Clinical applications of fibrin sealants

Natural Polymer-Polyphenol Bioadhesive Coacervate with Stable Wet Adhesion, Antibacterial Activity, and On-Demand Detachment

Medical adhesives are emerging as an important clinical tool as adjuvants for sutures and staples in wound closure and healing and in the achievement of hemostasis. However, clinical adhesives combining cytocompatibility, as well as strong and stable adhesion in physiological conditions, are still in demand. Herein, a mussel-inspired strategy is explored to produce adhesive coacervates using tannic acid (TA) and methacrylate pullulan (PUL-MA). TA|PUL-MA coacervates mainly comprise van der Waals forces and hydrophobic interactions. The methacrylic groups in the PUL backbone increase the number of interactions in the adhesives matrix, resulting in enhanced cohesion and adhesion strength (72.7 Jm-2), compared to the non-methacrylated coacervate. The adhesive properties are kept in physiologic-mimetic solutions (72.8 Jm-2) for 72 h. The photopolymerization of TA|PUL-MA enables the on-demand detachment of the adhesive. The poor cytocompatibility associated with the use of phenolic groups is here circumvented by mixing reactive oxygen species-degrading enzyme in the adhesive coacervate. This addition does not hamper the adhesive character of the materials, nor their anti-microbial or hemostatic properties. This affordable and straightforward methodology, together with the tailorable adhesivity even in wet environments, high cytocompatibility, and anti-bacterial activity, enables foresee TA|PUL-MA as a promising ready-to-use bioadhesive for biomedical applications.

Retinoic acid/calcite micro-carriers inserted in fibrin scaffolds modulate neuronal cell differentiation

The controlled release of cell differentiating agents is crucial in many aspects of regenerative medicine. Here we propose the use of hybrid calcite single crystals as micro-carriers for the controlled and localized release of retinoic acid, which is entrapped within the crystalline lattice. The release of retinoic acid occurs only in the proximity of stem cells, upon dissolution of the calcite hybrid crystals that are dispersed in the fibrin scaffold. These hybrid crystals provide a sustained dosage of the entrapped agent. The environment provided by this composite scaffold enables differentiation towards neuronal cells that form a three-dimensional neuronal network.

Intraoperative injection of combined fibrin sealant and methylene blue dye for surgery of branchial cleft cysts: A case report

Differential diagnosis of a lateral neck mass, especially in paediatric patients, should include branchial cleft cysts (BrCC). It is often difficult to identify and completely resect all cystic components, especially when the lesion becomes infected and/or gigantic. Incomplete excision increases the likelihood of recurrences. We reported a simple technique to facilitate the BrCC resection. Tisseel fibrin glue (FG: Baxter AG, Vienna, Austria) was mixed with methylene blue dye in inverse portion to the cyst size and/or the FG volume before injecting into the cystic lumen. After polymerisation of the dyed glue, the lesion was better visualised and extirpated in toto with the aid of the dye colour and gelatinisation by FG. An up-to-date diagnostic and therapeutic algorithm for BrCC was also presented.

Incorporation of Collagen and Hyaluronic Acid to Enhance the Bioactivity of Fibrin-Based Hydrogels for Nucleus Pulposus Regeneration

Hydrogels, such as fibrin, offer a promising delivery vehicle to introduce cells into the intervertebral disc (IVD) to regenerate damaged disc tissue as a potential treatment for low back pain. However, fibrin lacks key extracellular matrix (ECM) components, such as collagen (Col) and hyaluronan (HA), normally found in native nucleus pulposus (NP) tissue. The overall aim of this work was to create a fibrin-based hydrogel, by incorporating Col and HA into the matrix to enhance NP-like matrix accumulation using articular chondrocytes (CC). Firstly, we assessed the effect of fibrin concentrations on hydrogel stability, and the viability and proliferation kinetics of articular chondrocytes. Secondly, we investigated the effect of incorporating Col and HA to enhance NP-like matrix accumulation, and finally, examined the influence of various HA concentrations. Results showed that increasing fibrin concentration enhanced cell viability and proliferation. Interestingly, incorporation of HA promoted sGAG accumulation and tended to suppress collagen formation at higher concentrations. Taken together, these results suggest that incorporation of ECM components can enhance the bioactivity of fibrin-based hydrogels, which may help advance the clinical potential of commercial cell and biomaterial ventures in the treatment of IVD regeneration.

