André Tchernof

University Laval, Québec, Quebec, Canada

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Publications (80)303.42 Total impact

  • Article: Accelerometry-measured physical activity and inflammation after gestational diabetes.
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    ABSTRACT: PURPOSE: Gestational diabetes mellitus (GDM) is associated with adverse metabolic outcomes following delivery. Physical activity practice improves the inflammatory profile; however, whether this association exists in women with prior GDM remains unknown. Our objective was to examine cardiometabolic and inflammatory risk factors associated with accelerometer-based measures of physical activity in women with prior GDM. METHODS: Ninety-six women who had GDM between 2003 and 2010 were tested 2.9±2.2 years following delivery. Physical activity practice was measured with Actigraph GT3X accelerometers worn ≥5 days and time spent weekly in moderate to vigorous physical activity (MVPA) was derived. Waist circumference was measured and inflammatory marker or cytokine concentrations were measured in fasting plasma by the xMAP® technology using the Bio-Plex 200 system. The lipid profile was also measured from fasting blood samples. RESULTS: Only 31% of women accumulated at least 150 minutes of MVPA per week. No association was observed between MVPA practice and any of the metabolic measurements in the whole group of women. MVPA did not differ in groups stratified by waist circumference < or ≥88 cm. In women with waist circumference <88 cm, MVPA was negatively correlated with circulating concentrations of CRP (r=-0.51; p=0.006), leptin (r=-0.40; p=0.008), PAI-1 (r=-0.32; p=0.04) and triglycerides (r=-0.44; p=0.003). No association was seen with plasma IL-6, TNF-α and total-, LDL- or HDL- cholesterol concentrations. CONCLUSIONS: These analyses suggest that in the years following delivery, longer time spent in MVPA practice is associated with a lower cardiometabolic risk only in women with prior GDM who do not have abdominal obesity.
    Medicine and science in sports and exercise 03/2013; · 3.71 Impact Factor
  • Article: Markers of macrophage infiltration and measures of lipolysis in human abdominal adipose tissues.
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    ABSTRACT: Objective: We tested the hypothesis that high lipolytic responsiveness is related to increased expression of ATM genes in human adipose tissues. Design and Methods: Omental (OM) and subcutaneous (SC) fat samples were obtained surgically in 46 women (age:47.2±4.7 years, BMI: 26.9±5.2 kg/m(2) ). Body composition and fat distribution were measured by dual energy x-ray absorptiometry and computed tomography. Lipolysis was measured by glycerol release in mature adipocytes isolated by collagenase digestion under basal-, isoproterenol (10(-5) M)- and forskolin (10(-5) M)-stimulated conditions. Quantification of macrophage gene mRNA expression (CD11b, CD11c and CD68) in whole adipose tissue was performed by real-time RT-PCR. Results: SC CD68 mRNA abundance was positively associated with isoproterenol-stimulated lipolysis (r=0.36, p<0.05). This association remained significant after adjustment for total body fat mass (r=0.34, p<0.05). In the OM depot, CD11b mRNA abundance was positively associated with isoproterenol-stimulated lipolysis (r=0.42, p≤0.005). This association remained significant after adjustment for total body fat mass (r=0.41, p<0.01). In subgroup analyses, high lipolytic rates in SC adipocytes were related to increased whole tissue expression of CD68 and CD11b in this compartment, independent of adiposity and fat cell size (p≤0.001 and p≤0.05). High lipolytic rates in OM adipocytes were related to increased whole tissue OM expression of CD11b, independent of adiposity and fat cell size (p<0.05). Conclusions: High adipocyte lipolytic responsiveness is related to increased expression of ATM markers in the corresponding compartment, independent of adiposity and fat cell size.
    Obesity 02/2013; · 4.28 Impact Factor
  • Article: Comparison of the dipeptidyl peptidase-4 gene methylation levels between severely obese subjects with and without the metabolic syndrome.
