A murine model of radiation-induced capsule-tissue reactions around smooth silicone implants

Abstract

As the availability of breast reconstruction using implants is becoming widespread and many implant recipients undergo radiation therapy, there is an increasing interest in understanding the potential complications associated with capsule-tissue interactions in response to irradiation. Accordingly, our medical institution designed an animal experiment to investigate the effects of irradiation on capsular contracture. A total of 40 mice (C57BL6) were divided into four groups according to whether or not they received irradiation and the time from implantation to irradiation. After each mouse received a specially-fabricated, 1.5 cm semi-spherical silicone implant inserted into the area below the panniculus carnosus, half of the mice were irradiated using singe administration of a 10 Gy dose of radiation (6 MeV). Subsequently, data from gross inspection, histological analysis and immunohistochemical analysis were obtained at one and three months postoperatively and analyzed. Changes that occurred near the capsule led to the phenomenon of contracture subsequent to encapsulation. Our findings suggest that the inflammation reaction occurring near the implant becomes aggravated by 'radiation toxicity' and creates an environment conducive to capsular contracture. The present study demonstrated the process by which the complication of capsular contracture may occur during the treatment of human breast cancer via radiotherapy. These findings may serve as the basis for research and development of future treatments of capsular contracture.

Covalently Grafted 2-Methacryloyloxyethyl Phosphorylcholine Networks Inhibit Fibrous Capsule Formation around Silicone Breast Implants in a Porcine Model

“…Small animals such as mice, rats, and rabbits have been frequently employed to analyze biocompatibility issues of small implants. 27,28 However, larger implants such as human silicone breast implants are physically impossible to insert into such small animal models, and the rodent models possess intrinsic limitations for evaluation of skin and subcutaneous tissues in a way that would mimic clinical situations because their epidermal structures are significantly different from the human ones. 29 Therefore, we selected a pig model because it has a well-differentiated epidermal structure similar to human tissues.…”

“…Furthermore, as an initiative to examine the effect of the MPC network surface on capsular formation in a larger animal model, we analyzed the fibrous tissues around the silicone gel-filled breast implants, which are most popularly used in human breast augmentation, in a pig model (Figure D). Small animals such as mice, rats, and rabbits have been frequently employed to analyze biocompatibility issues of small implants. , However, larger implants such as human silicone breast implants are physically impossible to insert into such small animal models, and the rodent models possess intrinsic limitations for evaluation of skin and subcutaneous tissues in a way that would mimic clinical situations because their epidermal structures are significantly different from the human ones . Therefore, we selected a pig model because it has a well-differentiated epidermal structure similar to human tissues. − Since there have been only limited reports for the capsular formation around silicone implants in higher animals, , our study can provide a foundation to demonstrate the process of capsular formation and the effectiveness, validity, and safety of MPC-grafted silicone implants in higher animal models as critical preclinical practices.…”

“Direct-to-Implant, Prepectroal Breast Reconstruction: Geometric Breast Measurements and Changes at 2-Years of Follow-Up”

“…14,15 In subpectoral reconstruction, PMRT causes scarring of the pectoralis major muscle, which culminates in increased pain, implant displacement, and a higher rate of capsular contracture. 16 However, prepectoral implant placement avoids the pectoralis major altogether, and any scarring or fibrotic changes within the muscle will not have an impact on implant placement or preservation of outcomes. Patients undergoing subpectoral breast reconstruction with PMRT have been shown to have a capsular contracture rate three times higher, and more severe (Baker grades 3 to 4), than patients undergoing prepectoral breast reconstruction with PMRT.…”

Strategy for salvaging infected breast implants: lessons from the recovery of seven consecutive patients

“…According to the American Society of Plastic Surgeons, implantbased breast surgery accounted for the largest proportion of breast operations performed in the United States in 2018 [1]. Implant-based breast reconstruction is now considered the first choice for breast reconstruction because of its advantages, which include a short operation time due to the simplicity of the procedure, a rapid postoperative recovery, no donor site, and little scarring; however, its potential complications need to be further elucidated [2,3]. According to Cordeiro et al, the most common early complication of implantation is infection (2.5%); other possible complications include capsular contracture, inaccurate positioning of implants, hematoma, and seroma.…”