A novel vascular bioreactor for remodelling and testing mechanical properties of blood vessels

Vascular diseases are one the principal causes of death in industrial countries. Current therapies, based principally on the use of autologous grafts, result often limited by shortage of donor sites and by the not well-known mechanical and biochemical relationships between the principal components of vessel and the risk factors. For this reason we have designed and realised a bioreactor able to reproduce the physio-pathological situations of a vascular tract with an inner diameter inferior to 6 mm. The device has been before modelled with an analytical and finite element model to fix the principal features for its design such as topology, culture medium flow and transmural pressure, and to evaluate its correspondence with physio-pathological states. After this modelling phase the bioreactor has been realised in silicone by casting technique. In the system realised carotid arteries have been culture for 24 hours varying the transmural pressure applied. Vascular mechanical properties have been tested before and after the experiment in order to evaluate how this physical stimulus acts on them and in particular on the remodelling of extracellular matrix and orientation of collagen fibers. The results obtained have demonstrated that this device was able to reproduce different physiological and pathological situations.