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    ABSTRACT: BACKGROUND: The dipeptidyl peptidase-4 (DPP4) enzyme is a novel adipokine potentially involved in the development of the metabolic syndrome (MetS). Previous observations demonstrated higher visceral adipose tissue (VAT) DPP4 gene expression in non-diabetic severely obese men with (MetS+) vs. without (MetS-) MetS. DPP4 mRNA abundance in VAT correlated also with CpG site methylation levels (%Meth) localized within and near its exon 2 (CpG94 to CpG102) in non-diabetic severely obese women, regardless of their MetS status. The actual study tested whether DPP4%Meth levels in VAT are different between MetS- and MetS+ non-diabetic severely obese subjects, whether variable metabolic and plasma lipid profiles are observed between DPP4%Meth quartiles, and whether correlation exists in DPP4%Meth levels between VAT and white blood cells (WBCs). METHODS: DNA was extracted from the VAT of 26 men (MetS-: n=12, MetS+: n=14) and 79 women (MetS-: n=60; MetS+: n=19), as well as from WBCs in a sub-sample of 17 women (MetS-: n=9; MetS+: n=8). The%Meth levels of CpG94 to CpG102 were assessed by pyrosequencing of sodium bisulfite-treated DNA. ANOVA analyses were used to compare the%Meth of CpGs between MetS- and MetS+ groups, and to compare the metabolic phenotype and plasma lipid levels between methylation quartiles. Pearson correlation coefficient analyses were computed to test the relationship between VAT and WBCs CpG94-102%Meth levels. RESULTS: No difference was observed in CpG94-102%Meth levels between MetS- and MetS+ subjects in VAT (P=0.67), but individuals categorized into CpG94-102%Meth quartiles had variable plasma total-cholesterol concentrations (P=0.04). The%Meth levels of four CpGs in VAT were significantly correlated with those observed in WBCs (r=0.55-0.59, P<=0.03). CONCLUSIONS: This study demonstrated that%Meth of CpGs localized within and near the exon 2 of the DPP4 gene in VAT are not associated with MetS status. The actual study also revealed an association between the%Meth of this locus with plasma total-cholesterol in severe obesity, which suggests a link between the DPP4 gene and plasma lipid levels.
    Diabetology and Metabolic Syndrome 02/2013; 5(1):4. · 1.53 Impact Factor
  • Article: Pathophysiology of human visceral obesity: an update.
    André Tchernof, Jean-Pierre Després
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    ABSTRACT: Excess intra-abdominal adipose tissue accumulation, often termed visceral obesity, is part of a phenotype including dysfunctional subcutaneous adipose tissue expansion and ectopic triglyceride storage closely related to clustering cardiometabolic risk factors. Hypertriglyceridemia; increased free fatty acid availability; adipose tissue release of proinflammatory cytokines; liver insulin resistance and inflammation; increased liver VLDL synthesis and secretion; reduced clearance of triglyceride-rich lipoproteins; presence of small, dense LDL particles; and reduced HDL cholesterol levels are among the many metabolic alterations closely related to this condition. Age, gender, genetics, and ethnicity are broad etiological factors contributing to variation in visceral adipose tissue accumulation. Specific mechanisms responsible for proportionally increased visceral fat storage when facing positive energy balance and weight gain may involve sex hormones, local cortisol production in abdominal adipose tissues, endocannabinoids, growth hormone, and dietary fructose. Physiological characteristics of abdominal adipose tissues such as adipocyte size and number, lipolytic responsiveness, lipid storage capacity, and inflammatory cytokine production are significant correlates and even possible determinants of the increased cardiometabolic risk associated with visceral obesity. Thiazolidinediones, estrogen replacement in postmenopausal women, and testosterone replacement in androgen-deficient men have been shown to favorably modulate body fat distribution and cardiometabolic risk to various degrees. However, some of these therapies must now be considered in the context of their serious side effects. Lifestyle interventions leading to weight loss generally induce preferential mobilization of visceral fat. In clinical practice, measuring waist circumference in addition to the body mass index could be helpful for the identification and management of a subgroup of overweight or obese patients at high cardiometabolic risk.
    Physiological Reviews 01/2013; 93(1):359-404. · 26.87 Impact Factor
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    Article: Relationship between the adoption of preventive practices and the metabolic profile of women with prior gestational diabetes mellitus.
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    ABSTRACT: Women with prior gestational diabetes mellitus (GDM) are encouraged to adopt healthy lifestyle behaviours to prevent or delay type 2 diabetes. The objective was to examine the association between the adoption of preventive practices and the metabolic profile of women with prior GDM. Analyses included 181 women who had GDM between 2003 and 2010. The preventive practices examined included (i) regular physical activity (≥150 min·week(-1)) assessed with the International Physical Activity Questionnaire; (ii) a healthy diet (score derived from the Alternate Healthy Eating Index and associated with a lower metabolic risk) evaluated from a food frequency questionnaire; and (iii) exclusive breastfeeding (≥6 months). Women were classified according to the number of preventive practices adopted. Waist circumference, weight, and height were measured and body mass index (BMI) was calculated. Fasting insulinemia and glycemia were obtained and Matsuda index for insulin sensitivity was calculated. Nearly one-third of women adopted none of the listed preventive practices. For each increase of 1 preventive practice adopted, women were 30% less likely to have a BMI ≥ 25 kg·m(-2) (odds ratio (OR): 0.70, 95% confidence interval (CI) (0.50-0.98)), they were 34% less likely to have a waist circumference ≥ 88 cm (OR: 0.66, 95%CI (0.47-0.92)) and they were 33% less likely to have a Matsuda index for insulin sensitivity < 9.69 (OR: 0.67, 95%CI (0.48-0.94)). These results suggest that women with prior GDM who adopt the recommended preventive practices in the years following delivery are less likely to have lower insulin sensitivity, less likely to be overweight-obese, and less likely to be characterized by abdominal obesity.
