Israel Medical Association Journal

Objective: To examine the effect of aspirin administration (low dosage) on the susceptibility of LDL to oxidative modification healthy volunteers.

Methods: Aspirin 75 mg was administered daily for 2 weeks to 10 healthy volunteers selected from the medical staff and students at the faculty of medicine. The main outcome measure was ex vivo oxidation of LDL by ultraviolet C irradiation or by peroxyl free redicals generated by AAPH (2,2’ -azobis 2-amidinopropane hydrochloride). The extent of LDL oxidation was determined by measuring the formed amounts of thiobarbituric-acid reactive substances, lipid peroxides and conjugated dienes.

Results: Following exposure to UV_C irradiation there was a significant (p<0.01) increase (10.8%) in TBARS concentrations and a significant (p≤0.05) increase (5.4%) in PD concentrations in LDL withdrawn after aspirin treatment as compared to LDL withdrawn before aspirin treatment. Following incubation with AAPH there was a significant (p<0.05) increase (15%) in PD concentrations and a significant (p<0.05) reduction (10%) of the LDL oxidation lag time in LDL withdrawn after aspirin intake as compared to LDL withdrawn before aspirin treatment.

Conclusions: Aspirin treatment given to healthy volunteers at a dose of 75 mg/day increased the susceptibility of their plasma LDL to oxidative modification ex vivo. Our study provides, for the first time, in vivo evidence of pro-oxidative properties of aspirin already suggested by previous in vitro trials.

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[1] 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.