Myostatin Overexpression and Smad Pathway in Detrusor Derived from Pediatric Patients with End-Stage Lower Urinary Tract Dysfunction.

Cell therapies and tissue engineering approaches using smooth muscle cells (SMCs) may provide treatment alternatives for end-stage lower urinary tract dysfunction (ESLUTD). Myostatin, a negative regulator of muscle mass, is a promising target to improve muscle function through tissue engineering. The ultimate goal of our project was to investigate the expression of myostatin and its potential impact in SMCs derived from healthy pediatric bladders and pediatric ESLUTD patients. Human bladder tissue samples were evaluated histologically, and SMCs were isolated and characterized. The proliferation of SMCs was assessed by WST-1 assay. The expression pattern of myostatin, its pathway and the contractile phenotype of the cells were investigated at gene and protein levels by real-time PCR, flow cytometry, immunofluorescence, WES and gel contraction assay. Our results show that myostatin is expressed in human bladder smooth muscle tissue and in isolated SMCs at gene and protein levels. A higher expression of myostatin was detected in ESLUTD-derived compared to control SMCs. Histological assessment of bladder tissue confirmed structural changes and decreased muscle-to-collagen ratios in ESLUTD bladders. A decrease in cell proliferation and in the expression of key contractile genes and proteins, α-SMA, calponin, smoothelin and MyH11, as well as a lower degree of in vitro contractility was observed in ESLUTD-derived compared to control SMCs. A reduction in the myostatin-related proteins Smad 2 and follistatin, and an upregulation in the proteins p-Smad 2 and Smad 7 were observed in ESLUTD SMC samples. This is the first demonstration of myostatin expression in bladder tissue and cells. The increased expression of myostatin and the changes in the Smad pathways were observed in ESLUTD patients. Therefore, myostatin inhibitors could be considered for the enhancement of SMCs for tissue engineering applications and as a therapeutic option for patients with ESLUTD and other smooth muscle disorders.

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.

Spheroids of Bladder Smooth Muscle Cells for Bladder Tissue Engineering.

Cell-based tissue engineering (TE) has been proposed to improve treatment outcomes in end-stage bladder disease, but TE approaches with 2D smooth muscle cell (SMC) culture have so far been unsuccessful. Here, we report the development of primary bladder-derived 3D SMC spheroids that outperform 2D SMC cultures in differentiation, maturation, and extracellular matrix (ECM) production. Bladder SMC spheroids were compared with 2D cultures using live-dead staining, qRT-PCR, immunofluorescence, and immunoblotting to investigate culture conditions, contractile phenotype, and ECM deposition. The SMC spheroids were viable for up to 14 days and differentiated rather than proliferating. Spheroids predominantly expressed the late myogenic differentiation marker MyH11, whereas 2D SMC expressed more of the general SMC differentiation marker α-SMA and less MyH11. Furthermore, the expression of bladder wall-specific ECM proteins in SMC spheroids was markedly higher. This first establishment and analysis of primary bladder SMC spheroids are particularly promising for TE because differentiated SMCs and ECM deposition are a prerequisite to building a functional bladder wall substitute. We were able to confirm that SMC spheroids are promising building blocks for studying detrusor regeneration in detail and may provide improved function and regenerative potential, contributing to taking bladder TE a significant step forward.

A rare case of symptomatic hydrometrocolpos in a 5y old female.

Late presentation of symptomatic hydrometrocolpos is uncommon. We present a 5 years old continent girl with prenatally diagnosed multicystic dysplastic left kidney and late-onset of lower abdominal pain. Investigations revealed a nonfunctioning left kidney with an ectopic ureter draining into the left hemivagina, and a vaginal duplication with an obstructed and urine-filled left hemivagina. Surgical therapy included resection of the vaginal septum and laparoscopic nephroureterectomy. Not only renal agenesis but also dysplasia or multicystic kidney may part of an OHVIRA syndrome. In girls with unilateral renal dysplasia, a duplication of the internal genitalia must always be considered.

Fetal surgery for spina bifida in Zurich: results from 150 cases.

