Medizinische Universität Graz - Research portal
Selected Publication:
Wankhammer, K.
Zelluläre Besiedelung von Blutgefäßprothesen im Bioreaktorsystem.
[ Diplomarbeit/Master Thesis ] Karl-Franzens University Graz; 2012.
- Authors Med Uni Graz:
- Advisor:
- Lang-Olip Ingrid
- Altmetrics:
- Abstract:
- Abstract Due to the increasing number of cardiovascular diseases there is a high need of vascular grafts for blood vessel reconstruction. The limited availability of autologous vessels by reason of existing damages induces research on synthetic vascular grafts. In contrast to large calibre vascular grafts, prostheses with diameters smaller than 6 mm are highly susceptible to thrombosis. We aim to develop small calibre grafts close to in vivo blood vessels to reduce the problem of graft occlusion. Placental mesenchymal stromal cells (MSC) exert a survival enhancing and stabilizing effect on endothelial cells (EC). Therefore, a co-culture system of both cell types on ePTFE- prostheses should help to minimize the problem of graft occlusion. A main focus lies on the establishment of the ideal surface modification for ePTFE- prostheses to enable optimal cell attachment. Untreated or acid pre-treated small calibre ePFTE grafts were coated with gelatine (G), fibronectin (F) or fibrinogen- thrombin (FT) and seeded with human placental EC or MSC. Cell attachment was determined after 50 min - 3 h. Additionally, attached cells were exposed to a pulsatile flow in a bioreactor for 24 hours or 1 week. The morphology and efficiency of cell adherence was analysed after HE staining and by scanning electron microscopy. Cell identity was evaluated by immunohistochemistry. Ultrastructural analyses showed pores on the ePTFE surface which are filled with small overlapping fibres connected to dense material. The gaps between the fibres show a length of 10 - 18 p.m and a width 1 - 3 p.m. MSC and EC preferred attachment on the compact dense areas of ePTFE. They attached well on the FT coating, but FT showed an irregular layer and delaminations. Only a few cells attached on G. F was the most suitable coating material. Adherence of MSC and EC on fibronectin coated grafts could be determined already after 50 min. The cell attachment sustained under physiological flow conditions (24 h and 1 week). Both cell types showed typical antigen expression. ePTFE- grafts were successfully seeded with EC and MSC. The porous structure of ePTFE enables a physiological permeability which allows the interaction of EC and MSC via paracrine factors. Thus, MSC could maintain their surviving enhancing effects also on ePTFE-grafts.