Bladder Regeneration Research Articles

Urine-derived stem cells for potential use in bladder repair.

Engineered bladder tissues, created with autologous bladder cells seeded on biodegradable scaffolds, are being developed for use in patients who need cystoplasty. However, in individuals with organ damage from congenital disorders, infection, irradiation, or cancer, abnormal cells obtained by biopsy from the compromised tissue could potentially contaminate the engineered tissue. Thus, an alternative cell source for construction of the neo-organ would be useful. Although other types of stem cells have been investigated, autologous mesenchymal stem cells (MSCs) are most suitable to use in bladder regeneration. These cells are often used as a cell source for bladder repair in three ways - secreting paracrine factors, recruiting resident cells, and trans-differentiation, inducing MSCs to differentiate into bladder smooth muscle cells and urothelial cells. Adult stem cell populations have been demonstrated in bone marrow, fat, muscle, hair follicles, and amniotic fluid. These cells remain an area of intense study, as their potential for therapy may be applicable to bladder disorders. Recently, we have found stem cells in the urine and the cells are highly expandable, and have self-renewal capacity and paracrine properties. As a novel cell source, urine-derived stem cells (USCs) provide advantages for cell therapy and tissue engineering applications in bladder tissue repair because they originate from the urinary tract system. Importantly, USCs can be obtained via a noninvasive, simple, and low-cost approach and induced with high efficiency to differentiate into bladder cells.

Generation of bladder urothelium from human pluripotent stem cells under chemically defined serum- and feeder-free system.

Human stem cells are promising sources for bladder regeneration. Among several possible sources, pluripotent stem cells are the most fascinating because they can differentiate into any cell type, and proliferate limitlessly in vitro. Here, we developed a protocol for differentiation of human pluripotent stem cells (hPSCs) into bladder urothelial cells (BUCs) under a chemically defined culture system. We first differentiated hPSCs into definitive endoderm (DE), and further specified DE cells into BUCs by treating retinoic acid under a keratinocyte-specific serum free medium. hPSC-derived DE cells showed significantly expressed DE-specific genes, but did not express mesodermal or ectodermal genes. After DE cells were specified into BUCs, they notably expressed urothelium-specific genes such as UPIb, UPII, UPIIIa, P63 and CK7. Immunocytochemistry showed that BUCs expressed UPII, CK8/18 and P63 as well as tight junction molecules, E-CADHERIN and ZO-1. Additionally, hPSCs-derived BUCs exhibited low permeability in a FITC-dextran permeability assay, indicating BUCs possessed the functional units of barrier on their surfaces. However, BUCs did not express the marker genes of other endodermal lineage cells (intestine and liver) as well as mesodermal or ectodermal lineage cells. In summary, we sequentially differentiated hPSCs into DE and BUCs in a serum- and feeder-free condition. Our differentiation protocol will be useful for producing cells for bladder regeneration and studying normal and pathological development of the human bladder urothelium in vitro.

Constructs of electrospun PLGA, compressed collagen and minced urothelium for minimally manipulated autologous bladder tissue expansion

Bladder regeneration based on minced bladder mucosa in vivo expansion is an alternative to in vitro culturing of urothelial cells. Here, we present the design of a hybrid, electrospun poly(lactic-co-glycolide) (PLGA) – plastically compressed (PC) collagen scaffold that could allow in vivo bladder mucosa expansion. Optimisation of electrospinning was performed in order to obtain increased pore sizes and porosity to consolidate the construct and to support neovascularisation and tissue ingrowth. Tensile tests showed an increase in average tensile strength from 0.6 MPa for PC collagen to 3.57 MPa for the hybrid construct. The optimised PLGA support scaffold was placed between two collagen gels, and the minced tissue was distributed either on top or both on top and inside the construct prior to PC; this was then cultured for up to four weeks. Morphology, histology and SEM demonstrated that the construct maintained its integrity throughout cell culture. Cells from minced tissue migrated, expanded and re-organised to a confluent cell layer on the top of the construct after two weeks and formed a multilayered urothelium after four weeks. Cell morphology and phenotype was typical for urothelial mucosa during tissue culture.

