Exercise training markedly augments dietary weight loss-induced improvements in multi-organ system metabolic function in people with obesity and prediabetes
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ABSTRACT: The additional therapeutic effects of regular exercise during a dietary weight loss program in people with obesity and prediabetes are unclear. We evaluated the effect of 10% weight loss, induced within ~5 months by calorie-restriction alone (Diet-ONLY, n=8) or calorie-restriction plus multi-modal exercise training (Diet+EX, n=8), on metabolic function in people with obesity and prediabetes. Whole-body (primarily muscle) and hepatic insulin sensitivity were 2-3 fold greater in the Diet+EX than the Diet-ONLY group, and were accompanied by increased muscle expression of genes involved in mitochondrial biogenesis, energy metabolism and angiogenesis in the Diet+EX group without any change in the Diet-ONLY group. There were no differences between groups in plasma branched-chain amino acids or markers of inflammation, and both interventions caused similar changes in the gut microbiome. These results demonstrate that adding regular exercise to a diet-induced weight loss program has profound metabolic benefits in people with obesity and prediabetes.
Project description:It has been proposed that there is a direct pathophysiological link between metabolic dysfunction and musculoskeletal degeneration in people with obesity but direct evidence for this proposition is lacking. We performed a comprehensive assessment of musculoskeletal status in people with obesity and prediabetes and a control group of sex-, age- and adiposity-matched participants with normoglycemia. We find muscle mass and bone mineral density scores, muscle growth markers, myofiber size, myofiber capillarization, and muscle type 2 macrophage content are lower, and intramyocellular lipid, but not inter- or intra-muscular adipose tissue, content are higher in people with prediabetes compared with the control group. Moreover, muscle strength during repeated maximum voluntary contractions declines faster in people with prediabetes. These findings demonstrate a close interrelationship between metabolic and musculoskeletal dysfunction in people with obesity and have direct clinical implications, because greater muscle fatigability in people with prediabetes may present a barrier to physical activity.
Project description:We performed a factorial experiment examining the effects of calorie restriction (CR) and exercise (EX) in mice. CR mice received 70% of calories but 100% of all other nutrients compared to AL mice. Food consumption, weight gain, and physical activity levels were recorded for 6 weeks. Diet and exercise treatments, both alone and in combination, had significant effects on body composition and levels of physical activity. Affymetrix oligo microarrays were used to determine global gene expression patterns in mammary gland total RNA. CR and EX had some overlapping but primarily unique effects on mammary gene expression, with CR affecting a much larger number of genes. The gene changes presented suggest that CR and EX influence mammary gland development and potentially carcinogenesis through distinct pathways. Keywords: 2 X 2 factorial mouse experiment; ad lib; calorie restriction; exercise; exercise + calorie restriction. Endpoints: body composition; bone density; gene expression in mammary gland
Project description:Calorie-rich foods, particularly those high in fat and sugar, evoke pleasure in both humans and animals. However, prolonged consumption of such foods may reduce their hedonic value, potentially contributing to obesity. Here, we investigated this phenomenon in mice on a chronic high-fat diet (HFD). While these mice preferred high-fat food over regular chow in their home cages, they showed reduced interest in calorie-rich foods in a no-effort setting. This paradoxical decrease in hedonic feeding has been reported previously, but its neurobiological basis remains unclear. We found that in regular diet mice, neurons in the lateral nucleus accumbens projecting to the ventral tegmental area (NAcLat→VTA) encoded hedonic feeding behaviors. In HFD mice, this behavior was reduced and uncoupled from neural activity. Optogenetic stimulation of the NAcLat→VTA pathway increased hedonic feeding in regular diet mice but not in HFD mice, though this behavior was restored when HFD mice returned to a regular diet. HFD mice exhibited reduced neurotensin expression and release in the NAcLat→VTA pathway. Furthermore, neurotensin knockout in the NAcLat and neurotensin receptor blockade in the VTA each abolished optogenetic-induced hedonic feeding behavior. Enhancing neurotensin signaling via overexpression normalized aspects of diet-induced obesity, including weight gain and hedonic feeding. Altogether, our findings identify a neural circuit mechanism linking the devaluation of hedonic foods with obesity.
Project description:In utero undernutrition is associated with obesity and insulin resistance, although its effect on skeletal muscle remains poorly defined. We report that, in mice, adult offspring from undernourished dams have decreased energy expenditure, decreased skeletal muscle mitochondrial content, and altered energetics in isolated mitochondria and permeabilized muscle fibers. Strikingly, when these mice are put on a 40% calorie restricted diet they lose half as much weight as calorie restricted controls. Our results reveal for the first time that in utero undernutrition alters metabolic physiology having a profound effect on skeletal muscle energetics and response to calorie restriction in adulthood. We have used a mouse model of low birth weight generated through 50% food restriction of mouse dams during the third week of gestation. We have studied in utero food restricted offspring and control offspring that were not food restricted in utero in both the ad libitum and calorie restricted states. Gene expression profiling was performed on tibialis anterior muscle from 8 mice per group, pooled in pairs.
