the gold standard in clinics to augment or to replace the diseased bladder tissue. Unfortunately, such treatment strategy is commonly associated with several clinical complications. In absence of an optimal autologous therapy, a biomaterial based bioengineered platform is an attractive prospect revolutionizing the modern urology. Predictably, extensive investigative research has been carried out in pursuit of better urological biomaterials, that overcome the limitations of conventional gastrointestinal graft. Against the above backdrop, this review aims to provide a comprehensive and one-stop update on different biomaterial-based strategies that have been proposed and explored over the past 60 years to restore the dynamic function of the otherwise dysfunctional bladder tissue. Broadly, two unique perspectives of bladder tissue engineering and total alloplastic bladder replacement are critically discussed in terms of their status and progress. While the former is pivoted on scaffold mediated regenerative medicine; in contrast, the latter is directed towards the development of a biostable bladder prosthesis. Together, these routes share a common aspiration of designing and creating a functional equivalent of the bladder wall, albeit, using fundamentally different aspects of biocompatibility and clinical needs. Therefore, an attempt has been made to systematically analyze and summarize the evolution of various classes as well as generations of polymeric biomaterials in urology. Considerable emphasis has been laid on explaining the bioengineering methodologies, pre-clinical and clinical outcomes. Some of the unaddressed challenges, including vascularization, innervation, hollow 3D prototype fabrication and urinary encrustation, have been highlighted that currently delay the successful commercial translation. More importantly, the rapidly evolving and expanding concepts of bioelectronic medicine are discussed to inspire future research efforts towards the further advancement of the field. At the closure, crucial insights are provided to forge the biomaterial assisted reconstruction as a long-term therapeutic strategy in urological practice for patients' care.

Factors predicting the success of intradetrusor onabotulinum toxin-A treatment in children with neurogenic bladders due to myelomeningocele: The outcomes of a large cohort

OBJECTIVE

This study aimed to determine the effectiveness of intradetrusor injections of onabotulinum toxin-A (BoNT-A) in pediatric patients with neurogenic bladders (NB) due to myelomeningocele (MMC). The factors predicting success were also evaluated.

STUDY DESIGN

We retrospectively identified 62 patients with NB due to MMC who underwent intravesical BoNT-A injection (100-300 U) between May 2013 and December 2018. Indications for BoNT-A injection were according to the European Association of Urology guidelines and included children for whom clean intermittent catheterization (CIC) and anticholinergic therapy had failed. Children who had previous bladder surgery or anti-reflux operations, coagulation disorders, myasthenia gravis, and non-neurogenic bladders were excluded. Twenty-one patients had accompanying vesicoureteral reflux (VUR). Preoperative and postoperative urodynamic parameters, clinical success, and VUR grades for all patients were recorded. Clinical success was defined as 4 h of dryness or bladder control between CICs. Logistic regression analysis was performed to evaluate the factors affecting treatment success.

RESULTS

The mean age of the children was 9 ± 3.36 years. The mean follow-up was 28.5 ± 12.2 months. Clinical success was achieved in 64.5% (n: 40) of the patients. The mean maximal cystometric capacity increased from 172.4 ± 45.6 mL to 236.3 ± 67.2 mL. The mean bladder compliance increased from 14.8 ± 8.1 mL/cm H₂O to 19.3 ± 7.4 mL/cm H₂O, and the mean maximal detrusor pressure decreased from 56.7 ± 18.8 cm H₂O to 36.6 ± 10.1 cm H₂O. Urodynamic parameters did not improve in patients with hypocompliant (fibrotic) bladders. In patients with accompanying VUR, reflux was completely resolved in 53.8% (n: 14) of the ureters, improved in 26.9% (n: 7) of the ureters, and remained unchanged in 19.2% (n: 5) of the ureters after subureteral injection.

CONCLUSION

Intradetrusor BoNT-A injections provide excellent outcomes in children with NB refractory to conservative treatments. Poor responses were observed in patients who had low-compliant bladders without detrusor overactivity.

