Porcine Small Intestinal Submucosa Research Articles

Use of Decellularised Porcine Intestinal Submucosa Extracellular Matrix in Airway Reconstruction to Enable Lung-sparing Oncological Surgery

Background: Reconstruction of the airways following tracheal or lung-sparing oncological surgery is challenging. A novel approach is the use of bioscaffolds, which allow regeneration of respiratory epithelium and eliminate the need for immunosuppression. Initial experiences with decellularised porcine small intestine submucosa extracellular matrix (CorMatrix) as a scaffold for vascular and cardiac surgery have been encouraging. Its properties are potentially suitable for airway reconstruction.

Successful Treatment of Spectacle Avulsion in a Brazilian Rainbow Boa (Epicrates cenchria cenchria) by Using a Porcine Small Intestinal Submucosal Graft

Abstract A 5-yr-old, male Brazilian rainbow boa (Epicrates cenchria cenchria) presented with a partial spectacle avulsion that progressed to full spectacle avulsion following ecdysis. A porcine small intestinal submucosal graft was sutured over the cornea to protect the globe and allow the spectacle to regenerate. Treatment included topical antibiotic and lubricant ophthalmic medications. The porcine small intestinal submucosal graft was shed during ecdysis 30 days after placement, revealing peripheral regeneration of the spectacle with a 1- to 2-mm crust covering a presumed central defect. At the next ecdysis 39 days later, the spectacle had completely regenerated. Application of a porcine small intestinal submucosal graft in combination with topical antibiotic and lubricant ophthalmic medications for treatment of complete spectacle avulsion was successful in allowing spectacle regeneration and was well tolerated by the rainbow boa in this case.

P3.16-052 Use of Decellularised Porcine Intestinal Submucosa Extracellular Matrix in Airway Reconstruction to Enable Lung-Sparing Oncological Surgery

Reconstruction of the airways following tracheal resection, tracheo-oesophageal complications and lung-sparing oncological surgery is challenging. Airway reconstruction materials ideally must possess balanced properties of rigidity, flexibility and have an intact surface of epithelium to maintain a functional airway. A novel approach is the use of bio-scaffolds which allow regeneration of respiratory epithelium and eliminate the need for immunosuppressive treatment. Initial experiences with decellularised porcine small intestine submucosa extracellular matrix (CorMatrix®) as a scaffold for vascular, cardiac and pericardial tissue repair and reconstruction has been encouraging. The properties of extracellular matrix are potentially suitable for airway reconstruction. We initially used the bio-scaffold for repairing tracheal defects and tracheo-oesophageal fistulae (n=6). We then extended its use to reconstruct distal airways to facilitate lung-sparing oncologic resections of intermediate grade lung tumours (n=3). These patients would otherwise have required pneumonectomy (Case 1 and 2) or bi-lobectomy in a patient with borderline lung function (Case 3). We describe our experience using extracellular matrix for airway reconstruction in lung-sparing oncological surgery. Three patients underwent complex sleeve resections with varying degrees of bronchial airway reconstruction using extracellular matrix. The lung tumours were: (1) muco-epidermoid tumour of the left upper lobe and left main bronchus; (2) typical carcinoid of the right main bronchus; (3) typical carcinoid of the intermediate bronchus and right middle lobe. All patients underwent frozen section pathology examination at the time of surgery and formal histology confirmed pT1N0 and R0 resection status. There were no perioperative complications. All patients underwent bronchoscopy prior to discharge and serial bronchoscopies were carried out 6 weeks, 3 months and at >1 year. All patients had complete integration of the scaffold by epithelialisation and the patch was not evident at 3 months. All segmental bronchi were widely patent. At 18 months there was no tumour recurrence. The use of decellularised porcine intestinal submucosa extracellular matrix (CorMatrix®) as a bio-scaffold is safe and shows remarkable epithelialisation and integrity. It is an option for airway reconstruction to facilitate lung-sparing surgery without compromising oncologic margins.

