Effect of amniotic fluid on peri-implant capsular formation

The effects of human amniotic membrane on silicone related capsule formation in rats

Silicone breast implants are commonly used materials in plastic surgery for breast augmentation and reconstruction and the most severe complication of silicone implants are capsule contraction which occurs in 40% of patients. The aim of our study is to evaluate how the amniotic membrane alters the capsule formation effects of silicone 24 wistar rats were used in the study. We placed a bare silicone block into the left side (Subgroup A) and single layer amniotic membrane coated silicone block into the right side (Subgroup B) of the rats back. The rats were then separated into three groups and in group 1 rats were euthanized after 3 weeks, in group 2 after 12 weeks and in group 3 after 24 weeks. Then capsule thickness, fibroblast and lymphocyte cell counts were evaluated for each sample. In Group 2 and group 3, the capsule thickness in Subgroup B was detected to be statistically significantly lower than that in Subgroup A. In Group 1, 2, and 3, the lymphocyte count in the capsule tissue taken from Subgroup B was lower than Subgroup A but the difference was not statistically significant. In Group 2 and 3, the fibrocyte count detected in the capsule tissue in Subgroup B was found to be statistically significantly lower than Subgroup A. the amniotic membrane was demonstrated to reduce capsule thickness by the antifibrinolytic effect in our study.

Effects of Different Concentrations of Injectable Collagenase Enzyme on Capsular Tissue Around Silicone Implants: A Preliminary Experimental Study for the Development of a New Treatment Strategy

OBJECTIVES

In recent studies, collagen organization was blamed for the formation of capsular contracture which is still a challenging problem after silicone implant-based breast operations. In this study, effects of different concentrations of collagenase enzyme derived from Clostridium histolyticum on the capsular tissue formation around the silicone implants were investigated. The injectable form of collagenase has a routine clinical use in the treatment of both Dupuytren's and Peyronie's diseases.

MATERIALS AND METHODS

Thirty-two Wistar albino rats were randomized into four groups. A 2 × 1 × 0.3-cm-sized silicone block was inserted inside a dorsal subcutaneous pocket in all groups. After 2 months of insertion, capsule thicknesses around the implants were detected under ultrasonography. This was followed by injection of isotonic saline, 150, 300, and 600 IU in Gr-1, 2, 3, and 4, respectively. All the animals were sacrificed at the end of the first week for histologic sampling to determine fibroblast proliferation, vessel density of the tissue, necrosis, edema, inflammation, and capsule thickness. All the data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests and compared for significance of the results.

RESULTS

There was no significant difference in terms of capsule thinning between the 300 and 600 IU groups but in both groups thinning was significantly higher than the sham group. In the 150 IU group there was no significant thinning as compared to the sham group (p > 0.05). However, complications such as skin necrosis, infection, and seroma formation were seen only in the 600 IU injection group. The optimal safe and effective dose of the enzyme was accepted as 300 IU. The 300 IU injection provided up to 89 % thinning in the capsule tissue. There was thinning of the collagen bundles parallel to capsule thickness. In the 600 IU group, micro-pores were encountered at the thinnest points.

CONCLUSION

However, the late results and recurrence rates of capsular contracture were not included in this study; collagenase seemed effective for the reduction of capsular tissue around the implants.

NO LEVEL ASSIGNED

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Biomedical implant capsule formation: lessons learned and the road ahead

Clinicians and investigators have been implanting biomedical devices into patients and experimental animals for centuries. There is a characteristic complex inflammatory response to the presence of the biomedical device with diverse cell signaling, followed by migration of fibroblasts to the implant surface and the eventual walling off of the implant in a collagen capsule. If the device is to interact with the surrounding tissues, the collagen envelope will eventually incapacitate the device or myofibroblasts can cause capsular contracture with resulting distortion, migration, or firmness. This review analyzes the various tactics used in the past to modify or control capsule formation with suggestions for future investigative approaches.

Effects of coagulase-negative staphylococci and fibrin on breast capsule formation in a rabbit model

BACKGROUND

The etiology and ideal clinical treatment of capsular contracture (CC) remain unresolved. Bacteria, especially coagulase-negative staphylococci, have been previously shown to accelerate the onset of CC. The role of fibrin in capsule formation has also been controversial.

OBJECTIVE

The authors investigate whether fibrin and coagulase-negative staphylococci (CoNS) modulate the histological, microbiological, and clinical outcomes of breast implant capsule formation in a rabbit model and evaluate contamination during the surgical procedure.

