Urinary Bladder Submucosa Research Articles

Impact of Using Processed Urinary Bladder Submucosa and Hydrogel Fabricated from Tendon on Skin Healing Process in Rabbits.

This study was intended to evaluate the healing of skin injury by using decellularized urinary bladder submucosa scaffolds and tendon-derived hydrogel. Thirty-six adult local breeds of both sex rabbits, with an average weight of 2.0-2.5 kg, were divided randomly into three groups (12 animals for each group). All groups were subjected to an induced injury (2 cm) in diameter at the right side of the abdominal skin, the rabbits of the 1st group (A) were sutured without the application of any substance as a control group, the rabbits of the 2nd group (B) were sutured and treated with the application of decellularized urinary bladder submucosa scaffolds, and in the 3rd group (C), they were sutured and treated with the application of tendon-derived hydrogel. Postoperative care following had been done for all groups throughout the study period. Specimens from the injured skin were taken for the histopathological study on the postinjury day, 8th, 14th, 21st, and 24th. The study showed a clear effect of materials used in the treatment of wounds through a clear progression in the healing stages with a noticed superiority of the submucosa scaffold group.

Construction and Evaluation of a Bio-Engineered Pump to Enable Subpulmonary Support of the Fontan Circulation: A Proof-of-Concept Study.

Our objective was to create a bio-engineered pump (BEP) for subpulmonary Fontan circulation support capable of luminal endothelialization and producing a 2-6 mmHg pressure gradient across the device without flow obstruction. To accomplish this, porcine urinary bladder submucosa was decellularized to produce a urinary bladder matrix (UBM) which produced acellular sheets of UBM. The UBM was cultured with human umbilical vein endothelial cells producing a nearly confluent monolayer of cells with the maintenance of typical histologic features demonstrating UBM to be a suitable substrate for endothelial cells. A lamination process created bilayer UBM sheets which were formed into biologic reservoirs. BEPs were constructed by securing the biologic reservoir between inlet and outlet valves and compressed with a polyurethane balloon. BEP function was evaluated in a simple flow loop representative of a modified subpulmonary Fontan circulation. A BEP with a 92-mL biologic reservoir operating at 60 cycles per minute produced pulsatile downstream flows without flow obstruction and generated a favorable pressure gradient across the device, maintaining upstream pressure of 6 mm Hg and producing downstream pressure of 13 mm Hg. The BEP represents potential long-term assistance for the Fontan circulation to relieve venous hypertension, provide pulsatile pulmonary blood flow and maintain cardiac preload.

Efficacy of Acellular-Lyophilized Human Umbilical Cord Powder Seeded with Human Umbilical Cord Mesenchymal Stem Cells in Peripheral Nerve Regeneration in Dogs Models

Treatment of injuries to peripheral nerves after a segmental defect is one of the most challenging surgicalproblems. Therapies for peripheral nerves injury are largely ineffective. Therefore, the current study wasconducted to investigate effects either acellular human umbilical cord tissue powder on repair 1 cm criticalsize defect radial nerve guided by bovine urinary bladder matrix conduit alone or seeded with mesenchymalstem cells derived from human umbilical cord. For this purpose, sixteen healthy mongrel dogs were used.They were randomly divided into two equal groups (n=8), before proceeding with the surgical procedures,the dogs were generally anesthetized and aseptic conditions were established. Then, the surgery was carriedout with the aid of magnifying lens. All dogs subjected to radial nerve neurotmesis from the right limb. Inthe scaffold group, a 1cm of radial nerve was transected and resulted gap bridged with a portion of 14mmacellular bovine urinary bladder submucosa conduit which was then filled with 0.05mg acellular humanumbilical cord powder and then sutured to the two stumps using 6-0 nylon epineural by simple interruptedpattern. In combination group, the gap was bridged with acellular bovine urinary bladder submucosa conduitwhich was filled with 0.05mg acellular human umbilical cord powder then seeded with 50 µl (5x106)mesenchymal stem cells derived from human umbilical cord, then fixed onto two stumps using 6-0 nylonepineural by simple interrupted pattern. Each group was further divided into two equal subgroups (n=4)categorized according to the post operation periods, that were 8 and 16th weeks for neurohistopathologicalexaminations. The histopathological examination of regenerated nerve sections (two samples of 5 mm lengtheach) were collected from the middle (coaptation site) and distal segments were used to determine the degreeof the radial nerve regeneration. The histopathological findings relative convergence between the scaffoldand combination groups in their components such as the increased number of Schwann cells proliferation,parallel arrangement of nerve fibers and remarkable angiogenesis on 16th weeks. In conclusion; this studyshowed that the decellularized both scaffolds alone or seeded with mesenchymal stem cells derived fromhuman umbilical cord could support the radial nerve regeneration and allow the reinnervation of the targetorgan.

