Biomedical subjects

Charles Couillard

Publications and source records attributed to Charles Couillard.

22 records · Page 2Linked to original sources

PubMed2003

Contribution of visceral adiposity to the exaggerated postprandial lipemia of men with impaired glucose tolerance.

OBJECTIVE: Impaired glucose tolerance (IGT) has been associated with alterations in numerous coronary heart disease risk factors, including postprandial hyperlipidemia. An excess visceral adipose tissue accumulation is also predictive of IGT and of an exaggerated postprandial lipemia. The objective of the present study was therefore to compare the respective contributions of visceral adipose tissue accumulation versus IGT with the variation in postprandial lipemia. RESEARCH DESIGN AND METHODS: Potential differences in postprandial triglyceride (TG)-rich lipoprotein (TRL) levels following a standardized breakfast with a high fat content were examined among men characterized by normal glucose tolerance (NGT) or IGT. Sixty-seven men were classified according to their glucose tolerance status (<7.8 mmol/l [NGT] or between 7.8 and 11.1 mmol/l [IGT] 2 h after a 75-g oral glucose test). RESULTS: Men with IGT showed the highest TRL-TG concentrations (P < 0.05) at the 4-, 6-, and 8-h time points compared with men with NGT. These higher postprandial TRL-TG levels among men with IGT were also accompanied by a greater postprandial TG total area under the incremental curve in all TRL fractions (large, medium, and small) (P < 0.05). Furthermore, subjects characterized by IGT had also the highest visceral adipose tissue accumulation (P < 0.009). When subgroups of IGT and NGT men were individually matched (n = 11) for similar visceral adipose tissue accumulation, no significant difference was found in postprandial responses of all TRL-TG fractions between the two groups. CONCLUSIONS: These results provide evidence that visceral adipose tissue accumulation is an important factor involved in the deterioration of postprandial lipemia noted among men with IGT.

Adipose Tissue↗

PubMed2002

HDL particle size: a marker of the gender difference in the metabolic risk profile.

A low plasma HDL-cholesterol concentration is an important risk factor for coronary heart disease (CHD) and is often accompanied by increased triglyceride concentrations. Women have generally higher HDL-cholesterol and lower triglyceride concentrations and concomitantly are at lower risk of CHD than men. As HDL particle size is a new and potentially important marker of CHD risk, we have examined the potential gender difference in HDL particle size, assessed by nondenaturing 4-30% polyacrylamide gradient gel electrophoresis, in a sample of men (n=231) and women (n=183). Overall, men were characterized by a less favorable lipoprotein--lipid profile, which was accompanied by smaller HDL particle size compared to women. However, when men and women were matched for HDL particle size and compared for their metabolic profile, it was found that both genders were characterized by similar plasma lipoprotein--lipid profile despite the fact that women were characterized by higher levels of total body fat but lower waist girth than men. In summary, HDL particle size is a strong marker of the gender-related difference in the determination of the metabolic risk profile.

Adolescent↗

PubMed2002

Plasma leptin response to an epinephrine infusion in lean and obese women.

OBJECTIVE: Because leptin production by adipose tissue is under hormonal control, we examined the impact of epinephrine administration on plasma leptin concentrations. RESEARCH METHODS AND PROCEDURES: We measured plasma leptin, insulin, and free fatty acid (FFA) responses after a 60-minute epinephrine infusion (0.010 microg/kg fat free mass/min) followed by a 30-minute recovery period (no infusion) in a group of 11 lean (mean body mass index +/- SD: 22.6 +/- 1.1 kg/m(2)) and 15 obese (30.0 +/- 1.3 kg/m(2)) premenopausal women. Leptin, insulin, and FFA levels were measured in plasma before (-15 and 0 minutes) and at every 30 minutes over the 90-minute period. RESULTS: In both lean and obese individuals, plasma leptin was significantly reduced by epinephrine (p < 0.0001). Body fat mass was associated with fasting leptin levels (r = 0.64, p < 0.0005) as well as with the decrease in leptinemia (r = -0.51, p < 0.01) produced by epinephrine administration. Furthermore, we noted a large range of leptin response to epinephrine among our subjects, especially in obese women (from -12 to -570 ng/mL per 60 minutes). However, there was no association between postepinephrine leptin and FFA levels (r = -0.14, p = 0.55). DISCUSSION: Results of this study indicate that leptin levels decrease after epinephrine administration in both lean and obese premenopausal women. However, the heterogeneity in the response of leptin to catecholamines suggests potential alterations of the leptin axis that may contribute to generate a positive energy balance and, thus, may favor weight gain in some obese individuals.

Adrenergic Agonists↗

PubMed2002

Evidence for impaired lipolysis in abdominally obese men: postprandial study of apolipoprotein B-48- and B-100-containing lipoproteins.

BACKGROUND: Abdominal obesity has been associated with postprandial hypertriglyceridemia. The contribution of intestinally and hepatically derived lipoproteins to this exaggerated postprandial lipemic response is not known. OBJECTIVE: We examined the associations between body fatness, fat distribution, and postprandial apolipoprotein (apo) B-48 and apo B-100 concentrations measured in triacylglycerol-rich lipoproteins (TRLs). DESIGN: Dietary fat tolerance was investigated in 50 men aged 28-67 y. The subjects were given a test meal containing 60 g fat/m(2) body surface area and providing 64% of energy from fat, 18% from carbohydrates, and 18% from protein. The meal provided 7524-9196 kJ, depending on body surface area. Blood samples were collected every 2 h over an 8-h period. RESULTS: The increase in plasma triacylglycerol after the meal resulted from increases in both apo B-48- and apo B-100-containing lipoproteins. The apo B-100 concentration was the strongest contributor (R(2) = 69.6%, P = 0.0001) to postprandial triacylglycerol in total TRLs; the postprandial increase in triacylglycerol was best predicted by the apo B-48 concentration (R(2) = 32.7%, P = 0.0001). Visceral abdominal fat was significantly associated with high postprandial TRL apo B-48 and apo B-100 concentrations (r = 0.30-0.44, P < 0.05). After the meal, the apo B-100 concentration in small TRLs decreased in 12 subjects. These men showed features of the insulin resistance-dyslipidemic syndrome, including more visceral fat (P = 0.07) and an altered fasting metabolic profile. CONCLUSION: A lower lipolytic capacity may contribute to the exaggerated and prolonged postprandial lipemia among abdominally obese men.

Adult↗