Non-invasive markers in the management of pediatric neurogenic bladder over the last two decades - A review

Neurogenic bladder (NB) is one of the most challenging problems in nephro-urological management in pediatrics. It is an important risk factor of secondary upper urinary tract damage. A complete clinical evaluation is necessary and requires life-long extensive medical attention including invasive procedures that affect patients' quality of life. Potential non-invasive biomarkers would be desirable, especially in the pediatric population. The aim of this review was to analyze two decades of data regarding potential non-invasive biomarkers in the assessment and follow-up of children with NB. This paper summarizes and appraises the knowledge about both biochemical and imaging-based markers in 3 aspects: markers of urinary tract infections (UTIs), bladder and renal function, and this paper looks at their prospective application in everyday clinical care.

Detrusor bioengineering using a cell-enriched compressed collagen hydrogel

OBJECTIVE

The gold standard for bladder regeneration in end-stage bladder disease is the use of intestinal tissue, which is however associated with significant long-term complications. Our study aims to bioengineer functional detrusor muscle combining bladder smooth muscle cells (SMC) and SMC-like adipose-derived stem cells (pADSC) in compressed collagen (CC) hydrogels and to investigate biocompatibility and tissue regeneration of such detrusor-equivalents in a rat detrusorectomy model.

METHODS

Compressed collagen hydrogels seeded with 1 × 10⁶ or 4 × 10⁶ SMC alone or in combination with pADSC in a 1:1 ratio were investigated. Morphology, phenotype, and viability as well as proteomic secretome analysis were assessed in the 1:1 co-cultures and the respective monocultures. The hydrogels were implanted into rat bladders after partial detrusorectomy. Bladders were harvested 8 weeks after transplantation, and assessed for tissue morphology, detrusor regeneration, neo-vascularization and -innervation.

RESULTS

Co-cultured cells exhibited native SMC morphology, high viability and proliferated to form microtissues in vitro. The pro-angiogenic factors angiogenin, vascular endothelial growth factor (VEGF)-A and -D were increased in the secretome of the pADSC samples. After 8 weeks of in vivo, the regenerated bladder wall showed a multilayered structure containing all bladder wall components. The overall performance of the bladder wall regeneration of CC seeded with 4 × 10⁶ cells was significantly better than with 1 × 10⁶ cells and the combination SMC:pADCS performed slightly better than SMC alone.

CONCLUSION

Compressed collagen possesses an adequate regenerative potential to promote regeneration of bladder wall tissue in vivo. Seeded with a combination of pADSC and SMC this may well be the first step towards a functional bladder reconstruction especially in patients suffering of end-stage bladder diseases.

Urinary biomarkers profiles in patients with neurogenic detrusor overactivity according to their neurological condition

OBJECTIVES

The aim of this study was to investigate the disease-specific urinary levels variations of neurotrophins (NGF, BDNF), mediators of inflammation (TGFβ-1, PGE-2) and markers of extracellular matrix alterations (TIMP-2) in patients with multiple sclerosis (MS) spinal cord injury (SCI), or spina bifida (SB), and neurogenic detrusor overactivity (NDO).

METHODS

A prospective single-center study was conducted between March 2015 and March 2017. Patients aged over 18 years old, with neurological disease, with a urodynamic diagnosis of NDO were included. The urinary levels of NGF, BDNF, TIMP-2, PGE 2, and TGF-β1 were measured using dedicated ELISA kits.

RESULTS

Forty-one patients were included: 6 with MS, 20 with SCI, and 15 with spina bifida. The average urinary level of NGF/Cr was significantly higher in MS patients compared to other neurologic populations (8 vs. 0.56 vs. 1.25 pg/mg of creatinine; p = 0.001) as well for the average urinary level of BDNF (88.3 vs. 5 vs. 4.8 pg/mg of creatinine; p < 0.0001). SCI patients had a significantly lower level of TGFβ-1 than SB patients (p = 0.04). The urinary level of PGE2 was significantly correlated with the Body Mass Index (r = 0.61; p = 0.0002).

