Influence of curing agent on fibrosis around silicone implants

Abstract

Severe capsular contracture around silicone expander breast implants leading to pain and failure is a major clinical problem. Even though earlier studies have implicated the immunogenicity of silicone, the role of physical and chemical properties of the silicone material in excessive collagen deposition and fibrosis has been less addressed. The present study investigates whether there is any correlation between the type of curing systems i.e. addition and free radical curing and the fibrosis around silicone elastomer. The experiment carried out uses commercially available silicone ventriculo-peritoneal shunt material elastomer cured by platinum and the results are compared with results obtained in a similar study carried out by the authors using commercially available silicone tissue expander material cured by peroxide. Ultra-high molecular weight poly-ethylene (UHMWPE), the standard reference for biocompatibility evaluation, was used as the control material. The materials were implanted in rat skeletal muscle for 30 and 90 days. Inflammatory cells, myofibroblasts, cytokines, and collagen deposition at the material-tissue interface were identified by haematoxylin-eosin and Masson's Trichrome stains and semi-quantitated based on immunohistochemical studies. Results indicate that even though the cellular response in the initial phase of wound healing was similar in both platinum and peroxide-cured materials, the collagen deposition in the proliferative phase was more around peroxide-cured material in comparison to the platinum-cured silicone elastomer. There is a need to look into the molecular mechanisms of this interaction and the possibility of using curing systems other than free radical peroxide in the manufacture of silicone elastomer expanders for breast prosthesis.

Foreign Body Response to Silicone in Cochlear Implant Electrodes in the Human

“…Reduction of the foreign body response to implanted electrodes may be achieved by alterations in surface chemistry of implanted biomaterials, 33,34,35,36 or by changing the surface topography of the implanted electrode array, 37 or the use of biomimetic silicone surfaces. 38 It also remains to be seen what kind of response is initiated with implantation through the RW membrane versus a drilled cochleostomy site.…”

Analysis of Silicones Released from Household Items and Baby Articles by Direct Analysis in Real Time-Mass Spectrometry

“…However, when studied, the long-term exposure of humans to silicones was found to induce adverse health effects. For example, adverse health effects of silicones released under physiological conditions from breast implants are discussed in the context of breast cancer [1], fibrosis [2], autoimmunity [3], and inflammatory processes [4]. Nonetheless, the use of PDMS and related silicones stills seems to increase and silicone has even been suggested as a potent absorbing material for 3-alkyl-methoxypyrazine responsible for undesirable aromas in wine [5].…”

Biomolecules that impact phenotypic transitions in fibroblasts and macrophages

“…Biosensors are also rendered useless because analytes are unable to diffuse to and be detected by the sensor [59]. Additionally, long-term failure of implanted constructs, such as breast implants, often results from continued fibrous capsule formation and matrix remodeling [101,102]. Material properties such as chemistry, scaffold processing, pore size, and topography have effects on the thickness and character of the fibrous capsule that is the common end result to the FBR.…”

“…Material properties such as chemistry, scaffold processing, pore size, and topography have effects on the thickness and character of the fibrous capsule that is the common end result to the FBR. [101,104].…”

“…The biocompatibility of these materials is defined by how well they interface with the adjacent tissue. Due to the innate immune response, known as the FBR, that is mounted against these devices and scaffolds, excessive healing, also known as constrictive fibrosis, can occur[101]. Often, this excessive healing process results in fibrotic encapsulation and isolation of the implant[14].…”