Doctor of Philosophy, Case Western Reserve University, 2013, Biomedical Engineering

Uncontrolled hemorrhage comprises 60-70% of trauma-associated mortality in the absence of other lethal conditions (e.g. damage to central nervous or cardiac system). Immediate intervention is critical to improving chances of survival. While there are several products to control bleeding for external wounds including pressure dressings, tourniquets or topical hemostatic agents there are few, if any, effective treatments that can be administered in the field to help staunch internal bleeding. Intravenous hemostatic nanoparticles that augment blood clotting when administered after trauma have been previously shown to half bleeding times in a femoral artery injury model in rats. The aims of the present study were to: 1) Determine their efficacy in a lethal hemorrhagic liver injury model, 2) determine the impact of targeting ligand concentration on hemostasis, and 3) test them in a clinically relevant porcine model of hemorrhage. Nanoparticle administration (GRGDS-NP1, 40 mg/kg) after lethal liver resection in the rat increased 1-hour survival to 80% compared to 40-47% in controls. Targeting ligand conjugation was then increased 100-fold (GRGDS-NP100), and a dosing study performed. GRGDS-NP100 hemostatic nanoparticles (2.5 mg/kg) were efficacious at doses 8-fold lower than GRGDS-NP1, and increased 1-hour survival to 92%. In vitro analysis using rotational thromboelastometry (ROTEM) confirmed the increased dose-sensitivity of GRGDS-NP100 and laid the foundation for methods to determine optimal ligand concentration parameters. Hemostatic nanoparticles were then tested in a clinically relevant porcine liver injury model, which elucidated an unexpected adverse reaction, comprised of a massive hemorrhagic response. A naive (uninjured) porcine model was then employed. These experiments revealed an adverse reaction consistent with complement activation related pseudoallergy (CARPA), which could be mediated by tuning nanoparticles' zeta potential. Neutralizing the nanopa (open full item for complete abstract)

Committee: Erin Lavik Sc.D. (Committee Chair); Jeffrey Ustin M.D. (Committee Member); Horst von Recum Ph.D. (Committee Member); Robert Miller Ph.D. (Committee Member) Subjects: Biomedical Engineering; Biomedical Research; Medicine