METHODS

Thirty-one New Zealand white female rabbits were each implanted with one tissue expander and two breast implants. The rabbits received (1) untreated implants and expanders (control; n = 10), (2) two implants sprayed with 2 mL of fibrin and one expander sprayed with 0.5 mL of fibrin (fibrin; n = 11), or (3) two implants inoculated with 100 µL of a CoNS suspension (10(8)CFU/mL-0.5 density on the McFarland scale) and one expander inoculated with a CoNS suspension of 2.5 × 10(7) CFU/mL (CoNS; n = 10). Pressure/volume curves and histological and microbiological evaluations were performed. Operating room air samples and contact skin samples were collected for microbiological evaluation. The rabbits were euthanized at four weeks.

RESULTS

In the fibrin group, significantly decreased intracapsular pressures, thinner capsules, loose/dense (<25%) connective tissue, and negative/mild angiogenesis were observed. In the CoNS group, increased capsular thicknesses and polymorph-type inflammatory cells were the most common findings. Similar bacteria in capsules, implants, and skin were cultured from all the study groups. One Baker grade IV contracture was observed in an implant infected with Micrococcus spp.

CONCLUSIONS

Fibrin was associated with reduced capsule formation in this preclinical animal model, which makes fibrin an attractive potential therapeutic agent in women undergoing breast augmentation procedures. Clinical strategies for preventing bacterial contamination during surgery are crucial, as low pathogenic agents may promote CC.

Effects of fibrin, thrombin, and blood on breast capsule formation in a preclinical model

BACKGROUND

The root cause of capsular contracture (CC) associated with breast implants is unknown. Recent evidence points to the possible role of fibrin and bacteria in CC formation.

OBJECTIVES

The authors sought to determine whether fibrin, thrombin, and blood modulated the histological and microbiological outcomes of breast implant capsule formation in a rabbit model.

METHODS

The authors carried out a case-control study to assess the influence of fibrin, thrombin, and blood on capsule wound healing in a rabbit model. Eighteen New Zealand white rabbits received four tissue expanders. One expander acted as a control, whereas the other expander pockets received one of the following: fibrin glue, rabbit blood, or thrombin sealant. Intracapsular pressure/volume curves were compared among the groups, and histological and microbiological evaluations were performed (capsules, tissue expanders, rabbit skin, and air). The rabbits were euthanized at two or four weeks.

RESULTS

At four weeks, the fibrin and thrombin expanders demonstrated significantly decreased intracapsular pressure compared to the control group. In the control and fibrin groups, mixed inflammation correlated with decreased intracapsular pressure, whereas mononuclear inflammation correlated with increased intracapsular pressure. The predominant isolate in the capsules, tissue expanders, and rabbit skin was coagulase-negative staphylococci. For fibrin and thrombin, both cultures that showed an organism other than staphylococci and cultures that were negative were associated with decreased intracapsular pressure, whereas cultures positive for staphylococci were associated with increased intracapsular pressure.

CONCLUSIONS

Fibrin application during breast implantation may reduce rates of CC, but the presence of staphylococci is associated with increased capsule pressure even in the presence of fibrin, so care should be taken to avoid bacterial contamination.

Efficacy of antiadhesion barrier solution on periimplant capsule formation in a white rat model

Antiadhesive barrier solution (AABS) has been proven to prevent intraabdominal adhesion by reducing inflammation and fibrosis formation. Because this mechanism can also be applied to capsule formation after the breast implant insertion, we hypothesize that AABS can reduce capsular contraction and evaluate the efficacy of AABS on perisilastic implant capsule formation after submuscular insertion. A silicone block was inserted beneath the panniculus carnosus muscle in 10 rats. The experiment group received 0.1 mL of AABS (Guardix, Hanmi Medical Co.) instilled into the pocket, whereas the control group received 0.1 mL saline solution. Periimplant capsules were excised after 4 weeks and were evaluated for inflammatory cell count, capsular thickness, collagen pattern, and amount of myofibroblast. The inflammatory cell count and the capsular thickness were lower in the experiment group than in the control group (P < 0.05). The collagen pattern was loose and parallel in the experiment group, and the amount of myofibroblast was much less compared with the control group. AABS reduced the amount of inflammatory cells, myofibroblast, and capsular thickness. It also made the collagen fibers in the capsule loose and parallel. Therefore, AABS seemed to be effective in reducing the periimplant capsule formation.

