Evaluation of Safe Systemic Immunosuppression Created with Dexamethasone in Prevention of Capsular Contracture: A Glance to Distinct Perspectives with Toll-Like Receptors

Effect of ASC Injection in the Inflammatory Reaction in Silicone Implant Capsule: Animal Model

Background

Capsular contracture is a common complication affecting about 80% of patients who receive radiotherapy after breast reconstruction with silicone prostheses. This study examines the use of adipocyte stem cells (ASCs) to treat capsular contracture.

Methods

Thirty rats were operated on to implant a minisilicone prosthesis in the dorsal region. The rats were divided into three groups: control (saline solution injection), radiotherapy (RDT), and RDT + ASC. After 3 months, the capsules were collected and submitted to histological analysis for inflammatory cell presence, vascular density, and collagen fibers, and gene expression of Tnf, Il1rap, Il10, Cd68, Mmp3, and Mmp9 by qPCR.

Results

In macroscopic analysis, the RTGO score showed a two-point reduction in RDT + ASC compared with the RDT (P = 0.003). In histological analysis, ASC exhibited less than 50% of inflammatory cells compared with RDT (P = 0.004), which was similar to control. This study demonstrated that Il1rap gene expression was identical in both RDT and RTD + ASC. Compared with control, treatment with ASC reduced Il1rap expression by 30%. Cd68 and Mmp3 expression levels were similar in both the control and RTD + ASC.

Conclusion

This study suggests that ASC treatment decreases silicone prosthesis capsule inflammation.

Latest advances: Improving the anti-inflammatory and immunomodulatory properties of PEEK materials

Excellent biocompatibility, mechanical properties, chemical stability, and elastic modulus close to bone tissue make polyetheretherketone (PEEK) a promising orthopedic implant material. However, biological inertness has hindered the clinical applications of PEEK. The immune responses and inflammatory reactions after implantation would interfere with the osteogenic process. Eventually, the proliferation of fibrous tissue and the formation of fibrous capsules would result in a loose connection between PEEK and bone, leading to implantation failure. Previous studies focused on improving the osteogenic properties and antibacterial ability of PEEK with various modification techniques. However, few studies have been conducted on the immunomodulatory capacity of PEEK. New clinical applications and advances in processing technology, research, and reports on the immunomodulatory capacity of PEEK have received increasing attention in recent years. Researchers have designed numerous modification techniques, including drug delivery systems, surface chemical modifications, and surface porous treatments, to modulate the post-implantation immune response to address the regulatory factors of the mechanism. These studies provide essential ideas and technical preconditions for the development and research of the next generation of PEEK biological implant materials. This paper summarizes the mechanism by which the immune response after PEEK implantation leads to fibrous capsule formation; it also focuses on modification techniques to improve the anti-inflammatory and immunomodulatory abilities of PEEK. We also discuss the limitations of the existing modification techniques and present the corresponding future perspectives.

Pharmacological Approaches for the Prevention of Breast Implant Capsular Contracture

Capsular contracture is a common complication associated with breast implants following reconstructive or aesthetic surgery in which a tight or constricting scar tissue capsule forms around the implant, often distorting the breast shape and resulting in chronic pain. Capsulectomy (involving full removal of the capsule surrounding the implant) and capsulotomy (where the capsule is released and/or partly removed to create more space for the implant) are the most common surgical procedures used to treat capsular contracture. Various structural modifications of the implant device (including use of textured implants, submuscular placement of the implant, and the use of polyurethane-coated implants) and surgical strategies (including pre-operative skin washing and irrigation of the implant pocket with antibiotics) have been and/or are currently used to help reduce the incidence of capsular contracture. In this article, we review the pharmacological approaches-both commonly practiced in the clinic and experimental-reported in the scientific and clinical literature aimed at either preventing or treating capsular contracture, including (i) pre- and post-operative intravenous administration of drug substances, (ii) systemic (usually oral) administration of drugs before and after surgery, (iii) modification of the implant surface with grafted drug substances, (iv) irrigation of the implant or peri-implant tissue with drugs prior to implantation, and (v) incorporation of drugs into the implant shell or filler prior to surgery followed by drug release in situ after implantation.

Autologous Conditioned Serum Increases Fat Graft Viability More than Platelet-Rich Plasma in a Controlled Rat Model

BACKGROUND

Platelet-rich plasma has been used to support fat graft retention, but it may include inflammatory mediators such as interleukin-1β. Autologous conditioned serum also contains high levels of various anti-inflammatory cytokines. The authors hypothesized that combining autologous conditioned serum with fat graft would increase fat graft survival more than platelet-rich plasma.