Transplantation of Isl1+ cardiac progenitor cells in small intestinal submucosa improves infarcted heart function

BackgroundApplication of cardiac stem cells combined with biomaterial scaffold is a promising therapeutic strategy for heart repair after myocardial infarction. However, the optimal cell types and biomaterials remain elusive.MethodsIn this study, we seeded Isl1+ embryonic cardiac progenitor cells (CPCs) into decellularized porcine small intestinal submucosa extracellular matrix (SIS-ECM) to assess the therapeutic potential of Isl1+ CPCs and the biocompatibility of SIS-ECM with these cells.ResultsWe observed that SIS-ECM supported the viability and attachment of Isl1+ CPCs. Importantly, Isl1+ CPCs differentiated into cardiomyocytes and endothelial cells 7 days after seeding into SIS-ECM. In addition, SIS-ECM with CPC-derived cardiomyocytes showed spontaneous contraction and responded to β-adrenergic stimulation. Next, patches of SIS-ECM seeded with CPCs for 7 days were transplanted onto the outer surface of infarcted myocardium in mice. Four weeks after transplantation, the patches were tightly attached to the surface of the host myocardium and remained viable. Transplantation of patches improved cardiac function, decreased the left ventricular myocardial scarring area, and reduced fibrosis and heart failure.ConclusionsTransplantation of Isl1+ CPCs seeded in SIS-ECM represents an effective approach for cell-based heart therapy.

Placental mesenchymal stromal cells seeded on clinical grade extracellular matrix improve ambulation in ovine myelomeningocele

PurposeThe purpose of this study was to investigate the effects of placental mesenchymal stromal cells (PMSCs) seeded on a clinical grade porcine small intestinal submucosa (SIS)-derived extracellular matrix (ECM) on hindlimb motor function in an ovine fetal repair model of myelomeningocele (MMC). MethodsMMC defects were surgically created in 21 fetuses at median gestational age 78 (range 76–83) days. Fetuses were randomly assigned to repair 25days later with ECM only or PMSC-ECM. Surviving fetuses were delivered at term. Motor function was evaluated using the Sheep Locomotor Rating (SLR) scale (0–15). Histologic analysis of the spinal cord (SC) was completed. ResultsFetal viability was 71%. 5 of 8 (63%) lambs repaired with PMSC-ECM ambulated independently versus only 1 of 6 (17%) repaired with ECM only (p=0.04, χ2 test). SLR scores and large neuron densities were higher in the PMSC-ECM group. The cross-sectional areas of the SC and the gray matter were equally preserved. ConclusionsFetal repair of MMC with PMSCs seeded on SIS-ECM improves hindlimb motor function in lambs. Using ECM helps to preserve the architecture of the SC, but adding PMSCs improves the lamb's ability to walk and increases large neuron density. Clinical studies are needed to show benefits in humans. Levels of evidence/type of studyBasic Science.

31 - A Comparative Study of Sexual and Functional Outcomes of Vaginoplasty Through Three Methods

Study Objective: To compare the sexual and functional outcomes in patients with Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) through Sheares vaginoplasty, vaginoplasty using acellular porcine small intestinal submucosa (SIS) graft and laparoscopic peritoneal vaginoplasty.

Use of a Rat Model to Study Ventral Abdominal Hernia Repair.

Ventral abdominal hernia is a relatively common clinical condition that sometimes requires herniorraphy (surgical repair). The repair of ventral abdominal hernia typically requires implantation of a material to serve as a mechanical bridge across the defect in the abdominal wall. Biomaterials, such as porcine small intestinal submucosa (SIS), also serve as a lattice for cell growth into the implant and can naturally incorporate into the host tissue. Development of such repair materials benefits from use of animal models in which experimental abdominal wall defects are easily created and are amenable to repair in a reproducible fashion. The method offered here describes surgical creation and repair of ventral abdominal hernia in a rat model. When SIS is used to repair an experimental ventral abdominal hernia in this model, it is rapidly incorporated into host tissue within 28 days of implantation. Histologically, incorporation of their implanted material into host tissue is characterized by a robust fibrovascular response. Future refinements and applications of the rat abdominal hernia model may likely involve diabetic and/or obese animals as a means to more closely mimic common co-morbidities of man.

