title: Glycoxidized LDL increases lectin-like oxidized low density lipoprotein receptor-1 in diabetes mellitus.
abstract: OBJECTIVE
  LDL is subjected to glycoxidation in diabetes mellitus. We have evaluated the effect of glycoxidized LDL on lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) expression in endothelial cells in vitro, as well as the relationship between glycoxidzied LDL and LOX-1 in type 2 diabetic patients with and without microalbuminuria in vivo.
  
  
  METHODS
  Endothelial cells were incubated with modified LDL including glycoxidized LDL, oxidized LDL (oxLDL), glycated LDL, and acetylated LDL, and cellular LOX-1 and the soluble forms of LOX-1 (sLOX-1) in cell medium was measured. Glycoxidized LDL in diabetic patients was determined by measuring the glycoxidation product N(epsilon)-(carboxymethyl)lysine (CML) in apolipoprotein (apo) B. Serum oxLDL and sLOX-1 was determined by ELISA.
  
  
  RESULTS
  Only glycoxidized LDL and oxLDL significantly increased LOX-1 expression (p<0.05) and the production of sLOX-1 (p<0.05), and the effect of glycoxidized LDL was greater than that of oxLDL. Both normoalbuminuric (n=110) and microalbuminuric (n=91) patients had higher serum apoB-CML than controls (n=105) (p<0.01), but oxLDL was only elevated in the microalbuminuric patients (p<0.05). Serum sLOX-1 was significantly increased in both groups of patients compared to controls (p<0.01). Serum sLOX-1 correlated with apoB-CML (r=0.36, p<0.001) but not with oxLDL. The relationship between sLOX-1 and apoB-CML was independent of HbA1c, age, gender, BMI and smoking status.
  
  
  CONCLUSIONS
  Glycoxidized LDL was more potent than oxLDL in inducing LOX-1 in vitro. Serum concentration of apoB-CML, a marker of glycoxidized LDL, was increased in type 2 diabetic patients with and without microalbuminuria, and this was associated with an increase in serum sLOX-1.
authors.affiliation: Department of Medicine, University of Hong Kong, Queen Mary Hospital, Hong Kong.
authors.forename: Sammy W M
authors.initials: SW
authors.lastname: Shiu
authors.forename: Kathryn C B
authors.initials: KC
authors.lastname: Tan
authors.forename: Ying
authors.initials: Y
authors.lastname: Wong
authors.forename: Lin
authors.initials: L
authors.lastname: Leng
authors.forename: Richard
authors.initials: R
authors.lastname: Bucala