Poster Session 1 - C10
1,2,3,4Anju M Philip, 2,3Patricia Gali, 2,3Yuexin Shan, 2,3Claudia dosSantos, 1,2,3,4Xiao-Yan Wen
1. Dept. of Physiology, University of Toronto; 2. Keenan Research Centre for Biomedical Science and Li Ka Shing Knowledge Institute of St. Michael’s Hospital, Toronto; 3. Institute of Medical Sciences, University of Toronto; 4. Zebrafish Centre for Advanced Drug Discovery, St. Michael’s Hospital, Toronto
Loss of endothelial barrier function leading to the leakage of plasma-borne proteins, tissue edema, and tissue/organ damage is a major pathological feature of multiple disease states including sepsis. Severe sepsis remains one of the leading causes of hospital deaths (50-80%) worldwide and the economic burden for sepsis has been estimated at $16 billion per year in North America, more than the cost for any single cancer. Despite intense research into the pathogenesis of sepsis, over 100 clinical trials of anti-sepsis therapeutics failed and the current therapy for this devastating syndrome is primarily supportive. Currently there is no therapy to effectively limit or/and reverse the loss of capillary membrane permeability. Part of the difficulty in identifying novel therapies is the inability to replicate the complexities of human diffuse microvascular leakage and sepsis in fast, easy to use, cheap and informative animal models to fast track drug candidates to preclinical models. Hypothesis: Developing a zebrafish model for sepsis will allow high throughput screening of thousands of small molecules in vivo, helping to fast track drug candidates to preclinical models. Methodology: Three day old zebrafish larvae treated with lipopolysaccharide (LPS) develop critical features of sepsis including vascular leakage, reactive oxygen species (ROS) production, inflammatory cell infiltration and mortality. Using a robotic system, hundreds of “septic” fish in microplates can be treated with drug compounds that are tested for their ability to limit and/or reverse 3 primary features of the disease: mortality, vascular leak and ROS production. Top leads identified are fast-tracked for further studies in human pulmonary microvascular endothelial cell (HPMEC) models of vascular leakage using FITC dextran assays and TEER measurements as well as mice Caecum Ligation and Puncture (CLP -a clinically relevant model of sepsis) models. Results and Conclusion: Drug U, a lead compound identified through this approach rescued mortality, LPS induced leakage of microinjected quantum dots and increased ROS production in the zebrafish. Drug U also protected HPMECs from LPS induced FITC dextran leakage, and further protected mice from CLP induced mortality and mitigated Evan’s Blue Dye leakage in different organs compared to mice treated with placebo. In conclusion, using a fast, cheap and efficient drug screening approach, we have identified a potential novel therapeutic for vascular leakage and sepsis.