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Liu C, Lin Z, Ruan W, Gai X, Qu Q, Wang C, Zhu F, Sun X, Zhang J. Safety and tissue remodeling assay of small intestinal submucosa meshes using a modified porcine surgical hernia model. Sci Rep 2024; 13:23108. [PMID: 38172186 PMCID: PMC10764949 DOI: 10.1038/s41598-023-50425-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024] Open
Abstract
In studies to date, meshes based on extracellular matrix (ECM) have been extensively used in clinical applications. Unfortunately, little is known about the function of the immunogenic residual, absorbable profile during the tissue repair process. Moreover, there needs to be a recognized preclinical animal model to investigate the safety and efficacy of extracellular matrix meshes. Herein, we designed and fabricated a kind of SIS mesh followed by a scanned electron micrograph characterization and tested α-Gal antigen clearance rate and DNA residual. In order to prove the biocompatibility of the SIS mesh, cell viability, chemotaxis assay and local tissue reaction were assessed by MTT and RTCA cytotoxicity test in vitro as well as implantation and degradation experiments in vivo. Furthermore, we developed a stable preclinical animal model in the porcine ventral hernia repair investigation, which using laparoscopic plus open hybridization method to evaluate tissue adhesion, explant mechanical performance, and histologic analysis after mesh implantation. More importantly, we established a semi-quantitative scoring system to examine the ECM degradation, tissue remodeling and regeneration in the modified porcine surgical hernia model for the first time. Our results highlight the application prospect of the improved porcine ventral hernia model for the safety and efficacy investigation of hernia repair meshes.
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Affiliation(s)
- Chenghu Liu
- Institute of Immunopharmacology and Immunotherapy, School of Pharmaceutical Sciences, Shandong University, 44 Wenhua Xi Rd, Jinan, 250012, Shandong, China
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, NMPA Key Laboratory for Safety Evaluation of Biomaterials and Medical Devices, Jinan, 250101, China
| | - Zhenhua Lin
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, NMPA Key Laboratory for Safety Evaluation of Biomaterials and Medical Devices, Jinan, 250101, China
| | - Wenting Ruan
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, NMPA Key Laboratory for Safety Evaluation of Biomaterials and Medical Devices, Jinan, 250101, China
| | - Xiaoxiao Gai
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, NMPA Key Laboratory for Safety Evaluation of Biomaterials and Medical Devices, Jinan, 250101, China
| | - Qiujin Qu
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, NMPA Key Laboratory for Safety Evaluation of Biomaterials and Medical Devices, Jinan, 250101, China
| | - Changbin Wang
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, NMPA Key Laboratory for Safety Evaluation of Biomaterials and Medical Devices, Jinan, 250101, China
| | - Fuyu Zhu
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, NMPA Key Laboratory for Safety Evaluation of Biomaterials and Medical Devices, Jinan, 250101, China
| | - Xiaoxia Sun
- Shandong Institute of Medical Device and Pharmaceutical Packaging Inspection, NMPA Key Laboratory for Safety Evaluation of Biomaterials and Medical Devices, Jinan, 250101, China
| | - Jian Zhang
- Institute of Immunopharmacology and Immunotherapy, School of Pharmaceutical Sciences, Shandong University, 44 Wenhua Xi Rd, Jinan, 250012, Shandong, China.
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2
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Barsch F, Mamilos A, Babel M, Wagner WL, Winther HB, Schmitt VH, Hierlemann H, Teufel A, Brochhausen C. Semiautomated quantification of the fibrous tissue response to complex three-dimensional filamentous scaffolds using digital image analysis. J Biomed Mater Res A 2021; 110:353-364. [PMID: 34390322 DOI: 10.1002/jbm.a.37293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 06/24/2021] [Accepted: 07/29/2021] [Indexed: 12/12/2022]
Abstract
Fibrosis represents a relevant response to the implantation of biomaterials, which occurs not only at the tissue-material interface (fibrotic encapsulation) but also within the void fraction of complex three-dimensional (3D) biomaterial constructions (fibrotic ingrowth). Usual evaluation of the biocompatibility mostly depicts fibrosis at the interface of the biomaterial using semiquantitative scores. Here, the relations between encapsulation and infiltrating fibrotic growth are poorly represented. Virtual pathology and digital image analysis provide new strategies to assess fibrosis in a more differentiated way. In this study, we adopted a method previously used to quantify fibrosis in visceral organs to the quantification of fibrosis to 3D biomaterials. In a proof-of-concept study, we transferred the "Collagen Proportionate Area" (CPA) analysis from hepatology to the field of biomaterials. As one task of an experimental animal study, we used CPA analysis to quantify the fibrotic ingrowth into a filamentous scaffold after subcutaneous implantation. We were able to demonstrate that the application of the CPA analysis is well suited as an additional fibrosis evaluation strategy for new biomaterial constructions. The CPA method can contribute to a better understanding of the fibrotic interactions between 3D scaffolds and the host tissue responses.
