Peptide growth factors and myofibroblasts in capsules around human breast implants

Cathelicidin LL-37 Expression in Human Breast Implant Capsules

BACKGROUND

Capsular contracture is the most common complication following breast implant placement. Cathelicidin LL-37 is a cationic peptide involved in innate immunity. Initially investigated for its antimicrobial role, it was found to have pleiotropic activities, such as immunomodulation, angiogenesis stimulation, and tissue healing. The aim of the study was to investigate the expression and localization of LL-37 in human breast implant capsules and its relationship with capsular formation, remodeling, and clinical outcomes.

METHODS

The study enrolled 28 women (29 implants) who underwent expander substitution with definitive implant. Contracture severity was evaluated. Specimens were stained with hematoxylin and eosin, Masson trichrome, immunohistochemistry, and immunofluorescence for LL-37, CD68, α-smooth muscle actin, collagen type I and type III, CD31, and Toll-like receptor-4.

RESULTS

LL-37 was expressed in macrophages and myofibroblasts of capsular tissue in 10 (34%) and nine (31%) of the specimens, respectively. In eight cases (27.5%), it was expressed by both macrophages and myofibroblasts of the same specimen. In infected capsules, expression by both cell types was found in all (100%) specimens. LL-37 expression by myofibroblasts positively correlated with its expression by macrophages ( P < 0.001). Moreover, LL-37 expression by macrophages of periexpander capsules negatively correlated with the severity of capsular contracture on definitive implants ( P = 0.04).

CONCLUSIONS

This study demonstrates the expression of LL-37 in macrophages and myofibroblasts of capsular tissue and its negative correlation with the severity of capsular contracture following permanent implant placement. Expression or up-regulation of LL-37 may be involved in myofibroblast and macrophage modulation, thus playing a role in the pathogenic fibrotic process underlying capsular contracture.

CLINICAL RELEVANCE STATEMENT

This is the first study to demonstrate LL37 expression in capsular tissue and to hypothesize its role in contracture and as a prognostic marker for contracture severity. If confirmed, medical strategies or implant coating could be implemented to reduce the risk of contracture for high-risk patients.

Systematic Review of Capsular Contracture Management following Breast Augmentation: An Update

BACKGROUND

Capsular contracture is one of the most frequent indications for revision following breast augmentation. Management goals focus on restoring breast aesthetics and minimizing subsequent recurrence of capsular contracture. As new data emerge, close review of the data are merited to build evidence-based clinical guidelines to inform surgical practice and management of capsular contracture.

METHODS

A systematic review of the MEDLINE, Embase, and Cochrane Database of Systematic Reviews databases was conducted to characterize the surgical management of capsular contracture in revision breast augmentations. The primary endpoint was capsular contracture recurrence rate.

RESULTS

The review was conducted in November of 2021. Primary search revealed 14,163 results. Initial screening by title left 1223 articles. Abstract review left 90 articles for full-text review, of which 34 were ultimately included and were all observational in nature.

CONCLUSIONS

Capsular contracture management remains an important topic, with limited high-level evidence for establishing clear evidence-based treatment guidelines. Although more evidence is required to assess the effects of capsulectomy, implant exchange, and plane change, these appear to be useful mechanisms for reducing recurrent capsular contracture. There is more evidence regarding the use of acellular dermal matrix, although this still requires long-term follow-up studies. New developments regarding textured implants limit the revision breast augmentation surgeon to smooth devices.

Advances on Capsular Contracture-Prevention and Management Strategies: A Narrative Review of the Literature

Capsular contracture (CC) is the most relevant complication of both aesthetic and reconstructive breast implant surgery. For many years, experimental and clinical trials have attempted to analyze CC risk factors, clinical features, and appropriate management strategies. It is commonly accepted that a multifactorial etiology promotes CC development. However, the heterogeneity in patients, implants and surgical techniques make it difficult to suitably compare or analyze specific factors. As a consequence, discordant data are present in literature, and a true systematic review is often limited in its conclusions. Hence, we decided to present a comprehensive review of current theories on prevention and management strategies, rather than a specific "solution" to this complication.

Methods

The PubMed database was searched for literature regarding CC prevention and management strategies. Pertinent articles in English, published before December 1, 2022, were compared with selection criteria and eventually included in this review.

Results

Through the initial search, 97 articles were identified, of which 38 were included in the final study. Several articles explored different medical and surgical preventive and therapeutic strategies, showing numerous controversies on appropriate CC management.

Conclusions

This review provides a clear overview of the complexity of CC. The wide variety of clinical situations in term of patients, implants, and surgical techniques prevent the standardization of CC management strategies. By contrast, a patient-customized approach should be preferred, and different strategies should be considered depending on the specific case. Further research is desirable to better ascertain evidence-based protocols with regard to CC prevention and treatment.

Progranulin Promotes the Formation and Development of Capsules Caused by Silicone in Sprague-Dawley Rats

Background

Silicone implants are currently the most widely used artificial materials in plastic surgery. Capsule formation following implant application is unavoidable. When the capsule is excessively thick and strongly contracted, it can lead to obvious symptoms, clinically known as capsular contracture. Biological factors have always been the focus of research on the capsule formation. As a growth factor, progranulin (PGRN) plays an important regulatory role in wound healing, tissue fibrosis, tumor proliferation and invasion, and inflammation regulation. At present, the research on the capsule mainly involves the regulation of tissue healing and fibrosis under the influence of inflammation. Because PGRN has a regulatory role in these processes, we believe that the study of both can provide a new theoretical basis and intervention sites for monitoring and inhibiting the development of the capsule.

Methods

In this experiment, the effects of different surgical operations on the content of PGRN in the surgical site and plasma of rats were detected. Sprague-Dawley (SD) rat dermal fibroblasts were co-cultured by recombinant PGRN. The effects of r-PGRN on fibroblasts were detected by 5-ethynyl-2’-deoxyuridine (EdU) assay, wound healing assay and Western blot assay. Finally, the effect of PGRN on capsule formation and contracture was studied by changing the content of PGRN in the prosthesis in rats after operation.

Results

Surgical trauma and silicone implant increased plasma and local PGRN levels in SD rats. PGRN can activate the TGF-β/SMAD signaling pathway in a dose-dependent manner, thereby promoting fibroblast proliferation, differentiation and migration and inhibiting apoptosis and enhancing cell function, thereby promoting capsule formation and contracture.

Conclusion

PGRN promotes the formation and contracture of the silicone implant capsule in SD rats by activating the TGF-β/SMAD signaling pathway. This discovery may provide new therapeutic targets and detection indicators.

The effect of implant surface on the recurrence rates of capsular contracture following revision breast surgery: Early results from a single surgeon retrospective comparative study

INTRODUCTION

This retrospective comparative study aimed to evaluate the effect of implant surface in two cohorts of consecutive patients who underwent revision surgery following capsular contracture (Baker III-IV) after primary breast augmentation with textured implants.

METHODS

All patients underwent the same surgical procedure (capsulectomy - pocket plane change - implant exchange) and the only difference was that two different types of implants were used during the implant exchange: textured(Group A - biocell) or nanotextured(Group B - silksurface). A comparative analysis was performed using the following parameters: patients' demographics, age, the time between the primary breast augmentation and the revision surgery, the surgical and follow-up outcomes; and the incidence, timing, and capsular contracture recurrence.