Malakoplakia of the Bladder in a 4-Month-Old Puppy.

A 4 mo old female Staffordshire bull terrier puppy was presented with chronic Escherichia coli cystitis. Ultrasound and cystoscopic examination revealed innumerable, intraluminal, finger-like proliferations arising from the dorsal urinary bladder (UB) wall. Histological examination of mucosal biopsies obtained by cystoscopy was suggestive of granulomatous cystitis. The proliferative lesions were removed surgically and submitted for histological examination. The UB submucosa was heavily infiltrated by macrophages with periodic acid-Schiff-positive cytoplasm exhibiting rare Michaelis-Gutmann bodies, leading to the diagnosis of malakoplakia. The puppy was prescribed with sulfamethoxazole-trimethoprim. The urinary signs disappeared despite the persistent UB wall thickening revealed by abdominal ultrasound. Urine culture performed during the ninth week of treatment showed a persistent infection by E coli resistant to sulfamethoxazole-trimethoprim. The dog was switched to doxycycline but was then lost to follow-up. Malakoplakia is a chronic granulomatous inflammation well documented in humans. Its pathophysiology is not fully understood, but bacterial infection, immunodepression, and a defective lysosomal function may lead to the intracytoplasmic accumulation of partially degraded bacteria that can subsequently mineralize to form the Michaelis-Gutmann bodies. Malakoplakia should be suspected when UB mass lesions are identified in a young dog with bacterial cystitis.

Effect of Acellular Bovine Pericardium and Urinary Bladder Submucosa Matrixes in Reconstruction of Ventro-Lateral Hernias in Bucks; Molecular Evaluation

The present study aimed to estimate the efficiency of both a cellular bovine pericardium and bovine urinary bladder matrix sheets in the reconstruction of large ventro-lateral hernias in Iraqi bucks by using of molecular evaluation depending on real time-polymerase chain reaction technique to investigate the level of basic-fibroblast growth factor and vascular endothelial growth factor genes during the healing process and reconstruction of the abdominal defects. Under sedation and local anesthesia, (6cm X 8cm size) of ventro-lateral hernias were induced in 24 of Iraqi bucks. The animals were divided randomly into two main equal groups. In bovine pericardium-treatment group, the hernias were treated with onlay implantation of bovine pericardium. While, the hernias in UBM-treatment group were treated with onlay implantation of urinary bladder matrix, 30 days post-inducing of hernias. The molecular evaluation along the period of following-up recorded a significant up-regulation of the level of basic-fibroblast growth factor gene specific for presence of fibroblasts, myofibroblasts and collagen deposition in urinary bladder matrix -treatment group in comparison to bovine pericardium -treatment group with significant difference even at the end of the study. While, a significant up regulation of the levels of angiogenesis classic gene vascular endothelial growth factor were recorded in the bucks of bovine pericardium -treatment group compared to urinary bladder matrix -treatment group. In conclusion; molecular detection of the level of growth factors in target tissue can be used as an important criterion.

