Bladder Acellular Matrix Graft Research Articles

Sustained release of stromal cell-derived factor-1 alpha from silk fibroin microfiber promotes urethral reconstruction in rabbits.

We developed a stromal cell-derived factor-1 alpha (SDF-1α)-aligned silk fibroin (SF)/three-dimensional porous bladder acellular matrix graft (3D-BAMG) composite scaffold for long-section ventral urethral regeneration and repair in vivo. SDF-1α-aligned SF microfiber/3D-BAMG, aligned SF microfiber/3D-BAMG, and nonaligned SF microfiber/3D-BAMG scaffolds were prepared using electrostatic spinning and wet processing. Adipose-derived stem cell (ADSC) and bone marrow stromal cell (BMSC) migration was assessed in the SDF-1α-loaded scaffolds. Sustained SDF-1α release in vitro and vivo was analyzed using enzyme-linked immunosorbent assay (ELISA) and western blotting, respectively. The scaffolds were used to repair a 1.5 × 1 cm2 ventral urethral defect in male rabbits in vivo. General observation and retrograde urinary tract contrast assessment were used to examine urethral lumen patency and continuity at 1 and 3 months post-surgery. Postoperative rehabilitation was evaluated using histological detection. The composite scaffolds sustained SDF-1α release for over 16 days in vitro. SDF-1α-aligned SF nanofiber promoted regeneration of urethral mucosa, submucosal smooth muscles, and microvasculature, increased cellular proliferation, and reduced collagen deposition. SDF-1α expression was increased in reconstructed urethra at 3 months post-surgery in SDF-1α-aligned SF group. SDF-1α-aligned SF microfiber/3D-BAMG scaffolds may be used to repair and reconstruct long urethral defects because they accelerate urethral regeneration.

Biomaterial-Based Scaffolds as Antibacterial Suture Materials.

Antibacterial scaffolds are highly desirable for the repair and reconstruction of injured soft tissues. However, the direct fabrication of scaffolds with excellent biocompatibility, flexibility, and antibacterial capacity remains a challenge, especially those based on biomaterials. In this study, we report the biomaterial-based antibacterial scaffolds based on regenerated silk fibroin, 2-hydroxypropyltrimethyl ammonium chloride chitosan, and bladder acellular matrix graft by blend and coaxial electrospinning. This approach eliminated the use of organic solvents and inorganic nanoparticles, ensuring greater clinical safety, mimicking physiological extracellular matrix structures, and the required softness for a suture material. Thus, the scaffold obtained in this study exhibited excellent biocompatibility, the required mechanical characteristics, and excellent antibacterial capacity. The rate of bacterial elimination of Staphylococcus aureus and Escherichia coli reached up to 99.5 and 98.3%, respectively. The scaffold design favored cell growth and proliferation and resulted in the significant promotion of repair and reconstruction of the urethra, indicating that it can be an ideal antibacterial suture material for soft tissue restoration.

Understanding the role of mesenchymal stem cells in urinary bladder regeneration\u2014a preclinical study on a porcine model

BackgroundThe tissue engineering of urinary bladder advances rapidly reflecting clinical need for a new kind of therapeutic solution for patients requiring urinary bladder replacement. Majority of the bladder augmentation studies have been performed in small rodent or rabbit models. Insufficient number of studies examining regenerative capacity of tissue-engineered graft in urinary bladder augmentation in a large animal model does not allow for successful translation of this technology to the clinical setting. The aim of this study was to evaluate the role of adipose-derived stem cells (ADSCs) in regeneration of clinically significant urinary bladder wall defect in a large animal model.MethodsADSCs isolated from a superficial abdominal Camper’s fascia were labeled with PKH-26 tracking dye and subsequently seeded into bladder acellular matrix (BAM) grafts. Pigs underwent hemicystectomy followed by augmentation cystoplasty with BAM only (n = 10) or BAM seeded with autologous ADSCs (n = 10). Reconstructed bladders were subjected to macroscopic, histological, immunofluoresence, molecular, and radiological evaluations at 3 months post-augmentation.ResultsSixteen animals (n = 8 for each group) survived the 3-month follow-up without serious complications. Tissue-engineered bladder function was normal without any signs of post-voiding urine residual in bladders and in the upper urinary tracts. ADSCs enhanced regeneration of tissue-engineered urinary bladder but the process was incomplete in the central graft region. Only a small percentage of implanted ADSCs survived and differentiated into smooth muscle and endothelial cells.ConclusionsThe data demonstrate that ADSCs support regeneration of large defects of the urinary bladder wall but the process is incomplete in the central graft region. Stem cells enhance urinary bladder regeneration indirectly through paracrine effect.