MP17-03 HYALURONAN AND ITS HYALURONAN RECEPTORS IN RAT BLADDER REGENERATION AND THEIR ROLE IN ANGIOGENESIS

INTRODUCTION AND OBJECTIVES: Hyaluronic acid (HA), a non-sulfated glycosaminoglycan and an essential component of the extracellular matrix (ECM), plays critical roles in phases of wound healing and tissue regeneration. This study was designed to characterize temporal and anatomical HA deposition and its major receptors (CD44, LYVE-1, RHAMM, and HARE) expression in a rat bladder regeneration model and to understand the effectiveness of HA in promoting angiogenesis. METHODS: Fifteen Sprague-Dawley rats were subjected to partial cystectomy with interposition of distal sections of porcine small intestinal submucosa (SIS). SIS-augmented bladders were harvested on post-operative days 2, 7, 14, 28, and 56 for histological studies. Effectiveness of HA in stimulating endothelial cell proliferation, tube formation, and angiogenic activity were determined in vitro cell and ex ovo chick chorioallantoic membrane (CAM) models. RESULTS: Bladder regeneration proceeded without complications; and all regenerated bladders had complete urothelial lining and smooth muscle bundle formation by day 56 post-augmentation. As determined by immunohistochemistry, strong positive HA staining was observed on days 28 and 56 post-operation in the ECM of the stroma. CD44 immunoreactivity was detected on days 28 and 56 in the cytoplasm of urothelial cells and LYVE-1 immunoreactivity was detected exclusively in lymphatic vessels at days 28 and 56. RHAMM mRNA increased within 2 days post-operation, whereas HARE mRNA level did not change during the course of bladder regeneration. Exogenous HA significantly stimulated growth and tube formation of cultured endothelial cells, and enhanced angiogenesis in CAM assay. CONCLUSIONS: During bladder regeneration HA is synthesized throughout the course of regeneration processes. HA deposition coincides with urothelial differentiation. Temporal regulation and spatial distribution of two major HARs (CD44 and LYVE-1) follow the same temporal pattern as HA deposition. Therapeutic modalities through local delivery of exogenous HA can be viable to significantly improve angiogenesis and enhance the outcome and completeness of bladder regeneration.

MP17-04 NOVEL INSIGHTS INTO HUMAN DETRUSOR SMOOTH MUSCLE MUSCARINIC RECEPTOR PHYSIOLOGY: A ROLE FOR THE LARGE CONDUCTANCE VOLTAGE- AND CALCIUM-ACTIVATED POTASSIUM CHANNELS

INTRODUCTION AND OBJECTIVES: Hyaluronic acid (HA), a non-sulfated glycosaminoglycan and an essential component of the extracellular matrix (ECM), plays critical roles in phases of wound healing and tissue regeneration. This study was designed to characterize temporal and anatomical HA deposition and its major receptors (CD44, LYVE-1, RHAMM, and HARE) expression in a rat bladder regeneration model and to understand the effectiveness of HA in promoting angiogenesis. METHODS: Fifteen Sprague-Dawley rats were subjected to partial cystectomy with interposition of distal sections of porcine small intestinal submucosa (SIS). SIS-augmented bladders were harvested on post-operative days 2, 7, 14, 28, and 56 for histological studies. Effectiveness of HA in stimulating endothelial cell proliferation, tube formation, and angiogenic activity were determined in vitro cell and ex ovo chick chorioallantoic membrane (CAM) models. RESULTS: Bladder regeneration proceeded without complications; and all regenerated bladders had complete urothelial lining and smooth muscle bundle formation by day 56 post-augmentation. As determined by immunohistochemistry, strong positive HA staining was observed on days 28 and 56 post-operation in the ECM of the stroma. CD44 immunoreactivity was detected on days 28 and 56 in the cytoplasm of urothelial cells and LYVE-1 immunoreactivity was detected exclusively in lymphatic vessels at days 28 and 56. RHAMM mRNA increased within 2 days post-operation, whereas HARE mRNA level did not change during the course of bladder regeneration. Exogenous HA significantly stimulated growth and tube formation of cultured endothelial cells, and enhanced angiogenesis in CAM assay. CONCLUSIONS: During bladder regeneration HA is synthesized throughout the course of regeneration processes. HA deposition coincides with urothelial differentiation. Temporal regulation and spatial distribution of two major HARs (CD44 and LYVE-1) follow the same temporal pattern as HA deposition. Therapeutic modalities through local delivery of exogenous HA can be viable to significantly improve angiogenesis and enhance the outcome and completeness of bladder regeneration.