PURPOSE: Over the past 10 years, over 150 fetal spina bifida surgeries were performed at the Zurich Center for Fetal Diagnosis and Therapy. This study looks at surrogates for success and failure of this approach. METHODS: We focused on key outcome parameters including hydrocephalus shunt rate at one year, bladder control at 4, independent ambulation at 3 years, and maternal, fetal, and neonatal complications. RESULTS: From the first 150 patients undergoing fetal surgery for spina bifida, 148 (98.7%) were included in the study. Maternal-fetal surgery was uneventful in 143/148 (97%) cases. Intraoperative problems included resuscitation in 4/148 fetuses (2.7%). 1/148 fetuses (0.7%) died on postoperative day 4. Maternal complications included chorioamniotic membrane separation in 22/148 (15%), lung embolism in 3/148 (2.1%), chorioamnionitis in 2/148 (1.4%), AV-block III and uterine rupture in 1/148 each (0.7%). 1/148 (0.7%) newborn death was recorded. Hindbrain herniation was identified preoperatively in 132/148 (90%) fetuses and resolved completely in 119/132 (90%). At one year, 39/106 (37%) children had required a CSF diversion. At 4 years, 4/34 patients (12%) had normal bladder control. At 3 years, 48/57 (84%) walked independently. CONCLUSION: A majority of patients benefitted from prenatal intervention, in that the shunt rate was lower and the rates of continent and walking patients were higher than reported with postnatal care.

Urological Outcome after Fetal Spina Bifida Repair: Data from the Zurich Cohort.

INTRODUCTION: Neurogenic lower urinary tract dysfunction (NLUTD) represents a severe burden for patients with open spina bifida (OSB). The effect of fetal OSB repair on the urological outcome remains unclear, as controversial data exist. The aim of this study was to further increment existing outcome data and to demonstrate that our earlier published positive preliminary results are not erratic. METHODS: Data from standardized urological follow-up appointments of patients with fetal OSB repair operated at our center were analyzed. Data were obtained from urodynamic studies (UDSs) and radiologic exams performed in the newborn (gestational age 37-39 weeks), at ages of 6, 12, 18, and 24 months, and then at yearly intervals. RESULTS: Of 82 patients (mean age 2.6 years, range 6 months to 7 years), 26 (32%) had a normal bladder function as demonstrated by UDSs. Of the 56 (68%) patients with NLUTD, 29 (51%) patients showed initially a normal UDS, but developed NLUTD in the follow-up, 19 (66%) of them spontaneously and another 10 (34%) in association with growth and development, or surgery of inclusion cysts. Radiologic abnormalities (upper tract dilatation and vesico-uretero-renal reflux) were seen in 15%, mainly patients with NLUTD. CONCLUSION: Our results add an important set of information to the existing body of evidence. The data reconfirm our earlier published favorable preliminary results and support other studies that show a possible benefit of prenatal OSB repair on the urological outcome, but they also demonstrate that the positive effect remains limited.

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.

Predifferentiated Smooth Muscle-Like Adipose-Derived Stem Cells for Bladder Engineering.

