Periprosthetic breast capsules and immunophenotypes of inflammatory cells

Breast Implant Silicones and B Cell-Mediated Immune Responses: A Systematic Review of Literature

Introduction

Breast implants are under recent scrutiny owing to concerns about their potential for inducing immunological diseases, namely breast implant-associated anaplastic large cell lymphoma and breast implant illness. However, the impact of silicone on biologic systems remains unclear. Therefore, we performed a systematic literature review to evaluate the information available on silicone breast implants and their effect on one arm of the adaptive immune response-B lymphocytes and antibody formation.

Methods

We conducted a systematic review in EMBASE/PUBMED in accordance with the PRISMA guidelines, with search entry terms requiring discussion of silicone and immunity. The initial review returned 1079 citations. Manual screening was performed to include studies that were specific to the humoral response after exposure to silicone. Secondary full text review was performed. The extracted data included animal models and findings pertinent to B cells/antibodies in response to breast implant silicones.

Results

In total, 39 studies on B cells/antibodies and breast-implant-associated silicones were identified. Among them, 23 studies were in humans, 14 in animal models, and 2 were in vitro. Common themes included identification of antisilicone antibodies in women with breast implants, anticollagen antibodies, presence of activated B cells or immunoglobulin G in implant capsules, and sensitization of lymphocytes to silicone in vitro.

Conclusion

Despite controversial findings in the literature, there is evidence that silicone breast implants activate B cells in the breast implant capsule and may have systemic effects on the production of autoantibodies and/or sensitization of B lymphocytes to silicone. Further research is needed on how breast implants impact other arms of the immune system to understand their long-term biological impact.

The cellular and molecular properties of capsule surrounding silicone implants in humans vary uniquely according to the tissue type adjacent to the implant

The foreign body reaction (FBR) to biomaterials results in fibrous encapsulation. Excessive capsule fibrosis (capsular contracture) is a major challenge to the long-term stability of implants. Clinical data suggests that the tissue type in contact with silicone breast implants alters susceptibility to developing capsular contracture; however, the tissue-specific inflammatory and fibrotic characteristics of capsule have not been well characterized at the cellular and molecular level. In this study, 60 breast implant capsule samples are collected from patients and stratified by the adjacent tissue type including subcutaneous tissue, glandular breast tissue, or muscle tissue. Capsule thickness, collagen organization, immune and fibrotic cellular populations, and expression of inflammatory and fibrotic markers is quantified with histological staining, immunohistochemistry, and real-time PCR. The findings suggest there are significant differences in M1-like macrophages, CD4+ T cells, CD26+ fibroblasts, and expression of IL-1β, IL-6, TGF-β, and collagen type 1 depending on the tissue type abutting the implant. Subglandular breast implant capsule displays a significant increase in inflammatory and fibrotic markers. These findings suggest that the tissue microenvironment contributes uniquely to the FBR. This data could provide new avenues for research and clinical applications to improve the site-specific biocompatibility and longevity of implantable devices.

A morphological analysis of calcium hydroxylapatite and poly-l-lactic acid biostimulator particles

Injectable fillers, pivotal in aesthetic medicine, have evolved significantly with recent trends favoring biostimulators like calcium hydroxylapatite (CaHA-CMC; Radiesse, Merz Aesthetics, Raleigh, NC) and poly-l-lactic acid (PLLA; Sculptra Aesthetics, Galderma, Dallas, TX). This study aims to compare the particle morphology of these two injectables and examine its potential clinical implications. Utilizing advanced light and scanning electron microscopy techniques, the physical characteristics of CaHA-CMC and PLLA particles were analyzed, including shape, size, circularity, roundness, aspect ratio, and quantity of phagocytosable particles. The findings reveal several morphological contrasts: CaHA-CMC particles exhibited a smooth, homogenous, spherical morphology with diameters predominantly ranging between 20 and 45 µm, while PLLA particles varied considerably in shape and size, appearing as micro flakes ranging from 2 to 150 µm in major axis length. The circularity and roundness of CaHA-CMC particles were significantly higher compared to PLLA, indicating a more uniform shape. Aspect ratio analysis further underscored these differences, with CaHA-CMC particles showing a closer resemblance to circles, unlike the more oblong PLLA particles. Quantification of the phagocytosable content of both injectables revealed a higher percentage of phagocytosable particles in PLLA. These morphological distinctions may influence the tissue response to each treatment. CaHA-CMC's uniform, spherical particles may result in reduced inflammatory cell recruitment, whereas PLLA's heterogeneous particle morphology may evoke a more pronounced inflammatory response.