MP17-20 CHARACTERIZATION OF FUNCTIONAL BLADDER REGENERATION IN MICE

You have accessJournal of UrologyBladder & Urethra: Anatomy, Physiology & Pharmacology1 Apr 2014MP17-20 CHARACTERIZATION OF FUNCTIONAL BLADDER REGENERATION IN MICE Mona Zarifpour, Jason Sandberg, Mehran Abolbashari, Manasi Vadhavkar, Sneha Kelkar, Aaron Mohs, Frank Marini, Karl−Erik Andersson, and George Christ Mona ZarifpourMona Zarifpour More articles by this author , Jason SandbergJason Sandberg More articles by this author , Mehran AbolbashariMehran Abolbashari More articles by this author , Manasi VadhavkarManasi Vadhavkar More articles by this author , Sneha KelkarSneha Kelkar More articles by this author , Aaron MohsAaron Mohs More articles by this author , Frank MariniFrank Marini More articles by this author , Karl−Erik AnderssonKarl−Erik Andersson More articles by this author , and George ChristGeorge Christ More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.553AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Previous studies have established that subtotal cystectomy (removal of 60-70% of the bladder) provides a valid and unique model of mammalian organ regeneration (1,2). The goal of this study was to characterize this phenomenon in mice, a species that can be genetically engineered to investigate a diverse array of molecular alterations of functional bladder regeneration, including specific cell−based fluorescence imaging technologies. METHODS Female C57 black mice underwent STC, and at 4 and 12 weeks post−STC, bladder regeneration was assessed via cystometry and ex vivo pharmacologic organ bath studies. Histology was also performed to measure bladder wall thickness and the composition/architecture of the bladder wall. RESULTS We observed a time−dependent increase in bladder capacity following STC, such that 12 weeks post−STC, the sizes of regenerated bladders and micturition volumes were indistinguishable from those of age−matched controls (Fig. 1A, C). Bladders emptied completely at all time points studied (i.e., no increases in residual volume), consistent with functional bladder regeneration. There were no significant differences in bladder wall thickness (Fig. 1B) from controls, or in the percentage of smooth muscle in the detrusor layer (not shown). Contraction to pharmacological activation and electrical field stimulation were present in isolated tissue strips from regenerating bladders but were lower than controls at all time points. Initial cell and tissue transplantation studies using fluorescently labeled mice (i.e., transfer of green fluorescence protein bone marrow into red fluorescent protein animals) revealed a participation and contribution of bone marrow derived populations toward functional bladder regeneration. CONCLUSIONS This study extends our investigation of mammalian bladder regeneration from rats to mice. Establishing a validated model for the study of de novo organ regeneration in mice will allow for further characterization of this phenomenon through detailed investigation of its molecular and cellular basis. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e143 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Mona Zarifpour More articles by this author Jason Sandberg More articles by this author Mehran Abolbashari More articles by this author Manasi Vadhavkar More articles by this author Sneha Kelkar More articles by this author Aaron Mohs More articles by this author Frank Marini More articles by this author Karl−Erik Andersson More articles by this author George Christ More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...

