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Biomedical subjects

J C Fruchart

Publications and source records attributed to J C Fruchart.

At least 325 records · Page 18Linked to original sources
PubMed1991

Lowering of HDL2-cholesterol and lipoprotein A-I particle levels by increasing the ratio of polyunsaturated to saturated fatty acids.

The protective role of high-density lipoproteins (HDLs) has been attributed to the subfractions HDL2 (according to the density) and lipoprotein A-I (LpA-I) (according to the composition in apolipoproteins). We investigated the effect of a high ratio of polyunsaturated to saturated fatty acids (P:S) on these subfractions in a homogeneous group of young adult males. Two prescribed diets were consumed successively at the subjects' homes for 3 wk each in a random order; one diet contained 70 g butter (P:S 0.2, diet B), the other contained 70 g sunflower margarine (P:S 1.1, diet M). Total calorie, fat, and cholesterol intakes were similar for the two diets. Cholesterol and apolipoprotein B in serum and in low-density lipoproteins (LDLs) were lower with diet M than with diet B. However, significant decreases in protective subfractions of HDL, HDL2, and LpA-I were observed. This undesirable effect of the diet with a high P:S could cancel the benefits of lowering the LDL-cholesterol concentrations.

Adult↗
PubMed1991

n-3 polyunsaturated fatty acids raise low-density lipoproteins, high-density lipoprotein 2, and plasminogen-activator inhibitor in healthy young men.

The effects of a moderate supplementation in n-3 polyunsaturated fatty acids (PUFAs) were investigated in 36 young healthy adult males. Factors investigated were lipoprotein (including HDL subfractions and apolipoproteins) and hemostasis indexes, assessed by platelet aggregation and plasminogen-activator-inhibitor (PAI) activity. Fat-controlled diets were prescribed, one with and one without a fish-oil supplement (control diet), successively during 3 wk in random order. Total calorie, fat, and cholesterol intakes were similar in the two diets. Triglycerides in serum and very-low-density lipoproteins were lower and high-density-lipoprotein 2 cholesterol was higher with the n-3 PUFA-supplemented diet. These effects as well as a significant decrease in platelet aggregation can be considered beneficial in terms of cardiovascular risk. However, significant increases in low-density-lipoprotein cholesterol and PAI activity occurred and were correlated. This latter effect could be detrimental.

Adult↗
PubMed1991

Plasma concentrations of apolipoprotein A-I containing particles in normolipidaemic young men.

Low levels of plasma high-density lipoprotein (HDL)-cholesterol and apolipoprotein (apo)-A-I are associated with premature coronary heart disease. However, particles in the density range of HDL are heterogeneous. Two main types of apo A-I-containing particles can be identified, one species containing both apo A-I and apo A-II (Lp A-I:A-II) and the other apo A-I but no apo-A-II (Lp A-I). This study was designed to measure HDL cholesterol, apo A-I, and, using a new procedure, Lp A-I in 233 healthy normolipidaemic young men (cholesterol less than 250 mg dl-1 and triglycerides less than 200 mg dl-1). Among these subjects, the composition of HDL was very variable as indicated by the 10th and the 90th percentiles of the HDL-cholesterol/apo A-I ratios which were 0.32 and 0.49, respectively. The 10th and 90th percentiles of apo A-I and Lp A-I:A-II were 126 and 167 mg dl-1 and 83 and 116 mg dl-1, respectively. On the other hand, Lp A-I showed a much larger variation, the 10th and 90th percentiles being at 33 and 62 mg dl-1, respectively. The distribution of individual values of Lp A-I showed that this fraction of apo A-I-containing particles was very variable among subjects, the Lp A-I/apo A-I ratio extending from 0.18 to 0.58. Triglycerides, Lp A-I and Lp A-I:A-II were correlated with HDL cholesterol, but no correlation between apo A-I containing subfractions and plasma triglycerides was noticed. Since preliminary results from angiographic and clinical studies show that Lp A-I could exert a protective role for atherosclerosis, it would seem that the measurement of Lp A-I might help in the future to characterize better the individual's risk for atherosclerosis.

Adolescent↗
PubMed1991

Apolipoprotein B polymorphism and altered apolipoprotein B concentrations in Congolese blacks.

