Surface texturation of breast implant alters extracellular matrix and inflammatory gene expression even in asymptomatic capsule

Introduction: Texturing processes have been designed to improve biocompatibility and mechanical anchoring of breast implants. However, recent findings linked high texturation degree to severe pathologies. Until now, asymptomatic capsules are considered similar irrespective of the type of breast implant surface they face. Objectives : In this paper, we envisaged for the first time that implant surface topography could even affects healthy capsule organization. Materials and methods: We collected topographical measurements from 17 different breast implant devices using interferometry and X-ray Microtomography. Morphological structures were statistically analyzed to raise a robust breast implant surface classification. In parallel, we collected 31 Baker I capsules, sorted them accordingly to the new classification, established their molecular profile and examined related tissue organization on histological sections. A panel of extracellular matrix (Timp1, Timp2, Timp4, Mmp2, Mmp9, Mmp12) and inflammatory related (Saa1, Tnsf11, Il8, Tgfβ1) genes were analysed by performing quantitative PCR (qPCR) experiments on healthy capsules strictly. Results: The new classification resulted in 3 topographical categories of textured implants, defined as "peak and valleys", "open pores" and "semi-closed cavities" based on their cross-section aspect. By comparing capsular tissues from different implants, we found that genes associated with extracellular matrix (Timp and Mmp members) and to the inflammatory response (Saa1, Tnsf11, Il8) exhibit very specific expression patterns, despite originating from healthy capsules. Besides, organization of the capsular tissues was slightly impacted. Conclusions: By combining a novel surface implant classification with gene profiling analysis, we show that surface topography is a bioactive cue that can trigger deep changes in gene expression of the surrounding tissue, even in Baker I capsule. Altogether, our results validate our new classification and suggest that breast implant topography might partly promote the development of breast-implant associated complications.