Conditioned medium derived from mesenchymal stem cells culture as a intravesical therapy for cystitis interstitials

The treatment of Interstinal Cystitisis (IC) is still challenge for urologist. Available therapies do not result in long-term control of symptoms and do not provide pain relive to patients. Unique abilities of mesenchymal stem cells (MSC) could be used to develop new treatment approaches for Interstitial Cystitis. Conditioned Medium (CM) derived from MSC culture is rich in plenty of growth factors, cytokines and trophic agents which were widely reported to enhance regeneration of urinary bladder in different conditions. This ready mixture of growth factors could be used to develop intravesical therapy for patients with IC. MSC-CM has anti-apoptotic, anti-inflammatory, supportive, angiogenic, immunosuppressive and immunomodulative properties and seems to be ideal substance to prevent IC recurrence and to create favorable environment for regeneration of damaged bladder wall.

Human urinary bladder regeneration through tissue engineering – An analysis of 131 clinical cases

Replacement of urinary bladder tissue with functional equivalents remains one of the most challenging problems of reconstructive urology over the last several decades. The gold standard treatment for urinary diversion after radical cystectomy is the ileal conduit or neobladder; however, this technique is associated with numerous complications including electrolyte imbalances, mucus production, and the potential for malignant transformation. Tissue engineering techniques provide the impetus to construct functional bladder substitutes de novo. Within this review, we have thoroughly perused the literature utilizing PubMed in order to identify clinical studies involving bladder reconstruction utilizing tissue engineering methodologies. The idea of urinary bladder regeneration through tissue engineering dates back to the 1950s. Many natural and synthetic biomaterials such as plastic mold, gelatin sponge, Japanese paper, preserved dog bladder, lyophilized human dura, bovine pericardium, small intestinal submucosa, bladder acellular matrix, or composite of collagen and polyglycolic acid were used for urinary bladder regeneration with a wide range of outcomes. Recent progress in the tissue engineering field suggest that in vitro engineered bladder wall substitutes may have expanded clinical applicability in near future but preclinical investigations on large animal models with defective bladders are necessary to optimize the methods of bladder reconstruction by tissue engineering in humans.

Treatment of bladder dysfunction using stem cell or tissue engineering technique.

Tissue engineering and stem cell transplantation are two important options that may help overcome limitations in the current treatment strategy for bladder dysfunction. Stem cell therapy holds great promise for treating pathophysiology, as well as for urological tissue engineering and regeneration. To date, stem cell therapy in urology has mainly focused on oncology and erectile dysfunction. The therapeutic potency of stem cells (SCs) was originally thought to derive from their ability to differentiate into various cell types including smooth muscle. The main mechanisms of SCs in reconstituting or restoring bladder function are migration, differentiation, and paracrine effects. Nowadays, paracrine effects of stem cells are thought to be more prominent because of their stimulating effects on stem cells and adjacent cells. Studies of stem cell therapy for bladder dysfunction have been limited to experimental models and have been less focused on tissue engineering for bladder regeneration. Bladder outlet obstruction is a representative model. Adipose-derived stem cells, bone marrow stem cells (BMSCs), and skeletal muscle-derived stem cells or muscle precursor cells are used for transplantation to treat bladder dysfunction. The aim of this study is to review stem cell therapy and updated tissue regeneration as treatments for bladder dysfunction and to provide the current status of stem cell therapy and tissue engineering for bladder dysfunction including its mechanisms and limitations.

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.