Biofilm-derived oxylipin 10-HOME-mediated immune response in women with breast implants

This study investigates a mechanistic link of bacterial biofilm-mediated host-pathogen interaction leading to immunological complications associated with breast implant illness (BII). Over 10 million women worldwide have breast implants. In recent years, women have described a constellation of immunological symptoms believed to be related to their breast implants. We report that periprosthetic breast tissue of participants with symptoms associated with BII had increased abundance of biofilm and biofilm-derived oxylipin 10-HOME compared with participants with implants who are without symptoms (non-BII) and participants without implants. S. epidermidis biofilm was observed to be higher in the BII group compared with the non-BII group and the normal tissue group. Oxylipin 10-HOME was found to be immunogenically capable of polarizing naive CD4+ T cells with a resulting Th1 subtype in vitro and in vivo. Consistently, an abundance of CD4+Th1 subtype was observed in the periprosthetic breast tissue and blood of people in the BII group. Mice injected with 10-HOME also had increased Th1 subtype in their blood, akin to patients with BII, and demonstrated fatigue-like symptoms. The identification of an oxylipin-mediated mechanism of immune activation induced by local bacterial biofilm provides insight into the possible pathogenesis of the implant-associated immune symptoms of BII.

The plasticity of biocompatibility

Biocompatibility concerns the phenomena that occur within the interactions between biomaterials and human patients, which ultimately control the performance of many facets of medical technology. It involves aspects of materials science, many different forms of engineering and nanotechnology, chemistry, biophysics, molecular and cellular biology, immunology, pathology and a myriad of clinical applications. It is not surprising that an overarching framework of mechanisms of biocompatibility has been difficult to elucidate and validate. This essay discusses one fundamental reason for this; we have tended to consider biocompatibility pathways as essentially linear sequences of events which follow well-understood processes of materials science and biology. The reality, however, is that the pathways may involve a great deal of plasticity, in which many additional idiosyncratic factors, including those of genetic, epigenetic and viral origin, exert influence, as do complex mechanical, physical and pharmacological variables. Plasticity is an inherent core feature of the performance of synthetic materials; here we follow the more recent biological applications of plasticity concepts into the sphere of biocompatibility pathways. A straightforward linear pathway may result in successful outcomes for many patients; we may describe this in terms of classic biocompatibility pathways. In other situations, which usually command much more attention because of their unsuccessful outcomes, these plasticity-driven processes follow alternative biocompatibility pathways; often, the variability in outcomes with identical technologies is due to biological plasticity rather than material or device deficiency.

Breast Implant-Associated Anaplastic Large Cell Lymphoma

Pathologic staging including assessment of margins is essential for the proper management of patients with breast implant-associated anaplastic large-cell lymphoma (BIA-ALCL). As most patients present with effusion, cytologic examination with immunohistochemistry and/or flow cytometry immunophenotyping are essential for diagnosis. Upon a diagnosis of BIA-ALCL, en bloc resection is recommended. When a tumor mass is not identified, a systematic approach to fixation and sampling of the capsule, followed by pathologic staging and assessment of margins, is essential. Cure is likely when lymphoma is contained within the en bloc resection and margins are negative. Incomplete resection or positive margins require a multidisciplinary team assessment for adjuvant therapy.

Tissue-Material Integration and Biostimulation Study of Collagen Acellular Matrices

Background:

Breast reconstruction after mastectomy using silicone implants is a surgical procedure that occasionally leads to capsular contracture formation. This phenomenon constitutes an important and persistent cause of morbidity, and no successful therapies are available to date. Recently, the use of acellular membranes as a protective material for silicone prostheses has been gaining attention due to their ability to prevent this adverse outcome. For this reason, the evaluation of the tissue-material integration and the induced biostimulation by acellular membranes results crucial. Evaluation of in vivo tissue integration and biostimulation induced by three different natural acellular collagen membranes.

Methods:

Scanning electron microscopy was performed to analyse the membrane porosity and cells-biomaterial interaction in vitro, both in dry and wet conditions. Adipose-derived stem cells were cultured in the presence of membranes, and the colonisation capacity and differentiation potential of cells were assessed. In vivo tests and ex vivo analyses have been performed to evaluate dermal integration, absorption degree and biostimulation induced by the evaluated membrane.

Results:

Analysis performed in vitro on the three different acellular dermal matrices evidenced that porosity and the morphological structure of membranes influence the liquid swelling ratio, affecting the cell mobility and the colonisation capacity. Moreover, the evaluated membranes influenced in different manner the adipose derived stem cells differentiation and their survival. In vivo investigation indicated that the absorption degree and the fluid accumulation surrounding the implant were membrane-dependent. Finally, ex vivo analysis confirmed the membrane-dependent behavior revealing different degree of tissue integration and biostimulation, such as adipogenic stimulation.