The immunoreactivity of apolipoprotein B (apo B) in plasma obtained from 238 unrelated black African male subjects from the People's Republic of Congo was analysed by non-competitive Enzyme Linked-Immunosorbent Assay (ELISA) with monoclonal BIP 45 anti-LDL antibody. The polymorphism detected by BIP 45 monoclonal antibody is identical to the Ag(c,g) polymorphism. Antibody BIP 45 distinguishes three apo B allotypes (immunophenotypes) encoded by the two allelic genes apo B Ag(c) and apo B Ag(g). Because of co-dominant transmission, genotypes may be inferred from allotypes, and it has been shown that BIP 45 binds strongly to the Ag(c) factor and only weakly to the allelic Ag(g) factor. Analysis of the Congolese plasma samples indicated that 67.65% of them bound BIP 45 with low affinity (Ag(c-,g+) genotype), 28.15% with intermediate affinity (Ag(c+,g+) genotype) and 4.20% with high affinity (Ag(c+,g-) genotype). According to the Hardy-Weinberg equilibrium, this corresponds to gene frequencies of 0.817 and 0.183 for the type Ag(g)/Ag(c) alleles, respectively. After adjustment for age and body-mass index, it was found that the Ag(c) allele decreases the apo B level by 9.62 mg/dl and that the Ag(g) allele increases apo B by 0.43 mg/dl. Therefore, as much as 4.30% of the genetic variance for apo B level could be accounted for by the Ag(c,g) gene locus.

Alleles↗
PubMed1991

Apolipoprotein A-I-containing lipoproteins in human umbilical cord blood. Relation to proapolipoprotein A-I and lecithin:cholesterol acyltransferase.

Lipids, apolipoproteins, lipoproteins, as well as lipoproteins containing both apo A-I and apo A-II (Lp A-I:A-II) or apo A-I but no apo A-II (Lp A-I), proapolipoprotein (proapo) A-I and the activity of lecithin:cholesterol acyltransferase (LCAT), were investigated in umbilical cord sera of 67 term human neonates (30 females and 37 males). Lp A-I and Lp A-I:A-II were present in umbilical cord sera with levels of 0.26 +/- 0.1 and 0.33 +/- 0.15 g/l, respectively. Furthermore, the absolute amount of proapo A-I was lower in cord blood than in adult plasma, but in view of the lower apo A-I levels in umbilical cord sera it comprised 10.48 +/- 3.86% of total apo A-I and was thus significantly higher than in adult plasma (7.1 +/- 0.9%). Proapo A-I was highly correlated with HDL cholesterol and apo A-I. Total serum LCAT activity was about 50% of adult plasma and was highly correlated with Lp A-I, but not with Lp A-I:A-II. We conclude that human umbilical cord serum contains both Lp A-I and Lp A-I:A-II particles and that the LCAT activity is predominantly related with the Lp A-I subfraction. The higher percentage in umbilical cord sera of proapo A-I may indicate a higher turnover of apo A-I or a lower activity of the proapo A-I cleaving enzyme which is still not identified.

Apolipoprotein A-I↗
PubMed1991

Relation of arteriographically defined coronary artery disease to serum lipoprotein particles mapped with monoclonal antibodies.

BACKGROUND: This study was designed to investigate the relation of a molecular analysis of apolipoprotein B (apoB)-containing atherogenic lipoprotein particles to coronary artery disease (CAD) in middle-aged men. METHODS AND RESULTS: Two groups of men were studied. The first consisted of 97 patients with angiographically documented CAD (greater than 50% stenosis of at least one coronary artery). The second group consisted of 145 subjects without symptomatic CAD, who served as controls. In both groups, measurements were obtained for total cholesterol level, triglyceride level, cholesterol contents in apoB- and nonapoB-containing particles (LpB, LpnonB), total apoB and apolipoprotein AI (apoAI levels), lipoprotein particles recognized by monoclonal antibodies anti-apoB (LpBL3, LpBL5, LpBL7) and anti-apoAI (LpAI-2GII). Taking into account age, body mass index, hypertension, diabetes, smoking habits, and drug consumption, the analysis showed that the mean levels of cholesterol were identical in both groups but differed when cholesterol content in LpB and LpnonB subfractions were assessed, thus reflecting an increase in the low density fraction and a decrease in the high density fraction, respectively. This was confirmed by an increase in total apoB and a decrease in total apoAI. Measurements of LpBL3, LpBL5, LpBL7, and LpAI-2GII particles also discriminated between the two groups. After adjustment for cholesterol content in LpnonB particles, a difference in total apoB was no longer significant between groups, whereas LpBL3, LpBL5, and LpBL7 levels remained significantly higher in CAD patients. CONCLUSIONS: The measurement of separate concentrations of apoB in different particles may permit a more-accurate assessment of CAD risk than measurements of total apoB levels.

