Current Approaches Including Novel Nano/Microtechniques to Reduce Silicone Implant-Induced Contracture with Adverse Immune Responses

Impact on capsule formation for three different types of implant surface tomography

Although capsular contracture remains one of the major problems following silicone breast implantation, the associated mechanism has yet to be determined. This study thus aimed to investigate capsule formation and capsular contracture using three types of implants with different surface topographies in vivo. Three types of implants (i.e., smooth, macrotexture, and nanotexture) with different surface topographies were inserted in a total of 48 Wistar rats. After 4 and 12 weeks, the samples were analyzed via histological, immunohistochemical, and Western blot examination. To identify implant movement, the degree to which implant position changed was measured. And the surface topography was characterized using scanning electron microscopy. Hematoxylin–eosin staining showed that the nanotexture type implant promoted significant decreases in capsule thickness at 12 weeks (P < 0.05), while Masson trichrome staining showed decreased collagen fiber density with the same implant type. Immunohistochemical and Western blot examination revealed reduced fibrosis markers (myofibroblast, and transforming growth factor beta-1) in the nanotexture surface implant. Meanwhile, implant location evaluation found that the nanotexture and smooth surface implants had significantly increased movement (P < 0.05). The nanotexture surface implant had been found to reduce capsule formation given that it minimizes the effects of factors related to foreign body reaction.

Asiaticoside Combined With Carbon Ion Implantation to Improve the Biocompatibility of Silicone Rubber and to Reduce the Risk of Capsule Contracture

Capsular contracture caused by silicone rubber is a critical issue in plastic surgery that urgently needs to be solved. Studies have shown that carbon ion implant in silicone rubber (carbon silicone rubber, C-SR) can significantly improve the capsular structure, but the effect of this improvement only appear 2months or later. In this study, asiaticoside combined with carbon silicone rubber was used to explore the changes in the capsule to provide a reference for the treatment of capsule contracture. Human fibroblasts (HFF-1) were used for in vitro experiments. The combined effect of asiaticoside and carbon silicone rubber on cell proliferation was determined by the CCK8 method, cell migration changes were measured by Transwell assays, cell cycle changes were measured by flow cytometry, and the expression levels of fibroblast transformation markers (vimentin and α-SMA), collagen (Col-1A1) and TGF-β/Smad signaling pathway-related proteins (TGF-β1, TβRI, TβRII and Smad2/3) were detected by immunofluorescence. In vivo experiments were carried out by subcutaneous implantation of the material in SD rats, and asiaticoside was oral administered simultaneously. WB and ELISA were used to detect changes in the expression of TGF-β/Smad signaling pathway-related proteins. TGF-β/Smad signaling pathway proteins were then detected and confirmed by HE, Masson and immunohistochemical staining. The results shown that asiaticoside combined with carbon ion implantation inhibited the viability, proliferation and migration of fibroblasts on silicone rubber. In vitro immunofluorescence showed that the secretion levels of α-SMA and Col-1A1 were significantly decreased, the transformation of fibroblasts into myofibroblasts was weakened, and the TGF-β/Smad signaling pathway was inhibited. In vivo experimental results showed that asiaticoside combined with carbon silicone rubber inhibited TGF-β1 secretion and inhibited the TGF-β/Smad signaling pathway, reducing the thickness of the capsule and collagen deposition. These results imply that carbon silicone rubber combined with asiaticoside can regulate the viability, proliferation and migration of fibroblasts by inhibiting the TGF-β/Smad signaling pathway and reduce capsule thickness and collagen deposition, which greatly reduces the incidence of capsule contracture.

