Little evidence of systemic and adipose tissue inflammation in overweight individuals†

Context: The effect of weight loss by diet alone or diet in conjunction with exercise on low-grade inflammation in non-obese (overweight) individuals is not known. Objective: Test the hypothesis that 24 weeks of moderate calorie restriction (CR; 25%) by diet only or with aerobic exercise would reduce markers of systemic inflammation and attenuate inflammation gene expression in subcutaneous adipose tissue. Design: Randomized controlled trial. Setting: Institutional Research Center. Participants: Thirty-five overweight (body mass index: 27.8 ± 0.7 kg/m2) but otherwise healthy participants (16M/19F) completed the study. Intervention: Participants were randomized to either CR (25% reduction in energy intake, n = 12), caloric restriction + exercise (CR + EX: 12.5% reduction in energy intake + 12.5% increase in exercise energy expenditure, n = 12), or control (healthy weight-maintenance diet, n = 11) for 6 months. Main outcome measures: Fasting serum markers of inflammation [leptin, highly sensitive C-reactive protein (hsCRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), adiponectin] and inflammation-related genes [CD68, IL-6, TNF-α, macrophage migration inhibitory factor (MIF), monocyte chemoattractant protein-1 (MCP-1), adiponectin, plasminogen activator inhibitor-1 (PAI-1)] in subcutaneous adipose tissue. Results: CR and CR + EX lost similar amounts of body weight (–10 ± 1%), fat mass (–24 ± 3%), visceral fat (–27 ± 3%), and had increased insulin sensitivity (CR: 40 ± 20%, CR + EX: 66 ± 22%). Leptin was significantly decreased from baseline (p < 0.001) in both groups however TNF-α and IL-6 were not changed. hsCRP was decreased in CR + EX. There was no change in the expression of genes involved in macrophage infiltration (CD68, MIF MCP-1, PAI-1) or inflammation (IL-6, TNF-α, adiponectin) in either CR or CR + EX. Conclusion: A 10% weight loss with a 25% CR diet alone or with exercise did not impact markers of systemic inflammation or the expression of inflammation-related adipose genes in overweight individuals

Weight gain reveals dramatic increases in skeletal muscle extracellular matrix remodeling

Context: In animal models of obesity, chronic inflammation and dysregulated extracellular matrix remodeling in adipose tissue leads to insulin resistance. Whether similar pathophysiology occurs in humans is not clear. Objective: The aim of this study was to test whether 10% weight gain induced by overfeeding triggers inflammation and extracellular matrix remodeling (gene expression, protein, histology) in skeletal muscleandsc adipose tissue in humans.Wealso investigated whether such remodelingwas associated with an impaired metabolic response (hyperinsulinemic-euglycemic clamp). Design, Setting, Participants, and Intervention: Twenty-nine free-living males were fed 40% over their baseline energy requirements for 8 weeks. Results: Ten percent body weight gain prompted dramatic up-regulation of a repertoire of extracellular matrix remodeling genes in muscle and to a lesser degree in adipose tissue. The amount of extracellular matrix genes in the muscle were directly associated with the amount of lean tissue deposited during overfeeding. Despite weight gain and impaired insulin sensitivity, there was no change in local adipose tissue or systemic inflammation, but there was a slight increase in skeletal muscle inflammation. Conclusion:Wepropose that skeletal muscle extracellular matrix remodeling is another feature of the pathogenic milieu associated with energy excess and obesity, which, if disrupted, may contribute to the development of metabolic dysfunction. © 2014 by the Endocrine Society

Physiological relevance of aerobic exercise training for the preparation of bariatric surgery candidates

