Short-term behavior of different polymer structure lightweight meshes used to repair abdominal wall defects

Abstract

Background. While lightweight (LW) polypropylene (PP) meshes are been used for hernia repair, new prosthetic meshes also of low-density and with large pores have recently been introduced composed of other polymer materials. This study compares the behavior in the short-term of two macroporous LW prosthetic materials, PP and non-expanded PTFE. Methods. Partial defects were created in the lateral wall of the abdomen in New Zealand White rabbits and then repaired using a LW PP mesh or a new monofile, LW PTFE mesh. At 14 days postimplant, shrinkage and tissue incorporation, gene and protein expression of neocollagens (qRT-PCR/immunofluorescence), macrophage response (immunohistochemistry) and biomechanical strength were determined. Results. Both meshes induced good host tissue ingrowth, yet the macrophage response was significantly greater for the PTFE implants (p<0.05). Collagen 1/3 mRNA expression was greater for the PP mesh but differences lacked significance. Similar patterns of collagen I and III protein expression were observed in the neoformed tissue infiltrating the two meshes. After 14 days of implant, tensile strengths were also similar, while elastic modulus values were higher for the PTFE mesh (p<0.05). Conclusions. In the short term, host collagen deposition and biomechanical performance seemed unaffected by the polymer structure of the implanted mesh. In contrast, the inflammatory response to mesh implant produced at this early time point was more intense for the PTFE.