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Dietary fat may modulate adipose tissue homeostasis through the processes of autophagy and apoptosis.
Camargo, A, Rangel-Zúñiga, OA, Alcalá-Díaz, J, Gomez-Delgado, F, Delgado-Lista, J, García-Carpintero, S, Marín, C, Almadén, Y, Yubero-Serrano, EM, López-Moreno, J, et al
European journal of nutrition. 2017;(4):1621-1628
Abstract
PURPOSE Obesity increases the risk of cardiovascular disease, type 2 diabetes mellitus and cancer development. Autophagy and apoptosis are critical processes for development and homeostasis in multicellular organisms and have been linked to a variety of disorders. We aimed to investigate whether the quantity and quality of dietary fat can influence these processes in the adipose tissue of obese people. METHODS A randomized, controlled trial within the LIPGENE study assigned 39 obese people with metabolic syndrome to 1 of 4 diets: (a) a high-saturated fatty acid diet, (b) a high-monounsaturated fatty acid (HMUFA) diet, and (c, d) two low-fat, high-complex carbohydrate diets supplemented with long-chain n-3 polyunsaturated fatty acids (LFHCC n-3) or placebo (LFHCC), for 12 weeks each. RESULTS We found an increase in the expression of autophagy-related BECN1 and ATG7 genes after the long-term consumption of the HMUFA diet (p = 0.001 and p = 0.004, respectively) and an increase in the expression of the apoptosis-related CASP3 gene after the long-term consumption of the LFHCC and LFHCC n-3 diets (p = 0.001 and p = 0.029, respectively). CASP3 and CASP7 gene expression changes correlated with HOMA index. CONCLUSION Our results suggest that the processes of autophagy and apoptosis in adipose tissue may be modified by diet and that the consumption of a diet rich in monounsaturated fat may contribute to adipose tissue homeostasis by increasing autophagy. They also reinforce the notion that apoptosis in adipose tissue is linked to insulin resistance. CLINICAL TRIAL REGISTRATION NUMBER ClinicalTrials.gov NCT00429195.
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Transcriptomic coordination in the human metabolic network reveals links between n-3 fat intake, adipose tissue gene expression and metabolic health.
Morine, MJ, Tierney, AC, van Ommen, B, Daniel, H, Toomey, S, Gjelstad, IM, Gormley, IC, Pérez-Martinez, P, Drevon, CA, López-Miranda, J, et al
PLoS computational biology. 2011;(11):e1002223
Abstract
Understanding the molecular link between diet and health is a key goal in nutritional systems biology. As an alternative to pathway analysis, we have developed a joint multivariate and network-based approach to analysis of a dataset of habitual dietary records, adipose tissue transcriptomics and comprehensive plasma marker profiles from human volunteers with the Metabolic Syndrome. With this approach we identified prominent co-expressed sub-networks in the global metabolic network, which showed correlated expression with habitual n-3 PUFA intake and urinary levels of the oxidative stress marker 8-iso-PGF(2α). These sub-networks illustrated inherent cross-talk between distinct metabolic pathways, such as between triglyceride metabolism and production of lipid signalling molecules. In a parallel promoter analysis, we identified several adipogenic transcription factors as potential transcriptional regulators associated with habitual n-3 PUFA intake. Our results illustrate advantages of network-based analysis, and generate novel hypotheses on the transcriptomic link between habitual n-3 PUFA intake, adipose tissue function and oxidative stress.
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The effects of exercise training on abdominal visceral fat, body composition, and indicators of the metabolic syndrome in postmenopausal women with and without estrogen replacement therapy: the HERITAGE family study.
