Host inflammatory response to polypropylene implants: insights from a quantitative immunohistochemical and birefringence analysis in a rat subcutaneous model

Abstract

Objectives To describe acute and sub acute aspects of histological and immunohistochemical response to PP implant in a rat subcutaneous model based on objective methods.Materials and Methods Thirty rats had a PP mesh subcutaneously implanted and the same dissection on the other side of abdomen but without mesh (sham). The animals were euthanized after 4 and 30 days. Six slides were prepared using the tissue removed: one stained with hematoxylin-eosin (inflammation assessment); one unstained (birefringence evaluation) and four slides for immunohistochemical processing: IL-1 and TNF-α (pro-inflammatory cytokines), MMP-2 (collagen metabolism) and CD-31 (angiogenesis). The area of inflammation, the birefringence index, the area of immunoreactivity and the number of vessels were objectively measured.Results A larger area of inflammatory reaction was observed in PP compared to sham on the 4th and on the 30th day (p=0.0002). After 4 days, PP presented higher TNF (p=0.0001) immunoreactivity than sham and no differences were observed in MMP-2 (p=0.06) and IL-1 (p=0.08). After 30 days, a reduction of IL-1 (p=0.010) and TNF (p=0.016) for PP and of IL-1 (p=0.010) for sham were observed. Moreover, area of MMP-2 immunoreactivity decreased over time for PP group (p=0.018). Birefringence index and vessel counting showed no differences between PP and sham (p=0.27 and p=0.58, respectively).Conclusions The implantation of monofilament and macroporous polypropylene in the subcutaneous of rats resulted in increased inflammatory activity and higher TNF production in the early post implant phase. After 30 days, PP has similar cytokines immunoreactivity, vessel density and extracellular matrix organization.

Long-Lasting Examinations of Surface and Structural Properties of Medical Polypropylene Modified with Silver Nanoparticles

“…However, it was revealed that the mesh erosion was also dependent on the surgeon's experience and the patient age. On the contrary, Prudente et al [16] demonstrated that the implantation of monofilament and macroporous polypropylene in the subcutaneous of rats resulted in the increased inflammatory activity and higher TNF production in the early post implantation phase. After 30 days, PP had the similar cytokines immune reactivity, vessel density and extracellular matrix organization values.…”

Laparoscopy for the Treatment of Congenital Hernia: Use of Surgical Meshes and Mesenchymal Stem Cells in a Clinically Relevant Animal Model

“…Surprisingly, our comparative analyses in 10 different TH1/TH2 cytokines revealed a significant increase in the expression of TNF in the cell group 1 month after implantation. An increase in TNF production has already been linked to the implantation of PP meshes in one study (Prudente et al, 2016). Although a reduction in TNF gene expression in the cell group was expected (Yan et al, 2018) we hypothesized that the short survival and paracrine activity in vivo of stem cells for tissue engineering applications (Dash et al, 2018) was not effective in counteracting the strong inflammatory response induced by the PP mesh.…”

Influence of MMP inhibitor GM6001 loading of fibre coated polypropylene meshes on wound healing: Implications for hernia repair

“…could not find differences in MMP-2 secretion between normal and hernia-derived fibroblasts incubated with synthetic meshes, 28 increased MMP-2 tissue levels were found around meshes implanted for pelvic organ prolapse 66 as well as around subcutaneous PP implants. 67 Obviously, augmented MMP-2 in connective tissues confers laxity and instability of tissues leading to hernia formation, 68 prolapse 69 and aneurysms. 70 Here, we observed an initial increase of MMP-2 during the inflammatory phase of wound healing until day 14 followed by decrease over time.…”