RESULTS

Eighty consecutive females were included, Group A(textured): age of 35(19-65) years and time between primary and secondary surgery of 59(6-209) months; and Group B(nanotextured): age of 39(26-58) years and time between primary and secondary surgery of 65(7-218) months. For both groups, at a mean follow-up of 25(21-36) months for Group A(textured), and at a mean follow-up of 24(21-34) months for Group B(nanotextured); capsular contracture reoccurred in 3 cases (7.5%), at 7, 10, and 14 months in Group A and in 3 cases (7,5%), at 9, 10, and 16 months in Group B, post revision surgery. Students' t-test demonstrated no statistically significant differences between the recurrences of the two implant surfaces (p-value>0.05).

CONCLUSION

In capsular contracture revision surgery, the type of implant surface (textured or nanotextured) does not appear to influence recurrence rates. Further studies are required to identify the clinical impact on the implant surface in long-term outcomes of capsular contracture breast surgery.

Angiotensin-Converting Enzyme Inhibitor Reduces Radiation-Induced Periprosthetic Capsular Fibrosis

BACKGROUND

The capsular contracture is one of the main complications after radiotherapy in patients with implant-based reconstruction. The aim of this study is to evaluate the efficacy of ramipril for the prevention of radiation-induced fibrosis around the silicone implant.

MATERIALS AND METHODS

Thirty Wistar rats in 5 groups were used. Group 1: implant; group 2: implant + radiation; group 3: ramipril + implant; group 4: ramipril + implant + radiation; group 5: sham. Ramipril treatment was started 5 d before surgery and continued for 12 wk after surgery. A mini silicone implant was placed in the back of the rats. A single fraction of 21.5 Gy radiation was applied. Tissues were examined histologically and immunohistochemically (TGF-β1, MMP-2, and TIMP-2 expression). The alteration of plasma TGF-β1 levels was examined before and after the experiment.

RESULTS

After applying implant or implant + radiation, capsular thickness, percentage of fibrotic area, tissue and plasma TGF-β1 levels significantly increased, and MMP-2/TIMP-2 ratio significantly decreased compared with the sham group. In ramipril-treated groups, the decrease in capsular thickness, fibrosis, TGF-β1 positivity, and an increase in MMP-2/TIMP-2 ratio were found significant. In the ramipril + implant + radiation group, the alteration values of TGF-β1 dramatically decreased.

CONCLUSIONS

Our results show that ramipril reduces radiation-induced fibrosis and contracture. The results of our study may be important for the design of the clinical trials required to investigate the effective and safe doses of ramipril, which is an inexpensive and easily tolerated drug, on humans.

Comprehensive Comparison Between Shaped Versus Round Implants for Breast Reconstruction: A Systematic Review and Meta-Analysis

BACKGROUND

Prosthetic breast reconstruction has been gaining popularity and a variety of implant options are currently available. Therefore, it is important to evaluate the safety and efficacy of newly developed shaped implants compared with those of conventional round implants. To date, few studies have investigated the outcomes of breast reconstruction with shaped versus round implants.

OBJECTIVES

The present study aimed to comprehensively compare, via meta-analytic methodology, shaped and round breast implant reconstruction in terms of complication profiles and aesthetic satisfaction.

METHODS

PubMed/MEDLINE, Ovid, and Cochrane databases were searched to identify relevant studies presenting the complication rates for shaped and round implant groups. The relative risks of the following complications between the groups were calculated: infection, seroma, capsular contracture, rupture, rippling, reconstruction failure, and implant exchange or removal. Outcomes of aesthetic satisfaction included aesthetic results and patient-reported outcomes.

RESULTS

Meta-analysis of 8 retrospective cohort studies, representing 2490 cases of implant-based breast reconstruction, was performed. There were no significant differences in the risks of infection, seroma, capsular contracture, and reconstruction failure between the 2 groups. The risks of implant rupture and rippling were significantly reduced with shaped implants. In a subgroup analysis of shaped/textured and round/smooth implants, the risk of infection was significantly enhanced in the former, whereas incidences of other complications, including capsular contracture and reconstruction failure, were similar. Aesthetic satisfaction analysis of the 2 groups demonstrated similar outcome scores with favorable overall results.

CONCLUSIONS

Our results suggest that both shaped and round implants might provide favorable breast reconstruction outcomes with similarly low complication rates and aesthetic results.

LEVEL OF EVIDENCE: 4

A Different Perspective on Breast Implant Surface Texturization and Anaplastic Large Cell Lymphoma (ALCL)

Anaplastic large cell lymphoma (ALCL) is a rare form of lymphoma involving cells of the immune system. It is currently gaining interest because of an association between the development of ALCL and an increased risk in women who have had breast implant surgery. Although not confirmed, many theories exist as to the etiology of this association in women, and there is growing concern that ALCL is more prevalent in women with textured breast implants. In particular, the risk of developing ALCL appears to be related to increasing implant texturization or "surface roughness." This paper examines the current manner of defining and characterizing breast implant surface texture and challenges the appropriateness of applying this technology and linking it to ALCL. It is not a comprehensive review of the etiology of capsular contracture and ALCL, but it proposes an alternative perspective on surface texture measurements from that currently employed and its role in researching the etiology of ALCL. The authors hope that their article will provoke thought and reflection when considering the issues currently being highlighted with regard to texturing of breast implants.

The role of angiogenesis, inflammation and estrogen receptors in breast implant capsules development and remodeling

BACKGROUND

Capsular contracture is the most common complication following breast implant placement. The multiple factors unbalancing the physiological response to the foreign body have not been fully elucidated. The aim of this study was to investigate the role of neo-angiogenesis, inflammation and estrogen receptors in peri-prosthetic tissue development and remodeling.

METHODS

The study enrolled 31 women who underwent expander substitution with definitive implant. Specimens were stained with hematoxylin/eosin, Masson trichrome, immunohistochemistry and immunofluorescence for alpha-smooth muscle actin, estrogen receptor-α (ER-α), estrogen receptor-β (ER-β), Collagen type I and III, CD31 (as a marker of neo-angiogenesis) and vascular endothelial growth factor (VEGF). Inflammatory infiltration was quantified and analyzed. Transmission electron microscopy was performed for ultrastructural evaluation.

RESULTS

Myofibroblasts, mainly localized in the middle layer of capsular tissue, expressed VEGF, ER-α and ER-β. ER-β expression positively correlated with Collagen type I deposition (p= 0.025). Neo-angiogenesis was predominant in the middle layer. CD31 expression positively correlated with Collagen type I expression (p=0.009) and inflammatory infiltration grade (p= 0.004). The degree of inflammatory infiltration negatively correlated with the time from implantation (p = 0.022).

DISCUSSION

The middle layer is key in the development and remodeling of capsular tissue. Myofibroblasts produce VEGF, that induces neo-angiogenesis. New vessels formation is also correlated to the inflammatory response. Collagen deposition is associated with ER-β expression and neo-angiogenesis. These findings may prelude to targeted pharmacologic therapies able to control such interactions, thus hampering the self-sustaining loop promoting the progression of physiologic fibrosis toward pathologic contracture.

The aetiopathogenesis of capsular contracture: A systematic review of the literature

BACKGROUND

Capsular contracture is the most frequent complication after breast augmentation or reconstruction with breast implants. The immune system plays a prominent role in capsular contracture formation, albeit to an unknown extent. Bacterial contamination in situ has been hypothesized to be causative for capsular contracture. How this relates to the immunological processes involved is unknown. This article aims to provide an overview of immunological and bacterial factors involved in development of capsular contracture.