    Applied Physiology Nutrition and Metabolism 12/2012; 37(6):1232-8. · 2.13 Impact Factor
  • Article: Androgens in the maternal and fetal circulation: association with insulin resistance.
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    ABSTRACT: Abstract Objective: To examine maternal insulin resistance in relationship with maternal and fetal androgen levels as well as with term placenta mRNA and protein abundance of steroidogenic enzymes implicated in androgen dynamics. Methods: The study included 20 women with gestational diabetes mellitus and 27 controls tested using a 120 min., 75g oral glucose tolerance test. Maternal and fetal plasma concentrations of total testosterone, dihydrotestosterone (DHT) and dehydroepiandrosterone (DHEA) were measured by high-performance gas chromatography and chemical ionization mass spectrometry at 26.1±3.7 weeks of pregnancy. Results: Glycemic response to oral glucose over 120 min. as well as Matsuda insulin sensitivity and HOMA insulin resistance (HOMA-IR) indices were significantly associated with testosterone levels (r=0.31, r=-0.37 and r=0.35 respectively, p≤0.05 for all). Among male offspring, a positive association between maternal and fetal testosterone levels was observed (r=0.43, p≤0.05). Testosterone levels were higher in the cord blood of newborns from insulin resistant mothers compared to newborns from insulin sensitive mothers (0.48±0.36 nmol/L vs. 0.29±0.18 nmol/L p≤0.05). No difference was observed in mRNA abundance or protein expression of placental steroidogenic enzymes according to the degree of maternal insulin resistance. Conclusion: Our results demonstrate a possible association between fetal and maternal androgen concentrations in relationship with insulin resistance.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 10/2012; · 1.36 Impact Factor
  • Article: Impact of Gastrointestinal Surgery on Cardiometabolic Risk.
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    ABSTRACT: Bariatric surgery has gained acceptance as the only treatment with long-term efficacy for severe obesity. Recent publications emphasize the usefulness of bariatric surgery in the reduction of long-term cardiometabolic risk, cardiovascular disease incidence and mortality, and the management of uncontrolled type 2 diabetes (T2DM), an important cardiovascular risk factor in individuals with severe obesity. The present review article offers a brief overview of the literature published over the past several months relevant to cardiometabolic outcomes in bariatric surgery patients. A recent report from the Swedish Obese Subjects (SOS) study specifically reported a reduced incidence of cardiovascular events on long-term prospective follow-up after bariatric surgery. In addition, abundant studies have been recently published on gastric bypass surgery showing high T2DM remission rates as well as improved blood lipids and inflammatory markers after surgery. Sleeve gastrectomy is increasingly performed as a stand-alone operation. Recent reports on this surgery pertaining to cardiometabolic risk showed variable T2DM remission rates that may possibly be explained by age of the patients and duration of T2DM. Available data suggest a possible favorable impact of the surgery on CRP levels and improvements in the blood lipid profile. How sleeve gastrectomy compares to other surgical approaches will require further study. Biliopancreatic diversion with duodenal switch has been reported to offer some of the best long-term weight loss for obese patients. Approximately 9 out of 10 patients treated with this surgical procedure show long-term remission rates of T2DM. Significant improvements in the cardiometabolic risk profile are also observed after BPD-DS; they are especially pronounced regarding dyslipidemia. In conclusion, bariatric procedures improve the cardiometabolic risk profile, a phenomenon that appears to be only partly explained by the magnitude of the weight loss. Significant variations are observed with respect to the type of surgery and patient characteristics. More research is clearly needed on the short and long-term cardiometabolic outcome of obesity surgeries.
    Current Atherosclerosis Reports 10/2012; · 2.66 Impact Factor
  • Article: Cord blood C-peptide levels relate to the metabolic profile of women with and without gestational diabetes.
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    ABSTRACT: Plasma C-peptide reflects the insulin-secretory activity of pancreatic β-cells which modulates fetal growth. Cord blood C-peptide levels were measured in women with gestational diabetes mellitus (GDM) and in women with normal glucose tolerance (NGT). Forty-one women underwent a 75g oral glucose tolerance test (18 GDM, 23 NGT). Cord blood C-peptide (p= 0.09) and glucose levels (p= 0.08) from newborns of GDM women tended to be higher compared to those from NGT women. In the entire group, cord blood C-peptide correlated with maternal insulin, fasting C-peptide, insulin sensitivity, interleukin-6, weight and body mass index measured at screening (ρ from 0.34 to 0.48, all p<0.05) and tended to correlate with offspring weight (ρ= 0.28, p= 0.08). Newborns of GDM women tended to have elevated cord blood C-peptide which correlated with maternal insulin, insulin sensitivity and anthropometric measures at diagnosis and with offspring characteristics. This suggests that insulin-secretory activity of the newborn is related to maternal metabolic parameters.