Conclusion:

The physico-chemical characteristics of the membranes play a key role in the biostimulation of the cellular environment inducing the development of well-organized adipose tissue.

Can Breast Implants Induce Breast Cancer Immunosurveillance? An Analysis of Antibody Response to Breast Cancer Antigen following Implant Placement

BACKGROUND

Women with cosmetic breast implants have significantly lower rates of subsequent breast cancer than the general population (relative risk, 0.63; 95 percent CI, 0.56 to 0.71). The authors hypothesize that breast implant-induced local inflammation stimulates immunosurveillance recognition of breast tumor antigen.

METHODS

Sera were collected from two cohorts of healthy women: women with long-term breast implants (i.e., breast implants for >6 months) and breast implant-naive women. Antibody responses to breast tumor antigens were tested by enzyme-linked immunosorbent assay and compared between cohorts by unpaired t test. Of the implant-naive cohort, nine women underwent breast augmentation, and antibody responses before and after implant placement were compared by paired t test.

RESULTS

Sera were collected from 104 women: 36 (34.6 percent) long-term breast implants and 68 (65.4 percent) implant-naive women. Women with long-term breast implants had higher antibody responses than implant-naive women to mammaglobin-A (optical density at 450 nm, 0.33 versus 0.22; p = 0.003) and mucin-1 (optical density at 450 nm, 0.42 versus 0.34; p = 0.02). There was no difference in antibody responses to breast cancer susceptibility gene 2, carcinoembryonic antigen, human epidermal growth factor receptor-2, or tetanus. Nine women with longitudinal samples preoperatively and 1 month postoperatively demonstrated significantly elevated antibody responses following implant placement to mammaglobin-A (mean difference, 0.13; p = 0.0002) and mucin-1 (mean difference 0.08; p = 0.02). There was no difference in postimplant responses to other breast tumor antigens, or tetanus.

CONCLUSIONS

Women with long-term breast implants have higher antibody recognition of mammaglobin-A and mucin-1. This study provides the first evidence of implant-related immune responses to breast cancer antigens.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

Association of the Implant Surface Texture Used in Reconstruction With Breast Cancer Recurrence

Importance

The potential association between breast implant-related anaplastic large cell lymphoma (BIA-ALCL) and implant texture has raised concerns about the additional unexpected adverse effects of textured implants, including potentially adverse outcomes for other cancers. In addition to the risk of developing BIA-ALCL, breast cancer survivors may worry about whether the type of implant inserted is associated with recurrence of their original cancer-an issue for which little evidence currently exists.

Objective

To evaluate the oncologic outcomes of breast cancer according to the surface type of implants used for reconstruction and to identify the independent factors associated with breast cancer recurrence and survival, including implant surface type.

Design, Setting, and Participants

This cohort study was conducted at Samsung Medical Center, a single tertiary referral center in Seoul, South Korea. Patients with breast cancer who underwent total mastectomy and immediate 2-stage tissue expander/implant reconstruction between January 1, 2011, and December 31, 2016, were identified from a prospectively maintained database. Patients were categorized into 2 groups according to the surface type of implant used for their reconstruction (smooth or textured implant). These patients were followed up for at least 2 years after insertion of the implant. Data analysis was performed from February 15, 2020, to March 5, 2020.

Exposures

Use of smooth implants vs textured implants at the second-stage operation.

Main Outcomes and Measures

The main outcomes of interest were local and regional recurrence-free survival (LRRFS) and disease-free survival (DFS) rates. Cumulative incidence of oncologic events in the smooth implant and textured implant groups and their respective hazard ratios (HRs) were collected and updated regularly.

Results

In total, 650 patients (all women, with a mean [SD] age of 43.5 [7.4] years), representing 687 cases, met the inclusion criteria and were followed up for a median (range) duration of 52 (31-106) months. Of the 687 cases, 274 (39.9%) received a smooth implant and 413 (60.1%) received a textured implant. Patients in these 2 surface texture groups had similar characteristics, including tumor staging (stage I: 102 [37.2%] vs 173 [41.9%]; stage II: 93 [33.9%] vs 119 [28.8%]; stage III: 14 [5.1%] vs 20 [4.8%]; P = .50) and rates of adjuvant radiotherapy (42 [15.3%] vs 49 [11.9%]; P = .19) and chemotherapy (113 [41.2%] vs 171 [41.4%]; P = .97). The 5-year LRRFS was 96.7%, and the 5-year DFS was 95.2%. Compared with the use of a smooth implant, textured implant use was statistically significantly associated with lower DFS, and this difference remained significant after adjusting for estrogen receptor (ER) status and tumor stage (HR, 3.054; 95% CI, 1.158-8.051; P = .02). Similar statistically significant associations were observed on multivariable analysis of patients with ER-positive cancer (HR, 3.130; 95% CI, 1.053-9.307; P = .04) and those with invasive cancer (HR, 3.044; 95% CI, 1.152-8.039; P = .03). The association of textured implant use with recurrence (lower DFS) was more prominent in cases with late-stage (stage II or III) tumor (HR, 8.874; 95% CI, 1.146-68.748; P = .04). The LRRFS did not differ statistically significantly according to implant surface texture.

