Arquitectura morfo-funcional de la válvula íleo-cecal : sistemas integradores en el feto y en el recién nacido

Fac. de MedicinaTRUEProQuestpu

Arquitectura morfo-funcional de la válvula íleo-cecal : sistemas integradores en el feto y en el recién nacido

Fac. de MedicinaTRUEProQuestpu

Effects of collagen prosthesis crosslinking on long-term tissue regeneration following the repair of an abdominal wall defect

22 p.Collagen prostheses used to repair abdominal wall defects, depending on their pretreatment (noncross-linked vs. cross-linked), besides repair may also achieve tissue regeneration. We assessed the host tissue incorporation of different bioprostheses using a new tool that combines immunofluorescence confocal microscopy with differential interference contrast images, making it possible to distinguish newly formed collagen. Partial hernial defects in the abdominal wall of rabbits were repaired using cross-linked/noncross-linked bioprostheses. Expanded polytetrafluoroethylene (ePTFE) was used as control. After 14/30/90/180 days of implant, specimens were taken for microscopy, immunohistochemistry, and quantitative-reverse transcription-polymerase chain reaction to determine host tissue ingrowth and collagen I/III protein and 1a1/3a1 gene expression. Shrinkage and stress resistance were also examined. At 14 days, crosslinked prostheses had suffered significantly lessshrinkage than ePTFE or noncross-linked prostheses. Significantly higher shrinkage was recorded for ePTFE in the longer term. Microscopy revealed encapsulation of ePTFE by neoformed tissue, while the bioprostheses became gradually infiltrated byhost tissue. Noncross-linked prosthesis showed better tissue ingrowth, more intense inflammatory reaction and more rapid degradation than the cross-linked prostheses. At 14 days, cross-linked prostheses induced up-regulated collagen 1a1 and 3a1 geneexpression, while noncross-linked only showed increased collagen III protein expression at 90 days postimplant. At 6 months, the tensile strengths of cross-linked prostheses were significantly greater compared with ePTFE. Our findings demonstrate that despite the cross-linked collagen prostheses promoting lesstissue ingrowth than the noncross-linked meshes, they became gradually replaced by good quality host tissue and were less rapidly degraded, leading to improved stress resistance in the long term.Fundación Mutua MadrileñaMinisterio de Ciencia y Tecnologí

Polymer hernia repair materials: adapting to patient needs and surgical techniques

"Publicación presentada para convocatoria 2023 Proyectos Generación de Conocimiento"Biomaterials and their applications are perhaps among the most dynamic areas of research within the field of biomedicine. Any advance in this topic translates to an improved quality of life for recipient patients. One application of a biomaterial is the repair of an abdominal wall defect whether congenital or acquired. In the great majority of cases requiring surgery, the defect takes the form of a hernia. Over the past few years, biomaterials designed with this purpose in mind have been gradually evolving in parallel with new developments in the different surgical techniques. In consequence, the classic polymer prosthetic materials have been the starting point for structural modifications or new prototypes that have always strived to ccommodate patients? needs. This evolving process has pursued both improvements in the wound repair process depending on the implant interface in the host and in the material?s mechanical properties at the repair site. This last factor is important considering that this site?the abdominal wall?is a dynamic structure subjected to considerable mechanical demands. This review aims to provide a narrative overview of the different biomaterials that have been gradually introduced over the years, long with their modifications as new surgical techniques have unfolded

Efficacy of antimicrobial agents delivered to hernia meshes using an adaptable thermo-responsive hyaluronic acid-based coating

19 p.Purpose Mesh-related infection is a critical outcome for patients with hernia defect stabilized with synthetic or biological meshes. Even though bioactive meshes loaded with antibiotics or antiseptics are slowly emerging in the market, the available solutions still lack versatility. Here, we proposed a polymer solution, i.e., hyaluronic acid-poly(N-isopropylacrylamide) (HApN), which forms a hydrogel to be used as coating for meshes only when it reaches body temperature. Methods We assessed how the gelation of HApN was influenced by the incorporation of different antibiotic and antiseptic formulations, and how this gel can be used to coat several mesh types. The impact of the coating on the elastic behavior of a macroporous mesh was tested under cyclic elongation condition. Finally, we selected two different coating formulations, one based on antibiotics (gentamicin + rifampicin) and one based on antiseptic (chlorhexidine) and tested in vitro their antimicrobial efficacies. Results HApN can be used as carrier for different antimicrobial agents, without having a strong influence on its gelation behavior. Porous or dense meshes can be coated with this polymer, even though the stability was not optimal on macroporous meshes such as Optilene when pores are too large. HApN loaded with drugs inhibited in vitro the growth of several Gram-positive and Gram-negative bacteria. Conclusion Compared to the available technologies developed to endow meshes with antibacterial activity, the proposed HApN offers further versatility with potential to prevent mesh-related infection in hernioplasty.European Hernia SocietyMinisterio de Ciencia, Innovación y Universidade

