Influence du polymorphisme A4070G du facteur V (haplotype HR2) sur la résistance à la protéine C activée dans une population ayant présenté une thrombose veineuse

La maladie thromboembolique veineuse est une maladie commune et multifactorielle résultant de l'interaction entre des anomalies biologiques constitutionnelles et/ou acquises et des circonstances cliniques favorisantes. La résistance à la protéine C activée (RPCA) est l'anomalie biologique à l'origine de la plupart des thromboses veineuses. Chez une large majorité de patients, cette RPCA est due à une mutation unique du gène du facteur V appelé facteur V Leiden (FVL). Cependant 10% de la population caucasienne présentant une RPCA n'a pas la mutation FVL. L'haplotype HR2 a été décrit comme étant associé à une RPCA. Mais ceci est assez controversé. L'objectif de ce travail est de déterminer qu'elle est l'origine des RPCA associées à une maladie thromboembolique veineuse et non causée par le FVL. Nous avons cherché en particulier à connaître l'influence de l'haplotype HR2 sur ce phénomène. Notre étude porte sur 246 patients ayant présenté au moins un épisode thromboembolique. La RPCA a été déterminée par trois tests de mesure différents. Aucune association entre l'haplotype HR2 et la RPCA n'a été retrouvée dans ce travail. Par contre la RPCA déterminée avec le test original est corrélée avec le taux plasmatique de facteur VIII.TOULOUSE3-BU Santé-Centrale (315552105) / SudocTOULOUSE3-BU Santé-Allées (315552109) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Is it time to reconcile HDL with cardiovascular diseases and beyond? An update on a paradigm shift

International audienceNo abstract availabl

Caveolin-1 sensitizes vascular smooth muscle cells to mildly oxidized LDL-induced apoptosis

Oxidized low-density lipoprotein (oxLDL)-induced apoptosis of vascular cells may participate to plaque instability and rupture. Caveolin-1 has emerged as an important regulator of several signal transduction pathways and processes that play a role in atherosclerosis. In this study we examined the potential role of caveolin-1 in the regulation of oxLDL-induced Ca(2+) signaling and apoptosis in vascular smooth muscle cells (VSMC). Cells expressing caveolin-1 were more susceptible to oxLDL-induced apoptosis, and this was correlated with enhanced Ca(2+) entry and pro-apoptotic events. Moreover, caveolin-1 silencing by small interfering RNA decreased the level of apoptotic cells after oxLDL treatment. These findings provide new insights about the potential role of caveolin-1 in the regulation of oxLDL-induced apoptosis in vascular cells and its contribution to the instability of the plaque

Serum level of HDL particles are independently associated with long-term prognosis in patients with coronary artery disease: The GENES study

International audienceHDL-Cholesterol (HDL-C) is not an accurate surrogate marker to measure the cardioprotective functions of HDL in coronary artery diseases (CAD) patients. Hence, measurement of other HDL-related parameters may have prognostic superiority over HDL-C. In this work, we examined the predictive value of HDL particles profile for long-term mortality in CAD patients and to compare its informative value to that of HDL-C and apoA-I. HDL particles profiles were measured by nuclear magnetic resonance (NMR) spectroscopy in 214 male participants with stable CAD (45-74 years). Median follow up was 12.5 years with a 36.4% mortality rate. Cardiovascular mortality accounted for 64.5%. Mean concentrations of total HDL particles (HDL-P), small-sized HDL (SHDL-P) and apoA-I were lower in deceased than in surviving patients whereas no difference was observed according to HDL-C and large HDL particles. All NMR-HDL measures were correlated between themselves and with other HDL markers (HDL-C, apoA-I and LpA-I). In a multivariate model adjusted for cardiovascular risk factors and bioclinical variables, HDL-P and SHDL-P displayed the strongest inverse association with all-cause and cardiovascular mortality. Weaker associations were recorded for apoA-I. Based on our results, we conclude that HDL particle profile measured by NMR spectroscopy should be considered to better stratify risk in population at high risk or in the setting of pharmacotherapy

A reference measurement of circulating ATPase inhibitory factor 1 (IF1) in humans by LC-MS/MS: Comparison with conventional ELISA

International audienceATPase inhibitory factor 1 (IF1) is a 9.5 kDa protein that binds to mitochondrial and plasma membrane ATP synthase and selectively inhibits ATP hydrolysis. Recently, IF1 was identified in systemic circulation in humans. IF1 appeared as an independent determinant of HDL-cholesterol with lower levels in coronary heart disease (CHD) patients. Moreover, IF1 was also found to negatively associate with mortality in these patients, supporting the notion that circulating IF1 could be a promising biomarker of cardiovascular disease. However, in previous studies, IF1 was quantified by a non-standardized competitive enzyme-linked immunosorbent assay (ELISA). Herein, we have validated a liquid chromatography-tandem mass spectrometry method (LC-MS/MS) enabling the accurate quantification of IF1 in human plasma. Plasma IF1 was trypsin-digested through an optimized procedure before LC-MS/MS analysis. The method was successfully validated over 4 independent experiments into the range of 100-1500 ng/mL. Intraand inter-assay variation coefficients had never exceeded 14.2% and accuracy ranged between 95% and 102% for the selected EAGGAFGK peptide marker. Subsequently, the results of the LC-MS/MS method were compared with those obtained using ELISA in 204 individuals from the GENES study. We found that IF1 plasma levels obtained using both techniques were strongly correlated (r = 0.89, p < 0.0001), while the Bland-Altman plot did not indicate any major statistically significant differences. To clinically validate LC-MS/MS, we confirmed the positive correlation between IF1 plasma levels and HDL-cholesterol (r = 0.38, p < 0.0001). Besides, we found lower IF1 plasma levels in CHD patients compared to controls (431 +/- 132 ng/mL and 555 +/- 173 ng/mL, respectively; p < 0.0001). Hence, it can be concluded that the presented LC-MS/MS analytical method provides a highly specific strategy for IF1 quantification in human plasma and could be proposed as a reference method