Conclusions and Relevance

This cohort study found that use of textured implants in reconstruction appears to be associated with recurrence of breast cancer. Further investigation is required to verify these results.

SEM and TEM for identification of capsular fibrosis and cellular behavior around breast implants - a descriptive analysis

BACKGROUND

Capsular fibrosis (CF) is the most common long-term complication in implant-based breast augmentation. It is well accepted that the foreign body response (FBR) instigates the development of fibrotic disease. Our study aims to compare murine and human samples of CF and describe the cellular and extracellular matrix (ECM) composition using scanning and transmission electron microscopy (SEM and TEM).

RESULTS

Miniature microtextured silicone breast implants were implanted in mice and subsequently harvested at days 15, 30, and 90 post-operation. Isolated human capsules with the most aggravated form of CF (Baker IV) were harvested post-operation. Both were analyzed with SEM and TEM to assess cellular infiltration and ECM structure. An architectural shift of collagen fiber arrangement from unidirectional to multidirectional was observed at day 90 when compared to days 15 and 30. Fibrosis was observed with an increase of histiocytic infiltration. Moreover, bacterial accumulation was seen around silicone fragments. These findings were common in both murine and human capsules.

CONCLUSIONS

This murine model accurately recapitulates CF found in humans and can be utilized for future research on cellular invasion in capsular fibrosis. This descriptive study helps to gain a better understanding of cellular mechanisms involved in the FBR. Increases of ECM and cellularity were observed over time with SEM and TEM analysis.

Breast Implant-associated Anaplastic Large Cell Lymphoma: A Review with Emphasis on the Role of Brentuximab Vedotin

Breast implant-associated anaplastic large cell lymphoma is a recently recognized complication of textured breast implants. It typically presents as unilateral peri-implant swelling approximately 7-10 years after implantation. While the course is usually indolent, breast implant-associated anaplastic large cell lymphoma may form a locally invasive mass and metastasize to regional lymph nodes or beyond to distant sites. Surgical excision has been well established as the standard of care for localized disease; however, guidelines directing management of advanced, recurrent or unresectable disease are based on limited and extrapolated evidence. The CD30-targeting immunoconjugate, brentuximab vedotin, has been utilized in this setting, typically in combination with chemotherapy. We recently reported a patient with unresectable breast implant-associated anaplastic large cell lymphoma who was treated with brentuximab vedotin monotherapy and has now sustained complete remission for 2.6 years. Herein, we provide an up-to-date review of the epidemiology, pathogenesis, clinical features, diagnosis and management of breast implant associated anaplastic large cell lymphoma with emphasis on the role of brentuximab vedotin.

Breast implant-associated anaplastic large cell lymphoma: a review

Breast implant-associated anaplastic large cell lymphoma is a newly recognized provisional entity in the 2017 revision of the World Health Organization Classification of Tumors of Hematopoietic and Lymphoid Tissues. It is an uncommon, slow growing T-cell lymphoma with morphology and immunophenotype similar to anaplastic lymphoma kinase-negative anaplastic large cell lymphoma. However, the presentation and treatment are unique. Breast implant-associated anaplastic large cell lymphoma often presents as a unilateral effusion confined to the capsule of a textured-surface breast implant, a median time of 9 years after the initial implants have been placed. Although it follows an indolent clinical course, breast implant-associated anaplastic large cell lymphoma has the potential to form a mass, to invade locally through the capsule into breast parenchyma or soft tissue and/or to spread to regional lymph nodes. In most cases, an explantation with a complete capsulectomy removing all disease, without chemotherapy is considered to be curative and confers an excellent event free and overall survival. Here we provide a comprehensive review of breast implant-associated anaplastic large cell lymphoma, including history, epidemiology, clinical features, imaging and pathology findings, pathologic handling, pathogenic mechanisms, model for progression, therapy and outcomes as well as an analysis of causality between breast implants and anaplastic large cell lymphoma.

Novel Approach for Risk-Reducing Mastectomy: First-Stage Implant Placement and Subsequent Second-Stage Mastectomy

BACKGROUND

Risk-reducing mastectomy with tissue expander and then implant-based breast reconstruction conventionally involved immediate submuscular placement of tissue expanders during mastectomy and then, after expansion, replacement of expanders for permanent implants in a second-stage operation. Use of acellular dermal matrix can achieve a single-stage operation; however, acellular dermal matrices are costly and may have potential complications. The authors aim to assess the feasibility of placement of implants as a first-stage procedure before risk-reducing mastectomy as a novel technique of reconstruction that avoids the need for serial outpatient expansion and acellular dermal matrix.