    Acta Obstetricia Et Gynecologica Scandinavica 09/2012; · 1.77 Impact Factor
  • Article: Transcriptomic and metabolomic signatures of an n-3 polyunsaturated fatty acids supplementation in a normolipidemic/normocholesterolemic Caucasian population.
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    ABSTRACT: OMIC technologies, including transcriptomics and metabolomics, may provide powerful tools for identifying the effects of nutrients on molecular functions and metabolic pathways. The objective was to investigate molecular and metabolic changes following n-3 polyunsaturated fatty acid (PUFA) supplementation in healthy subjects via traditional biomarkers as well as transcriptome and metabolome analyses. Thirteen men and 17 women followed a 2-week run-in period based on Canada's Food Guide and then underwent 6-week supplementation with n-3 PUFA (3 g/day). Traditional biochemical markers such as plasma lipids, inflammatory markers, glycemic parameters and erythrocyte fatty acid concentrations were measured. Changes in gene expression of peripheral blood mononuclear cells were assessed by microarrays, and metabolome profiles were assessed by mass spectrometry assay kit. After supplementation, plasma triglycerides decreased and erythrocyte n-3 PUFA concentrations increased to a similar extent in both genders. Further, plasma high-density lipoprotein cholesterol concentrations and fasting glucose levels increased in women after n-3 PUFA supplementation. N-3 PUFA supplementation changed the expression of 610 genes in men, whereas the expression of 250 genes was altered in women. Pathway analyses indicate changes in gene expression of the nuclear receptor peroxisome proliferator-activated receptor-alpha, nuclear transcription-factor kappaB, oxidative stress and activation of the oxidative stress response mediated by nuclear factor (erythroid-derived 2)-like 2. After n-3 PUFA supplementation, metabolomics profiles demonstrate an increase in acylcarnitines, hexose and leucine in men only and a decrease in saturation of glycerophosphatidylcholine and lysophosphatidylcholine concentrations in all subjects. Overall, traditional and novel biomarkers suggest that n-3 PUFA supplementation exerts cardioprotective effects.
    The Journal of nutritional biochemistry 06/2012; · 4.29 Impact Factor
  • Article: Thymic stromal lymphopoietin: an immune cytokine gene associated with the metabolic syndrome and blood pressure in severe obesity.
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    ABSTRACT: A previous expression profiling of VAT (visceral adipose tissue) revealed that the TSLP (thymic stromal lymphopoietin) gene was less expressed in severely obese men with (n=7) compared with without (n=7) the MetS (metabolic syndrome). We hypothesized that TSLP SNPs (single nucleotide polymorphisms) are associated with TSLP gene expression in VAT and with MetS phenotypes. Following validation of lower TSLP expression (P=0.003) in VAT of severely obese men and women with (n=70) compared with without (n=60) the MetS, a detailed genetic investigation was performed at the TSLP locus by sequencing its promoter, exons and intron-exon splicing boundaries using DNA of 25 severely obese subjects. Five tagging SNPs were genotyped in the 130 subjects from the expression analysis to test whether these SNPs contributed to TSLP expression variability (ANOVAs) and then genotyped in two independent samples of severely obese men (total, n=389) and women (total, n=894). In a sex-stratified multistage experimental design, ANOVAs were performed to test whether tagging SNPs were associated with MetS components treated as continuous variables. We observed that the non-coding SNP rs2289277 was associated with TSLP mRNA abundance (P=0.04), as well as with SBP [systolic BP (blood pressure)] (P=0.004) and DBP (diastolic BP) (P=0.0003) in men when adjusting for age, waist circumference, smoking and medication treating hypertension. These novel observations suggest that TSLP expression in VAT may partly explain the inter-individual variability for metabolic impairments in the presence of obesity and that specific SNPs (rs2289277 and/or correlating SNPs) may influence TSLP gene expression as well as BP in obese men.
    Clinical Science 02/2012; 123(2):99-109. · 4.61 Impact Factor
  • Article: Impact of a mother's weight history on her offspring.
