Drug developers desperately need better tools in the laboratory to improve the 90% failure rate of drugs in clinical trials. Liver toxicity is still the leading cause of drug failure, despite extensive preclinical testing in surrogate animal species. HemoShear develops human surrogate technologies for target ID and validation and screening of compounds for safety and efficacy in the late discovery and early pre-clinical stages. HemoShear has developed a human vascular surrogate technology for identification and validation of novel targets and for screening and selection of optimal compounds for further development (US Patent 60/879,710 under review). Our human vascular surrogate device uniquely mimics the vascular anatomy (co- culture containing endothelial and smooth muscle cells, separated by a porous membrane) and hemodynamic environment during the early stages of atherosclerosis. The device enables investigation of the cellular and molecular mechanisms of human atherosclerosis and the identification of novel biomarkers and transcriptional pathways for development of improved drug therapies. Cell-based surrogate models are being used increasingly during drug development to provide more accurate predictions of human responses. This Phase I SBIR application proposes to develop a hemodynamic co-culture model of the liver using HemoShear's proprietary platform technology that will represent a far superior system with which to screen drug potential for hepatotoxicity, determine mechanisms of liver toxicity and identify novel targets for therapy. It is widely known that static, monoculture hepatocyte models utilized to study drug efficacy and toxicity are not predictive of the in vivo response, and represent ineffective models for target identification and validation in the drug development process because of the inherent loss of differentiated phenotype. Like the vasculature, recreating anatomical and physiological features important to normal liver function is necessary for an effective ex vivo model. For example, the biological response of the liver in vivo to both endogenous substrates as well as exogenous factors is dependent on the direct and indirect 'cross-talk'between the different cell types of the endothelium and epithelium. In addition, their survival and gene expression profiles are largely dependent on the local hemodynamics. Thus, the overall goal of this proposal is to develop a rat liver co-culture surrogate model that mimics in vivo physiology and hemodynamics. The model will consist of sinusoidal endothelial cells (SECs) and hepatocytes in co-culture where the SECs are exposed to sinusoid fluid hemodynamics, recreating in vivo cell phenotypes, ex vivo. If successful, this system will allow pharmaceutical companies to better understand the specific mechanism-of-action for drug efficacy and pre-clinical safety/toxicity compared to current monoculture, static systems. Additionally, success of this Phase I SBIR will lead to a Phase II application to develop a more advanced human model of hepatotoxicity and inflammatory disease, incorporating additional cell types, e.g. Kupffer and stellate cells. PUBLIC HEALTH RELEVANCE: Drug developers desperately need better tools in the laboratory to improve the 90% failure rate of drugs in clinical trials. Liver toxicity is still the leading cause of drug failure, despite extensive preclinical testing in surrogate animal species. HemoShear develops human surrogate technologies for target ID and validation and screening of compounds for safety and efficacy in the late discovery and early pre-clinical stages. This Phase I SBIR application proposes to develop a hemodynamic rat sinusoidal endothelial cell and hepatocyte co-culture model of the liver using HemoShear's proprietary platform technology;which will represent a far superior system to screen drug potential for hepatotoxicity, determine mechanisms of liver toxicity and identify novel targets for therapy. Success of this Phase I SBIR will lead to a Phase II application to develop a more advanced human model of hepatotoxicity and inflammatory disease, incorporating additional cell types, e.g. Kupffer and stellate cells.