Search results for "lipids"

Intestinal CD36. A lipid-sensor involved in the processing of chylomicrons in rodents

2011

International audience; CD36 is a multifunctional glycoprotein which binds nanomolar concentrations of long-chain fatty acids (LCFA) and is highly expressed on the luminal surface of enterocytes. Despite of its implication in oleoylethanolamide (OEA) and chylomicron synthesis, CD36 function in small intestine remains incompletely understood. Our in vivo data demonstrated that CD36 gene deletion in mice did not affect intestinal LCFA uptake. CD36 protein disappeared early from the luminal side of intestinal villi during the post-prandial period but only when the diet contained lipids. This drop was significant 1 h after a lipid supply and was associated with ubiquitination of CD36. Using CHO…

Fatty acid composition of french butters, with special emphasis on conjugated linoleic acid (CLA) isomers

2005

Conjugated linoleic acids (CLA) are fatty acids primarily found in dairy products. These fatty acids may have potential biological properties interesting for human health. Update of French food composition data banks was needed to determine CLA levels in French dairy products and to evaluate CLA intake by the French population. As part of this investigation, we analyzed 54 butters from local producers at different times of the year. The average CLA levels in butter were 0.45 g CLA/100 g butter in winter, 0.58 in spring, and 0.80 in summer. Regional variations of CLA levels in butters were observed from different producing areas in France. Butters from hill and mountain regions, and butters …

Association of liver steatosis with lipid oversecretion and hypotriglyceridaemia in C57BL/6j mice fed trans-10, cis-12-linoleic acid

2003

AbstractConjugated linoleic acids (CLA) have recently been recognized to reduce body fat and plasma lipids in some animals. This study demonstrated that the steatosis accompanying the fat loss induced by trans-10,cis-12-C18:2 (CLA2) and not cis-9,trans-11-C18:2 (CLA1) isomer in C57BL/6j mice was not due to an alteration of the liver lipoprotein production that was even increased. The 3-fold decrease in plasma triacylglycerol contents and the induction of mRNA expression of low-density lipoprotein receptors concomitantly observed in CLA2-fed mice suggested an increase in the lipoprotein clearance at the level of the liver itself. CLA1 feeding produced similar but attenuated effects on trigly…

Comparative effects of equivalent intakes of 18:3 (n-3) and of marine (n-3) fatty acids on rat cardiac phospholipid contents and fatty acid compositi…

1990

Abstract Three groups of male Sprague-Dawley rats were fed for 4 weeks purified diets containing 15% by weight of oil mixtures varying in the nature and content of (n-3) polyunsaturated fatty acids (PUFA) but supplying similar levels of 18:2 (n-6) (10% of the total dietary fatty acids) and of saturated fatty acids (19% of the total fatty acids). The First diet (“Low 18:3”) contained small amounts of 18:3 (0.5% of the total fatty acids), the second (“18:3”) contained linolenic acid (10% of the total fatty acids) as the only source of (n-3) PUFA and the third one (“LC (n-3)”) contained the same amount of long chain (n-3) PUFA (mainly 20:5 and 22:6). Heart phospholipid classes were separated b…

The implication of omega-3 polyunsaturated fatty acids in retinal physiology

2007

International audience; Neuronal tissues such as the retina and the brain are characterized by their high content in phospholipids. In the retina, phospholipids can account for until 80% of total lipids and are mainly composed by species belonging to phosphatidyl-choline and phosphatidyl-ethanolamine sub-classes. Within fatty acids esterified on retinal phospholipids, omega-3 PUFAs are major components since docosahexaenoic acid (DHA) can represent until 50% of total fatty acids in the photoreceptor outer segments.For long time, DHA is known to play a major role in membrane function and subsequently in visual processes by affecting permeability, fluidity, thickness and the activation of mem…

trans-C18: 1 Isomers in Cheeses Enriched in Unsaturated Fatty Acids and Manufactured with Different Milk Fat Globule Sizes

2008

International audience; Increasing the knowledge on dietary fat composition, mainly the minor components, will improve the nutritional value of foods and their labeling. In this study, we examined the trans-octadecenoic acid (C18:1) composition of Emmental cheeses enriched in unsaturated fatty acids (FA) and manufactured with milks produced by cows selected to produce small and large fat globules. The FA composition of the milks was not significantly (P > 0.05) different from the FA composition of the corresponding Emmental cheeses. Increasing the unsaturated FA content of the cheeses using dietary manipulations lead to an increase in the trans-C18:1 and changed their isomeric profiles. In …

Stability of Asymmetric Lipid Bilayers Assessed by Molecular Dynamics Simulations

2009

The asymmetric insertion of amphiphiles into biological membranes compromises the balance between the inner and outer monolayers. As a result, area expansion of the receiving leaflet and curvature strain may lead to membrane permeation, shape changes, or membrane fusion events. We have conducted both atomistic and coarse-grained molecular dynamics simulations of dipalmitoyl-phosphatidylcholine (DPPC) bilayers to study the effect of an asymmetric distribution of lipids between the two monolayers on membrane stability. Highly asymmetric lipid bilayers were found to be surprisingly stable within the submicrosecond time span of the simulations. Even the limiting case of a monolayer immersed in …

Direct Observation of Nanometer-Scale Pores of Melittin in Supported Lipid Monolayers

2015

Melittin is the most studied membrane-active peptide and archetype within a large and diverse group of pore formers. However, the molecular characteristics of melittin pores remain largely unknown. Herein, we show by atomic force microscopy (AFM) that lipid monolayers in the presence of melittin are decorated with numerous regularly shaped circular pores that can be distinguished from nonspecific monolayer defects. The specificity of these pores is reinforced through a statistical evaluation of depressions found in Langmuir-Blodgett monolayers in the presence and absence of melittin, which eventually allows characterization of the melittin-induced pores at a quantitative low-resolution leve…

Endogenous peroxynitrite modulates PGHS-1–dependent thromboxane A2 formation and aggregation in human platelets

2008

Aggregation of activated platelets is considerably mediated by the autocrine action of thromboxane A2 (TxA2) which is formed in a prostaglandin endoperoxide H2 synthase-1 (PGHS-1 or COX-1)-dependent manner. The activity of PGHS-1 can be stimulated by peroxides, an effect termed "peroxide tone", that renders PGHS-1 the key regulatory enzyme in the formation of TxA2. Activated platelets release nitric oxide (*NO) and superoxide (O*2) but their interactions with the prostanoid pathway have been controversially discussed in platelet physiology and pathophysiology. The current study demonstrates that endogenously formed peroxynitrite at nanomolar concentrations, originating from the interaction …

2019

Abstract Background Physical activity and dietary intake of dairy products are associated with improved metabolic health. Dairy products are rich with branched chain amino acids that are essential for energy production. To gain insight into the mechanisms underlying the benefit of the sub-chronic effects of running and intake of milk protein supplements, we studied L ow C apacity R unner rats (LCR), a rodent exercise model with risk for metabolic disorders. We especially focused on the role of Sirtuins, energy level dependent proteins that affect many cellular metabolic processes. Methods Forty-seven adult LCR female rats sedentary or running voluntarily in wheels were fed normal chow and g…