CONCLUSION

All NDO may not be created equal from the molecular standpoint. Multiple sclerosis patients had higher urinary levels of neurotrophins than in other neurologic populations with NDO. Urinary TGFβ-1, a strong determinant of extracellular matrix, was significantly higher in spina bifida patients compared to SCI patients. These findings underscore the importance of using and interpreting those possible urinary markers in a disease-specific fashion.

Neurological dysfunction of the bladder from myelomeningocele

Myelomeningocele (MMC) affects approximately 2000 infants in the US yearly and causes long-term damage to the genitourinary system. There is a wide spectrum of effects on the bladder and urethral sphincter that do not correlate with the level of the spinal cord defect. The bladder changes can provide a safe storage pressure, often at the expense of continence, or can create a hostile environment leading to increased pressure on the kidneys and eventually to chronic kidney disease. The ultimate goals in management are to maintain a safe system that prevents renal deterioration, while providing social continence and independence in the long term. This review intends to provide an overview of the effects of MMC on the genitourinary system, regardless of intervention, in order to understand the pathophysiology of the disease.

Intradetrusor Injections of Botulinum Toxin A in Adults with Spinal Dysraphism

PURPOSE

The aim of the current study was to determine the outcomes of botulinum toxin A intradetrusor injections in adult patients with spina bifida.

MATERIALS AND METHODS

All patients with spinal dysraphism who underwent intradetrusor injections of botulinum toxin A from 2002 to 2016 at a total of 14 centers were retrospectively included in analysis. The primary end point was the global success of injections, defined subjectively as the combination of urgency, urinary incontinence and detrusor overactivity/low bladder compliance resolution. Univariate and multivariate analysis was performed to seek predictors of global success.

RESULTS

A total of 125 patients were included in study. The global success rate of the first injection was 62.3% with resolution of urinary incontinence in 73.5% of patients. All urodynamic parameters had improved significantly by 6 to 8 weeks compared to baseline, including maximum detrusor pressure (-12 cm H₂O, p <0.001), maximum cystometric capacity (86.6 ml, p <0.001) and compliance (8.9 ml/cm H₂O, p = 0.002). A total of 20 complications (3.6%) were recorded for the 561 intradetrusor botulinum toxin A injections, including 3 muscular weakness complications. The global success rate of the first injection was significantly lower in patients with poor compliance (34.4% vs 86.9%, OR 0.08, p <0.001). On multivariate analysis poor compliance was associated with a lower global success rate (OR 0.13, p <0.001). Female gender (OR 3.53, p = 0.01) and patient age (OR 39.9, p <0.001) were predictors of global success.

CONCLUSIONS

Intradetrusor botulinum toxin A injections were effective in adult patients with spina bifida who had detrusor overactivity. In contrast, effectiveness was much lower in adult patients with spina bifida who had poor bladder compliance. The other predictors of global success were female gender and older age.

Intradetrusor Injections of Botulinum Toxin Type A in Children With Spina Bifida: A Multicenter Study

OBJECTIVE

To assess the effectiveness of intradetrusor injections of botulinum toxin type A (IDBTX-A) in children with spina bifida.

METHODS

All patients aged less than 16 years old who underwent IDBTX-A between 2002 and 2016 at 6 institutions were included in a retrospective study. Our primary endpoint was the success rate of IDBTX-A defined as both clinical improvement (no incontinence episodes between clean intermittent catheterizations [CICs], absence of urgency, and less than 8 CICs per day) and urodynamic improvement (resolution of detrusor overactivity and normal bladder compliance for age) lasting ≥12 weeks. Predictive factors of success were assessed through univariate analysis.

RESULTS

Fifty-three patients with a mean age of 8.5 years were included. All patients were under CIC and 88.7% had received anticholinergics with either poor efficacy or bothersome adverse events. The global success rate of the first injection (clinical and urodynamic) was 30%. Patients with closed spinal dysraphism had a significantly better success rate than patients with myelomeningocele (P = .002). The clinical success rate was 66% and was significantly associated with maximum urethral closure pressure (34 cm H₂O vs 54.4 cm H₂O, P = .02). The urodynamic success rate was 34%. Maximum cystometric capacity (P <.0001) and compliance (P = .01) significantly improved after the first IDBTX-A and maximum detrusor pressure tended to decrease (P = .09) except in the subgroup of patients with poor compliance. After a mean follow-up of 3.7 years, 23 patients (43.4%) required augmentation cystoplasty. Excluding 6 patients who were lost to follow-up, 38.3% of patients were still undergoing botulinum toxin injections at last follow-up.