Green, JS, Stanforth, PR, Rankinen, T, Leon, AS, Rao Dc, Dc, Skinner, JS, Bouchard, C, Wilmore, JH
Metabolism: clinical and experimental. 2004;(9):1192-6
Abstract
The purpose of this research was to investigate the effects of apriori estrogen replacement therapy (ERT) and endurance exercise training in postmenopausal women on abdominal visceral fat (AFV) and other selected variables related to body composition and the metabolic syndrome (MS). Forty-eight healthy and previously sedentary postmenopausal women (mean age, 54.3 years) who were enrolled in the HERITAGE Family Study (HFS) served as subjects. Of these 48 women, 18 were currently taking ERT and the remaining 30 were taking no supplemental estrogen (NHRT). Computed tomography (CT) scans were used to assess AVF as well as total abdominal fat (TAF) and abdominal subcutaneous fat (ASF). Body mass index (BMI) and waist-to-hip ratios (WHR) were calculated while body fat percentage (%FAT) and total fat mass (FATM) was assessed using underwater weighing. Blood assays for HDL-cholesterol (HDL-C), LDL-cholesterol (LDL-C), and triglycerides (TG) were conducted at a Centers for Disease Control (CDC) certified laboratory, while blood pressure measurements were assessed using an automated system. All measurements were obtained in duplicate before and after a regimen of endurance exercise training. Analysis of variance (ANOVA) showed AVF to be an average of 31.6 cm(2) less in the women receiving ERT, but lost statistical significance when AVF was adjusted for FATM. Mean values for TAF, ASF, and waist girth were also less in the women receiving ERT, but only waist girth achieved statistical significance. No differences were found in BMI or %FAT, but mean WHR was 5% smaller in the ERT group. Baseline values for HDL-C was higher and LDL-C lower in the ERT group. Prevalence of the MS tended to be greater in the NHRT group, but did not achieve statistical significance. There were no differences in training responses in any of the body composition variables between groups, however, in the ERT group LDL-C decreased with training while TG increased. It was concluded that postmenopausal women taking ERT tended to have lower values of AVF and other indicators of body composition, a more favorable lipid profile, and a slightly reduced risk of the MS when compared with women not taking supplemental hormones. Also exercise training did not improve the overall MS status of either group, as LDL-C status improved in the ERT group while TG decreased in the NHRT group.
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Changes in abdominal subcutaneous fat water content with rapid weight loss and long-term weight maintenance in abdominally obese men and women.
Laaksonen, DE, Nuutinen, J, Lahtinen, T, Rissanen, A, Niskanen, LK
International journal of obesity and related metabolic disorders : journal of the International Association for the Study of Obesity. 2003;(6):677-83
Abstract
OBJECTIVE Insulin resistance decreases blood flow and volume in fat tissue. We hypothesised that fat tissue nutritive blood flow and volume, and thereby water content, would increase during weight loss and weight maintenance in obese persons. DESIGN Longitudinal clinical intervention with a 9-week very-low-calorie diet (VLCD) followed by one year of weight maintenance. SUBJECTS Obese men (n=13) and women (n=14) with the metabolic syndrome. MEASUREMENTS Water content of abdominal subcutaneous fat tissue as estimated by a sensor on the skin surface measuring the dielectric constant at 300 MHz. Anthropometric measures of fatness and fat distribution. Biochemical measures related to insulin resistance. RESULTS Subjects lost 14.5+/-3.4% of body weight during the VLCD, and generally sustained this weight loss during weight maintenance. Insulin sensitivity as estimated by an index (qualitative insulin sensitivity check index) increased during the VLCD, and remained increased throughout weight maintenance. The dielectric constant increased from 23.3+/-2.3 to 25.0+/-2.1 (P<0.001) during the VLCD, and further to 27.8+/-1.9 (P<0.001) during weight maintenance, indicating an increase in the water content of subcutaneous fat. The increase in subcutaneous fat water content did not correlate with weight loss and other measures of adiposity during the VLCD, but there was an inverse correlation that strengthened in significance from baseline to 6, 9 and 12 mo (r=-0.32 to -0.64, P=0.079-0.002). Increases in subcutaneous fat water content also correlated with improvements in insulin sensitivity at 6, 9 and 12 months of weight maintenance (r=0.34-0.54, P=0.094-0.006). CONCLUSIONS Water content of abdominal subcutaneous adipose tissue increases with weight loss in obese persons with the metabolic syndrome, and may reflect increased subcutaneous fat tissue nutritive blood flow. The increase in water content correlates with the increase in insulin sensitivity, suggesting that weight loss and consequent improved insulin sensitivity could mediate the increase in abdominal subcutaneous fat hydration.