Biomedical subjects

Marie-Agnès Arnal

Publications and source records attributed to Marie-Agnès Arnal.

3 recordsLinked to original sources

PubMed2004

Isomers of conjugated linoleic acid decrease plasma lipids and stimulate adipose tissue lipogenesis without changing adipose weight in post-prandial adult sedentary or trained Wistar rat.

The respective effects and interactions of supplementation with two conjugated linoleic acid (CLA) isomers and exercise on plasma metabolic profile, activity of lipogenic enzymes and cellularity in two adipose tissue sites, those of the liver and heart, were examined in adult Wistar rats. Rats that were either sedentary or exercise-trained by treadmill running were fed one of four diets: a diet without CLA; a diet with either 1% cis 9, trans 11 CLA or 1% trans 10, cis 12 CLA; or a mixture of both isomers (1% of each) for 6 weeks. We observed that the exercise decreased lipogenic enzyme activities in epididymal and perirenal adipose tissue. Plasma cholesterol, insulin, and leptin concentrations were lower in exercise-trained rats than in sedentary rats. The ingestion of either CLA mixture or the trans 10, cis 12 CLA increased lipogenic enzyme activities in epididymal tissue and more markedly in perirenal adipose tissue, especially in sedentary rats, and without affecting adipose tissue weight or cellularity. A similar effect of trans 10, cis 12 CLA was observed in regard to malic enzyme activity in the liver. In addition, this isomer decreased plasma lipid and urea concentrations and increased plasma 3-hydroxybutyrate levels. The ingestion of cis 9, trans 11 CLA increased fatty acid synthase activity in perirenal adipose tissue in sedentary rats and decreased plasma cholesterol and leptin concentrations. These results show that isomers of CLA decrease plasma lipids and stimulate adipose tissue lipogenesis without changing adipose weight in adult sedentary or exercise-trained rat, thus suggesting a stimulation of adipose tissue turnover.

Adipose Tissue↗

PubMed2004

Effects of two conjugated linoleic Acid isomers on body fat mass in overweight humans.

OBJECTIVE: To examine the effects of two different conjugated linoleic acid (CLA) isomers at two different intakes on body composition in overweight humans. RESEARCH METHODS AND PROCEDURES: Eighty-one middle-aged, overweight, healthy men and women participated in this bicentric, placebo-controlled, double-blind, randomized study. For 6 weeks (run-in period), all subjects consumed daily a drinkable dairy product containing 3 g of high oleic acid sunflower oil. Volunteers were then randomized over five groups receiving daily either 3 g of high oleic acid sunflower oil, 1.5 g of cis-9,trans-11 (c9t11) CLA, 3 g of c9t11 CLA, 1.5 g of trans-10,cis-12 (t10c12) CLA, or 3 g of t10c12 CLA administrated as triacylglycerol in a drinkable dairy product for 18 weeks. Percentage body fat mass and fat and lean body mass were assessed at the end of the run-in and experimental periods by DXA. Dietary intake was also recorded. RESULTS: Body fat mass changes averaged 0.1 +/- 0.9 kg (mean +/- SD) in the placebo group and -0.3 +/- 1.4, -0.8 +/- 2.1, 0.0 +/- 2.3, and -0.9 +/- 1.7 kg in the 1.5-g c9t11, 3-g c9t11, 1.5-g t10c12, and 3-g t10c12 groups, respectively. Changes among the groups were not significantly different (p = 0.444). Also, lean body mass and dietary intake were not significantly different among the treatments. DISCUSSION: A daily consumption of a drinkable dairy product containing up to 3 g of CLA isomers for 18 weeks had no statistically significant effect on body composition in overweight, middle-aged men and women.

Adipose Tissue↗

PubMed2002

Pulse protein feeding pattern restores stimulation of muscle protein synthesis during the feeding period in old rats.

Muscle loss during aging could be related to a lower sensitivity of muscle protein synthesis to feeding. To overcome this decrease without increasing protein intake, we proposed to modulate the daily protein feeding pattern. We showed that consuming 80% of dietary proteins at noon (pulse pattern) improved nitrogen balance in elderly women. The present study was undertaken in rats to determine which tissues are the targets of the pulse pattern and what mechanisms are involved. Male Sprague-Dawley 11- and 23-mo-old rats (n = 32 per age) were fed 4 isoproteic (18% protein) meals/d for 10 d. Then half of the rats at each age were switched to a 11/66/11/11% repartition of daily proteins (pulse pattern) for 21 d. On d 21, rats were injected with a flooding dose of L-(13)C-valine (50 atom% excess, 150 micromol/100 g body) and protein synthesis rates were measured in liver, small intestine and gastrocnemius muscle in either the postabsorptive or the fed state. Epitrochlearis muscle degradation rates and plasma amino acid concentrations were measured at the same times. The pulse pattern had the following effects: 1) it significantly increased liver protein synthesis response to feeding and postprandial plasma amino acid concentrations at both ages; 2) it restored a significant response to feeding of gastrocnemius muscle protein synthesis in old rats; and 3) it had no effect in small intestine or on muscle breakdown. Thus, using a pulse pattern could be useful in preventing the age-related loss of muscle by increasing feeding-induced stimulation of muscle protein synthesis.

Aging↗