Stabilization of fibrin-chondrocyte constructs for cartilage reconstruction

Cartilage replacement is a challenging issue in reconstructive surgery. In the past few years, tissue engineering has been tested as a means of cartilage reconstruction. Tissue engineering of cartilage depends on the use of adequate polymers. In addition to several natural and synthetic polymers, fibrin gel has been tested for cartilage reconstruction. However, fibrin is intrinsically unstable. The purpose of this study was to stabilize fibrin by increased fibrinolytic inhibition and to test these preparations for cartilage reconstruction with human nasal septum chondrocytes. Increased fibrinolytic inhibition was achieved with aprotinin and tranexamic acid. Stabilized fibrin-chondrocyte constructs were cultivated for 4 weeks in vitro and compared with constructs made of standard, commercially available fibrin gel. The effect of several cell densities on stability, and the production of extracellular matrix components, were assessed on the basis of histology and immunohistochemistry. In contrast to constructs made of standard fibrin gel, stabilized constructs were stable for the entire observation period and demonstrated no or only minor shrinkage. Cells in these constructs appeared to be viable, and an extracellular matrix could be demonstrated in all constructs. The authors conclude that fibrin-chondrocyte constructs stabilized by increased fibrinolytic inhibition could be an adequate tool for cartilage reconstruction.