The long-term behavior of lightweight and heavyweight meshes used to repair abdominal wall defects is determined by the host tissue repair process provoked by the mesh

17 p.Background. Although heavyweight (HW) or lightweight (LW) polypropylene (PP) meshes are widely used for hernia repair, other alternatives have recently appeared. They have the same large-pore structure yet are composed of polytetrafluoroethylene (PTFE). This study compares the long-term (3 and 6 months) behavior of meshes of different pore size (HW compared with LW) and composition (PP compared with PTFE). Methods. Partial defects were created in the lateral wall of the abdomen in New Zealand White rabbits and then repaired by the use of a HW or LW PP mesh or a new monofilament, large-pore PTFE mesh (Infinit). At 90 and 180 days after implantation, tissue incorporation, gene and protein expression of neocollagens (reverse transcription-polymerase chain reaction/immunofluorescence), macrophage response (immunohistochemistry), and biomechanical strength were determined. Shrinkage was measured at 90 days. Results. All three meshes induced good host tissue ingrowth, yet the macrophage response was significantly greater in the PTFE implants (P .05). Conclusion. Host collagen deposition is mesh pore size dependent whereas the macrophage response induced is composition dependent with a greater response shown by PTFE. In the long term, macroporous meshes show comparable biomechanical behavior regardless of their pore size or composition. (Surgery 2012;152:886-95.

Experimental study on the use of a chlorhexidine-loaded carboxymethylcellulose gel as antibacterial coating for hernia repair meshes

21 p.Purpose: Biomaterials with an antimicrobial coating could avoid mesh-associated infection following hernia repair. This study assesses the use of a chlorhexidine-loaded carboxymethylcellulose gel in a model of Staphylococcus aureus mesh infection. Methods: A 1% carboxymethylcellulose gel containing 0.05% chlorhexidine was prepared and tested in vitro and in vivo. The in vitro tests were antibacterial activity (S. aureus; agar diffusion test) and gel cytotoxicity compared to aqueous 0.05% chlorhexidine (fibroblasts; alamarBlue). For the in vivo study, partial abdominal wall defects (5 × 2 cm) were created in New Zealand white rabbits (n = 15) and inoculated with 0.25 mL of S. aureus ( 106 CFU/mL). Defects were repaired with a lightweight polypropylene mesh (Optilene) without coating (n = 3) or coated with a carboxymethylcellulose gel (n = 6) or chlorhexidine-loaded carboxymethylcellulose gel (n = 6). Fourteen days after surgery, bacterial adhesion to the implant (sonication, immunohistochemistry), host tissue incorporation (light microscopy) and macrophage reaction (immunohistochemistry) were examined. Results: Carboxymethylcellulose significantly reduced the toxicity of chlorhexidine (p < 0.001) without limiting its antibacterial activity. While control and gel-coated implants were intensely contaminated, the chlorhexidine-gel-coated meses showed a bacteria-free surface, and only one specimen showed infection signs. The macrophage reaction in this last group was reduced compared to the control (p < 0.05) and gel groups. Conclusions: When incorporated in the carboxymethylcellulose gel, chlorhexidine showed reduced toxicity yet maintained its bactericidal effect at the surgery site. Our findings suggest that this antibacterial gel-coated polypropylene meshes for hernia repair prevent bacterial adhesion to the mesh surface and have no detrimental effects on wound repair.Ministerio de Ciencia, Innovación y Universidade

New insights into the application of 3D-printing technology in hernia repair.

"Publicación presentada para sexenios"Abdominal hernia repair using prosthetic materials is among the surgical interventions most widely performed worldwide. These materials, or meshes, are implanted to close the hernial defect, reinforcing the abdominal muscles and reestablishing mechanical functionality of the wall. Meshes for hernia repair are made of synthetic or biological materials exhibiting multiple shapes and configurations. Despite the myriad of devices currently marketed, the search for the ideal mesh continues as, thus far, no device offers optimal tissue repair and restored mechanical performance while minimizing postoperative complications. Additive manufacturing, or 3D-printing, has great potential for biomedical applications. Over the years, different biomaterials with advanced features have been successfully manufactured via 3D-printing for the repair of hard and soft tissues. This technological improvement is of high clinical relevance and paves the way to produce next-generation devices tailored to suit each individual patient. This review focuses on the state of the art and applications of 3D-printing technology for the manufacture of synthetic meshes. We highlight the latest approaches aimed at developing improved bioactive materials (e.g., optimizing antibacterial performance, drug release, or device opacity for contrast imaging). Challenges, limitations, and future perspectives are discussed, offering a comprehensive scenario for the applicability of 3D-printing in hernia repair.Financial support from the CIBER-BB

