Physico-chemical characteristics of coated silicone textured versus smooth breast implants differentially influence breast-derived fibroblast morphology and behaviour

Effects of substrate topography on the regulation of human fibroblasts and capsule formation via modulating macrophage polarization

The host-material interface is critical in determining the successful integration of medical devices into human tissue. The surface topography can regulate the fibrous capsule formation around implants through macrophage polarization, but the exact mechanism remains unclear. In this study, four types of microgrooves (10 or 50 µm in groove depths and 50 or 200 µm in groove widths) were fabricated on polydimethylsiloxane (PDMS) using lithography. The microgroove surfaces were characterized using the laser scanning confocal microscopy and fourier transform infrared spectroscopy. The effect of surface topography on macrophage phenotypes and conditioned medium (CM) collected from macrophages on human foreskin fibroblast 1 (HFF-1) were investigated. The result revealed that a deeper and narrower microgroove structure means a rougher surface. Macrophages tended to adhere and aggregate on group 50-50 surface (groove depths and widths of 50 µm). THP-1 cell polarized toward both inflammatory M1 and anti-inflammatory M2 macrophages on the surface of each group. Meanwhile, CM from macrophages culture on PDMS differentially up-regulated the proliferation, migration and fibrosis of HFF-1. Among them, the group 50-50 had the strongest promoting effect. In vivo, the inflammatory response and fibrotic capsule around the implants were observed at 1 week and 4 weeks. As time passed, the inflammatory response decreased, while the capsule thickness continued to increase. The rough material surface was more inclined to develop a severe fibrotic encapsulation. In conclusion, this finding further suggested a potential immunomodulatory effect of macrophages in mediating the fibrotic response to implants and facilitated the design of biomaterial interfaces for improving tissue integration.

Advances in surface modifications of the silicone breast implant and impact on its biocompatibility and biointegration

Silicone breast implants are commonly used for cosmetic and oncologic surgical indications owing to their inertness and being nontoxic. However, complications including capsular contracture and anaplastic large cell lymphoma have been associated with certain breast implant surfaces over time. Novel implant surfaces and modifications of existing ones can directly impact cell-surface interactions and enhance biocompatibility and integration. The extent of foreign body response induced by breast implants influence implant success and integration into the body. This review highlights recent advances in breast implant surface technologies including modifications of implant surface topography and chemistry and effects on protein adsorption, and cell adhesion. A comprehensive online literature search was performed for relevant articles using the following keywords silicone breast implants, foreign body response, cell adhesion, protein adsorption, and cell-surface interaction. Properties of silicone breast implants impacting cell-material interactions including surface roughness, wettability, and stiffness, are discussed. Recent studies highlighting both silicone implant surface activation strategies and modifications to enhance biocompatibility in order to prevent capsular contracture formation and development of anaplastic large cell lymphoma are presented. Overall, breast implant surface modifications are being extensively investigated in order to improve implant biocompatibility to cater for increased demand for both cosmetic and oncologic surgeries.

In Vivo and In Vitro Fibroblasts' Behavior and Capsular Formation in Correlation with Smooth and Textured Silicone Surfaces

BACKGROUND

As the most principal complication following breast augmentation with silicone breast implants, capsular contracture is greatly influenced by surface texture. However, there have long been widespread debates on the function of smooth or textured surface implants in reducing capsular contracture.

MATERIALS AND METHODS

Three commercially available silicone breast implants with smooth and textured surfaces were subjected to surface characterization, and in vitro and in vivo assessments were then implemented to investigate the effect of these different surfaces on the biological behaviors of fibroblasts and capsular formation in rat models.

RESULTS

Surface characterization demonstrated that all three samples were hydrophobic with distinct roughness values. Comparing the interactions of fibroblasts or tissues with different surfaces, we observed that as surface roughness increased, the adhesion and cell spreading of fibroblasts, the level of echogenicity, the density of collagen and α-SMA-positive immunoreactivity decreased, while the proliferation of fibroblasts and capsule thickness increased.

CONCLUSIONS

Our findings elucidated that the effect of silicone implant surface texture on fibroblasts' behaviors and capsular formation was associated with variations in surface roughness, and the number of myofibroblasts may have a more significant influence on the process of contracture than capsule thickness in the early stage of capsular formation. These results highlight that targeting myofibroblasts may be wielded in the prevention and treatment strategies of capsular contracture clinically.

LEVEL OF EVIDENCE V

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Surface Texturization of Breast Implants Impacts Extracellular Matrix and Inflammatory Gene Expression in Asymptomatic Capsules

BACKGROUND

Texturing processes have been designed to improve biocompatibility and mechanical anchoring of breast implants. However, a high degree of texturing has been associated with severe abnormalities. In this study, the authors aimed to determine whether implant surface topography could also affect physiology of asymptomatic capsules.

METHODS

The authors collected topographic measurements from 17 different breast implant devices by interferometry and radiographic microtomography. Morphologic structures were analyzed statistically to obtain a robust breast implant surface classification. The authors obtained three topographic categories of textured implants (i.e., "peak and valleys," "open cavities," and "semiopened cavities") based on the cross-sectional aspects. The authors simultaneously collected 31 Baker grade I capsules, sorted them according to the new classification, established their molecular profile, and examined the tissue organization.

RESULTS

Each of the categories showed distinct expression patterns of genes associated with the extracellular matrix (Timp and Mmp members) and inflammatory response (Saa1, Tnsf11, and Il8), despite originating from healthy capsules. In addition, slight variations were observed in the organization of capsular tissues at the histologic level.

CONCLUSIONS

The authors combined a novel surface implant classification system and gene profiling analysis to show that implant surface topography is a bioactive cue that can trigger gene expression changes in surrounding tissue, even in Baker grade I capsules. The authors' new classification system avoids confusion regarding the word "texture," and could be transposed to implant ranges of every manufacturer. This new classification could prove useful in studies on potential links between specific texturizations and the incidence of certain breast-implant associated complications.