Effect of Antiadhesion Barrier Solution and Fibrin on Capsular Formation After Silicone Implant Insertion in a White Rat Model

Identification of Drug Compounds for Capsular Contracture Based on Text Mining and Deep Learning

BACKGROUND

Capsular contracture is a common and unpredictable complication after breast implant placement. Currently, the pathogenesis of capsular contracture is unclear, and the effectiveness of nonsurgical treatment is still doubtful. The authors' study aimed to investigate new drug therapies for capsular contracture by using computational methods.

METHODS

Genes related to capsular contracture were identified by text mining and GeneCodis. Then, the candidate key genes were selected through protein-protein interaction analysis in Search Tool for the Retrieval of Interacting Genes/Proteins and Cytoscape. Drugs targeting the candidate genes with relation to capsular contracture were screened out in Pharmaprojects. Based on the drug-target interaction analysis by DeepPurpose, candidate drugs with highest predicted binding affinity were obtained eventually.

RESULTS

The authors' study identified 55 genes related to capsular contracture. Gene set enrichment analysis and protein-protein interaction analysis generated eight candidate genes. One hundred drugs targeting the candidate genes were selected. The seven candidate drugs with the highest predicted binding affinity were determined by DeepPurpose, including tumor necrosis factor alpha antagonist, estrogen receptor agonist, insulin-like growth factor 1 receptor, tyrosine kinase inhibitor, and matrix metallopeptidase 1 inhibitor.

CONCLUSION

Text mining and DeepPurpose can be used as a promising tool for drug discovery in exploring nonsurgical treatment to capsular contracture.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, V.

A multi-targeting bionanomatrix coating to reduce capsular contracture development on silicone implants

BACKGROUND

Capsular contracture is a critical complication of silicone implantation caused by fibrotic tissue formation from excessive foreign body responses. Various approaches have been applied, but targeting the mechanisms of capsule formation has not been completely solved. Myofibroblast differentiation through the transforming growth factor beta (TGF-β)/p-SMADs signaling is one of the key factors for capsular contracture development. In addition, biofilm formation on implants may result chronic inflammation promoting capsular fibrosis formation with subsequent contraction. To date, there have been no approaches targeting multi-facted mechanisms of capsular contracture development.

METHODS

In this study, we developed a multi-targeting nitric oxide (NO) releasing bionanomatrix coating to reduce capsular contracture formation by targeting myofibroblast differentiation, inflammatory responses, and infections. First, we characterized the bionanomatrix coating on silicon implants by conducting rheology test, scanning electron microcsopy analysis, nanoindentation analysis, and NO release kinetics evaluation. In addition, differentiated monocyte adhesion and S. epidermidis biofilm formation on bionanomatrix coated silicone implants were evaluated in vitro. Bionanomatrix coated silicone and uncoated silicone groups were subcutaneously implanted into a mouse model for evaluation of capsular contracture development for a month. Fibrosis formation, capsule thickness, TGF-β/SMAD 2/3 signaling cascade, NO production, and inflammatory cytokine production were evaluated using histology, immunofluorescent imaging analysis, and gene and protein expression assays.

RESULTS

The bionanomatrix coating maintained a uniform and smooth surface on the silicone even after mechanical stress conditions. In addition, the bionanomatrix coating showed sustained NO release for at least one month and reduction of differentiated monocyte adhesion and S. epidermidis biofilm formation on the silicone implants in vitro. In in vivo implantation studies, the bionanomatrix coated groups demonstrated significant reduction of capsule thickness surrounding the implants. This result was due to a decrease of myofibroblast differentiation and fibrous extracellular matrix production through inhibition of the TGF-β/p-SMADs signaling. Also, the bionanomatrix coated groups reduced gene expression of M1 macrophage markers and promoted M2 macrophage markers which indicated the bionanomatrix could reduce inflammation but promote healing process.

CONCLUSIONS

In conclusion, the bionanomatrix coating significantly reduced capsular contracture formation and promoted healing process on silicone implants by reducing myfibroblast differentiation, fibrotic tissue formation, and inflammation. A multi-targeting nitric oxide releasing bionanomatrix coating for silicone implant can reduce capsular contracture and improve healing process. The bionanomatrix coating reduces capsule thickness, α-smooth muscle actin and collagen synthesis, and myofibroblast differentiation through inhibition of TGF-β/SMADs signaling cascades in the subcutaneous mouse models for a month.