In vitro comparative evaluation of recombinant growth factors for tissue engineering of bladder in patients with neurogenic bladder

BackgroundTo compare the effects of various recombinant growth factors on bladder regeneration and angiogenesis for tissue engineering of bladder in patients with neurogenic bladder through in vitro cellular biological methods. Materials and methodsHuman bladder smooth muscle cells (HBSMCs) and human bladder urothelial cells (HBUCs) were cultured from patients with neurogenic bladder and used for comparative evaluations of various growth factors. Human umbilical vein endothelial cells (HUVECs) were also used. Eight potential growth factors, platelet-derived growth factor BB (PDGF-BB), platelet-derived growth factor CC (PDGF-CC), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), insulin-like growth factor 1 (IGF-1), hepatocyte growth factor (HGF), and transforming growth factor beta 1 (TGF-β1), were selected and their effects on the proliferation, migration, and wound healing of HBSMCs, HBUCs, and HUVECs were compared. ResultsPDGF-BB, PDGF-CC, bFGF, VEGF, IGF-1, or HGF enhanced the proliferation, migration, and wound healing of HBSMCs, whereas TGF-β1 inhibited their proliferation. Proliferation, migration, and wound healing of HBUCs and HUVECs were enhanced by bFGF, VEGF, EGF, IGF-1, or HGF, whereas inhibited by TGF-β1. PDGF-BB failed to enhance cell activity of HUVECs, whereas PDGF-CC could enhance their migration and wound healing. PDGF-BB, EGF, and VEGF were the most potent factors for stimulating the activities of HBSMCs, HBUCs, and HUVECs, respectively. ConclusionsOur findings suggest the potential use of a combination of PDGF-BB, EGF, and VEGF for bladder regeneration and angiogenesis. The synergetic effects of the three growth factors on cell activities in a three-dimensional scaffold and an animal model with neurogenic bladder need to be further evaluated.

Bladder cancer cell in co-culture induces human stem cell differentiation to urothelial cells through paracrine FGF10 signaling

Fibroblast growth factor 10 (FGF10) is required for embryonic epidermal morphogenesis including brain development, lung morphogenesis, and initiation of limb bud formation. In this study, we investigated the role of FGF10 as a lead induction factor for stem cell differentiation toward urothelial cell. To this end, human multipotent stem cell in vitro system was employed. Human amniotic fluid stem cells were co-cultured with immortalized bladder cancer lines to induce directed differentiation into urothelial cells. Urothelial markers, uroplakin II, III, and cytokeratin 8, were monitored by RT-PCR, immunocytochemistry, and Western blot analysis. Co-cultured stem cells began to express uroplakin II, III, and cytokeratin 8. Targeted FGF10 gene knockdown from bladder cancer cells abolished the directed differentiation. In addition, when FGF10 downstream signaling was blocked with the Mek inhibitor, the co-culture system lost the capacity to induce urothelial differentiation. Exogenous addition of recombinant FGF10 protein promoted stem cell differentiation into urothelium cell lineage. Together, this report suggests that paracrine FGF10 signaling stimulates the differentiation of human stem cell into urothelial cells. Current study provides insight into the potential role of FGF10 as a lead growth factor for bladder regeneration and its therapeutic application for bladder transplantation.

Tissue engineering – experimental method of urinary bladder regeneration

The most common cause of bladder reconstruction is radical cystectomy for invasive bladder cancer. Currently, bowel segments remains, the most widely used in reconstruction of urinary tract. Using of bowel as a "material" for bladder reconstruction is associated with numerous complications. Tissue engineering methods provide opportunities to construct bladder tissue in vitro from autologous cells obtained from non urinary tract system. So far, the most useful cell and matrix type for bladder reconstruction have not been defined. In this work actual knowledge about tissue engineering in bladder regeneration was presented.

Understanding Roles of Porcine Small Intestinal Submucosa in Urinary Bladder Regeneration: Identification of Variable Regenerative Characteristics of Small Intestinal Submucosa