The Study of Acellular Porcine Small Intestinal Submucosa Powders as a Hemostatic Agent to Stop the Bleeding in a Rat Spleen Partial Resection Model

The Study of Acellular Porcine Small Intestinal Submucosa Powders as a Hemostatic Agent to Stop the Bleeding in a Rat Spleen Partial Resection Model

Reduced urothelial regeneration in rat bladders augmented with permeable porcine small intestinal submucosa assessed by magnetic resonance imaging.

Augmentation enterocystoplasty remains the gold standard surgical bladder reconstruction procedure to increase the capacity and compliance of dysfunctional bladders. Since the use of the patient's intestine has severe risks of complications, alternative biodegradable matrices have been explored. Porcine small intestinal submucosa (SIS) has gained immense interests in bladder reconstruction due to its favorable properties. However, trials have shown inconsistent regeneration with SIS, attributed to the heterogeneity in microstructures and mechanical properties. We hypothesize that uneven SIS permeability to urine is a factor responsible for the inconsistency. We measured permeability to urine in situ using a contrast enhanced-magnetic resonance imaging (MRI), and evaluated urothelium regeneration using immunohistochemical staining of urothelial cell markers in SIS-augmented rat bladders. Results showed significant differences in permeability among SIS-augmented rat bladders. Commercial SIS scaffolds were then categorized into nonleaky and leaky groups based on MRI results. Hematoxylin and eosin staining showed higher numbers of inflammatory cells in leaky SIS on day 14 relative to nonleaky SIS. In addition, trichrome staining showed major changes in the distribution of collagen on day 28 between SIS-augmented bladder groups. Furthermore, expressions of urothelium-associated markers (cytokeratins AE1/AE3, claudin 4, and uroplakin III) were completed in bladders augmented with nonleaky SIS, whereas limited urothelial differentiation was noticed in leaky SIS-augmented bladders at post-augmentative day 14. These results show that scaffold permeability to urine may be responsible for variations in regenerative capacity of porcine SIS. Applications of MRI technique will be helpful to understand a relationship between biomaterial property and regenerative capacity. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1778-1787, 2018.

Use of porcine small intestinal submucosa for pediatric endoscopic tympanic membrane repair.

Tympanic membrane perforationsoccur frequently in children, and can result in hearing loss, otorrhea, pain, and cholesteatoma. Due to the narrower ear canal in children, a postauricular incision is often needed to access the tympanic membrane for surgical repair. Endoscopic approaches are increasingly being used for tympanic membrane repair, reducing the need for postauricular incisions. As the need for a postauricular incision decreases, the demand for non-autologous grafting material has increased. Acellular porcine small intestinal submucosa (SIS) has been described in the literature as an alternative to commonly used autologous grafts, and is well suited for use with transcanal endoscopic ear surgery as a minimally invasive approach. This paper describes techniques for use of SIS in endoscopic tympanic membrane repair in children.

Composite Scaffolds of Mineralized Natural Extracellular Matrix on True Bone Ceramic Induce Bone Regeneration Through Smad1/5/8 and ERK1/2 Pathways.

A stem cell-derived mineralized extracellular matrix (ECM) may be a good strategy to endow scaffolds with a bone microenvironment, thus inducing bone regeneration. However, it also faces some challenges, such as limited number of cells, additional wound for autologous cell isolation, and time consumption of cell expansion. In this study, we designed a novel tissue-derived ECM scaffold fabricated by depositing porcine small intestinal submucosa (SIS) ECM on true bone ceramic (TBC), which was followed by mineralization treatment (mSIS/TBC). In vitro, compared with pure TBC, mSIS/TBC promoted cell proliferation, cell viability, and osteoblastic differentiation of the newly seeded rat bone marrow mesenchymal stem cells (BMSCs), and upregulation of the messenger RNA (mRNA) level of osteogenesis-related genes. Western blot assay revealed that mSIS/TBC enhanced osteoblastic differentiation through activation of phosphorylated Smad1/5/8 and phosphorylated extracellular signal-regulated kinase (ERK), as an underlying mechanism. In vivo, in a rat cranial critical size defect model, mSIS/TBC scaffolds induced greater bone formation than pure TBC scaffolds. Meanwhile, a comparative study on the capacity of bone regeneration was also carried out between mSIS/TBC and BMSC-derived ECM deposited on TBC scaffold in vivo and in vitro. The results demonstrated that mSIS/TBC scaffolds acquired a comparable bone regeneration efficacy to that of BMSC-derived ECM deposited on TBC scaffolds. Collectively, our results demonstrated that mSIS/TBC enhanced bone regeneration by supporting cell proliferation and cell viability, and by activating Smad1/5/8 and ERK1/2 signal pathways of BMSC in vitro and in vivo; thus, mSIS/TBC is an excellent alternative to stem cell-derived ECM scaffold for bone regeneration.

