Personne :
Guénard, Frédéric

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Université Laval. Institut sur la nutrition et les aliments fonctionnels
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Voici les éléments 1 - 9 sur 9
  • Publication
    Differential methylation in visceral adipose tissue of obese men discordant for metabolic disturbances
    (American Physiological Society, 2014-03-15) Guénard, Frédéric; Biron, Simon; Biertho, Laurent; Pérusse, Louis; Lescelleur, Odette; Vohl, Marie-Claude; Deshaies, Yves; Marceau, Simon; Tchernof, André
    Obesity is associated with an increased risk of Type 2 diabetes and cardiovascular diseases (CVD). The severely obese population is heterogeneous regarding CVD risk profile. Our objective was to identify metabolic pathways potentially associated with development of metabolic syndrome (MetS) through an analysis of overrepresented pathways from differentially methylated genes between severely obese men with (MetS+) and without (MetS-) the MetS. Genome-wide quantitative DNA methylation analysis in VAT of severely obese men was carried out using the Infinium HumanMethylation450 BeadChip. Differences in methylation levels between MetS+ (n = 7) and MetS- (n = 7) groups were tested. Overrepresented pathways from the list of differentially methylated genes were identified and visualized with the Ingenuity Pathway Analysis system. Differential methylation analysis between MetS+ and MetS- groups identified 8,578 methylation probes (3,258 annotated genes) with significant differences in methylation levels (false discovery rate-corrected DiffScore ≥ |13| ∼ P ≤ 0.05). Pathway analysis from differentially methylated genes identified 41 overrepresented (P ≤ 0.05) pathways. The most overrepresented pathways were related to structural components of the cell membrane, inflammation and immunity and cell cycle regulation. This study provides potential targets associated with adipose tissue dysfunction and development of the MetS.
  • Publication
    Accès libre
    Body mass index is associated with epigenetic age acceleration in the visceral adipose tissue of subjects with severe obesity
    (Springer, 2019-12-02) Guénard, Frédéric; Toro Martin, Juan de; Hould, Frédéric-Simon; Vohl, Marie-Claude; Lebel, Stéfane; Tchernof, André; Julien, François; Marceau, Simon
    Background There is solid evidence that obesity induces the acceleration of liver epigenetic aging. However, unlike easily accessible blood or subcutaneous adipose tissue, little is known about the impact of obesity on epigenetic aging of metabolically active visceral adipose tissue (VAT). Herein, we aimed to test whether obesity accelerates VAT epigenetic aging in subjects with severe obesity. Results A significant and positive correlation between chronological age and epigenetic age, estimated with a reduced version of the Horvath’s epigenetic clock, was found in both blood (r = 0.78, p = 9.4 × 10−12) and VAT (r = 0.80, p = 1.1 × 10−12). Epigenetic age acceleration, defined as the residual resulting from regressing epigenetic age on chronological age, was significantly correlated with body mass index (BMI) in VAT (r = 0.29, p = 0.037). Multivariate linear regression analysis showed that, after adjusting for chronological age, sex and metabolic syndrome status, BMI remained significantly associated with epigenetic age acceleration in VAT (beta = 0.15, p = 0.035), equivalent to 2.3 years for each 10 BMI units. Binomial logistic regression showed that BMI-adjusted epigenetic age acceleration in VAT was significantly associated with a higher loss of excess body weight following biliopancreatic diversion with duodenal switch surgery (odds ratio = 1.21; 95% CI = 1.04–1.48; p = 0.03). Conclusions Epigenetic age acceleration increases with BMI in VAT, but not in blood, as previously reported in liver. These results suggest that obesity is associated with epigenetic age acceleration of metabolically active tissues. Further studies that deepen the physiological relevance of VAT epigenetic aging will help to better understand the onset of metabolic syndrome and weight loss dynamics following bariatric surgery.