Adult↗
PubMed1991

A phenocopy of type III dysbetalipoproteinemia occurring in a candidate family for a putative apo E receptor defect.

On theoretical grounds, an apo E receptor defect should be manifested by the accumulation of lipoprotein remnants that are normally cleared by this receptor and cannot be processed by the normal apo B, E receptor (LDL-receptor). Furthermore, the defect should not be selective for a specific apo E phenotype since none of the isoforms would be cleared preferentially. Our search for such an occurrence led us to the discovery, in five members of a family of ten, of a unique dyslipoproteinemia mimicking type III. As in type III, plasma levels of cholesterol, triglycerides, VLDL-cholesterol, VLDL-triglycerides and apo E, as well as the VLDL-C/TG ratio, were high. LDL-cholesterol and HDL-cholesterol tended to be low. The clearance of plasma triglycerides after a fat load was impaired. Tubero-eruptive xanthomas, arcus corneae and manifestations of atherosclerosis were present in some individuals. In contrast to type III, the dyslipoproteinemia occurred in subjects bearing three different apo E phenotypes: E4/2, E4/3 and E3/2. VLDL-apo B levels were markedly increased, the VLDL-C/VLDL-B ratio was low and a double pre-beta band was present on lipoprotein electrophoresis. In spite of high apo E and borderline high apo CIII plasma levels, levels of the lipoprotein particles LpCIII:B and LpE:B, which characterize type III, were not raised. Rapid weight loss or treatment with a fibrate was observed to normalize the lipoprotein profile. It is surmised that the apo E-rich lipoprotein particles accumulating in this type III phenocopy with "hyperapoprebetalipoproteinemia" could be those that are normally cleared by an apo E receptor.

Adult↗
PubMed1991

In vivo metabolism of apolipoprotein A-I on high density lipoprotein particles LpA-I and LpA-I,A-II.

Apolipoprotein (apo) A-I is the major protein in high density lipoproteins (HDL) and is found in two major subclasses of lipoproteins, those containing apolipoprotein A-II (termed LpA-I,A-II) and those without apoA-II (termed LpA-I). The in vivo kinetics of apoA-I on LpA-I and LpA-I,A-II were investigated in normolipidemic human subjects. In the first series of studies, radiolabeled apoA-I and apoA-II were reassociated with autologous plasma lipoproteins and injected into normal subjects. LpA-I and LpA-I,A-II were isolated from plasma at selected time points by immunoaffinity chromatography. By 24 h after injection, only 52.8 +/- 1.0% of the apoA-I in LpA-I remained, whereas 66.9 +/- 2.7% of apoA-I in LpA-I,A-II remained (P less than 0.01). In the second series of studies, purified apoA-I was labeled with either 131I or 125I and reassociated with autologous plasma. Isolated LpA-I and LpA-I,A-II particles differentially labeled with 131I-labeled apoA-I and 125I-labeled apoA-I, respectively, were simultaneously injected into study subjects. The plasma residence time of apoA-I injected on LpA-I (mean 4.39 days) was substantially shorter than that of apoA-I injected on LpA-I,A-II (mean 5.17 days), with a mean difference in residence times of 0.79 +/- 0.08 days (P less than 0.001). These data demonstrate that apoA-I injected on LpA-I is catabolized more rapidly than apoA-I injected on LpA-I,A-II. The results are consistent with the concept that LpA-I and LpA-I,A-II have divergent metabolic pathways.

Adult↗
PubMed1991

[Interaction between LDL receptor and lipoproteins containing apo B].

