Urinary bladder matrix scaffold improves the impact of adipose-mesenchymal stem cells on the function and structure of transplanted rat ovaries.

Ovarian transplantation presents significant advantages for the preservation of female fertility. Nonetheless, a substantial number of follicles are apoptosis during the process of ovarian tissue transplantation as a result of ischemic conditions. This study aimed to assess whether adipose-derived mesenchymal stem cells combined with urinary bladder matrix (ADSC/UBM) confer a greater therapeutic benefit compared to ADSCs alone. To achieve this, ADSC/UBM was applied during the autotransplantation of rat ovaries. Thirty rats were divided into five sets of six: the untreated control group (Normal), the oophorectomy group, the autograft group, the autograft + ADSCs group (ADSC), and the autograft + ADSC/UBM group (ADSC/UBM). After transplantation, the number of follicles in the ADSC/UBM group was significantly higher than that in the autograft group. Angiogenesis was enhanced following ADSC/UBM transplantation. Follicle-stimulating hormone (FSH) levels were significantly lower, and Anti-Müllerian hormone (AMH) levels were significantly higher in rats in the ADSC/UBM group than in the Autograft group. The apoptosis rate in the ADSC/UBM group decreased. The estrous cycle in the ADSC/UBM group recovered more quickly than the ADSC group. The data indicate that UBM improves ADSC retention in graft ovaries and aids in permanently restoring ovarian function, making ADSC/UBM a promising option for ovarian transplantation.

Extracellular Matrices as Bioactive Materials for In Situ Tissue Regeneration.

Bioactive materials based on a nature-derived extracellular matrix (NECM) represent a category of biomedical devices with versatile therapeutic applications in the realms of tissue repair and engineering. With advancements in decellularization technique, the inherent bioactive molecules and the innate nano-structural and mechanical properties are preserved in three-dimensional scaffolds mainly composed of collagens. Techniques such as electrospinning, three-dimensional printing, and the intricate fabrication of hydrogels are developed to mimic the physical structures, biosignalling and mechanical cues of ECM. Until now, there has been no approach that can fully account for the multifaceted properties and diverse applications of NECM. In this review, we introduce the main proteins composing NECMs and explicate the importance of them when used as therapeutic devices in tissue repair. Nano-structural features of NECM and their applications regarding tissue repair are summarized. The origins, degradability, and mechanical property of and immune responses to NECM are also introduced. Furthermore, we review their applications, and clinical features thereof, in the repair of acute and chronic wounds, abdominal hernia, breast deformity, etc. Some typical marketed devices based on NECM, their indications, and clinical relevance are summarized.

Use of a dynamic tissue system and biological xenograft in complex traumatic wound closure.

OBJECTIVE: Asymmetrical dimensions and nonlinear margins of a multilayered traumatic wound often preclude healing via primary intention. We present the case of an otherwise healthy 21-year-old male who sustained trauma following a boating accident. METHOD: The patient sustained three lacerations to the posterior thighs from the boat propeller. The most extensive wound measured 25×10×6cm of muscle extrusion with a divot fracture involving the posterior femur. RESULTS: Primary closure and restoration of muscle biomechanics was achieved using a combination of a dynamic tissue system (DTS) and porcine urinary bladder matrix (PUBM) xenograft. After 24 days of treatment in hospital, the patient was discharged without the need for home health, outpatient wound care, or ongoing negative pressure wound therapy. The patient recovered full function of the legs and was cleared for participation in all activities. CONCLUSION: This complex traumatic boat propeller injury presented many challenges, including a transverse orientation on the extremity, degree of muscle injury/extrusion, and significant soft tissue loss. The combined application of a DTS with PUBM biological xenograft achieved a primary myocutaneous closure without the need for skin graft or flap reconstruction by plastic surgery.

Urinary bladder matrix for lower extremity split-thickness skin graft donor site.

Split-thickness skin grafts (STSG) are commonly used to treat soft-tissue defects. Harvesting a STSG creates an additional partial thickness wound at the donor site which must be managed. Many dressings are commercially available for the management of STSG donor sites; however, there is no evidence-based consensus on optimal dressing for site management. Urinary bladder matrix (UBM) is an extracellular matrix that acts as a structural support for tissue remodeling and provides molecular components for repair. Common clinical applications of UBM include coverage of deep wounds, burns, and irradiated skin. Skin grafting from the lower extremities poses a challenge due to the increased dermal tension. UBM-based reconstruction is an alternative method of managing lower extremity skin graft donor sites. This case study demonstrates the use of UBM in the reconstruction of a STSG donor site of the anterolateral thigh, which resulted in satisfactory healing, no pain, and excellent cosmetic and functional outcomes.