Smooth Muscle Alpha Actin Immunoexpression (α-Sma) and CD-117 Antibody (C-Kit) in Capsules Formed by Polyurethane Foam-Coated Silicone Implants and with Textured Surface: A Study on Rats

BACKGROUND

One of the undesirable complications that might occur after breast augmentation with silicone implants is capsular contracture. In its etiology, the relations between mast cells and myofibroblasts play an important role in collagen synthesis. Mast cells are able to activate fibroblasts into myofibroblasts, through paracrine secretions, inducing collagen production. The objectives of this study were to analyze the myofibroblast concentration through the α-SMA immunomarker and evaluate the intensity of mast cell expression against the C-Kit immunomarker.

MATERIAL AND METHOD

Sixty-four Wistar rats were used, divided into two groups (polyurethane foam and textured surface) with 32 animals in each. The animals received silicone implants on the back, below the panniculus carnosus, and after the determined period, they were killed and the capsules formed around the implants were studied. The capsules were analyzed employing the immunohistochemical technique, with the α-SMA and C-Kit immunomarkers in subgroups of 30, 50, 70 and 90 days.

RESULTS

The myofibroblast concentration was higher in the polyurethane group when compared to the textured group (30 days p = 0.105; 50 days p = 0.247; 70 days p = 0.014 and 90 days p = 0.536). The intensity of mast cell expression was more pronounced in the polyurethane group when compared to the textured group (30 days p = 0.798; 50 days p = 0.537; 70 days p = 0.094 and 90 days p = 0.536).

CONCLUSIONS

Polyurethane-coated implants induced higher concentrations of myofibroblasts and higher expression of mast cells, when compared to the textured surface implants.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Effects of Medical Chitosan on Capsular Formation Following Silicone Implant Insertion in a Rabbit Model

BACKGROUND

Capsular contracture is a serious complication that occurs after breast implant surgery. This study was performed to confirm that medical chitosan (MC) affects capsule formation and elucidates a possible mechanism.

MATERIALS AND METHODS

In this study, we used 18 female adult New Zealand White rabbits. In each rabbit, two silicone implants were placed under the pectoralis muscle layer on both sides (one side was included in the experimental group and the other side was included in the control group). MC was applied around the silicone implant of the experiment group, while the control group received no treatment. The capsular thickness was calculated by Masson's trichrome stain. The expression of MMPs and TIMPs were determined by real-time PCR, Western blotting, and immunohistochemistry.

RESULTS

Compared to the control group, the capsular thickness of the MC group was significantly reduced at 4, 8, and 12 weeks after the operation (4 week: 229.3 ± 72.2 vs 76.1 ± 12.6 µm, p < 0.05; 8 week: 326.0 ± 53.8 vs 155.4 ± 61.7 µm, p < 0.0.5; 12 week: 151.2 ± 52.5 vs 60.0 ± 22.0 µm, p < 0.05). Compared to the control group, the MC group had significantly lower expressions of TIMP-1 and TIMP-2 (p < 0.05). However, compared to the control group, there was no statistically significant difference in the expressions of MMP-2 and MMP-9 in the experiment group (p > 0.05).

CONCLUSION

MC reduced the risk of developing capsular contracture around silicone implants, possibly by blocking the signaling pathway of TIMPs.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Capsular Contracture after Breast Augmentation: An Update for Clinical Practice

Capsular contracture is the most common complication following implant based breast surgery and is one of the most common reasons for reoperation. Therefore, it is important to try and understand why this happens, and what can be done to reduce its incidence. A literature search using the MEDLINE database was conducted including search terms 'capsular contracture breast augmentation', 'capsular contracture pathogenesis', 'capsular contracture incidence', and 'capsular contracture management', which yielded 82 results which met inclusion criteria. Capsular contracture is caused by an excessive fibrotic reaction to a foreign body (the implant) and has an overall incidence of 10.6%. Risk factors that were identified included the use of smooth (vs. textured) implants, a subglandular (vs. submuscular) placement, use of a silicone (vs. saline) filled implant and previous radiotherapy to the breast. The standard management of capsular contracture is surgical via a capsulectomy or capsulotomy. Medical treatment using the off-label leukotriene receptor antagonist Zafirlukast has been reported to reduce severity and help prevent capsular contracture from forming, as has the use of acellular dermal matrices, botox and neopocket formation. However, nearly all therapeutic approaches are associated with a significant rate of recurrence. Capsular contracture is a multifactorial fibrotic process the precise cause of which is still unknown. The incidence of contracture developing is lower with the use of textured implants, submuscular placement and the use of polyurethane coated implants. Symptomatic capsular contracture is usually managed surgically, however recent research has focussed on preventing capsular contracture from occurring, or treating it with autologous fat transfer.