Post-transcriptional suppression of TIMP-1 in epithelial-differentiated adipose-derived stem cells seeded bladder acellular matrix grafts reduces urethral scar formation

Prevention of fibrosis and urethral scar formation is critical for a successful urethral reconstruction. We have previously shown that epithelial-differentiated adipose-derived stem cells (EASC) seeded bladder acellular matrix grafts (BAMG) can be used for urethral reconstruction. We have also shown that suppression of tissue inhibitor of metalloproteinases-1 (TIMP-1) reduces epithelial–mesenchymal transition in urethral fibroblasts in vitro and in vivo. However, it is unknown whether suppression of TIMP-1 in EASC seeded BAMG may benefit urethral reconstruction through inhibition of fibrosis. Here, we addressed this question. In a rabbit substitution urethroplasty model, we found that E-cadherin + EASC resulted in wider urethral caliber and formation of less urethral scar tissue, compared to non-purified EASC. Bioinformatics study showed that among all TIMP-1-targeting microRNAs (miRNAs), miR-365 is a conserved one in rabbits and humans, and functionally inhibits TIMP-1 protein translation. MiR-365-transduced E-cadherin + EASC seeded BAMG further reduced fibrosis and increased urethral caliber width during urethral reconstruction in rabbits, compared to E-cadherin + EASC seeded BAMG. Together, these data suggest that EASC seeded BAMG method for urethral reconstruction could be further improved through purification of EASC by E-cadherin and through post-transcriptional inhibition of TIMP-1 via miR-365 in EASC.

Adipose-derived stem cells-seeded bladder acellular matrix graft-silk fibroin enhances bladder reconstruction in a rat model.

The unfavourable clinical outcomes of host cell-seeded scaffolds for bladder augmentation warrant improved bioactive biomaterials. This study aimed to examine the feasibility of adipose-derived stem cells (ASCs)-seeded bilayer bladder acellular matrix graft (BAMG)-silk fibroin (SF) scaffold in enhancing bladder reconstruction. Sprague Dawley rats were randomly divided into three groups: the BAMG-SF-ASCs group, the acellular BAMG-SF group and the cystotomy group. The BAMG-SF-ASCs group was sampled at 2, 4 and 12 weeks, and compared with the other groups at 12 weeks. In the BAMG-SF-ASCs group, the normal bladder contour was reformed similar to that in the cystotomy group, with abundant urothelium and smooth muscle regeneration, as well as a suitable scaffold degradation speed, and trivial fibrosis and inflammation. The ASCs seeded in BAMG-SF were maintained in the regenerated region during the 12-week experimental period and significantly enhanced the vessel density, nerve regeneration and bladder function compared with acellular BAMG-SF. In addition, the BAMG-SF-ASCs group presented elevated levels of SDF-1α, VEGF and their receptors, with an obvious increase in ERK 1/2 phosphorylation. BAMG-SF is a promising biomaterial for ASCs seeding to facilitate bladder augmentation and demonstrated an enhanced angiogenic potential possibly related to the SDF-1α/CXCR4 pathway via ERK 1/2 activation.