Introduction: All organs of human body are a conglomerate of various cell types with multidirectional interplay between the different cells and the surrounding microenvironment, leading to a stable tissue formation, homeostasis, and function. To develop a functional smooth muscle tissue, we need to simulate and create a multicellular microenvironment. The multilineage adipose-derived stem cells (ADSCs), which can be easily harvested in large numbers, may provide an alternative cell source for the replacement of smooth muscle cells (SMCs) in cell-based detrusor bioengineering therapeutic approaches. The aim of this study was to investigate whether predifferentiated smooth muscle-like ADSC (pADSC) can support SMCs to generate stable smooth muscle tissue through remodeling of extracellular matrix (ECM) and factor secretion. Methods: Rat SMC and pADSC were mono- and cocultured in the cell ratios 1:1, 1:2, 1:3, and 1:5 (SMC-pADSC) and grown for up to 2 weeks in vitro. The expression of the SMC-specific markers alpha-smooth muscle actin, calponin, myosin heavy chain 11 (MyH11), and smoothelin was assessed, and cell proliferation and contractility were analyzed. Proteomic analysis of the secretome (cell-cell contact was compared with a noncontact transwell 1:1 coculture) and the cell pellets was performed, with the focus on ECM deposition and remodeling, integrin expression and growth factor secretion. Results: SMC and pADSC were strongly positive for all smooth muscle markers. After 1 and 2 weeks of culture, the 1:1 cell ratio developed a significantly higher number of smooth muscle organoids and improved contractility. These organoids were highly structured, consisting of an SMC core surrounded by a pADSC layer. The deposition of various EMC proteins, such as collagens 1a1, 1a2, 2a1, 3a1, 5a2, 6a2, 12a1, and fibrillin 1, was significantly increased. A decreased matrix metalloproteinase 3 (MMP3), MMP9 and MMP13 secretion, as well as increased tissue inhibitors of metalloproteinase 1 (TIMP1) and TIMP2 secretion were found in the contact coculture compared with the monoculture controls. Conclusion: SMC-pADSC 1:1 cocultures exhibit an improved cell proliferation, contractility, and organoid formation compared with all other ratios and monoculture, while retaining a stable phenotype that is comparable with the SMC monoculture. These effects are mediated by increased ECM deposition and tight ECM remodeling by the secreted MMP and TIMP. Impact statement Harvesting smooth muscle cells (SMCs) from diseased bladders represents a significant limitation for clinical translation of bladder Tissue Engineering. Our results suggest that autologous predifferentiated smooth muscle-like adipose-derived stem cell can substitute SMCs, and may be used in combination with SMCs to generate contractile detrusor muscle tissue for patients suffering from end-stage bladder diseases. We demonstrate a beneficial effect when using these cells in a 1:1 ratio with improved deposition of extracellular matrix (ECM) molecules and superior remodeling of the ECM by matrix metalloproteinases and decreased tissue inhibitors of metalloproteinase activity.

Tissue Engineering in Pediatric Bladder Reconstruction-The Road to Success.

Several congenital disorders can cause end stage bladder disease and possibly renal damage in children. The current gold standard therapy is enterocystoplasty, a bladder augmentation using an intestinal segment. However, the use of bowel tissue is associated with numerous complications such as metabolic disturbance, stone formation, urine leakage, chronic infections, and malignancy. Urinary diversions using engineered bladder tissue would obviate the need for bowel for bladder reconstruction. Despite impressive progress in the field of bladder tissue engineering over the past decades, the successful transfer of the approach into clinical routine still represents a major challenge. In this review, we discuss major achievements and challenges in bladder tissue regeneration with a focus on different strategies to overcome the obstacles and to meet the need for living functional tissue replacements with a good growth potential and a long life span matching the pediatric population.

Inclusion Cysts after Fetal Spina Bifida Repair: A Third Hit?

INTRODUCTION: Fetal spina bifida repair (fSBR) has proven effective in the reversibility of hindbrain herniation, lower rate of shunt-dependent hydrocephalus, and independent ambulation. Besides distinct advantages, there are also concerns related to fSBR. One of these is the postnatal occurrence of inclusion cysts (IC). METHODS: In a prospective study, 48 children who underwent fSBR were followed up. Postnatal assessment included clinical examination, cystometry, and spinal MRI. Indication for IC resection was the evidence of a spinal mass on MRI in the presence of deteriorating motor or bladder function, pain, or considerable growth of the IC. RESULTS: Fourteen children (30%) developed IC, all within the first 2 years of life. Six children underwent IC resection; 4 children due to deteriorating function, 2 children due to doubling of the mass on MRI within 1 year. Following IC resection, 4/6 children (67%) demonstrated altered motor function and 6 children (100%) were diagnosed with neurogenic bladder dysfunction. CONCLUSIONS: Systematic follow-up of patients with a history of fSBR revealed a high incidence of IC. Whether these are of dysembryogenic or iatrogenic origin, remains unclear. Since both IC per se and IC resection may lead to loss of neurologic function, IC can be considered a "third hit".

Increased autophagy contributes to impaired smooth muscle function in neurogenic lower urinary tract dysfunction.