Advancing biomaterials of human origin for tissue engineering

Biomaterials have played an increasingly prominent role in the success of biomedical devices and in the development of tissue engineering, which seeks to unlock the regenerative potential innate to human tissues/organs in a state of deterioration and to restore or reestablish normal bodily function. Advances in our understanding of regenerative biomaterials and their roles in new tissue formation can potentially open a new frontier in the fast-growing field of regenerative medicine. Taking inspiration from the role and multi-component construction of native extracellular matrices (ECMs) for cell accommodation, the synthetic biomaterials produced today routinely incorporate biologically active components to define an artificial in vivo milieu with complex and dynamic interactions that foster and regulate stem cells, similar to the events occurring in a natural cellular microenvironment. The range and degree of biomaterial sophistication have also dramatically increased as more knowledge has accumulated through materials science, matrix biology and tissue engineering. However, achieving clinical translation and commercial success requires regenerative biomaterials to be not only efficacious and safe but also cost-effective and convenient for use and production. Utilizing biomaterials of human origin as building blocks for therapeutic purposes has provided a facilitated approach that closely mimics the critical aspects of natural tissue with regard to its physical and chemical properties for the orchestration of wound healing and tissue regeneration. In addition to directly using tissue transfers and transplants for repair, new applications of human-derived biomaterials are now focusing on the use of naturally occurring biomacromolecules, decellularized ECM scaffolds and autologous preparations rich in growth factors/non-expanded stem cells to either target acceleration/magnification of the body's own repair capacity or use nature's paradigms to create new tissues for restoration. In particular, there is increasing interest in separating ECMs into simplified functional domains and/or biopolymeric assemblies so that these components/constituents can be discretely exploited and manipulated for the production of bioscaffolds and new biomimetic biomaterials. Here, following an overview of tissue auto-/allo-transplantation, we discuss the recent trends and advances as well as the challenges and future directions in the evolution and application of human-derived biomaterials for reconstructive surgery and tissue engineering. In particular, we focus on an exploration of the structural, mechanical, biochemical and biological information present in native human tissue for bioengineering applications and to provide inspiration for the design of future biomaterials.

In vivo study of novelly formulated porcine-derived fibrinogen as an efficient sealant

Fibrinogen has been used as surgical sealant in the clinical setting for decades. The application of human plasma-derived fibrinogen is limited due to high cost and the risk of prion and virus infection. We developed a novel arginine-formulated fibrinogen from cryoprecipitates of porcine plasma. This porcine-derived fibrinogen exhibited excellent stability during sterilization and better hemostatic efficacy than a leading commercial hemostatic product in a nonlethal hemorrhage model. Therefore, it has the potential to be more economical and readily available while having a decreased risk of human blood-borne pathogen transmission.

Single and dual crosslinked oxidized methacrylated alginate/PEG hydrogels for bioadhesive applications

A degradable, cytocompatible bioadhesive can facilitate surgical procedures and minimize patient pain and post-surgical complications. In this study a bioadhesive hydrogel system based on oxidized methacrylated alginate/8-arm poly(ethylene glycol) amine (OMA/PEG) has been developed, and the bioadhesive characteristics of the crosslinked OMA/PEG hydrogels evaluated. Here we demonstrate that the swelling behavior, degradation profiles, and storage moduli of crosslinked OMA/PEG hydrogels are tunable by varying the degree of alginate oxidation. The crosslinked OMA/PEG hydrogels exhibit cytocompatibility when cultured with human bone marrow-derived mesenchymal stem cells. In addition, the adhesion strength of these hydrogels, controllable by varying the alginate oxidation level and measured using a porcine skin model, is superior to commercially available fibrin glue. This OMA/PEG hydrogel system with controllable biodegradation and mechanical properties and adhesion strength may be a promising bioadhesive for clinical use in biomedical applications, such as drug delivery, wound closure and healing, biomedical device implantation, and tissue engineering.