CONCLUSION

In this series, despite the fact that IDBTX-A enabled clinical improvement in 66% patients, urodynamic outcomes were poor resulting in a low global success rate (30%).

Dynamic reciprocity in cell-scaffold interactions

Tissue engineering in urology has shown considerable promise. However, there is still much to understand, particularly regarding the interactions between scaffolds and their host environment, how these interactions regulate regeneration and how they may be enhanced for optimal tissue repair. In this review, we discuss the concept of dynamic reciprocity as applied to tissue engineering, i.e. how bi-directional signaling between implanted scaffolds and host tissues such as the bladder drives the process of constructive remodeling to ensure successful graft integration and tissue repair. The impact of scaffold content and configuration, the contribution of endogenous and exogenous bioactive factors, the influence of the host immune response and the functional interaction with mechanical stimulation are all considered. In addition, the temporal relationships of host tissue ingrowth, bioactive factor mobilization, scaffold degradation and immune cell infiltration, as well as the reciprocal signaling between discrete cell types and scaffolds are discussed. Improved understanding of these aspects of tissue repair will identify opportunities for optimization of repair that could be exploited to enhance regenerative medicine strategies for urology in future studies.

Bladder tissue regeneration using acellular bi-layer silk scaffolds in a large animal model of augmentation cystoplasty

Acellular scaffolds derived from Bombyx mori silk fibroin were investigated for their ability to support functional tissue regeneration in a porcine model of augmentation cystoplasty. Two bi-layer matrix configurations were fabricated by solvent-casting/salt leaching either alone (Group 1) or in combination with silk film casting (Group 2) to yield porous foams buttressed by heterogeneous surface pore occlusions or homogenous silk films, respectively. Bladder augmentation was performed with each scaffold group (6 × 6 cm(2)) in juvenile Yorkshire swine for 3 m of implantation. Augmented animals exhibited high rates of survival (Group 1: 5/6, 83%; Group 2: 4/4, 100%) and voluntary voiding over the course of the study period. Urodynamic evaluations demonstrated mean increases in bladder capacity over pre-operative levels (Group 1: 277%; Group 2: 153%) which exceeded nonsurgical control gains (144%) encountered due to animal growth.In addition, animals augmented with both matrix configurations displayed increases in bladder compliance over pre-operative levels(Group 1: 357%; Group 2: 338%) similar to growth-related elevations observed in non-surgical controls (354%) [corrected]. Gross tissue evaluations revealed that both matrix configurations supported extensive de novo tissue formation throughout the entire original implantation site which exhibited ultimate tensile strength similar to nonsurgical counterparts. Histological and immunohistochemical analyses showed that both implant groups promoted comparable extents of smooth muscle regeneration and contractile protein (α-smooth muscle actin and SM22α) expression within defect sites similar to controls. Parallel evaluations demonstrated the formation of a transitional, multi-layered urothelium with prominent cytokeratin, uroplakin, and p63 protein expression in both matrix groups. De novo innervation and vascularization processes were evident in all regenerated tissues indicated by synaptophysin-positive neuronal cells and vessels lined with CD31 expressing endothelial cells. Ex vivo organ bath studies demonstrated that regenerated tissues supported by both silk matrices displayed contractile responses to carbachol, α,β-methylene-ATP, KCl, and electrical field stimulation similar to controls. Our data detail the ability of acellular silk scaffolds to support regeneration of innervated, vascularized smooth muscle and urothelial tissues within 3 m with structural, mechanical, and functional properties comparable to native tissue in a porcine model of bladder repair.

