Modification of cysteinyl leukotriene receptors expression in capsular contracture: follow-up study and definitive results

Capsular inflammation after immediate breast reconstruction - Gene expression patterns and inflammatory cell infiltration in irradiated and non-irradiated breasts

BACKGROUND

Capsular contracture following post-mastectomy radiotherapy (PMRT) is commonly seen in patients undergoing implant-based immediate breast reconstruction (IBR). Further understanding of the underlying biology is needed for the development of preventive or therapeutic strategies. Therefore, we conducted a comparative study of gene expression patterns in capsular tissue from breast cancer patients who had received versus those who had not received PMRT after implant-based IBR.

METHODS

Biopsies from irradiated and healthy non-irradiated capsular tissue were harvested during implant exchange following IBR. Biopsies from irradiated (n = 13) and non-irradiated (n = 12) capsules were compared using Affymetrix microarrays to identify the most differentially regulated genes. Further analysis using immunohistochemistry was performed in a subset of materials to compare the presence of T cells, B cells, and macrophages.

RESULTS

Enrichment testing using Gene Ontology (GO) analysis revealed that the 227 most differentially expressed genes were mainly involved in an inflammatory response. Twenty-one GO biological processes were identified [p < 0.05, false discovery rate (FDR) < 5%], several with B-cell-associated inflammation. Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) analysis identified macrophages as the most common inflammatory cell type in both groups, further supported by immunostaining of CD68. Radiation remarkably increased B-cell infiltration in the capsular region of biopsies, as quantified by immunostaining of CD20 (p = 0.016).

CONCLUSIONS

Transcript analysis and immunohistochemistry revealed inflammatory responses in capsular biopsies regardless of radiotherapy. However, the radiation response specifically involved B-cell-associated inflammatory responses.

The Histological Composition of Capsular Contracture Focussed on the Inner Layer of the Capsule: An Intra-Donor Baker-I Versus Baker-IV Comparison

Background

Capsular contracture remains one of the major complications after breast implantation surgery. The extent of capsular contraction is scored using the Baker scale. The aim of this study was to compare intra-individual Baker-I with Baker-IV capsules, and in particular the prevalence and histological properties of the inner capsule layer.

Methods

Twenty capsules from ten patients were included after bilateral explantation surgery due to unilateral capsular contracture (Baker-IV) after cosmetic augmentation with textured implants. All capsules underwent (immune-)histochemical analysis: haematoxylin–eosin (morphology), CD68 (macrophages), cytokeratin (epithelial cells) and vimentin (fibroblasts), and were visually scored for cell density and the presence of an inner layer and measured for thickness.

Results

Baker-IV (n = 10) capsules were significantly thicker compared to Baker-I (n = 10) capsules (P = 0.004). An inner layer was present in 8 Baker-I capsules. All Baker-I capsules were vimentin and CD68-positive and cytokeratin-negative. Positive vimentin was seen throughout the inner layer, and CD-68 staining was observed adjacent to the intermediate capsule layer. In contrast, only 2 Baker-IV capsules had an inner layer, of which only 1 showed the same profile as Baker-I capsules (P = 0.016). No cytokeratin positivity was seen in any capsule. In Baker-IV capsules, outer layers showed more positivity for both vimentin and CD68.

Conclusion

The inner layer is morphologically consistent with synovial metaplasia and is more prevalent in healthy, uncontracted Baker-I capsules. This inverse relation between the presence of the inner layer and higher Baker classification or pathological contracture could indicate a protective role of the inner layer against capsular contracture formation.

Level of Evidence III

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Prophylactic Leukotriene Inhibitor Therapy for the Reduction of Capsular Contracture in Primary Silicone Breast Augmentation

Background:

The role of leukotriene inhibitors used immediately postoperatively to potentially influence the development of capsular contracture is unknown. The purpose of this study was to evaluate the incidence of capsular contracture among women undergoing primary smooth silicone gel breast augmentation, with or without postoperative leukotriene inhibitor therapy.

Methods:

Between 2007 and 2013, 1122 consecutive women undergoing primary silicone gel breast augmentation were evaluated retrospectively. All underwent augmentation with smooth, Mentor Memory Gel implants, using a dual-plane technique, with periareolar or inframammary approaches. Patients were treated voluntarily with either no leukotriene inhibitor, montelukast (Singulair), or zafirlukast (Accolate) for 3 months. All patients received informed consent for the off-label use of leukotriene inhibitors. Liver function studies were obtained for all patients undergoing Accolate therapy after 1 month of therapy. The presence of capsular contracture was measured by the Baker scale at 1 year postoperatively.

Results:

Patients receiving Accolate therapy (n = 520) demonstrated an encapsulation rate of 2.19 percent. Women receiving Singulair therapy (n = 247) had an encapsulation rate of 3.27 percent. Patients not receiving leukotriene inhibitor therapy had an encapsulation rate of 5.02 percent. There were no long-term complications among patients evaluated.

Conclusions:

Accolate therapy used for 3 months postoperatively was associated with significantly lower capsular contracture rates compared with untreated patients at 1-year follow-up (p < 0.05). Patients treated with Singulair demonstrated lower contracture rates compared with controls, but the differences were not statistically significant. The findings suggest that Accolate therapy, with monitoring and consent, reduces the incidence of capsular contracture following primary smooth silicone gel breast augmentation.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, III.