A double blind study on the efficacy of local application of hemocoagulase solution in wound healing

AIM

The present double blind study has been designed to evaluate the efficacy of local application of hemocoagulase solution as compared to a placebo in wound healing following dental extraction.

MATERIALS AND METHODS

A total of 20 patients who required dental extraction for orthodontic intervention were included. The hemocoagulase solution and a placebo were locally applied to the extraction sockets and the efficacy of the solution in terms of bleeding control, anti-inflammatory responses, its antiseptic properties and efficacy in wound healing were evaluated.

RESULTS

The mean time required to achieve hemostasis was found to be 1.37 minutes in side A (test) and 2.33 minutes in side B (control) indicating that side A achieved faster hemostasis when compared to side B. At the 6th hour postoperatively, bleeding was not evident on either sides, and the amount of pain in side A was found to be less compared to side B. The number of RBCs, polymorphs, chronic inflammatory cells were not different in both the groups, whereas at 3rd postoperative day epithelial cells were greater in side A (test) compared to side B (control). Biopsy reports on the 12th postoperative day indicated that the number of fibroblasts, epithelial cells, collagen count was found to be greater in side A (test) compared to side B (control).

CONCLUSION

The topical hemocoagulase solution may be advocated in the field of oral and maxillofacial surgery, as a hemostatic agent and promoter of wound healing. However, further studies, with large number of cases and different clinical situations should be considered to authenticate the efficacy of this hemocoagulase solution in the practice of oral and maxillofacial surgery.

CLINICAL SIGNIFICANCE

Wound healing plays an important role in the success of any surgical procedure, such as extractions, and the hemocoagulase system may act as a hemostatic agent and a promoter of wound healing.

Hemostatic agents

Hemostasis is an integral and very important aspect of surgical practice. As a rule, most bleeding from dental surgery can be controlled by pressure. When the application of pressure does not yield satisfactory results, or where more effective hemostasis is required, hemostatic agents are used. These agents act to stop bleeding either mechanically or by augmenting the coagulation cascade. Some of the newer agents that are available to the dental profession have been presented.

Traumatic dislocation of the incudostapedial joint repaired with fibrin tissue adhesive

We present a case of traumatic dislocation of the incudostapedial joint (ISJ) and a simple method for controlled application of the glue using commercial fibrin tissue adhesive. A 26-year-old female presented to our ENT clinic for hearing impairment to her left ear 2 months after a head trauma due to a motorcycle accident. The audiogram revealed a 40- to 50-dB HL conductive hearing loss with a notch configuration in bone conduction curve on the left ear. Computed tomography of the left temporal bone revealed a longitudinal fracture line. An exploratory tympanotomy was performed under general anesthesia. The ISJ was found dislocated while the incus was trapped by the edges of the bony lateral attic wall fracture. A small bony edge that impeded incus movement was removed and a small amount of the glue was precisely applied to the lenticular process of the incus with an angled incision knife. The long process of the incus was firmly pressed over the stapes for 30 seconds with a 90° hook and 60 seconds after the application of the glue the ISJ was repaired. One year after our patient achieved full airbone gap (ABG) closure (ABG, ≤10 dB HL), while she demonstrated overclosure in frequencies 2 and 4 kHz. Fibrin tissue glue allowed safe, rapid, and accurate repair of the ISJ and resulted in an anatomically normal articulation as the mass and shape of the ossicles was preserved. Moreover, our patient achieved full ABG closure.