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Affiliation(s)
- Friedrich Barsch
- Institute for Exercise and Occupational Medicine, Faculty of Medicine, Medical Center, University of Freiburg, Freiburg, Germany.,Institute of Pathology, University Regensburg, Regensburg, Germany
| | - Andreas Mamilos
- Institute of Pathology, University Regensburg, Regensburg, Germany
| | - Maximilian Babel
- Institute of Pathology, University Regensburg, Regensburg, Germany.,Central Biobank Regensburg, University Regensburg and University Hospital Regensburg, Regensburg, Germany
| | - Willi L Wagner
- Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany.,Translational Lung Research Centre Heidelberg (TLRC), German Lung Research Centre (DZL), Heidelberg, Germany
| | - Hinrich B Winther
- Institute for Diagnostic and Interventional Radiology, Hannover Medical School, Hannover, Germany
| | - Volker H Schmitt
- Department of Cardiology, Cardiology I, University Medical Center Mainz, Johannes Gutenberg-University of Mainz, Mainz, Germany
| | | | - Andreas Teufel
- Department of Medicine II, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Christoph Brochhausen
- Institute of Pathology, University Regensburg, Regensburg, Germany.,Central Biobank Regensburg, University Regensburg and University Hospital Regensburg, Regensburg, Germany
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3
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Capella-Monsonís H, Zeugolis DI. Decellularized xenografts in regenerative medicine: From processing to clinical application. Xenotransplantation 2021; 28:e12683. [PMID: 33709410 DOI: 10.1111/xen.12683] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 01/28/2021] [Accepted: 02/25/2021] [Indexed: 12/13/2022]
Abstract
Decellularized xenografts are an inherent component of regenerative medicine. Their preserved structure, mechanical integrity and biofunctional composition have well established them in reparative medicine for a diverse range of clinical indications. Nonetheless, their performance is highly influenced by their source (ie species, age, tissue) and processing (ie decellularization, crosslinking, sterilization and preservation), which govern their final characteristics and determine their success or failure for a specific clinical target. In this review, we provide an overview of the different sources and processing methods used in decellularized xenografts fabrication and discuss their effect on the clinical performance of commercially available decellularized xenografts.
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Affiliation(s)
- Héctor Capella-Monsonís
- 1Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland.,Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland
| | - Dimitrios I Zeugolis
- 1Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland.,Science Foundation Ireland (SFI) Centre for Research in Medical Devices (CÚRAM), Biomedical Sciences Building, National University of Ireland Galway (NUI Galway), Galway, Ireland.,Regenerative, Modular & Developmental Engineering Laboratory (REMODEL), Faculty of Biomedical Sciences, Università della Svizzera Italiana (USI), Lugano, Switzerland
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Amigo N, Zubieta C, Riganti JM, Ramirez M, Renda P, Lovera R, Pascaner A, Vigliano C, Craiem D, Young DA, Gilbert TW, Nieponice A. Biomechanical Features of Reinforced Esophageal Hiatus Repair in a Porcine Model. J Surg Res 2020; 246:62-72. [DOI: 10.1016/j.jss.2019.08.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/24/2019] [Accepted: 08/29/2019] [Indexed: 12/18/2022]
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Urinary Bladder Matrix Scaffolds Promote Pericardium Repair in a Porcine Model. J Surg Res 2020; 249:216-224. [PMID: 32001387 DOI: 10.1016/j.jss.2019.12.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 11/14/2019] [Accepted: 12/27/2019] [Indexed: 01/01/2023]
Abstract
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.
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Keating JH, Melidone R, Garcia-Polite F. Preclinical Evaluation of Mesh Implants: The Pathologist’s Perspective. Toxicol Pathol 2018; 47:379-389. [DOI: 10.1177/0192623318811592] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Surgical and laparoscopic implantation of mesh devices is on the rise for a variety of applications. The complexity and range of evolving mesh designs calls for consistent and detailed pathologic evaluation in determining host responses and assessing overall safety. This review addresses the components of evaluation of mesh implants in animal models, with emphasis on histologic parameters, semiquantitative scoring matrices, and morphometric analyses that have been specifically adapted to this class of implants. Necropsy assessment should include implant persistence, architecture, and associated host responses such as exudation and adhesions. Microscopic evaluation should focus on primary relevant responses such as bioresorption, integration/tissue ingrowth, neovascularization, and inflammation. Selection of the best means of processing and evaluation can be complicated, as meshes may include one or more biologic components (e.g., collagen), synthetic polymer fibers, coatings, and other molecules. The architecture of some meshes can influence tissue responses and complicate sampling, sectioning, and evaluation. Recognition of specific study objectives and knowledge of anticipated responses helps to determine the appropriate histologic or immunochemical stains, while understanding of mesh composition and anticipated persistence in tissue determines the suitability of paraffin or resin embedding, and both guide the evaluation of mesh devices in the preclinical setting.
