Abstract 3494: LOXblock-1 Provides Efficient, Specific, And Long-lasting Neuroprotection Against Transient Focal Ischemia In Mice By Inhibiting 12/15-Lipoxygenase

• Published in: Stroke (1970) Vol. 43; no. suppl_1
• Main Authors: Yigitkanli, Kazim, Pekcec, Anton, Pallast, Stefanie, Mandeville, Emiri, Joshi, Netra, Smirnova, Natalya, Gazaryan, Irina G, Ratan, Rajiv R, Witztum, Joseph L, Holman, Theodore R, Lo, Eng H, Van Leyen, Klaus
• Format: Journal Article
• Language: English
• Published: 01-02-2012
• ISSN: 0039-2499; 1524-4628
• DOI: 10.1161/str.43.suppl_1.A3494

Abstract only
Background and Purpose -
Acute phase stroke treatment options are currently very limited. We have previously demonstrated 12/15-lipoxygenase (12/15-LOX) to initiate an apoptotic cell death cascade, contributing to neuronal cell death, but also vascular leakage and edema formation in the ischemic brain. The current study was designed to test if a novel inhibitor LOXBlock-1, can specifically reduce 12/15-LOX activity in vivo, and provide efficient and long-lasting protection against stroke-induced injury.
Methods -
In vitro protection by LOXBlock-1 was tested in HT22 cells. A cell-based reporter assay determined activation of HIF1a and NRF2. The lipoxygenase metabolite 12-HETE was measured using a commercial EIA kit, and confirmed by HPLC/mass spectrometry. We injected LOXBlock-1 intraperitoneally in mice subjected to middle cerebral artery occlusion (MCAO). Immunohistochemistry was used to detect MDA-modified lysine in the ischemic brain, TTC and H&E stains were used to determine infarct size. Neurological severity score and corner test were used to evaluate behavioral outcome. Intracerebral hemorrhage was induced by collagenase injection.
Results -
Nanomolar LOXBlock-1 protected HT22 cells against oxidative glutamate toxicity. LOXBlock-1 reduced 12-HETE levels, without activating HIF1a- and NRF2-dependent pathways. One day after MCAO, MDA-modified lysine co-localized with 12/15-LOX in the peri-infarct cortex, and LOXBlock-1 reduced hemispheric swelling, levels of 12-HETE, and infarct size. After 14 days, infarct size remained reduced, and behavioral outcome was improved. LOXBlock-1 did not increase collagenase-induced hemorrhage.
Conclusion -
12/15-LOX inhibition by LOXBlock-1 provides effective and long-lasting protection against transient focal ischemia in mice, without worsening hemorrhage. LOXBlock-1 may be a suitable acute phase stroke treatment.