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    ABSTRACT: To explore the relationship between maternal lifelong body weight history and anthropometric measurements in the offspring. We studied a prospective sample of 48 pregnant women with either gestational diabetes mellitus (GDM, n = 21) or normal glucose tolerance (NGT, n = 27). Reported maternal weight at birth, 20 years of age and 30 years of age, and pre-pregnancy and maximal weight outside pregnancy were obtained by questionnaire. BMI was calculated using data from the questionnaire. Maternal anthropometric parameters were measured during pregnancy. Offspring anthropometrics were obtained at birth and eight weeks later. Maternal weight at birth, weight or BMI at 20 years of age and at 30 years of age, and maximal weight or BMI did not differ between groups. In all women, maternal birth weight, BMI at 20 years of age, and maximal BMI correlated with newborn birth weight (ρ = 0.39, 0.37, and 0.27, respectively, P ≤ 0.05), with newborn length (ρ = 0.46, 0.32, and 0.30 respectively, P < 0.05), and with infant weight eight weeks later (ρ = 0.43, 0.30, and 0.31, respectively, P < 0.05). Reported maternal BMI at 30 years of age correlated with infant weight (ρ = 0.31) and cranial circumference (ρ = 0.33) at eight weeks of life (P < 0.05). Besides gestational age, maternal weight at screening was the most significant predictor of infant birth weight. Several parameters of maternal weight history were related to offspring anthropometric measurements in early life in a sample of women with and without GDM.
    Journal of obstetrics and gynaecology Canada: JOGC = Journal d'obstetrique et gynecologie du Canada: JOGC 01/2012; 34(1):34-8.
  • Article: Visceral fat accumulation is an indicator of adipose tissue macrophage infiltration in women.
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    ABSTRACT: We tested the hypothesis that visceral obesity is the best correlate of abdominal adipose tissue macrophage infiltration in women. Omental and subcutaneous fat samples were surgically obtained from 40 women (age, 47.0 ± 4.0 years; body mass index, 28.4 ± 5.8 kg/m(2)). CD68+ cells were identified using fluorescence immunohistochemistry. Expression of macrophage markers was measured by real-time reverse transcriptase polymerase chain reaction. Body composition and fat distribution were measured by dual-energy x-ray absorptiometry and computed tomography, respectively. Mean CD68+ cell percentage tended to be higher in subcutaneous (18.3%) compared with omental adipose tissue (15.5%, P = .07). Positive correlations were observed between CD68+ cell percentage as well as CD68 messenger RNA expression in a given depot vs the other (P ≤ .01). Visceral adipose tissue area and omental adipocyte diameter were positively related to CD68+ cell percentage in omental fat (r = 0.52 and r = 0.35, P ≤ .05). Total and visceral adipose tissue areas as well as subcutaneous adipocyte diameter were significantly correlated with CD68+ cell percentage in subcutaneous adipose tissue (0.32 ≤ r ≤ 0.40, P ≤ .05). Adipose tissue areas and subcutaneous adipocyte diameter were also significantly associated with expression of commonly used macrophage markers including CD68 in the subcutaneous fat compartment (0.32 ≤ r ≤ 0.57, P ≤ .05). Visceral adipose tissue area was the best correlate of CD68+ cell percentage in both omental and subcutaneous fat tissues, explaining, respectively, 20% and 12% of the variance in models also including subcutaneous adipose tissue area, adipocyte sizes, and total body fat mass. Visceral adipose tissue accumulation is the best correlate of macrophage infiltration in both the subcutaneous and omental fat compartments of lean to obese women.
    Metabolism: clinical and experimental 12/2011; 61(5):689-98. · 2.59 Impact Factor
  • Article: Genetic contribution to C-reactive protein levels in severe obesity.
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    ABSTRACT: Obese individuals are characterized by a chronic, low-grade inflammatory state. Increased levels of C-reactive protein (CRP), a marker of inflammation, have been observed in subjects with the metabolic syndrome. We have previously reported that genes encoding proteins involved in the anti-inflammatory and immune response are differentially expressed in visceral adipose tissue of obese men with or without the metabolic syndrome. Among these genes, the interferon-gamma-inducible protein 30 (IFI30), CD163 molecule (CD163), chemokine (C-X-C motif) ligand 9 (CXCL9) and thymic stromal lymphopoietin (TSLP), were selected for further genetic analyses. The aim of the study was to verify whether IFI30, CD163, CXCL9 and TSLP gene polymorphisms contribute to explain the inter-individual variability of the inflammatory profile of obesity assessed by plasma high-sensitivity CRP concentrations. A total of 1185 severely obese individuals were genotyped for single nucleotide polymorphisms (SNPs) covering most of the sequence-derived genetic variability at the IFI30, CD163, CXCL9 and TSLP gene loci (total of 27 SNPs). Following measurement of plasma CRP levels, subjects were divided into two groups, low vs. high using the median value of plasma CRP levels (8.31 mg/L) as a cutoff point. Genotype frequencies were compared between groups. Associations between genotypes and plasma CRP levels (continuous variable) were also tested after adjustments for age, sex, smoking and BMI. The rs11554159 and rs7125 IFI30 SNPs showed a significant difference in genotype frequencies (p<0.05) between subgroups of low vs. high plasma CRP levels (wild type homozygotes: rs11554159=47% vs. 55%, rs7125=31% vs. 24%, for low vs. high CRP groups, respectively). The association between rs11554159 and CRP levels as a continuous variable remained significant (p=0.004). Both carriers of the GA and AA genotypes demonstrated, on average, a 13% lower CRP levels in comparison with GG homozygotes. No association was observed between SNPs in the CD163, CXCL9 and TSLP genes and CRP levels. The IFI30 rs11554159 polymorphism could partially explain the inter-individual variability observed in the inflammatory profile associated with obesity.