Human umbilical cord blood–derived mesenchymal stromal cells and small intestinal submucosa hydrogel composite promotes combined radiation-wound healing of mice

Background aimsMesenchymal stromal cells (MSCs) are a promising agent for treating impaired wound healing, and their therapeutic potential may be enhanced by employing extracellular matrix scaffolds as cell culture scaffolds or transplant cell carriers. Here, we evaluated the effect of human umbilical cord blood–derived (hUCB)-MSCs and a porcine small intestinal submucosa (SIS)-derived extracellular matrix scaffold in a combined radiation-wound mouse model of impaired wound healing. MethodshUCB-MSCs and SIS hydrogel composite was applied to the excisional wound of whole-body irradiated mice. Assessment of wound closing and histological evaluation were performed in vivo. We also cultured hUCB-MSCs on SIS gel and examined the angiogenic effect of conditioned medium on irradiated human umbilical vein endothelial cells (HUVECs) in vitro. ResultshUCB-MSCs and SIS hydrogel composite treatment enhanced wound healing and angiogenesis in the wound site of mice. Conditioned medium from hUCB-MSCs cultured on SIS hydrogel promoted the chemotaxis of irradiated HUVECs more than their proliferation. The secretion of angiogenic growth factors hepatocyte growth factor, vascular endothelial growth factor-A and angiopoietin-1 from hUCB-MSCs was significantly increased by SIS hydrogel, with HGF being the predominant angiogenic factor of irradiated HUVECs. ConclusionsOur results suggest that the wound healing effect of hUCB-MSCs is enhanced by SIS hydrogel via a paracrine factor-mediated recruitment of vascular endothelial cells in a combined radiation-wound mouse model.

Matrix-Bound Nanovesicles Recapitulate Extracellular Matrix Effects on Macrophage Phenotype.

The early macrophage response to biomaterials has been shown to be a critical and predictive determinant of downstream outcomes. When properly prepared, bioscaffolds composed of mammalian extracellular matrix (ECM) have been shown to promote a transition in macrophage behavior from a proinflammatory to a regulatory/anti-inflammatory phenotype, which in turn has been associated with constructive and functional tissue repair. The mechanism by which ECM bioscaffolds promote this phenotypic transition, however, is poorly understood. The present study shows that matrix-bound nanovesicles (MBV), a component of ECM bioscaffolds, are capable of recapitulating the macrophage activation effects of the ECM bioscaffold from which they are derived. MBV isolated from two different source tissues, porcine urinary bladder and small intestinal submucosa, were found to be enriched in miRNA125b-5p, 143-3p, and 145-5p. Inhibition of these miRNAs within macrophages was associated with a gene and protein expression profile more consistent with a proinflammatory rather than an anti-inflammatory/regulatory phenotype. MBV and their associated miRNA cargo appear to play a significant role in mediating the effects of ECM bioscaffolds on macrophage phenotype.

In vivo investigation of tissue-engineered periosteum for the repair of allogeneic critical size bone defects in rabbits.

