scholarly journals Macrophage Content in Subcutaneous Adipose Tissue: Associations With Adiposity, Age, Inflammatory Markers, and Whole-Body Insulin Action in Healthy Pima Indians

Diabetes ◽  
2008 ◽  
Vol 58 (2) ◽  
pp. 385-393 ◽  
Author(s):  
E. Ortega Martinez de Victoria ◽  
X. Xu ◽  
J. Koska ◽  
A. M. Francisco ◽  
M. Scalise ◽  
...  
2009 ◽  
Vol 297 (5) ◽  
pp. E999-E1003 ◽  
Author(s):  
Birgit Gustafson ◽  
Silvia Gogg ◽  
Shahram Hedjazifar ◽  
Lachmi Jenndahl ◽  
Ann Hammarstedt ◽  
...  

Obesity is associated mainly with adipose cell enlargement in adult man (hypertrophic obesity), whereas the formation of new fat cells (hyperplastic obesity) predominates in the prepubertal age. Adipose cell size, independent of body mass index, is negatively correlated with whole body insulin sensitivity. Here, we review recent findings linking hypertrophic obesity with inflammation and a dysregulated adipose tissue, including local cellular insulin resistance with reduced IRS-1 and GLUT4 protein content. In addition, the number of preadipocytes in the abdominal subcutaneous adipose tissue capable of undergoing differentiation to adipose cells is reduced in hypertrophic obesity. This is likely to promote ectopic lipid accumulation, a well-known finding in these individuals and one that promotes insulin resistance and cardiometabolic risk. We also review recent results showing that TNFα, but not MCP-1, resistin, or IL-6, completely prevents normal adipogenesis in preadipocytes, activates Wnt signaling, and induces a macrophage-like phenotype in the preadipocytes. In fact, activated preadipocytes, rather than macrophages, may completely account for the increased release of chemokines and cytokines by the adipose tissue in obesity. Understanding the molecular mechanisms for the impaired preadipocyte differentiation in the subcutaneous adipose tissue in hypertrophic obesity is a priority since it may lead to new ways of treating obesity and its associated metabolic complications.


1992 ◽  
Vol 263 (5) ◽  
pp. E850-E855 ◽  
Author(s):  
L. Simonsen ◽  
J. Bulow ◽  
J. Madsen ◽  
N. J. Christensen

Whole body energy expenditure, thermogenic and metabolic changes in the forearm, and intercellular glucose concentrations in subcutaneous adipose tissue on the abdomen determined by microdialysis were measured during epinephrine infusion in healthy subjects. After a control period, epinephrine was infused at rates of 0.2 and 0.4 nmol.kg-1 x min-1. Whole body resting energy expenditure was 4.36 +/- 0.56 (SD) kJ/min. Energy expenditure increased to 5.14 +/- 0.74 and 5.46 +/- 0.79 kJ/min, respectively (P < 0.001), during the epinephrine infusions. Respiratory exchange ratio was 0.80 +/- 0.04 in the resting state and did not change. Local forearm oxygen uptake was 3.9 +/- 1.3 mumol.100 g-1 x min-1 in the basal period. During epinephrine infusion, it increased to 5.8 +/- 2.1 (P < 0.03) and 7.5 +/- 2.3 mumol.100 g-1 x min-1 (P < 0.001). Local forearm glucose uptake was 0.160 +/- 0.105 mumol.100 g-1 x min-1 and increased to 0.586 +/- 0.445 and 0.760 +/- 0.534 mumol.100 g-1 x min-1 (P < 0.025). The intercellular glucose concentration in the subcutaneous adipose tissue on the abdomen was equal to the arterial concentration in the basal period but did not increase as much during infusion of epinephrine, indicating glucose uptake in adipose tissue in this condition. If it is assumed that forearm skeletal muscle is representative for the average skeletal muscle, it can be calculated that on average 40% of the enhanced whole body oxygen uptake induced by infusion of epinephrine is taking place in skeletal muscle. It is proposed that adipose tissue may contribute to epinephrine-induced thermogenesis.


2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Engin Baturcam ◽  
Jehad Abubaker ◽  
Ali Tiss ◽  
Mohamed Abu-Farha ◽  
Abdelkrim Khadir ◽  
...  

RANTES and its CCR5 receptor trigger inflammation and its progression to insulin resistance in obese. In the present study, we investigated for the first time the effect of physical exercise on the expression of RANTES and CCR5 in obese humans. Fifty-seven adult nondiabetic subjects (17 lean and 40 obese) were enrolled in a 3-month supervised physical exercise. RANTES and CCR5 expressions were measured in PBMCs and subcutaneous adipose tissue before and after exercise. Circulating plasma levels of RANTES were also investigated. There was a significant increase in RANTES and CCR5 expression in the subcutaneous adipose tissue of obese compared to lean. In PBMCs, however, while the levels of RANTES mRNA and protein were comparable between both groups, CCR5 mRNA was downregulated in obese subjects (P<0.05). Physical exercise significantly reduced the expression of both RANTES and CCR5 (P<0.05) in the adipose tissue of obese individuals with a concomitant decrease in the levels of the inflammatory markers TNF-α, IL-6, and P-JNK. Circulating RANTES correlated negatively with anti-inflammatory IL-1ra (P=0.001) and positively with proinflammatory IP-10 and TBARS levels (P<0.05). Therefore, physical exercise may provide an effective approach for combating the deleterious effects associated with obesity through RANTES signaling in the adipose tissue.