    Molecular Genetics and Metabolism 12/2011; 105(3):494-501. · 3.19 Impact Factor
  • Article: Evaluation of fetal liver volume by tridimensional ultrasound in women with gestational diabetes mellitus.
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    ABSTRACT: To evaluate the effect of gestational diabetes mellitus (GDM) on fetal liver growth during the third trimester. We performed a longitudinal study of pregnant women recruited at the time of GDM screening (24 to 28 weeks of gestation), with follow-up visits at 32 weeks, 36 weeks, and delivery. Women with GDM were followed with nutritional recommendations and insulin when necessary according to the Canadian Diabetes Association guidelines. Fetal liver volume was evaluated using 3-D ultrasound at each antenatal visit, and fetal liver growth was compared between women with and without GDM. Twenty-seven women were recruited, 10 with normal glucose tolerance (NGT) and 17 with confirmed GDM, five who required insulin and 12 who were treated by diet only. We found no difference in fetal liver volume between groups at any of the three visits, and median birth weight was also similar between groups. On the other hand, we found a strong correlation between fetal liver volume at 36 weeks' gestation and birth weight (ρ = 0.61, P < 0.001). In our preliminary study, we found that fetal liver volume could be a strong predictor of infant birth weight independent of GDM status. This suggests that fetal liver volume of offspring of women with NGT is similar to that of offspring of women with GDM treated following recommended targets. Larger studies are required.
    Journal of obstetrics and gynaecology Canada: JOGC = Journal d'obstetrique et gynecologie du Canada: JOGC 11/2011; 33(11):1095-8.
  • Article: Elevated serum 25(OH)D concentrations, vitamin D, and calcium intakes are associated with reduced adipocyte size in women.
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    ABSTRACT: Recent studies have suggested a beneficial effect of vitamin D and calcium on adipocyte metabolism and the metabolic profile. Our objective was to examine associations of vitamin D intake, calcium and dairy products as well as serum 25(OH)D concentration with adiposity measures and adipocyte size in women. Omental and subcutaneous adipose tissue samples were obtained from 43 women undergoing gynecological surgeries. Adipocyte size was measured using adipocyte suspensions from collagenase-digested fat tissues. Total and visceral adiposity were assessed by dual-energy X-ray absorptiometry and computed tomography, respectively. Serum 25(OH)D was measured by radioimmmunoassay. Dietary intakes were assessed using a food frequency questionnaire. Women consuming two or more dairy product portions daily had smaller adipocytes in the omental depot compared to women consuming less than two portions daily (79 ± 12 vs. 94 ± 16 µm, P ≤ 0.01). Dietary intakes of calcium (r = -0.55) and vitamin D (r = -0.43) as well as serum 25(OH)D (r = -0.35) were also inversely and significantly associated with omental adipocyte size (P ≤ 0.05 for all). Dietary vitamin D intake was inversely associated with visceral adipose tissue area (r = -0.34, P ≤ 0.05). Serum 25(OH)D was also inversely associated with visceral adipose tissue area (r = -0.32) as well as with total adipose tissue area (r = -0.44), subcutaneous adipose tissue area (r = -0.36), BMI (r =-0.43) and total body fat mass (r = -0.41, P ≤ 0.05 for all). In conclusion, elevated dietary vitamin D intake and serum 25(OH)D values are related to lower visceral adiposity and omental adipocyte size in women.
    Obesity 04/2011; 19(7):1335-41. · 4.28 Impact Factor
  • Article: Sex hormone-binding globulin levels and obesity in women with gestational diabetes: relationship with infant birthweight.