  • Publication
    Accès libre
    Common sequence variants in CD163 gene are associated with plasma triglyceride and total cholesterol levels in severely obese individuals
    (Longdom Publishing SL, 2014-11-27) Guénard, Frédéric; Marianne, Cormier; Biron, Simon; Deshaies, Yves; Biertho, Laurent; Pérusse, Louis; Lescelleur, Odette; Vohl, Marie-Claude; Marceau, Simon
    Objective: The CD163 glycoprotein is a member of the scavenger receptor cysteine-rich superfamily acting as an inflammatory modulator inducing anti-inflammatory pathways. Previous findings from our group identified this gene as being differentially expressed in visceral adipose tissue (VAT) of severely obese men with vs. without the metabolic syndrome. The current study aimed to test the association between CD163 gene polymorphisms and obesity-related metabolic complications. Methods: Sequencing of the CD163 gene region was conducted in 25 severely obese individuals. Eleven tagging SNPs (tSNP) were selected and tested for association with obesity-related complications in nearly 1900 severely obese individuals. To further explore potential mechanisms underlying associations identified, the impact of tSNPs on methylation levels of 3 CpG sites (two promoter and one intronic) and gene expression levels were tested in a subset of 14 individuals. Results: Rare allele carriers for rs7980201 demonstrated lower fasting total cholesterol (total-C) levels (p=0.01) while rs4883263 rare allele carriers had increased total-C (p=0.04) and triglyceride (TG) levels (p=0.01). An association identified between rs7980201 SNP and methylation level of a promoter CpG site (p=0.04) suggested an impact on CD163 gene methylation in VAT, but such association was not reflected at gene expression level. Conclusion: The current study reports association of CD136 gene variations with fasting total-C and TG levels and suggests that CD163 SNPs could contribute to the inter-individual variability observed in obesity-related metabolic complications.
  • Publication
    Accès libre
    The rare allele of DGKZ SNP rs10838599 is associated with variability in HDL-cholesterol levels among severely obese patients
    (Open Access Text Pvt. Ltd, 2016-05-12) Guénard, Frédéric; Pérusse, Louis; Hould, Frédéric-Simon; Deshaies, Yves; Marceau, Picard; Bégin, Stéphanie; Vohl, Marie-Claude; Lebel, Stéfane; Tchernof, André
    Introduction: Diacylglycerol kinase-zeta, one of the ten isoforms of DGKs expressed in mammals is an important enzyme of lipid metabolism. It catalyzes the interconversion of diacylglycerol and phosphatidic acid, two major second messengers. Its gene DGKZ has been previously identified as being overexpressed and undermethylated in visceral adipose tissue of patients with (MetS+) versus without (MetS-) the metabolic syndrome (MetS). Objective: The aim of this study was to investigate the associations between DGKZ gene polymorphisms (SNPs) and phenotypes related to MetS (BMI, waist girth, CRP, fasting glucose, lipid profile (triglycerides, total-cholesterol, LDL-cholesterol and HDL-cholesterol (HDL-C)), resting systolic and diastolic blood pressures). Methods: The study sample included 1752 severely obese participants who underwent bariatric surgery. Associations between the five selected tSNPs of DGKZ and features of the MetS were tested. The effects of these SNPs on DGKZ methylation and expression levels were tested in subgroups of 32 and 14 obese subjects, respectively. Correlations between methylation and expression levels were also computed. Results: Homozygotes for the rare allele of rs10838599 displayed higher plasma HDL-C concentrations compared to the other genotype groups (p=0.03). For gene methylation, only a trend with the cg05412031 CpG site (p=0.09) was found for the single significantly phenotype-associated SNP. There was no significant correlation between DGKZ methylation at cg05412031 and expression levels. Conclusion: These results suggest that DGKZ SNP rs10838599 modulates plasma HDL-C levels thereby its gene contributes to the inter-individual variability observed in the cardiometabolic risk profile of patients with severe obesity.