AIMS: To explore whether autophagy plays a role in the remodeling of bladder smooth muscle cells (SMCs) in children with neurogenic lower urinary tract dysfunction (NLUTD), we investigated the effect of autophagy in NLUTD in the paediatric population. METHODS: Bladder biopsies were taken from children with NLUTD and healthy donors as controls. Samples were labeled with the SMC markers calponin, smoothelin, and the autophagy proteins LC3, ATG5, and Beclin1. The contractile ability of bladder derived SMCs was investigated. RESULTS: ATG5 gene and protein was upregulated in NLUTD muscle tissue compared to normal bladder. NLUTD muscle exhibited a punctated immunostaining pattern for LC3 in a subset of the SMCs, confirming the accumulation of autophagosomes. Pronounced elevation of ATG5 in the SMC in NLUTD tissue was associated with a downregulation of the key contractile proteins smoothelin and calponin. Pharmacological blocking of autophagy completely stopped the cells growth in normal bladder SMCs. Inhibition of autophagy in the NLUTD SMCs, with already elevated levels of ATG5, resulted in a reduction of ATG5 protein expression to the basal level found in normal controls. CONCLUSIONS: Our study suggests that autophagy is an important factor affecting the remodeling of SMCs and the alteration of functionality in bladder smooth muscle tissue in the NLUTD. Since autophagy can be influenced by oral medication, this finding might lead to novel strategies preventing the deterioration of NLUTD muscle.

Bladder regeneration through stem cell therapy.

INTRODUCTION: Impaired bladder function in children and adults often causes lifelong morbidity, as functional therapeutic approaches in this field are nonexistent. If reconstructive procedures are required, intestinal tissue is used as a gold standard for bladder repair. As this procedure is associated with significant long-term complications there is a strong clinical need for alternative sources of stable and reliable bladder tissue, of which stem cells are considered most promising. AREAS COVERED: This review focusses on the recent development in stem cell use for bladder bioengineering. Further, we discuss the importance of the microenvironment in stem cell differentiation, function and tissue regeneration and its effect on the development of functional bladder tissue. EXPERT OPINION: Functional bladder bioengineering requires a complex approach that involves the development of a multi-layered scaffold, with each layer offering a specific microenvironment for the generation and support of the respective cell type used in its redevelopment. The formation of cellular cross-talk within and between the layers is the key in this process. While autologous stem cells may provide a viable source of tissue for bladder reconstruction, their in situ activation combined with repair of the diseased microenvironment may offer better, more lasting solutions for functional bladder regeneration.

The Effect of Wound Dressings on a Bio-Engineered Human Dermo-Epidermal Skin Substitute in a Rat Model.

Autologous bio-engineered dermo-epidermal skin substitutes are a promising treatment for large skin defects such as burns. For their successful clinical application, the graft dressing must protect and support the keratinocyte layer and, in many cases, possess antimicrobial properties. However, silver in many antimicrobial dressings may inhibit keratinocyte growth and differentiation. The purpose of our study was to evaluate the effect of various wound dressings on the healing of a human hydrogel-based dermo-epidermal skin substitute in preparation for the first-in-human clinical trials. Human dermo-epidermal skin substitutes approved for clinical trials were produced under good manufacturing practice conditions, transplanted onto immuno-incompetent rats, and dressed with either Vaseline Gauze™ (Kendall Medtronic, Minneapolis, USA), Suprathel (PolyMedics Innovations GmbH, Denkendorf, Germany), Urgotul SSD (Urgo Medical, Shepshed, United Kingdom), Mepilex AG (Mölnlycke Health Care, Gothenburg, Sweden), or Acticoat™ (Smith&Nephew, Baar, Switzerland). Grafts were assessed clinically for take, epithelialization, and infection at 10 and 21 days post-transplantation, and histologically at 21 days. There were three subjects each in the Vaseline Gauze™ and Suprathel groups, and four subjects each in the Urgotul SSD, Mepilex AG, and Acticoat™ groups. For all samples, the take rate was 100% and the expected keratinocyte number, epithelialization and epidermal stratification were observed. All of the dressings in the current study were well tolerated by our human dermo-epidermal skin substitute. The tolerance of the silver-based dressings is particularly relevant given the high risk of bacterial contamination with large skin defects, and provides pivotal information as we embark on clinical trials for this novel skin substitute.

Prenatal myelomeningocele repair: Do bladders better?