Bariatric surgery is popular among clinicians to treat obesity because of its high impact on body weight reduction. However, the fast rate of weight loss has several consequences, such as loss of muscle mass and strength, and functional capacity. Therefore, preoperative interventions are needed to secure the surgery’s success, where physical exercise could be an effective intervention. Nevertheless, the most effective preoperative exercise prescription, along with its potential post-surgical carry-over effects, is still unclear. Recent studies have highlighted that exercise programs that differ, for instance, in intensity, induce differential metabolic benefits, that seem to be tissue-specific. This might be clinically relevant since it has been described that obesity-related metabolic impairments are not stereotypical in humans. This brief review analyses some tissue-specific disturbances derived from obesity, and how aerobic exercise programs, particularly high-intensity interval training and moderate-intensity constant training could elicit differential benefits, particularly in candidates to undergo bariatric surgery.La cirugía bariátrica es popular para el tratamiento de la obesidad debido a su alto impacto sobre la reducción del peso corporal. Sin embargo, esta acelerada pérdida de peso tiene variadas consecuencias, tales como el descenso de masa y fuerza muscular, así como de la capacidad funcional. Por tanto, el manejo preoperatorio es necesario para asegurar el éxito quirúrgico, dentro de las cuales el ejercicio físico ocupa un lugar importante. No obstante, se desconoce la prescripción del ejercicio más efectiva en esta población, así como los potenciales efectos que puedan perdurar posterior a la cirugía. Estudios recientes destacan que programas de ejercicio que difieren, por ejemplo, en intensidad, inducen beneficios metabólicos diferenciales, los cuales parecer ser tejido-dependientes. Esto puede ser clínicamente relevante, considerando que las alteraciones metabólicas asociadas a obesidad no son estereotípicas en humanos. Esta breve revisión analiza algunas alteraciones derivadas de obesidad, las cuales se presentan de forma específica en diferentes tejidos, y además como diferentes programas de ejercicio aeróbico, tales como el interválico de alta intensidad como el de intensidad moderada y constante podrían provocar beneficios diferenciales, particularmente en candidatos a cirugía bariátrica.Sociedad Argentina de Fisiologí

Constant-Moderate and High-Intensity Interval Training Have Differential Benefits on Insulin Sensitive Tissues in High-Fat Fed Mice

In a mouse model of diet-induced obesity, this study determined if two exercise prescriptions with equivalent time and distance covered, [constant-moderate endurance (END) and high intensity interval training (HIIT)], exert differential metabolic benefits on insulin sensitive tissues. Male 10 week old C57BL/6 mice were fed a high fat diet (HFD; 45% kcal fat) ad libitum for 10 weeks and for a further 10 weeks they underwent END or HIIT training (3 × 40 min sessions/wk). Untrained HFD and chow-fed mice acted as controls. At 30 weeks of age, mice were sacrificed and quadriceps muscle, subcutaneous adipose tissue (SAT) and liver were excised. Neither END nor HIIT altered body weight or composition in HFD mice. In quadriceps, HFD decreased high-molecular weight adiponectin protein, which was normalized by END and HIIT. In contrast, HIIT but not END reversed the HFD-driven decrease in the adiponectin receptor 1 (AdipoR1). In SAT, both programs tended to decrease collagen VI protein (p = 0.07–0.08) in HFD, whereas only HIIT induced an increase in the mRNA (3-fold vs. HFD untrained) and protein (2-fold vs. HFD untrained) of UCP1. In liver, only END reversed collagen I accumulation seen in HFD untrained mice. Our results suggest that HIIT may promote better systemic metabolic changes, compared to END, which may be the result of the normalization of muscle AdipoR1 and increased UCP1 seen in SAT. However, END was more effective in normalizing liver changes, suggesting differential metabolic effects of END and HIIT in different tissues during obesity

