A genomewide association study of smoking relapse in four European population-based samples.

OBJECTIVES: Genomewide association studies (GWAS) have identified clear evidence of genetic markers for nicotine dependence. Other smoking phenotypes have been tested, but the results are less consistent. The tendency to relapse versus the ability to maintain long-term abstinence has received little attention in genetic studies; thus, our aim was to provide a better biological understanding of this phenotype through the identification of genetic loci associated with smoking relapse. METHODS: We carried out a GWAS on data from two European population-based collections, including a total of 835 cases (relapsers) and 990 controls (abstainers). Top-ranked findings from the discovery phase were tested for replication in two additional independent European population-based cohorts. RESULTS: Of the seven top markers from the discovery phase, none were consistently associated with smoking relapse across all samples and none reached genomewide significance. A single-nucleotide polymorphism rs1008509, within the Xylosyltransferase II (XYLT2) gene, was suggestively associated with smoking relapse in the discovery phase (β=-0.504; P=5.6E-06) and in the first replication sample (ALSPAC) (β=-0.27; P=0.004; n=1932), but not in the second sample (KORA) (β=0.19; P=0.138; n=912). We failed to identify an association between loci implicated previously in other smoking phenotypes and smoking relapse. CONCLUSION: Although no genomewide significant findings emerged from this study, we found that loci implicated in other smoking phenotypes were not associated with smoking relapse, which suggests that the neurobiology of smoking relapse and long-term abstinence may be distinct from biological mechanisms implicated in the development of nicotine dependence.

High prevalence of anti-apolipoprotein/A-1 autoantibodies in maintenance hemodialysis and association with dialysis vintage.

Autoantibodies to apolipoprotein/A-1 (anti-ApoA-1 IgG) have pro-atherogenic properties in patients at high cardiovascular risk, but its prevalence in patients with end-stage kidney disease is unknown. The aims of this single-center, cross-sectional study were to assess the prevalence of anti-ApoA-1 antibodies in patients on maintenance hemodialysis (MHD), and to examine its correlation with inflammatory biomarkers related to atherosclerotic plaque vulnerability and dialysis vintage. To this purpose, anti-ApoA-1 IgG levels and the concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), metalloproteinase-9 (MMP-9), tumor necrosis factor-α, and C-reactive protein (CRP) were assessed in the sera of 66 MHD patients (mean age: 68 ± 14 years, 36% women, 32% diabetics). Anti-ApoA-1 IgG positivity (defined as a blood value ≥ 97.5(th) percentile of the normal distribution as assessed in healthy blood donors) was 20%. Circulating levels of anti-ApoA-1 IgG correlated positively with dialysis vintage, but not with cardiovascular risk factors or previous cardiovascular events; no significant correlations were found between the anti-ApoA1 IgG levels and circulating levels of IL-6, IL-8, MCP-1, MMP-9, CRP, or low-density lipoprotein-cholesterol. In multivariable linear regression, adjusted for age and sex, only dialysis vintage remained positively and independently associated with anti-ApoA-1 titers (β = 0.05, 95% CI: 0.006; 0.28, P = 0.049). In conclusion, the prevalence of anti-ApoA-1 IgG is raised in the MHD-population, and positively associated with dialysis vintage, a major determinant of cardiovascular outcome. Whether antiApoA-1 antibodies play a role in the pathophysiology of accelerated atherosclerosis in the MHD-population merits further study.

Association between obesity indices and cardiovascular risk factors in late adolescence in the Seychelles.

ABSTRACT: BACKGROUND: The ability of different obesity indices to predict cardiovascular risk is still debated in youth and few data are available in sub Saharan Africa. We compared the associations between several indices of obesity and cardiovascular risk factors (CVRFs) in late adolescence in the Seychelles. METHODS: We measured body mass index (BMI), waist circumference, waist/hip ratio (WHiR), waist/height ratio (WHtR) and percent fat mass (by bioimpedance) and 6 CVRFs (blood pressure, LDL-cholesterol, HDL-cholesterol, triglycerides, fasting blood glucose and uric acid) in 423 youths aged 19-20 years from the general population. RESULTS: The prevalence of overweight/obesity and several CVRFs was high, with substantial sex differences. Except for glucose in males and LDL-cholesterol in females, all obesity indices were associated with CVRFs. BMI consistently predicted CVRFs at least as well as the other indices. Linear regression on BMI had standardized regression coefficients of 0.25-0.36 for most CVRFs (p<0.01) and ROC analysis had an AUC between 60%-75% for most CVRFs. BMI also predicted well various combinations of CVRFs: 36% of male and 16% of female lean subjects (BMI P90). CONCLUSION: There was an elevated prevalence of obesity and of several CVRFs in youths in Seychelles. BMI predicted single or combined CVRFs at least as well as other simple obesity indices.

