Characterization of the Sphingolipidome of the Peri-Infarct Tissue during Hemorrhagic Transformation in a Mouse Model of Cerebral Ischemia.

Background: Cardiovascular diseases like stroke cause changes to sphingolipid mediators like sphingosine 1-phosphate (S1P) or its ceramide analogs, which bear the potential to either alleviate or exacerbate the neurological damage. Therefore, the precise identification of alterations within the sphingolipidome during ischemic stroke (IS) and hemorrhagic transformation (HT) harbors a putative therapeutic potential to orchestrate local and systemic immunomodulatory processes. Due to the scarcity of research in this field, we aimed to characterize the sphingolipidome in IS and HT.

Methods: C57BL/6 mice underwent middle cerebral artery occlusion (MCAO) and specimens of the peri-infarct tissue were taken for sphingolipid profiling.

Results: Ischemic stroke resulted in reduced S1P whilst ceramides were elevated six hours post ischemia onset. However, these differences were nearly revoked at 24 hours post ischemia onset. Moreover, the topmost S1P and ceramide levels were linked to the presence of HT after MCAO. In this study we show the characterization of the sphingolipidomic landscape of the peri-infarct tissue after ischemic stroke and HT. Especially, highest values of S1P, C 18 lactosylceramide, C 18 glucosylceramide, and C 24:1 ceramide were nearly entirely expressed by mice with HT.

Conclusions: Our results warrant further investigations into the immunomodulatory consequences of altered sphingolipid species for the development of HT after IS.