The aim of the study was to evaluate the efficacy of tissue-engineered periosteum (TEP) in repairing allogenic bone defects in the long term. TEP was biofabricated with osteoinduced rabbit bone marrow mesenchymal stem cells and porcine small intestinal submucosa (SIS). A total of 24 critical sized defects were created bilaterally in radii of 12 New Zealand White rabbits. TEP/SIS was implanted into the defect site. Bone defect repair was evaluated with radiographic and histological examination at 4, 8 and 12 weeks. Bone defects were structurally reconstructed in the TEP group with mature cortical bone and medullary canals, however this was not observed in the SIS group at 12 weeks. The TEP approach can effectively restore allogenic critical sized defects, and achieve maturity of long-bone structure in 12 weeks in rabbit models.

Influence of residual composition on the structure and properties of extracellular matrix derived hydrogels

In this work, hydrolysates of extracellular matrix (hECM) were obtained from rat tail tendon (TR), bovine Achilles tendon (TAB), porcine small intestinal submucosa (SIS) and bovine pericardium (PB), and they were polymerized to generate ECM hydrogels. The composition of hECM was evaluated by quantifying the content of sulphated glycosaminoglycans (sGAG), fibronectin and laminin. The polymerization process, structure, physicochemical properties, in vitro degradation and biocompatibility were studied and related to their composition. The results indicated that the hECM derived from SIS and PB were significantly richer in sGAG, fibronectin and laminin, than those derived from TAB and TR. These differences in hECM composition influenced the polymerization and the structural characteristics of the fibrillar gel network. Consequently, the swelling, mechanics and degradation of the hydrogels showed a direct relationship with the remaining composition. Moreover, the cytocompatibility and the secretion of transforming growth factor beta-1 (TGF-β1) by macrophages were enhanced in hydrogels with the highest residual content of ECM biomolecules. The results of this work evidenced the role of the ECM molecules remaining after both decellularization and hydrolysis steps to produce tissue derived hydrogels with structure and properties tailored to enhance their performance in tissue engineering and regenerative medicine applications.

Effect of porcine small intestinal submucosa extracellular matrix in promoting vitality and functional gene expression of hepatocyte

To investigate the effect of porcine small intestinal submucosa extracellular matrix (PSISM) on the vitality and gene regulation of hepatocyte so as to lay the experimental foundation for the application of PSISM in liver tissue engineering. The experiment was divided into two parts: ① BRL cells were cultured with 50, 100, and 200 μg/mL PSISM-medium which were prepared by adding PSISM into the H-DMEM-medium containing 10%FBS in groups A1, B1, and C1, and simple H-DMEM-medium served as a control (group D1); ② BRL cells were seeded on 1%, 2%, and 3% PSISM hydrogel which were prepared by dissolving PSISM in sterile PBS solution containing 0.1 mol/L NaOH in groups A2, B2, and C2, and collagen type I gel served as a control (group D2). At 1, 3, and 5 days after culture, the morphology and survival of liver cells were detected by the Live/Dead fluorescent staining. The cell vitality was tested by cell counting kit-8 (CCK-8) assay. And the relative expressions of albumin (ALB), cytokeratin 18 (CK18), and alpha-fetoprotein (AFP) in hepatocytes were determined by real-time fluorescent quantitative PCR (RT-qPCR). The Live/Dead fluorescent staining showed the cells survived well in all groups. CCK-8 results displayed that the absorbance ( A) value of group C1 was significantly higher than that of group D1 at 5 days after culture with PSISM-medium, and there was no significant difference between groups at other time points ( P>0.05). After cultured with PSISM hydrogels, the A values of groups A2, B2, and C2 were significantly higher than those of group D2 at 3 and 5 days ( P<0.05), the A value of group A2 was significantly higher than that of groups B2 and C2 at 5 days ( P<0.05), but there was no significant difference between groups at other time points ( P>0.05). RT-qPCR showed that the relative expressions of ALB and CK18 mRNA significantly increased and the relative expression of AFP mRNA significantly decreased in groups A1, B1, and C1 when compared with group D1 ( P<0.05). The relative expression of CK18 mRNA in group C1 was significantly lower than that in groups A1 and B1 ( P<0.05). The relative expressions of ALB and CK18 mRNA were significantly higher and the relative expression of AFP mRNA was significantly lower in groups A2, B2, and C2 than group D2 ( P<0.05); the relative expression of CK18 mRNA in group A2 was significantly higher than that in group B2 ( P<0.05), and the relative expression of AFP mRNA in group A2 was significantly lower than that in group C2 ( P<0.05), but no significant difference was found between other groups ( P>0.05). PSISM has good compatibility with hepatocyte and can promote the vitality and functional gene expression of hepatocyte. PSISM is expected to be used as culture medium supplement or cell carrier for liver tissue engineering.