MATERIALS AND METHODS

We undertook a systematic literature review focused on immunological factors and microbiota in relation to capsular contraction around implants. This systematic review was performed in accordance with the PRISMA guidelines. PubMed, EMBASE, and the Cochrane databases were searched from inception up to October 2016. Included studies were assessed for the following variables: subject characteristics, number of capsules, primary indication for surgery, surgical procedure, follow-up or implant duration, study methods, type of antibiotics or medical therapies and outcomes related to microbiota and immunological factors.

RESULTS

Data on immunological factors and bacterial contamination were retrieved from 64 included studies. Notably the presence of macrophages and Staphylococcus epidermidis within capsules was often associated with capsular contracture.

CONCLUSION

This review provides a clear overview of the immunological factors associated with capsular contracture and provides a hypothetical immunological model for development of the disease. Furthermore, an overview of bacterial contamination and associations with capsular contracture has been provided. Follow-up research may result in clinical recommendations to prevent capsular contracture.

Follistatin and the Breast Implant Capsule

Supplemental Digital Content is available in the text.

Background:

Breast capsular contracture remains an elusive problem faced by plastic surgeons and is the leading long-term complication after breast implantation. Follistatin (Fst) is a protein with known anti-inflammatory and antifibrotic properties and has the potential to limit the severity of diseases associated with inflammation and fibrosis such as capsular contracture. The aim of this study was to examine the effect of Fst288 on capsular fibrosis around silicone implants in a mouse model.

Methods:

BALB/c mice were implanted subcutaneously with untreated silicone implants (baseline control). In the experimental group, immediately after silicone implant insertion, the implant pocket received either a single injection of 1 µg Fst288 or normal saline (internal control). The animals were killed at 3, 5, 7, 14, 28, and 90 days after surgery, and serum, implants, and the surrounding tissue were removed for histological and immunohistochemical analyses.

Results:

Fst288 treatment resulted in significant decreases in capsule thickness at 28 days (P < 0.05) and 3 months (P < 0.001), decreased collagen production at 14 days (P < 0.05) and 3 months (P < 0.01), decreased angiogenesis at 3 months (P < 0.001), decreased α-smooth muscle actin levels at 3 months (P < 0.05), and a decrease in the number of CD45+ cells at days 5 (P < 0.05) and 7 (P < 0.01), respectively, when compared with control implants.

Conclusions:

A single injection of Fst288 at the time of silicone implant insertion into the mice results in a significant reduction in pericapsular inflammation and capsular fibrosis.

Histological characterization of human breast implant capsules

Background

This study investigated the relationships between histomorphological aspects of breast capsules, including capsule thickness, collagen fiber alignment, the presence of α-smooth muscle actin (α-SMA)–positive myofibroblasts, and clinical observations of capsular contracture.

Methods

Breast capsule samples were collected at the time of implant removal in patients undergoing breast implant replacement or revision surgery. Capsular contracture was scored preoperatively using the Baker scale. Histological analysis included hematoxylin and eosin staining, quantitative analysis of capsule thickness, collagen fiber alignment, and immunohistochemical evaluation for α-SMA and CD68.

Results

Forty-nine samples were harvested from 41 patients. A large variation in histomorphology was observed between samples, including differences in cellularity, fiber density and organization, and overall structure. Baker I capsules were significantly thinner than Baker II, III, and IV capsules. Capsule thickness positively correlated with implantation time for all capsules and for contracted capsules (Baker III and IV). Contracted capsules had significantly greater collagen fiber alignment and α-SMA–positive immunoreactivity than uncontracted capsules (Baker I and II). Capsules from textured implants had significantly less α-SMA–positive immunoreactivity than capsules from smooth implants.

Conclusion

The histomorphological diversity observed between the breast capsules highlights the challenges of identifying mechanistic trends in capsular contracture. Our findings support the role of increasing capsule thickness and collagen fiber alignment, and the presence of contractile myofibroblasts in the development of contracture. These changes in capsule structure may be directly related to palpation stiffness considered in the Baker score. Approaches to disrupt these processes may aid in decreasing capsular contracture rates.

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.

Comparison of the postoperative incidence rate of capsular contracture among different breast implants: a cumulative meta-analysis

Background

A large number of clinical studies have reported that the different materials used in breast implants were a possible cause of the different incidence rates of capsular contracture observed in patients after implantation. However, this theory lacks comprehensive support from evidence-based medicine, and considerable controversy remains.

Objectives

In this study, a cumulative systematic review examined breast augmentation that used implants with textured or smooth surfaces to analyze the effects of these two types of implants on the occurrence of postoperative capsular contracture.

Methods

We conducted a comprehensive search of literature databases, including PubMed and EMBASE, for clinical reports on the incidence of capsular contracture after the implantation of breast prostheses. We performed a cumulative meta-analysis on the incidence of capsular contracture in order from small to large sample sizes and conducted subgroup analyses according to the prosthetic material used, the implant pocket placement, the incision type and the duration of follow-up. Relative risks (RR) and 95% confidence intervals (CI) were used as the final pooled statistics.

Results

This meta-analysis included 16 randomized controlled trials (RCTs) and two retrospective studies. The cumulative comparison of textured and smooth breast implants showed statistical significance at 2.13 (95% CI, 1.18-3.86) when the fourth study was entered into the analysis. With the inclusion of more reports, the final results indicated that smooth breast implants were more likely to be associated with capsular contracture, with statistical significance at 3.10 (95% CI, 2.23-4.33). In the subgroup analyses, the subgroups based on implant materials included the silicone implant group and the saline implant group, with significant pooled statistical levels of 4.05 (95% CI, 1.97-8.31) and 3.12 (95% CI, 2.19-4.42), respectively. According to implant pocket placement, a subglandular group and a submuscular group were included in the analyses, and only the subglandular group had a statistically significant pooled result of 3.59 (95% CI, 2.43-5.30). Four subgroups were included in the analyses according to incision type: the inframammary incision group, the periareolar incision group, the transaxillary incision group and the mastectomy incision group. Among these groups, only the pooled results of the inframammary and mastectomy incision groups were statistically significant, at 2.82 (95% CI, 1.30-6.11) and 2.30 (95% CI, 1.17-4.50), respectively. Three follow-up duration subgroups were included in the analyses: the one-year group, the two- to three-year group and the ≥five-year group. These subgroups had statistically significant results of 4.67 (95% CI, 2.35-9.28), 3.42 (95% CI, 2.26-5.16) and 2.71 (95% CI, 1.64-4.49), respectively.

Conclusion

In mammaplasty, the use of textured implants reduces the incidence of postoperative capsular contracture. Differences in implant pocket placement and incision type are also likely to affect the incidence of capsular contracture; however, this conclusion awaits further study.

Oestrogen receptor-alpha and -beta expression in breast implant capsules: experimental findings and clinical correlates

Myofibroblasts provide a force to decrease the surface area of breast implant capsules as the collagen matrix matures. 17-β-Oestradiol promotes myofibroblast differentiation and contraction. The aim of the study was to investigate the expression of oestrogen receptors α and β in capsular tissue. The study enrolled 70 women (80 capsules) who underwent expander or implant removal, following breast reconstruction. Specimens were stained with haematoxylin/eosin, Masson trichrome and immunohistochemistry and immunofluorescence stainings for alpha-smooth muscle actin (α-SMA), oestrogen receptor-alpha (ER-α) and oestrogen receptor-beta (ER-β). The relationship between anti-oestrogenic therapy and capsular severity was evaluated. A retrospective analysis of 233 cases of breast reconstruction was conducted. Myofibroblasts expressed ER-α, ER-β or both. In the whole sample, α-SMA score positively correlated with ER-α (p = 0.022) and ER-β expression (p < 0.004). ER-β expression negatively correlated with capsular thickness (p < 0.019). In capsules surrounding expanders α-SMA and ER-α, expressions negatively correlated with time from implantation (p = 0.002 and p = 0.016, respectively). The incidence of grade III-IV contracture was higher in patients who did not have anti-oestrogenic therapy (p < 0.036); retrospective analysis of 233 cases confirmed this finding (p < 0.0001). This study demonstrates the expression of oestrogen receptors in myofibroblasts of capsular tissue. A lower contracture severity was found in patients who underwent anti-oestrogenic therapy.

