Elier Paz

The apolipoprotein A-IV-360His polymorphism determines the dietary fat clearance in normal subjects

Apolipoprotein IV (apo A-IV) has been related to fat absorption and to the activation of some of the enzymes involved in lipid metabolism. Several polymorphic sites within the gene locus for apo A-IV have been detected. Previous studies have shown that the A-IV-2 isoform produces a different plasma lipid response after the consumption of diets with different fat and cholesterol content. The present study was designed to evaluate whether the apo A-IV 360His polymorphism could explain, at least in part, the interindividual variability observed during postprandial lipemia. Fifty-one healthy male volunteers (42 homozygous for the apo A-IV 360Gln allele (Gln/Gln) and nine carriers of the A-IV-360His allele), homozygous for the apo E3 allele, were subjected to a vitamin A-fat load test consisting of 1 g of fat/kg body weight and 60000 IU of vitamin A. Blood was drawn at time 0 and every hour for 11 h. Plasma cholesterol (C), triacylglycerol (TG), and C, TG, apo B-100, apo B-48, apo A-IV and retinyl palmitate (RP) were determined in lipoprotein fractions. Data of postprandial lipemia revealed that subjects with the apo A-IV 360His allele had significantly greater postprandial levels in small triacylglycerol rich lipoproteins (TRL)-C (P<0.02), small TRL-TG (P<0.01) and large TRL-TG (P<0.05) than apo A-IV 360Gln/Gln subjects. In conclusion, the modifications observed in postprandial lipoprotein metabolism in subjects with the A-IV 360His allele could be involved in the different low density lipoprotein (LDL)-C responses observed in these subjects following a diet rich in cholesterol and saturated fats.

Mediterranean diet improves low density lipoprotein susceptibility to oxidative modifications.

Fundamento Numerosos paneles de expertos, en especial de paises anglosajones, recomiendan la dieta pobre en grasa para la prevencion de enfermedades cardiovasculares. Sin embargo, la tasa de muerte por cardiopatia isquemica es baja en los paises del area mediterranea, lo que puede ser debido al alto porcentaje de grasa monoinsaturada proporcionada por el aceite de oliva en la dieta. Por ello hemos comparado el efecto de ambas dietas sobre la susceptibilidad in vitro a la oxidacion de las lipoproteinas de baja densidad (LDL), pieza clave en el inicio y desarrollo de la arteriosclerosis. Sujetos y metodos Cuarenta y un sujetos varones sanos normolipemicos fueron sometidos a tres periodos de dieta, de 4 semanas de duracion cada uno, consistentes en una dieta rica en grasa saturada (SAT: 38% grasa, 20% saturada), otra pobre en grasa (NCEP-I: 28% grasa, 10% saturada) y una dieta mediterranea (38% grasa, 22% de grasa monoinsaturada). Al final de cada periodo dietetico se determinaron las concentraciones plasmaticas de colesterol total, cLDL, cHDL, trigliceridos, apoproteinas A-I y B, α-tocoferol y la susceptibilidad a la oxidacion de las LDL in vitro. Resultados Ambas dietas hipolipemiantes produjeron un descenso significativo de las concentraciones plasmaticas de colesterol total, cLDL y apo B, mientras que solo la dieta NCEP-I disminuyo el cHDL. La sustitucion de una dieta rica en grasa saturada o de una dieta rica en hidratos de carbono por una dieta mediterranea aumento la resistencia a la oxidacion de las LDL al prolongarse el tiempo de latencia (p Conclusion Nuestros resultados indican que el consumo de una dieta mediterranea rica en aceite de oliva, ademas de mejorar el indice aterogenico (colesterol total/cHDL), aumenta la resistencia a la oxidacion de las LDL en comparacion con la dieta pobre en grasa. Ello nos hace aconsejar el modelo de dieta mediterranea para la prevencion de las enfermedades cardiovasculares.

Effects of feeding virgin olive oil or their polyphenols on lipid of rat liver

Abstract The present study investigated the effects of virgin olive oil and their polyphenols on lipid content of liver, cholesterol metabolism related enzymes of liver microsome and fatty acid composition. Four groups of seven male rats were fed for 5 weeks diets with cholesterol (1%) supplemented with virgin olive oil with or without polyphenols or polyphenols extracted from virgin olive oil. Total cholesterol and phospholipid levels of liver tissu were not affected by either type of diet. However, triacylglycerol levels increased in both animals fed virgin olive oil with or without polyphenols. Furthermore, the activity of HMG-CoA reductase decreased significantly in liver microsome from polyphenols extract-fed group. Cholesterol 7α-hydroxylase was significantly diminished in rats fed virgin olive oil with polyphenols compared to olive oil without polyphenols.