Target Identification: Model for Gram- negative Sepsis

The project “Target Identification” aims to investigate as yet unknown factors activated in the course of sepsis. Sepsis is defined as a spectrum of clinical conditions caused by an intense systemic immune response of the body to an infection and is characterised by systemic inflammation, including activation of the complement and coagulation systems. Extracorporeal adsorptive therapy makes it possible to interfere with the main targets in sepsis. Therefore, specific factors could be removed from patients’ blood to stop the course of sepsis and to stabilise their immune systems. Sepsis is a complex disease with many unknown and thus unidentified factors. This project should help to discover and identify such unknown factors and investigate the possible benefits of adsorption for patients. Another focus of this project is the establishment of an artificial blood vessel. Investigations of endothelial cell (EC) behaviour and EC interactions with different types of blood cells pose a challenge with respect to experimental design in cell culture models. Optimised growth conditions of cells and well-defined shear stress are critical in an in vitro system. Omitting these factors produces cell types that are not physiological, which leads to biased results and false interpretations. Therefore, a specially designed EC bioreactor that simulates natural human blood vascular conditions, particularly in terms of morphology, the growth pattern of ECs, and flow conditions, is necessary for the reconstitution and simulation of the natural blood vessels in vivo. The main objective of this project is to design and develop an EC culture model that could simulate blood vessel physiology. In this model, isolated human umbilical vein endothelial cells (HUVECs) line the inside surface of polysulfone (PS) tubing under a pulsatile flow in a bioreactor set-up that has separate “intra-vascular” and “extra-vascular” perfusion reservoirs. Additionally, smooth muscle cells (SMCs) form a confluent layer of cells on the outer capillary surface, while THP-1 monocytes are circulated through the system to mimic human blood flow.