Assessment of human adipose-derived stem cell on surface-modified silicone implant to reduce capsular contracture formation

Medical devices made from poly(dimethylsiloxane) (PDMS)-based silicone implants have been broadly used owing to their inert properties, biocompatibility, and low toxicity. However, long-term implantation is usually associated with complications, such as capsular contracture due to excessive local inflammatory response, subsequently requiring implant removal. Therefore, modification of the silicone surface to reduce a risk of capsular contracture has attracted increasing attention. Human adipose-derived stem cells (hASCs) are known to provide potentially therapeutic applications for tissue engineering, regenerative medicine, and reconstructive surgery. Herein, hASCs coating on a PDMS (hASC-PDMS) or itaconic acid (IA)-conjugated PDMS (hASC-IA-PDMS) surface is examined to determine its biocompatibility for reducing capsular contracture on the PDMS surface. In vitro cell cytotoxicity evaluation showed that hASCs on IA-PDMS exhibit higher cell viability than hASCs on PDMS. A lower release of proinflammatory cytokines is observed in hASC-PDMS and hASC-IA-PDMS compared to the cells on plate. Multiple factors, including in vivo mRNA expression levels of cytokines related to fibrosis; number of inflammatory cells; number of macrophages and myofibroblasts; capsule thickness; and collagen density following implantation in rats for 60 days, indicate that incorporated coating hASCs on PDMSs most effectively reduces capsular contracture. This study demonstrates the potential of hASCs coating for the modification of PDMS surfaces in enhancing surface biocompatibility for reducing capsular contracture of PDMS-based medical devices.

Peri-prosthetic Fat Grafting Decreases Collagen Content, Density, and Fiber Alignment of Implant Capsules

Background:

Lower capsular contracture rates have been observed with peri-prosthetic fat grafting. We investigated the effect of fat grafting on capsular characteristics and peri-prosthetic collagen density, content, and fiber alignment.

Methods:

Forty miniature tissue expanders were placed on the backs of 20 rats. After four weeks, both inguinal fat pads were harvested, homogenized, and injected into peri-prosthetic tissue of the right tissue expander (fat graft) while the left served as control. The animals were killed at three (10 rats) and 12 weeks (10 rats), and full thickness peri-prosthetic samples were histologically processed for morphology (H&E) and collagen type and content (picrosirius red).

Results:

An 8.1% increase in adipose peri-prosthetic thickness was associated with a 10% decrease in collagen content at any time point (P = 0.004). Fat-grafted capsules displayed a 59% reduction in % total collagen when compared with controls (P < 0.001). There were no differences in capsular thickness. Fat-grafted samples were 54 times more likely to have a higher inflammation score and 69 times more likely to have a lower capsular density score than their nongrafted counterparts (P < 0.001 and P = 0.001, respectively). The extent of inflammation decreased over time in all samples (P = 0.002). Additionally, fat-grafted samples were 67 times more likely to have a lower fiber alignment score than the controls (P < 0.001).

Conclusions:

Enhancement of peri-prosthetic tissue with fat grafting decreases collagen content, density, and fiber alignment of implant capsules. These findings support clinical application of fat grafting in prosthetic breast surgery to potentially decrease capsular contracture.

A Case Report of Capsular Contracture Immediately Following COVID-19 Vaccination

Capsular contracture is fundamentally an immunological/inflammatory response to the implant, treating it as a foreign body in need of exclusion from the immune system. The capsule surrounding the implant is populated by a rich variety of immunologically active cells such as macrophages, T lymphocytes, and myofibroblasts. Vaccination in general and the COVID-19 vaccine in particular result in specific and nonspecific activation of the immune system, including those immune cells in proximity to the implant. This phenomenon has been previously demonstrated in delayed inflammatory reactions to previously implanted hyaluronic acid fillers following COVID-19 vaccination. This report is what is believed to be the first case of the rapid development of severe ipsilateral capsular contracture in the immediate aftermath of the second dose of the BNT162b2 (Pfizer) vaccine.

