The surface topography of silicone breast implants mediates the foreign body response in mice, rabbits, and humans

Sponsored by: Thermo Fisher Scientific

Speaker

Dr. Joshua C. Doloff

Assistant Professor, Biomedical Engineering and Materials Science Engineering
BIOGRAPHY

Event Date & Time

Date: September 8, 2021

Time: 9:00am (PDT), 12:00pm (EDT)

Abstract

Implanted biomedical devices comprise a major component of modern medicine and are essential for many clinical applications ranging from tissue repair and reconstruction, electrical pacing and stimulation, controlled release, glucose sensing, and cell transplantation. Silicone, widely used in chronic implants for breast reconstruction and augmentation, has generally been perceived as safe. However, host immune system–mediated foreign body response (FBR) has caused a significant impediment to therapeutic performance and lifespan, resulting in fibrotic scar tissue and implant distortion through capsular contracture. Originally thought to help with placement and reduction of FBR, textured breast implants have unfortunately been associated with immune-related complications, including malignancies. Therefore, to better understand the contribution of implant surface in altering host response, miniaturized or full-scale clinically approved breast implants with varied surface topographies (average roughness ranging between 0–90 μm, with ISO designations of smooth, microtextured, or macrotextured) were placed in the mammary fat pads of mice and rabbits, respectively, and examined for up to one year. Of note, surface topography was found to mediate host fibrosis and immune responses across all models tested. We also show that surface topography of implant differentially alters host implant response in capsules isolated during revision surgeries in human patients. Regarding immune mechanism, miniaturized implants with an average roughness of 4 μm largely suppress FBR and fibrosis (though not in T cell–deficient mice), and surrounding tissue displayed higher levels of immunosuppressive FOXP3⁺ regulatory T cells as well as an overall reduced state of inflammation. Collectively, our findings may have profound implications for implant choice by patients and clinicians alike, and suggest that, amongst the topographies investigated, implants with an average roughness of 4 μm provoke the least amount of inflammation and foreign body response.

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