Botulinum Toxin A Affects Early Capsule Formation Around Silicone Implants in a Rat Model

The Effects of Botulinum Toxin Type A on the Biological Behavior of Fibroblasts on Silicone Implants

BACKGROUND

Capsular contracture is one of the most severe complications following breast augmentation surgery. It has been reported that botulinum toxin Type A (BTX-A) can inhibit capsular contracture, but the exact mechanisms remain unclear. Therefore, this study aims to explore the potential mechanisms behind BTX-A's inhibition of capsular contracture by observing its effects on the biological behavior of fibroblasts and its impact on the TGF-β/Smad signaling pathway.

METHODS

In vitro experiments involved culturing fibroblasts on PDMS surfaces, subsequently treating them with various concentrations of BTX-A. Fibroblast proliferation activity was assessed using the CCK-8 assay, while the migration and cytoskeletal morphology of the fibroblasts were meticulously examined. ELISA was utilized to quantify the expression of fibrosis-related cytokines. Gene and protein expressions related to the TGF-β/Smad pathway were analyzed through real-time PCR and Western blotting techniques.

RESULTS

BTX-A moderately enhanced the early proliferation and migration of fibroblasts on the surface of PDMS silicone sheets and reduced the synthesis of collagen types I and III. Furthermore, under the influence of BTX-A, the expression of TGF-βR2 and α-SMA in the TGF-β/Smad pathway was significantly inhibited.

CONCLUSIONS

This study demonstrates that BTX-A can inhibit fibroblast differentiation by downregulating the expression of TGF-βR2, thereby suppressing the TGF-β/Smad pathway. This suggests a possible mechanism through which BTX-A mitigates capsular contracture.

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 .

An Antifibrotic Breast Implant Surface Coating Significantly Reduces Periprosthetic Capsule Formation

BACKGROUND

The body responds to prosthetic materials with an inflammatory foreign body response and deposition of a fibrous capsule, which may be deleterious to the function of the device and cause significant discomfort for the patient. Capsular contracture (CC) is the most common complication of aesthetic and reconstructive breast surgery. The source of significant patient morbidity, it can result in pain, suboptimal aesthetic outcomes, implant failure, and increased costs. The underlying mechanism remains unknown. Treatment is limited to reoperation and capsule excision, but recurrence rates remain high. In this study, the authors altered the surface chemistry of silicone implants with a proprietary anti-inflammatory coating to reduce capsule formation.

METHODS

Silicone implants were coated with Met-Z2-Y12, a biocompatible, anti-inflammatory surface modification. Uncoated and Met-Z2-Y12-coated implants were implanted in C57BL/6 mice. After 21, 90, or 180 days, periprosthetic tissue was removed for histologic analysis.

RESULTS

The authors compared mean capsule thickness at three time points. At 21, 90, and 180 days, there was a statistically significant reduction in capsule thickness of Met-Z2-Y12-coated implants compared with uncoated implants ( P < 0.05).

CONCLUSIONS

Coating the surface of silicone implants with Met-Z2-Y12 significantly reduced acute and chronic capsule formation in a mouse model for implant-based breast augmentation and reconstruction. As capsule formation obligatorily precedes CC, these results suggest contracture itself may be significantly attenuated. Furthermore, as periprosthetic capsule formation is a complication without anatomical boundaries, this chemistry may have additional applications beyond breast implants, to a myriad of other implantable medical devices.

CLINICAL RELEVANCE STATEMENT

Coating of the silicone implant surface with Met-Z2-Y12 alters the periprosthetic capsule architecture and significantly reduces capsule thickness for at least 6 months postoperatively in a murine model. This is a promising step forward in the development of a therapy to prevent capsular contracture.

Treatment and Prevention of Periprosthetic Capsular Contracture in Breast Surgery With Prosthesis Using Leukotriene Receptor Antagonists: A Meta-Analysis

BACKGROUND

Capsular contracture (CC) is the most common long-term complication of breast surgery with prosthesis. Leukotriene receptor antagonists (LRAs) have been tested as a potential treatment; however, mixed results have been observed.

OBJECTIVES

The aim of this study was to undertake a meta-analysis to clarify the treatment and prophylactic capabilities of LRAs in the management of CC.

METHODS

A systematic literature search of the most popular English-language databases was performed to identify relevant primary publications. We included all studies that used the Baker scale to evaluate the treatment and preventive capabilities of LRAs.

