Background: Increased levels of high density lipoprotein (over 60 mg/dl) are considered to be a risk factor for ischemic heart disease. However, some patients with high HDL still develop cardiovascular diseases.
Objective: To find out why patients with very high HDL still suffer from cardiovascular diseases.
Methods: We analyzed several risk factors, such as increased lipid peroxidation, hyperhomeocysteinemia and increased release of inflammatory molecules that could be related to the development of vascular disease in patients with high serum HDL levels. Patients with HDL cholesterol levels above 75 mg/dl were selected for this study and were separated into two groups based on the presence of atherosclerotic vascular disease, i.e., those with vascular disease (patients) and those without (controls).
Results: Plasma isolated from the patient group exhibited significantly increased lipid peroxidation by 21% and decreased total antioxidant status by 17%, but there were no differences regarding their serum or their paraoxonase activity. Moreover, both groups exhibited similar levels of serum C-reactive protein, fibrinogen and homocysteine, enabling us to eliminate these risk factors in the etiology of cardiovascular disease in the patient group.
Conclusion: Increased oxidative stress could be one of the factors leading to cardiovascular diseases in patients with high serum HDL levels.