Copper-induced low density lipoprotein oxidation is not a risk discriminator for intermittent claudication

Oxidative modification of low density lipoprotein (LDL) is supposed to be important in atherogenesis. Recently it was shown that subjects with coronary atherosclerosis have an increased susceptibility of their LDL to copper-induced oxidation. We investigated if patients with intermittent claudication (IC) might have an increased susceptibility of LDL to copper-induced oxidation. Fifty-eight males were randomly selected from an epidemiological study of IC, 29 with IC and 29 healthy controls matched for age, sex and smoking habits. All subjects performed a standard exercise test to confirm or exclude peripheral atherosclerosis. Claudicants had a lag phase of 99.7 +/- 14.8 minutes (mean +/- SD) and in healthy controls it was 104.6 +/- 12.9 minutes. The difference between the groups was not significant and neither was there any association between lag phase and degree of peripheral atherosclerosis in IC. Lag phase showed a positive and significant correlation to the plasma concentration of high density lipoprotein-2 (HDL2-) cholesterol. The correlation for the whole group was r = 0.41, p < 0.01. We conclude that the susceptibility of LDL to copper-oxidation does not discriminate between claudicants and healthy controls. The results also suggest that high plasma concentrations of HDL2-cholesterol may have a protective effect on LDL against oxidation.