Mixing collagen with fibrin glue to strengthen the sealing effect for pulmonary air leakage

Efficacy of Alaska pollock gelatin sealant for pulmonary air leakage in porcine models

BACKGROUND

Postoperative prolonged air leakage is a frequent complication following lung resection. We have developed a new sealant based on a hydrophobically modified Alaska pollock-derived gelatin (ApGltn) sealant. The purpose of this study was to evaluate the adhesive strength of the ApGltn sealant in comparison with a fibrin sealant using a new spray system in ex vivo and in vivo models.

METHODS

Pleural defects in ex vivo and in vivo porcine models were created, to which the ApGltn sealant or the fibrin sealant was applied. The pressure resistance was assessed with a stepwise increase in airway pressure to confirm air leakage from the sealing site. Tissue samples covered with each sealant were obtained for histologic assessment.

RESULTS

In the ex vivo experiment, the leak pressures of the ApGltn sealant were significantly greater than those of the fibrin sealant (102.94 ± 15.6 cmH₂O and 28.37 ± 5.1 cmH₂O, respectively) (p < 0.01). In the in vivo experiment, the leak pressures of the ApGltn sealant were also significantly greater than those of the fibrin sealant (68.82 ± 18.04 cmH₂O and 43.33 ± 7.13 cmH₂O, respectively) (p = 0.043). The histologic examination confirmed that the ApGltn sealant adhered tightly to both the pleura and the surface of the pleural defect.

CONCLUSIONS

The ApGltn sealant has sufficiently high adhesive quality in ex vivo and in vivo porcine lungs, which could be considered suitable and effective for use in the prevention of air leakage from the lungs.

Type I Collagen-Fibrin Mixed Hydrogels: Preparation, Properties and Biomedical Applications

Type I collagen and fibrin are two essential proteins in tissue regeneration and have been widely used for the design of biomaterials. While they both form hydrogels via fibrillogenesis, they have distinct biochemical features, structural properties and biological functions which make their combination of high interest. A number of protocols to obtain such mixed gels have been described in the literature that differ in the sequence of mixing/addition of the various reagents. Experimental and modelling studies have suggested that such co-gels consist of an interpenetrated structure where the two proteins networks have local interactions only. Evidences have been accumulated that immobilized cells respond not only to the overall structure of the co-gels but can also exhibit responses specific to each of the proteins. Among the many biomedical applications of such type I collagen-fibrin mixed gels, those requiring the co-culture of two cell types with distinct affinity for these proteins, such as vascularization of tissue engineering constructs, appear particularly promising.

Compression-induced structural and mechanical changes of fibrin-collagen composites

Fibrin and collagen as well as their combinations play an important biological role in tissue regeneration and are widely employed in surgery as fleeces or sealants and in bioengineering as tissue scaffolds. Earlier studies demonstrated that fibrin-collagen composite networks displayed improved tensile mechanical properties compared to the isolated protein matrices. Unlike previous studies, here unconfined compression was applied to a fibrin-collagen filamentous polymer composite matrix to study its structural and mechanical responses to compressive deformation. Combining collagen with fibrin resulted in formation of a composite hydrogel exhibiting synergistic mechanical properties compared to the isolated fibrin and collagen matrices. Specifically, the composite matrix revealed a one order of magnitude increase in the shear storage modulus at compressive strains>0.8 in response to compression compared to the mechanical features of individual components. These material enhancements were attributed to the observed structural alterations, such as network density changes, an increase in connectivity along with criss-crossing, and bundling of fibers. In addition, the compressed composite collagen/fibrin networks revealed a non-linear transformation of their viscoelastic properties with softening and stiffening regimes. These transitions were shown to depend on protein concentrations. Namely, a decrease in protein content drastically affected the mechanical response of the networks to compression by shifting the onset of stiffening to higher degrees of compression. Since both natural and artificially composed extracellular matrices experience compression in various (patho)physiological conditions, our results provide new insights into the structural biomechanics of the polymeric composite matrix that can help to create fibrin-collagen sealants, sponges, and tissue scaffolds with tunable and predictable mechanical properties.