Silicone Breast Implant Coated with Triamcinolone Inhibited Breast-Implant-Induced Fibrosis in a Porcine Model

Cosmetic silicone implants for breast reconstruction often lead to medical complications, such as abnormally excessive fibrosis driven by foreign body granulomatous inflammation. The purpose of this study was to develop a silicone breast implant capable of local and controlled release of a glucocorticoid drug triamcinolone acetonide (TA) for the prevention of silicone-breast-implant-induced fibrosis in a Yorkshire pig model (in vivo). Implants were dip-coated in a TA solution to load 1.85 μg/cm² of TA in the implant shell, which could release the drug in a sustained manner for over 50 days. Immunohistochemical analysis for 12 weeks showed a decline in tumor necrosis factor-α expression, capsule thickness, and collagen density by 82.2%, 55.2%, and 32.3%, respectively. Furthermore, the counts of fibroblasts, macrophages, and myofibroblasts in the TA-coated implants were drastically reduced by 57.78%, 48.8%, and 64.02%, respectively. The TA-coated implants also lowered the expression of vimentin and α-smooth muscle actin proteins, the major profibrotic fibroblast and myofibroblast markers, respectively. Our findings suggest that TA-coated silicone breast implants can be a promising strategy for safely preventing fibrosis around the implants.

[Impact of breast dimension in one-stage augmentation mastopexies on implant selection: review of 103 consecutive breast augmentations with nanotextured silicone implants]

INTRODUCTION

According to current studies, one-stage augmentation mastopexy (AM) is associated with only minor complications and a lower reoperation rate compared with a staged procedure. In AM, breast dimension can differ notably compared with those cases without simultaneous mastopexy. However, these differences have only been insufficiently investigated. This study aims to quantify the differences and then evaluate the effect of breast dimension on implant selection. In addition, it evaluates the influence of mastopexy on the outcome of augmentation mammoplasties with round nanotextured silicone gel implants.

PATIENTS AND METHODS

Over a two-year period, all patients with primary augmentation mammoplasties using nanotextured implants were included in the study. Patients' demographic data, breast measurements, specifications of the implants placed, and complications in the breast augmentation group without mastopexy were compared with those of the group with AM. The satisfaction of patients and surgeons was documented using Likert scales.

RESULTS

A total of 206 breast augmentations were performed in n = 103 patients. The mean follow-up was 24.0 ± 4.3 months. Compared with augmentations without an indication for simultaneous mastopexy, the AM group had wider breast bases and larger preoperative cup sizes; p < 0.001. As a result, implants selected for AM had greater diameters and lower volumes (p < 0.05) and were associated with smaller projections; p < 0.001. The total revision rates after augmentations without (n = 51) and with combined mastopexy (n = 52) were 5.9 % and 19.2 % (p < 0.05), respectively. AM increased tissue-related revisions from 2.0 % to 13.4 % (p < 0.05) without having an impact on implant-related revisions (3.9 % vs. 5.8 %, p = 0.663). The overall incidence of capsular contracture was 1.9 %. Satisfaction levels were approximately equal in both groups.

CONCLUSION

In comparison to augmentations without mastopexy, wider breast bases and larger breast volumes before surgery lead to the selection of significantly different implant dimensions in AM. Nanotextured silicone implants are associated with low complication rates, while an increased risk for tissue-related revisions of the combined procedure remains. Further studies are necessary in order to evaluate possible advantages and disadvantages over established implants.

Short-term treatment outcomes and safety of two representative brands of the fifth-generation silicone gel-filled breast implants in Korea

It is allegedly reported that the BellaGel^® SmoothFine (HansBiomed Co. Ltd., Seoul, Korea) and Motiva Ergonomix^TM (Establishment Labs Holdings Inc., Alajuela, Costa Rica) are representative brands of a microtextured breast implant in Korea. We compared short-term safety outcomes between them. We evaluated the patients who received breast augmentation using the BellaGel^® SmoothFine (n = 264) or the Motiva Ergonomix™ (n = 76) for aesthetic purposes and those with available medical records. They were followed up during a mean period of 122.11 ± 95.37 (4-477) and 126.80 ± 116.29 (13-534) days in the corresponding order. Early seroma occurred at an incidence of 1.89 and 5.26% following breast augmentation using the BellaGel^® SmoothFine and the Motiva Ergonomix^TM, respectively. This difference reached statistical significance (p < 0.05). Of note, CC occurred at an incidence of 2.27 and 0.00% in the corresponding order. Cumulative incidences of postoperative complications depending on the type of breast implants showed no significant difference; statistical significance was analyzed using the log-rank test (χ² = 1.71, df = 1, p = 0.19). Cumulative survival of the breast implant is shown in Table 3; the Motiva Ergonomix™ showed a longer survival as compared with the BellaGel^® SmoothFine (130.13 ± 13.70 vs. 120.45 ± 5.76 days). In conclusion, we describe short-term treatment outcomes and safety of an implant-based breast augmentation using two representative brands of the fifth-generation silicone gel-filled breast implants in Korean women.

