Antithrombotic potential of olive oil administration in rabbits with elevated cholesterol.

Olive oil is the main source of dietary fatty acids in the Mediterranean region. The objective of this study was to evaluate the effect of dietary supplementation with virgin olive oil in an experimental model with rabbits fed an atherogenic diet (saturated fat 48% of total fat). Four different groups of 10 animals each were studied: (1) normolipemic diet (NLD), (2) atherogenic diet or saturated fatty acid-enriched diet (SFAED), (3) NLD with 15% olive oil (NLD+OLIV), and (4) SFAED with 15% virgin olive oil (SFAED+OLIV). The animals were fed the experimental diets for 6 weeks, after which we determined serum lipid profile (total cholesterol, HDL-cholesterol, and triglycerides), platelet aggregation, platelet thromboxane B(2), aortic prostacyclin, and platelet and vascular lipid peroxidation. Scanning electron microscopic images of the vascular endothelium were studied, as were morphometric parameters in the arterial wall and thrombogenicity of the subendothelium (annular perfusion chamber). Animals fed the SFAED showed platelet hyperactivity and increased subendothelial thrombogenicity. Animals fed the SFAED+OLIV showed, compared with the SFAED group, an improved lipid profile with decreased platelet hyperactivity and subendothelial thrombogenicity and less severe morphological lesions of the endothelium and vascular wall. We conclude that supplementation of the SFAED with 15% olive oil reduced vascular thrombogenicity and platelet activation in rabbits. Although the percentage of olive oil in the diet was higher than the amount in the human diet, these results may be helpful in determining the effect of olive oil in the human thrombogenic system.

Effect of S-adenosyl-L-methionine on rat brain oxidative stress damage in a combined model of permanent focal ischemia and global ischemia-reperfusion.

We analyzed the effects of S-adenosyl-L-methionine (SAM) on tissue oxidative status in a combined model of permanent focal ischemia and global reperfusion in the rat brain. The production of thiobarbituric acid reactive substances (TBARS) was measured under basal conditions and after induction with ferrous salt as an indicator of brain lipid peroxidation. Total, oxidized and reduced glutathione were measured as indicators of the antioxidant defense capacity of brain tissue. Mitochondrial reduction of tetraphenyl tetrazolium (TPT) was quantified morphometrically. Results obtained in vitro showed that incubation with SAM reduced lipid peroxidation, with a maximum inhibition of 65.12+/-5.99% after incubation with 1 mmol/l; glutathione production was not significantly modified. In the brain ischemia-reperfusion model, TBARS production increased and glutathione content decreased, and mitochondrial reduction of TPT decreased significantly after ischemia-reperfusion in areas dependent on carotid circulation. The administration of 50 mg/kg SAM per day for 3 days led to the inhibition of brain lipid peroxidation and increased total glutathione production. These changes were accompanied by an increase in mitochondrial capacity to reduce TPT. We conclude that SAM reduces oxidative damage in the rat brain in an experimental model of ischemia-reperfusion.

Effect of dietary supplementation with evening primrose oil on vascular thrombogenesis in hyperlipemic rabbits.

The dietary intake of saturated fatty acids affects arteriosclerosis. We studied the effect of supplementation (15% wt/wt) of a hyperlipemic diet (1.3% cholesterol) with evening primrose oil (Oenothera biennis) in four groups of 10 rabbits each. After 6 weeks the aortic endothelium was analyzed morphologically with scanning electron microscopy, and the arterial wall was studied with morphometric techniques and cell nucleus counts. Endothelial functioning was analyzed by measuring prostacyclin synthesis, and thrombogenicity of the subendothelium was studied by perfusion in a Baumgartner annular chamber. Evening primrose oil reduced hypercholesterolemia (from 29 +/- 3 to 12 +/- 2 nmol/l), increased HDL-cholesterol (from 0.5 +/- 0.06 to 0.8 +/- 0.09 nmol/l) and doubled prostacyclin synthesis (from 2.7 +/- 2 to 6.2 +/- 0.7 ng/mg aorta) in rabbits on the hyperlipemic diet, reduced subendothelial surface occupied by platelets (from 6.9 +/- 0.4 to 4.8 +/- 0.3%), and reduced human platelet adhesion on the subendothelium (from 53.3 +/- 6% to 38 +/- 8%, respect to total occupation). Morphological analyses showed that evening primrose oil diminished endothelial lesions caused by the atherogenic diet, reducing area of the arterial wall (from 6.9 +/- 0.2 to 4.7 +/- 0.2 microm2 x 10(6)) and the degree of neointimal proliferation (from 0.6 +/- 0.02 to 0.4 +/- 0.09 microm2 x 10(6)). We conclude that in our experimental model, this dietary supplement enhanced the antithrombotic capacity of the endothelium, reduced subendothelial thrombogenicity, and diminished the extent of vascular wall lesions caused by the hyperlipemic diet.

Effects of triflusal and its main metabolite HTB on platelet interaction with subendothelium in healthy volunteers.