Fibrin mechanical properties and their structural origins

Fibrin is a protein polymer that is essential for hemostasis and thrombosis, wound healing, and several other biological functions and pathological conditions that involve extracellular matrix. In addition to molecular and cellular interactions, fibrin mechanics has been recently shown to underlie clot behavior in the highly dynamic intra- and extravascular environments. Fibrin has both elastic and viscous properties. Perhaps the most remarkable rheological feature of the fibrin network is an extremely high elasticity and stability despite very low protein content. Another important mechanical property that is common to many filamentous protein polymers but not other polymers is stiffening occurring in response to shear, tension, or compression. New data has begun to provide a structural basis for the unique mechanical behavior of fibrin that originates from its complex multi-scale hierarchical structure. The mechanical behavior of the whole fibrin gel is governed largely by the properties of single fibers and their ensembles, including changes in fiber orientation, stretching, bending, and buckling. The properties of individual fibrin fibers are determined by the number and packing arrangements of double-stranded half-staggered protofibrils, which still remain poorly understood. It has also been proposed that forced unfolding of sub-molecular structures, including elongation of flexible and relatively unstructured portions of fibrin molecules, can contribute to fibrin deformations. In spite of a great increase in our knowledge of the structural mechanics of fibrin, much about the mechanisms of fibrin's biological functions remains unknown. Fibrin deformability is not only an essential part of the biomechanics of hemostasis and thrombosis, but also a rapidly developing field of bioengineering that uses fibrin as a versatile biomaterial with exceptional and tunable biochemical and mechanical properties.

Techniques in the prevention and management of seromas after breast surgery

Seromas are the most frequent complications following breast surgery, resulting in significant discomfort and morbidity with possible delays in commencing adjuvant therapies. Varied clinical practices exist in the techniques employed to prevent and manage seromata. This article assesses published literature on the techniques employed in prevention of seroma formation following breast surgery, evaluating the different methodologies used. Although prevention is the best strategy, seromata remain problematic and we consider their management. The principle findings were that prevention is key to the management of seromata. Methods employed to prevent seromata include suction drainage, shoulder immobilization, quilting sutures, fibrin sealants and innovative measures of managing the axilla, among others. The evidence demonstrated that a combination of quilting and drains significantly reduces the incidence and volumes of seromata. These effects are sustained by minimizing use of electrocautery, alongside increasing frequencies of axillary sentinel lymph node biopsies and node sampling. The efficacy data on fibrin sealants is inconclusive and consequently should not be routinely used alone or accompanied by quilting sutures. Clinically significant seromas deemed 'symptomatic' by patients and complicating infected seromas should be aspirated. There are limited data on the recommended treatment of established seromas with a paucity of high-quality studies and further research involving randomized trials are indicated.

Treatment of growth plate injury using IGF-I-loaded PLGA scaffolds

Growth plate fracture can lead to retarded growth and unequal limb length, which may have a lifelong effect on a person's physical stature. The goal of this research was to develop an in vivo tissue-engineering approach for the treatment of growth plate injury via localized delivery of insulin-like growth factor I (IGF-I) from cell-free poly(lactic-co-glycolic acid) (PLGA) scaffolds. Mass loss and drug release studies were conducted to study the scaffold degradation and IGF-I release patterns. In vitro cell studies showed that rat bone marrow stromal cells seeded on the porous scaffolds colonized the pores and deposited matrix within the scaffolds. These in vitro evaluations were followed by a proof-of-concept animal study involving implantation of scaffolds in proximal tibial growth plate defects in New Zealand white rabbits. Histological analysis of tissue sections from the in vivo studies showed regeneration of cartilage, albeit with disorganized structure, at the site of implantation of IGF-I-releasing scaffolds; in contrast, only bone was formed in empty defects and those treated with IGF-free scaffolds. The present findings show the potential for treating growth plate injury using in vivo tissue engineering techniques.

The experimental use of N-butyl cyanoacrylate tissue adhesive in pulmonary wedge resections

BACKGROUND

In this experimental study, the effectiveness of N-butyl cyanoacrylate tissue adhesive on preventing air leakage after pulmonary wedge resection was observed.

