SMPD1 and brain infarction: Based on the observation that Smpd1−/− mice exhibited exacerbated brain infarcts associated with increased brain leukocyte and polymorphonuclear neutrophil (PMN) infiltrates, whereas Smpd1+/− revealed reduced brain infarcts, we subsequently depleted PMNs in Smpd1+/+ and Smpd1−/− mice using anti-lymphocyte antigen-6 (locus G; Ly6G) antibody, evaluating the role of PMNs for I/R injury.