Crush injury with significant soft tissue loss managed utilising biological and dynamic tissue systems: a case study.

Major traumatic crush injuries are difficult to manage, with high morbidity, requiring prolonged, complex treatment with many procedures. Free-flap reconstruction is often used yet full functionality still may not be regained. In this case study of a traumatic crush injury of the anterior distal tibia, ankle and foot of a 48-year-old male patient, we opted for an alternative management strategy using a combination of a dynamic tissue system (DTS) and biological xenografts (porcine urinary bladder matrix and a multi-tissue platform). The DTS was kept in place in an outpatient setting for four weeks postoperatively and removed after that time. At the 3-month follow-up, the wound was significantly smaller at about 15% of the original size. The wound healed completely before 6-month follow-up. Our patient's traumatic crush injury was successfully healed using an alternative management strategy, DTS and biologic xenografts.

Characterizing the inherent activity of urinary bladder matrix for adhesion, migration, and activation of fibroblasts as compared with collagen-based synthetic scaffold.

The mechanism of action underlying the intriguing prominent bioactivity of urinary bladder matrix (UBM) for in situ tissue regeneration of soft tissue defects remains to be elucidated. It is speculated that the activity of UBM for cell adhesion, migration, and activation is inherent. The bioactivity of UBM for in situ tissue regeneration and its relation with the structure and intact soluble components of UBM were investigated in comparison to a collagen-based scaffold, PELNAC (PEL). We isolated the soluble component of the two materials with urea buffer, and evaluated the respective effect of these soluble components on the in vitro adhesion and migration of L929 fibroblasts. The spatiotemporal pattern of endogenous-cell ingrowth into the scaffolds and cell activation were investigated using a model of murine subcutaneous implantation. UBM is more capable of promoting the adhesion, migration, and proliferation of fibroblasts than PEL in a serum-independent manner. In vivo, as compared with PEL, UBM exhibits significantly enhanced activity for fast endogenous cell ingrowth and produces a more prominent pro-regenerative and pro-remodeling microenvironment by inducing the expression of TGF-ß1, VEGF, MMP-9, and murine type I collagen. Overall, our results suggest the prominent bioactivity of UBM for in situ tissue regeneration is inherent.

Outcome of a novel porcine-derived UBM/SIS composite biological mesh in a rabbit vaginal defect model.

INTRODUCTION AND HYPOTHESIS: To investigate the tissue reactions of a novel porcine-derived urinary bladder matrix/small intestinal submucosa (UBM/SIS) biological mesh and SIS mesh implanted in a rabbit vaginal defect model. METHODS: Thirty-two rabbits were implanted with UBM/SIS mesh (Group A) and SIS mesh (Group B), respectively. Rabbits were sacrificed at 7, 14, 60, and 180 days after implantation. The tensile strength, elongation at break, and elastic modulus of the tissue were measured using biomechanical methods. The inflammatory response, cell infiltration, vascularization, and collagen fibers were observed. RESULTS: Compared with Group B, the tensile strength and elongation at break of group A was higher at 14, 60, and 180 days. The elastic modulus of group A was lower at 180 days. Inflammatory response of group A was milder at 14, 60, and 180 days. There was more cell infiltration in group A at 7 and 14 days. Vascularization was higher in group A at 7 days and 14 days. The order of collagen in group A was better at 14, 60, and 180 days. The proportion of thick red fibers in both groups showed an increasing trend. At 14 days, group A had more thick red fibers. CONCLUSIONS: The novel UBM/SIS composite mesh had a milder inflammatory response; earlier induction of cell infiltration, angiogenesis, and collagen regeneration. Collagen fibers had a better order. It has a higher tensile strength and greater elongation at break, and can be used as a potential material for the treatment of pelvic organ prolapse.

Two surgeons' collaboration to close an extreme open abdomen with loss of domain utilizing the abdominal dynamic tissue system and porcine urinary bladder matrix.