METHODS

Twenty pairs of sheep lungs were used. Before initiating the study, the sheep lungs were ventilated to identify any air leakage from the parenchyma. On positive results, those sheep lungs were then excluded from the study. Wedge resection was performed on the right and left lower lobes of sheep lungs by clamping the edges forming a triangle of 5 cm × 5 cm × 5 cm. One side of parenchyma was sutured by 3/0 vicryl (Group A) while the other side of parenchyma was sealed by N-butyl cyanoacrylate (Group B). After waiting for 5 min for N-butyl cyanoacrylate to dry, the sheep lungs were intubated by 6F endotracheal tubes. The lungs were soaked in a bath tub filled with 10 cm deep water and inflated by 40 mmHg pressure to record any air leakage from the parenchyma partially sutured by vicryl and sealed by N-butyl cyanoacrylate.

RESULTS

Air leakages were observed on the parenchyma surfaces of group of lungs (100%) sutured by vicryl (minimal 30%, mild 50% or massive 20% levels), while only on four of (20%) the other group of lungs sealed by N-butyl cyanoacrylate, minimal air leakage was observed on the parenchymal surface. There was an extremely significant difference between Group A and Group B in terms of the development of air leakage (p=000).

CONCLUSION

We consider that, N-butyl cyanoacrylate could be used effectively and safely to prevent air leakage from the pulmonary wedge resection surface.

Effectiveness of fibrin adhesive in facial nerve anastomosis in dogs compared with standard microsuturing technique

PURPOSE

Epineural suturing is the most common technique used for peripheral nerve anastomosis. In addition to the foreign body reaction to the suture material, the surgical duration and difficulty of suturing in confined anatomic locations are major problems. We evaluated the effectiveness of fibrin glue as an acceptable alternative for nerve anastomosis in dogs.

METHODS

Eight adult female dogs weighing 18 to 24 kg were used in the present study. The facial nerve was transected bilaterally. On the right side, the facial nerve was subjected to epineural suturing; and on the left side, the nerve was anastomosed using fibrin adhesive. After 16 weeks, the nerve conduction velocity and proportion of the nerve fibers that crossed the anastomosis site were evaluated and compared for the epineural suture (right side) and fibrin glue (left side). The data were analyzed using the paired t test and univariate analysis of variance.

RESULTS

The mean postoperative nerve conduction velocity was 29.87 ± 7.65 m/s and 26.75 ± 3.97 m/s on the right and left side, respectively. No statistically significant difference was found in the postoperative nerve conduction velocity between the 2 techniques (P = .444). The proportion of nerve fibers that crossed the anastomotic site was 71.25% ± 7.59% and 72.25% ± 8.31% on the right and left side, respectively. The histologic evaluation showed no statistically significant difference in the proportion of the nerve fibers that crossed the anastomotic site between the 2 techniques (P = .598).

CONCLUSIONS

The results suggest that the efficacies of epineural suturing and fibrin gluing in peripheral nerve anastomosis are similar.

A prospective randomized trial of the efficacy of marginal quilting sutures and fibrin sealant in reducing the incidence of seromas in the extended latissimus dorsi donor site

BACKGROUND

The extended latissimus dorsi is a workhorse flap and plays an important role in breast reconstruction. Unfortunately, seromas at the flap donor site are a frustrating problem complicating many procedures. The purpose of this study was to evaluate the efficacy of a combination of fibrin sealant (Quixil; Johnson & Johnson, Langhorne, Pa.) and limited quilting sutures at reducing seroma formation.

METHODS

This was a prospective, double-blinded, clinical trial under a single surgeon. Twenty-six patients were enrolled in the study, and all were followed up for a period of 6 months. The patients were randomized to receive either quilting sutures only (group 1) or a combination of Quixil sealant and marginal quilting sutures (group 2).

RESULTS

The incidence of seroma was 23.1 percent in group 1 and 7.7 percent in group 2 (odds ratio, 0.28; relative risk, 0.33). The mean total volume aspirated was significantly higher in group 1 (196.7 ml compared with 30 ml, p = 0.01). The average number of aspirations was 2.7 in group 1 compared with one in group 2. There was a significant reduction in inpatient stay for group 2 by 2 days (p = 0.01). Operative time was shortened by an average of 25 minutes.

CONCLUSIONS

The combination of fibrin sealant and marginal quilting sutures significantly reduces total drainage, hospital stay, and seroma formation. In the authors' opinion, the benefits of seroma prevention outweigh the extra costs associated with this product. The potential, albeit small, risk of virus transmission and allergic reaction, however, needs to be taken into consideration, as with any blood transfusion product.

