Comparison of the effects of dietary saturated, mono-, and n-6 polyunsaturated fatty acids on blood lipid profile, oxidant stress, prostanoid synthesis and aortic histology in rabbits.

BACKGROUND/AIMS: To compare the effects of saturated, monounsaturated and polyunsaturated n-6 fatty acid-enriched diets on the development of atherosclerosis and thrombosis in New Zealand white male rabbits, 3- to 6-month-old animals were supplemented daily (10 g/100 g diet) with butter (n = 8), olive oil (n = 8) or corn oil (n = 8) by oral administration for 7 weeks. METHODS: Total cholesterol (TC), HDL- (HDL-C) and LDL-cholesterol (LDL-C), triglycerides (TG), apolipoprotein A-1 (ApoA-1), apolipoprotein B (ApoB), lipid peroxides as thiobarbituric acid-reactive substances (TBARS), thromboxane B2 (TXB2) and 6-ketoprostaglandin F(1alpha) (6-ketoPGF(1alpha)) concentrations were determined in blood samples drawn before and after each group was fed the different dietary regimens. Histological examination was performed on the aortic tissues. RESULTS: After 7 weeks, TC, ApoB and TXB2 increased significantly (p < 0.05) in the butter-fed animals compared to pre-experimental concentrations. Olive oil administration lead to a significant (p < 0.05) decrease in TC and ApoB levels. The corn oil-enriched diet decreased TC, LDL-C concentrations, TC/HDL-C ratios and 6-ketoPGF(1alpha) (stable metabolite of prostacyclin-PGI2; p < 0.05 for all) but increased TBARS levels and TXB2/6-ketoPGF(1alpha) ratios. Light microscopic findings were in accordance with these biochemical alterations. CONCLUSION: Although effective in lipid lowering, corn oil increased oxidant stress as evidenced by increased TBARS and induced endothelial damage which lead to a reduction in PGI2 synthesis and consequently to an increase in the TXB2/6-ketoPGF(1alpha) ratio. Olive oil administration did not induce oxidant stress and it had no affect on PGI2 and TXB2 levels which are implicated in platelet aggregation. These findings suggest that oleic acid is more effective than linoleic acid in the protection of endothelial integrity.

Effect of endovascular treatment on nitric oxide and renal function in Takayasu's arteritis with renovascular hypertension.

BACKGROUND: Renal involvement in Takayasu's arteritis (TA) effects the disease outcome and endovascular treatment is an effective treatment of choice. We investigated nitric oxide (NO) levels and the effect of endovascular treatment in renovascular hypertensive TA patients. METHODS: In five hypertensive patients with renal artery stenosis due to TA, serum creatinine, nitrite, nitrate; urinary microalbumin, nitrite, nitrate measurements and blood pressures were recorded at entry and after 24 h and 6 weeks of endovascular treatment. RESULTS: Serum NO levels were higher in patients than controls (p = 0.008). Serum and urine NO levels increased 24 h after the treatment and decreased after 6 weeks (p = 0.015; p = 0.01, respectively). After the treatment blood pressures decreased. Urinary microalbumin excretions increased after the intervention (p = 0.02) and returned to normal in patients 1 and 4, and decreased in the others. There were no significant differences in estimated glomerular filtration rate (EGFR), serum creatinine, urinary sodium and potassium levels. CONCLUSION: Increased NO secretion in these patients may contribute to improve the prognosis of renal function through its vasodilator and antiproliferative activities possibly by counterbalancing the excessive vasoconstrictor actions. Endovascular treatment causes a dilatation-induced shear stress that may be responsible for the increased NO release, which in turn leads to the rapid hypotensive response.