Simvastatin Reduces Capsular Fibrosis around Silicone Implants

Capsular fibrosis and contracture occurs in most breast reconstruction patients who undergo radiotherapy, and there is no definitive solution for its prevention. Simvastatin was effective at reducing fibrosis in various models. Peri-implant capsular formation is the result of tissue fibrosis development in irradiated breasts. The purpose of this study was to examine the effect of simvastatin on peri-implant fibrosis in rats. Eighteen male Sprague-Dawley rats were allocated to an experimental group (9 rats, 18 implants) or a control group (9 rats, 18 implants). Two hemispherical silicone implants, 10 mm in diameter, were inserted in subpanniculus pockets in each rat. The next day, 10-Gy of radiation from a clinical accelerator was targeted at the implants. Simvastatin (15 mg/kg/day) was administered by oral gavage in the experimental group, while animals in the control group received water. At 12 weeks post-implantation, peri-implant capsules were harvested and examined histologically and by real-time polymerase chain reaction. The average capsular thickness was 371.2 μm in the simvastatin group and 491.2 μm in the control group. The fibrosis ratio was significantly different, with 32.33% in the simvastatin group and 58.44% in the control group (P < 0.001). Connective tissue growth factor (CTGF) and transforming growth factor (TGF)-β1 gene expression decreased significantly in the simvastatin group compared to the control group (P < 0.001). This study shows that simvastatin reduces radiation-induced capsular fibrosis around silicone implants in rats. This finding offers an alternative therapeutic strategy for reducing capsular fibrosis and contracture after implant-based breast reconstruction.

Histologic, Molecular, and Clinical Evaluation of Explanted Breast Prostheses, Capsules, and Acellular Dermal Matrices for Bacteria

BACKGROUND

Subclinical infections, manifest as biofilms, are considered an important cause of capsular contracture. Acellular dermal matrices (ADMs) are frequently used in revision surgery to prevent recurrent capsular contractures.

OBJECTIVE

We sought to identify an association between capsular contracture and biofilm formation on breast prostheses, capsules, and ADMs in a tissue expander/implant (TE/I) exchange clinical paradigm.

METHODS

Biopsies of the prosthesis, capsule, and ADM from patients (N = 26) undergoing TE/I exchange for permanent breast implant were evaluated for subclinical infection. Capsular contracture was quantified with Baker Grade and intramammary pressure. Biofilm formation was evaluated with specialized cultures, rtPCR, bacterial taxonomy, live:dead staining, and scanning electron microscopy (SEM). Collagen distribution, capsular histology, and ADM remodeling were quantified following fluorescent and light microscopy.

RESULTS

Prosthetic devices were implanted from 91 to 1115 days. Intramammary pressure increased with Baker Grade. Of 26 patients evaluated, one patient had a positive culture and one patient demonstrated convincing evidence of biofilm morphology on SEM. Following PCR amplification 5 samples randomly selected for 16S rRNA gene sequencing demonstrated an abundance of suborder Micrococcineae, consistent with contamination.

CONCLUSIONS

Our data suggest that bacterial biofilms likely contribute to a proportion, but not all diagnosed capsular contractures. Biofilm formation does not appear to differ significantly between ADMs or capsules. While capsular contracture remains an incompletely understood but common problem in breast implant surgery, advances in imaging, diagnostic, and molecular techniques can now provide more sophisticated insights into the pathophysiology of capsular contracture.

LEVEL OF EVIDENCE

4 Therapeutic.

The effect of Zafirlukast on capsule formation in post-radiation silicone implants

Currently, breast cancer represents the most common indication for mastectomy with negative influence on personal perception, sexuality and partnership. Since the introduction of breast implants, silicone, and saline breast implantation have become one of the most common procedures performed by plastic surgeons, not only for aesthetic reasons but also for reconstructive purposes. These women will ultimately be faced with the prospect of capsular contracture. This is especially true in patients receiving radiation therapy, where irradiation increases the risk of complications, capsular contracture and may compromise a favorable aesthetic result. Despite the capsular contracture is the most common complication for both aesthetic and reconstructive breast surgery, the treatment have remained unsolved. Leukotriene antagonists (LTRAs) have emerged as effective prophylactic agents in the management of reactive airway diseases, and recently they have used as an off label prophylactic agent against the capsular contracture after breast augmentation. However up to now there is no any experimental research or clinical study in the medical literature about the effect of Zafirlukast on the capsular formation around irradiated silicone implants.

Effect of zafirlukast on capsular contracture around silicone implants in rats

PURPOSE

To evaluate the effect of zafirlukast on capsular contracture around silicone implants by measuring the pressure within the implant, using a rat experimental model.

METHODS

Forty adult female Wistar rats were used. Each one received two silicone implants, one with smooth-surface and the other with textured-surface. They were randomly divided into four groups (n=10). The rats of control group I were sacrificed after the implants. The remaining animals were subjected to a daily regimen of intra-peritoneal injection for a period of 90 days and they were distributed as follows: control group II received 0.9% physiological saline solution; experimental group I received zafirlukast 1.25 mg/kg; and experimental group II received zafirlukast 5 mg/kg. The measurement of intra-implant pressure of control group I was determined on the surgery day and in other groups on the ninetieth day, after being sacrificed.

RESULTS

In the evaluation of textured implants there was an increase of internal pressure in the control group II, and there was no increase in the experimental groups. Compared to the controls there were not significant differences in smooth implants.

CONCLUSION

Zafirlukast reduced the risk of developing capsular contracture around silicone implants with textured surface.