Enhanced tissue remodelling efficacy of adipose-derived mesenchymal stem cells using injectable matrices in radiation-damaged salivary gland model.

The present study was conducted to introduce the use of a delivery carrier for local transplantation of human adipose tissue-derived mesenchymal stem cells (AdMSCs) into the salivary gland (SG) and analyse its ability to enhance radioprotection of AdMSCs against irradiation (IR)-induced damage. An injectable porcine small intestinal submucosa (SIS) matrix was used as a cell delivery carrier, and human AdMSCs were contained within SIS hydrogel (AdMSC/SIS). After local injection into SGs of mice following local IR, morphological and functional changes were evaluated in the sham, vehicle [phosphate-buffered saline (PBS)], SIS, AdMSC and AdMSC/SIS groups. Local transplantation of AdMSC resulted in less fibrosis, regardless of the use of a carrier, but the AdMSC/SIS group showed more mucin-producing acini relative to those in the PBS group. Functional restoration of salivation capacity and salivary protein synthesis was achieved in AdMSC and AdMSC/SIS groups, with a greater tendency being observed in the AdMSC/SIS group. AdMSC treatment resulted in tissue remodelling with a greater number of salivary epithelial cells (AQP-5), SG progenitor cells (c-Kit), endothelial cells (CD31) and myoepithelial cells (α-SMA), among which endothelial and myoepithelial cells significantly increased in the AdMSC/SIS group relative to the AdMSC group. AdMSC treatment alleviated IR-induced cell death, and the anti-apoptotic and anti-oxidative effects of AdMSC were enhanced in the AdMSC/SIS group relative to the AdMSC group. These results suggest local transplantation of AdMSC improves tissue remodelling following radiation damage in SG tissue, and that use of a carrier enhances the protective effects of AdMSC-mediated cellular protection against IR via paracrine secretion. Copyright © 2016 John Wiley & Sons, Ltd.

Manufacture and preparation of human placenta-derived mesenchymal stromal cells for local tissue delivery

BackgroundIn this study we describe the development of a Current Good Manufacturing Practice (CGMP)-compliant process to isolate, expand and bank placenta-derived mesenchymal stromal cells (PMSCs) for use as stem cell therapy. We characterize the viability, proliferation and neuroprotective secretory profile of PMSCs seeded on clinical-grade porcine small intestine submucosa extracellular matrix (SIS-ECM; Cook Biotech). MethodsPMSCs were isolated from early gestation placenta chorionic villus tissue via explant culture. Cells were expanded, banked and screened. Purity and expression of markers of pluripotency were determined using flow cytometry. Optimal loading density and viability of PMSCs on SIS-ECM were determined using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) cell proliferation and fluorescent live/dead assays, respectively. Growth factors secretion was analyzed using enzyme-linked immunosorbent assays (ELISA). ResultsPMSCs were rapidly expanded and banked. Viable Master and Working Cell Banks were stable with minimal decrease in viability at 6 months. All PMSCs were sterile, free from Mycoplasma species, karyotypically normal and had low endotoxin levels. PMSCs were homogeneous by immunophenotyping and expressed little to no pluripotency markers. Optimal loading density on SIS-ECM was 3–5 × 105 cells/cm2, and seeded cells were >95% viable. Neurotrophic factor secretion was detectable from PMSCs seeded on plastic and SIS-ECM with variability between donor lots. DiscussionPMSCs from early gestation placental tissues can be rapidly expanded and banked in stable, viable cell banks that are free from contaminating agents, genetically normal and pure. PMSC delivery can be accomplished by using SIS-ECM, which maintains cell viability and protein secretion. Future work in vivo is necessary to optimize cell seeding and transplantation to maximize therapeutic capabilities.