The morphological regeneration and functional restoration of bladder defects by a novel scaffold and adipose-derived stem cells in a rat augmentation model

BackgroundDue to the multilineage differentiation ability and paracrine role of adipose-derived stem cells (ASCs) for bladder defect repair, various scaffolds have been applied in combination with ASCs to promote bladder regeneration and restore bladder function. However, the low survival rate of ASCs and the difficulty of promoting bladder functional recovery are still unsolved. To explore these problems, we investigated the feasibility of a novel scaffold seeded with ASCs in a rat model of bladder augmentation.MethodsA novel autologous myofibroblast (AM)-silk fibroin (SF) scaffold was harvested after subcutaneously prefabricating the bladder acellular matrix grafts (BAMG) and SF by removing the BAMG. The AM-SF scaffolds were then seeded with ASCs (AM-SF-ASCs). Fifty percent supratrigonal cystectomies were performed followed by augmenting the cystectomized defects with AM-SF scaffolds or AM-SF-ASCs. The histological and functional assessments of bladders were performed 2, 4, and 12 weeks after surgery while the ASCs were tracked in vivo.ResultsFor bladder tissue regeneration, immunofluorescence analysis revealed that AM-SF-ASCs (the experimental group) promoted better morphological regeneration of the urothelium, vessels, bladder smooth muscle, and nerve than AM-SF scaffolds (the control group). Regarding functional restoration, the AM-SF-ASC group exhibited higher bladder compliance and relatively normal micturition pattern compared to the AM-SF group. In addition, a certain number of surviving ASCs could be found in vivo 12 weeks after implantation, and some of them had differentiated into smooth muscle cells.ConclusionsThe AM-SF scaffolds with ASCs could rapidly promote bladder morphological regeneration and improved bladder urinary function. In addition, the bag-shaped structure of the AM-SF scaffold can improve the survival of ASCs for at least 12 weeks. This strategy of AM-SF-ASCs has a potential to repair large-scale bladder defects in the clinic in the future.

MP94-06 MORPHOLOGICAL AND FUNCTIONAL RESTORATION COMPARISON BETWEEN A NOVEL BILAYER CHITOSAN AND BLADDER ACELLULAR MATRIX GRAFT AS SCAFFOLDS IN A RAT BLADDER AUGMENTATION MODEL.

You have accessJournal of UrologyBladder & Urethra: Anatomy, Physiology & Pharmacology II1 Apr 2017MP94-06 MORPHOLOGICAL AND FUNCTIONAL RESTORATION COMPARISON BETWEEN A NOVEL BILAYER CHITOSAN AND BLADDER ACELLULAR MATRIX GRAFT AS SCAFFOLDS IN A RAT BLADDER AUGMENTATION MODEL. Dongdong Xiao, Qiong Wang, and Mujun LU Dongdong XiaoDongdong Xiao More articles by this author , Qiong WangQiong Wang More articles by this author , and Mujun LUMujun LU More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.2909AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Confronted by the limitations of current biomaterials applied in bladder augmentation and urgent clinic needs of alternatives for traditional enterocystoplasty, this study compared the performance of a novel asymmetric bilayer chitosan scaffold with conventional bladder acellular matrix graft (BAMG) in the purpose to assess the feasibility of this strategy as a supplement or replacement for current bladder biomaterials. METHODS Twenty-four 4-week-old male Sprague-Dawley rats were randomly divided into 3 groups which were subjected to augmentation cystoplasty with BAMG, bilayer chitosan scaffolds and sham operation respectively, with 8 rats in each group. At the time-points of 21 days and 70 days post-implantation, basic epidemiological data, morphological, histological (hematoxylin and eosin, Masson's trichrome and immunofluorescence analyses) and functional evaluations were carried out to compare bladder regeneration comprehensively. RESULTS Bilayer chitosan scaffold exhibited an excellent combination of mechanical strength and flexibility, with minimal fibrosis and contracture after integrated into bladder defect. All rats survived during the experimental period, recovered to normal activities and were able to void spontaneously without significant difference in body weight, except that one rat in BAMG group (70 days group) died of urinary ascites within first week post-op. It was proved that bilayer chitosan scaffold had a better performance in both histological staining and morphological analyses of cystography. While the de novo cytokeratin positive urothelia appeared more abundant in BAMG group than chitosan group when compared to control group, the regeneration of a-smooth muscle actin (a-SMA) and SM22-a positive smooth muscle bundles, NeuN positive neural buttons, the mean number of CD31 positive vessels were more favorable in chitosan group than BAMG group, but still did not catch up with the normal level. The mean diameter of CD31 positive vessels revealed that the neo-vessels in BAMG and chitosan group were relatively immature. For both BAMG and chitosan groups, urodynamic analyses demonstrated that the bladder compliance was improved after augmentation, and the interval void cycle time, void volume and bladder capacity were elevated correspondingly, while the peak void pressure of BAMG was exceptionally high. CONCLUSIONS The asymmetric bilayer chitosan scaffold displayed a high potential in facilitating defect regeneration in the rat model of bladder augmentation, which still need further modifications in enhancing the regeneration of urothelia, accelerating re-innervation and promoting neo-angiogenesis. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e1247 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Dongdong Xiao More articles by this author Qiong Wang More articles by this author Mujun LU More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