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Ha A, Criman ET, Kurata WE, Matsumoto KW, Pierce LM. Evaluation of a Novel Hybrid Viable Bioprosthetic Mesh in a Model of Mesh Infection. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2017; 5:e1418. [PMID: 28894654 PMCID: PMC5585427 DOI: 10.1097/gox.0000000000001418] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 05/30/2017] [Indexed: 01/01/2023]
Abstract
Background: The reported incidence of mesh infection in contaminated operative fields is as high as 30% regardless of material used. Our laboratory previously showed that augmenting acellular bioprosthetic mesh with allogeneic mesenchymal stem cells (MSC) enhances resistance to bacterial colonization in vivo and preserves mesh integrity. This study’s aim was to determine whether augmentation of non-crosslinked porcine dermis (Strattice) with commercially available, cryopreserved, viable MSC-containing human placental tissue (Stravix) similarly improves infection resistance after inoculation with Escherichia coli (E. coli) using an established mesh infection model. Methods: Stravix was thawed per manufacturer’s instructions and 2 samples were tested for cell viability using a Live/Dead Cell assay at the time of surgery. Rats (N = 20) were implanted subcutaneously with 1 piece of Strattice and 1 piece of hybrid mesh (Strattice + Stravix sutured at the corners). Rats were inoculated with either sterile saline or 106 colony-forming units of E. coli before wound closure (n = 10 per group). At 4 weeks, explants underwent microbiologic and histologic analyses. Results: In E. coli–inoculated animals, severe or complete mesh degradation concurrent with abscess formation was observed in 100% (10/10) hybrid meshes and 90% (9/10) Strattice meshes. Histologic evaluation determined that meshes inoculated with E. coli exhibited severe acute inflammation, which correlated with bacterial recovery (P < 0.001). Viability assays performed at the time of surgery failed to verify the presence of numerous live cells in Stravix. Conclusions: Stravix cryopreserved MSC-containing human umbilical tissue does not improve infection resistance of a bioprosthetic mesh in vivo in rats after inoculation with E. coli.
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Affiliation(s)
- Ally Ha
- Department of General Surgery, Tripler Army Medical Center, Honolulu, H.I.; and Department of Clinical Investigation, Tripler Army Medical Center, Honolulu, H.I
| | - Erik T Criman
- Department of General Surgery, Tripler Army Medical Center, Honolulu, H.I.; and Department of Clinical Investigation, Tripler Army Medical Center, Honolulu, H.I
| | - Wendy E Kurata
- Department of General Surgery, Tripler Army Medical Center, Honolulu, H.I.; and Department of Clinical Investigation, Tripler Army Medical Center, Honolulu, H.I
| | - Karen W Matsumoto
- Department of General Surgery, Tripler Army Medical Center, Honolulu, H.I.; and Department of Clinical Investigation, Tripler Army Medical Center, Honolulu, H.I
| | - Lisa M Pierce
- Department of General Surgery, Tripler Army Medical Center, Honolulu, H.I.; and Department of Clinical Investigation, Tripler Army Medical Center, Honolulu, H.I
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8
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Sahoo S, Baker AR, Haskins IN, Krpata DM, Rosen MJ, Derwin KA. Assessment of Human Acellular Dermis Graft in Porcine Models for Ventral Hernia Repair. Tissue Eng Part C Methods 2017; 23:718-727. [PMID: 28602151 DOI: 10.1089/ten.tec.2017.0238] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE Preclinical evaluation of hernia meshes is commonly performed in porcine models. We recently developed two surgically induced porcine hernia models-an incisional and an excisional model-that formed persistent hernias in the absence of graft repair. Herein, we investigate if these models will continue to form a hernia after graft repair. MATERIALS AND METHODS Ten pigs were used to create two hernia models-a 10-cm partial-thickness incisional defect (n = 5) and an 8 × 8-cm full-thickness excisional defect (n = 5). The defects were repaired using a 12 × 12-cm human acellular dermis graft placed in a preperitoneal/retrorectus sublay position and fixed using transfascial sutures. Postoperative management included the use of suction drainage for 1 week and an abdominal binder for 4 weeks in the more severe excisional model. Hernia development was assessed clinically, and hernia defect size and volume were measured using postoperative computed tomography (CT) imaging over 12 weeks. Radiographic inflation testing (2 L inflation), biaxial mechanical testing, and histological evaluation were also performed at 12 weeks. RESULTS All pigs with the excisional model, but none with the incisional model, developed a clinically relevant hernia. At the end of 12 weeks, the excisional model had a significantly greater hernia defect size (259 ± 51 cm2 vs. 47 ± 16 cm2) and repair volume (865 ± 414 cm3 vs. 85 ± 52 cm3) compared with the incisional model. The excisional model also showed an order of magnitude greater increase in repair volume (280 cm3 vs. 47 cm3) compared with the incisional model upon 2 L inflation. Furthermore, the excisional model showed a trend of having higher dilatational strain at average biaxial load of 250 N and lower stiffness compared with the incisional model. The excisional model had a thin, hypercellular hernia sac spanning the defect, whereas the incisional model had a thick densely fibrotic scar bridging the defect. CONCLUSION The 8 × 8-cm excisional defect model, together with appropriate postoperative wound management, in the pig model is recommended for preclinical investigation of different grafts for hernia repair. Novel CT imaging and biomechanical testing methods are recommended to measure functional outcomes of hernia repair in preclinical models.
