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From Serlia et INSERM U325-1 rue du Professeur Calmette, Institut Pasteur de Lille, Lille, France (B.I., G.C., V.C., J.C.F.); INSERM U42 - Certia, Villeneuve d'Ascq, France (C.S.);. Centre Hospitalier de Douai, Douai, France (R.B.); and Service de Diabétologie, Chu de Nancy et CIC INSERM du Chu de Nancy, Nancy, France (P.D.).
Correspondence to Catherine Fiévet, Serlia et INSERM U325-1 rue du Professeur Calmette, Institut Pasteur de Lille, 59019 Lille, France.
Abstract This study compared the structural and functional properties of glucosylated and non-glucosylated LpA-I particle subfractions (GLpA-I and NGLpA-I, respectively) isolated from patients with poorly controlled type 1 (insulin-dependent) diabetes. Compared with NGLpA-I, GLpA-I showed an enrichment in triglycerides (P<.05) and a depletion in phospholipid (P<.05) content. Moreover, the triglycerides-to-cholesteryl esters ratio was increased (P<.05), suggesting an increased cholesteryl ester transfer protein activity and a possible transport defect that accelerates atherogenesis. The surface-to-core constituents ratio, an indirect estimate of particles size, is lower in GLpA-I (P<.01) than in NGLpA-I, correlating well with a larger median size (P<.05) as seen by electron microscopy. The apolipoprotein (apo) A-I conformation was evaluated through determination of the immunological accessibility of three different domains defining specific epitopes for anti-apo A-I monoclonal antibodies. We observed a marked decreased accessibility for two of these regions, which interestingly have already been implicated in the interaction with cells. Cell culture data suggest that nonenzymatic glycosylation occurring on apo A-I can modify lipoprotein function, since it results in a decreased binding of GLpA-I to HeLa cells and impaired cholesterol efflux from Fu5AH rat hepatoma cells.
Key Words: glucosylation LpA-I lipoprotein particles reverse cholesterol transport atherosclerosis
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