AIMS: Prenatal myelomeningocele (MMC) repair has been proven to significantly reduce the need for hydrocephalus shunting and improve lower-extremity motor outcomes. The aim of this study was to evaluate the effect of prenatal MMC repair on the urological outcome. METHODS: All patients who underwent fetal MMC repair at our institution are followed prospectively. Assessments include medical history, renal and bladder ultrasound, voiding cystourethrogram and urodynamic study, need for clean intermittent catheterization (CIC) and anticholinergics, and the occurrence of urinary tract infections (UTI). RESULTS: Of the 30 patients who underwent prenatal MMC closure from December 2010 to December 2015, eight patients with a postnatal follow-up of at least 2 years were included in this study and compared with eight patients after postnatal MMC repair. The level of the bony spinal defect was similar in both groups. Urological evaluation at 2 years revealed normal bladder function in 50% after prenatal repair. Neurogenic bladder dysfunction requiring CIC and anticholinergic therapy was seen in 50% in the prenatal and in 100% in the postnatal group. Significant bladder wall thickening was found in 37.5% and 87.5%, respectively. Febrile UTIs occurred in 37.5% in the prenatal and 62.5% in the postnatal group during the observation period. CONCLUSIONS: Our data suggest a positive effect of prenatal MMC closure on lower urinary tract function. The long-term significance of these results remains unclear. Therefore, continued close monitoring of renal and bladder function are mandatory.

Polyesterurethane and acellular matrix based hybrid biomaterial for bladder engineering.

Poly(lactic-co-glycolic acid) (PLGA) based biomaterials for soft tissue engineering have inherent disadvantages, such as a relative rigidity and a limited variability in the mechanical properties and degradation rates. In this study, a novel electrospun biomaterial based on degradable polyesterurethane (PEU) (DegraPol® ) was investigated for potential use for bladder engineering in vitro and in vivo. Hybrid microfibrous PEU and PLGA scaffolds were produced by direct electrospinning of the polymer onto a bladder acellular matrix. The scaffold morphology of the scaffold was analyzed, and the biological performance was tested in vitro and in vivo using a rat cystoplasty model. Anatomical and functional outcomes after implantation were analyzed macroscopically, histologically and by cystometry, respectively. Scanning electron microscopy analysis showed that PEU samples had a lower porosity (p < 0.001) and were slightly thinner (p = 0.009) than the PGLA samples. Proliferation and survival of the seeded smooth muscle cells in vitro were comparable on PEU and PLGA scaffolds. After 8 weeks in vivo, the PEU scaffolds exhibited no shrinkage. However, cystometry of the reconstructed bladders exhibited a slightly greater functional bladder capacity in the PLGA group. Morphometric analyses revealed significantly better tissue healing (p < 0.05) and, in particular, better smooth muscle regeneration, as well as a lower rate of inflammatory responses at 8 weeks in the PEU group. Collectively, the results indicated that PEU-hybrid scaffolds promote bladder tissue formation with excellent tissue integration and a low inflammatory reaction in vivo. PEU is a promising biomaterial, particularly with regard to functional tissue engineering of the bladder and other hollow organs. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 658-667, 2017.

Stem Cells in Functional Bladder Engineering.

Conditions impairing bladder function in children and adults, such as myelomeningocele, posterior urethral valves, bladder exstrophy or spinal cord injury, often need urinary diversion or augmentation cystoplasty as when untreated they may cause severe bladder dysfunction and kidney failure. Currently, the gold standard therapy of end-stage bladder disease refractory to conservative management is enterocystoplasty, a surgical enlargement of the bladder with intestinal tissue. Despite providing functional improvement, enterocystoplasty is associated with significant long-term complications, such as recurrent urinary tract infections, metabolic abnormalities, stone formation, and malignancies. Therefore, there is a strong clinical need for alternative therapies for these reconstructive procedures, of which stem cell-based tissue engineering (TE) is considered to be the most promising future strategy. This review is focused on the recent progress in bladder stem cell research and therapy and the challenges that remain for the development of a functional bladder wall.

Forearm fractures in children: split opinions about splitting the cast.