Evaluation of silk biomaterials in combination with extracellular matrix coatings for bladder tissue engineering with primary and pluripotent cells

Silk-based biomaterials in combination with extracellular matrix (ECM) coatings were assessed as templates for cell-seeded bladder tissue engineering approaches. Two structurally diverse groups of silk scaffolds were produced by a gel spinning process and consisted of either smooth, compact multi-laminates (Group 1) or rough, porous lamellar-like sheets (Group 2). Scaffolds alone or coated with collagen types I or IV or fibronectin were assessed independently for their ability to support attachment, proliferation, and differentiation of primary cell lines including human bladder smooth muscle cells (SMC) and urothelial cells as well as pluripotent cell populations, such as murine embryonic stem cells (ESC) and induced pluripotent stem (iPS) cells. AlamarBlue evaluations revealed that fibronectin-coated Group 2 scaffolds promoted the highest degree of primary SMC and urothelial cell attachment in comparison to uncoated Group 2 controls and all Group 1 scaffold variants. Real time RT-PCR and immunohistochemical (IHC) analyses demonstrated that both fibronectin-coated silk groups were permissive for SMC contractile differentiation as determined by significant upregulation of α-actin and SM22α mRNA and protein expression levels following TGFβ1 stimulation. Prominent expression of epithelial differentiation markers, cytokeratins, was observed in urothelial cells cultured on both control and fibronectin-coated groups following IHC analysis. Evaluation of silk matrices for ESC and iPS cell attachment by alamarBlue showed that fibronectin-coated Group 2 scaffolds promoted the highest levels in comparison to all other scaffold formulations. In addition, real time RT-PCR and IHC analyses showed that fibronectin-coated Group 2 scaffolds facilitated ESC and iPS cell differentiation toward both urothelial and smooth muscle lineages in response to all trans retinoic acid as assessed by induction of uroplakin and contractile gene and protein expression. These results demonstrate that silk scaffolds support primary and pluripotent cell responses pertinent to bladder tissue engineering and that scaffold morphology and fibronectin coatings influence these processes.

Characterization of the human smooth muscle cell secretome for regenerative medicine

Smooth muscle cells (SMC) play a central role in maintaining the structural and functional integrity of muscle tissue. Little is known about the early in vitro events that guide the assembly of 'bioartificial tissue' (constructs) and recapitulate the key aspects of smooth muscle differentiation and development before surgical implantation. Biomimetic approaches have been proposed that enable the identification of in vitro processes which allow standardized manufacturing, thus improving both product quality and the consistency of patient outcomes. One essential element of this approach is the description of the SMC secretome, that is, the soluble and deposited factors produced within the three-dimensional (3D) extracellular matrix (ECM) microenvironment. In this study, we utilized autologous SMC from multiple tissue types that were expanded ex vivo and generated with a rigorous focus on operational phenotype and genetic stability. The objective of this study was to characterize the spatiotemporal dynamics of the first week of organoid maturation using a well-defined in vitro-like, 3D-engineered scale model of our validated manufacturing process. Functional proteomics was used to identify the topological properties of the networks of interacting proteins that were derived from the SMC secretome, revealing overlapping central nodes related to SMC differentiation and proliferation, actin cytoskeleton regulation, and balanced ECM accumulation. The critical functions defined by the Ingenuity Pathway Analysis included cell signaling, cellular movement and proliferation, and cellular and organismal development. The results confirm the phenotypic and functional similarity of the SMC generated by our platform technology at the molecular level. Furthermore, these data validate the biomimetic approaches that have been established to maintain manufacturing consistency.

Expansion of the human adipose-derived stromal vascular cell fraction yields a population of smooth muscle-like cells with markedly distinct phenotypic and functional properties relative to mesenchymal stem cells