Role of acellular bovine urinary bladder submucosa on skin wound healing in Iraqi goats

This study is designed to assess the effectiveness of bovine urinary bladder submucosa on healing of cutaneous wound in Iraqi goats. A 32 (2X2) cm of full-thickness cutaneous wounds were induced in eight goats, two on each side of the lateral thoracic region. The wounds were divided into two equal groups (16 wounds/ group); treatment group included the wounds on the right side which were treated by covering the wound beds with strips of acellular sterilized bovine urinary bladder matrix. While, the wounds on the left side were left without any treatment (control group). The results were evaluated clinically (along) and histopathologically on 7, 14, 21, and 35 days post-inducing of wounds. The clinical evaluation of treated wounds showed that the wound healing process contraction%, re-epithelization % and total wound healing % were P<0.05 significantly than that of control wounds at 35 days of the study. The histopathological results confirmed that urinary bladder matrix treated wounds have enhanced cellularity, increased vasculature, thick and large granulation tissue suggesting enhanced cutaneous healing, than those in untreated wounds. Depending on the clinical and histopathological findings, this study concluded that a cellular bovine urinary bladder matrix play an important role in stimulation of cutaneous wound healing of goats without signs of immuno-rejection.

Retrospective evaluation of corneal reconstruction using ACell Vet(™) alone in dogs and cats: 82 cases.

To retrospectively evaluate the complications, graft clarity, and outcomes associated with the use of commercially available porcine urinary bladder submucosa (ACell Vet(™) ) alone for corneal reconstruction in dogs and cats. Dogs or cats receiving an ACell Vet(™) graft for corneal reconstruction due to severe ulcerative keratitis or after a keratectomy to remove a corneal sequestrum were included. All received a single layer of ACell Vet(™) , bandage contact lens, and temporary tarsorrhaphy. Bandage contact lens and temporary tarsorrhaphy were removed after graft vascularization or epithelialization. Topical steroids, cyclosporine, tacrolimus were started after epithelialization. Based on their last examination, outcomes were categorized into five groups based on the presence of corneal vessels, appearance of the scar, and the ability to visualize the posterior and/or the anterior segment through the grafted area. There were 82 eyes included in the study, with 68 eyes with sufficient follow-up time for final assessment. Scarring was minimal in 47 eyes, moderate but not enough to obscure visualization of the posterior segment in 12, and severe in nine. There were five eyes that developed phthisis bulbi, glaucoma or were enucleated and nine that were lost to follow up. Graft dehiscence occurred in 19 eyes. Twelve healed without additional surgical intervention while three required a second graft, two became phthisical, and two were enucleated. Corneal reconstruction with ACell Vet(™) alone is a viable alternative and results in minimal scarring and complications in cats. In dogs, scarring is more pronounced than in cats and graft dehiscence rate is higher compared to conventional techniques.

Oxygen diffusivity of biologic and synthetic scaffold materials for tissue engineering

Scaffolds for tissue engineering and regenerative medicine applications are commonly manufactured from synthetic materials, intact or isolated components of extracellular matrix (ECM), or a combination of such materials. After surgical implantation, the metabolic requirements of cells that populate the scaffold depend upon adequate gas and nutrient exchange with the surrounding microenvironment. The present study measured the oxygen transfer through three biologic scaffold materials composed of ECM including small intestinal submucosa (SIS), urinary bladder submucosa (UBS), and urinary bladder matrix (UBM), and one synthetic biomaterial, Dacron. The oxygen diffusivity was calculated from Fick's first law of diffusion. Each material permitted measurable oxygen diffusion. The diffusivity of SIS was found to be dependent on the direction of oxygen transfer; the oxygen transfer in the abluminal-to-luminal direction was significantly greater than the luminal-to-abluminal direction. The oxygen diffusivity of UBM and UBS were similar despite the presence of an intact basement membrane on the luminal surface of UBM. Dacron showed oxygen diffusivity values seven times greater than the ECM biomaterials. The current study showed that each material has unique oxygen diffusivity values, and these values may be dependent on the scaffold's ultrastructure.