203 - Morphological and functional restoration comparison between a novel bilayer chitosan and bladder acellular matrix graft as scaffolds in a rat bladder augmentation model

203 - Morphological and functional restoration comparison between a novel bilayer chitosan and bladder acellular matrix graft as scaffolds in a rat bladder augmentation model

Comparison of morphological and functional restoration between asymmetric bilayer chitosan and bladder acellular matrix graft for bladder augmentation in a rat model

Asymmetric bilayer chitosan promoted bladder reconstruction with enhanced smooth muscle regeneration and angiogenesis, and functional restoration with augmented bladder capacity.

The Use of Vascular Endothelial Growth Factor with Silk Fibroin Scaffolds and Bladder Acellular Matrix Grafts to Support Bladder Reconstruction in Rabbit Model

The Use of Vascular Endothelial Growth Factor with Silk Fibroin Scaffolds and Bladder Acellular Matrix Grafts to Support Bladder Reconstruction in Rabbit Model

279 Bladder acellular matrix grafts seeded with adipose-derived stem cells and incubated intraperitoneally promote the regeneration of bladder smooth muscle in a rat model of bladder augmentation

279 Bladder acellular matrix grafts seeded with adipose-derived stem cells and incubated intraperitoneally promote the regeneration of bladder smooth muscle in a rat model of bladder augmentation

Bladder Acellular Matrix Grafts Seeded with Adipose-Derived Stem Cells and Incubated Intraperitoneally Promote the Regeneration of Bladder Smooth Muscle and Nerve in a Rat Model of Bladder Augmentation.

The objective of this study was to investigate the feasibility of bladder acellular matrix grafts (BAMGs) seeded with adipose-derived stem cells (ASCs) followed by intraperitoneal incubation for bladder reconstruction in a rat model of bladder augmentation, and to explore the underlying mechanism. Autologous CM-DiI-labeled ASC-seeded (experimental group) and unseeded (control group) BAMGs were incubated in the peritoneum of male rats for 2 weeks and then harvested for bladder augmentation. Histological analysis of the incubated BAMGs revealed numerous cells growing in homogeneous collagen bundles in both groups. In the control BAMGs, these cells were mesenchyme derived, while in the ASC-seeded BAMGs, myofibroblasts and mesothelial cells were found inside and on the surface of the scaffold, respectively. Immunofluorescence analysis demonstrated that some of the myofibroblasts were transdifferentiated from the ASCs after 2 weeks of intraperitoneal incubation. The greater bladder capacity was found in the experimental group than the control group both 4 and 14 weeks postoperatively. Histological analysis revealed that the entire urothelium regenerated well both in the experimental group and the control group without significant difference 4 weeks and 14 weeks postoperatively. From the quantitative data of immunohistochemical and immunofluorescence staining, the smooth muscle cells (SMCs) regenerated significantly better in the experimental group than the control group both 4 weeks and 14 weeks postoperatively. Also significantly more nerve cells were found in the experimental group 14 weeks postoperatively. At 4 weeks postoperatively, the immunofluorescence double staining revealed that some SMCs in the BAMG were transdifferentiated from the implanted ASCs, but no CM-DiI labeling of ASCs was detected 14 weeks postoperatively. Taken together, our results demonstrate that ASC-seeded and peritoneally incubated BAMGs promote not only the morphological regeneration of the bladder smooth muscle and nerve, but also the bladder capacity, which indicates their potential for bladder regeneration.