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Affiliation(s)
- Sambit Sahoo
- 1 Department of Biomedical Engineering, Lerner Research Institute , Cleveland Clinic, Cleveland, Ohio
| | - Andrew R Baker
- 1 Department of Biomedical Engineering, Lerner Research Institute , Cleveland Clinic, Cleveland, Ohio
| | - Ivy N Haskins
- 2 Comprehensive Hernia Center, Digestive Disease and Surgery Institute , Cleveland Clinic, Cleveland, Ohio
| | - David M Krpata
- 2 Comprehensive Hernia Center, Digestive Disease and Surgery Institute , Cleveland Clinic, Cleveland, Ohio
| | - Michael J Rosen
- 2 Comprehensive Hernia Center, Digestive Disease and Surgery Institute , Cleveland Clinic, Cleveland, Ohio
| | - Kathleen A Derwin
- 1 Department of Biomedical Engineering, Lerner Research Institute , Cleveland Clinic, Cleveland, Ohio
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Kahan LG, Lake SP, McAllister JM, Tan WH, Yu J, Thompson D, Brunt LM, Blatnik JA. Combined in vivo and ex vivo analysis of mesh mechanics in a porcine hernia model. Surg Endosc 2017; 32:820-830. [DOI: 10.1007/s00464-017-5749-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 07/14/2017] [Indexed: 12/29/2022]
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10
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Kahan LG, Guertler C, Blatnik JA, Lake SP. Validation of Single C-Arm Fluoroscopic Technique for Measuring In Vivo Abdominal Wall Deformation. J Biomech Eng 2017; 139:2633404. [DOI: 10.1115/1.4037073] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Indexed: 11/08/2022]
Abstract
Hernia meshes significantly reduce the recurrence rates in hernia repair. It is known that they affect the abdominal wall postimplantation, yet the understanding of in vivo mechanics in the mesh placement area is lacking. We established a single C-arm biplane fluoroscopic system to study strains at the interface between the mesh and repaired abdominal tissues. We aimed to validate this system for future porcine hernia repair studies. Custom matlab programs were written to correct for pincushion distortion, and direct linear transformation (DLT) reconstructed objects in 3D. Using a custom biplane-trough setup, image sets were acquired throughout the calibrated volume to evaluate a radio-opaque test piece with known distances between adjacent beads. Distances were measured postprocessing and compared to known measurements. Repeatability testing was conducted by taking image sets of the test piece in a fixed location to determine system movement. The error in areal stretch tracking was evaluated by imaging a square plate with fixed radio-opaque beads and using matlab programs to compare the measured areal stretch to known bead positions. Minor differences between measured and known distances in the test piece were not statistically different, and the system yielded a 0.01 mm bias in the XY plane and a precision of 0.61 mm. The measured areal stretch was 0.996, which was not significantly different than the expected value of 1. In addition, preliminary stretch data for a hernia mesh in a porcine model demonstrated technique feasibility to measure in vivo porcine abdominal mechanics.
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Affiliation(s)
- Lindsey G. Kahan
- Department of Surgery, Washington University in St. Louis School of Medicine, St. Louis, MO 63130 e-mail:
| | - Charlotte Guertler
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO 63130 e-mail:
| | - Jeffrey A. Blatnik
- Department of Surgery, Washington University in St. Louis School of Medicine, St. Louis, MO 63130 e-mail:
| | - Spencer P. Lake
- Mem. ASME Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, 1 Brookings Drive, Campus Box 1185, St. Louis, MO 63130
- Department of Orthopaedic Surgery, Washington University in St. Louis, 1 Brookings Drive, Campus Box 1185, St. Louis, MO 63130
- Department of Biomedical Engineering, Washington University in St. Louis, 1 Brookings Drive, Campus Box 1185, St. Louis, MO 63130 e-mail:
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Development of a critical-sized ventral hernia model in the pig. J Surg Res 2017; 210:115-123. [DOI: 10.1016/j.jss.2016.10.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 09/17/2016] [Accepted: 10/27/2016] [Indexed: 11/23/2022]
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12
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Bone Marrow-Derived Mesenchymal Stem Cells Enhance Bacterial Clearance and Preserve Bioprosthetic Integrity in a Model of Mesh Infection. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2016; 4:e751. [PMID: 27482490 PMCID: PMC4956863 DOI: 10.1097/gox.0000000000000765] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 04/20/2016] [Indexed: 12/27/2022]
Abstract
Background: The reported incidence of mesh infection in contaminated operative fields is as high as 30% regardless of the material used. Recently, mesenchymal stem cells (MSCs) have been shown to possess favorable immunomodulatory properties and improve tissue incorporation when seeded onto bioprosthetics. The aim of this study was to evaluate whether seeding noncrosslinked bovine pericardium (Veritas Collagen Matrix) with allogeneic bone marrow–derived MSCs improves infection resistance in vivo after inoculation with Escherichia coli (E. coli). Methods: Rat bone marrow–derived MSCs at passage 3 were seeded onto bovine pericardium and cultured for 7 days before implantation. Additional rats (n = 24) were implanted subcutaneously with MSC-seeded or unseeded mesh and inoculated with 7 × 105 colony-forming units of E. coli or saline before wound closure (group 1, unseeded mesh/saline; group 2, unseeded mesh/E. coli; group 3, MSC-seeded mesh/E. coli; 8 rats per group). Meshes were explanted at 4 weeks and underwent microbiologic and histologic analyses. Results: MSC-seeded meshes inoculated with E. coli demonstrated superior bacterial clearance and preservation of mesh integrity compared with E. coli–inoculated unseeded meshes (87.5% versus 0% clearance; p = 0.001). Complete mesh degradation concurrent with abscess formation was observed in 100% of rats in the unseeded/E. coli group, which is in contrast to 12.5% of rats in the MSC-seeded/E. coli group. Histologic evaluation determined that remodeling characteristics of E. coli–inoculated MSC-seeded meshes were similar to those of uninfected meshes 4 weeks after implantation. Conclusions: Augmenting a bioprosthetic material with stem cells seems to markedly enhance resistance to bacterial infection in vivo and preserve mesh integrity.