  • Publication
    Association of LIPA gene polymorphisms with obesity-related metabolic complications among severely obese patients
    (NAASO the Obesity Society, 2012-10-17) Guénard, Frédéric; Biron, Simon; Biertho, Laurent; Pérusse, Louis; Lescelleur, Odette; Houde, Alain; Vohl, Marie-Claude; Deshaies, Yves; Marceau, Simon; Bouchard, Luigi; Tchernof, André
    The lipase A, lysosomal acid, cholesterol esterase enzyme (LIPA) is involved in the hydrolysis of triglycerides (TGs) and cholesteryl esters (CEs) delivered to lysosomes. LIPA deficiency in human causes two distinct phenotypes characterized by intracellular storage of CE and derangements in the control of cholesterol production, namely the Wolman disease (WD) and the CE storage disease (CESD). To test the potential association of LIPA gene polymorphisms with obesity-related metabolic complications, promoter, exons, and intronic flanking regions of the LIPA gene were first sequenced in 25 individuals. From the 14 common polymorphisms identified, 12 tagging single-nucleotide polymorphisms (tSNPs) were genotyped in a cohort of 1,751 obese individuals. After adjustments for the effect of age, sex, diabetes, and medication, the C allele of SNP rs1051338 was associated with lower blood pressure (BP; systolic (SBP) P = 0.004; diastolic (DBP) P = 0.006). Three of the tested SNPs were associated with modifications of the plasma lipid profile. The G/G genotype of rs2071509 was associated with higher high-density lipoprotein cholesterol (HDL-C) levels (P = 0.009) and minor allele of rs1131706 was also associated with higher HDL-C (P = 0.004) and an association between rs3802656 and total cholesterol (total-C)/HDL-C ratio was identified (P = 0.04). These results thus suggest that LIPA polymorphisms contribute to the interindividual variability observed in obesity-related metabolic complications.
  • Publication
    Accès libre
    Genetic regulation of differentially methylated genes in visceral adipose tissue of severely obese men discordant for the metabolic syndrome
    (Elsevier, 2017-02-01) Guénard, Frédéric; Biron, Simon; Biertho, Laurent; Pérusse, Louis; Lescelleur, Odette; Vohl, Marie-Claude; Marceau, Simon (***WMS); Deshaies, Yves; Tchernof, André
    A genetic influence on methylation levels has been reported and methylation quantitative trait loci (meQTL) have been identified in various tissues. The contribution of genetic and epigenetic factors in the development of the metabolic syndrome (MetS) has also been noted. To pinpoint candidate genes for testing the association of SNPs with MetS and its components, we aimed to evaluate the contribution of genetic variations to differentially methylated CpG sites in severely obese men discordant for MetS. A genome-wide differential methylation analysis was conducted in visceral adipose tissue (VAT) of 31 severely obese men discordant for MetS (16 with and 15 without MetS) and identified ∼17,800 variable CpG sites. The genome-wide association study conducted to identify the SNPs (meQTL) associated with methylation levels at variable CpG sites revealed 2292 significant associations (P < 2.22 × 10−11) involving 2182 unique meQTLs regulating the methylation levels of 174 variable CpG sites. Two meQTLs disrupting CpG sites located within the collagen-encoding COL11A2 gene were tested for associations with MetS and its components in a cohort of 3021 obese individuals. Rare alleles of these meQTLs showed association with plasma fasting glucose levels. Further analysis conducted on these meQTL suggested a biological impact mediated through the disruption of transcription factor (TF)–binding sites based on the prediction of TF-binding affinities. The current study identified meQTL in the VAT of severely obese men and revealed associations of two COL11A2 meQTL with fasting glucose levels.
  • Publication
    Accès libre
    Associations between dietary protein sources, plasma BCAA and short-chain acylcarnitine levels in adults
    (M D P I AG, 2019-01-15) Guénard, Frédéric; Garneau, Véronique; Allam-Ndoul, Bénédicte; Pérusse, Louis; Lemieux, Simone; Vohl, Marie-Claude; Rousseau, Michèle
    Elevated plasma branched-chain amino acids (BCAA) and C3 and C5 acylcarnitines (AC) levels observed in individuals with insulin resistance (IR) might be influenced by dietary protein intakes. This study explores the associations between dietary protein sources, plasma BCAA levels and C3 and C5 ACs in normal weight (NW) or overweight (OW) individuals with or without metabolic syndrome (MS). Data from 199 men and women aged 18–55 years with complete metabolite profile were analyzed. Associations between metabolic parameters, protein sources, plasma BCAA and AC levels were tested. OW/MS+ consumed significantly more animal protein (p = 0.0388) and had higher plasma BCAA levels (p < 0.0001) than OW/MS− or NW/MS− individuals. Plasma BCAA levels were not associated with BCAA intakes in the whole cohort, while there was a trend for an association between plasma BCAA levels and red meat or with animal protein in OW/MS+. These associations were of weak magnitude. In NW/MS− individuals, the protein sources associated with BCAA levels varied greatly with adjustment for confounders. Plasma C3 and C5 ACs were associated with plasma BCAA levels in the whole cohort (p < 0.0001) and in subgroups based on OW and MS status. These results suggest a modest association of meat or animal protein intakes and an association of C3 and C5 ACs with plasma BCAA levels, obesity and MS.
