Relative distribution of Gb3 isoforms/analogs in NOD/SCID/Fabry mice tissues determined by tandem mass spectrometry.

AIM: Fabry disease is a lysosomal storage disorder leading to glycosphingolipid accumulation in different organs, tissues and biological fluids. The development of a Fabry disease gene therapy trial is underway in Canada. A tool to determine the distribution of Gb3 biomarkers in tissues of Fabry mice might be applicable to monitor the effect of gene therapy. Results & methodology: An ultra-performance LC-MS/MS (UPLC-MS/MS) method for the analysis of 22 Gb3 isoform/analogs in various Fabry mice tissues was developed and validated. Marked variation in biomarker organ distribution was found with higher levels in the spleen, followed by the small intestine, kidneys, lungs, heart, liver and brain. CONCLUSION: The devised method is sensitive and useful for the evaluation of biomarker profiles in Fabry mice.

Glycosphingolipid storage in Fabry mice extends beyond globotriaosylceramide and is affected by ABCB1 depletion.

AIM: Fabry disease is caused by α-galactosidase A deficiency leading to accumulation of globotriaosylceramide (Gb3) in tissues. Clinical manifestations do not appear to correlate with total Gb3 levels. Studies examining tissue distribution of specific acyl chain species of Gb3 and upstream glycosphingolipids are lacking. MATERIAL & METHODS/RESULTS: Thorough characterization of the Fabry mouse sphingolipid profile by LC-MS revealed unique Gb3 acyl chain storage profiles. Storage extended beyond Gb3; all Fabry tissues also accumulated monohexosylceramides. Depletion of ABCB1 had a complex effect on glycosphingolipid storage. CONCLUSION: These data provide insights into how specific sphingolipid species correlate with one another and how these correlations change in the α-galactosidase A-deficient state, potentially leading to the identification of more specific biomarkers of Fabry disease.