Acute open abdomen with loss of domain is an extremely difficult surgical scenario, and secondary complications are common. This case describes a 33-year-old woman who initially underwent an elective, laparoscopic endometrioma resection during which a complete iatrogenic transection of the left ureter and part of the sigmoid mesentery occurred. After discharge 5 days later, she was immediately readmitted for worsening abdominal pain. During the emergency abdominal reexploration, an ischemic, perforated sigmoid colon was removed and large volume paracentesis was performed due to fecal contamination. Nine additional reexplorations over 2 months resulted in an extreme acute open abdomen with loss of domain. Viscera was protected with negative pressure wound therapy, but primary myofascial closure was not feasible. Through surgical collaboration between two institutions, an abdominal dynamic tissue system was installed, which achieved primary myofascial closure 31 days after installation. Nine days later, complete wound closure utilizing porcine urinary bladder matrix was accomplished. This case highlights the successful achievement of primary myofascial closure and complete wound healing without a surgical site infection or hernia development in this heavily contaminated abdomen using dynamic tissue system biomechanics with porcine urinary bladder matrix biologics.

Effect of naturally derived surgical hemostatic materials on the proliferation of A549 human lung adenocarcinoma cells.

Hemostatic materials are generally applied in surgical operations for cancer, but their effects on the growth and recurrence of tumors are unclear. Herein, three commonly used naturally derived hemostatic materials, gelatin sponge, Surgicel (oxidized regenerated cellulose), and biopaper (mixture of sodium hyaluronate and carboxymethyl chitosan), were cocultured with A549 human lung adenocarcinoma cells in vitro. Furthermore, the performance of hemostatic materials and the tumorigenicity of the materials with A549 â€‹cells were observed after subcutaneous implantation into BALB/c mice. The in vitro results showed that biopaper was dissolved quickly, with the highest cell numbers at 2 and 4 days of culture. Gelatin sponges retained their structure and elicited the least cell infiltration during the 2- to 10-day culture. Surgicel partially dissolved and supported cell growth over time. The in vivo results showed that biopaper degraded rapidly and elicited an acute Th1 lymphocyte reaction at 3 days after implantation, which was decreased at 7 days after implantation. The gelatin sponge resisted degradation and evoked a hybrid M1/M2 macrophage reaction at 7-21 days after implantation, and a protumor M2d subset was confirmed. Surgicel resisted early degradation and caused obvious antitumor M2a macrophage reactions. Mice subjected to subcutaneous implantation of A549 â€‹cells and hemostatic materials in the gelatin sponge group had the largest tumor volumes and the shortest overall survival (OS), while the Surgicel and the biopaper group had the smallest volumes and the longest OS. Therefore, although gelatin sponges exhibited cytotoxicity to A549 â€‹cells in vitro, they promoted the growth of A549 â€‹cells in vivo, which was related to chronic M2d macrophage reaction. Surgicel and biopaper inhibited A549 â€‹cell growth in vivo, which is associated with chronic M2a macrophage reaction or acute Th1 lymphocyte reaction.

Production and Preparation of Porcine Urinary Bladder Matrix (UBM) for Urinary Bladder Tissue-Engineering Purposes.

Surgical repair for the end stage bladder disease utilises vascularised, autogenous and mucus-secreting gastrointestinal tissue to replace the diseased organ or to augment inadequate bladder tissue. Post-operatively, the compliance of the bowel is often enough to restore the basic shape, structure and function of the urinary bladder; however, lifelong post-operative complications are common. Comorbidities that result from interposition of intestinal tissue are metabolic and/or neuromechanical, and their incidence approaches 100%. The debilitating comorbidities and complications associated with such urological procedures may be mitigated by the availability of alternative, tissue-engineered, animal-derived extracellular matrix (ECM) scaffolds such as porcine urinary bladder matrix (UBM). Porcine UBM is a decellularized biocompatible, biodegradable biomaterial derived from the porcine urinary bladder. This chapter aims to describe the production and preparation techniques for porcine UBM for urinary bladder regenerative purposes.

Human Bronchial Epithelial Cell Growth on Homologous Versus Heterologous Tissue Extracellular Matrix.

