Quantification of galactosylsphingosine in the twitcher mouse using electrospray ionization-tandem mass spectrometry

Globoid cell leukodystrophy (Krabbe disease) is an autosomal recessive inherited neurodegenerative dis- order caused by the deficiency of the lysosomal enzyme � -galactosylceramidase. The pathogenesis of the disorder has been proposed to arise from the accumulation of the cy- totoxic metabolite galactosylsphingosine (psychosine). The twitcher mouse is a naturally occurring murine model of globoid cell leukodystrophy. We have developed a rapid, sensitive, and specific mass spectrometric method for deter- mining the galactosylsphingosine concentration in the tis- sues of twitcher mice. Galactosylsphingosine is extracted from the tissues in methanol, isolated using strong cation- exchange and C18 solid-phase extraction chromatography, and then directly analyzed using electrospray ionization- tandem mass spectrometry. A lactosylsphingosine internal standard has been employed for quantification. The assay demonstrated significant accumulation of galactosyl- sphingosine in the brain, spinal cord, and kidney of twitcher mice. It is anticipated that this method may be of use in the monitoring of experimental therapies for globoid cell leukodystrophy. —Whitfield, P. D., P. C. Sharp, R. Taylor, and P. Meikle. Quantification of galactosylsphingosine in the twitcher mouse using electrospray ionization-tandem mass spectrometry. J. Lipid Res. 2001. 42: 2092-2095.