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    ABSTRACT: Our objective was to determine whether sex hormone-binding globulin (SHBG) concentrations are associated with gestational diabetes mellitus (GDM) and whether this association is independent of prepregnancy body mass index (BMI). The relationship between maternal SHBG concentrations and birthweight in the offspring was also examined. The study included 47 women (20 with GDM, 27 controls). GDM screening and fasting serum SHBG measurements were performed at 26.1 ± 3.7 weeks of pregnancy. A trend was observed for significantly lower SHBG concentrations in GDM patients (179 ± 36 vs. 195 ± 36 nmol/l, p ≤ 0.08). Prepregnancy BMI and BMI at the time of GDM screening were both correlated with SHBG concentrations (r = -0.49 and r =  -0.53, respectively; p ≤ 0.001). In multivariate regression analyses, only prepregnancy BMI or BMI at the time of GDM screening remained significant predictors of GDM risk [odds ratio (OR):1.23, 95% confidence interval (CI):1.06-1.47, p ≤ 0.01 and OR:1.18, 95% CI:1.02-1.39, p ≤ 0.02] while SHBG level did not. On the other hand, 10.7% of the variance in birthweight was explained by SHBG concentrations (p ≤ 0.01) independent of the presence of GDM, parity, maternal age, maternal prepregnancy BMI, maternal height, and offspring sex. In conclusion, although SHBG concentration is not an independent predictor of GDM risk when obesity is considered, it is a significant predictor of infant birthweight independent of GDM and prepregnancy BMI.
    Gynecological Endocrinology 04/2011; 27(11):905-9. · 1.58 Impact Factor
  • Article: Circulating interleukin‐6 concentrations during and after gestational diabetes mellitus
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    ABSTRACT: Objective. Recent studies have shown that high interleukin-6 (IL-6) secretion may aggravate insulin resistance in pregnancy and participate in the pathogenesis of gestational diabetes mellitus (GDM). The aim of this study was to determine whether the presence of GDM is associated with elevated IL-6 concentrations and whether this association remains after delivery, independent of body mass index. Design. Longitudinal study. Setting. Hospital-based. Sample. Forty-seven women were screened for GDM with a 75g oral glucose tolerance test at 26.1±3.7 weeks of pregnancy following the Canadian Diabetes Association guidelines (20 GDM, 27 control subjects). Main outcome measures. Interleukin-6 levels were measured by ELISA at the time of GDM screening and two months post-partum. Results. Interleukin-6 concentrations were significantly higher in women with GDM compared with control women at the time of GDM screening (1.47±0.72 vs. 0.90±0.32pg/mL, p≤0.01). Similar results were obtained two months post-partum, where IL-6 levels remained significantly higher in women with GDM compared with control women (1.88±0.85 vs. 1.41±0.87pg/mL, p≤0.05). Interleukin-6 concentrations were significantly correlated with the Matsuda insulin sensitivity index, measured at the two time points (r=–0.60, p≤0.01 and r=–0.34, p≤0.05). The Matsuda insulin sensitivity index was an independent and significant predictor of IL-6 concentrations at the time of GDM screening, explaining 35.6% of the variance (p≤0.0001) in this variable. IL-6 concentration measured at GDM screening was identified as an independent and significant predictor of post-partum IL-6 concentrations, explaining 28.6% of the variance (p≤0.001). Conclusions. These results show that GDM is associated with elevated IL-6 levels independent of obesity levels, both during pregnancy and after delivery.
    Acta Obstetricia Et Gynecologica Scandinavica 03/2011; 90(5):524 - 530. · 1.77 Impact Factor
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    Article: Visceral adipocyte hypertrophy is associated with dyslipidemia independent of body composition and fat distribution in women.
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    ABSTRACT: We assessed whether subcutaneous and omental adipocyte hypertrophy are related to metabolic alterations independent of body composition and fat distribution in women. Mean adipocyte diameter of paired subcutaneous and omental adipose tissue samples was obtained in lean to obese women. Linear regression models predicting adipocyte size in both adipose tissue depots were computed using body composition and fat distribution measures (n = 150). In a given depot, women with larger adipocytes than predicted by the regression were considered as having adipocyte hypertrophy, whereas women with smaller adipocytes than predicted were considered as having adipocyte hyperplasia. Women characterized by omental adipocyte hypertrophy had higher plasma and VLDL triglyceride levels as well as a higher total-to-HDL cholesterol ratio compared with women characterized by omental adipocyte hyperplasia (P < 0.05). Conversely, women characterized by subcutaneous adipocyte hypertrophy or hyperplasia showed a similar lipid profile. In logistic regression analyses, a 10% enlargement of omental adipocytes increased the risk of hypertriglyceridemia (adjusted odds ratio [OR] 4.06, P < 0.001) independent of body composition and fat distribution measures. A 10% increase in visceral adipocyte number also raised the risk of hypertriglyceridemia (adjusted OR 1.55, P < 0.02). Associations between adipocyte size and homeostasis model assessment of insulin resistance were not significant once adjusted for adiposity and body fat distribution. These results suggest that omental, but not subcutaneous, adipocyte hypertrophy is associated with an altered lipid profile independent of body composition and fat distribution in women.
