Optimized thrombin dilution protocol for a slowly setting fibrin sealant in surgery

Abstract

Zusammenfassung. Grundlagen: Bei vielen chirurgischen Anwendungen (z. B. plastische und rekonstruktive Chirurgie) von Fibrinkleber ist eine längere Verarbeitungszeit von etwa 30-60 s vorteilhaft. Das kann durch eine Verdünnung der Thrombin-Komponente auf etwa 5 IU/ml erreicht werden. Ziel dieser Studie war es, ein optimales Verdünnungsmedium für die Thrombin-Komponente zu definieren, welches einerseits keine Veränderungen in den funktionellen Parametern des Fibrinklebers mit sich bringt und andererseits einfach und mit im OP vorhandenen Bestandteilen hergestellt werden kann.Methodik: Folgende Methoden kamen zur In-vitro-Beurteilung der Verdünnungsmedien zum Einsatz: Klebefestigkeit im Rattenhaut-Modell, Turbidimetrie und Rasterelektronenmikroskopie zur Bestimmung der Clot-Struktur, Reißfestigkeit der Fibrinclots durch Messen der zum Reißen nötigen Kraft. Die Fibrin-Quervernetzung in Abhängig-keit der Ca 2+ -Konzentration wurde durch quantitative Elektrophorese bestimmt.Ergebnisse: Das Verdünnungsmedium, das in vielen Kriterien die besten Ergebnisse gezeigt hat, enthält nur Kalziumchlorid in einer Konzentration von etwa 20 mM. Verdünnungsmedien mit einer zu hohen Ionenstärke ergaben Clots, die durch schlechte Reiß-und Klebefestigkeit, dünne Fibrinfasern und geringe Clot-Elastizität gekennzeichnet waren. In Abwesenheit von Kalzium kam es zu schlechter Fibrinquervernetzung und daraus resultierend zu schwachen und schlecht adherierenden Fibrinclots.Schlussfolgerungen: Das optimale Verdünnungsme-dium für die Verdünnung von Thrombin für einen langsamer bindenden Fibrinkleber wird angegeben.Schlüsselwörter: Fibrinkleber, Thrombin, Reißfestig-keit, Klebefestigkeit, Fibrinclot-Mikrostruktur.Summary. Background: Fibrin sealants find applications in many surgical fields (e.g., plastic and reconstructive surgery) where a slower setting time of about 30 to 60 s is beneficial. This can be achieved by diluting the thrombin component of the fibrin sealant to a concentration of about 5 IU/ml. This work was carried out to define an optimal dilution medium for thrombin which maintains all relevant functional parameters of the fibrin sealant and which is easy to prepare with components available in most operating theaters.Methods: Different performance criteria of a fibrin sealant were tested in vitro by the following methods: adhesive strength in a rat skin adhesion model, turbidimetry and scanning electron microscopy to determine the fibrin clots structure, tensile strength of the fibrin clots by measuring the force at break. The cross-linking of the fibrin sealant by factor XIII (FXIII) as a function of the calcium concentration was assessed by quantitative electrophoresis.Results: A dilution medium containing only calcium chloride in a concentration of about 20 mM performed best in most of the applied test systems. Dilution media with high ionic strength resulted in clots with low adhesive and tensile strength, thin fibrin fibers, and low clot elasticity. Dilution media without calcium prevented proper crosslinking of the result...

Human mesenchymal stem cells: Influence of oxygen pressure on proliferation and chondrogenic differentiation in fibrin glue in vitro

“…To achieve a highly porous matrix the fibrin sealant has to be diluted. Dilution media with high ionic strength results in clots with low adhesive and tensile strength, thin fibrin fibers, and low clot elasticity 36. It is known that the ionic strength has a significant influence on the fibrin micro architecture 37.…”

“…Dilution media with high ionic strength results in clots with low adhesive and tensile strength, thin fibrin fibers, and low clot elasticity. 36 It is known that the ionic strength has a significant influence on the fibrin micro architecture. 37 In our approach, in order to achieve a large-pored network with the slow-setting fibrin sealant, we chose sodium chloride (NaCl) for the dilution of the thrombin component.…”

Tissue adhesives in ocular surgery

“…When injected, the two components are mixed in equal volumes at the point of delivery. The setting time is dependent on the concentration of the thrombin component [135]. The thrombin converts the fibrinogen to fibrin by enzymatic action at a rate determined by the concentration of thrombin.…”

Sustained (rh)VEGF165 release from a sprayed fibrin biomatrix induces angiogenesis, up‐regulation of endogenous VEGF‐R2, and reduces ischemic flap necrosis

“…The sealer protein component (Fibrinogen 75–115 mg/mL) was reconstituted with a fibrinolysis inhibitor solution (Aprotinin 3,000 KIU/mL) and spiked with (rh)VEGF 165 (200 ng/mL). The thrombin component (500 IU/mL) was reconstituted with CaCl 2 (40‐μmol/mL) and diluted to 4 IU/mL 18 . Five fibrin matrices were made by mixing 75 μL of the sealer protein and (rh)VEGF 165 solution with 75 μL of the thrombin component at 37 °C.…”

“…The thrombin component (500 IU/mL) was reconstituted with CaCl 2 (40-mmol/mL) and diluted to 4 IU/mL. 18 Five fibrin matrices were made by mixing 75 mL of the sealer protein and (rh)VEGF 165 solution with 75 mL of the thrombin component at 37 1C. The resulting 150 mL fibrin matrix contained 200 ng/mL of (rh)VEGF 165 .…”