Plasma gangliosides and age‐related macular degeneration

Purpose Age-related macular degeneration (AMD) is a multifactorial and polygenic disease and is the main cause of vision loss in developed countries after 50 years old. Indeed, dry AMD leads to progressive retinal atrophy and exsudative AMD induces a rapid alteration of the macula through neovascularisation. Gangliosides (GG) make a wide and heterogeneous family of sialic-acid-containing glycosphingolipids, composed of a sugar chain branched on a ceramide. They are major components of cellular membranes and are particularly abundant in the brain and nervous tissue, including retina. They are also found circulating in the plasma. GG are known for their neuroprotective properties in the nervous system and retina. The present study aimed to determine whether plasma GG could represent biomarkers of AMD. Methods The study included 90 subjects divided into 3 groups: control, dry AMD and exsudative AMD. For each subject, plasma GG were extracted, purified and analyzed by liquid chromatography coupled to mass spectrometry. Results GM3 appeared to be by far the major GG of human plasma. Small amounts of GD3, GM2, GD1a and GD1b could also be detected, but no specific species could be identified in the plasma of AMD patients. Fifteen molecular species of GM3 were identified accounting for the variability in the ceramide moiety of the GG molecule. Analyses revealed no significant differences in the proportion of the different GM3 species between control, dry and exsudative AMD patient groups. Conclusion Although GG are important for retina’s structure and function, it seems they cannot be used as circulating markers of the retinal damages occurring during the course of AMD.