Sphingolipidomics Investigation of the Temporal Dynamics after Ischemic Brain Injury

Sphingolipids (SPLs) have been proposed as potential therapeutic targets for strokes, but no reports have ever profiled the changes of the entire range of SPLs after a stroke. This study applied sphingolipidomic methods to investigate the temporal and individual changes in the sphingolipidome including the effect of atorvastatin after ischemic brain injury. We conducted sphingolipidomic profiling of mouse brain tissue by liquid chromatography-electrospray ionization tandem mass spectrometry at 3 h and 24 h after 1 h of middle cerebral artery occlusion (MCAO), and SPL levels were compared with those of the control group. At 3 h post-MCAO, ceramides (Cers) exhibited an increase in levels of long-chain Cers but a decrease in very-long-chain Cers. Moreover, sphingosine, the precursor of sphingosine-1-phosphate (S1P), decreased and S1P increased at 3 h after MCAO. In contrast to 3 h, both long-chain and very-long-chain Cers showed an increased trend at 24 h post-MCAO. Most important, the administration of atorvastatin improved the neurological function of the mice and significantly reversed the SPL changes resulting from the ischemic injury. Furthermore, we used plasma samples from nonstroke control and stroke patients at time points of 72 h after a stroke, and found a similar trend of Cers as in the MCAO model. This study successfully elucidated the overall effect of ischemic injury on SPL metabolism with and without atorvastatin treatment. The network of SPL components that change upon ischemic damage may provide novel therapeutic targets for ischemic stroke.