Experimental total wrapping of breast implants with acellular dermal matrix: a preventive tool against capsular contracture in breast surgery?

BACKGROUND

Capsular contracture remains a hitherto unsolved complication after implantation of silicone gel-filled breast prostheses. Based on clinical and experimental data, the use of an acellular dermal matrix as a sheath around implants may lead to lesser capsular contracture acting as a proposed biological environment mimicking wound bed tissue. The aim of our study was to analyse the tissue reaction after implantation of silicone prosthesis with and without an envelope of acellular dermal matrix.

METHODS

Implantation of 60 silicone prostheses in the back of Lewis rats were carried out, randomly paired taking one rat from group A and one from group B. Group A included implants completely enveloped with xenogenic acellular dermis and group B undraped silicone implants. At 3, 6 and 12 weeks postoperatively, the samples were explanted and subjected to histological and immunohistochemical evaluation.

RESULTS

A new myofibroblast tissue layer was identified in proximity to the implant in both groups. The thickness of the layer in group A was continuously thinner than in group B regarding the different explantation time points. Implants completely wrapped with acellular dermal matrix showed significantly lesser inflammatory signs at 3 and 12 weeks after implantation compared to controls. Cell proliferation after 12 weeks was significantly decreased in group A.

CONCLUSION

The slight myofibroblast layer and reduced rate of inflammation and proliferation in the treatment group show a positive effect of total acellular dermal matrix envelope and hypothesise the decrease of capsular contracture in long-term periods.

Controlled clinical trial with pirfenidone in the treatment of breast capsular contracture: association of TGF-β polymorphisms

BACKGROUND

Breast capsular contracture (BCC) is a commonly adverse event postmammoplastly characterized by an immune response mediated by cytokines and transforming growth factor (TGF)-β1 resulting in excessive synthesis and deposit of extracellular matrix around the breast implant. Presence of TGF-β1 polymorphisms has been associated as a risk factor to develop fibroproliferative diseases.

METHODS

This open, controlled, prospective, and pilot clinical trial with 6 months duration was carried out to evaluate the efficacy of 1800 mg a day, of oral Pirfenidone (PFD) in the treatment of BCC (Baker Score III/IV) postmammoplasty. Twenty BCC cases received PFD and 14 BCC control cases underwent capsulectomy after 6 months of enrollment. Both groups were followed up for 6 more months up to 12 months to determine the relapse in the absence of PFD. Determination of TGF-β1 polymorphisms was performed to establish a correlation with capsular contracture.

RESULTS

PFD group experienced BCC-reduction in all breasts 6 months after enrollment. Only 1 of 20 cases relapsed after follow-up. In capsulectomy group, 2 of 14 cases presented progression to grade IV during presurgical period. All capsulectomy cases relapsed at end of follow-up. Nearly hundred percent of all patients studied in this protocol had a profibrogenic homozygous TGF-β1 polymorphism (codon 25; genotype Arg25Arg).

CONCLUSIONS

PFD is useful to improve BCC (Baker Score III/IV) postmammoplasty with no relapse after drug administration. There is also an association between capsular contracture and the presence of homozygous G/G TGF-β1 genotype.

Effects of zafirlukast on capsular contracture: long-term results

Capsular contracture is a distressing complication after breast augmentation for both the patient and surgeon. Although capsular contracture is a multifactorial process, one common denominator in the successful treatment of this complication is believed to be the abatement of inflammation. Leukotriene antagonists have recently emerged as effective prophylactic agents in reactive airway diseases. A prospective study was carried out on 60 female patients (120 prostheses implanted) with mild/severe capsular contracture in at least one breast. The hardness of capsular contracture was assessed by means of the mammary compliance method. Patients received zafirlukast (Accolate&#174;) for a 6-month period. Mammary compliance was assessed at the start of the study and thereafter monthly, during drug intake and for one year after drug withdrawal. The results show a significant decrease in breast compliance values in the first 6 months, followed by a significant increase one year after the end of drug intake. Indeed, zafirlukast-treated patients displayed a 6.93 percent reduction in mammary compliance after 1 month, 14.42 percent after 3 months, 22.05 percent after 6 months and 22.52 percent after 7 months (1 month after the withdrawal of the drug). Thereafter, mammary compliance values gradually increased. A 5.47 percent reduction in mammary compliance was observed 1 year after drug withdrawal. The present study suggests that zafirlukast may be effective in reducing breast capsule distortion in patients with long-standing contracture, though reduced capsular contracture values are strictly related to the duration of drug intake.

Lubricin in human breast tissue expander capsules

Capsular contraction is the most common complication of breast reconstruction surgery. While presence of the contractile protein alpha smooth muscle actin (α-SMA) is considered among the causes of capsular contraction, the exact etiology and pathophysiology is not fully understood. The objective of this study was to investigate the possible role of lubricin in capsular formation and contraction by determining the presence and distribution of the lubricating protein lubricin in human breast tissue expander capsules. Related aims were to evaluate select histopathologic features of the capsules, and the percentage of cells expressing α-SMA, which reflects the myofibroblast phenotype. Capsules from tissue expanders were obtained from eight patients. Lubricin, at the tissue-implant interface, in the extracellular matrix, and in cells, and α-SMA-containing cells were evaluated immunohistochemically. The notable finding was that lubricin was identified in all tissue expander capsules: as a discrete layer at the tissue-implant interface, extracellular, and intracellular. There was a greater amount of lubricin in the extracellular matrix in the intimal-subintimal zone when compared with the tissue away from the implant. Varying degrees of synovial metaplasia were seen at the tissue-implant interface. α-SMA-containing cells were also seen in all but one patient. The findings might help us better understand factors involved in capsule formation.

Oncologic risks of autologous fat grafting to the breast

As the frequency of fat grafting to the breast has increased, some investigators have raised the possibility that this procedure may potentially increase the risks associated with breast cancer. Their concerns included not only interference with cancer detection, but also promotion of tumor formation or recurrence mediated by mechanisms such as aromatase expression, angiogenesis, and tumor stromal cells. However, published clinical studies describing outcomes of fat grafting to the breast in more than 2000 patients have not reported any increase in new or recurrent cancers. The reason for this apparent disconnect may lie in the small sample sizes and relatively short follow-up, but it may also reside in the considerable gap between laboratory studies or theoretical considerations suggesting potential risks and the actual clinical practice. This review discusses potential risks of current and novel approaches to autologous fat grafting to the breast within the context of both the underlying science and clinical practice.

The use of acellular dermal matrix to prevent capsule formation around implants in a primate model

BACKGROUND

Implant-based breast reconstruction is a popular option after mastectomy, but capsular contracture may detract from long-term outcomes. The authors have observed that breast implants covered with acellular dermal matrix (AlloDerm) are less likely to develop a capsule in the area where the implant is in direct contact with the acellular matrix. The authors tested this observation experimentally by comparing capsular formation around implants in the presence and absence of AlloDerm in primates.

METHODS

Eight smooth-surfaced tissue expanders were implanted into eight African green monkeys. In four experimental animals, a sheet of AlloDerm was draped over the tissue expander so as to cover the implant. Four control animals underwent placement of a tissue expander only. Animals were killed after 10 weeks and specimens underwent histologic and immunohistochemical analysis.