The use of fibrin glue in surgery of the knee

Fibrin glue, also known as fibrin sealant, is now established as a haemostatic agent in surgery, but its role in orthopaedic surgery is neither well known nor clearly defined. Although it was originally used over 100 years ago, concerns about transmission of disease meant that it fell from favour. It is also available as a slow-release drug delivery system and as a substrate for cellular growth and tissue engineering. Consequently, it has the potential to be used in a number of ways in orthopaedic surgery. The purpose of this review is to address its use in surgery of the knee in which it appears to offer great promise.

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.

Renal injury and the application of polysaccharide hemospheres: a laparoscopic experimental model

BACKGROUND AND PURPOSE

Microporous polysaccharide hemospheres (MPH) are hemostatic beads engineered from purified plant starch. MPH accelerates the natural clotting cascade by concentrating clotting factors and proteins on their surface while absorbing aqueous and low molecular weight components from blood. The purpose of this study was to determine the efficacy of MPH in achieving hemostasis in the setting of laparoscopic renal injury.

MATERIALS AND METHODS

In four domestic pigs, 16 laparoscopic renal trocar injuries were created (8 each of 12 and 5 mm). A standard hand-assisted laparoscopic approach was used to each kidney so that two lesions per kidney were randomly created. MPH was applied to each treatment lesion with light pressure maintained for 60 seconds. Four of the 16 lesions, two each of 12 and 5 mm, were allowed to bleed as controls. Hemostasis was defined as no active bleeding or oozing. The animals were sacrificed at the conclusion of the procedure.

RESULTS

The mean time to hemostasis for the 12-mm MPH and control lesions was 196.2 +/- 53.3 and 372.0 +/- 225.6 seconds, while the average blood loss was 8.3 +/- 3.7 and 12.0 +/- 4.9 g, respectively. For the 5-mm MPH and control lesions, the average time to hemostasis was 100.2 +/- 24.8 and 247.0 +/- 134.4 seconds, while the average blood loss was 8.3 +/- 3.8 and 9.0 +/- 0.7 g, respectively. The median number of applications of the MPH for the 5- and 12-mm injuries was 1 and 2, respectively.

CONCLUSIONS

MPH provided a rapid and effective means of hemostasis for laparoscopic renal parenchymal injuries in this model. Additional evaluation is warranted, however, before general application is advisable.

Cryoprecipitate use in 25 Canadian hospitals: commonly used outside of the published guidelines

BACKGROUND

Canadian Blood Services' disposition reports suggested considerable variation in cryoprecipitate use and prompted this national audit.

STUDY DESIGN AND METHODS

Thirty-one institutions were invited to participate in a 2-month audit. Patient information and relevant laboratory and transfusion data were collected. Cryoprecipitate transfusions were categorized as appropriate if a fibrinogen level (taken 6 hr before/after transfusion) was not more than 1.0 g per L and inappropriate if the pretransfusion fibrinogen level was more than 1.0 g per L and posttransfusion fibrinogen level was more than 1.0 g per L or not performed. Appropriateness was categorized as undetermined if the pretransfusion fibrinogen level was not performed and the posttransfusion fibrinogen level was more than 1.0 g per L or not performed.

RESULTS

Overall, 25 of 31 invited hospitals agreed to participate. A total of 4370 units of cryoprecipitate were transfused in 603 events to 453 patients representing 62 percent of cryoprecipitate issued to hospitals during the time period. Comparison of the number of units of cryoprecipitate per 100 units of red blood cells (RBCs) transfused by each institution showed significant variation in practice (mean, 9 per 100 RBCs; range, 2 to 27 units). The single most common indication for cryoprecipitate was cardiac surgery (45.4% of events). Overall, 24 percent of cryoprecipitate transfusions were considered to be appropriate (pretransfusion fibrinogen level <or=1 g/L in 19% and posttransfusion fibrinogen level <or=1.0 g/L in another 5%), 34 percent were inappropriate, and in 42 percent appropriateness could not be determined.

