Mechanisms of fibrinolysis in human mesenchymal stem cells (MSC) were investigated. It was found that human mesenchymal stem cells show fibrinolytic activity in vitro. It was also found that components of the fibrinolytic system like plasminogen-activators uPA and tPA, the uPA-receptor and the inhibitor PAI-1 are expressed constitutively and their expression is regulated by cytokines. Results show that real-time PCR shows a marked increase of uPA expression after stimulation with TGF-β, while uPAR and tPA expression are enhanced by bFGF.