Since
oxidized LDL may play a role in the genesis of
atheroma, which is the primary complication of
non-insulin-dependent diabetes mellitus (
NIDDM), we investigated whether the
LDL of diabetic patients were more prone to oxidation than those of healthy controls. We therefore studied the susceptibility of
LDL to oxidation by
phenylhydrazine (
LDL-PO) in
NIDDM patients with or without macroangiopathy, and in controls. Results showed that the
LDL of patients with macroangiopathy (n = 50) were more susceptible to oxidation than those of both
NIDDM patients without vascular complications (n = 50) and controls (n = 50). In diabetic patients, there was a positive correlation between
LDL-PO and the following parameters: total
cholesterol,
triglycerides,
LDL cholesterol,
apolipoprotein B. In contrast, there was no correlation between
LDL-PO and the parameters of
glycemic control (fasting
glucose, HbAlc). After analyzing the composition of
LDL, it appeared that
LDL-PO values in diabetic patients were positively correlated with those of all
LDL constituents. The increase in
LDL-PO observed in the group of
NIDDM patients with macroangiopathy could be a consequence of an increase in the
LDL triglyceride content in these patients.