Mesh fixation using a cyanoacrylate applied as a spray improves abdominal wall tissue repair

19 p.Background: Tissue adhesives are a feasible option to fix a hernia repair mesh, avoiding tissue trauma of suture fixation. Classically, they are applied in the form of a drop, although novel applications such as spray are emerging. This study compares the use of a new experimental cyanoacrylate (n-butyl) in the form of a spray or drops. Materials and methods: Three study groups of New Zealand White rabbits were established (n ? 6 each) according to the method used to fix a 5 3 cm polypropylene mesh in a partial abdominal wall defect model: control group (polypropylene stitches), adhesive drops group, and adhesive spray group. Morphological, immunohistochemical, and biomechanical strength studies were performed at 14 d postimplant. Collagen 1/3 gene ratio was determined by quantitative reverse transcription polymerase chain reaction. Results: In the drops group, the adhesive obstructed the mesh pores and prevented tissue infiltration at the points of application. When the adhesive was applied as a spray, although more numerous, adhesive deposits were smaller and allowed for better host tissue infiltration into the mesh. The inflammatory response was similar in the adhesive groups and more intense than in the control group. Collagen 1/3 mRNA ratio was significantly higher in the spray than the control group. The mechanical resistance of the meshes was similar in all three groups. * Corresponding author. Department of Surgery, Medical and Social Sciences. Faculty of Medicine and Health Sciences, University of Alcala, Ctra. Madrid-Barcelona, Km 33,600, Alcala de Henares, 28871 Madrid, Spain. Tel.: þ34 91 8854540; fax: þ34 91 8854885. E-mail address: [email protected] (J.M. Bellon). 1 These authors contributed equally to this work. 0022-4804/$ e see front matter ª 2019 Elsevier Inc. All rights reserved. https://doi.org/10.1016/j.jss.2019.08.020 Conclusions: The application of the cyanoacrylate adhesive in the form of spray to fix polypropylene meshes in an animal model had a similar inflammatory response compared with droplet application. Neither application impacted the mechanical strength of the repaired area. An increased in collagen 1/3 ratio was found with cyanoacrylate spray compared with suture, and future studies should focus on this pathway.Ministerio de Economía y Competitivida

Repair of abdominal wall defects with biodegradable laminar prostheses polymeric or biological?

11 p.Introduction: Biological and synthetic laminar absorbable prostheses are available for the repair of hernia defects in the abdominal wall. They share the important feature of being gradually degraded in the host, resulting in place the formation of a neotissue. This study was designed to assess the host tissue?s incorporation of collagen bioprostheses and a synthetic absorbable prosthesis. Methods: Partial defects were created in the abdominal walls of 72 New Zealand rabbits and repaired using collagen bioprostheses TutomeshH and StratticeH or a synthetic prosthesis Bio-AH. Specimens were collected for light microscopy, collagens gene and protein expression, macrophage response and biomechanical resistance at 14, 30, 90 and 180 days postimplantation. Results: TutomeshH and Bio-AH were gradually infiltrated by the host tissue and almost completely degraded by 180 days post-implantation. In contrast, StratticeH exhibited material encapsulation, no prosthetic degradation and low cell infiltration at earlier timepoints, whereas at later study time, collagen deposition could be observed within the mesh. In the short term, Bio-AH exhibited higher level of collagen 1 and 3 mRNA expression compared with the two other biological prostheses, which exhibited two peaks of higher expression at 14 and 90 days. The expression of collagen III was homogeneous throughout the study and collagen I deposition was more evident in StratticeH. Macrophage response decreased over time in biomeshes. However, in the synthetic mesh remained high and homogeneous until 90 days. The biomechanical analysis demonstrated the progressively increasing tensile strength of all biomaterials. Conclusions: The tissue infiltration of laminar absorbable prostheses is affected by the structure and composition of the mesh. The synthetic prosthesis exhibited a distinct pattern of tissue incorporation and a greater macrophage response than did the biological prostheses. Of all of the laminar, absorbable biomaterials that were tested in this study, StratticeH demonstrated the optimal levels of integration and degradation.Fundación Médica Mutua MadrileñaMinisterio de Ciencia y Tecnologí