Collagen fiber alignment and biaxial mechanical behavior of porcine urinary bladder derived extracellular matrix

The collagen fiber alignment and biomechanical behavior of naturally occurring extracellular matrix (ECM) scaffolds are important considerations for the design of medical devices from these materials. Both should be considered in order to produce a device to meet tissue specific mechanical requirements (e.g., tendon vs. urinary bladder), and could ultimately affect the remodeling response in vivo. The present study evaluated the collagen fiber alignment and biaxial mechanical behavior of ECM scaffold material harvested from porcine urinary bladder tunica mucosa and basement membrane (together referred to as urinary bladder matrix (UBM)) and ECM harvested from urinary bladder submucosa (UBS). Since the preparation of UBM allows for control of the direction of delamination, the effect of the delamination method on the mechanical behavior of UBM was determined by delaminating the submucosa and other abluminal layers by scraping along the longitudinal axis of the bladder (apex to neck) (UBML) or along the circumferential direction (UBMC). The processing of UBS does not allow for similar directional control. UBML and UBS had similar collagen fiber distributions, with a preferred collagen fiber alignment along the longitudinal direction. UBMC showed a more homogenous collagen fiber orientation. All samples showed a stiffer mechanical behavior in the longitudinal direction. Despite similar collagen fiber distributions, UBML and UBS showed quite different mechanical behavior for the applied loading patterns with UBS showing a much more pronounced toe region. The mechanical behavior for UBMC in both directions was similar to the mechanical behavior of UBML. There are distinct differences in the mechanical behavior of different layers of ECM from the porcine urinary bladder, and the processing methods can substantially alter the mechanical behavior observed.

Morphologic study of three collagen materials for body wall repair

Background The search for ideal prostheses for body wall repair continues. Synthetic materials such as polypropylene mesh (PPM) are associated with healing complications. A porcine-derived collagen-based material (CBM), small intestinal submucosa (SIS), has been studied for body wall repair. Renal capsule matrix (RCM) and urinary bladder submucosa (UBS) are CBMs not previously evaluated in this application. This is the first implant study using RCM. Materials and methods Full-thickness muscle/fascia ventral abdominal wall defects were repaired with SIS, RCM, UBS, and PPM in rats with omentum and omentectomy. A random complete block design was used to allot implant type to each of 96 rats. Healing was evaluated at 4 and 8 weeks. Adhesion tenacity and surface area were scored. Implant site dimensions were measured at implantation and necropsy. Inflammation, vascularization, and fibrosis were histopathologically scored. Data were compared by analysis of variance ( P < 0.05). Results PPM produced a granulomatous foreign body response in contrast to the organized healing of CBM implants. CBM mean scores were lower than PPM scores for adhesion tenacity, surface area, and inflammation at each follow-up time for rats with omentums ( P < 0.02). The CBMs had less tenacity and inflammation than PPM at each follow-up time in omentectomy groups ( P < 0.008). Wound contraction was greater for PPM ( P < 0.0001) for all rats. Conclusions RCM and UBS were similar to SIS invoking reduced inflammation, adhesion, and contraction compared to PPM. The fibrotic response to PPM was unique and more intense compared to CBMs. These CBM implants appear morphologically acceptable and warrant continued investigation.

Biaxial strength of multilaminated extracellular matrix scaffolds

Xenogeneic extracellular matrix (ECM) can be harvested and configured to function as a bioscaffold for tissue and organ reconstruction. The mechanical properties of the ECM vary depending upon the tissue from which it is harvested. Likewise, the manufacturing steps required to develop ECMs into medical grade devices will affect the surface morphology and the mechanical properties of the bioscaffold; important properties for constructive tissue remodeling. The present study compared the ball-burst strength of five different ECM scaffolds before and after treatment with peracetic acid (PAA): porcine small intestinal submucosa (SIS), porcine urinary bladder submucosa (UBS), porcine urinary bladder matrix (UBM), a composite of UBS+UBM, and canine stomach submucosa (SS). This study also compared the mechanical properties of 2- and 4-layer ECM scaffolds. Results showed 2-layer SS devices had the highest ball-burst value of all 2-layer ECM devices. Moreover, all 4-layer ECM devices had similar ball-burst strength except for 4-layer UBM devices which was the weakest. PAA-treatment decreased the ball-burst strength of SS and increased the ball-burst strength of UBS 2-layer devices. This study showed the material properties of the ECM scaffolds could be engineered to mimic those of native soft tissues (i.e. vascular, musculotendinous, etc) by varying the number of layers and modifying the disinfection/sterilization treatments used for manufacturing.