Time-dependent bladder tissue regeneration using bilayer bladder acellular matrix graft-silk fibroin scaffolds in a rat bladder augmentation model

With advances in tissue engineering, various synthetic and natural biomaterials have been widely used in tissue regeneration of the urinary bladder in rat models. However, reconstructive procedures remain insufficient due to the lack of appropriate scaffolding, which should provide a waterproof barrier function and support the needs of various cell types. To address these problems, we have developed a bilayer scaffold comprising a porous network (silk fibroin [SF]) and an underlying natural acellular matrix (bladder acellular matrix graft [BAMG]) and evaluated its feasibility and potential for bladder regeneration in a rat bladder augmentation model. Histological (hematoxylin and eosin and Masson’s trichrome staining) and immunohistochemical analyses demonstrated that the bilayer BAMG-SF scaffold promoted smooth muscle, blood vessel, and nerve regeneration in a time-dependent manner. At 12weeks after implantation, bladders reconstructed with the BAMG-SF matrix displayed superior structural and functional properties without significant local tissue responses or systemic toxicity. These results demonstrated that the bilayer BAMG-SF scaffold may be a promising scaffold with good biocompatibility for bladder regeneration in the rat bladder augmentation model.

Intraperitoneal incubation of bladder acellular matrix grafts improves bladder smooth muscle regeneration via neovascularization

The objective of this study was to investigate whether intraperitoneal incubation improves the regenerative capacity of bladder acellular matrix grafts (BAMGs) in a rat model of bladder augmentation. After 2 weeks of incubation in the peritoneum of male rats, BAMG flaps with vascular pedicles were harvested for autologous bladder augmentation. As the control, BAMGs were directly used for bladder augmentation without intraperitoneal incubation. Histological analyses of the incubated BAMGs demonstrated extensive cell growth and vasculature in homogeneous collagen bundles. The cells were positive for vimentin and negative for α-smooth muscle actin and pan-cytokeratin AE1/AE3. Cystography revealed smoother contours of the augmented bladders in the incubated group at 4 and 12 weeks postoperatively. However, the bladder capacity was not significantly different between the two groups. In both groups, the entire urothelium regenerated well without obvious differences. At both time points, compared with the control group, increased numbers of smooth muscle cells (SMCs) and blood vessels were found in the incubated group. At 12 weeks, the SMCs in the incubated group were more similar to those in the native smooth muscle fiber bundles of the bladder. Taken together, our results demonstrated that BAMGs preincubated in the peritoneum promote the regeneration of bladder smooth muscle via neovascularization in a rat bladder augmentation model.

Bladder Acellular Matrix Graft Reinforced Silk Fibroin Composite Scaffolds Loaded VEGF with Aligned Electrospun Fibers in Multiple Layers.

Bombyx mori silk is of great interest to people for its outstanding mechanical and biological properties. However, the traditional electrospun regenerated silk fibroin (RSF) scaffolds from aqueous solution were weak and had limited applications. This study was to fabricate reinforced scaffolds with well-aligned RSF fibers electrospun on a layer of native extracellular matrix, bladder acellular matrix graft (BAMG). The silk fibroin fibers were well-aligned as a grill in multiple layers. Both the BAMG and the grill structure significantly improved the tensile properties and suture retention of the composite scaffolds, which can be sutured well with tissue during implantation. In vitro assay indicates that the scaffolds had a good biocompatibility. Porcine iliac endothelial cells (PIECs) attached and proliferated well on the vascular endothelial growth factor (VEGF) loaded scaffolds compared with those without VEGF. Moreover, the grill-like structure guides PIECs well along the aligned fiber.