Surgical sealant for preventing air leaks after pulmonary resections in patients with lung cancer

BACKGROUND

Postoperative air leak is a frequent complication after pulmonary resection for lung cancer. It may cause serious complications, such as empyema, or prolong the need for chest tube and hospitalization. Different types of surgical sealants have been developed to prevent or to reduce postoperative air leaks. A systematic review was therefore undertaken to evaluate the evidence on their effectiveness.

OBJECTIVES

To evaluate the effectiveness of surgical sealants in preventing or reducing postoperative air leaks after pulmonary resection for lung cancer.

SEARCH STRATEGY

We searched the electronic databases MEDLINE (1966 to September 2008), EMBASE (1974 to September 2008), and the Cochrane Central Register of Controlled Trials (CENTRAL)(The Cochrane Library, Issue 3, 2008) and listed references. We hand searched conference proceedings to identify published and unpublished trials.

SELECTION CRITERIA

We included randomized controlled clinical trials in which standard closure techniques plus a sealant were compared with the same intervention with no use of any sealant in patients undergoing elective pulmonary resection provided that a large proportion of the patients studied had undergone pulmonary resection for lung cancer.

DATA COLLECTION AND ANALYSIS

Four reviewers independently selected the trials to be included in the review, assessed methodological quality of each trial and extracted data using a standardized form. Because of several limitations, narrative synthesis was used at this stage.

MAIN RESULTS

Sixteen trials, with 1642 randomized patients in total were included. In thirteen trials there were differences between treatment and control patients in reducing postoperative air leaks. This reduction proved to be significant in six trials. Three trials showed a significant reduction in time to chest drain removal in the treatment group. In two trials, the percentage of patients with persistent air leak was significantly smaller in the treatment group. Finally, three trials including 352 patients showed a statistically significant reduction in length of hospital stay.

AUTHORS' CONCLUSIONS

Surgical sealants reduce postoperative air leaks and time to chest drain removal but this reduction is not always associated with a reduction in length of postoperative hospital stay. Therefore, systematic use of surgical sealants with the objective of reducing hospital stay cannot be recommended at the moment. More and larger randomized controlled clinical trials are needed.

A new fibrin sealant from Crotalus durissus terrificus venom: applications in medicine

Fibrin sealant, a widely available tissue adhesive, has been used since 1940 in a variety of clinical applications. Commercially available fibrin sealant products are synthesized from bovine thrombin and human fibrinogen, which may transmit infectious diseases, and recipients may also develop antibodies against bovine thrombin. Bearing these disadvantages in mind, a new fibrin sealant was developed in 1989 by a group of researchers from the Center for the Study of Venoms and Venomous Animals, in Sao Paulo State, Brazil. The main purpose was to produce an adhesive fibrin without using human blood, to avoid transmitting infectious diseases. The components of this novel sealant were extracted from large animals and a serine proteinase extracted from Crotalus durissus terrificus snake venom. The applicability of this sealant was tested in animals and humans with beneficial results. The new fibrin sealant can be a useful tool clinically due to its flexibility and diversity of applications. This sealant is a biological and biodegradable product that (1) does not produce adverse reactions, (1) contains no human blood, (3) has a good adhesive capacity, (4) gives no transmission of infectious diseases, and (5) may be used as an adjuvant in conventional suture procedures. The effectiveness of this new fibrin sealant is reviewed and its development and employment are described.

Development of new biodegradable hydrogel glue for preventing alveolar air leakage

OBJECTIVE

Air leakage is a frequent complication during lung surgery. A new hydrogel glue was created by mixing aldehyded dextran and epsilon-poly(l-lysine), and its feasibility as a surgical sealant was evaluated in comparison with that of conventional fibrin glue.

METHODS

Bursting pressure after application of each glue to 30 x 30-mm pleuroparenchymal defects was evaluated in two groups of 14 beagle dogs. Biodegradability and histotoxicity of the glues were evaluated in another 6 dogs with 15-mm circular pleuroparenchymal defects. Adhesions, infections, and histologic changes were observed on scheduled days for 6 months.