CONCLUSION

A 2-month audit of cryoprecipitate use in Canada revealed that the majority of cryoprecipitate use in Canada is not in accordance with published guidelines.

Refractory headaches due to multilevel thoracic cerebrospinal fluid leaks

BACKGROUND

Spontaneous cerebrospinal fluid leak is a well-documented cause of postural headache. We report a medically refractory headache due to multilevel thoracic cerebrospinal fluid leaks.

CASE REPORT

A 44-year-old male with an acute onset of postural headache failed to respond to bed rest, hydration, and analgesics. Magnetic resonance imaging demonstrated a large cerebrospinal fluid leak centered at the right T4 and left T11 to 12 levels, with bony pathology evident at the lower thoracic level. Lumbar (L4 to 5) and computed tomography guided T4 to 5 level epidural blood patches provided minimal pain relief. Percutaneous epidural fibrin glue injection at T4 followed by a repeat computed tomography guided epidural blood patch led to significant but incomplete symptom relief. Subsequent imaging demonstrated persistent fluid at the T11 to 12 level. Fibrin glue and epidural blood patches at this level reduced but did not eliminate the leak and residual symptoms. Extensive corrective surgery was offered but declined by the patient.

CONCLUSION

Treatment of multifocal cerebrospinal fluid leaks can be challenging, particularly when at least part of the underlying etiology is fixed structural bony pathology.

Topical hemostatic agents: a review

Topical hemostatic agents play an important role in both common and specialized dermatologic procedures. These agents can be classified based on their mechanism of action and include physical or mechanical agents, caustic agents, biologic physical agents, and physiologic agents. Some agents induce protein coagulation and precipitation resulting in occlusion of small cutaneous vessels, while others take advantage of latter stages in the coagulation cascade, activating biologic responses to bleeding. Traditional and newer topical hemostatic agents are discussed in this review, and the benefits and costs of each agent will be provided.

Healing of full-thickness defects of the articular cartilage in rabbits using fibroblast growth factor-2 and a fibrin sealant

We have investigated in vitro the release kinetics and bioactivity of fibroblast growth factor-2 (FGF-2) released from a carrier of fibrin sealant. In order to evaluate the effects of the FGF-2 delivery mechanism on the repair of articular cartilage, full-thickness cylindrical defects, 5 mm in diameter and 4 mm in depth, which were too large to undergo spontaneous repair, were created in the femoral trochlea of rabbit knees. These defects were then filled with the sealant. Approximately 50% of the FGF-2 was released from the sealant within 24 hours while its original bioactivity was maintained. The implantation of the fibrin sealant incorporating FGF-2 successfully induced healing of the surface with hyaline cartilage and concomitant repair of the subchondral bone at eight weeks after the creation of the defect. Our findings suggest that this delivery method for FGF-2 may be useful for promoting regenerative repair of full-thickness defects of articular cartilage in humans.

Injectable Tissue-Engineered Cartilage Using a Fibrin Sealant

OBJECTIVE

To investigate a commercially available fibrin sealant as a vehicle for developing injectable tissue-engineered cartilage.

METHODS

Fibrin glue was mixed with autogenous chondrocytes from rabbits (n = 15). This isolate was injected along their nasal dorsa using 1 of 3 different fibrin glue concentrations. The samples were harvested at 8 weeks and compared with elastin and hyaline cartilage controls.

RESULTS

Neocartilage was created along a linear injection tract on the dorsa of the nasal bones in 5 of 15 rabbits. Higher thrombin concentrations proved to be directly correlated with successful creation of injectable cartilage. Histologically, the staining patterns of both hematoxylin-eosin and safranin O stains were identical to that of normal auricular control cartilage. The presence of elastin fibers was observed following Verhoeff staining. No foreign body reaction was observed from the host.