    Diabetes 03/2011; 60(5):1504-11. · 8.29 Impact Factor
  • Article: DPP4 gene DNA methylation in the omentum is associated with its gene expression and plasma lipid profile in severe obesity.
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    ABSTRACT: Severely obese subjects with the metabolic syndrome (MS) have higher dipeptidyl peptidase-4 (DPP4) expression in their visceral adipose tissue (VAT) compared to obese individuals without MS. We tested the hypothesis that methylation level of CpG sites in the DPP4 promoter CpG island in VAT was genotype-dependent and associated with DPP4 mRNA abundance and MS-related phenotypes. The VAT DNA was extracted in 92 severely obese premenopausal women undergoing biliopancreatic derivation for the treatment of obesity. Women were nondiabetic and none of them used medication to treat MS features. Cytosine methylation rates (%) of 102 CpG sites in the DPP4 CpG island were assessed by pyrosequencing of sodium bisulfite-treated DNA. Methylation rates were >10% for CpG sites 94-102. Their mean methylation rate (%Meth(94-102)) was different between genotypes for DPP4 polymorphisms rs13015258 (P = 0.001), rs17848915 (P = 0.0004), and c.1926 G>A (P = 0.001). The %Meth(94-102) correlated negatively with DPP4 mRNA abundance (r = -0.25, P < 0.05) and positively with plasma high-density lipoprotein (HDL) cholesterol concentrations (r = 0.22, P < 0.05), whereas DPP4 mRNA abundance correlated positively with plasma total-/HDL-cholesterol ratio (r = 0.25; P < 0.05). In the VAT of nondiabetic severely obese women, genotype-dependent methylation levels of specific CpG sites in the DPP4 promoter CpG island were associated with DPP4 gene expression and variability in the plasma lipid profile. Higher DPP4 gene expression in VAT and its relationship with the plasma lipid profile may be explained by actually unknown DPP4 biological effect or, to another extent, may also be a marker of VAT inflammation known to be associated with metabolic disturbances.
    Obesity 02/2011; 19(2):388-95. · 4.28 Impact Factor
  • Article: Circulating interleukin-6 concentrations during and after gestational diabetes mellitus.
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    ABSTRACT: Recent studies have shown that high interleukin-6 (IL-6) secretion may aggravate insulin resistance in pregnancy and participate in the pathogenesis of gestational diabetes mellitus (GDM). The aim of this study was to determine whether the presence of GDM is associated with elevated IL-6 concentrations and whether this association remains after delivery, independent of body mass index. Longitudinal study. Hospital-based. Forty-seven women were screened for GDM with a 75g oral glucose tolerance test at 26.1±3.7 weeks of pregnancy following the Canadian Diabetes Association guidelines (20 GDM, 27 control subjects). Interleukin-6 levels were measured by ELISA at the time of GDM screening and two months post-partum. Interleukin-6 concentrations were significantly higher in women with GDM compared with control women at the time of GDM screening (1.47±0.72 vs. 0.90±0.32pg/mL, p≤0.01). Similar results were obtained two months post-partum, where IL-6 levels remained significantly higher in women with GDM compared with control women (1.88±0.85 vs. 1.41±0.87pg/mL, p≤0.05). Interleukin-6 concentrations were significantly correlated with the Matsuda insulin sensitivity index, measured at the two time points (r=-0.60, p≤0.01 and r=-0.34, p≤0.05). The Matsuda insulin sensitivity index was an independent and significant predictor of IL-6 concentrations at the time of GDM screening, explaining 35.6% of the variance (p≤0.0001) in this variable. IL-6 concentration measured at GDM screening was identified as an independent and significant predictor of post-partum IL-6 concentrations, explaining 28.6% of the variance (p≤0.001). These results show that GDM is associated with elevated IL-6 levels independent of obesity levels, both during pregnancy and after delivery.
    Acta Obstetricia Et Gynecologica Scandinavica 02/2011; 90(5):524-30. · 1.77 Impact Factor

Institutions

  • 2006–2013
    • University Laval
      • Institut des Nutraceutiques et des Aliments Fonctionnels (INAF)
      Québec, Quebec, Canada
  • 2012
    • Institut Universitaire de Cardiologie et de Pneumologie de Québec (Hôpital Laval)
      Québec, Quebec, Canada
  • 2009
    • Université du Québec à Chicoutimi
      Saguenay, Quebec, Canada
  • 2007
    • University of Sydney
      Sydney, New South Wales, Australia
  • 2002–2006
    • University of Vermont
      • Department of Medicine
      Burlington, VT, USA
  • 2003
    • Université de Montréal
      Montréal, Quebec, Canada