Abstract TP212: Robust Neuroprotection With PAF-R Antagonist Plus AT-NPD1 In Experimental Ischemic Stroke: Dose-response And Therapeutic Window

Abstract

Objective: We examined the neuroprotective efficacy, including dose-responses and therapeutic window of 1) LAU-0901, receptor antagonist of the bioactive phospholipid mediator platelet-activating factor (PAF-R) that downregulates pro-inflammatory signaling and has been shown efficacy in a stroke model and, 2) AT-NPD1 (Aspirin- triggered NPD1), its synthesis in the brain was discovered upon aspirin + DHA administration (Bazan et al. Exp Neurol., 2012) and induced cell-survival pathways, anti-inflammatory and neuroprotective activity in focal cerebral ischemia. Methods: Male SD rats underwent 2 hours of MCAo. Behavior testing (days 1-7) and ex vivo MRI on day 7 were conducted. In dose-response, rats were treated with LAU-0901 (45 and 60 mg/kg; IP), AT-NPD1 (111, 222, 333 μg/kg; IV), LAU-0901+AT-NPD1 (LAU-0901 at 3h and AT-NPD1 at 3.15h) or vehicle. In the therapeutic window, vehicle LAU-0901 (60 mg/kg), AT-NPD1 (222 μg/kg), and LAU-0901+AT-NPD1 were administered at 3, 4, 5, and 6h after onset of MCAo. Rats were perfused on day 7, and an ex vivo brain MRI was conducted using 11.7 T MRI. Hierarchal region splitting was used to distinguish the core from the penumbra. Results: LAU-0901 and AT-NPD1 treatments alone improved behavior by 40-42% and 20-30%, respectively, and LAU-0901+AT-NPD1 by 40% compared to the vehicle group. T2-weighted imaging (T2WI) volumes were reduced with all doses of LAU-0901 and AT-NPD1 by 73-90% and 67-83% and LAU-0901+AT-NPD1 by 94% compared to vehicle. In the therapeutic window, treatment with LAU-0901 and AT-NPD1 alone, when administered at 3h, improved behavior on day 7 by 35 and 28%. In contrast, LAU-0901+AT-NPD1, when administered at 3, 4, 5, and 6 hours, improved behavior by 50, 56, 33, and 26%. Ischemic core, penumbra, and total lesion volumes were dramatically reduced with LAU-0901+AT-NPD1 when administered at 3, 4, 5, and 6h by 93, 90, 82, and 84% compared to the vehicle. Conclusion: These data suggest that LAU-0901 and AT-NPD1 alone in low doses provide high-grade neuroprotection in the MCAo model. Combination therapy with LAU-0901 and AT-NPD1 is more effective than the single therapy, affording synergistic neuroprotection with improved neurological recovery when administered up to 6 h after focal cerebral ischemia in rats.