COMPARABLE VAGINAL WALLBIOMECHANICAL PROPERTIES FOLLOWING ELECTROSPUN POLYCARBONATE-UREIDOPYRIMIDONE MESH IMPLANTATION AND SIMULATED NATIVE TISSUE REPAIRIN SHEEP
L. HYMPANOVA1, M. G.CUNHA 1, R. RYNKEVIC 2, S. ROMAN 3,M. GALLEGO 4, J. VANGE 5, R. A. WACH 6,G. CALLEWAERT 7, I. URBANKOVA 1, F. VAN DER AA8, S. MACNEIL 3, J. A. DEPREST 9;
1KU Leuven, Leuven, Belgium, 2Faculdade deEngenharia da Univ.e do Porto, Porto, Portugal, 3The KrotoResearch Institute, Univ. of Sheffield, Sheffield, United Kingdom,4Coloplast A/S, Humlebeak, Denmark, 5ColoplastA/S, Humlebaek, Denmark, 6Lodz Univ. of Technology, Lodz,Poland, 7Gynecology and Obstetrics, UZ Leuven, Lubbeek,Belgium, 8Urology, UZ Leuven, Leuven, Belgium, 9UZLeuven, Leuven, Belgium.
Introduction: Novel implants forpelvic organ prolapse repair are introduced to reduce graft relatedcomplications (GRC) without compromising long term outcome.Electrospun hybrid meshes are dynamic scaffolds, can be madebioactive and to have mechanical properties comparable to nativetissue. In earlier work with a novel polymer-based electrospundegradable matrix from a polycaprolactone backbone modified withureidopyrimidone (UPy) motifs were shown not to compromise thecompliance of reinforced abdominal wall muscles in rats. To slow downthe degradation process we used supramolecular polyesterpolycarbonate (PC) modified with UPy motifs.
Objective: Weaimed to compare vaginal compliance following simulated posteriorvaginal repair using native tissue (NT=12) or UPy-PC (n=12) in theovine model for vaginal surgery. Secondary outcome were graft relatedcomplications (GRC). A control abdominal wall implantation was doneas well.
Methods: 24 sheep underwent induction of asimulated vaginal and abdominal wall defect, and were randomized toeither a sutured native tissue repair (NT) or with vaginal mesh(UPy-PC). Sheep were sacrificed at 60 and 180 days (n=6/time point).Primary outcome was passive vaginal biomechanics (ball burst test).Secondary measures were active biomechanical properties(contractility in organ bath), GRC, mesh contraction andsemi-quantitative histo-morphometric evaluation of inflammatoryresponse (PolyMorphoNuclear [PMN] and foreign body giant [FBGC]),vessels on H&E and fibrosis (Masson’s Trichrome).
Results:There were no local complications. Comfort zone stiffness and vaginalwall contractility at 80mM KCl were comparable. Macroscopically theUPy-PC implant looked already degraded at 60d. Microscopically theareas around the UPy-PC matrix were strongly infiltrated with FBGCwithout any difference between the two time points. In the NT repairareas few cells could be detected. Around the UPy-PC there wascollagen deposition that looked well organized. There was also moreneovascularization in the UPy-PC, the largest difference at 180 d.When comparing the vaginal to abdominal UPy-PC implantation site,there were higher cell counts at 60d, yet comparable at 180d.
Conclusions: Vaginal implantation with UPy-PC resorbableelectrospun implants did not cause local complications. Also therewere no differences in passive or active biomechanical properties ofthe distal vaginal wall between the implant and NT repair group.Degradation of the implant is associated with a high numbers of FBGC,suggesting they take part in this process. The graft induces morecollagen organisation and neovascularization. The host response toabdominal implants was different, compatible with earlierobservations that the location of implantation plays a role in thehost response.
Overall,the response to UPy-PC is characterized by high numbers of FBGCand more neovascularization
Foreignbody giant cell, unitless (0-3)
Polymorphonuclearcells, unitless (0-3
TheBadylak score is a semi-quantitative score (0-3) to quantify thehost response, where 0 is no cells/vessels and 3 more than ten.*<0.05