Direct profiling of phospholipids and lysophospholipids in rat brain sections after ischemic stroke

Abstract

Stroke, a deleterious cerebrovascular event, is caused by a critical reduction in the blood flow to the brain parenchyma that leads to brain injury and loss of brain functions. The inflammatory responses following ischemia often aggravate the neurological damage. Several pro-inflammatory mediators released after stroke are closely related to the metabolism of phospholipids. In this study we directly profiled the changes in phospholipids in the infarcted rat cerebral cortex 24 hours after middle cerebral artery occlusion (MCAO) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Several phosphatidylcholine (PC) species and sphingomyelin (SM) were significantly decreased after infarction. The cationization pattern of the remaining PCs showed a prominent shift from a mostly potassiated or protonated form to a predominantly sodiated pattern. Stroke also elevated the lysophosphatidylcholines (LPCs) and heme in tissue. The isobaric pairs in PC and LPC classes were resolved by masses through their respective alkali metal adducts in the presence of CsCl. The major fatty acyl LPC species were also structurally confirmed by MALDI-MS/MS. Overall, the results described the changes in PC and LPC species in the infarcted rat cortex. The elevated tissue levels of LPCs and heme signify the ongoing pathological lipid breakdown and the state of parenchymal inflammation. The elevated LPC level in tissue suggests a means of intervention through lysophospholipid metabolism that could potentially benefit the management of stroke and other acute neurological injuries.

Mass spectrometry images acylcarnitines, phosphatidylcholines, and sphingomyelin in MDA-MB-231 breast tumor models

“…The identifi cation of all lipid species involved collisional activation (see Fig. 5 ( 56 ), and following heart ( 16 ) and brain ( 19,57 ) injury. Multiple different bioactive lysophospholipids exhibit pleomorphic effects on multiple cell lineages, including breast and ovarian cancer cells ( 58,59 ).…”

Global changes in phospholipids identified by MALDI MS in rats with focal cerebral ischemia

“…Changes in smaller mass lipid species in the infarcted region Koizumi et al ( 24) and Wang et al ( 25 ) showed that one specifi c LPC (16:0) at m/z 496.3 is induced after brain ischemic injury. Our present data showed several other apoptosis.…”

A simple desalting method for direct MALDI mass spectrometry profiling of tissue lipids

“…Surgical induction of ischemic stroke in rats, the neurological evaluation of the animals, and histological verifi cation have been described previously ( 7 ). Rat brains were collected 24 h after stroke induction.…”

“…Therefore, the highly abundant endogenous potassium and sodium ions might have conceivably biased the mass spectrometry presentations of tissue PCs ( 3 ). Changes in tissue cations due to the pathological effects such as edema ( 5,6 ) further enhanced the ionization of alkalinated PCs and SMs in the direct MALDI profi ling ( 7 ). Adding lithium ( 1 ), potassium ( 3 ), or cesium ( 7,8 ) in the MALDI matrix solution was attempted to circumvent this obstacle.…”

“…Changes in tissue cations due to the pathological effects such as edema ( 5,6 ) further enhanced the ionization of alkalinated PCs and SMs in the direct MALDI profi ling ( 7 ). Adding lithium ( 1 ), potassium ( 3 ), or cesium ( 7,8 ) in the MALDI matrix solution was attempted to circumvent this obstacle. However, protonated PCs and SMs were still easily detected with their alkalinated counterparts in most of the MALDI spectra acquired by this approach.…”