Project description:Dietary interventions are effective ways to extend or shorten lifespan. By examining midlife hepatic gene expressions in mice under different dietary conditions, which resulted in different lifespans and aging-related phenotypes, we were able to identify genes and pathways that modulate the aging process. We found that pathways transcriptionally correlated with diet-modulated lifespan and physiological changes were enriched for lifespan-modifying genes. Male C57BL/6J mice at 4 weeks of age were purchased from Shanghai Animal Co, Ltd. Mice were maintained under a 12-hour dark/light cycle (lights on at 6:30 am) at a temperature of 22 ± 3 °C in accredited animal facilities. Prior to the start of experiment, mice were maintained on a low-fat diet (Research Diets Inc., New Brunswick, NJ) for one week. At the age of 5 weeks, animals were randomly assigned to one of the 6 intervention groups (n = 30 for each group): feeding of a low-fat diet (10% fat, D12450B, Research Diets) ad libitum (LF) or with 30% calorie restriction (LF+CR) or with voluntary running exercise (LF+Ex), feeding of a high-fat diet (60% fat, D12492, Research Diets) ad libitum (HF) or with 30% calorie restriction (HF+CR) or with voluntary running exercise (HF+Ex). All mice were housed individually during the study. The daily consumption of food in LF and HF groups was recorded over a week and averaged to determine the amount of food for the following week for the LF+CR and HF+CR groups, respectively. After 1 week acclimation in cage with the locked running wheels, mice in the LF+Ex and HF+Ex groups were allowed free access to a running wheel, and the running distance and time were recorded automatically by the equipment. The hepatic transcriptional level for 3 mice from each intervention group at 62 weeks of age was analyzed using Affymetrix Mouse Genome 430 2.0 Arrays.
Project description:Obese rats were calorically restricted with (EX) or without (SED) treadmill exercise (1 h/day, 6 days/wk, 15 m/min) to induce and maintain weight loss. After 6 weeks of WLM, subsets of WLM-SED and WLM-EX rats were allowed ad libitum access to food for 1 day to promote relapse (REL). An energy gap-matched group of sedentary, relapsing rats (REL-GM) were provided a diet matched to the positive energy imbalance of the REL-EX rats.
Project description:Lean male mice were fed a high fat diet (HFD, lard 24% w/w) for 16 weeks. At 9 weeks, when all hallmarks of prediabetes were established, groups of mice were treated with drug (rosiglitazone, pioglitazone, T0901317, or salicylate) for another 7 weeks together with the high fat diet. An additional group was switched back to a chow diet (dietary lifestyle intervention) after the first 9 weeks of high fat diet. All groups were compared to a control group receiving HFD alone and to a reference group fed chow (baseline reference) for the entire experimental period (16 weeks). One group (n=9) remained on maintenance chow throughout the entire study period (16 weeks) and served as healthy, age-matched control. After the nine week run-in period, the HFD fed mice were matched into thirteen groups based on body weight. The first group (n=9) was sacrificed immediately after matching. The second group (n=15) was continued on HFD until the end of the experiment at t=16 weeks. The fourth group (n=9) was switched to regular chow (dietary lifestyle intervention). The other groups (each n=9) continued on HFD supplemented with drugs typically used in clinical practice. More specifically, following drugs were mixed into HFD ; rosiglitazone (0.010% w/w), pioglitazone (0.010% w/w), T0901317 (0.010% w/w) and salicylate (0.40% w/w).
Project description:Background. Differential gene expression in adipose tissue during diet-induced weight loss followed by a weight stability period is not well characterized. Markers of these processes may provide a deeper understanding of the underlying mechanisms. Objective. To identify differentially expressed genes in human adipose tissue during weight loss and weight maintenance after weight loss. Design. RNA from subcutaneous abdominal adipose tissue from nine obese subjects was obtained and analyzed at baseline, after weight reduction on a low calorie diet (LCD), and after a period of group therapy in order to maintain weight stability. Results. Subjects lost 18.8 + 5.4% of their body weight during the LCD and maintained this weight during group therapy. Insulin sensitivity (HOMA) improved after weight loss with no further improvement during weight maintenance. Cyclin-dependent kinase inhibitor 2B (CDKN2B) and JAZF zinc finger 1 (JAZF1), associated with type 2 diabetes, were downregulated. We could also confirm the downregulation of candidates for obesity and related traits, such as tenomodulin (TNMD) and matrix metallopeptidase 9 (MMP9), with weight loss. The expression of other candidates, such as cell death-inducing DFFA-like effector A (CIDEA) and stearoyl-CoA desaturase (SCD) were upregulated during weight loss but returned to baseline levels during weight maintenance. Conclusion. Genes in the adipose tissue are differentially expressed during weight loss and weight maintenance after weight loss. Genes that show sustained regulation may be of potential interest as markers of the beneficial effects of weight loss whereas others seem to be primarily involved in the process of weight loss itself. Nine participants were prescribed a low calorie diet (LCD) containing 1200 kcal/day for approximately three months (101 ± 26 days). Following the weight reduction phase the participants attended a six month follow-up period (167 ± 37 days). By protocol design, subjects were eligible to enter the study if they had lost at least 10% of their initial body weight during the LCD-period and maintained this weight (+5%) after group therapy. Subcutaneous adipose tissue samples were obtained at three time-points: (i) at baseline, (ii) after weight reduction when subjects were no longer losing weight, and (iii) after the group therapy weight maintenance phase.
Project description:To study how exercise induces bone remodeling in diet-induced obesity in a comprehensive way.8-week male C57/B6 mice were fed with HFD to establish an obese mice model. Then mice were randomly divided into 2 groups: the exercise and the control groups. The exercise group of mice was put on a moderate-intensity treadmill running for 12 weeks.We employed unbiased RNA-Seq to comprehensively investigate the exercise effect on the bone marrow of diet-induced obesity mice in vivo.