The physiocochemically defined lipoproteins such as VLDL, LDL are comprised of subpopulations with different lipid and apolipoprotein composition. In order to determine the respective roles of different apolipoproteins (B, C-III, E) in their metabolism, four species (LpB, LpB:E, LpB: C-III and LpB: C-III: E) have been separated by sequential immunoaffinity chromatography. We examined the binding characteristics of each lipoprotein to HeLa cells and expressed the results in relation to the number of moles of apo B. LpB particles which contained apo B as their sole apolipoprotein had lower affinity for the LDL receptor that did total LDL but an apparently higher number of binding sites. The presence of apo E of phenotype E3 or E4 on one particle increased the affinity for the receptor. The apparent number of binding sites decreased probably due to the fact that a particle containing multiple copies of apo E bound to more than one molecule of receptor. Interaction with several LDL receptors would also explain the higher binding affinity which we observed. When the apo E phenotype was E2/E2, the LpB: E particle did not bind to the receptor. We showed also that apo C-III, when present, diminished the binding of apo B containing lipoproteins. These data suggest that apolipoproteins E and C-III impaired the interaction of apo B with the LDL receptor. It is likely that in LpB: E only apo E (in the case of E3 or E4 phenotype) participates in the LDL receptor binding.

Apolipoproteins B↗
PubMed1991

Diverse effect of ethnicity on plasma lipoprotein[a] levels in heterozygote patients with familial hypercholesterolemia.

Plasma lipids, lipoproteins, and lipoprotein[a] (Lp[a]) levels were determined in 216 members of 14 families with familial hypercholesterolemia (FH). Ninety-nine subjects harbored a mutant low density lipoprotein (LDL) receptor allele as confirmed by molecular genetic analysis. Four different mutant alleles were identified, each in a defined genetic group, Druze, Christian-Arabs, and Ashkenazi and Sephardic Jews. The findings in FH subjects (cases) were compared with their nonaffected family members (controls). Plasma Lp[a] levels increased with age in the controls but not in cases and were different among the four genetic groups. Mean plasma Lp[a] levels were significantly higher in cases (33 mg/dl) than in controls (22 mg/dl). Plasma LDL cholesterol levels were raised in cases of the four genetic groups to a similar extent, in contrast to the mean plasma Lp[a] that varied. The Lp[a] level was higher by 30-33% in cases from the Druze, Christian-Arabs, and Jewish-Ashkenazi groups but by 110% in the Jewish-Sephardic group. Apo[a] isoform distribution was similar in cases and controls within each genetic group. Lp[a] levels were highest in subjects with LpS1 isoform, in particular in cases from the Jewish-Sephardic group. These data indicate that the higher Lp[a] levels in FH heterozygotes cannot be attributed solely to lack of functional LDL receptor molecules but possibly reflect multiple gene interactions.

Adolescent↗
PubMed1991

[Lipids, lipoproteins and atherosclerosis].

Cardiovascular diseases are the number one cause of death in France: 36.4%. Abnormalities of the metabolism of lipoproteins constitute the major predisposing factor for the development and progression of arterial lesions. These abnormalities are very often genetically linked and their expression is influenced by environmental factors (nutrition, smoking ...). The prevention of cardiovascular diseases is of prime importance and the detection of atherosclerosis risk makes up one of the essential steps to this approach. Detection must be realised as early as possible, for in the cases of metabolic abnormalities, the pathogenicity of the process evolves slowly, without showing outward clinical signs and leads to major long-term damage: myocardial infarction in particular. Measuring total cholesterol and total triglycerides are insufficient, particularly when the values are not extreme, to evaluate atherosclerosis risk; these measurements must be complimented by these of the lipoproteins. Current research allows earlier and more precise biological tests of coronary risk to be envisaged.

Apolipoprotein A-I↗
PubMed1991

Pharmacomodulation of 7-(2-methylene-butyryl)-2,3-dihydrobenzoxazin-[1,4]-3-one structure and normolipemic activity.

A series of compounds from 7-(2-methylene butyryl)-2,3-dihydro benzoxazin-[1,4]-3-one was synthesized and evaluated for its lipid lowering action in animal models. Substitutions in positions 2, 4 and 7 were performed. The results of the structure-activity relationships are very difficult to be interpreted. The different modifications tested did not show any improvement in the normolipemic activity.

Animals↗
PubMed1991

[From cholesterol to lipoprotein particle markers and/or risk factors].

Among the risk factors for atherosclerosis, lipoproteins play a central role, particularly in the development of coronary artery disease. The plasma cholesterol level was the first definite indicator of the risk factor. Thereafter, technical progress has permitted the measurement of the cholesterol fractions, LDL cholesterol which is positively correlated with atherosclerosis, and HDL cholesterol, which is protective. However, the measurement of these fractions in a subject does not permit accurate determination of the risk to the subject. Likewise the measurement of apo A-I and B has brought an improvement in determining the risk factor but is still insufficient. The clarification of new markers would allow better definition of the potential atherogenic risk to a given individual Lp A-I (lipoproteins containing apo A-I but not apo A-II) level is probably an important indicator. Similarly, Lp(a) level is certainly an atherogenic lipoprotein and the apo E phenotype modulates the development of atherosclerosis. All these new markers and others, in the future, will better define the risk for an asymptomatic subject, with regard of atherosclerosis and therefore help to prevent it.