METHODS

Patients for whom risk-reducing mastectomy was planned were offered first-stage dual-plane placement of fixed volume silicone gel permanent implants by means of inframammary fold incisions. Risk-reducing mastectomy was undertaken several months later as the second operation, leaving the implants in place protected by the muscle and capsule pocket. Nipples were preserved or reconstructed according to the patient's choice.

RESULTS

Eight patients with 15 operated breasts were recruited. Anatomically shaped implants were used in all patients, and complete coverage of each implant was achieved. Mean implant volume was 433 ml (range, 290 to 545 ml). There were no complications, and good aesthetic outcomes were achieved.

CONCLUSIONS

This proof-of-principle study finds that placement of implants before risk-reducing mastectomy is a novel technique for women at high breast cancer risk that could reduce the use of tissue expanders and acellular dermal matrices and their associated problems. Two-stage risk-reducing mastectomy with first-stage implant placement and subsequent risk-reducing mastectomy leaving the implants in place is feasible, with no complications, and can produce a good cosmetic outcome.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Association of silicone breast implants and acute renal allograft rejection

Silicone may, like any other adjuvant, induce an inflammatory reaction and diseases. There is no data about its use in renal transplant recipients. Increased immunogenicity of silicon may manifest by activation of both the innate and the adaptive immune system cells what promotes a chronic pro-inflammatory response. Dendritic cells, macrophages, fibroblasts and T-cells have all been found at the capsule/silicone implant contact zone. Additionally, silicon may induce mononuclear cells to secrete proinflammatory cytokines IL-1β, IL-6 and TNF-α. Herein, we present two patients who developed acute rejection after breast augmentation and reconstruction with silicone-gel implants. By influencing the immunological and inflammatory response, silicone-gel may be involved in promotion of acute allograft rejection in renal transplant recipients. Further studies are needed to prove our hypothesis.

Breast Implant Texturization Does Not Affect the Crosstalk Between MSC and ALCL Cells

In the last decade, there has been a growing interest about the possible association between anaplastic large cell lymphoma (ALCL) and breast implants (BIA-ALCL). Many variables, such as breast implants texturization, have been investigated. Breast implants often lead to the formation of a periprosthetic capsule, characterized by inflammation. The presence of the inflamed capsule has been found in the majority of patients with BIA-ALCL. Inflammation may be sustained or counteracted by mesenchymal stem cells (MSCs) by the secretion of pro- or anti-inflammatory cytokines. MSCs were isolated from three capsules surrounding micro-textured (micro-MSCs) and from three capsules surrounding macro-textured (macro-MSCs) implants; after characterization, MSCs were co-cultured with KI-JK cells (a cell line derived from the cutaneous form of ALCL). The secretion of cytokines related to inflammation, the proliferation rate, and the expression of genes referred to pro-tumoral mechanisms were evaluated. Co-cultures of KI-JK cells with micro- or macro-MSCs gave the same results about the secretion of cytokines (increase of IL10, G-CSF, and TGF-β1 and decrease of IL4, IL5, IL12, IL13, IL17A, IFN-γ (p < 0.05) with respect to mock sample), expression of selected genes (increase for ACVR1, VEGF, TGF-βR2, CXCL12, and MKi67 (p < 0.05) with respect to control sample), and the proliferation rate (no variation between mock and co-cultured samples). Our results suggest that MSCs derived from capsules surrounding micro- and macro-textured implants display the same effects on the ALCL cells.

Immunophenotypic characterization of human T cells after in vitro exposure to different silicone breast implant surfaces

The most common complication of silicone breast implants is capsular contracture (massive scar formation around the implant). We postulate that capsular contracture is always a sequel to inflammatory processes, with both innate and adaptive immune mechanisms participating. In general, fibroblasts and macrophages have been used as cell types to evaluate in vitro the biocompatibility of breast implant surfaces. Moreover, also T cells have been found at the implant site at the initial stage of fibrous capsule formation. However, only few studies have addressed the influence of surfaces with different textures on T-cell responses. The aim of the present study was to investigate the immune response of human peripheral blood mononuclear cells (PBMC) to commercially available silicone breast implants in vitro. PBMC from healthy female blood donors were cultured on each silicone surface for 4 days. Proliferation and phenotype of cultured cells were assessed by flow cytometry. Cytokine levels were determined by multiplex and real-time assay. We found that silicone surfaces do not induce T-cell proliferation, nor do they extensively alter the proportion of T cell subsets (CD4, CD8, naïve, effector memory). Interestingly, cytokine profiling identified matrix specific differences, especially for IL-6 and TNF-α on certain surface topographies that could lead to increased fibrosis.