CONCLUSIONS

This study demonstrated a successful method for percutaneous injection of tissue-engineered cartilage as a mixture of chondrocytes suspended in fibrin glue. The thrombin concentration, along with the concentration of fibrinogen and chondrocytes, must be optimized to succeed consistently in cartilage growth.

New method to prepare autologous fibrin glue on demand

Fibrin-based sealants are commonly employed to arrest bleeding after surgery. Usually, fibrinogen obtained from pooled human plasma is used to prepare sealants, with attendant risk of blood-borne infections. Availability of autologous fibrinogen would eliminate this risk. To prepare autologous fibrin sealant, fibrinogen was precipitated from human plasma using protamine. Under optimal conditions (10-mg/mL protamine and 22 degrees C), 96 +/- 4% of clottable fibrinogen was recovered by a simple and inexpensive technique. Nearly 50% of the plasma factor XIII was also recovered with the fibrinogen. Using bovine thrombin, the fibrinogen was clotted (1) in a specially designed mold to measure tensile strength and (2) in a lap joint between 2 aortic vessel strips to measure adhesion strength. Tensile and adhesion strengths increased with increasing fibrinogen concentration, and they were increased by the addition of calcium chloride. The addition of aprotinin and -aminocaproic acid to the fibrinogen concentrate before clotting had no effect on the mechanical properties of the clots. After adding thrombin to sealant containing 15-mg/mL fibrinogen, maximum tensile strength was achieved in 1-5 min, and maximum adhesion strength was reached in 5-15 min. For the sealant with 30-60-mg/mL fibrinogen and added calcium, the tensile strength was equivalent to that of the commercial fibrin sealant Tisseel. The adhesion strength of sealant with 30-60-mg/mL fibrinogen exceeded the adhesive strength of Tisseel under identical conditions. Autologous fibrin sealant is an attractive alternative to commercial sealants. It can be readily prepared from 5-mL plasma or more and exhibits mechanical properties equivalent to those of the leading commercial sealant.

THERAPEUTIC ANGIOGENESIS BY INTRAMUSCULAR INJECTION OF FIBRIN PARTICLES INTO ISCHAEMIC HINDLIMBS

1. Fibrin gel has been used as a carrier of angiogenic molecules to promote neovascularization in animal models of limb ischaemia. However, little is known about the effects of fibrin itself under such pathological conditions. Accordingly, the present study tested the efficacy of fibrin in a rabbit model of acute hindlimb ischaemia. 2. Unilateral ischaemia was induced by resection of the left femoral artery. Seven days after surgery, fibrin particles (FP), which were free of fibrinogen, thrombin and vascular endothelial growth factor, were injected directly into the ischaemic thigh muscles. Twenty-four rabbits were divided into four groups, namely a control group receiving phosphate-buffered saline and three FP-treated groups receiving 5, 10 or 20 mg FP. 3. Collateral vessel development and limb perfusion were assessed by angiography, measuring the calf blood pressure ratio (BPR), thermographic scanning and the histological determination of capillary density. 4. At day 35 post-surgery, the treatment with 5 mg FP produced an augmentation of collateral vessel development (P < 0.01), increased numbers of capillaries (P < 0.05) and improved perfusion manifested by a higher blood flow (P < 0.01) and calf BPR (P < 0.05) compared with controls. Treatment with 10 and 20 mg FP had similar effects to those observed with 5 mg FP. 5. The present study reveals that FP promotes angiogenesis in a rabbit model of hindlimb ischaemia, thus providing a feasible approach to therapeutic angiogenesis in ischaemic diseases.

Management of isolated neck deformity

Rejuvenative surgery for isolated neck deformities can be fulfilling procedure for patients and surgeons. With precise understanding of the anatomy of the anterior neck, proper patient selection, and sound surgical execution, consistent and attractive postoperative outcomes can be expected in every case (Figs. 9, 10).