VascuTrap

The VascuTrap project aims to develop bioactive vascular implants. The luminal surface of synthetic vessels is to be coated with a highly specific capture protein that binds stem cells circulating from the blood stream, more precisely vascular precursor cells (EPC), so that very rapid natural and thus antithrombogenic cell colonisation is achieved for better tolerance of the synthetic vessel. The capture protein is bound to a specially reactive, biomaterial-based thin layer on the vessel material. The capture protein is directed against an EPC-specific protein so that only endothelial precursor cells are selectively recruited from the large number of blood cells.
To achieve this goal, three components (synthetic vessels, a reactive thin film and a highly specific capture protein) are to be combined in an interdisciplinary approach to form a novel implant type.
As synthetic blood vessels, approved standard implants of different diameters made of non-absorbable polymers/block copolymers are used. The polymers are biocompatible and are produced either from uniform membranes or from interwoven polymer threads. Subsequent process steps are used to test surface modifications that enable the binding of the capture protein.
The highly specific capture protein is an antibody against cell surface protein. This protein is only expressed on endothelial progenitor cells (EPC) of the blood, but not on other blood cells. Accordingly, EPCs can be enriched very selectively and efficiently by means of a highly affine monoclonal antibody from the multitude of blood cells, whereupon the precursor cells differentiate into endothelial cells. The antibody is generated by a patented process in which vectors containing the gene for the target protein are applied intracutaneously in rats.
The biological efficacy of the individual components and, in particular, their combination into a bioactive implant are investigated on two levels, both cell-biologically in vitro (NMI) and preclinically in animal experiments (University Hospital Tübingen).
The cell biological in vitro profiling of the modified vessels and their individual components is quantitatively and qualitatively tested using a large number of cell culture methods. Measurement parameters are biocompatibility, specific versus non-specific cell adherence, proliferation, migration and differentiation.