Relevant In Vitro Predictors of Human Acellular Dermal Matrix-Associated Inflammation and Capsule Formation in a Nonhuman Primate Subcutaneous Tissue Expander Model

Objective: Benchtop methods were evaluated for preclinical inflammation/capsule formation correlation following implantation of human acellular dermal matrices. Methods: Dermal matrices were compared with native dermis for structure (histology, scanning electron microscopy), collagen solubility (hydroxyproline), enzymatic susceptibility (collagenase), and thermal stability (differential scanning calorimetry). Results were compared with implantation outcomes in a primate tissue expander model. Results: Native dermis, electron beam-sterilized, and freeze-dried human acellular dermal matrices had equivalent morphology, acid-soluble collagen (60.5% ± 6.3%, 65.3% ± 3.2%, and 63.3% ± 2.4%, respectively), and collagenase resistance. Implant results showed minimal inflammation/matrix degradation, lack of capsule formation, insignificant elastic modulus change (57.65 ± 20.24 MPa out-of-package/44.84 ± 23.87 MPa in vivo), and low antibody induction (2- to 8-fold increase) for electron beam-sterilized matrix. Similar results for freeze-dried dermal matrix were previously observed. γ-Irradiated, γ-irradiated/freeze-dried, and ethanol-stored dermal matrices were statistically different from native dermis for acid-soluble collagen (82.4% ± 5.8%, 72.2% ± 6.2%, and 76.8% ± 5.0%, respectively) and collagenase digestion rate, indicating matrix damage. γ-Irradiated matrix-implanted animals demonstrated elevated inflammatory response, foreign body giant cells, capsule formation at the tissue expander junction, and robust matrix metalloproteinase-1 staining with significant elastic modulus decrease (37.43 ± 7.52 MPa out-of-package/19.58 ± 1.16 MPa in vivo). Antibody increase (32- to 128-fold) was observed 6 to 10 weeks following γ-irradiated matrix implantation. Ethanol-stored dermal matrix elicited an acute antibody response (4- to 128-fold increase, 2-4 weeks) and macrophage-concentrated synovial-like hyperplasia at the tissue expander junction, moderate matrix metalloproteinase-1 staining, and significant elastic modulus decrease (61.15 ± 9.12 MPa out-of-package/17.92 ± 4.02 MPa in vivo) by 10 weeks implantation. Conclusion: Demonstrated loss of collagen integrity in vitro may be predictive of inflammation/capsule formation in primate tissue expander models. These results may be further predictive of clinical observations.

Histone deacetylase inhibitors restore IL-10 expression in lipopolysaccharide-induced cell inflammation and reduce IL-1β and IL-6 production in breast silicone implant in C57BL/6J wild-type murine model

Among epigenetic enzymes, histone deacetylases (HDACs) are responsible for regulating the expression of an extensive array of genes by reversible deacetylation of nuclear histones as well as a large number of non-histone proteins. Initially proposed for cancer therapy, recently the interest for HDAC inhibitors (HDACi) as orally active, safe, and anti-inflammatory agents is rising due to their ability in reducing the severity of inflammatory and autoimmune diseases. In particular, selective HDAC3, HDAC6, and HDAC8 inhibitors have been described to downregulate the expression of pro-inflammatory cytokines (TNF-α, TGF-β, IL-1β, and IL-6). Herein, using KB31, C2C12, and 3T3-J2 cell lines, we demonstrated that, under lipopolysaccharide-induced in vitro inflammation, HDAC3/6/8 inhibitor MC2625 and HDAC6-selective inhibitor MC2780 were effective at a concentration of 30 ng/mL to downregulate mRNA expression of pro-inflammatory cytokines (IL-1β and IL-6) and to promote the transcription of IL-10 gene, without affecting the cell viability. Afterwards, we investigated by immunohistochemistry the activity of MC2625 and MC2780 at a concentration of 60 ng/kg animal weight to regulate silicone-triggered immune response in C57BL/6J female mice. Our findings evidenced the ability of such inhibitors to reduce host inflammation in silicone implants promoting a thickness reduction of peri-implant fibrous capsule, upregulating IL-10 expression, and reducing the production of both IL-1β and IL-6. These results underline the potential application of MC2625 and MC2780 in inflammation-related diseases.

Self-organization of "fibro-axonal" composite tissue around unmodified metallic micro-electrodes can form a functioning interface with a peripheral nerve: A new direction for creating long-term neural interfaces

INTRODUCTION

A long-term peripheral neural interface is an area of intense research. The use of electrode interfaces is limited by the biological response to the electrode material.