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Cell-coating affects tissue integration of synthetic and biologic meshes: comparative analysis of the onlay and underlay mesh positioning in rats. Surg Endosc 2016; 30:4445-53. [DOI: 10.1007/s00464-016-4764-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 01/11/2016] [Indexed: 10/22/2022]
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14
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Holihan JL, Bondre I, Askenasy EP, Greenberg JA, Keith JN, Martindale RG, Roth JS, Liang MK. Sublay versus underlay in open ventral hernia repair. J Surg Res 2015; 202:26-32. [PMID: 27083944 DOI: 10.1016/j.jss.2015.12.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/03/2015] [Accepted: 12/11/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND The ideal location for mesh placement in open ventral hernia repair (OVHR) remains under debate. Current trends lean toward underlay or sublay repair. We hypothesize that in patients undergoing OVHR, sublay versus underlay placement of mesh results in fewer surgical site infections (SSIs) and recurrences. MATERIALS AND METHODS A multi-institution database of all OVHRs performed from 2010 to 2011 was accessed. Patients with mesh placed in the sublay or underlay position and at least 1 mo of follow-up were included. Primary outcome was SSI. Secondary outcome was hernia recurrence. Multivariate analysis was performed using logistic regression for SSI and Cox regression for recurrence. Subgroup analysis of elective, midline ventral incisional hernias was also performed. RESULTS Of 447 patients, 139 (31.1%) had a sublay repair. The unadjusted analysis showed no difference in SSI and lower recurrence using sublay compared with underlay. On multivariate analysis, there was no difference in SSI using sublay compared with underlay (odds ratio 1.5, 95% confidence interval [CI] 0.8-2.8). Recurrence was less common with sublay (hazard ratio 0.4, 95% CI 0.2-0.8). On subgroup analysis of elective, midline incisional hernias only (n = 247), there were more SSIs with sublay compared with underlay repair (28.0% versus 15.1%, P = 0.018); however, there was no difference in major SSI (sublay 9.3% versus underlay 5.8%, P = 0.315). There were fewer recurrences using sublay repair compared with underlay repair (10.7% versus 25.0%, P = 0.010). CONCLUSIONS In this multi-center, risk-adjusted study, sublay repair was associated with fewer recurrences than underlay repair and no difference in SSI. Randomized controlled trials are warranted to validate these findings.
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Affiliation(s)
- J L Holihan
- Department of Surgery, University of Texas Health Science Center, Houston, Texas.
| | - Ioana Bondre
- Department of Surgery, University of Texas Health Science Center, Houston, Texas
| | - Erik P Askenasy
- Department of Surgery, Baylor College of Medicine, Houston, Texas
| | | | - J N Keith
- Department of Surgery, University of Iowa, Iowa City, Iowa
| | - Robert G Martindale
- Department of Surgery, Oregon Health and Science University, Portland, Oregon
| | - J Scott Roth
- Department of Surgery, University of Kentucky, Lexington, Kentucky
| | - Mike K Liang
- Department of Surgery, University of Texas Health Science Center, Houston, Texas
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15
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Remodeling characteristics and collagen distribution in biological scaffold materials explanted from human subjects after abdominal soft tissue reconstruction: an analysis of scaffold remodeling characteristics by patient risk factors and surgical site classifications. Ann Surg 2015; 261:405-15. [PMID: 24374547 DOI: 10.1097/sla.0000000000000471] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVE The study purpose was to evaluate the associations between patient characteristics or surgical site classifications and the histologic remodeling scores of biologic meshes biopsied from abdominal soft tissue repair sites in the first attempt to generate a multivariable risk-prediction model of nonconstructive remodeling. BACKGROUND Host characteristics and surgical site assessments may predict remodeling degree for biologic meshes used to reinforce abdominal tissue repair sites. METHODS Biologic meshes were biopsied from the abdominal tissue repair sites of n = 40 patients during an abdominal reexploration, stained with hematoxylin and eosin, and evaluated according to a semi-quantitative scoring system for remodeling characteristics (cell types, cell infiltration, extracellular matrix deposition, scaffold degradation, fibrous encapsulation, and neovascularization) and a mean composite score. Biopsies were stained with Sirius Red and Fast Green and analyzed to determine the collagen I:III ratio. On the basis of univariate analyses between subject clinical characteristics or surgical site classification and the histologic remodeling scores, cohort variables were selected for multivariable regression models using P ≤ 0.200. RESULTS The model selection process for cell infiltration score yielded 2 variables: age at mesh implantation and mesh classification (C statistic = 0.989). For the mean composite score, the model selection process yielded 2 variables: age at mesh implantation and mesh classification (r = 0.449). CONCLUSIONS These preliminary results constitute the first steps in generating a risk-prediction model that predicts the patients and clinical circumstances most likely to experience nonconstructive remodeling of abdominal tissue repair sites with biologic mesh reinforcement.