RESULTS

Hematoxylin and eosin staining of control specimens revealed the presence of a distinct layer of wavy, parallel arrays of collagen fibers consistent with capsule formation. Immunostaining identified abundant myofibroblasts, a profibrotic cell found in breast capsules. In the AlloDerm-covered specimens, no capsule layer was visible, and specimens stained weakly for myofibroblasts. The difference in myofibroblast staining intensity was statistically significant.

CONCLUSIONS

The use of AlloDerm to partially enclose implants effectively prevented formation of a capsule in areas where AlloDerm contacted the implant at 10 weeks. Long-term studies will be required to determine whether this is a durable result that can be reproduced in humans.

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

Periprosthetic capsular contracture represents a specific iatrogenic phenomenon with different side effects. Recently, interesting data have disclosed a potential role of leukotrienes as important mediators of inflammation in the reactivation process of capsular contracture. Some preliminary studies have assessed the efficacy of leukotriene antagonists in the prevention and treatment of capsular contracture. These clinical data are still lacking of a potential biomolecular basis. The aim of our present study was to evaluate the expression of the protein receptor cysteinyl leukotriene receptors (CysLTR). We included 50 patients with severe capsular contracture (Baker III-IV) and a control group consisting of healthy patients who underwent an implant replacement. In both groups, we performed the protein extraction and semiquantitative analysis for the determination of protein concentration on myofibroblasts and macrophages. Western Blot analysis of protein levels shows a significant increase in the expression of CysLTR in patients with capsular contracture. Our final results show that the increase in the levels of mRNA coding for CysLTR actually translates into an effective increase in protein levels of these mRNA transcripts. These findings could at least partially provide a biomolecular basis that justifies the use of specific antileukotriene drugs in the treatment of this disease.

Effect of tissue inhibitors of metalloproteinases and matrix metalloproteinases on capsular formation around smooth and textured silicone gel implants

BACKGROUND

Capsular contracture is one of the most distressing complications after cosmetic breast augmentation. Evidence suggests that matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) may play a key role in the onset or progression of several fibrotic disorders. In this study we used quantitative reverse-transcription PCR methodology to profile the expression of TIMP-1, TIMP-2, MMP-2, and MMP-9 in the tissue of patients with capsular contracture after breast augmentation with smooth and textured silicone breast implants.

METHODS

The study included 20 female patients (average age = 37 +/- 15 years) with capsular contracture after bilateral subglandular cosmetic breast augmentation with smooth silicone implants. Ten patients developed grade II capsule contracture, 8 grade III contracture, and 1 grade IV contracture. Twenty other female patients (average age = 41 +/- 9 years) with capsular contracture after breast augmentation with textured silicone implants were also included (Baker grade II = 10 patients, grade III = 8, grade IV = 2). Expression of mRNA in capsular tissue was calculated using a relative quantification method (Pfaffl). Statistical analysis was performed using the Mann-Whitney test. The level of significance was considered to be p < 0.05.

RESULTS

The expression of MMP-2 was significantly increased in tissue of patients with textured implants and capsular contracture grades II and III/IV in comparison to grade I (p < 0.05). In comparison to grade I, the capsular tissue from patients with Baker II and III/IV fibrosis showed a significant increase for TIMP-1 and TIMP-2 (p < 0.05) in both smooth and textured silicone implants. The expression was significantly higher in tissue from patients with severe contracture (Baker III/IV) and smooth silicone implants compared with that in tissue from patients with textured implants (p < 0.05).

CONCLUSION

The decrease in MMP-to-TIMP expression can cause increased synthesis and deposition of collagen surrounding alloplastic breast implants, leading to a profibrotic state. The higher expression of TIMPs in capsular tissue of patients with smooth silicone gel implants might be a reason for the observed higher rates of capsular contracture. In the future, a nonoperative treatment that decreases TIMPs but increases the activity of MMPs may be an appropriate therapy for patients with capsular contracture.

Reduction of capsular thickness around silicone breast implants by zafirlukast in rats

Capsular contracture is a very disappointing complication, with an overall incidence between 0.5 and 30% of breast implant operations and, if severe, requiring a further surgical procedure (capsulotomy or capsulectomy). Many frustrating attempts have been made to prevent the fibrotic reaction, mainly with steroids or antibiotics. More recently leukotriene antagonists clinically used in the asthma and lung diseases have been suggested to be potentially useful in counteracting the inflammatory pathway leading to a dense collagen membrane around the prosthesis and thus preventing contracture of the capsule. In this study we evaluated the effectiveness of zafirlukast with the following protocol. Disks of textured implant material were placed dorsally into each of the subcutaneous tissues of 40 rats that were subdivided in 2 groups: 20 rats treated with zafirlukast and 20 controls. At autopsy 77 days after, each implant with its surrounding collagenic tissue was excised, and the macroscopic measure of the membrane thickness was compared with the pathology reports, to definitely assess the foreign body reaction. The mean total thickness of the capsule around the implants was 161.97 microm in the zafirlukast-treated group compared with 345.98 microm in the control group (p < 0.001). Outstandingly, the collagen fibers and fibroblast layer were reduced in the zafirlukast-treated group compared to the controls. Our study confirms the effectiveness of this compound in preventing fibrosis and putatively also in reducing the extent of collagen reaction when a capsule has been formed.

Pirfenidone prevents capsular contracture after mammary implantation

BACKGROUND

Pirfenidone (PFD), a new antifibrotic and antiinflammatory agent, prevents and resolves fibrous tissue. This study evaluated the effect of PFD on adverse events in mammary implants using an animal model. Mammary implantation, the most frequent aesthetic surgery, may present several complications after surgery such as swelling, capsule contracture, hardness, and pain.

METHODS

Wistar rats underwent submammary implantation with either smooth or textured silicone gel implants and were administrated 200 mg/kg of PFD daily. The control group received saline. The animals were killed at 8 weeks. The capsular tissue of both implants was removed for histologic and molecular analyses.

RESULTS

Typical postaugmentation periimplant capsules with opacity on adjacent tissues developed 8 weeks after silicone implantation. No significant differences were observed between the textured and smooth implants in any analyzed parameter. Clearly, PFD reduced capsule thickness around submmamary tissue, fibroblast-like cell proliferation, and recruitment of inflammatory cells. The total cell numbers per field were reduced as well. In contrast, the control group presented abundant mononuclear cell infiltration and fibroblast-like cell proliferation. The total content of collagen in the PFD group was 50% less than in the control group. Fibroblast cells displayed 45% less activated phenotype in the PFD group than in the control group, as determined by immunohistochemistry techniques. In the PFD animals, transforming growth factor-beta (TGF-beta) decreased 85% and collagen 1 gene expression 60%, compared with the control group.

CONCLUSION

The findings show a positive effect of PFD on mammary contracture in 10 rats. Despite the small number of animals, the differences found in 10 control rats encourage the authors to propose a larger study later and to suggest PFD as a potential preventive strategy in human mammary implantation surgery.

Clinical and Morphological Conditions in Capsular Contracture Formed around Silicone Breast Implants

BACKGROUND

A study was performed to investigate histological changes in capsules formed around silicone breast implants and their correlation with the clinical classification of capsular contracture defined by the Baker score. For histological classification, the authors used the classification introduced by Wilflingseder, which identifies four grades of contracture.