Higher circulating leukocytes in women with PCOS is reversed by aerobic exercise

Polycystic ovary syndrome (PCOS) is characterized by insulin resistance, elevated circulating leukocytes, and hypothesized to have higher adipose tissue inflammation. Aerobic exercise reduces circulating leukocytes and improves insulin sensitivity in obese individuals, but the effect of exercise on inflammation in PCOS is not known. We investigated circulating leukocytes, insulin sensitivity by euglycemic-hyperinsulinemic clamp, serum pro- and anti-inflammatory markers (hsCRP, TNF-α, total and high molecular weight adiponectin), and abdominal subcutaneous adipose tissue (SAT) gene expression of proinflammatory markers in 8 PCOS women and 8 obese control females matched for BMI. Additionally, in a prospective study, the 8 women with PCOS underwent a 16-week aerobic exercise regimen with the same measures performed post-intervention. Compared to controls, white blood cell counts (WBC) were 30% higher (p = 0.04) and circulating total adiponectin levels were 150% lower (p = 0.03) in women with PCOS at baseline/pre-exercise conditions. SAT gene expression of macrophage migration inhibitory factor (MIF, p \u3c 0.01) and interleukin-6 (IL-6, p \u3c 0.05) were also lower in women with PCOS. In response to 16 weeks of aerobic exercise, insulin sensitivity improved (p \u3c 0.01) and WBC counts decreased (p = 0.02). The exercise-induced change in WBC and circulating neutrophils correlated inversely with changes in glucose disposal rate (r = -0.73, p = 0.03; and r = -0.82, p = 0.01, respectively). Aerobic exercise reduced serum leptin (p \u3c 0.05) after 4 weeks, trended to reduce the ratio of leptin-to-high molecular weight adiponectin (p \u3c 0.1) by the 8th week, and significantly increased serum dehydroepiandrosterone sulfate (DHEA-S, p \u3c 0.001) after 16 weeks. In conclusion, women with PCOS have higher circulating leukocytes compared to controls, which can be reversed by aerobic exercise and is associated with improvements in insulin sensitivity

Energy adaptations persist 2 years after sleeve gastrectomy and gastric bypass

Non-surgical weight loss induces a greater than expected decrease in energy expenditure, a phenomenon known as \u27metabolic adaptation\u27. The effects of different bariatric surgery procedures on metabolic adaptation are not yet known and may partially contribute to weight loss success. We compared resting energy expenditure (REE) in 35 subjects (nine males; age = 46 ± 11 years; BMI = 42.1 ± 6.5 kg/m2) undergoing gastric band, sleeve gastrectomy or Roux-en-Y gastric bypass (RYGB) up to 2 years after surgery. We found a greater than expected reduction of 130-300 kcal/day at 6 weeks after sleeve and bypass surgery which was not explained by changes in body composition; this change was not seen in the band group. The suppression in REE after sleeve and RYGB remained up to 2 years, even after weight loss had plateaued. Our findings suggest that energy adaptation is not a contributing mechanism to medium-term weight maintenance after sleeve and RYGB bariatric surgeries

No effect of caloric restriction on salivary cortisol levels in overweight men and women

OBJECTIVE: The effect of weight loss by diet or diet and exercise on salivary cortisol levels, a measure of hypothalamic pituitary adrenal activity, in overweight individuals is not known. The objective was to test the hypothesis that 24 weeks of moderate caloric restriction (CR) (25%) by diet or diet and aerobic exercise would alter morning and diurnal salivary cortisol levels. DESIGN AND SETTING: Randomized control trial in an institutional research center. PARTICIPANTS: Thirty-five overweight (BMI: 27.8±0.7 kg/m(2)) but otherwise healthy participants (16 M/19 F). INTERVENTION: Participants were randomized to either calorie restriction (CR: 25% reduction in energy intake, n=12), calorie restriction+exercise (CR+EX: 12.5% reduction in energy intake+12.5% increase in exercise energy expenditure, n=12) or control (healthy weight-maintenance diet, n=11) for 6 months. MAIN OUTCOME MEASURE: Salivary cortisol measured at 8:00, 8:30, 11:00, 11:30, 12:30, 13:00, 16:00 and 16:30. Morning cortisol was defined as the mean cortisol concentration at 08:00 and 08:30. Diurnal cortisol was calculated as the mean of the 8 cortisol measures across the day. RESULTS: In the whole cohort, higher morning and diurnal cortisol levels were associated with impaired insulin sensitivity (morning: P=0.004, r(2)=0.24; diurnal: P=0.02, r(2)=0.15). Using mixed model analysis, there was no significant effect of group, time or sex on morning or diurnal cortisol levels. CONCLUSION: A 10% weight loss with a 25% CR diet alone or with exercise did not impact morning or diurnal salivary cortisol levels