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Blood vessel matrix seeded with cells: a better alternative for abdominal wall reconstruction-a long-term study. BIOMED RESEARCH INTERNATIONAL 2015; 2015:890613. [PMID: 25705696 PMCID: PMC4326343 DOI: 10.1155/2015/890613] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 12/31/2014] [Indexed: 01/07/2023]
Abstract
PURPOSE The aim of this study was to present abdominal wall reconstruction using a porcine vascular graft seeded with MSC (mesenchymal stem cells) on rat model. MATERIAL AND METHODS Abdominal wall defect was prepared in 21 Wistar rats. Acellular porcine-vascular grafts taken from aorta and prepared with Triton X were used. 14 aortic grafts were implanted in place, of which 7 grafts were seeded with rat MSC cells (Group I), and 7 were acellular grafts (Group II). As a control, 7 standard polypropylene meshes were used for defect augmentation (Group III). The assessment method was performed by HE and CD31 staining after 6 months. The mechanical properties have been investigated by Zwick&Roell Z0.5. RESULTS The strongest angiogenesis and lowest inflammatory response were observed in Group I. Average capillaries density was 2.75, 0.75, and 1.53 and inflammatory effect was 0.29, 1.39, and 2.72 for Groups I, II, and III, respectively. The means of mechanical properties were 12.74 ± 1.48, 7.27 ± 1.56, and 14.4 ± 3.7 N/cm in Groups I and II and control, respectively. CONCLUSIONS Cell-seeded grafts have better mechanical properties than acellular grafts but worse than polypropylene mesh. Cells improved mechanical and physiological properties of decellularized natural scaffolds.
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Pore size and pore shape--but not mesh density--alter the mechanical strength of tissue ingrowth and host tissue response to synthetic mesh materials in a porcine model of ventral hernia repair. J Mech Behav Biomed Mater 2014; 42:186-97. [PMID: 25486631 DOI: 10.1016/j.jmbbm.2014.11.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 10/24/2014] [Accepted: 11/03/2014] [Indexed: 01/05/2023]
Abstract
BACKGROUND Over 100 types of soft tissue repair materials are commercially available for hernia repair applications. These materials vary in characteristics such as mesh density, pore size, and pore shape. It is difficult to determine the impact of a single variable of interest due to other compounding variables in a particular design. Thus, the current study utilized prototype meshes designed to evaluate each of these mesh parameters individually. METHODS Five prototype meshes composed of planar, monofilament polyethylene terephthalate (PET) were evaluated in this study. The meshes were designed to focus on three key parameters, namely mesh density, pore size, and pore shape. The prototype meshes were implanted in the preperitoneal, retrorectus space in a porcine model of ventral incisional hernia repair, and tissue ingrowth characteristics were evaluated after 90 days. Mesh-tissue composite specimens were obtained from each repair site and evaluated via T-peel mechanical testing. Force-displacement data for each T-peel test were analyzed and five characteristics of tissue ingrowth reported: peak force (fp), critical force (fc), fracture energy (Γc), work (W), and work density (Wden). Hematoxylin and eosin (H&E) stained sections of explanted mesh-tissue composites were also assessed for characteristics of tissue response including cellular infiltration, cell types, inflammatory response, extracellular matrix deposition, neovascularization, and fibrosis, with a composite score assigned to represent overall tissue response. RESULTS The medium-weight, very large pore, hexagonal (MWVLH) mesh performed significantly better than the light-weight, medium pore, diamond (LWMD) mesh for all parameters evaluated (fp, fc, Γc, W, Wden) and trended toward better results than the medium-weight, medium pore, diamond (MWMD) mesh for the majority of the parameters evaluated. When the data for the five meshes was grouped to evaluate mesh density, pore size, and pore shape, differences were more pronounced. No significant differences were observed with respect to mesh density, however significant improvement in mechanical strength of tissue ingrowth occurred as pore size increased from medium to very large. In addition, the hexagonal pores resulted in the strongest tissue ingrowth, followed by the square pores, and finally the diamond pores. Scores for several histological parameters were significantly different for these prototype meshes. For example, the MWVLH mesh showed significantly greater tissue ingrowth by neovascularization histological score than MWMD and MWVLS meshes (p<0.05) and significantly less fibrosis than LWMD and MWVLS meshes (p<0.05). CONCLUSION Pore shape and pore size significantly altered the mechanical strength of tissue ingrowth and host-site integration in a porcine model of ventral hernia repair, while mesh density had no effect.
