Differential Lipid Signatures of Lumbar and Cisternal Cerebrospinal Fluid.

backgroundThe molecular composition of cerebrospinal fluid (CSF) is often used as a key indicator of biochemical alterations within distinct brain and spinal cord fluid compartments. The CSF protein content in lumbar CSF samples is widely employed as a biomarker matrix for diagnosing brain-related pathological conditions. CSF lipid profiles may serve as promising complementary diagnostics, but it remains unresolved if the lipid distribution is consistent along the neuroaxis.

methodsThe lipid composition was determined with liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) in cisternal CSF obtained from healthy subjects undergoing preventive surgery of an unruptured aneurism (

resultsWe reveal discernible variations in lipid composition along the neuroaxis, with a higher overall lipid concentration in cisternal CSF, although with different relative distributions of the various lipid classes in the two compartments. The cisternal CSF contained elevated levels of most lipid classes, e.g., sphingomyelins, lysophosphatidylcholines, plasmenylphosphatidylcholines, phosphatidic acids, and triacylglycerols, whereas a few select lipids from the classes of fatty acids, phosphatidylcholines, amides and plasmenylphosphatidylethanolamines were, oppositely, elevated in the lumbar CSF pool.

conclusionsThe distinct lipid distribution along the neuroaxis illustrates that the molecular constituents in these two CSF compartments are not uniform. These findings emphasize the necessity of establishing a lumbar lipid index for the accurate interpretation of the cranial CSF lipid profile.