METHODS

The study included 24 female patients (average age, 40 +/- 12 years) with capsular contracture after bilateral cosmetic breast augmentation with smooth silicone gel implants (Mentor, Santa Barbara, Calif.). The Baker score was determined preoperatively for each patient. Samples of capsular tissue were obtained from all patients for histologic and immunohistochemical analyses. Capsular thickness, age of the collagen fibers, presence of synovia-like metaplasia on the inner surface of the capsule, number of histiocytes, giant cells, and other inflammatory cells, amount of silicone, foreign body granulomas, and capsule calcification were evaluated.

RESULTS

There was a positive correlation between capsular thickness (p < 0.05) and Baker score. Silicone-containing deposits were found in all four histological capsule types. A trend toward greater capsular thickness was documented in patients with severe inflammatory reaction. These patients also had more clinical symptoms. Greater capsular thickness was associated with a higher number of silicone particles and silicone-loaded macrophages in the peri-implant capsule.

CONCLUSIONS

The authors demonstrated a positive correlation (p < 0.05) between the clinical classification (Baker score I to IV) and the histological classification introduced by Wilflingseder (Wilflingseder score I to IV). An exact histological classification is needed to describe precisely the morphological changes in capsular contracture.

Modification of Cysteinyl Leukotriene Receptor Expression in Capsular Contracture

The development of a fibrotic capsule around foreign material in the body is a physiologic reaction undertaken by the body to protect itself from a material it does not recognize. The periprosthetic capsule can pathologically contract, pressing on the implant; it can cause pain, firmness, and sometimes implant extrusion. The pathogenesis of capsular contracture is still unclear, but most reports indicate a multifactorial explanation. The aim of this study is to investigate the role of cysteinyl leukotriene receptors (cysLTR) on the inflammatory cells involved in the development of the capsular contracture. We recruited 20 patients affected by severe capsular contracture (Baker III-IV) and a control group composed of normal patients who had undergone implant substitution. In both groups, we performed a semiquantitative analysis of mRNA encoding for cysLTR1, cysLTR2, tumor necrosis factor-alpha (TNF-alpha) and interleukin 10 (IL-10) on myofibroblasts and macrophages of the periprosthetic capsular tissue. The molecular analysis showed an increase in the cysLTR2, TNF-alpha gene expression but no change in the cysLTR1 and IL-10 genes in patients affected by capsular contracture. These preliminary findings suggest a primary role for cysteinyl leukotrienes in the activation and up-regulation of capsular contraction mechanisms.

Determination of Serum Fibrosis Indexes in Patients with Capsular Contracture after Augmentation with Smooth Silicone Gel Implants

BACKGROUND

Several studies have confirmed a correlation between the concentration of serum hyaluronan and progressive fibrotic disorders such as liver cirrhosis. The aim of this study was to explore the relationship between serum hyaluronan levels and capsular contracture after aesthetic breast augmentation.

METHODS

The study included 25 female patients (average age, 40 +/- 12 years) with capsular contracture after cosmetic breast augmentation with smooth silicone gel implants (Mentor, Santa Barbara, Calif.). The implants were placed in a submuscular position through an inframammary fold incision. The implant removals were prompted by development of capsular fibrosis (Baker grades I through IV). Samples of capsular tissue were obtained from all patients for standard histologic and immunohistochemical analysis. Blood samples were drawn from all patients immediately before operation. Sera from 20 healthy female patients (average age, 34 +/- 9 years) were used as control.

RESULTS

: Capsular tissue revealed significantly higher thickness in patients with grade III/IV contracture than in women with grade II contracture, according to Baker's classification. There was a moderate (n = 15) or severe (n = 10) chronic inflammatory reaction in the capsules around the implants. Fibroblasts, fibroblast-like cells, and macrophages represented the major cell populations found within the fibrous capsules, along with scattered polymorphonuclear leukocytes, lymphocytes, plasma cells, and mast cells. In addition, activated CD4+ cells were detected. An inner layer with synovia-like metaplasia and multinucleated giant cells was found. There was a significantly higher level (p < 0.05) of hyaluronan serum concentration in patients with capsular contracture (26 +/- 14 microg/liter) compared with control subjects (12 +/- 6 microg/liter). There was a positive correlation between the grade of capsular contracture (Baker grades I through IV) and the hyaluronan serum concentration (Baker grade II, 15 +/- 3 microg/liter; Baker grade III, 34 +/- 13 microg/liter; Baker grade IV, 42 +/- 11 microg/liter) (r = 0.73; p < 0.05).

CONCLUSIONS

Serum hyaluronan levels were significantly elevated in patients with capsular contracture after breast augmentation, and there was a positive correlation with stage of capsular contracture. Further study is necessary to determine whether hyaluronan might be useful as a predictor for the development and progress of capsular fibrosis.

Serologic and histologic findings in patients with capsular contracture after breast augmentation with smooth silicone gel implants: is serum hyaluronan a potential predictor?

BACKGROUND

In this study, breast implant capsular tissues and blood samples from 25 cases were studied to characterize the relationship between capsular findings and serum analysis. The serum fibrosis indexes hyaluronan and the aminoterminal propeptide of procollagen type III (PIIINP) are fairly well correlated in several other studies with the inflammation grade and fibrosis in patients with progressive fibrotic disorders such as liver cirrhosis.

METHODS

The study enrolled 25 female patients (average age, 40 +/- 12 years) with capsular contracture after bilateral cosmetic breast augmentation using smooth silicone gel implants (Mentor). The implants were placed in a submuscular position through an incision in the inframammary fold. The implant removals were prompted by development of capsular fibrosis (Baker grades 1-4). Samples of capsular tissue were obtained from all the patients for standard histologic and immunohistochemical analyses. Blood samples were drawn from all the patients immediately before surgery. Sera from 20 healthy female patients (average age, 34 +/- 9 years) who had undergone plastic surgery for reduction mammaplasty were used as controls.

RESULTS

Histology. Capsular tissue was significantly thicker in patients with grades 3 and 4 contracture than in women with grade 2 contracture according the classification by Baker. There was a moderate (n = 15) or severe (n = 10) chronic inflammatory reaction in the capsules around the implants. Fibroblasts and macrophages represented the major cell population found in the fibrous capsules. In addition, activated CD4+ cells were detected. An inner layer with synovia-like metaplasia and multinucleated giant cells was found. Fibroblast-like cells formed the most common cell type in the capsules, along with macrophages, scattered polymorphonuclear leukocytes, lymphocytes, plasma cells, and mast cells. Serum analysis. There was a significantly higher level (p < 0.05) of hyaluronan serum concentration in patients with capsular contracture (26 +/- 14 microg/l) than in control subjects (12 +/- 6 microg/l). There was a positive correlation between the grade of capsular contracture (Baker 1-4) and the hyaluronan serum concentration (Baker 1-2: 15 +/- 3 microg/l; Baker 3-4: 35 +/- 12 microg/l) (r2 = 0.73; p < 0.05).

CONCLUSION

: In this study, serum hyaluronan levels were significantly elevated in patients with constrictive fibrosis after breast augmentation, and there was a positive correlation with the stage of capsular contracture. Serum hyaluronan concentration may help in defining patients at risk for capsular fibrosis. If treatment with new drugs can be started as a preventive measure, it may be possible to reduce the rate of patients who require surgical intervention.

