INTRODUCTION:Progression of acute liver injury continues long after most of the toxicant has been eliminated from the body. sPLA2 has been previously shown to mediate this progressive phase of injury.
OBJECTIVES:To evaluate the role of sPLA2 inhibitor Varespladib in mitigating progression of injury. We hypothesize that Varespladib confers protection against APAP-induced acute liver failure.
METHODS:A pilot study suggested 420 mg/kg APAP(LD 80) to be appropriate for testing the hypothesis in C57/BL6J mice. We then went on to test our treatment with Varespladib, which required DMSO as its vehicle. However, inclusion of DMSO in our experiments conferred protection against liver injury. To overcome this hurdle, we carried out more studies to 1) determine a dose of APAP that would exhibit acute liver failure in the presence of DMSO, and 2) determine a suitable solvent cocktail for Varespladib using minimum DMSO and achieve a decent volume for ip injections. After a series of solubility and titration experiments, a dose of 60 uL/kg of DMSO+550 mg/kg APAP was finalized. Mice either received APAP+DMSO (Control) or APAP+Varespladib (treatment). A time course study will be done to collect serum and liver tissue at 0,3,6,12,24,36,48,72 and 96 hrs. Samples will be further analyzed for bioactivation of APAP (CYP2E1/CYP3A4, GSH, APAP-liver protein adducts). Liver injury will be assessed by ALT, AST, and histopathology. sPLA2 activity will be assessed for effective inhibition. Liver regeneration will be assessed by PCNA staining. Prostaglandins will be measured to investigate their role in mediating progression/regression downstream of sPLA2.
RESULTS:Our data thus far demonstrate that sPLA2 inhibition via Varespladib confers protection against APAP-induced acute liver failure as evident by LD40 in control group and LD20 in the Varespladib-treated group.
CONCLUSION:Varespladib seems to be conferring protection against progression of acute liver injury.
Available at: http://works.bepress.com/vishakha_bhave/18/