RESULTS

Six eligible studies were included based on predefined inclusion and exclusion criteria, totalling 2276 breasts, of which 775 did not receive LRAs and 1501 did. Final pooled results showed that LRAs could help manage CC with a risk difference (RD) of -0.38 with a corresponding 95% CI of -0.69 to -0.08, showing statistical significance at a Z value of 2.48, P = 0.01. Subgroup analysis based on the type of drug showed that only montelukast yielded statistical significance (RD = -0.27, 95% CI = -0.51 to -0.03, Z = 2.20, P = 0.03). Zafirlukast did not seem to influence CC. Further subgroup analysis based on treatment timing showed that prophylaxis was ineffective and only treatment for ongoing CC yielded statistically significant improvements.

CONCLUSIONS

The current meta-analysis proved that LRAs could be used in the management of CC. Only treatment for ongoing CC showed statistically significant improvements. Montelukast seemed to be more efficient with a safer profile for adverse effects, whereas zafirlukast yielded no statistically significant results.

LEVEL OF EVIDENCE: 4

Does methylene blue increases capsular contracture in immediate breast reconstruction with silicone implant? An experimental study

Recently, most of the immediate breast reconstructions following mastectomy are being carried out with the use of silicone implants. In these patients, methylene blue is being used for the detection of sentinel lymph nodes. This experimental study was performed to determine the effect of methylene blue on capsular contracture around breast implants. Thirty-two Sprague Dawley rats were divided into 4 groups. Custom made silicone blocks were placed on the back of animals. In group 1, the incision was closed without performing any additional procedure. In group 2 (control), 0.1 mL of 0.9% normal saline was instilled into the pocket. Group 3 and 4 (study groups) received 0.1 and 0.2 mL of 1% methylene blue, respectively. On postoperative day 60, implants and capsular tissue were extracted. Capsule formation was evaluated both macroscopically and microscopically. The histological evaluation included capsule thickness, inflammation, neovascularization, and fibrosis gradients. Regarding capsule thickness, there were statistically significant differences between groups 1-3, 1-4, 2-3, and 2-4. Although there were more moderate and severe inflammation gradients in groups III and IV, there was no significant difference regarding inflammation severity between control and study groups. In respect of vascular proliferation, there was a statistically significant difference between control and study groups. Similarly, fibrosis gradients were higher in both groups 3 and 4. The study showed that the injection of methylene blue around silicone implants enhanced the formation of capsular contracture. In this case, the degree of contracture was independent of the dose given. Abbreviations: CC: capsular contracture; MM: methylene blue; SLNB: sentinel lymph node biopsy; NS: normal saline; H&E: hematoxylin and eosin; D: dorsal; V: ventral; L: lateral; n: frequency.

Auxiliary usage of botulinum toxin A in plastic surgery in China

BACKGROUND

Currently, botulinum toxin A (BTA) is mainly used in the treatment of muscle spasms and in cosmetic procedures, and its cosmetic indications are expanding rapidly. There have been sporadic reports focused on the preoperative usage of BTA complementing plastic surgery. We briefly summarize the current experience of BTA complementing plastic surgery in China based on clinical experience.

METHODS

We reported a brief review of the preoperative use of BTA as an accessory to plastic surgery (blepharoplasty, chin augmentation, mandibular angle ostectomy, rhinoplasty, hyaluronic acid fillers injection for wrinkle reduction) based on previous studies and our experience.

RESULTS

Preoperative treatment with BTA in plastic surgery helps surgeons operate and results in better cosmetic results.

CONCLUSIONS

Preoperative BTA treatment can reduce the occurrence of surgical complications as well as improve the surgical results in some plastic surgeries. The procedure is suitable for clinical application and worth promoting.

Botulinum Toxin A Plays an Important Role in the Placement of Implants Deep Within the Pectoralis Major Muscle for Mammaplasty: A Systematic Review and Meta-analysis

BACKGROUND

Breast prosthesis implants have been safely and efficiently used in the plastic surgery department. With the increasing demand for aesthetics, these silicon implants were not only used in breast augmentation surgery but also in breast reconstruction after mastectomy. Nevertheless, breast prosthesis implantation brings a lot of complications, such as: postoperative chronic pain, capsule contracture, prosthesis displacement and prosthesis rupture and infection in severe cases. From the year 1998, botulinum toxin A (BTX-A), a neurotoxin, has been reported to be effective for pain control, capsule contracture lessening, expander enlargement and so on. However, those articles included all kinds of study types: randomized, double-blinded controlled trial (RCT), nonrandomized trial, retrospective analysis and case series, besides the outcomes were varied. To clarify how BTX-A acts at the mammaplasty field, we made this systematic review and meta-analysis.

PURPOSE

To review how BTX-A acts in the field of mammaplasty as well as discuss the relative mechanisms of BTX-A and the related research progress.

METHODS

We searched Pubmed, Embase, Cochrane, Web of science, Clinical trials, Wanfang Database and VIP from inception until March 2018 for papers reporting the use of BTX-A in the breast surgery using implants deep within the pectoralis major muscle. System review, viewpoints and case reports were excluded.