BACKGROUND: Fractures of the forearm are the most common fractures in children. Various methods of cast immobilization have been recommended. Currently, there is still controversy regarding the optimal method of treatment, especially regarding the need for cast splitting. METHODS: We conducted a single-center randomized and controlled trial between June 2008 and September 2009. Children younger than 16 years presenting to the emergency department with a closed fracture of the forearm needing reduction were eligible for random assignment to immobilization in a closed or split circumferential semirigid cast. The primary outcome was the incidence of cast-related soft-tissue problems such as compartment syndrome, neurovascular compromise, saw burns, or skin breakdown. The secondary outcome was fracture stability. RESULTS: During this period, 100 patients were randomly assigned to one of the two procedures and analyzed. Follow-up was completed in 99 patients. No compartment syndrome was observed in either group. Moderate skin breakdown (< 2 cm(2)) occurred in two patients, one in the closed cast and one in the split cast group. Secondary splitting was necessary in one patient because of a reversible lymphedema. Significant secondary displacement of the fracture was slightly more common in the split group (5 of 50 patients [10%] vs. 4 of 49 patients [8%] in the closed cast group) without reaching statistical significance. CONCLUSIONS: No significant difference in the incidence of cast-related problems was observed between the groups. Fracture stability was comparable in both groups. We suggest that closed circumferential semirigid casts are a safe and effective immobilization technique for fractures of the forearm in children and splitting can be omitted.

Increased porosity of electrospun hybrid scaffolds improved bladder tissue regeneration.

The object of this study was to investigate the role of scaffold porosity on tissue ingrowth using hybrid scaffolds consisting of bladder acellular matrix and electrospun poly (lactide-co-glycolide) (PLGA) microfibers that mimic the morphological characteristics of the bladder wall in vitro and in vivo. We compared single-spun (SS) PLGA scaffolds with more porous cospun (CS) scaffolds (PLGA and polyethylene glycol). Scaffolds were characterized by scanning electron microscopy. Bladder smooth muscle cells (SMCs) were seeded, and proliferation and histological assays were performed. Sixteen rats were subjected to augmentation cystoplasty with seeded SS or CS scaffolds, morphological, and histological studies were performed 2 and 4 weeks after implantation. The porosities of SS and CS scaffolds were 73.1 ± 2.9% and 80.9 ± 1.5%, respectively. The in vitro evaluation revealed significantly deeper cell migration into CS scaffolds. The in vivo evaluation showed significant shrinkage of SS scaffolds (p = 0.019). The histological analysis revealed a bladder wall-like structure with urothelial lining and SMC infiltration in both groups. The microvessel density was significantly increased in the CS scaffolds (p < 0.001). Increasing the porosity of electrospun hybrid scaffolds is an effective strategy to enhance cell proliferation and distribution in vitro and tissue ingrowth in vivo.

Engineering functional bladder tissues.

PURPOSE: End stage bladder disease can seriously affect patient quality of life and often requires surgical reconstruction with bowel tissue, which is associated with numerous complications. Bioengineering of functional bladder tissue using tissue-engineering techniques could provide new functional tissues for reconstruction. In this review, we discuss the current state of this field and address different approaches to enable physiologic voiding in engineered bladder tissues in the near future. MATERIALS AND METHODS: In a collaborative effort, we gathered researchers from four institutions to discuss the current state of functional bladder engineering. A MEDLINE® and PubMed® search was conducted for articles related to tissue engineering of the bladder, with special focus on the cells and biomaterials employed as well as the microenvironment, vascularisation and innervation strategies used. RESULTS: Over the last decade, advances in tissue engineering technology have laid the groundwork for the development of a biological substitute for bladder tissue that can support storage of urine and restore physiologic voiding. Although many researchers have been able to demonstrate the formation of engineered tissue with a structure similar to that of native bladder tissue, restoration of physiologic voiding using these constructs has never been demonstrated. The main issues hindering the development of larger contractile tissues that allow physiologic voiding include the development of correct muscle alignment, proper innervation and vascularization. CONCLUSION: Tissue engineering of a construct that will support the contractile properties that allow physiologic voiding is a complex process. The combination of smart scaffolds with controlled topography, the ability to deliver multiple trophic factors and an optimal cell source will allow for the engineering of functional bladder tissues in the near future.