Biodegradable polydioxanone and poly(l/d)lactide implants: an experimental study on peri-implant tissue response

Several implants for orbital wall fracture treatment are available at the present, but they have drawbacks: resorption, risk for migration and foreign body reaction. Alloplastic resorbable implants would be advantageous: no removal operation and no donor side morbidity. The purpose of this study was to evaluate the foreign body reaction, capsule formation and mechanical properties of two bioresorbable implants. PDS and SR-P(L/DL)LA mesh sheet (70/30) with solid frame (96/4) implants (SR-P(L/DL)LA 70,96) were placed into subcutaneous tissue of 24 rats. Immunohistochemistry was used to evaluate reactivity for Tn-C, alpha-actin, type I and III collagens and two mononuclear cells: T-cells and monocyte/ macrophage. GPC, DSC and SEM were performed. Student's t-test or nonparametric Kruskall-Wallis test were used for statistical analysis. Histology of peri-implant capsule exhibited an inner cell-rich zone and an outer connective tissue zone around both materials. Tn-C reactivity was high in the inner and alpha-actin in the outer zone. At the end of the study, the difference of type I collagen versus type III collagen reactivity in inner zone was statistically significant (P<0.0001) as was the difference of type I collagen versus type III collagen reactivity in outer zone (P<0.0001). Immunohistochemistry did not reveal any statistical differences of T-cell and monocyte/macrophage reactivity around PDS versus SR-P(L/DL)LA 70,96 implants, nor any differences as a function of time. PDS were deformed totally after 2 months. SR-P(L/DL)LA 70,96 implants were only slightly deformed during the follow up of 7 months. PDS degraded rapidly in SEM observation. Particles were detaching from surface. SEM observation revealed that polylactide implant was degrading from the surface and the inner porous core became visible. The degradation came visible at 7 months. There were cracks in perpendicular direction towards to the long axis of the filaments. M(w) of PDS decreased fast compared to the polylactide implant. Foreign body reaction was minimal to both materials but continued throughout the whole observation period. Mechanically PDS was poor, it looses its shape totally within 2 months. It cannot be recommended for orbital wall reconstruction. New mesh sheet-frame structure (SR-P(L/DL)LA 70,96) approved to be mechanically adequate for orbital wall reconstruction. It seems not to possess intrinsic memory and retains its shape. The resorption time is significantly longer compared to PDS and is comparable to other studied P(L/DL)LA copolymers. Thus, the new polylactide copolymer implant may support the orbital contents long enough to give way to bone growth over the wall defect.

Characterization of medroxyprogesterone and DMBA-induced multilineage mammary tumors by gene expression profiling

Mouse mammary tumors arising during medroxyprogesterone-DMBA-mediated mammary carcinogenesis comprised three distinct phenotypes: adenocarcinoma, squamous cell carcinoma, and myoepithelial carcinoma. The molecular signature for each of the three tumor subsets was characterized by gene microarray analysis, and three distinct sets of gene expression profiles were obtained that were corroborated in part by quantitative RT-PCR and immunohistochemistry. These results suggest that this carcinogenesis and gene expression model will be useful for rapidly assessing the histopathological differences arising in mammary carcinogenesis and the effects of tumor promoting or chemoprevention agents.

The effect of seprafilm and interceed on capsule formation around silicone discs in a rat model

The insertion of a foreign substance, such as a breast implant into mammalian soft tissues, evokes a wound healing response that culminates in a dense connective-tissue envelope or capsule surrounding the implant. Several biodegradable products, such as Seprafilm (carboxymethylcellulose and hyaluronic acid) and Interceed (oxidized regenerated cellulose), have been demonstrated to inhibit adhesions in abdominal and gynecologic surgery. The ability of these cellulose compounds to inhibit capsule formation was addressed in this investigation. Twenty-eight rats were implanted intermuscularly with either plain silicone discs (10 animals), discs wrapped in Seprafilm (10 animals), or discs covered with Interceed (8 animals). Additional control animals (6 animals) consisted of two that had sham operations, two animals implanted with Seprafilm only, and two more implanted with Interceed only. Animals were sacrificed in pairs at varying time intervals after implantation (2, 4, 8, 12, and 16 wk), and the tissues around the silicone discs were analyzed with light microscopy. Control animals were sacrificed at 8 wk. Both Interceed and Seprafilm slowed the formation of a capsule around the implanted silicone discs as both products were degraded. Evidence of residual material, presumably Seprafilm and Interceed, was seen intracellularly in animals 3 to 4 mo, respectively, after implantation. However, neither material prevented the eventual formation of a fibrous capsule around the silicone discs. The results of this study suggest that encapsulating foreign substances with these types of biodegradable materials will not significantly hinder capsule formation. A more direct attack on the wound healing mechanism may provide a definitive solution for capsule problems with implanted materials.

Orbital floor reconstruction with poly-L/D-lactide implants: clinical, radiological and immunohistochemical study in sheep

In this study the reconstruction capacity of orbital wall in sheep was evaluated when poly-L/D-lactide (PLDLA96) implants were used for large blow-out defects in 18 sheep. The contralateral side, where the defects healed spontaneously, served as controls. The follow-up was 12, 16, 22 and 36 weeks. Healing was evaluated clinically, radiologically, histologically and immunohistochemically. Physiochemical properties of the implants were also studied. At first, the implants were surrounded by elastic capsules, which gradually ossified. At 36 weeks, 60% were still visible and deformed but surrounded by bone. Light microscopy revealed a low grade inflammatory reaction. Expression of Tn-c and cFn was intense throughout the study. Shear strength decreased gradually and was not measurable after 16 weeks. Crystallinity increased steadily from 1.5 to 29.30% and molecular weight decreased from 49,000 to 4186. In CT, the final bony defect was smaller in the reconstructed sides than in the controls. Based on this study it can be concluded that PLDLA96 implant provokes a local inflammation, which does not prevent bone healing. The deformation of the implant, however, indicates that this PLDLA96 plate is not suitable for orbital floor reconstruction.

Matrix metalloproteinases, tissue inhibitors of metalloproteinases, aminoterminal propeptide of procollagen type III, and hyaluronan in sera and tissue of patients with capsular contracture after augmentation with Trilucent breast implants

In various fibrotic diseases, matrix metalloproteinases (MMPs) and their natural inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), play an important role. In our study, serum concentrations of MMP-1, MMP-2, MMP-9, TIMP-1, and TIMP-2 were determined by enzyme-linked immunosorbent assay in 17 female patients with Baker grade II (n =9), III (n =7), and IV (n =1) capsular contracture after bilateral cosmetic mamma augmentation with Trilucent implants (AEI, Inc., Caversham, United Kingdom). Samples of capsular tissue for standard histology and immunohistochemistry were obtained from all patients. Sera from 20 female patients who had plastic surgery for reduction mammaplasty were used as the control group. The aminoterminal propeptide of procollagen type III (PIIINP) and hyaluronan were analyzed as markers for fibrogenesis in both groups, too. Statistical analysis was performed using the Mann-Whitney test and Spearman rank correlation. Patients with capsular contracture presented significantly higher concentrations of TIMP-1 and TIMP-2 in their sera than did the control group (p < 0.05), which correlated with Baker grade (r = 0.7 versus r = 0.65; p < 0.05). The concentration of MMP-2 was significantly higher in the sera of patients with capsule fibrosis, whereas there were no significant differences in MMP-1, MMP-9, and PIIINP serum concentrations. Patients with capsule fibrosis had a significantly lower MMP-to-TIMP ratio (1.1 +/- 0.4, p <0.05) than the control group (1.5 +/- 0.4), which correlated with the Baker classification (r =0.7; p <0.05). The hyaluronan serum concentration of patients with capsular contracture was significantly higher (p < 0.05) and correlated with the Baker grade (r = 0.73; p < 0.05), whereas PIIINP showed no difference. In the histologic evaluation, there was a chronic inflammatory reaction in the capsules around the breast implants and refracting material within the substance. Immunohistochemically, TIMP-1 and TIMP-2 showed an intensive accumulation, and MMP-2 showed a local reaction. PIIINP could be detected, too, whereas there was no staining for MMP-1 and MMP-9. The elevated systemic MMP-2 concentration and the local positive staining in the tissue might be due to the chronic inflammatory reaction. Nevertheless, the balance between MMPs and their natural inhibitors is disturbed in patients with capsule contracture. The elevated systemic concentration of TIMPs might be a pathway in the pathogenesis of severe fibrosis after breast augmentation with alloplastic material. Hyaluronan might be a useful marker for early prediction of capsule fibrosis, whereas PIIINP is not useful as a predictor.