Neuropathic bladders are the result from damages to the central or peripheral nervous system, and ultimately may require surgical reconstruction to increase bladder volumes and to reduce the risk of damages to the kidneys. Surgical reconstruction through bladder augmentation has traditionally been practiced using a segment of the ileum, colon, or stomach from the patient through enterocystoplasty. However, the use of gastrointestinal segments can lead to serious adverse consequences. Porcine small intestinal submucosa (SIS), a xenogeneic, acellular, biocompatable, biodegradable, and collagen-based bioscaffold is best known to encourage bladder regeneration without ex vivo cell seeding before implantation in various experimental and preclinical animal models. Although it has been demonstrated that SIS supports bladder cell growth in vitro, and SIS-regenerated bladders are histologically and functionally indistinguishable from normal functional tissues, clinical utilization of SIS for bladder augmentation has been hampered by inconsistent preclinical results. Several variables in SIS, such as the age of pigs, the region of the small intestine, and method of sterilization, can have different physical properties, biochemical characteristics, inflammatory cell infiltration, and regenerative capacity due to cellular responses in vitro and in vivo. These parameters are particularly important for bladder regeneration due to its specific biological function in urine storage. Clinical application of SIS for surgical bladder reconstruction may require graft materials to be prepared from a specific region of the small intestine, or to be further formulated or processed to provide uniform physical and biochemical properties for consistent, complete, and functional bladder regeneration.

869 The novel biocomposite enhanced urinary bladder regeneration by inducing smooth muscle regrowth and preventing scar tissue formation – animal model study

869 The novel biocomposite enhanced urinary bladder regeneration by inducing smooth muscle regrowth and preventing scar tissue formation – animal model study

Cotransplantation with specific populations of spina bifida bone marrow stem/progenitor cells enhances urinary bladder regeneration

Spina bifida (SB) patients afflicted with myelomeningocele typically possess a neurogenic urinary bladder and exhibit varying degrees of bladder dysfunction. Although surgical intervention in the form of enterocystoplasty is the current standard of care in which to remedy the neurogenic bladder, it is still a stop-gap measure and is associated with many complications due to the use of bowel as a source of replacement tissue. Contemporary bladder tissue engineering strategies lack the ability to reform bladder smooth muscle, vasculature, and promote peripheral nerve tissue growth when using autologous populations of cells. Within the context of this study, we demonstrate the role of two specific populations of bone marrow (BM) stem/progenitor cells used in combination with a synthetic elastomeric scaffold that provides a unique and alternative means to current bladder regeneration approaches. In vitro differentiation, gene expression, and proliferation are similar among donor mesenchymal stem cells (MSCs), whereas poly(1,8-octanediol-cocitrate) scaffolds seeded with SB BM MSCs perform analogously to control counterparts with regard to bladder smooth muscle wall formation in vivo. SB CD34(+) hematopoietic stem/progenitor cells cotransplanted with donor-matched MSCs cause a dramatic increase in tissue vascularization as well as an induction of peripheral nerve growth in grafted areas compared with samples not seeded with hematopoietic stem/progenitor cells. Finally, MSC/CD34(+) grafts provided the impetus for rapid urothelium regeneration. Data suggest that autologous BM stem/progenitor cells may be used as alternate, nonpathogenic cell sources for SB patient-specific bladder tissue regeneration in lieu of current enterocystoplasty procedures and have implications for other bladder regenerative therapies.

Is a functional urinary bladder attainable through current regenerative medicine strategies?

The concise yet poignant review article by Adamowicz et al. [1] appearing in this issue of the “Central European Journal of Urology” delves into two critical aspects of urinary bladder tissue engineering. The use of appropriate scaffolding material as an architectural foundation for bladder regeneration combined with multipotent stem/progenitor cell populations is paramount to a physiologically functional bladder. The article presents a critical review of the current state of bladder regeneration and its applicability to a variety of bladder based states including bladder cancer.

Stem cell therapy in bladder dysfunction: where are we? And where do we have to go?