RESULTS

The mean bursting pressure after application was 38.4 +/- 4.6 cm H2O for the new glue and 32.1 +/- 4.5 cm H2O for fibrin glue (P = .02), the former providing more effective sealing of pulmonary air leakage than the latter. Macroscopically, no adhesions or infections were observed in areas of glue application. About 90% of the new glue degraded within 3 months, but complete disappearance was not observed by 6 months. On the other hand, the fibrin glue was replaced by white pleural tissue at 4 weeks. Histologically, the new glue was covered by one layer of mesothelial cells at 2 weeks and completely covered by thick fibrous tissue at 4 weeks. Inflammatory reaction was minimal around the residual glue after 3 months. Although the new glue degraded more slowly than did the fibrin glue, the biocompatibility of the new glue was sufficient for clinical use.

CONCLUSION

Our new hydrogel glue demonstrates a strong sealing effect, with good biocompatibility, and has potential usefulness as an adhesive in lung surgery.

Creation of a uniform pleural defect model for the study of lung sealants

OBJECTIVE

Animal models are indispensable for the development of new therapeutic methods for the closure of alveolar air leakage. However, it is difficult to create a uniform pleural defect model. The purpose of this study was to establish an appropriate animal model for assessing the efficacy and histotoxicity of synthetic sealants for lung surgery.

METHODS

Nine beagle dogs were used to evaluate the pleural defect model in comparison with conventional resection procedures. A donut-shaped silicon ring with an inner diameter of 15 mm was placed on the pleura, and 0.1 mL of cyanoacrylate was dropped into the ring. A pleural defect was created by sliding a microtome blade just beneath the polymerized cyanoacrylate. Hemostasis was performed by pressure with a sponge.

RESULTS

Morphologically, round areas of the pleura were uniformly resected with our procedure. The resected tissue consisted of pleura and thin underlying lung parenchyma. Among the results from 3 surgeons, there were no significant differences in the mean time required for hemostasis (P = .69), the mean thickness of the resected tissue (P = .13), and the mean amount of air leakage from the resected area (P = .19). No penetration of cyanoacrylate into the lung parenchyma was evidenced by immunofluorescence microscopy. Histologically, when the pleura was resected without using cyanoacrylate, a thick fibrocellular layer extended to the lung parenchyma. Furthermore, severe fibrosis was observed when electrocautery was used for hemostasis. However, when the pleura was resected using cyanoacrylate, the normal alveolar structure was preserved.

CONCLUSIONS

Our uniform pleural defect model using cyanoacrylate may be feasible for the evaluation of synthetic sealants for alveolar air leakage.

Diffuse bullous emphysema of the lung: conservative resection with a local application of a biological glue

A middle-aged man suffered a recurrent right pneumothorax with a prolonged air leak due to diffuse bullous emphysema of the lung. On December 19, 2001, he underwent a successful conservative resection of the bullae with a local application of a gelatin-resorcin-formalin biological glue.

Preventing Seroma in the Latissimus Dorsi Flap Donor Site With Fibrin Sealant

Donor site seroma continues to be the most common complication of latissimus dorsi flap reconstruction. Numerous preventive methods and treatments have been described. The use of fibrin sealant in the donor site before closure may be an effective means of seroma prevention. The authors evaluated the efficacy of fibrin sealant in conjunction with closed suction drainage in a series of 17 latissimus flap donor sites. They also determined their approximate institutional seroma rate with a retrospective chart review of 20 donor sites. The fibrin sealant patients had a seroma rate of 11.8% compared with a rate of 35% among the untreated patients (P = 0.047). This compares favorably with seroma rates as high as 79% described in the literature. In conclusion, the use of fibrin sealant in the latissimus flap donor site appears to be effective in preventing seroma.

The use of fibrin glue in skin grafts and tissue-engineered skin replacements: a review

Fibrin glue has been widely used as an adhesive in plastic and reconstructive surgery. This article reviews the advantages and disadvantages of its use with skin grafts and tissue-engineered skin substitutes. Fibrin glue has been shown to improve the percentage of skin graft take, especially when associated with difficult grafting sites or sites associated with unavoidable movement. Evidence also suggests improved hemostasis and a protective effect resulting in reduced bacterial infection. Fibrin, associated with fibronectin, has been shown to support keratinocyte and fibroblast growth both in vitro and in vivo, and may enhance cellular motility in the wound. When used as a delivery system for cultured keratinocytes and fibroblasts, fibrin glue may provide similar advantages to those proven with conventional skin grafts. Fibrin glue has also been shown to be a suitable delivery vehicle for exogenous growth factors that may in the future be used to accelerate wound healing.