1079 Intraperitoneal prefabricated bladder acellular matrix grafts to improve bladder smooth muscle regeneration and neovascularization in a rat model

1079 Intraperitoneal prefabricated bladder acellular matrix grafts to improve bladder smooth muscle regeneration and neovascularization in a rat model

179 Human umbilical mesenchymal stem cells-seeded bladder acellular matrix grafts for reconstruction of bladder defects in a canine model

179 Human umbilical mesenchymal stem cells-seeded bladder acellular matrix grafts for reconstruction of bladder defects in a canine model

Epithelial-Differentiated Adipose-Derived Stem Cells Seeded Bladder Acellular Matrix Grafts for Urethral Reconstruction: An Animal Model

The limited amount of available epithelial tissue is considered a main cause of the high rate of urethral reconstruction failures. The aim of this study was to investigate whether epithelial-differentiated rabbit adipose-derived stem cells (Epith-rASCs) could play a role of epithelium in vivo functionally and be a potential substitute of urothelium. Substitution urethroplasty was performed to repair an anterior urethral defect in male New Zealand rabbits using Epith-rASCs seeded bladder acellular matrix grafts (BAMGs) after 5-bromo-2'-deoxyuridine (BrdU) labeling, based on the in vitro epithelial induction system we previously described. Urethroplasty with cell-free BAMGs and with undifferentiated rASCs (Und-rASCs) seeded BAMGs were performed as controls. After surgery, a notable amelioration of graft contracture and recovery of urethral continuity were observed in the Epith-rASCs/BAMG group by retrograde urethrograms and macroscopic inspection. Immunofluorescence revealed that the BrdU-labeled Epith-rASCs/Und-rASCs colocalized with cytokeratin 13 or myosin. Consistent with the results of western blotting, at early postimplantation stage, the continuous epithelial layer with local multilayered structure was observed in the Epith-rASCs/BAMG group, whereas no significant growth and local monolayer growth profile of epithelial cells were observed in the BAMG and Und-rASCs/BAMG group, respectively. The results showed that Epith-rASCs could serve as a potential substitute of urothelium for urethral tissue engineering and be available to prevent lumen contracture and subsequent complications including recurrent stricture.

Correction: Human Umbilical Mesenchymal Stem Cells-Seeded Bladder Acellular Matrix Grafts for Reconstruction of Bladder Defects in a Canine Model

Correction: Human Umbilical Mesenchymal Stem Cells-Seeded Bladder Acellular Matrix Grafts for Reconstruction of Bladder Defects in a Canine Model

Human Umbilical Mesenchymal Stem Cells-Seeded Bladder Acellular Matrix Grafts for Reconstruction of Bladder Defects in a Canine Model

BackgroundThe goal of this study was to explore the feasibility of utilizing human umbilical mesenchymal stem cells (HUMSCs)-seeded Bladder acellular matrix graft (BAMG) for bladder reconstruction in a canine model.Methodology/Principal FindingsHUMSCs were isolated from newborn umbilical cords and identified by flow cytometry. Partial cystectomy was performed in the experimental and control group. Bladder defects were repaired with HUMSCs-BAMG in the experimental group and repaired with unseeded-BAMG in control group. The implanted grafts were harvested after surgery. H&E and immunohistochemistry staining were performed to evaluate the regeneration of the bladder defect. Primary cultured HUMSCs displayed typical fibroblast morphology with spindle-shaped. Flow cytometry indicated that these cells were positive for CD105 (97.3%) and CD44 (99%), but negative for CD34 (2.8%), CD31 (2.1%), and CD45 (1.7%). Immunohistochemistry staining showed that a multilayered urothelium and well-developed smooth muscle were observed at 12 weeks in experiment group. In contrast, multilayered urothelial tissues were also observed at 12 weeks in group B, but well-developed smooth muscle bundles were observed.Conclusions/SignificanceOur preliminary results demonstrate that UMSC-seeded BAMGs are superior to unseeded BAMGs to promote the regeneration of bladder defects. Our findings indicated that HUMSCs may be a potential cell source for bladder tissue engineering.