To date, stem cell therapy for the bladder has been conducted mainly on an experimental basis in the areas of bladder dysfunction. The therapeutic efficacy of stem cells was originally thought to be derived from their ability to differentiate into various cell types. Studies about stem cell therapy for bladder dysfunction have been limited to an experimental basis and have been less focused than bladder regeneration. Bladder dysfunction was listed in MESH as “urinary bladder neck obstruction”, “urinary bladder, overactive”, and “urinary bladder, neurogenic”. Using those keywords, several articles were searched and studied. The bladder dysfunction model includes bladder outlet obstruction, cryoinjured, diabetes, ischemia, and spinal cord injury. Adipose derived stem cells (ADSCs), bone marrow stem cells (BMSCs), and skeletal muscle derived stem cells (SkMSCs) are used for transplantation to treat bladder dysfunction. The main mechanisms of stem cells to reconstitute or restore bladder dysfunction are migration, differentiation, and paracrine effects. The aim of this study is to review the stem cell therapy for bladder dysfunction and to provide the status of stem cell therapy for bladder dysfunction.

A bilayered hybrid microfibrous PLGA–Acellular matrix scaffold for hollow organ tissue engineering

Various synthetic and natural biomaterials have been used for regeneration of tissues and hollow organs. However, clinical outcome of reconstructive procedures remained challenging due to the lack of appropriate scaffold materials, supporting the needs of various cell types and providing a barrier function required in hollow organs. To address these problems, we have developed a bilayered hybrid scaffold comprising unique traits of polymeric microfibers and naturally derived acellular matrices and tested its potential for hollow organ regeneration in a rat bladder model. Hybrid scaffolds were fabricated by electrospinning of PLGA microfibers directly onto the abluminal surface of a bladder acellular matrix. Stability of this bilayered construct was established using modified spinning technique. The resulting 3-dimensional framework provided good support for growth, attachment and proliferation of primary bladder smooth muscle cells. Histological analysis in vivo at 4 and 8 weeks post implantation, revealed regeneration of bladder tissue structures consisting of urothelium, smooth muscle and collagen rich layers infiltrated with host cells and micro vessels. Furthermore, hybrid scaffolds maintained normal bladder capacity, whereas BAM recipients showed a significant distension of the bladder. These results demonstrate that this adaptable hybrid scaffold supports bladder regeneration and holds potential for engineering of bladder and other hollow organs.

Characterization of the early proliferative response of the rodent bladder to subtotal cystectomy: a unique model of mammalian organ regeneration.

Subtotal cystectomy (STC; surgical removal of ∼75% of the rat urinary bladder) elicits a robust proliferative response resulting in complete structural and functional bladder regeneration within 8-weeks. The goal of these studies was to characterize the early cellular response that mediates this regenerative phenomenon, which is unique among mammalian organ systems. STC was performed on eighteen 12-week-old female Fischer F344 rats. At 1, 3, 5 and 7-days post-STC, the bladder was harvested 2-hours after intraperitoneal injection of bromodeoxyuridine (BrdU). Fluorescent BrdU labeling was quantified in cells within the urothelium, lamina propria (LP), muscularis propria (MP) and serosa. Cell location was confirmed with fluorescently co-labeled cytokeratin, vimentin or smooth muscle actin (SMA), to identify urothelial, interstitial and smooth muscle cells, respectively. Expression of sonic hedgehog (Shh), Gli-1 and bone morphogenic factor-4 (BMP-4) were evaluated with immunochemistry. Three non-operated rats injected with BrdU served as controls. Less than 1% of cells in the bladder wall were labeled with BrdU in control bladders, but this percentage significantly increased by 5-8-fold at all time points post-STC. The spatiotemporal characteristics of the proliferative response were defined by a significantly higher percentage of BrdU-labeled cells within the urothelium at 1-day than in the MP and LP. A time-dependent shift at 3 and 5-days post-STC revealed significantly fewer BrdU-labeled cells in the MP than LP or urothelium. By 7-days the percentage of BrdU-labeled cells was similar among urothelium, LP and MP. STC also caused an increase in immunostaining for Shh, Gli-1 and BMP-4. In summary, the early stages of functional bladder regeneration are characterized by time-dependent changes in the location of the proliferating cell population, and expression of several evolutionarily conserved developmental signaling proteins. This report extends previous observations and further establishes the rodent bladder as an excellent model for studying novel aspects of mammalian organ regeneration.