Molecular mechanisms of cholesterol or homocysteine effect in the development of atherosclerosis: Role of vitamin E

α-Tocopherol supplementation and the oxidative stress, homocysteine, and antioxidants in lead exposure

To investigate whether α-tocopherol supplementation in workers exposed to lead would reduce the oxidative stress intensity and decrease homocysteine level, the examined population was randomly divided into two groups. Workers in the first group (n = 49, reference group) were not administered any drugs. Workers in the second group (n = 34) were administered orally α-tocopherol, 200 mg per day for 12 weeks. The level of α-tocopherol significantly increased compared to the baseline and the reference group. The level of thiol groups significantly increased compared to the reference group. However, the levels of malondialdehyde and homocysteine did not significantly change. Animal studies suggest the ability of α-tocopherol administration to reverse adverse health effects of lead exposure, such as oxidative stress; however, the results of this study on humans do not confirm these protective effects.

Plasma and Aorta Biochemistry and MMPs Activities in Female Rabbit Fed Methionine Enriched Diet and Their Offspring

This study investigated whether a high Met diet influences biochemical parameters, MMPs activities in plasma, and biochemical and histological remodeling in aorta, in both pregnant female rabbits and their offspring. Four female rabbit groups are constituted (each n = 8), nonpregnant control (NPC), pregnant control (PC) that received normal commercial chow, nonpregnant Met (NPMet), and pregnant Met (PMet) that received the same diet supplemented with 0,35% L-methionine (w/w) for 3 months (500 mg/d). All pregnant females realize 3 successive pregnancies. Plasma results showed that Met excess increased Hcy, raised CRP in NPMet and decreased it in PMet, enhanced significantly proMMP-2 and proMMP-9 activities in NPMet, and reduced them in PMet. Aorta showed a rise in collagen level, essentially in PMet, a reduction of elastin content in both PMet and NPMet, and a significant decrease in lipid content in PMet, with histological changes that are more pronounced in NPMet than PMet. Met excess enhanced proMMP-9 activities in NPMet while it decreased them in PMet. PMet newborn presented increase in uremia and CRP and significant rise of active MMP-2 and MMP-9 forms. In aorta, media and adventitia thickness increased, total lipids content decreased, proMMP-9 activity decreased, and proMMP-2 activity increased.

The influence of methionine, selenomethionine, and vitamin E on liver metabolic pathways and steatosis in high-cholesterol fed rabbits

Significant disorders of liver metabolic pathways enzymes after high-cholesterol diet could give information on liver steatosis development. This process could probably also be inhibited by some compounds, as examined in rabbits. Forty-two male rabbits were served a high-cholesterol diet (2 g%) (0.67 g/kg b.m./24 h) with addition of d,l-methionine (70 mg/kg b.m./24 h) or seleno-d,l-methionine (12.5 microg/kg b.m./24 h) or alpha-tocopherol (10 mg/kg b.m./24 h) for 3 months to compare the protection effect of used compounds on liver metabolism and steatosis. At the beginning and every month, blood was taken. After the experiment was completed, livers were dissected for histological examinations. The concentration of total cholesterol (t-CH), triacylglycerol (TG), and the activities of aldolase (ALD), sorbitol dehydrogenase (SDH), glutamate dehydrogenase (GLDH), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were determined. Plasma t-CH and TG concentrations were significantly higher in all experimental groups vs control group. Blood serum AST and ALT activities did not undergo change but there were observed not significant increase in the CH group vs control group. Activities of SDH, GLDH, and LDH increased in blood serum and decreased in the liver in all experimental groups. Activities of LDH and SDH increased in the liver in the CH+Met group vs CH group. ALD activity decreased in the liver only in the CH and CH+Se groups. This data support a lipotoxic model of cholesterol-mediated hepatic steatosis. Prolonged administration of high-cholesterol diet not only disturbs the structure of cell membranes, which is expressed by decreased activity of enzymes in the liver and the migration of those enzymes to plasma but as well leads to steatosis of the liver, which has been confirmed by histological examinations. The applied compounds appear to have a varying influence upon the activity of enzymes determined in serum and liver. Obtained results showed a beneficial influence of methionine and vitamin E supplementation on liver steatosis development.

Evaluation of some biological parameters of Opuntia ficus indica. 1. Influence of a seed oil supplemented diet on rats

Cactus pear (Opuntia ficus indica) is native to Tunisia and the fruit is consumed exclusively as fresh fruit. The seed oil is rich in polyunsaturated fatty acids but the nutritive value of the oil is unknown. The objective of our research was to determine the fatty acid content of cactus pear seed oil and to evaluate the effect of an oil supplemented diet on rats. The main fatty acids of prickly pear seed oil were C16:0, C18:0, C18:1, C18:2 with an exceptional level of linoleic acid, up to 700 g kg(-1), and a total content of unsaturated fatty acids of 884.8 g kg(-1). Feed intake and body weight of rats were measured every two days during the nine weeks of treatment. Digestibility, feed conversion efficiency and protein efficiency ratio were determined. No difference in digestibility was noted for the oil enriched diet. The results indicated a significant decrease in serum glucose concentration (22%) over the control group. However, an increase in the concentration of glycogen was noted in liver and muscle. Blood cholesterol and low density lipoprotein (LDL)-cholesterol decreased in the treated group. High density lipoprotein (HDL)-cholesterol concentration remained unaltered during the treatment. These findings support the nutritional value of cactus pear as a natural source of edible oil containing essential fatty acids and reinforce the possibility of cactus pear as a new crop for Tunisia especially in semi-arid regions, where conventional crops are difficult to establish.

Effect of alpha-tocopherol supplementation on blood pressure and lipidic profile in streptozotocin-induced diabetes mellitus in spontaneously hypertensive rats

INTRODUCTION

Antioxidants has been utilized to prevent oxidative damage in diabetes and hypertensive diseases. The current study evaluated the effect of alpha-tocopherol supplementation on blood pressure and the lipid profile in streptozotocin-induced diabetes mellitus in spontaneously hypertensive rats (SHR).

METHODS

The systolic blood pressure and total cholesterol, LDL-cholesterol, HDL-cholesterol and triglycerides were measured in SHR-diabetes induced.

RESULTS

Treatment with alpha-tocopherol (vitamin E) led to a decrease on systolic blood pressure and showed an increase of HDL-cholesterol and a decrease of LDL-cholesterol, but the concentrations of triglycerides and total cholesterol were not changed.

CONCLUSIONS

The vitamin E was able to modulate the blood pressure and the lipidic profile as well, and therefore can be considered as an alternative treatment of lipid disorder found on diabetes and hypertension diseases.