Adipose tissue contains a heterogeneous cell population composed of endothelial cells, adipocytes, smooth muscle cells (SMC), and mesenchymal progenitors and stromal cells that meet the criteria put forth by the International Society for Cellular Therapy as defining mesenchymal stem cells (MSC). In this study, we expanded the stromal vascular fraction (SVF) of human adipose tissue and characterized the resulting adherent primary cell cultures by quantitative reverse transcription-polymerase chain reaction, antigen expression, protein fingerprinting, growth kinetics, in vitro tri-lineage differentiation bioactivity, and functional responses to small molecules modulating SMC-related developmental pathways and compared the results to those obtained with functionally validated MSC cultures. SVF-derived initial cultures (P0) were expanded in a defined medium that was not optimized for MSC growth conditions, neither were recombinant cytokines or growth factors added to the media to direct differentiation. The adherent cell cultures derived from SVF expansion under these conditions had markedly distinct phenotypic and biological properties relative to functionally validated MSC cultures. SVF-derived adherent cell cultures retained characteristics consistent with the SMC subpopulation within adipose tissue--phenotype, gene, and protein expression--that were independent of passage number and source of SVF (n=4 independent donors). SVF-derived cells presented significantly less robust in vitro tri-lineage differentiation bioactivity relative to validated MSC. Expanded SVF cells and MSC had opposite responses to the thromboxane A2 mimetic U46619, demonstrating an unambiguous functional distinction between the two cell types. Taken together, these data support the conclusions that SVF cells expanded under the conditions described in these studies are accurately described as adipose-derived SMC and represent a cellular subpopulation of adipose SVF that is separate and distinct from other classes of adipose-derived cells.

The effect of epigenetic therapy on congenital neurogenic bladders--a pilot study

OBJECTIVES

To demonstrate that human smooth muscle cells derived from neurogenic bladders produce more collagen in vitro than smooth muscle cells derived from normal bladders, and that epigenetic therapy may normalize this increased collagen production.

METHODS

Human smooth muscle cells from normal (n = 3) and neurogenic bladders (n = 3) were cultured in normal culture media and at different concentrations of the histone deacetylase inhibitors trichostatin A, valproic acid, and the DNA methylation inhibitor 5-azacytidine (5-aza). Collagen type I and III gene expression was measured using real-time quantitative reverse transcription-polymerase chain reaction after varying doses of drug exposure. Cell viability was measured using trypan blue.

RESULTS

The smooth muscle cells from neurogenic bladders released significantly more collagen than the normal bladder cells (mean 4.1 vs 1.8 microg/mL in control media) when grown in normal conditions. Treatment with trichostatin A at 50 ng/mL decreased the collagen level in cells from neurogenic bladders to almost normal levels (2.1 microg/mL). In addition, valproic acid treatment decreased collagen types I and III gene expression relative to controls, with maximal effect at 300 mg/mL. These treatments had little effect on cell viability.

CONCLUSIONS

Histone deacetylase inhibitors decreased collagen production of smooth muscle cells from neurogenic bladders in vitro. These agents may be a means of effectively preventing bladder fibrosis in patients with this condition.

The bladder extracellular matrix. Part I: architecture, development and disease

From the earliest studies with epithelial cells implanted into detrusor muscle to later experiments on smooth muscle in defined collagen gels, cell niche and extracellular matrix (ECM) have been clearly shown to orchestrate cellular behavior and fate whether quiescent, migratory, or proliferative. Normal matrix can revert transformed cells to quiescence, and damaged matrix can trigger malignancy or dedifferentiation. ECM influence in disease, development, healing and regeneration has been demonstrated in many other fields of study, but a thorough examination of the roles of ECM in bladder cell activity has not yet been undertaken. Structural ECM proteins, in concert with adhesive proteins, provide crucial structural support to the bladder. Both structural and nonstructural components of the bladder have major effects on smooth muscle function, through effects on matrix rigidity and signaling through ECM receptors. While many ECM components and receptors identified in the bladder have specific known functions in the vascular smooth musculature, their function in the bladder is often less well defined. In cancer and obstructive disease, the ECM has a critical role in pathogenesis. The challenge in these settings will be to find therapies that prevent hyperproliferation and encourage proper differentiation, through an understanding of matrix effects on cell biology and susceptibility to therapeutics.

The molecular pathways behind bladder stretch injury

Stretch injury is a non-reversible process that changes the cellular and extracellular characteristics of the bladder wall, leading to bladder dysfunction. Posterior urethral valve and neurogenic bladder are examples of disorders that may lead to stretch injury. There is a lack of understanding of the molecular processes leading to stretch injury. The current literature is reviewed in this paper, with the aim of giving some insight into the molecular and genetic pathways of bladder stretch injury.