METHODS

We created an electrode construct to harbor the rat sciatic nerve with interposition of autogenous adipose tissue between the nerve and the electrode. The construct was implanted for 10 weeks.

RESULTS

Immunohistochemistry showed a unique laminar pattern of axonal growth layered between fibro-collagenous tissue, forming a physical interface with the tungsten micro-electrode. Action potentials transmitted across the intrerface showed mean conduction velocities varying between 6.99 ± 2.46 and 20.14 ± 4 m/s.

CONCLUSIONS

We have demonstrated the feasibility of a novel peripheral nerve interface through modulation of normal biologic phenomena. It has potential applications as a chronic implantable neural interface.

Silicone Implants with Smooth Surfaces Induce Thinner but Denser Fibrotic Capsules Compared to Those with Textured Surfaces in a Rodent Model

Purpose

Capsular contracture is the most frequent long-term complication after implant-based breast reconstruction or augmentation. The aim of this study was to evaluate the impact of implant surface properties on fibrotic capsule formation in an animal model.

Materials and Methods

Twenty-four rats received 1 scaled down silicone implant each; 12 of the rats received implants with textured surfaces, and the other 12 received implants with smooth surfaces. After 60 and 120 days, rats in each group underwent 7-Tesla Magnetic Resonance Imaging (MRI) and high-resolution ultrasound (HR-US), and specimens of the capsules were acquired and used to measure capsule thickness through histology, collagen density through picro sirius red staining, and analyses of expression of pro-fibrotic and inflammatory genes (Collagen1-4, TGFb1, TGFb3, Smad3, IL4, IL10, IL13, CD68) through qRT-PCR. Furthermore, MRI data were processed to obtain capsule volume and implant surface area.

Results

On day 60, histology and HR-US showed that fibrotic capsules were significantly thicker in the textured implant group with respect to the smooth implant group (p<0.05). However, this difference did not persist on day 120 (p=0.56). Capsule thickness decreased significantly over the study period in both smooth and textured implant groups (p<0.05). Thickness measurements were substantiated by MRI analysis and volumes changed accordingly. Implant surface area did not vary between study dates, but it was different between implant types. On day 60, the density of collagen in the fibrotic capsules was significantly lower in the textured implant group with respect to the smooth group (p<0.05), but again this difference did not persist on day 120 (p=0.67). Collagen 1 and CD68 were respectively over- and under expressed in the textured implant group on day 60. Significant differences in the expression of other genes were not observed.

Conclusion

Silicone implants with textured surfaces led to temporarily thicker but less dense fibrotic capsules compared with smooth surfaces. 7-Tesla MRI and HR-US are capable for non-invasive in-vivo assessment of capsular fibrosis in an animal model and can provide unique insights into the fibrotic process by 3D reconstruction and surface area measurement.

[Anaplasic large cell lymphoma after breast prosthesis removal: about a case]

There has recently been a new controversy about the appearance of a particular histological type of lymphoma, anaplasic large cell lymphoma, in patients carriers of breast implants, with no causal link has been established for the moment. We report the case of a patient of 67 years old with recurrent effusion breast after explantation of breast prosthesis. The diagnosis of anaplasic large cell lymphoma was made after histological examination of the entire peri-prosthetic capsule after removal of most common diagnoses such as infection. Taking in hematological load was then established with the administration of chemotherapy to complete remission. All peri-prosthetic recurrent effusion should suggest the diagnosis of anaplasic large cell lymphoma, the definitive diagnosis requires the completion of a total capsulectomy with histological examination of the entire capsule.

Breast Implant-Associated Anaplastic Large Cell Lymphoma: Report of 2 Cases and Review of the Literature

Although primary breast lymphomas are exceedingly rare, cases of breast implant-associated anaplastic large cell lymphoma (iALCL) continue to be reported. The authors describe their experience with 2 patients and review the literature. Both patients presented with periprosthetic fluid collection. Neither had evidence of systemic disease nor received systemic therapy. Both were disease free after bilateral capsulectomies and implant removal without implant replacement, and disease did not recur. During the literature review, 63 cases of iALCL (including our 2 patients) were identified. The median time from implant placement to diagnosis was 9 years. Both saline and silicone implants were associated with iALCL. Of the 26 cases for which implant surface was reported, the surface was textured in 24. Of the 58 patients with an identifiable presentation, 39 had periprosthetic fluid collection, including 7 with an associated mass; 13 had an isolated mass at presentation, including 1 with axillary adenopathy. Forty patients had capsulectomy, 7 of whom underwent implant replacement. Of the 44 patients with known treatment, 33 received chemotherapy and 23 received radiation. Of the 49 patients with known anaplastic large cell lymphoma, 15 had disease recurrence, and 4 patient deaths were reported. Of the 18 patients presenting with a mass, 11 had disease recurrence, including all 4 patients who died. This study represents the largest review of patients with iALCL described to date. Although most cases have an indolent clinical course, the variety of presentations defined as "seroma" vs "capsular involvement" emphasizes the importance of investigating a definitive method of diagnosis, management, and treatment of this disease. LEVEL OF EVIDENCE 5.

