Experimental evaluation of microplasmin - an alternative to vital dyes

Complete separation of the vitreous from the retina is a major goal of vitrectomy. Mechanical vitrectomy, however, is not able to meet this need because remnants of the vitreous cortex are left behind at the retinal surface, resulting in incomplete posterior vitreous detachment (PVD). As incomplete PVD and an attached vitreous cortex are associated with the progression of common retinal diseases including diabetic retinopathy and maculopathy, central retinal vein occlusion, and proliferative vitreoretinopathy, induction of complete PVD is a major issue both in vitreoretinal surgery and in medical retina. This chapter focuses on one of the most promising current concepts of pharmacologic vitreolysis, i.e. microplasmin-assisted vitrectomy. Microplasmin (Thrombogenics Ltd., Dublin, Ireland) is a recombinant molecule consisting of the catalytic domain of human plasmin. It shares the same catalytic properties like human plasmin, but it is much more stable compared to plasmin. It has been shown previously that both plasmin and microplasmin are capable of inducing PVD. Herein, we report on the preclinical work regarding plasmin and microplasmin which led to the clinical investigation of microplasmin.