Biological and genetic landscape of breast implant-associated anaplastic large cell lymphoma (BIA-ALCL)

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is an uncommon form of non-Hodgkin lymphoma (cancer of the immune system) that can develop around breast implants. Breast implants are among the most commonly used medical devices for cosmetic or reconstructive purposes. In the past few years, the number of women with breast implants diagnosed with anaplastic large cell lymphoma (ALCL) has increased, and several studies have suggested a direct association between breast implants and an increased risk of this disease. Although it has been hypothesized that chronic stimulation of the immune system caused by implant materials and biofilms as well as a possible genetic predisposition play an important role in this disease, the cellular and molecular causes of BIA-ALCL are not fully understood. This review aims to describe the current understanding around the environmental and molecular drivers of BIA-ALCL as well as the genetic and chromosomal abnormalities identified in this disease to date.

Various Properties of Silicone Breast Implant Surfaces and Multimodal Techniques for the Functional Surface Modification

"Silicone breast implants are the most widely used medical devices for breast reconstruction and augmentation, and revision, but even after more than 60 years of use they are associated with multiple continued complications. Using advancement in current technologies, researchers are attempting to create an optimal implant surface for patients. Through these efforts, plastic surgeons and material researchers have made great progress in the field of implant research. Multimodal techniques for the functional modification of implant surfaces will contribute to further the development of ideal biomaterials useful in breast implants.

Co-effects of C/Ag dual ion implantation on enhancing antibacterial ability and biocompatibility of silicone rubber

Although silicone implants are the most popular choice around the world for breast augmentation, reconstruction, and revision, due to the poor antibacterial properties and limited biocompatibility of silicone rubber (SR), one of the major complications, capsule contracture, is a lingering problem. To overcome the two main shortcomings, a dual ion implantation technique was applied to modify the surface of SR with the basic skeleton element of organic matter, carbon (C) and the broad-spectrum bactericide, silver (Ag). We present surface characterization, toxicological effects, and evaluation of the mechanical, antibacterial and biocompatible properties of C and Ag co-implanted SR (C/Ag-SRs). After ion implantation, surface roughness and tensile strength of these new materials increased. Biotoxicity was fully assessed by in vitro experiments on human fibroblasts and in vivo experiments on rats, showing that the low-Ag groups met safety standards. Both the anti-bacterial adhesion and bactericidal abilities of C/Ag-SRs were superior to those of SR, which had few antibacterial activities, especially against Staphylococcus epidermidis. With respect to biocompatibility, the adhesion of fibroblasts was promoted, while their proliferation was moderately inhibited on ion-implanted surfaces. After subcutaneous implantation in rats for 7, 30, 90 and 180 d, the capsular thickness around C/Ag-SRs was significantly lower than that around the SR. Additionally, there was no difference in the inflammatory reaction after 7 d of retention in vivo between C/Ag-SRs and SR. The results demonstrate that C/Ag-SRs are desirable shell materials for breast implants.

A biocompatible vascularized graphene oxide (GO)-collagen chamber with osteoinductive and anti-fibrosis effects promotes bone regeneration in vivo

The survival of transplanted cells and tissues in bone regeneration requires a microenvironment with a vibrant vascular network. A tissue engineering chamber can provide this in vivo. However, the commonly used silicone chamber is biologically inert and can cause rejection reactions and fibrous capsule. Studies have revealed that collagen is highly biocompatible and graphene oxide (GO) could regulate osteogenic activity in vivo. Besides, GO can be cross-linked with natural biodegradable polymers to construct scaffolds.