Comparative host response of 2 human acellular dermal matrices in a primate implant model

OBJECTIVE

We examined the differences in capsule formation between 2 commercially available human acellular dermal matrices in a nonhuman primate model.

METHODS

Primates were implanted dorsally with a subcutaneously placed tissue expander and randomized into 3 groups, receiving skin coverage only, coverage with non-irradiated freeze-dried human acellular dermal matrix, or coverage with gamma-irradiated human acellular dermal matrix. After 9 weeks, soft tissue around the tissue expander was excised and evaluated qualitatively and quantitatively to assess extent of inflammation (CD68 antibodies and interleukin-6 levels), degradation and fibrosis (matrix metalloproteinase-1 and procollagen-1 staining), and mechanical (tensile) strength.

RESULTS

Histological evaluation of tissue around the tissue expander indicated differences in host response, suggesting capsule presence in the gamma-irradiated matrix group but not the freeze-dried matrix group. The extent of local inflammation was much higher in the gamma-irradiated matrix group which demonstrated mean (standard deviation) localized interleukin-6 concentration of 67.3 (53.6) vs 16.3 (6.7) pg/mg protein in the non-irradiated matrix group. There was robust degradation and fibrotic response in the gamma-irradiated matrix group versus the freeze-dried matrix group. Mechanical testing indicated mean (standard deviation) ultimate tensile strength of 12.0 (7.1) N in the gamma-irradiated matrix group versus 99.3 (48.8) N in the freeze-dried matrix group.

CONCLUSIONS

Enclosure of a tissue expander with human acellular dermal matrix untreated by gamma irradiation led to minimal inflammation and minimal evidence of fibrosis/capsule around the tissue expander compared with robust capsule formation around the tissue expander that was covered by a gamma-irradiated human acellular dermal matrix.

Histopathological reaction over prosthesis surface covered with silicone and polyurethane foam implanted in rats

PURPOSES

To evaluate whether polyurethane foam leads more intense foreign-body reaction than silicone foam. To compare the vascularization of the capsules surrounding the foam implants. To investigate if the capsule of polyurethane foam implanted has greater amount of collagen than that of silicone foam.

METHODS

Sixty-four young male Wistar rats were allocated into two groups: polyurethane foam and silicone foam. Subcutaneous discs were implanted into the dorsum of the animals in both groups. The capsules were assessed 28 days, two months, three months and six months postoperatively. Microscopic analysis with H&E stain was performed to evaluate the acute and chronic inflammatory process, foreign-body reaction and neovascularization. The analysis with picrosirius red was performed using the ImageProPlus software, to measure the number of vessels and collagen types I and III.

RESULTS

There were no statistical differences between the two groups regarding the acute and chronic inflammatory processes. All rats from the polyurethane group, in all times, exhibited moderate or intense foreign-body reaction, with statistic significant difference (p=0.046) when compared with the silicone group, in which the reaction was either mild or nonexistent at two months. Vascular proliferation was significantly different between the groups at 28 days (p=0.0002), with the polyurethane group displaying greater neovascularization with H&E stain. Similar results were obtained with picrosirius red, which revealed in the polyurethane group a much greater number of vessels than in the silicone group (p=0.001). The collagen area was larger in the polyurethane group, significantly at 28 days (p=0.001) and at two months (p=0.030).

CONCLUSIONS

Polyurethane foam elicited more intense foreign-body reaction when compared with silicone foam. The number of vessels was higher in the capsules of the polyurethane foam implants 28 days after the operation. The capsule of the polyurethane foam implants showed a greater amount of collagen than that of the silicone foam implants.

[Two cases of lymphoma in an implant capsule: A difficult diagnosis, an unknown pathology]

The anaplastic large cell lymphoma (ALCL) is a rare disease, its incidence in the United States is one case per 500,000 women and three for 100 million patients for breast single location. Forty-six cases have been reported in the literature. They can grow on any type of implant: expander prosthesis silicone and saline, smooth or textured envelope. Currently, the consensus process includes capsulectomy, removal of the implant, chemotherapy and radiotherapy. However, some authors classify under indolent disease, but we believe that some cases may escape any therapeutic and become very aggressive forms. It is therefore important to make an early diagnosis and start treatment urgently. Severity and suspicion of iatrogenic nature of ALCL have an obligation to inform future with implants.