The relationship between plasma glucose and insulin responses to oral glucose, LDL oxidation, and soluble intercellular adhesion molecule-1 in healthy volunteers.

This study was initiated to describe the relationships between plasma glucose and insulin responses to oral glucose and the concentrations of partially oxidized low density lipoprotein (poxLDL) and soluble intercellular adhesion molecule-1 (sICAM-1) in 23 healthy, non-diabetic volunteers. Results demonstrated that plasma glucose (r=0.65, P<0.002) and insulin (r=0.58, P<0.007) responses to a 75-g oral glucose challenge were highly correlated to poxLDL concentrations. Plasma glucose (r=0.63, P<0.002) and insulin (r=0.68, P<0.001) concentrations also significantly correlated with sICAM-1 concentrations. Furthermore, concentrations of poxLDL and sICAM-1 were significantly related (r=0.55, P<0.001). These relationships remained statistically significant when adjusted for differences in age, gender, body mass index, and lipoprotein concentrations. These results provide further evidence that circulating LDL particles are more highly oxidized in insulin resistant states, and demonstrate the presence of an in vivo relationship between insulin resistance, LDL oxidized state, and sICAM-1 concentrations. These results help explain why soluble forms of adhesion molecules are increased in clinical conditions characterized by insulin resistance, and support the possibility that LDL oxidizability is increased in insulin resistant subjects, and that the increase in sICAM-1 results from stimulation of cellular adhesion molecules by more highly oxidized LDL.