Impact of the structure of polypropylene meshes in local tissue reaction: in vivo stereological study

Abstract

Polypropylene slings are monofilament and multifilament meshes. Their features can impact clinical outcomes. We analyzed tissue reaction, inflammation, and the density of collagen fibers elicited by polypropylene meshes in the subcutaneous tissue of female rats. Thirty female Wistar rats underwent the implantation of 8x4-mm polypropylene meshes (two monofilamentar and two multifilamentar). The rats were killed at 7, 60, and 120 days after implant. Stereology was used to analyze the collagen fiber density. Acute inflammation was more intense in the early post-implant period (p=0.006), except for intravaginal slingplasty (p=0.342). Lymphoplasmocytic reaction was more intense in multifilament samples, even after 60 days (p<0.001) and 120 days (p=0.001). The stereological analysis showed significant differences between mono- and multifilament meshes, considering that monofilament meshes induced more collagen deposition and a greater density of collagen fibers (p<0.001). Multifilament meshes produced a more granulomatous reaction. The collagen fiber density was greater in monofilament meshes, which induced more favorable biocompatibility assessed objectively.

Primary fixation of mini slings: a comparative biomechanical study in vivo

“…Implants made of this have shown experimentally better tissue integration when compared to other synthetic materials. Other materials and coatings were studied for clinical use but have not demonstrated superiority to the polypropylene type I (28).…”

Gluteo-vaginal fistula: a long-term complication of posterior intravaginal slingplasty

“…The type III polypropylene macroporous mesh with multifilaments used in our case and many other PIVS has small interstices and pore size (<10 um) which limits macrophage and fibroblast infiltration, collagen deposition and neovascularisation resulting in poor tissue integration9 and a subsequent granulomatous reaction 10…”

A new material to prevent urethral damage after implantation of artificial devices: an experimental study

“…This was different from that observed in the groups, which received silicon alone, where there was intense collagen deposition, at different periods of measurement. It is well known that the biocompatibility of a material is validated by the degree of inflammatory reaction of vascularized tissue at the implant area (23). …”

“…The process of biocompatibility is induced through the recruitment of inflammatory cells in the implant area, which in turn contributes to the onset of neovascularization and consequent nutritional intake, necessary for the survival and transformation of the implanted matrix (23-25). It is worth to emphasize that in the inflammatory process itself cellularity is gradually replaced by fibroblasts and, therefore, collagen deposition, serves as a platform basis for the appearance of a new tissue structure (24).…”