The ex vivo effect of triflusal and acetylsalicylic acid (ASA) on platelet interaction with the subendothelium using the Baumgartner perfusion system (wall shear rate 350 s-1) was assessed in blood from 10 healthy volunteers who given a 15-day course of triflusal 600 mg per day and ASA 400 mg per day in a cross-over trial. The percentage of platelets on the subendothelium showed a decrease of 62% in samples from subjects on ASA and a decrease of 93% in those from subjects on triflusal (P < 0.005). The percentage of the subendothelial surface covered by platelets was reduced by 23.3% after treatment with ASA, mainly due to inhibition of aggregates (75.2%), and by 29.9% after treatment with triflusal, mainly due to inhibition of aggregates (89.6%) and of adhesion (25%). The subendothelial surface covered by activated platelets (adhesions and thrombi) showed 32.5% inhibition after treatment with triflusal and 11.6% after treatment with ASA (P < 0.043 vs. triflusal). In the in vitro experiments, 10 mumol.l-1 triflusal did not modify the percentage of the subendothelium covered by platelets. HTB 1 mmol.l-1 inhibited adhesion (26%) and aggregates (18%). We conclude that HTB participates in the ex vivo effects of triflusal on the platelet-subendothelium interaction.

Effects of alpha-tocopherol on lipid peroxidation and mitochondrial reduction of tetraphenyl tetrazolium in the rat brain.

The antioxidant effect of alpha-tocopherol was assessed in a model of ischemia-reperfusion in the rat brain. In this model, permanent ischemia of the cortical branches of the middle cerebral artery was combined with bilateral occlusion of the common carotid arteries for 1 h and restoration of circulation for a period of 2 h. Lipid peroxidation and mitochondrial reduction of tetraphenyl tetrazolium (TPT) were determined in both untreated and d-alpha-tocopherol treated rats. Ferrous sulfate and ascorbic acid (FeAs) were used to induce lipid peroxidation via the formation of hydroxyl anions. Malondialdehyde (MDA) increased in the ischemia-reperfusion areas (+101%), but FeAs-induced MDA did not vary in the area of permanent ischemia. Brain tissue undergoing ischemia-reperfusion was about 50% less sensitive to the antioxidant effect of ascorbic acid. The reduction of TPT showed 52% mitochondrial damage in the area of ischemia-reperfusion, whereas mitochondrial activity in the area of permanent ischemia was 177 times lower as compared to controls. d-alpha-tocopherol caused a 40% inhibition of MDA production and 16.5% and 21.5% decrease in mitochondrial activity in the areas of ischemia-reperfusion and permanent ischemia, respectively.

Developmental qualitative and quantitative aspects of the subependymal layer from the caudato-pallial angel of the rat lateral ventricles.

We have studied by both qualitative and quantitative methods the subependymal cells in the caudato-pallial angle (CPA) of the lateral ventricle from 1, 2, 6 and 18 month-old rats. We have chosen the CPA, among other zones, because it is an easily delimited glial proliferative zone. The qualitative analysis was carried out using both Klüver-Barrera and Luxol-Fast-Blue stains. The quantitative study was carried out by a semiautomatized image analysis system. Three types of subependymal nuclei were classified by Klüver-Barrera stain, according to the following parameters: staining intensity, morphology and size. Each of the three type groups was found at different frequency depending of rat age. Luxol-Fast-Blue stained mitotic images in metaphase or anaphase: n = 38 in the 1 month, n = 49 in 2 months, n = 12 in the 6 months, and n = 5 in the 18 month-old rats. The quantitative analysis (length, areas and volume of CPA) were in agreement with the above data, showing a more subependymal activity in the 2 month-old animals than in the 1, 6 and 18 month-old rats.

The pyrimido-pyrimidine derivative RA-642 protects from brain injury in a combined model of permanent focal ischemia and global ischemia reperfusion.

The effects of pyrimido-pyrimidine derivatives (dipyridamole, RA-642 and mopydamole) on lipid peroxidation (inhibition of the production of malondialdehyde, MDA) in different regions of the rat brain were studied. Ferrous sulfate and ascorbic acid (FeAs) were used to induce lipid peroxidation via the formation of hydroxyl anions. The antiperoxidative effect of RA-642 (in the microM range) was 10 times more potent than that of dipyridamole. Mopydamole did not exert any inhibitory effect on MDA production. In a model of ischemia reperfusion with bilateral occlusion of the common carotid arteries for 1 h and restoration of circulation for a period of 2 h, dipyridamole inhibited FeAs-induced MDA production but did not protect from postischemic brain tissue damage (measured by mitochondrial reduction of tetraphenyl tetrazolium). RA-642 inhibited FeAs-induced MDA production and showed 50-67% protection from tissue damage as compared with untreated animals, while mopydamole did not inhibit MDA production and showed 30-48% protection. No correlation was found between inhibition of lipid peroxidation and protection from brain tissue damage.

Morphological aspects of ferrous salts-induced lipid peroxidation and platelet aggregation in human blood.

This is a study of the effect that reactive oxygen species (ROS) have on blood platelet aggregation, lipid peroxidation and external morphology (scanning electron microscopy) of human platelets. The induction of ROS was brought about by the incubation of ferrous salts. The production of ROS produced a state of morphological preactivation without actually producing platelet aggregation, while the joint incubation of the ferrous salts with threshold concentrations of arachidonic acid produced an increase of the latter, causing complete platelet aggregation, biochemically as well as morphologically.