BACKGROUND: Extracellular matrix (ECM) bioscaffolds produced by decellularization of source tissue have been effectively used for numerous clinical applications. However, decellularized tracheal constructs have been unsuccessful due to the immediate requirement of a functional airway epithelium on surgical implantation. ECM can be solubilized to form hydrogels that have been shown to support growth of many different cell types. The purpose of the present study is to compare the ability of airway epithelial cells to attach, form a confluent monolayer, and differentiate on homologous (trachea) and heterologous (urinary bladder) ECM substrates for potential application in full tracheal replacement. MATERIALS AND METHODS: Porcine tracheas and urinary bladders were decellularized. Human bronchial epithelial cells (HBECs) were cultured under differentiation conditions on acellular tracheal ECM and urinary bladder matrix (UBM) bioscaffolds and hydrogels and were assessed by histology and immunolabeling for markers of ciliation, goblet cell formation, and basement membrane deposition. RESULTS: Both trachea and urinary bladder tissues were successfully decellularized. HBEC formed a confluent layer on both trachea and UBM scaffolds and on hydrogels created from these bioscaffolds. Cells grown on tracheal and UBM hydrogels, but not on bioscaffolds, showed positive-acetylated tubulin staining and the presence of mucus-producing goblet cells. Collagen IV immunolabeling showed basement membrane deposition by these cells on the surface of the hydrogels. CONCLUSIONS: ECM hydrogels supported growth and differentiation of HBEC better than decellularized ECM bioscaffolds and show potential utility as substrates for promotion of a mature respiratory epithelium for regenerative medicine applications in the trachea.

Material Characterisation and Stratification of Conjunctival Epithelial Cells on Electrospun Poly(ε-Caprolactone) Fibres Loaded with Decellularised Tissue Matrices.

The conjunctiva, an under-researched yet incredibly important tissue, plays key roles in providing protection to the eye and maintaining homeostasis of its ocular surface. Multiple diseases can impair conjunctival function leading to severe consequences that require surgical intervention. Small conjunctival defects can be repaired relatively easily, but larger defects rely on tissue grafts which generally do not provide adequate healing. A tissue engineering approach involving a biomaterial substrate capable of supporting a stratified epithelium with embedded, mucin-secreting goblet cells offers a potential solution. As a first step, this study aimed to induce stratification of human conjunctival epithelial cells cultured on electrospun scaffolds composed from poly(ε-caprolactone) (PCL) and decellularised tissue matrix (small intestinal submucosa (SIS) or urinary bladder matrix (UBM)) and held at the air/liquid interface. Stratification, up to 5 cell layers, occurred more frequently on scaffolds containing PCL + UBM. Incorporation of these decellularised tissue matrices also impacted material properties, with significant changes occurring to their fibre diameter, tensile properties, and chemical composition throughout the scaffold structure compared to PCL alone. These matrix containing scaffolds warrant further long-term investigation as a potential advanced therapy medicinal product for conjunctiva repair and regeneration.

Novel Use of a Porcine Bladder Extracellular Matrix Scaffold to Treat Postoperative Seroma in a Total Knee Arthroplasty Patient.

Seroma formation in a knee arthroplasty surgery is a rare complication. When seromas occur, they act as a nidus for bacterial growth and create an optimal environment for surgical site infections. In this case report, a 52-year-old woman presented with a seroma after multiple revision operations on the left knee. Owing to multiple failures of standard irrigation and drainage procedures to resolve the seroma, an orthoplastic colleague was consulted. Over five-and-a-half months, the patient underwent multiple procedures that failed to treat the seroma. However, in a final exploratory procedure, 3000 mg of urinary bladder matrix and negative pressure wound vacuum were placed. Seven months after the intervention, the patient had complete resolution.

Treatment with a Urinary Bladder Matrix Alters the Innate Host Response to Pneumonia Induced by Escherichia coli.

Escherichiacoli has become the prominent cause of nosocomial pneumonia in recent years. In the meantime, some strains of E. coli have developed resistance to commonly used antibacterial drugs. The urinary bladder matrix (UBM) is a biologically derived scaffold material that has been used to promote site-appropriate tissue remodeling in a variety of body systems, partially through the modulation of the innate immune response. In this study, we seek to determine UBM efficacy in preventing bacterial pneumonia in mouse lungs using the Gram-negative bacterial strain E. coli. Our results show that the UBM prevented bacterial biofilm formation in both abiotic and biotic conditions through experimentation on polystyrene plates and culture on the apical surface of differentiated airway epithelial cells. Intratracheal treatment with UBM led to host protection from E. coli-induced respiratory infection in a murine pneumonia model. Transcriptomic analysis revealed the involvement of the enhanced host immune response in UBM-treated mice. Additionally, UBM-treated macrophages had an increased iNOS expression and enhanced phagocytosis activity. Therefore, the protection against E. coli-induced infection and the antibacterial function observed by UBM is potentially through both the anti-biofilm activity and enhanced host immunity following UBM treatment. Taken together, our results support further investigation of UBM as an alternative treatment to attenuate bacterial-induced respiratory infection.