Antimicrobial activity associated with extracellular matrices.

Materials derived from extracellular matrices (ECMs) are being evaluated as scaffolds for surgical reconstruction of damaged or missing tissues. It is important to understand the susceptibility of these biological materials to bacterial infections. ECMs derived from porcine small intestinal submucosa (SIS) and urinary bladder submucosa (UBS) were found to possess antimicrobial activity. ECM extracts, obtained by digesting these acellular matrices in acetic acid, demonstrated antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Antimicrobial activity was determined using a minimal inhibitory concentration assay. Bacteriostatic activity was detected at protein concentrations of ECM extracts equivalent to 0.77-1.60 mg/mL. ECM extracts were found to inhibit bacterial growth for up to at least 13 h. The resulting extracts consisted of water-soluble peptides and proteins with molecular weights ranging from <4 to >100 kDa and lower molecular weight compounds, as determined by size exclusion liquid chromatography.

Resorbable bioscaffold for esophageal repair in a dog model

Purpose: Porcine-derived, xenogeneic extracellular matrix (ECM) derived from either the small intestinal submucosa (SIS) or urinary bladder submucosa (UBS) was used as a tissue scaffold for esophageal repair in a dog model. Methods: Patch defects measuring approximately 5 cm in length and encompassing 40% to 50% of the circumference of the esophagus or complete circumferential segmental defects measuring 5 cm in length were created by surgical resection in healthy adult female dogs. The defects were repaired with ECM scaffolds derived from either SIS or UBS. The animals were kept alive for periods ranging from 4 days to 15 months. Results: The xenogeneic scaffolds used for repair of the patch defects were resorbed completely within 30 to 60 days and showed replacement by skeletal muscle, which was oriented appropriately and contiguous with adjacent normal esophageal skeletal muscle, organized collagenous connective tissue, and a complete and intact squamous epithelium. No signs of clinical esophageal dysfunction were seen in any of the animals with the patch defect repair. The xenogeneic scaffolds configured into tubes for repair of the segmental defects all showed stricture within 45 days of surgery. Conclusion: These ECMs show promise as a treatment option for esophageal repair, but stricture remains problematic for complete tube grafts. J Pediatr Surg 35:1097-1103. Copyright © 2000 by W.B. Saunders Company.

Evaluation of autologous fat implantation in the rat urinary bladder submucosa

Objectives. Autologous fat has been used as a bulking implant material for stress urinary incontinence. There is considerable controversy as to the ultimate fate of the grafted fat. This study was conducted to determine the fate of autogenous fat implanted into the bladder of rats. Methods. Two groups of adult female rats were studied. In the test animals (group 1, n = 20), mesenteric adipose tissue (1 mL) was harvested and homogenized with an equal weight of sterile saline. Using a 25-gauge needle, 0.5 g of saline-fat mixture was injected into the dorsal bladder neck submucosa. Control animals (group 2, n = 12) were injected with sterile saline only. A subset of animals from each group were killed after 7, 35, 105, and 150 days, and the bladder and urethra were fixed. The fixed tissue was examined microscopically and photographed at each follow-up period. Results. Seven days after injection of fat, there was a pronounced acute inflammatory reaction with numerous polymorphonuclear leukocytes and macrophages at the site of fat injection. There was minimal inflammatory reaction at the site of saline injection. By day 35, most of the fat had been eliminated by these phagocytes because of severe acute and chronic inflammation. By day 105, the submucosa tissue of the experimental rats had returned to normal visually and to a flat surface, lacking the appearance of a sizable “bulge” as shown at days 0 and 7. Histopathologic findings were also similar to the control rats. Inflammatory cells were no longer present by day 105. Conclusions. The implantation of homogenized, autologous fat in the rat urinary bladder submucosa causes acute and chronic inflammation and fat necrosis. The severe phagocytosis at the implant sites eliminates the vast majority of the devitalized implanted fat during the first month.