Hyaluronan modulates pro-inflammatory immune activity in the mid-trimester amniotic cavity

Hyaluronan (HA), which comprises repeating disaccharides of D-glucuronic acid and N-acetyl-glucosamine, is a component of the extracellular matrix. In response to infection or tissue injury HA is released into the extracellular milieu where it modulates immune activity. We hypothesized that HA is present in mid-trimester amniotic fluid and contributes to immune regulation at that site. Amniotic fluid from 392 women undergoing a mid-trimester amniocentesis were tested for HA by ELISA. Amniotic fluids from 41 women were also cultured ex vivo in the presence or absence of lipopolysaccharide (LPS). Supernatants were collected after 24h and tested for tumor necrosis factor-alpha (TNFalpha) and interleukin (IL)-10 by ELISA. Clinical parameters were obtained after completion of laboratory testing. All amniotic fluids were positive for HA. The median (range) concentration was 3.2 (0.6-91.7) microg/mg amniotic fluid protein. Women with at least 2 prior pregnancies and a history of > or =2 spontaneous abortions had a higher median HA concentration than did previously pregnant women with 0-1 prior abortions. Women who conceived following in vitro fertilization also had an elevated median amniotic fluid HA compared to women with spontaneous conceptions. Both endogenous and LPS-induced TNFalpha production by ex vivo cultured amniotic fluid cells, but not IL-10 production, was inversely proportional to the amniotic fluid HA concentration. In conclusion, intraamniotic HA levels are elevated in pregnancies at risk for adverse outcome and HA may be a component of the fetal response to immune alterations that threaten gestation.

Effect of verapamil on reduction of peri-implant capsular thickness

Silicone is a material commonly used in reconstructive and aesthetic surgery, but capsular formation is a very frequent complication of silicone implants. This study aimed to investigate whether verapamil, a calcium-channel blocker, can reduce the thickness of the peri-implant capsule in rats when it is instilled into the subcutaneous pockets. For this study, 60 female Wistar albino rats were used, and cubes of silicone blocks (10 x 10 x 5 mm) were crafted. The rats were divided into five groups of 12 each, and the groups were distinguished according to the use of silicone and artificially created hematoma relevant to administration of a single dose of 5 mg verapamil (Isoptin). The control group was left without silicone. In two of the four silicone groups, hematoma was artificially created around the silicone by a 1-ml injection of blood. The implants were removed 6 months later, and capsulectomy was performed. Under light microscopic examination, no severe inflammation was observed in any of the capsule tissues. Additionally, the thickness of the capsule was measured and found to be significantly reduced statistically in all the verapamil-treated groups, including the groups with the artificially created hematoma. In conclusion, based on the statistically significant data obtained in this study, subcutaneous verapamil administration may be a useful adjunct for preventing formation of capsular contracture after silicone implantations. This preliminary work in rats should be confirmed with larger mammals before carefully controlled clinical trials are considered.

Zafirlukast pocket delivery impairs the capsule healing around textured implants in rats

BACKGROUND

The aim of this study was to investigate the effects of zafirlukast on capsule thickness, collagen fiber density, and myofibroblast cell count of the healing tissue around silicone textured implants in rats.

METHODS

Thirty-six male Wistar rats were divided (n = 18) into two groups. In one group, two parallel incisions (1.5 cm long) were made into the right and left sides of the spine. Two pockets were then created in which shell-shaped textured implants were inserted. The left-side pocket was injected with 0.2 ml of saline solution (SSG) and the right-side pocket with a dose of 1.25 mg/kg of zafirlukast (ZLG). The other 18 rats (sham, SG) had only one pocket created, followed by the placement of an implant and injection of 0.2 ml of saline solution. The rats were euthanized on the 7th, 35th, or 90th days followed by careful dissection of the implant. The capsules and peri-implant tissues were prepared for histologic analysis. An ANOVA test and Tukey test were applied (p < 0.05).

RESULTS

ZL was effective in impairing the capsule thickness on the 35th and 90th days compared to the other two groups (sham and saline). Not only was it effective in impairing the collagen density on the 35th and 90th days, but it also showed the same effect in the SSG (systemic); fewer myofibroblasts were counted on the 90th day in the ZLG compared to the SG group; the number of myofibroblasts was significantly lower in the ZLG than in the SSG.

CONCLUSIONS

Pocket delivery of one dose of Zafirlukast was effective in impairing capsule formation around the textured implant.

Flector tissugel used to treat capsular contracture after breast augmentation surgery

Capsular contracture constitutes the main postoperative complication after breast augmentation by implant placement. To date, no systemic treatment known allows for improvement that does not simultaneously put the patient at risk for secondary complications of a more general nature. Flector Tissugel is the sole locally active antiinflammatory patch. Its durable local antiinflammatory effect is associated only with a risk for rare and highly limited side effects. After approximately 3 weeks of treatment, a high frequency of change from capsular contracture Baker 2 or 3 to Baker 1 occurs, provided the application was started no later than 3 months after the onset of capsular contracture.

Voies de recherche pour la mise au point de nouvelles prothèses mammaires

Despite the improvement of breast implant quality across the last decade, the perfect implant does not exist. Therefore research should manage to improve those implants. In this article we have tried to identify different directions to investigate for better prosthesis: improvement of the shell, the filling and the form. Moreover, other targets as fat transfer or other permanent soft tissue filler also need further experimental and clinical investigation.