Search results for "chylomicron"

From fatty-acid sensing to chylomicron synthesis: Role of intestinal lipid-binding proteins

2013

International audience; Today, it is well established that the development of obesity and associated diseases results, in part, from excessive lipid intake associated with a qualitative imbalance. Among the organs involved in lipid homeostasis, the small intestine is the least studied even though it determines lipid bioavailability and largely contributes to the regulation of postprandial hyperlipemia (triacylglycerols (TG) and free fatty acids (FFA)). Several Lipid-Binding Proteins (LBP) are expressed in the small intestine. Their supposed intestinal functions were initially based on what was reported in other tissues, and took no account of the physiological specificity of the small intes…

Diagnostic algorithm for familial chylomicronemia syndrome

2016

International audience; Background: Familial chylomicronemia syndrome (FCS) is a rare genetic disease that leads to severe hypertriglyceridemia often associated with recurrent episodes of pancreatitis. The recognition and correct diagnosis of the disease is challenging due to its rarity, and to the lack of specificity of signs and symptoms. Lipid experts, endocrinologists, gastroenterologists, pancreatologists, and general practitioners may encounter patients who potentially have FCS. Therefore, cooperation between experts and improved knowledge of FCS is essential in improving the diagnosis. Currently, a consensus on best practice for the diagnosis of FCS is lacking. Methods: Aiming to def…

SHORT APOB TRUNCATIONS SHOW IMPAIRE CHYLOMICRON EXPORT AND ENTEROCYTE TRIGLYCERIDE ACCUMULATION. IN VIVO AND IN VITRO EVIDENCE ON A APOB 28.25 STABLE…

2007

Hypobetalipoproteinemia

2011

Hypobetalipoproteinemias (HBL) represent a heterogeneous group of disorders characterized by reduced plasma levels of total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (apoB) below the 5th percentile of the distribution in the population. HBL are defined as primary or secondary according to the underlying causes. Primary monogenic HBL are caused by mutations in several known genes (APOB, PCSK9, MTP, SARA2) or mutations in genes not yet identified. Familial hypobetalipoproteinemia (FHBL) is the most frequent monogenic form of HBL with a dominant mode of inheritance. It may be due to loss-of-function mutations in APOB or, less frequently, in PCSK9 genes.…

Intestinal CD36 : A long chain fatty acid receptor which controls post prandial hypertriglyceridemia, endotoxemia and intestinal epithelium integrity

2014

Post prandial hypertriglyceridemia represents a risk factor for cardio-vascular diseases and it is associated with metabolic syndrom, obesity, and insulino-resistance. The intestine influences lipid bioavailibility and post prandial hypertriglyceridemia. It controls the quantity and the quality of secreted chylomicrons by adapting its metabolism according to the lipid content of the diet. Nevertheless, the mechanism of dietary lipid detection by the enterocyte is not understood. Our work demonstrates that the transmembrane glycoprotein CD36 is a Long Chain Fatty Acid (LCFA) receptor which triggers ERK1/2 activation. This activation is responsible for the induction of mRNA rate of 3 key prot…

Variations of lipid and apolipoprotein content in lipoproteins during fasting in European sea bass (Dicentrarchus labrax L.)

1997

Lipoproteins are involved in transport of exogenous and endogenous lipids. For this reason, the lipoprotein pattern undergoes drastic variation during fasting. In D. labrax, observed variations concern, the relative content of the five lipoproteins and their composition, both in lipid and apolipoprotein content. These data indicate the presence of a cascade mechanism of maturation involving very-low-density lipoprotein, (VLDL), low-density lipoprotein (LDL)-1 and LDL-2. In addition, a metabolic correlation involves VLDL and high-density lipoprotein (HDL). VLDL are functionally comparable with mammalian chylomicrons; in fact, they disappear rapidly after feeding from the chromatographic patt…

Liraglutide Reduces Postprandial Hyperlipidemia by Increasing ApoB48 (Apolipoprotein B48) Catabolism and by Reducing ApoB48 Production in Patients Wi…

2018

Objective— Treatment with liraglutide, a GLP-1 (glucagon-like peptide-1) agonist, has been shown to reduce postprandial lipidemia, an important feature of diabetic dyslipidemia. However, the underlying mechanisms for this effect remain unknown. This prompted us to study the effect of liraglutide on the metabolism of ApoB48 (apolipoprotein B48). Approach and Results— We performed an in vivo kinetic study with stable isotopes (D 8 -valine) in the fed state in 10 patients with type 2 diabetes mellitus before treatment and 6 months after the initiation of treatment with liraglutide (1.2 mg/d). We also evaluated, in mice, the effect of a 1-week liraglutide treatment on postload triglycerides an…

Molecular diagnosis of hypobetalipoproteinemia: an ENID review.

2007

Abstract Primary hypobetalipoproteinemia (HBL) includes a group of genetic disorders: abetalipoproteinemia (ABL) and chylomicron retention disease (CRD), with a recessive transmission, and familial hypobetalipoproteinemia (FHBL) with a co-dominant transmission. ABL and CRD are rare disorders due to mutations in the MTP and SARA2 genes, respectively. Heterozygous FHBL is much more frequent. FHBL subjects often have fatty liver and, less frequently, intestinal fat malabsorption. FHBL may be linked or not to the APOB gene. Most mutations in APOB gene cause the formation of truncated forms of apoB which may or may be not secreted into the plasma. Truncated apoBs with a size below that of apoB-3…

Spectrum of mutations of the LPL gene identified in Italy in patients with severe hypertriglyceridemia.

2015

Background: Monogenic hypertriglyceridemia (HTG) may result from mutations in some genes which impair the intravascular lipolysis of triglyceride (TG)-rich lipoproteins mediated by the enzyme Lipoprotein lipase (LPL). Mutations in the LPL gene are the most frequent cause of monogenic HTG (familial chylomicronemia) with recessive transmission. Methods: The LPL gene was resequenced in 149 patients with severe HTG (TG>10mmol/L) and 106 patients with moderate HTG (TG>4.5 and <10mmol/L) referred to tertiary Lipid Clinics in Italy. Results: In the group of severe HTG, 26 patients (17.4%) were homozygotes, 9 patients (6%) were compound heterozygotes and 15 patients (10%) were simple heter…

Lipoprotein lipase-facilitated uptake of LDL is mediated by the LDL receptor

2007

LPL mediates the uptake of lipoproteins into different cell types independent of its catalytic activity. The mechanism of this process and its physiological relevance are not clear. Taking into account the importance of the endothelial barrier for lipoprotein uptake, in vitro studies with primary aortic endothelial cells from wild-type and low density lipoprotein receptor (LDLR)-deficient (LDLR(-/-)) mice were performed. Addition of LPL almost doubled the uptake of LDL into wild-type cells. However, there was virtually no LPL-mediated change of LDL uptake into LDLR(-/-) cells. Upregulation of LDLR by lipoprotein-deficient serum/lovastatin in wild-type cells resulted in a 7-fold increase of …