Page 252 - Prevention and Treatment of Incisional Hernia- New Techniques and Materials

Chapter 12
mesh, by producing matrix degrading enzymes and inhibitors of extracellular matrix(5). Van Putten et al.(12) found that the foreign body reaction against collagen discs is delayed in the presence of bacterial cell wall components. Whether the presence of bacterial components also delays the foreign body reaction against synthetic meshes is not known.
Using an in vitro model, we have con rmed mesh-dependent reactions of macrophages in a contaminated environment(6). Previously we studied the in vivo behavior of seven commercially available meshes (1 biological and 6 synthetic meshes) in a contaminated environment in rats and found di erences in mesh infection, adhesions and incorporation of the biomaterial(13). In this experiment polypropylene was used, a mesh often used in patients and also polypropylene based meshes with a hydrophilic collagen-coating, omega 3-fatty acid-coating, and a hyaluronate-carboxymethylcellulose coating, which are described to have a lower complication rate in a clean environment(14). Expanded (microporous) and condensed (macroporous) expanded polytetra uoroethylene (PTFE) meshes were also included. Expanded PTFE has a high infection risk due to the small micropores whereas condensed PTFE is believed to have a good outcome in a contaminated environment due to its macroporous structure(15, 16).
In this study, the cellular immune responses to di erent synthetic meshes in a contaminated environment in vivo are compared in more detail. As macrophages are the key players in the foreign body reaction, the presence of T-cells and mast cells as macrophage attractors and the phenotypes of macrophages with immunohistochemistry are investigated. This knowledge can help the surgeon to choose the best materials to use in an environment with high risk of contamination.
Materials and methods
Contaminated model in vivo
The rat experiment protocol is according to the Animal Research: Reporting In Vivo (ARRIVE) guidelines and was approved by the Ethical Committee on Animal Experimentation of Erasmus University Rotterdam, the Netherlands (EMC 2075-105-10-03). We used samples of an earlier presented study in which in 144 (8 groups, 9 rats per group, two time points) male Wistar rats
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