Arteriosclerosis↗
PubMed1991

Insulin-resistance and lipoprotein abnormalities.

Resistance to insulin-stimulated glucose uptake is associated with an increased rate of synthesis and secretion of VLDL-triglycerides and, in the absence of adequate removal capacity, with hypertriglyceridemia. Subjects with a low glucose disposal rate or a high degree of insulin resistance (as measured by the euglycemic hyperinsulin clamp technique) have also decreased HDL cholesterol levels. The recent developments in the chemistry of lipoproteins indicate that the physicochemically defined lipoproteins such as VLDL, IDL, LDL or HDL are both chemically and metabolically heterogeneous. According to the Alaupovic concept, the plasma lipoprotein system consists of a mixture of particles, each of which is characterized by a unique apolipoprotein composition. Using enzyme-linked differential antibody immunosorbent assay and differential electroimmunoassay, we have discovered that the determination of lipoprotein particle profiles is essential for further clarification of the diagnostic value of measuring apo B and apo A-I. The metabolism of apo B and apo A-I containing lipoprotein particles seems to be affected primarily by their corresponding apolipoprotein composition. Some particular subpopulations of apo B containing lipoprotein particles, such as LpB containing only apo B, LpB:E containing apo B and (a) have been identified as important risk factors in atherosclerosis. We have also recently demonstrated that the protective effect of HDL is due to particles containing apo A-I but not apo A-II (LpA-I), while have little or have no effect those containing apo A-I and apo A-II (LpA-I:A-II). Non-insulin-dependent diabetic patients (NIDDM) are characterized by increased concentrations of cholesteryl ester rich LpB and triglyceride rich LpB:C-III and LpB:E.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoproteins↗
PubMed1990

Cholesterol efflux from adipose cells is coupled to diacylglycerol production and protein kinase C activation.

Apolipoprotein A-I (apo A-I)*/DMPC complexes have been previously shown to promote cholesterol efflux from cholesterol-preloaded adipose cells whereas apo A-II/DMPC complexes, which bind to the same cell surface binding sites, were ineffective. Addition of apo A-I/DMPC complexes led to a rapid and transient formation of diacylglycerol. However, in contrast to PGF2 alpha (Doglio et al., Proc. Natl. Acad. Sci. USA, 1989, 86, 1148), no accumulation of inositol phosphates was observed. Apo A-II/DMPC complexes had no effect on diacylglycerol formation. Stimulation by apo A-I/DMPC complexes or native HDL3 of cells prelabelled with (2-palmitoyl 9,10[3H])phosphatidylcholine induced also the formation of labelled diacylglycerol whereas apo A-II/DMPC complexes and HDL3 treated with tetranitromethane showed no effect. Direct activation of protein kinase C(s) by PMA promoted cholesterol efflux providing that DMPC liposomes were present as cholesterol acceptor. It is proposed that lipoprotein particles have two separate effects, i.e. a ligand-induced effect leading to cholesterol translocation from intracellular stores to the cell surface and a bilayer-induced effect allowing cholesterol efflux from the cell surface to the acceptor.

Adipose Tissue↗
PubMed1990

Lipoprotein particles in homozygous familial hypercholesterolemic patients treated with portacaval shunt and LDL apheresis.

Lipoprotein particles containing apolipoproteins (Apo) were studied by enzyme-linked-immunosorbent assay in two homozygous familial hypercholesterolemic patients (1 male and 1 female) with portacaval shunts, and in controls. Total Apo B, total cholesterol and LDL cholesterol were increased in both patients while complex Apo B containing particles, Lp CIII: B, were not increased in these FH patients. The dextran-sulfate cellulose columns (Liposorber LA-40) had an excellent adsorption selectivity and adsorption capacity for lipoprotein particles containing Apo B and a minimum adsorption capacity in Apo AI and Apo AII-containing particles. This apheresis technique selectively depleted plasma of atherogenic Apo B-containing particles with a minimal loss of antiatherogenic Apo AI-containing particles.

Adolescent↗