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Stoikes N, Sharpe J, Tasneem H, Roan E, Paulus E, Powell B, Webb D, Handorf C, Eckstein E, Fabian T, Voeller G. Biomechanical evaluation of fixation properties of fibrin glue for ventral incisional hernia repair. Hernia 2013; 19:161-6. [DOI: 10.1007/s10029-013-1163-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 09/14/2013] [Indexed: 11/28/2022]
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Effect of Cross-Linked and Non–Cross-Linked Acellular Dermal Matrices on the Expression of Mediators Involved in Wound Healing and Matrix Remodeling. Plast Reconstr Surg 2013; 131:697-705. [DOI: 10.1097/prs.0b013e3182818a3d] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Jenkins ED, Lerdsirisopon S, Costello KP, Melman L, Greco SC, Frisella MM, Matthews BD, Deeken CR. Laparoscopic fixation of biologic mesh at the hiatus with fibrin or polyethylene glycol sealant in a porcine model. Surg Endosc 2011; 25:3405-13. [PMID: 21594740 PMCID: PMC3826827 DOI: 10.1007/s00464-011-1741-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 04/15/2011] [Indexed: 01/12/2023]
Abstract
BACKGROUND The objective of this study was to determine the acute and chronic fixation strengths achieved by fibrin or polyethylene glycol (PEG) sealants to secure biologic mesh at the esophageal hiatus in a porcine model. METHODS For this study, 32 female domestic pigs were divided into four groups of 8 each. The four groups respectively received acute fibrin sealant, acute PEG sealant, chronic fibrin sealant, and chronic PEG sealant. Laparoscopically, a 5.5 × 8.5-cm piece of Biodesign Surgisis Hiatal Hernia Graft (porcine small intestine submucosa) was oriented with the U-shaped cutout around the gastroesophageal junction and the short axis in the craniocaudal direction to simulate hiatal reinforcement with a biologic mesh. The mesh then was secured with 2 ml of either fibrin sealant or PEG sealant. The pigs in the acute groups were maintained alive for 2 h to allow for complete polymerization of the sealants, and the pigs in the chronic group were maintained alive for 14 days. After the pigs were euthanized, specimens of the mesh-tissue interface were subjected to lap shear testing to determine fixation strength, and hematoxylin and eosin (H&E) stained slides were evaluated for evidence of remodeling. RESULTS No significant differences were observed between the acute and chronic fixation strengths or the remodeling characteristics of the two sealants. However, fixation strength increased significantly over time for both types of sealant. Evidence of remodeling also was significantly more pronounced in the chronic specimens than in the acute specimens. CONCLUSIONS This study demonstrated the feasibility of using fibrin or PEG sealants to secure biologic mesh at the hiatus in a porcine model.
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Affiliation(s)
- Eric D. Jenkins
- Department of Surgery, Section of Minimally Invasive Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO 63110, USA
| | - Sopon Lerdsirisopon
- Department of Surgery, Section of Minimally Invasive Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO 63110, USA
| | - Kevin P. Costello
- Department of Surgery, Section of Minimally Invasive Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO 63110, USA
| | - Lora Melman
- Department of Surgery, Section of Minimally Invasive Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO 63110, USA
| | - Suellen C. Greco
- Division of Comparative Medicine, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis MO 63110, USA
| | - Margaret M. Frisella
- Department of Surgery, Section of Minimally Invasive Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO 63110, USA
| | - Brent D. Matthews
- Department of Surgery, Section of Minimally Invasive Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO 63110, USA
| | - Corey R. Deeken
- Department of Surgery, Section of Minimally Invasive Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO 63110, USA
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Deeken CR, Matthews BD. Comparison of contracture, adhesion, tissue ingrowth, and histologic response characteristics of permanent and absorbable barrier meshes in a porcine model of laparoscopic ventral hernia repair. Hernia 2011; 16:69-76. [DOI: 10.1007/s10029-011-0854-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 06/24/2011] [Indexed: 01/29/2023]
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Biomechanical and histologic evaluation of fenestrated and nonfenestrated biologic mesh in a porcine model of ventral hernia repair. J Am Coll Surg 2011; 212:327-39. [PMID: 21356487 DOI: 10.1016/j.jamcollsurg.2010.12.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2010] [Revised: 12/08/2010] [Accepted: 12/08/2010] [Indexed: 02/07/2023]
Abstract
BACKGROUND The purpose of this study was to compare tissue incorporation and adhesion characteristics of a novel fenestrated versus nonfenestrated crosslinked porcine dermal matrix (CPDM) (Bard CollaMend) in a porcine model of ventral hernia repair. STUDY DESIGN Bilateral abdominal wall defects were created in 24 Yucatan minipigs, resulting in 48 defects, which were allowed to mature for 21 days. Twelve defects were repaired with fenestrated CPDM using a preperitoneal technique, 12 with fenestrated CPDM using an intraperitoneal technique, 12 with nonfenestrated CPDM using a preperitoneal technique, and 12 with nonfenestrated CPDM using an intraperitoneal technique. Half of the animals in the intraperitoneal group were euthanized after 1 month, and the other half after 3 months. Similarly, half of the animals in the preperitoneal group were euthanized after 1 month, and the other half after 6 months. Biomechanical testing and histologic evaluation were performed. RESULTS Intraperitoneal placement of the CPDM products resulted in significantly greater adhesed area compared with preperitoneal placement (p < 0.05). Tissue ingrowth into preperitoneal fenestrated and nonfenestrated CPDM resulted in significantly greater incorporation strengths after 6 months compared with 1 month (p = 0.03 and p < 0.0001). Histologic analysis showed significantly greater cellular infiltration, extracellular matrix deposition, and neovascularization, with less fibrous encapsulation through the center of the fenestrations compared with all other sites evaluated, including nonfenestrated grafts. CONCLUSIONS Histologic findings revealed increased tissue incorporation at fenestration sites compared with nonfenestrated grafts regardless of implant location or time in vivo. However, preperitoneal placement resulted in greater incorporation strength, less adhesed area, and lower adhesion scores compared with intraperitoneal placement for both fenestrated and nonfenestrated CPDM.