Regeneration of lingual musculature in rats using myoblasts over porcine bladder acellular matrix.

OBJECTIVES: To use tissue engineering muscle repair (TEMR) for regenerating the lingual musculature of hemiglossectomized rats using neonatal myoblasts (NM) on porcine acellular urinary bladder matrix (AUBM). MATERIAL AND METHODS: The study used 80 male rats. A volumetric muscle loss (VML) injury was created on the left side of the tongue. The rats were randomized into four groups: Group 1 (AUBM + myoblasts); Group 2 (AUBM); Group 3 (myoblasts); and Group 4 (control). NM were obtained from neonatal rats. The animals were weighed on day 0 and just before euthanasia. Five rats in each group were euthanized at days 2, 14, 28, and 42; the tongues were prepared for morphometric analysis, postoperative left hemitongue weight, and immunohistochemical analysis (desmin, CD-31, and anti-neurofilament). RESULTS: The weight gain from greatest to least was as follows: AUBM + myoblasts > myoblasts > AUBM > control. The tongue dorsum occupied by VML, and difference in mg between control side and intervened side from least to great was as follows: AUBM + myoblasts < myoblasts < AUBM < control. The order from highest to lowest antibody positivity was as follows: AUBM + myoblasts > myoblasts > AUBM > control. CONCLUSION: The use of porcine AUBM and NM for the regeneration of lingual musculature was found to be an effective TEMR treatment for repairing tongue VML injury.

[Influence of porcine urinary bladder matrix and porcine acellular dermal matrix on wound healing of full-thickness skin defect in diabetic mice].

