Age-related changes in the lateral lipid distribution in a human lens described by mass spectrometry imaging.

The lateral lipid distribution in eye lenses of three human donors were studied by matrix-assisted laser desorption ionization imaging mass spectrometry using a high mass resolution. By using exact mass measurements this study shows the relationship between the aging process and the number of lipids detected as well as between aging and the abundance of products derived from sphingomyelins by hydrolysis. Variable lipid composition was also observed in the nuclear, barrier, or cortex regions of the lens samples. This is the first study that suggests the distribution of lysolipids as a potential biomarker panel for the aging of human lens tissue.

Fabry disease: renal sphingolipid distribution in the α-Gal A knockout mouse model by mass spectrometric and immunohistochemical imaging.

Fabry disease is an X-linked lysosomal storage disease due to deficient α-galactosidase A (α-Gal A) activity and the resultant lysosomal accumulation of globotriaosylceramide (Gb3) and related lipids primarily in blood vessels, kidney, heart, and other organs. The renal distribution of stored glycolipid species in the α-Gal A knockout mouse model was compared to that in mice to assess relative distribution and absolute amounts of accumulated sphingolipid isoforms. Twenty isoforms of five sphingolipid groups were visualized by mass spectrometry imaging (MSI), and their distribution was compared with immunohistochemical (IHC) staining of Gb3, the major stored glycosphingolipid in consecutive tissue sections. Quantitative bulk lipid analysis of tissue sections was assessed by electrospray ionization with tandem mass spectrometry (ESI-MS/MS). In contrast to the findings in wild-type mice, all three analytical techniques (MSI, IHC, and ESI-MS/MS) revealed increases in Gb3 isoforms and ceramide dihexosides (composed mostly of galabiosylceramides), respectively. To our knowledge, this is the first report of the distribution of individual molecular species of Gb3 and galabiosylceramides in kidney sections in Fabry disease mouse. In addition, the spatial distribution of ceramides, ceramide monohexosides, and sphingomyelin forms in renal tissue is presented and discussed in the context of their biosynthesis.