C-RGD BIOACTIVATION MODERATES THEINFLAMMATORY RESPONSE TO UPY-POLYCARBONATE ELECTROSSPUN MESH IN RAT
M. G. CUNHA 1, L.HYMPANOVA2, S. ZACCARIA 3, R. RYNKEVIC 4,A. VINCKIER 2, R. A. WACH 5, A. OLEJNIK 5,T. MES 6, A. BOSMAN 7, G. CALLEWAERT 8,P. DANKERS 3, J. A. DEPREST 9;
1Developmentand Regeneration, Katholiek Univ.it Leuven, Leuven, Belgium, 2KULeuven, Leuven, Belgium, 3Laboratory of Macromolecular andOrganic Chemistry, Eindhoven Univ. of Technology, Eindhoven,Netherlands, 4Faculdade de Engenharia da Univ.e do Porto,Porto, Portugal, 5Lodz Univ. of Technology, Lodz, Poland,6SupraPolix BV, Eindhoven, Netherlands, 7SupraPolix,Eindhoven, Netherlands, 8Gynecology and Obstetrics, UZLeuven, Lubbeek, Belgium, 9UZ Leuven, Leuven, Belgium.
Introduction: Novel implants forpelvic organ prolapse repair are introduced to improve integrationinto the host and to reduce graft related complications (GRC).Electrospun meshes mimic the structure of extracellular matrix. Theycan be made from degradable polymers and their biomechanicalproperties can be modulated. A polymer-based electrospun mesh withpolycarbonate backbone modified with ureidopyrimidone (UPy) motifshas the advantages that bioactive molecules can be incorporated inthe polymer itself or bound to the mesh surface. Cyclicarginine-glycine-aspartate (cRGD) peptides are one of many possiblemolecules, yet it was selected because it promotes cell adherence(1). Faster adherence of host cells might improve mesh integrationand remodeling.
Objective: We aimed to measure theimmune-modulatory response to cRGD activated UPy-PC mesh in ratmodel, using molecular read outs.
Methods: Twenty-four ratsunderwent surgical creation of an abdominal wall defect. The muscledefect was left unclosed (sham=8) or overlaid either withnon-bioactivated UPy-PC (“pristine” form, n=8) or cRGDbio-activated UPy-PC (cRGD, n=8). Animals were clinically observedfor 14 to 28 d until euthanasia. Primary outcome was local geneexpression quantitated by qPCR. We selected genes representative forthe nature of the inflammatory macrophage response (type 1 [TNF-a,iNOS, IL1β, Il6] or type 2 [IL4, IL10, IL13, TGFB1]),neovascularization (VEGF), extracellular matrix modulation (COL1A1,COL1A2, COL3A1, COL6A1, elastin, alfa-SMA, FGF-2, TIMP-1, MMP-1,MMP9), and adhesion molecules (Endothelin 1, e-Cadherin). Results aredisplayed as a function of gene expression in sham controls.Secondary outcomes were tensiometry of explants at 28 days andMasson’s Trichrome staining to visualize connective tissuedeposition.
Results: There were no mesh exposures. At themolecular level, cRGD modulated a panel of genes representative forthe inflammatory response and connective tissue formation. At 14 dayscRGD explants displayed a lower level of genes associated to amacrophage type 1 dominated response, yet higher for type 2. This wassignificant for iNOS (M1) and TGF beta 1 (M2). At 28 days, cRGDgroups expresses higher amount of both M1 and M2, yet it wassignificant only for TGF beta 1 (Figure 1). It also increasedexpression of genes coding for collagen subtypes. Microscopicallythere was more connective tissue deposition at pristine than aroundcRGD-UPy-PC explants at 28 days (Figure 2) yet there was nomeasurable difference in compliance.
Conclusions: cRGDbioactivation of UPy-PC implants modulates the host response. Wedemonstrated increased expression of markers associated to amacrophage 2 dominated response, as well as increased collagendeposition.
References: 1-Bellis SL. Advantages of RGDpeptides for directing cell association with biomaterials.Biomaterials. 2011;32(18):4205-4210.