Abstract WMP9: Pharmacological Characterization Of The Water Soluble Neurosteroid NTS-104 In The Rat Embolic Stroke Model

Background: Our objective was to characterize the pharmacodynamic changes induced by NTS-104/105 within the brain and plasma in rats following embolic middle cerebral artery occlusion (eMCAO). Previous pharmacokinetic analysis indicated that NTS-104 is rapidly metabolized in the blood to form the active compound NTS-105, which is readily detected in the brain. In contrast, NTS-104 does not cross the blood-brain barrier. Methods: Adult, male Wistar rats were subjected to eMCAO. Stroke severity was defined by Neurological Severity Score (NSS) assessment. Only rats that scored >8 on a 13-point scale were included. Rats were dosed IM with vehicle, or NTS-104 (5mg/kg or 20mg/kg) at 6 hours after stroke. Brain and plasma samples rats were collected at 6, 12, or 24hrs after injection. Samples were screened for expression of AKT, pAKT and against a panel of 67 cytokines by quantitative ELISA. Results: We found that NTS-104 treatment induced a significant reduction in IL-6, GM-CSF, MCP-1, IL-1α, RAGE, VEGF, and ICAM-1 levels within the brains of rats following intramuscular injection of 20 mg/kg NTS-104 at 6-hours after eMCAO compared to vehicle treated control rats. In contrast, treatment with 5mg/kg NTS-104 did not induce similar time and dose dependent changes in these specific cytokines relative to vehicle treated controls. NTS-104 treatment also significantly reduced IL-6 and GM-CSF levels, while increasing galectin-1 levels, within the plasma of these same rats in a time and dose dependent manner similar to what was observed within the brain. We further detected a significant increase in the levels of phosphorylated AKT (pAKT) within the brains of stroked rats treated with 20 mg/kg NTS-104 but not with 5 mg/kg. Conclusion: These data demonstrate that treatment with NTS-104 results in the significant activation of the AKT cell survival signaling pathway and significantly reduces critical neuroinflammatory signaling after stroke in a time and dose dependent manner.