Dn. Mukhin et al., GLYCOSPHINGOLIPID ACCUMULATION IN THE AORTIC-WALL IS ANOTHER FEATURE OF HUMAN ATHEROSCLEROSIS, Arteriosclerosis, thrombosis, and vascular biology, 15(10), 1995, pp. 1607-1615
High accumulation of lipids is a typical feature of an atherosclerotic
lesion. We have previously identified the chemical structure of the m
ajor glycosphingolipids (GSLs) of human aorta; however, quantification
of the absolute concentration of GSLs was not carried out. In the pre
sent study, for the first time we have performed a quantitative compar
ative analysis of GSL composition in the media and two sublayers of th
e intima taken from normal regions, fatty streaks, and atherosclerotic
plaques of the human aorta. The intimal tissue containing fatty strea
ks and atherosclerotic plaques accumulated GSLs, predominantly glucosy
lceramide (GlcCer), lactosylceramide (LacCer), and ganglioside G(M3).
GSL levels in plaques were highest: GlcCer was 18- and 8-fold, LacCer
was 8- and 7-fold, and G(M3) was 2.5- and 12-fold higher than in muscu
loelastic and elastic-hyperplastic intimal layers of normal regions, r
espectively. We did not observe a significant increase in other GSLs.
An increase in the content of gangliosides G(D3) and G(D1a) was detect
ed in the media underlying atherosclerotic lesions. On the basis of an
analysis of the ratio of GlcCer, LacCer, and G(M3); accumulated in th
e tissue and cells of the elastic-hyperplastic layer of intima, we hav
e concluded that the accumulation of the above-mentioned GSLs occurs m
ainly in the extracellular space of the intima. In this study, we have
also demonstrated that extracellular lipid liposomes, which appear in
the early stages of atherogenesis, are one locus of GSL accumulation
in the extracellular space of the intima. The findings suggest that th
e GSL concentration and distribution within the normal and atheroscler
otic aorta reflects a number of factors that include (1) synthesis of
GSLs within the vessel wall, (2) deposition of GSLs within the vessel
wall from plasma-derived lipoproteins, (3) the degree of association o
f the various GSLs with intimal cells as well as extracellular lipid p
articles, and (4) metabolic relationships between cholesterol and GSL
accumulation.