Objective: To compare the difference of pro-healing effect of porcine urinary bladder matrix (UBM) and porcine acellular dermal matrix (ADM) on full-thickness skin defect wounds in diabetic mice. Methods: Thirty-six type 2 diabetic BKS db/db mice aged 10 weeks were divided into UBM group and ADM group according to the random number table, with 18 mice in each group and preoperative molarity of non-fasting blood glucose higher than 16.6 mmol/L. A circular full-thickness skin defect wound with 6 mm in diameter was made on the back of each mouse, and porcine UBM and porcine ADM scaffolds were implanted into the wounds of both groups correspondingly. Immediately after operation and on post operation day (POD) 7, 14, and 28, wounds were observed generally. On POD 7, 14, and 28, 6 mice of each group were collected respectively to calculate the rate of wound epithelialization, and then the corresponding mice were sacrificed after calculation, and the wound tissue was harvested to make slices. Six slices of the mice in the 2 groups on POD 7 and 14 were respectively collected to stain with haematoxylin-eosin (HE), and 6 slices on POD 7 and 28 had Masson's staining, which were used to observe histopathological changes and scaffold degradation. On POD 7 and 14, 24 slices of each mouse in the 2 groups were collected respectively to detect alpha smooth muscle actin (α-SMA) and CD31 positive expression denoting the growth of myofibroblasts and neovessels respectively and observe the distribution and activation of macrophages with immunohistochemical staining. The wound tissue of mice in the 2 groups on POD 7 and 14 was harvested to detect mRNA expressions of fibroblast growth factor 2 (FGF-2), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and transforming growth factor ß(1) (TGF-ß(1)) by real-time fluorescence quantitative reverse transcription polymerase chain reaction. The sample number of above-mentioned indexes in each group at each time point was 6. Data were statistically analyzed with analysis of variance for factorial design, t test, and Bonferroni correction. Results: (1) General observation showed that integration of UBM scaffold into the wounds of mice in UBM group on most time points was superior, and integration of ADM scaffold into the wounds of mice in ADM group on most time points was inferior. On POD 28, epidermis still did not form in some region of scaffold surface of wounds of mice in ADM group, while wounds of mice in UBM group were completely epithelialized. On POD 7, 14, and 28, wound epithelialization rates of mice in UBM group were respectively (22.4±6.4)%, (68.6±12.4)%, and 100.0%, all significantly higher than (4.5±2.2)%, (23.6±4.6)%, and (64.2±13.2)% in ADM group (t=7.427, 9.665, 7.655, P<0.01). (2) HE staining and Masson's staining showed that a large number of cells appeared in wound scaffold of mice in UBM group on POD 7; cells distributed in the whole region of UBM scaffold on POD 14; dermal tissue with structure similar to normal skin formed in the wounds and the fibrous morph of UBM scaffolds disappeared on POD 28. Only a small number of cells appeared in inside of wound scaffolds of mice in ADM group on POD 7; on POD 14, cells were sparsely distributed in ADM scaffolds; on POD 28, the morph of originally robust collagen fiber of ADM scaffolds was still clear and visible. (3) On POD 7, a large number of accumulated myofibroblasts and neovessels appeared in the lower layers of scaffolds of wounds of mice in UBM group; on POD 14, evenly distributed myofibroblasts and neovessels appeared in the upper layers of UBM scaffolds, and most vessels were perfused. On POD 7 and 14, myofibroblasts were sparsely distributed in scaffolds of wounds of mice in ADM group with no or a few neovascular structures perfused unobviously. On POD 7 and 14, α-SMA positive expressions in scaffolds of wounds of mice in UBM group were significantly higher than those in ADM group (t=25.340, 6.651, P<0.01); CD31 positive expressions were also significantly higher than those in ADM group (t=34.225, 10.581, P<0.01). (4) On POD 7, a large number of macrophages appeared in the lower layers of scaffolds of wounds of mice in UBM group; on POD 14, macrophages infiltrated into the internal region of UBM scaffolds, and M2 polarization occured without M1 polarization. On POD 7, a small number of macrophages appeared in the bottom of scaffolds of wounds of mice in ADM group; on POD 14, macrophages were few in internal region of ADM scaffold, and neither M2 polarization nor M1 polarization occurred. (5) On POD 7 and 14, mRNA expressions of FGF-2, VEGF, PDGF, and TGF-ß(1) in the wound tissue of mice in UBM group were all significantly higher than those in ADM group (t=7.007, 14.770, 10.670, 8.939; 7.174, 7.770, 4.374, 4.501, P<0.01). Conclusions: Porcine UBM scaffold is better than porcine ADM in facilitating wound repair and dermis reconstruction of full-thickness skin defects in diabetic mice through the induction of myofibroblasts and macrophages immigration, the promotion of neovascularization and expression of pro-healing growth factors.

Characterization of Porcine Urinary Bladder Matrix Hydrogels from Sodium Dodecyl Sulfate Decellularization Method.

Urinary bladder matrix (UBM) is one of the most studied extracellular matrixes (ECM) in the tissue engineering field. Although almost all of the UBM hydrogels were prepared by using peracetic acid (PAA), recent studies indicated that PAA was not a trustworthy way to decellularize UBM. A stronger detergent, such as sodium dodecyl sulfate (SDS), may help tackle this issue; however, its effects on the hydrogels' characteristics remain unknown. Therefore, the objective of this study was to develop a more reliable protocol to decellularize UBM, using SDS, and to compare the characteristics of hydrogels obtained from this method to the widely employed technique, using PAA. The results indicated that SDS was superior to PAA in decellularization efficacy. Different decellularization methods led to dissimilar gelation kinetics; however, the methods did not affect other hydrogel characteristics in terms of biochemical composition, surface morphology and rheological properties. The SDS-treated hydrogels possessed excellent cytocompatibility in vitro. These results showed that the SDS decellularization method could offer a more stable and safer way to obtain acellular UBM, due to reducing immunogenicity. The hydrogels prepared from this technique had comparable characteristics as those from PAA and could be a potential candidate as a scaffold for tissue remodeling.

Urinary Bladder Matrix Scaffolds Promote Pericardium Repair in a Porcine Model.