31/11/19 [i.e. 1er décembre], rue Olivier de Serres, [Football] Association, équipe Légion St Michel : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 57084

31/11/19 [i. e. 1er décembre], rue Olivier de Serres, [Football] Association, équipe Légion St Michel : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 57085

Assessment of particulate exposure and surface characteristics in association with urinary levels of 8-hydroxy-2'-deoxyguanosine, considered as marker of oxidative stress

Epidemiological studies have demonstrated that exposure to fine particles is associated to adverse health effects, including cancer, respiratory and cardiovascular diseases. However, mechanisms by which particles induce health effects remain unclear. According to one of the most investigated hypotheses, particles cause adverse effects through the production of reactive oxygen species (ROS), which are very hazardous compounds able to attack directly biological structures, including the DNA strand or the lipid bilayer of the cells. If the defense mechanisms, constituted of antioxidants, are not able to counter ROS, then these compounds will cause in the body a range of oxidation reactions called "oxidative stress". The aim of the present research project was to better understand mechanisms by which exposure to fine particles induces oxidative stress. The first point of this project was to check whether exposure to high levels of fine particles is directly linked to oxidative stress, and whether this oxidative stress is accompanied by the activation of the defense mechanisms (antioxidants). The second point was to study the role played by the particle surface characteristics in the oxidative stress process. For that purpose, a study was conducted in bus depots with the participation of 40 mechanics. First, occupational exposure to particles (PM4) and to other pollutants (NOx, O3) was measured over a two-day period. Then, urine samples of mechanics were collected in order to measure levels of 8-hydroxy-2'-deoxyguanosine (8OHdG) and antioxidants. 8OHdG is a molecule formed by the oxidation of DNA and allowing to assess the oxidative stress status of the mechanics. Finally, particles were collected on filters, and functional groups located on the particle surface were analyzed in the laboratory using a Knudsen flow reactor. This technique allows not only to quantify functional groups on the particle surface, but also to measure the reaction kinetics. Results obtained during the field campaign in bus depots showed that mechanics were exposed to rather low levels of PM4 (20-85 μg/m3) and of pollutants (NOx: 100-1000 ppb; O3: <15 ppb). However, despite this low exposure, urinary levels of the oxidative stress biomarker (8OHdG) increased significantly for non-smoking workers over a two-day period of shift. This oxidative stress was accompanied by an increase of antioxidants, indicating the activation of defense mechanisms. On the other hand, the analysis of functional groups on the particle surface showed important differences, depending on the workplace, the date and the activities of workers. The particle surface contained simultaneously antagonistic functional groups which did not undergo internal reactions (such as acids and bases), and was usually characterized by a high density of carbonyl functions and a low density of acidic sites. Reaction kinetics measured using the Knudsen flow reactor pointed out fast reactions of oxidizable groups and slow reactions of acidic sites. Several exposure parameters were significantly correlated with the increase of the oxidative stress status: the presence of acidic sites, carbonyl functions and oxidizable groups on the particle surface; reaction kinetics of functional groups on the particle surface; particulate iron and copper concentrations; and NOx concentration.

Périartérite noueuse et hépatite C: association fortuite [Periarteritis nodosa and hepatitis C: a fortuitous association?]

Polyarteritis nodosa is a vasculitis of unknown origin which can be rarely associated with hepatitis B. A exceptional clinical situation of a polyarteritis nodosa associated with hepatitis C is described. This case is also the occasion to review the clinical manifestations, the diagnostic strategy und the therapeutic options of this rare vasculitis.

The association of aldosterone with obesity-related hypertension and the metabolic syndrome.

