ABSTRACT
We describe herein that a pyrazine derivative, T-705 (6-fluoro-3-hydroxy-2-pyrazinecarboxamide), is protective for a lethal West Nile virus infection in rodents. Oral T-705 at 200 mg/kg administered twice daily beginning 4h after subcutaneous (s.c.) viral challenge protected mice and hamsters against WNV-induced mortality, and reduced viral protein expression and viral RNA in brains. The minimal effective oral dose was between 20 and 65 mg/kg when administered twice a day beginning 1 day after viral s.c. challenge of mice. Treatment could be delayed out to 2 days after viral challenge to still achieve efficacy in mice. Further development of this compound should be considered for treatment of WNV.
Subject(s)
Amides/administration & dosage , Pyrazines/administration & dosage , West Nile Fever/drug therapy , West Nile virus/drug effects , Administration, Oral , Animals , Brain/metabolism , Brain/virology , Cricetinae , Disease Models, Animal , Drug Administration Schedule , Female , Humans , Mesocricetus , Mice , Mice, Inbred C57BL , West Nile Fever/metabolism , West Nile Fever/virologyABSTRACT
Blood-brain barrier (BBB) permeability was evaluated in mice and hamsters infected with West Nile virus (WNV, flavivirus) as compared to those infected with Semliki Forest (alphavirus) and Banzi (flavivirus) viruses. BBB permeability was determined by measurement of fluorescence in brain homogenates or cerebrospinal fluid (CSF) after intraperitoneal (i.p.) injection of sodium fluorescein, by macroscopic examination of brains after i.p. injection of Evans blue, or by measurement of total protein in CSF compared to serum. Lethal infection of BALB/c mice with Semliki Forest virus and Banzi virus caused the brain : serum fluorescence ratios to increase from a baseline of 2-4% to as high as 11 and 15%, respectively. Lethal infection of BALB/c mice with WNV did not increase BBB permeability. When C57BL/6 mice were used, BBB permeability was increased in some, but not all, of the WNV-infected animals. A procedure was developed to measure BBB permeability in live WNV-infected hamsters by comparing the fluorescence in the CSF, aspirated from the cisterna magnum, with the fluorescence in the serum. Despite a time-dependent tendency towards increased BBB permeability in some WNV-infected hamsters, the highest BBB permeability values did not correlate with mortality. These data indicated that a measurable increase in BBB permeability was not a primary determinant for lethality of WNV infection in rodents. The lack of a consistent increase in BBB permeability in WNV-infected rodents has implications for the understanding of viral entry, viral pathogenesis and accessibility of the CNS of rodents to drugs or effector molecules.