RESULTS

Ten articles met the criteria for inclusion including six prospective controlled (2 RCT; 4 other trails), three retrospective cohorts and one case series. These studies were all about patients using BTX-A during or after breast surgery with expanders or prostheses. A total of 682 patients were enrolled, 543 (79.61%) accepted BTX-A injection, 185 underwent mastectomies with immediate reconstruction, 13 with delayed reconstruction, 295 mastectomies with either immediate or delayed reconstruction and 189 with breast augmentation using silicone prostheses. The study time ranging from 4 months to 13 years, 15 patients (2.76%) received BTX-A injection more than two times, 9.2% received less than 75 U BTX-A, 34.3% 75-100 U, 0.18% 250 U, and in 56.4% the dosage was not stated. No complications associated with BTX-A were mentioned, almost all the studies reported efficacy for pain control. Other assessments included increased speed of expander enlargement and volume were mentioned in four papers, two articles analyzed the visual analogue scores, three suggested relief of capsular contracture, two reported lower narcotic use, three mentioned shorter hospital stays and one proved lowering the rate of unplanned expander. It seems all the studies demonstrate the valid usage of BTX-A, but the quality of this evidence still under the line.

CONCLUSION

We could try to use BTX-A as a new method in the field of mammaplasty. There are so many advantages such as postoperative pain relief, reducing the hospital stay, and increasing operation success rate, but rigorous methodological evidence is still lacking. A lot of studies were retrospective, only two studies used the RCT method. Therefore, to obtain strong evidence to clarify the usage of BTX-A, more randomized double-blinded controlled trials will be required, meanwhile the mechanism study adds to the evidence.

LEVEL OF EVIDENCE III

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 .

Evaluation of botulinum toxin type A effectiveness in preventing postoperative intraperitoneal adhesions

Purpose

Postoperative intraperitoneal adhesions (PIAs) are one of the most important problems surgeons have to face after laparotomies. In this study, we aimed to evaluate the effectiveness of local application of botulinum toxin type A (BoNT-A) in various dosages on the prevention of intra-abdominal adhesions in rats with experimental intra-abdominal adhesions.

Methods

Forty Wistar Albino female rats were randomly separated into 4 groups. The 4 groups were determined as follows: Control (group 1, n = 10); Sham (group 2, n = 10); 10-µg/kg low-dose BoNT-A (group 3, n = 10) and 30-µg/kg high-dose BoNT-A (group 4, n = 10). Subserosal injuries were created on the caecum of all rats. Laparotomy was performed on the fifth day. Adhesion scores, histopathological examination, and E-cadherin expression levels were evaluated.

Results

General adhesion scores for groups 1 and 2 were determined to be significantly high when compared to group 4 (P < 0.001). A significant difference was also determined between groups 3 and 4 in terms of general adhesion scores (P < 0.05). In pair comparisons, a significant decrease in high-dose BoNT-A group (group 4) when compared to groups 1 and 2 in terms of neovascularization, fibroblast density, collagen deposition and inflammatory cell count was determined (P < 0.05).

Conclusion

A significant decrease was observed only in postoperative PIAs in the high-dose BoNT-A group between all 4 rat-groups with experimentally created postoperative PIAs. In this study, high-dose BoNT-A is determined to be an effective agent in preventing postoperative PIAs.

Human Embryonic Stem Cell-Derived Endothelial Precursor Cell Conditioned Medium Reduces the Thickness of the Capsule Around Silicone Implants in Rats

BACKGROUND

We postulated that the fibrotic capsule around a silicone implant could be induced by ischemic conditions, based on previous reports that hypoxia is an important microenvironmental factor in the development of tissue fibrosis.

OBJECTIVE

This study aimed to determine the effect of human embryonic stem cell (hESC)-derived endothelial precursor cell (EPC) conditioned medium (CM), which has strong angiogenic potential, on the development of capsule around the silicone implant in a rat model.

METHODS AND MATERIALS

Three groups had a mini-silicone implant with a smooth surface inserted. In 2 experimental groups, hESC-EPC CM was administered into the subcutaneous pocket either 1 or 2 times. After 2 months, the capsules were harvested and analyzed by histologic examination.

RESULTS

There was a significant reduction in the thickness of the peri-implant capsules (P < 0.05) between the control and experimental groups. There is no tendency that hESC-EPC CM reduces inflammatory reaction in early postoperative periods. The experimental group showed increased angiogenesis compared to the control group (P < 0.05).

CONCLUSIONS

Tissue hypoxia around the implant may be another cause for the peri-implant capsule. A preventive or therapeutic strategy to decrease capsular contracture by relieving the ischemic condition around the implant can be investigated in the future.

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.

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.