Methods: A vascularized GO-collagen chamber model was built by placing vessels traversing through the embedded tissue-engineered grafts (osteogenic-induced bone mesenchymal stem cells -gelatin) in the rat groin area. Osteogenic activity and inflammatory reactions were assessed using different methods including micro-CT scanning, Alizarin red staining, and immunohistochemical staining.

Results: After one month, in vivo results showed that bone mineralization and inflammatory responses were significantly pronounced in the silicone model or no chamber (control) groups. Vascular perfusion analysis confirmed that the GO-collagen chamber improved the angiogenic processes. Cells labeled with EdU revealed that the GO-collagen chamber promoted the survival and osteogenic differentiation of bone mesenchymal stem cells.

Conclusion: Overall, the novel biocompatible GO-collagen chamber exhibited osteoinductive and anti-fibrosis effects which improved bone regeneration in vivo. It can, therefore, be applied to other fields of regenerative medicine.

Size matters-in vitro behaviour of human fibroblasts on textured silicone surfaces with different pore sizes

Capsular contracture remains a challenge in plastic surgery and represents one of the most common postoperative complications following alloplastic breast reconstruction. The impact of the surface structure of silicone implants on the foreign body reaction and the behaviour of connective tissue-producing cells has already been discussed. The aim of this study was to investigate different pore sizes of silicone surfaces and their influence on human fibroblasts in an in vitro model. Four different textures (no, fine, medium and coarse texture) produced with the salt-loss technique, have been assessed in an in vitro model. Human fibroblasts were seeded onto silicone sheets and evaluated after 1, 4 and 7 days microscopically, with viability assay and gene expression analysis. Comparing the growth behaviour and adhesion of the fibroblasts on the four different textures, a dense cell layer, good adhesion and bridge-building ability of the cells could be observed for the fine and medium texture. Cell number and viability of the cells were increasing during the time course of experiments on every texture. TGFß1 was lowest expressed on the fine and medium texture indicating a trend for decreased fibrotic activity. For silicone surfaces produced with the salt-loss technique, we were able to show an antifibrotic effect of smaller sized pores. These findings underline the hypothesis of a key role of the implant surface and the pore size and pore structure in preventing capsular contracture.

Role of mechanical and thermal damage in pericapsular inflammatory response to injectable silicone in a rabbit model

Silicone is used widely for tissue augmentation in humans. However, late complications, such as delayed inflammation and capsular contracture, remain uncharacterized, despite their importance. In the present study, we aimed to determine whether mechanical and thermal damage induce capsular inflammation around a foreign body, and elucidate the biological mechanism underlying this phenomenon. We injected silicone into the subcutaneous layer of the skin of New Zealand white rabbits. The rabbits were divided into two groups: the control group received no treatment; in the experimental group, external force was applied near the injection silicone using high-intensity focused ultrasound (HIFU). Tissues near the injected silicone were harvested from both groups on Days 4, 7, and 30 after HIFU treatment for comparative analysis. Visual and histological examinations showed clearly increased inflammation in the experimental group compared with that in the control group. Furthermore, capsular tissue from the experimental group displayed markedly increased collagen production. Immunofluorescence revealed marked activation of macrophages in the early stages of inflammation (Days 4 and 7 after HIFU treatment), which decreased on Day 30. Assessment of cytokine activation showed significantly increased expression of heat shock protein (HSP)27, HSP60, HSP70, toll-like receptor (TLR)2, TLR4, and interleukin-8 in the experimental group. The expression of transforming growth factor-β1 did not increase significantly in the experimental group. In conclusion, damage to tissues around the injected silicone induced capsular inflammation. Macrophages and damage-associated molecular pattern molecules were involved in the early stages of inflammation. HSP release activated TLRs, which subsequently activated innate immunity and induced the inflammatory response.