Impact of micronutrient deficiency & malnutrition in systemic sclerosis: Cohort study and literature review

International audienceObjectives: The purpose of our study was to determine the prevalence and risk factors associated with malnutrition, and selenium (Se) and vitamin C (vitC) deficiencies in systemic sclerosis (SSc) patients.Methods: We included adult SSc patients fulfilling the 2013 ACR/EULAR criteria from the Toulouse University Hospital cohort who underwent a micronutrient workup (including vitC, Se or thiamine levels) between 2011 and 2016.Results: 82 patients were included, mostly women (76%), with a median age of 60 years. SSc was limited in 76% of the cases, with Scl-70 and centromere antibodies in 32% and 44%, respectively. Median disease duration was 7.4 years. Cardiac involvement was noticed in 19% and gastrointestinal tract in and 95%; 9% had pulmonary artery hypertension (PAH) and 63% had interstitial lung disease. Overt malnutrition was present in 14 (17%) patients. Micronutrient deficiencies included Se (35%), vitC (31%) and/or thiamine (6%). Malnourished patients had significantly a higher summed Medsger disease severity scales (7.5 vs. 5, P = .003), lower hemoglobin (10.6 vs. 12.9 g/dL, P < .0001) and vitC levels (3.6 vs. 10.6 mg/L, P = .003). Cardiac involvement was significantly associated with Se deficiency (OR 6.2, IC 95%[1.48-32.70], P = .05). The factors associated with vitC deficiency were malnutrition (OR 8.57, IC 95%[2.16-43.39], P = .003), modified Rodnan skin score ≤ 14 (OR 0.33, IC95[0.11-1], P = .05), PAH (27% in deficient vs. none in non-deficient patients, P = .0006) and esophagitis or Barrett's mucosa (OR 4.05, IC95[1.27-13.54], P = .02).Conclusions: Se testing should be considered as soon as cardiac involvement is suspected. VitC testing should be considered in malnourished SSc patients, especially if skin involvement is extensive

TRPC1 is regulated by caveolin-1 and is involved in oxidized LDL-induced apoptosis of vascular smooth muscle cells

Oxidized low-density lipoprotein (oxLDL) induced-apoptosis of vascular cells may participate in plaque instability and rupture. We have previously shown that vascular smooth muscle cells (VSMC) stably expressing caveolin-1 were more susceptible to oxLDL-induced apoptosis than VSMC expressing lower level of caveolin-1, and this was correlated with enhanced Ca(2+) entry and pro-apoptotic events. In this study we aimed to identify the molecular events involved in oxLDL-induced Ca(2+) influx and their regulation by the structural protein caveolin-1. In VSMC, transient receptor potential canonical-1 (TRPC1) silencing by ARN interference, prevents the Ca(2+) influx and reduces the toxicity induced by oxLDL. Moreover, caveolin-1 silencing induces concomitant decrease of TRPC1 expression and reduces oxLDL-induced-apoptosis of VSMC. OxLDL enhanced the cell surface expression of TRPC1, as shown by biotinylation of cell surface proteins, and induced TRPC1 translocation into caveolar compartment, as assessed by subcellular fractionation. OxLDL-induced TRPC1 translocation was dependent on actin cytoskeleton and associated with a dramatic rise of 7-ketocholesterol (a major oxysterol in oxLDL) into caveolar membranes, whereas the caveolar content of cholesterol was unchanged. Altogether, the reported results show that TRPC1 channels play a role in Ca(2+) influx and Ca(2+) homeostasis deregulation that mediate apoptosis induced by oxLDL. These data also shed new light on the role of caveolin-1 and caveolar compartment as important regulators of TRPC1 trafficking to the plasma membrane and apoptotic processes that play a major role in atherosclerosis

Treatment with PCSK9 inhibitors induces a more anti-atherogenic HDL lipid profile in patients at high cardiovascular risk

International audienceBackground: Proprotein Convertase Subtilisin/Kexin type 9 inhibitors (PCSK9-I) have been reported to cause a moderate increase in high-density lipoprotein (HDL) cholesterol in human studies. We thus evaluated the effect of two approved PCSK9-I on the concentration and lipid composition of HDL particle subclasses.Subjects and methods: 95 patients (62.8 ± 10.3 years old, 58% men), with or without statin and/or ezetimibe treatment and eligible for PCSK9-I therapy, received either evolocumab (140 mg) or alirocumab (75 or 150 mg). Their HDL particle profiles were measured by NMR spectroscopy at baseline and after 4 weeks of PCSK9-I treatment.Results: PCSK9-I treatment increased the level of HDL-C by 7%. The level of medium-sized HDL particles (M-HDL-P) increased (+8%) while the level of XL-HDL-P decreased (-19%). The lipid core composition was altered in the smaller S- and M-HDL-P, with a reduction in triglycerides (TG) and an enrichment in cholesterol esters (CE), whereas the for the larger XL- and L-HDL-P the relative CE content decreased and the TG content increased. Ezetimibe therapy differentially impacted the HDL particle distribution, independently of statin use, with an increase in S-HDL-P in patients not receiving ezetimibe.Conclusions: As S- and M-HDL-P levels are inversely related to cardiovascular risk, PCSK9-I treatment may result in a more atheroprotective HDL particle profile, particularly in patients not concomitantly treated with ezetimibe