  • Publication
    Accès libre
    Impact of NMT1 gene polymorphisms on features of the metabolic syndrome among severely obese patients
    (Openventio Publishers, 2015-11-24) Guénard, Frédéric; Biron, Simon; Biertho, Laurent; Deshaies, Yves; Pérusse, Louis; Lescelleur, Odette; Bégin, Stéphanie; Vohl, Marie-Claude; Tchernof, André; Marceau, Simon
    Introduction: N-myristoyltransferase (NMT) is implicated in myristoylation, required for biological activities of several proteins. Its gene N-myristoyltransferase 1 (NMT1) has been found to be overexpressed and hypermethylated in Visceral Adipose Tissue (VAT) of severely obese individuals with Metabolic Syndrome (MetS+) versus without (MetS-). Objective: The aim of this study was to verify the associations between NMT1 gene polymorphisms Single Nucleotide Polymorphisms (SNPs) and metabolic complications among obese subjects. Methods: Associations between SNPs and determinants of MetS were tested with 1752 obese participants undergoing a bariatric surgery. The effect of selected SNPs on methylation, and correlation with expression levels of NMT1 were verified in subgroups. Results: Rs2239921 was significantly associated with systolic (p=0.03) and diastolic (p<0.0001) blood pressures. Rs2239923 was associated with plasma High Density Lipoprotein-Cholesterol or HDL-Cholesterol (HDL-C) levels (p=0.05), while rs2269746 was associated with Low Density Lipoprotein-Cholesterol or LDL-Cholesterol (LDL-C) (p=0.006) and Total-Cholesterol (Total-C) levels (p=0.004). Rs1005136 (p=0.03), rs8066395 (p=0.03) or rs2157840 (p=0.04) were associated with plasma concentrations of C-Reactive Protein (CRP). Phenotype-associated SNPs were associated with NMT1 methylation levels of six CpG sites. NMT1 methylation levels of one CpG site, cg10755730, correlated with gene expression levels (r=0.57; p=0.04). Conclusion: These results suggest that the presence of NMT1 SNPs is associated with altered plasma lipid levels as well as with increased inflammation markers and blood pressure among severely obese patients.
  • Publication
    A CpG-SNP located within the ARPC3 gene promoter is associated with hypertriglyceridemia in severely obese patients
    (S. Karger AG, 2016-04-08) Guénard, Frédéric; Biron, Simon; Toro Martin, Juan de; Deshaies, Yves; Biertho, Laurent; Pérusse, Louis; Lescelleur, Odette; Vohl, Marie-Claude; Tchernof, André; Marceau, Simon
    Aims: To test the potential association of cytosine-phosphate-guanine dinucleotides (CpG)-single-nucleotide polymorphisms (SNPs) located within actin-related protein 2/3 complex subunit 3 (ARPC3), a gene recently linked to adipogenesis and lipid accumulation, with metabolic syndrome (MetS) features in severely obese patients. Methods: Prioritized SNPs within the ARPC3 locus were genotyped and tested for associations with MetS features in a cohort of 1,749 obese patients with and without MetS. Association testing with CpG methylation levels was performed in a methylation sub-cohort of 16 obese men. Results: A significant association was found between the CpG-SNP rs3759384 (C>T) and plasma triglyceride (TG) levels (false discovery rate-corrected p = 3.5 × 10-2), with 0.6% of the phenotypic variance explained by the CpG-SNP, and with TT homozygotes showing the highest plasma TG levels (1.89 mmol/l). The carriers of the rs3759384 T allele also showed a significant decrease in methylation levels of the ARPC3 promoter-associated CpG site cg10738648 in both visceral adipose tissue and blood. ARPC3 expression levels showed a strong correlation with plasma TG levels (r = 0.70; p = 0.02). Conclusions: The increased plasma TG levels found in homozygous rs3759384 T allele carriers argue for a relevant role of this CpG-SNP in lipid management among obese individuals, which may be driven by an epigenetic-mediated mechanism.