Pericardium closure after cardiac surgery is recommended to prevent postoperative adhesions to the sternum. Synthetic materials have been used as substitutes, with limited results because of impaired remodeling and fibrotic tissue formation. Urinary bladder matrix (UBM) scaffolds promote constructive remodeling that more closely resemble the native tissue. The aim of the study is to evaluate the host response to UBM scaffolds in a porcine model of partial pericardial resection. Twelve Landrace pigs were subjected to a median sternotomy. A 5 × 7 cm pericardial defect was created and then closed with a 5 × 7 cm multilayer UBM patch (UBM group) or left as an open defect (control group). Animals were survived for 8 wk. End points included gross morphology, biomechanical testing, histology with semiquantitative score, and cardiac function. The UBM group showed mild adhesions, whereas the control group showed fibrosis at the repair site, with robust adhesions and injury to the coronary bed. Load at failure (gr) and stiffness (gr/mm) were lower in the UBM group compared with the native pericardium (199.9 ± 59.2 versus 405.3 ± 99.89 g, P = 0.0536 and 44.23 ± 15.01 versus 146.5 ± 24.38 g/mm, P = 0.0025, respectively). In the UBM group, the histology resembled native pericardial tissue, with neovascularization, neofibroblasts, and little inflammatory signs. In contrast, control group showed fibrotic tissue with mononuclear infiltrates and a lack of organized collagen fibers validated with a histologic score. Both groups had normal ultrasonography results without cardiac motility disorders. In this setting, UBM scaffolds showed appropriate features for pericardial repair, restoring tissue properties that could help reduce postsurgical adhesions and prevent its associated complications.

Urinary bladder matrix does not improve tenogenesis in an in vitro equine model.

Extracellular matrix (ECM) is responsible for tendon strength and elasticity. Healed tendon ECM lacks structural integrity, leading to reinjury. Porcine urinary bladder matrix (UBM) provides a scaffold and source of bioactive proteins to improve tissue healing, but has received limited attention for treating tendon injuries. The objective of this study was to evaluate the ability of UBM to induce matrix organization and tenogenesis using a novel in vitro model. We hypothesized that addition of UBM to tendon ECM hydrogels would improve matrix organization and cell differentiation. Hydrogels seeded with bone marrow cells (n = 6 adult horses) were cast using rat tail tendon ECM ± UBM, fixed under static tension and harvested at 7 and 21 days for construct contraction, cell viability, histology, biochemistry, and gene expression. By day 7, UBM constructs contracted significantly from baseline, whereas control constructs did not. Both control and UBM constructs contracted significantly by day 21. In both groups, cells remained viable over time and changed from round and randomly oriented to elongated along lines of tension with visible compaction of the ECM. There were no differences over time or between treatments for nuclear aspect ratio, DNA, or glycosaminoglycan content. Decorin, MMP-13, and Scleraxis expression increased significantly over time, but not in response to UBM treatment. Mohawk expression was constant over time. COMP expression decreased over time in both groups. Using a novel ECM hydrogel model, substantial matrix organization and cell differentiation occurred; however, addition of UBM failed to induce greater matrix organization than tendon ECM alone. This article is protected by copyright. All rights reserved.

Urinary Bladder Matrix Does Not Improve Tenogenesis in an In Vitro Equine Model.

Extracellular matrix (ECM) is responsible for tendon strength and elasticity. Healed tendon ECM lacks structural integrity, leading to reinjury. Porcine urinary bladder matrix (UBM) provides a scaffold and source of bioactive proteins to improve tissue healing, but has received limited attention for treating tendon injuries. The objective of this study was to evaluate the ability of UBM to induce matrix organization and tenogenesis using a novel in vitro model. We hypothesized that addition of UBM to tendon ECM hydrogels would improve matrix organization and cell differentiation. Hydrogels seeded with bone marrow cells (n = 6 adult horses) were cast using rat tail tendon ECM ± UBM, fixed under static tension and harvested at 7 and 21 days for construct contraction, cell viability, histology, biochemistry, and gene expression. By day 7, UBM constructs contracted significantly from baseline, whereas control constructs did not. Both control and UBM constructs contracted significantly by day 21. In both groups, cells remained viable over time and changed from round and randomly oriented to elongated along lines of tension with visible compaction of the ECM. There were no differences over time or between treatments for nuclear aspect ratio, DNA, or glycosaminoglycan content. Decorin, matrix metalloproteinase 13, and scleraxis expression increased significantly over time, but not in response to UBM treatment. Mohawk expression was constant over time. Cartilage oligomeric matrix protein expression decreased over time in both groups. Using a novel ECM hydrogel model, substantial matrix organization and cell differentiation occurred; however, the addition of UBM failed to induce greater matrix organization than tendon ECM alone. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1848-1859, 2019.