METHODS

Twenty-seven adult, male, Sprague-Dawley rats were divided into three groups of nine. Ten nonstudy rats were used to prepare platelet-rich plasma, autologous conditioned serum, and fat grafts. Next, 0.7-ml fat graft with a combination of 0.2 ml of autologous conditioned serum, platelet-rich plasma, or phosphate-buffered saline was applied to their dorsa. Fat graft volume was assessed on postoperative day 2 and on the day of euthanization at 1, 3, and 5 months postoperatively. Histopathologic analysis was performed to measure integrity, inflammation, fibrosis, and vascularization.

RESULTS

The median volume percentages and interquartile ranges at 1 month postoperatively were 97.3 percent (77.3 to 119.6 percent), 40.4 percent (30.9 to 46.9 percent), and 72.1 percent (53.6 to 84.9 percent) in autologous conditioned serum plus fat graft, phosphate-buffered saline plus fat graft, and platelet-rich plasma plus fat graft, respectively (p < 0.05); at 3 months postoperatively, values were 82.3 percent (70.3 to 88.3 percent), 36.6 percent (29.4 to 43.1 percent), and 48.3 percent (31.4 to 57.9 percent) (p < 0.001); and at 5 months postoperatively, values had increased to 83.9 percent (58.3 to 102.4 percent), 40.3 percent (20.1 to 50.6 percent), and 56.3 percent (37.7 to 74.9 percent), respectively (p < 0.05).

CONCLUSIONS

Autologous conditioned serum and platelet-rich plasma improved fat graft outcomes compared to saline, whereas autologous conditioned serum was associated with less inflammation, greater fat viability, and more integrity.

CLINICAL RELEVANCE STATEMENT

Combining fat graft with autologous conditioned serum may be a better option to minimize resorption rate and improve graft survival.

Capsular Contracture in Breast Implant Surgery: Where Are We Now and Where Are We Going?

Capsular contracture is the leading complication after surgery with breast implants. A lot of progress has been made investigating this complication over the years, and knowledge has been gained on this complication. Currently, the exact cause for capsular contracture is still unclear. It has been hypothesized that immunobiological factors (i.e., immunological and bacterial factors) and several risk factors play a central role in its development. In this paper, we give an overview of the known immunological factors that have been investigated in contracted and non-contracted capsules, as well as the role of bacterial formation around breast implants. We also report on risk factors that might increase the risk of capsular development. Lastly, it provides the latest research on this matter and discusses future perspectives as follow-up research is needed to unravel the pathogenic process leading to capsular contracture. This knowledge is of interest to establish medical therapies in order to prevent such side effects. Overall, capsular contracture seems to be a multifactorial condition consisting of several risk factors. LEVEL OF EVIDENCE V: 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 .

Acellular Dermal Matrix Reduces Myofibroblast Presence in the Breast Capsule

Background

Capsular contracture remains a common complication after implant-based breast reconstruction. Previous work has suggested that the use of acellular dermal matrix (ADM) reduces the rate of capsular contracture, though little is understood about the underlying mechanism. As myofibroblasts are believed to be the key cells implicated in contracture formation, we hypothesized that ADM would result in a reduction in periprosthetic myofibroblast concentration.

Methods

Five patients who underwent immediate prepectoral tissue expander placement with anterior ADM coverage and an inferior cuff were included. At the second stage, tissue samples were obtained of both ADM and capsule from each reconstructed breast. Samples were then prepared for hematoxylin and eosin staining and immunohistochemistry for myofibroblast identification (alpha smooth muscle actin and vimentin positive and desmin negative) and analysis. Experimental values are presented as mean ± SD unless otherwise stated. Statistical significance was determined using unpaired t test.

Results

Successful incorporation of ADM was noted in all cases. A significant reduction in myofibroblast concentration was noted in the ADM versus the capsule (P = 0.0018). This was paralleled by significantly thicker periprosthetic capsule formation overlying the formerly raw pectoralis major muscle, that is, not covered by ADM (P < 0.0001).

Conclusions

In the presence of ADM, there are significantly fewer myofibroblasts in breast capsules and thinner capsules on histology. Given the central role of myofibroblasts in the development of clinically significant capsular contracture, this study unmasks a possible mechanism for the protective effect of ADM with respect to capsular contracture development.