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Deeken CR, Melman L, Jenkins ED, Greco SC, Frisella MM, Matthews BD. Histologic and biomechanical evaluation of crosslinked and non-crosslinked biologic meshes in a porcine model of ventral incisional hernia repair. J Am Coll Surg 2011; 212:880-8. [PMID: 21435917 DOI: 10.1016/j.jamcollsurg.2011.01.006] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 12/16/2010] [Accepted: 01/05/2011] [Indexed: 11/16/2022]
Abstract
BACKGROUND The objective of this study was to evaluate the biomechanical characteristics and histologic remodeling of crosslinked (Peri-Guard, Permacol) and non-crosslinked (AlloDerm, Veritas) biologic meshes over a 12 month period using a porcine model of incisional hernia repair. STUDY DESIGN Bilateral incisional hernias were created in 48 Yucatan minipigs and repaired after 21 days using an underlay technique. Samples were harvested at 1, 6, and 12 months and analyzed for biomechanical and histologic properties. The same biomechanical tests were conducted with de novo (time 0) meshes as well as samples of native abdominal wall. Statistical significance (p < 0.05) was determined using 1-way analysis of variance with a Fisher's least significant difference post-test. RESULTS All repair sites demonstrated similar tensile strengths at 1, 6, and 12 months and no significant differences were observed between mesh materials (p > 0.05 in all cases). The strength of the native porcine abdominal wall was not augmented by the presence of the mesh at any of the time points, regardless of de novo tensile strength of the mesh. Histologically, non-crosslinked materials showed earlier cell infiltration (p < 0.01), extracellular matrix deposition (p < 0.02), scaffold degradation (p < 0.05), and neovascularization (p < 0.02) compared with crosslinked materials. However, by 12 months, crosslinked materials showed similar results compared with the non-crosslinked materials for many of the features evaluated. CONCLUSIONS The tensile strengths of sites repaired with biologic mesh were not impacted by very high de novo tensile strength/stiffness or mesh-specific variables such as crosslinking. Although crosslinking distinguishes biologic meshes in the short-term for histologic features, such as cellular infiltration and neovascularization, many differences diminish during longer periods of time. Characteristics other than crosslinking, such as tissue type and processing conditions, are likely responsible for these differences.
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Affiliation(s)
- Corey R Deeken
- Department of Surgery, Section of Minimally Invasive Surgery, Washington University School of Medicine, St Louis, MO, USA.
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Histologic and biomechanical evaluation of a novel macroporous polytetrafluoroethylene knit mesh compared to lightweight and heavyweight polypropylene mesh in a porcine model of ventral incisional hernia repair. Hernia 2011; 15:423-31. [PMID: 21279663 DOI: 10.1007/s10029-011-0787-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 01/09/2011] [Indexed: 12/14/2022]
Abstract
PURPOSE To evaluate the biocompatibility of heavyweight polypropylene (HWPP), lightweight polypropylene (LWPP), and monofilament knit polytetrafluoroethylene (mkPTFE) mesh by comparing biomechanics and histologic response at 1, 3, and 5 months in a porcine model of incisional hernia repair. METHODS Bilateral full-thickness abdominal wall defects measuring 4 cm in length were created in 27 Yucatan minipigs. Twenty-one days after hernia creation, animals underwent bilateral preperitoneal ventral hernia repair with 8 × 10 cm pieces of mesh. Repairs were randomized to Bard(®)Mesh (HWPP, Bard/Davol, http://www.davol.com), ULTRAPRO(®) (LWPP, Ethicon, http://www.ethicon.com), and GORE(®)INFINIT Mesh (mkPTFE, Gore & Associates, http://www.gore.com). Nine animals were sacrificed at each timepoint (1, 3, and 5 months). At harvest, a 3 × 4 cm sample of mesh and incorporated tissue was taken from the center of the implant site and subjected to uniaxial tensile testing at a rate of 0.42 mm/s. The maximum force (N) and tensile strength (N/cm) were measured with a tensiometer, and stiffness (N/mm) was calculated from the slope of the force-versus-displacement curve. Adjacent sections of tissue were stained with hematoxylin and eosin (H&E) and analyzed for inflammation, fibrosis, and tissue ingrowth. Data are reported as mean ± SEM. Statistical significance (P < 0.05) was determined using a two-way ANOVA and Bonferroni post-test. RESULTS No significant difference in maximum force was detected between meshes at any of the time points (P > 0.05 for all comparisons). However, for each mesh type, the maximum strength at 5 months was significantly lower than that at 1 month (P < 0.05). No significant difference in stiffness was detected between the mesh types or between timepoints (P > 0.05 for all comparisons). No significant differences with regard to inflammation, fibrosis, or tissue ingrowth were detected between mesh types at any time point (P > 0.09 for all comparisons). However, over time, inflammation decreased significantly for all mesh types (P < 0.001) and tissue ingrowth reached a slight peak between 1 and 3 months (P = 0.001) but did not significantly change thereafter (P > 0.09). CONCLUSIONS The maximum tensile strength of mesh in the abdominal wall decreased over time for HWPP, LWPP, and mkPTFE mesh materials alike. This trend may actually reflect inability to adequately grip specimens at later time points rather than any mesh-specific trend. Histologically, inflammation decreased with time (P = 0.000), and tissue ingrowth increased (P = 0.019) for all meshes. No specific trends were observed between the polypropylene meshes and the monofilament knit PTFE, suggesting that this novel construction may be a suitable alternative to existing polypropylene meshes.
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