Overweight and obesity are associated with arterial hypertension. Given the large increase in the obesity prevalence worldwide, the number of obese patients with hypertension is likely to increase substantially in the near future. Overweight and obese patients are exposed to an important metabolic and cardiovascular risk. The understanding of the mechanisms linking obesity to hypertension is important for specific prevention and therapy in this population. There is some evidence that obesity is associated with an increased aldosterone level. To date, 2 mechanisms may explain the interaction of fat tissue with the renin-angiotensin-aldosterone system, and therefore explain, in part, obesity-related hypertension. First, human adipose tissue produces several components of the renin-angiotensin-aldosterone system, mainly adipose tissue-derived angiotensinogen. Second, increased fatty acid production in the obese patient, especially nonesterified fatty acids, might stimulate aldosterone production, independent of renin. A better understanding of these mechanisms might have implications for the management of hypertension in overweight and obese patients. Because aldosterone also is associated with blood glucose and blood lipids, selective aldosterone blockade may represent a particularly attractive therapeutic strategy in obese patients with a clustering of cardiovascular risk factors.

Association Study of Common Genetic Variants and HIV-1 Acquisition in 6,300 Infected Cases and 7,200 Controls.

Multiple genome-wide association studies (GWAS) have been performed in HIV-1 infected individuals, identifying common genetic influences on viral control and disease course. Similarly, common genetic correlates of acquisition of HIV-1 after exposure have been interrogated using GWAS, although in generally small samples. Under the auspices of the International Collaboration for the Genomics of HIV, we have combined the genome-wide single nucleotide polymorphism (SNP) data collected by 25 cohorts, studies, or institutions on HIV-1 infected individuals and compared them to carefully matched population-level data sets (a list of all collaborators appears in Note S1 in Text S1). After imputation using the 1,000 Genomes Project reference panel, we tested approximately 8 million common DNA variants (SNPs and indels) for association with HIV-1 acquisition in 6,334 infected patients and 7,247 population samples of European ancestry. Initial association testing identified the SNP rs4418214, the C allele of which is known to tag the HLA-B*57:01 and B*27:05 alleles, as genome-wide significant (p = 3.6×10(-11)). However, restricting analysis to individuals with a known date of seroconversion suggested that this association was due to the frailty bias in studies of lethal diseases. Further analyses including testing recessive genetic models, testing for bulk effects of non-genome-wide significant variants, stratifying by sexual or parenteral transmission risk and testing previously reported associations showed no evidence for genetic influence on HIV-1 acquisition (with the exception of CCR5Δ32 homozygosity). Thus, these data suggest that genetic influences on HIV acquisition are either rare or have smaller effects than can be detected by this sample size.

Genetic relationships between suicide attempts, suicidal ideation and major psychiatric disorders: A genome-wide association and polygenic scoring study.

Epidemiological studies have recognized a genetic diathesis for suicidal behavior, which is independent of other psychiatric disorders. Genome-wide association studies (GWAS) on suicide attempt (SA) and ideation have failed to identify specific genetic variants. Here, we conduct further GWAS and for the first time, use polygenic score analysis in cohorts of patients with mood disorders, to test for common genetic variants for mood disorders and suicide phenotypes. Genome-wide studies for SA were conducted in the RADIANT and GSK-Munich recurrent depression samples and London Bipolar Affective Disorder Case-Control Study (BACCs) then meta-analysis was performed. A GWAS on suicidal ideation during antidepressant treatment had previously been conducted in the Genome Based Therapeutic Drugs for Depression (GENDEP) study. We derived polygenic scores from each sample and tested their ability to predict SA in the mood disorder cohorts or ideation status in the GENDEP study. Polygenic scores for major depressive disorder, bipolar disorder and schizophrenia from the Psychiatric Genomics Consortium were used to investigate pleiotropy between psychiatric disorders and suicide phenotypes. No significant evidence for association was detected at any SNP in GWAS or meta-analysis. Polygenic scores for major depressive disorder significantly predicted suicidal ideation in the GENDEP pharmacogenetics study and also predicted SA in a combined validation dataset. Polygenic scores for SA showed no predictive ability for suicidal ideation. Polygenic score analysis suggests pleiotropy between psychiatric disorders and suicidal ideation whereas the tendency to act on such thoughts may have a partially independent genetic diathesis. © 2014 Wiley Periodicals, Inc.