Nerve growth factor overexpression and autocrine loop in breast cancer cells

We show here that nerve growth factor (NGF), the canonical neurotrophic factor, is synthesized and released by breast cancer cells. High levels of NGF transcript and protein were detected in breast cancer cells by reverse transcription-PCR, Western blotting, ELISA assay and immunohistochemistry. Conversely, NGF production could not be detected in normal breast epithelial cells at either the transcriptional or protein level. Confocal analysis indicated the presence of NGF within classical secretion vesicles. Breast cancer cell-produced NGF was biologically active, as demonstrated by its ability to induce the neuronal differentiation of embryonic neural precursor cells. Importantly, the constitutive growth of breast cancer cells was strongly inhibited by either NGF-neutralizing antibodies or K-252a, a pharmacological inhibitor of NGF receptor TrkA, indicating the existence of an NGF autocrine loop. Together, our data demonstrate the physiological relevance of NGF in breast cancer and its potential interest as a marker and therapeutic target.

The fate of the fibrous capsule after saline implant removal

After removal of a silicone breast implant, if a capsulectomy is not performed, the residual capsule may persist, become calcified, and appear on routine mammograms. The fate of the capsule around saline implants is less clear. The purpose of this study was to determine the fate of the capsule around saline-filled implants in an animal model. Rats were implanted with 6-ml tissue expanders, which were left in place for 4 months. The implants were then removed and the capsules around the injection port (smooth surface) and tissue expander (textured surface) were examined sequentially. The capsules contracted and dissipated gradually over a year in association with a pericapsular vascular proliferation. It may not be necessary to perform a capsulectomy at the time of saline implant removal.

Nerve growth factor stimulates proliferation and survival of human breast cancer cells through two distinct signaling pathways

We show here that the neurotrophin nerve growth factor (NGF), which has been shown to be a mitogen for breast cancer cells, also stimulates cell survival through a distinct signaling pathway. Breast cancer cell lines (MCF-7, T47-D, BT-20, and MDA-MB-231) were found to express both types of NGF receptors: p140(trkA) and p75(NTR). The two other tyrosine kinase receptors for neurotrophins, TrkB and TrkC, were not expressed. The mitogenic effect of NGF on breast cancer cells required the tyrosine kinase activity of p140(trkA) as well as the mitogen-activated protein kinase (MAPK) cascade, but was independent of p75(NTR). In contrast, the anti-apoptotic effect of NGF (studied using the ceramide analogue C2) required p75(NTR) as well as the activation of the transcription factor NF-kB, but neither p140(trkA) nor MAPK was necessary. Other neurotrophins (BDNF, NT-3, NT-4/5) also induced cell survival, although not proliferation, emphasizing the importance of p75(NTR) in NGF-mediated survival. Both the pharmacological NF-kappaB inhibitor SN50, and cell transfection with IkBm, resulted in a diminution of NGF anti-apoptotic effect. These data show that two distinct signaling pathways are required for NGF activity and confirm the roles played by p75(NTR) and NF-kappaB in the activation of the survival pathway in breast cancer cells.

Ultrastructural anatomy of contracted capsules around textured implants in augmented breasts

The development of a capsule around an implant is part of the physiological response to a foreign body. Capsular contracture is the most specific and frustrating complication of augmentation mammaplasty, and a lot of studies have been devoted to it. The aim of the current study is to examine the fine architecture of the contracted capsule around textured implants in humans. Eight capsules from augmented and contracted breasts with gel-filled, textured-surface silicone implants were studied after standard preparation for light and scanning electron microscopy, and after partial digestion in sodium hydroxide. Two capsules from contracted breasts around smooth implants and two noncontracted capsules around textured implants were prepared and studied in the same fashion as controls. A multilayer structure of the contracted capsule was seen, and the architecture of the various layers is described. The inner surface presents irregular craterlike depressions. The arrangement of collagen fibers varies in capsule layers. The effect of a textured-surface implant on the mechanism of capsule contraction based on the observed capsular architecture is that only part of the capsule is effective mechanically in producing a contracting force. A thin vascular layer was identified near the inner surface in contracted capsules around textured implants, and the authors' think that this layer is probably the key structure in the histological development and growth of the capsule.

Time course of transforming growth factor-beta(1) (TGF-beta(1)) mRNA expression in the host reaction to alginate-poly-L-lysine microcapsules following implantations into rat epididymal fat pads

Microencapsulation of islets of Langerhans within semipermeable membranes has been proposed to prevent their immune destruction after transplantation. However, the successful application of this method is impaired by a pericapsular reaction, which eventually induces graft failure. Our goal is to study the role of cytokines in the pathogenesis of this reaction, using the model of alginate-poly-L-lysine microcapsule implantation into Wistar rat epididymal fat pads (EFP). The specific objective of this study was to determine the time course of transforming growth factor (TGF)-beta(1) mRNA expression by semi-quantitative reverse transcriptase-polymerase chain reaction. Microcapsules induced an increase of TGF-beta(1) mRNA expression that reached a maximum 14 days after implantation. Seven, 14, 30, and 60 days after microcapsule implantation, the expression of TGF-beta(1) mRNA was significantly higher in pericapsular infiltrate cells than in nonimplanted EFP cells (p<0.05, p<0.0001, p<0.005, and p<0.01, respectively). Injection of physiological saline induced a small and gradual augmentation of TGF-beta(1) mRNA expression with a maximum 30 days after injection (p<0.01 vs. nonimplanted EFP cells). These results demonstrated that microcapsule implantation, in comparison with saline injection, induce an early, extended, and amplified TGF-beta(1) mRNA expression. This suggests that TGF-beta(1) plays a role in the pathogenesis of the pericapsular host reaction.

New insights in the development of Dupuytren's contracture: a review

Recent advances in the understanding of myofibroblast histology and function, the activity of fibrogenic cytokines, the role of the extracellular matrix and of free radicals are contributing to an understanding of the aetiology of Dupuytren's disease but not yet to its treatment. Surgical excision remains the best treatment.

The immunopathology of siliconosis. History, clinical presentation, and relation to silicosis and the chemistry of silicon and silicone

Recent evidence confirms the fundamental involvement of the human immune system in the reaction to implantation of silicone-based medical devices. An as yet-to-be particularized epitope of many complex substances sharing siloxane structures is presented through the MHC-II apparatus with development and retention of T cell memory. This memory can be tested for in practical terms using one or more forms of silica, which links the immuno-histopathology and autoimmune attributes of "silicosis" with those of "siliconosis." The lesions of siliconosis are typical of those for persistent antigens and delayed, cell mediated hypersensitivity. The basic descriptive pathology of the reaction to silicone has been known since soon after introduction of silicones in medical procedures, with the exception of some details related to the more recent discoveries on the role of cytokines in the immunopathic process. The clinical consequences of siliconosis are common and can be severe in some individuals implanted with silicone devices.