RESUMO
In humans, the age of fibre cells differs across the ocular lens, ranging from those formed before birth in the core of the lens to those formed just prior to death in the outer cortex. The distribution of glycerophospholipids in the adult human lens should reflect this range; however, limited data currently exists to confirm this hypothesis. Accordingly, this study aimed to determine the distribution of glycerophospholipids in adult human lens using mass spectrometry imaging. To achieve this, 20-µm thick slices of two human lenses, aged 51 and 67 were analysed by matrix-assisted laser desorption ionisation imaging mass spectrometry. The data clearly indicate that intact glycerophospholipids such as phosphatidylethanolamine, phosphatidylserine, and phosphatidic acid are mainly present in the outer cortex region, corresponding to the youngest fibre cells, while lyso-phosphatidylethanolamine, likely produced by the degradation of phosphatidylethanolamine, is present in the nucleus (older fibre cells). This study adds further evidence to the relationship between fibre cell age and glycerophospholipid composition.
Assuntos
Glicerofosfolipídeos/metabolismo , Cristalino/metabolismo , Adulto , Idoso , Linhagem da Célula/genética , Glicerofosfolipídeos/genética , Glicerofosfolipídeos/isolamento & purificação , Humanos , Cristalino/diagnóstico por imagem , Lisofosfolipídeos/química , Lisofosfolipídeos/isolamento & purificação , Lisofosfolipídeos/metabolismo , Pessoa de Meia-Idade , Fosfatidiletanolaminas/química , Fosfatidiletanolaminas/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
The lipidome of the human lens is unique in that cholesterol and dihydrosphingomyelin are the dominant classes. Moreover, the lens lipidome is not static with dramatic changes in several sphingolipid classes associated with both aging and cataract. Accordingly, there is a clear need to expand knowledge of the molecular species that constitute the human lens sphingolipidome. In this study, human lens lipids have been extracted and separated by thin-layer chromatography (TLC). Direct analysis of the TLC plates by desorption electrospray ionisation-mass spectrometry (DESI-MS) allowed the detection over 30 species from 11 classes of sphingolipids. Significantly, novel classes of lens lipids including sulfatides, dihydrosulfatides, lactosylceramide sulfates and dihydrolactosylceramide sulfates were identified.