An injectable nucleus pulposus cell-modified decellularized scaffold: biocompatible material for prevention of disc degeneration.

We developed a nucleus pulposus cell (NPC)-modulated decellularized small intestinal submucosa (SIS) scaffold, and assessed the ability of this material to prevent Intervertebral disc degeneration (IVD) degeneration. Decellularized porcine SIS was squashed into particles and the biological safety and efficiency of these particles were evaluated. Next, SIS particles were seeded with rabbit NPCs, cultured for two months in vitro, decellularized again and suspended for intervertebral injection. We demonstrated that use of the decellularization protocol resulted in the removal of cellular components with maximal retention of extracellular matrix. The xenogeneic decellularized SIS did not display cytotoxicity in vitro and its application prevented NPC degradation. Furthermore, the xenogeneic SIS microparticles were effective in preventing IVD progression in vivo in a rabbit disc degeneration model. In conclusion, our study describes an optimized method for decellularized SIS preparation and demonstrated that the material is safe and effective for treating IVD degeneration.

Acellular Biological Scaffold Repair Does Not Overcome the Pathobiology of Volumetric Muscle Loss Injury

Volumetric muscle loss (VML) resulting from extremity trauma presents chronic and persistent functional deficits, restricted joint range of motion, and fibrosis, which ultimately manifest disability. Currently, there is a clinical need for therapies aimed at addressing the debilitating outcomes due to VML injuries. Recent investigations have examined the use of commercially available biological scaffolds as a regenerative medicine approach for VML. However, there is a paucity of large animal data to advance clinical translation. We hypothesized that repair of VML injuries with an acellular biologic scaffold would improve function, specifically neuromuscular strength following injury. To test this hypothesis, female Yorkshire Cross pigs (n=10) were randomized to sham or an ~20% VML injury to the peroneous tertius muscle, and injuries were left non‐repaired, or surgically repaired with an acellular biologic scaffold derived from either porcine small intestinal submucosa (SIS) or urinary bladder matrix (UBM) using standard clinical surgical implantation procedures. Analysis of muscle volume using CT imaging and muscle function via peroneal nerve stimulation was conducted through 12 weeks post‐injury. At this terminal time‐point, full thickness biopsy samples were used for histological analysis and sequencing of RNA extracted from the injured muscle tissue. All studies were conducted in compliance with the Animal Welfare Act, the Implementing Animal Welfare Regulations and in accordance with the principles of the Guide for the Care and Use of Laboratory Animals. Unexpected adverse advents occurred in 80% of the VML injuries repaired with the SIS scaffold. Both the repair with SIS and UBM resulted in a significant fibrotic response and increased volume of the anterior compartment. However, this volume could not be attributed to increased muscle, as histologic analysis of the muscle indicated sub‐physiologic islands of muscle fibers (~50 fibers). To understand the quality of muscle, peak muscle torque was normalized to the CT‐derived volume of the anterior compartment at 10 weeks post‐injury. Collectively in the non‐ and ECM‐repaired limbs there was ~45% deficit compared to sham operated limbs. Additionally, in both the non‐ and ECM‐repaired limbs there was an ~30% deficit in absolute peak isometric torque through 12 weeks post‐injury. Tissue level RNA sequencing analysis of the non‐repaired and surgically repaired samples compared to Sham controls revealed increases in expression of sets of genes associated with inflammatory signaling and fibrogenesis and downregulation of myogenic repair gene sets. Quantitative comparison of the transcriptomes from surgically repaired samples against the non‐repaired samples indicated high degrees of correlation amongst the differentially expressed genes. These results indicate the gene expression programs induced from a VML insult are not appreciably augmented when treated with surgical repair of an acellular biologic scaffold. Collectively, these data indicate that VML results in extensive and continued disruption of the remaining musculature and that ECM repair does not ameliorate the resulting pathobiology.