1994 ◽  
Vol 266 (1) ◽  
pp. E151-E154 ◽  
Author(s):  
T. J. Kowalski ◽  
M. Watford

Information about adipose tissue amino acid metabolism is limited, with most data derived from studies in vitro. The purpose of this study was to further characterize the role of adipose tissue in glutamine metabolism in the rat in vivo. The extracellular concentrations of glutamine, glutamate, alanine, and ammonia were measured in the rat inguinal fat pad using a microdialysis sampling technique. A calibration method was used to accurately assess the extracellular levels of metabolites, and a comparison of these concentrations with those in arterial blood allowed determination of the net flux of each compound. The adipose tissue-arterial blood concentration differences were 122 +/- 19, 54 +/- 37, -61 +/- 21, and -28 +/- 13 microM for glutamine, alanine, glutamate, and ammonia, respectively, indicating a production of glutamine and an uptake of glutamate by subcutaneous adipose tissue. The magnitude of glutamine production suggests that adipose tissue may play a significant role in whole body glutamine homeostasis.


2012 ◽  
Vol 167 (4) ◽  
pp. 543-551 ◽  
Author(s):  
Lars Christian Gormsen ◽  
Christian Høst ◽  
Britta Eilersen Hjerrild ◽  
Steen Bønløkke Pedersen ◽  
Søren Nielsen ◽  
...  

ContextEstradiol (E2) promotes and maintains the female phenotype characterized by subcutaneous fat accumulation. There is evidence to suggest that this effect is due to increased anti-lipolytic α2A-adrenergic receptors, but whether this requires long-term exposure to E2or is an immediate effect is not clear.ObjectiveTo study acute effects of a single dose (4 mg) of 17β-E2on regional and systemic lipolysis.MethodsSixteen postmenopausal women (age, 59±5 years; weight, 67±10 kg; and BMI, 24.8±2.9) were studied in a crossover design: i) placebo and ii) 4 mg E2. Basal and adrenaline-stimulated regional lipolysis was assessed by microdialysis and substrate oxidation rates by indirect calorimetry. Tissue biopsies were obtained to assess lipoprotein lipase activity and mRNA expression of adrenergic, estrogen, cytokine, and vascular reactivity receptors.ResultsAcute E2stimulation significantly attenuated catecholamine-stimulated lipolysis in femoral subcutaneous adipose tissue (interstitial glycerol concentration (micromole/liter) ANOVA time vs treatment interaction,P=0.01) and lipolysis in general in abdominal adipose tissue (ANOVA treatment alone,P<0.05). E2also reduced basal lipid oxidation ((mg/kg per min) placebo, 0.58±0.06 vs E2, 0.45±0.03;P=0.03) and induced a significantly higher expression of anti-lipolytic α2A-adrenergic receptor mRNA (P=0.02) in skeletal muscle tissue as well as an upregulation ofeNOS(NOS3) mRNA (P=0.02).ConclusionE2acutely attenuates the lipolytic response to catecholamines in subcutaneous adipose tissue, shifts muscular adrenergic receptor mRNA toward anti-lipolytic α2A-receptors, decreases whole body lipid oxidation, and enhances expression of markers of vascular reactivity.


Obesity ◽  
2014 ◽  
Vol 22 (8) ◽  
pp. 1821-1829 ◽  
Author(s):  
Miroslav Balaz ◽  
Marek Vician ◽  
Zuzana Janakova ◽  
Timea Kurdiova ◽  
Martina Surova ◽  
...  

2017 ◽  
Vol 123 (5) ◽  
pp. 1150-1159 ◽  
Author(s):  
Douglas W. Van Pelt ◽  
Lisa M. Guth ◽  
Jeffrey F. Horowitz

Alterations in the inflammatory state, metabolic function, and structure of subcutaneous adipose tissue (SAT) can impact the development of insulin resistance in obesity. Exercise can improve metabolic health in obesity, but the effects of exercise on SAT are not well known. The purpose of this study was to examine the effects of acute exercise and habitual exercise training on mRNA expression of markers of lipid metabolism, inflammation, fibrosis, and hypoxia/angiogenesis in SAT, as well as adipocyte cell size. We recruited overweight-to-obese adults who exercised regularly (ACTIVE: n = 8) or were sedentary (SED: n = 12). The groups were well matched for age (27 ± 1 vs. 24 ± 2 yr), body mass index (29 ± 1 vs. 27 ± 1 kg/m2), and body composition (30 ± 1 vs. 29 ± 1% body fat), but as expected, cardiorespiratory fitness was greater in ACTIVE vs. SED (V̇o2peak: 51 ± 3 vs. 42 ± 1 ml·kg fat-free mass−1·min−1; P = 0.01). Abdominal SAT biopsy samples were obtained before and 1 h after a single session of aerobic exercise (60 min at ~65% V̇o2peak). The exercise session increased SAT mRNA expression of VEGFA, an important regulator of angiogenic processes, in both groups. In addition, SAT from ACTIVE subjects had greater mRNA expression of the endothelial cell marker CD31 compared with SED, which may be a cumulative effect of the transient increases in VEGFA with regular exercise. We also magnetically sorted CD14+ immune cells from SAT samples and found that IL-6 expression was elevated in ACTIVE compared with SED. In conclusion, exercise initiates increases in factors related to angiogenic processes and may promote alterations in macrophage inflammation in SAT. NEW & NOTEWORTHY Acute exercise in overweight/obese adults increased subcutaneous adipose tissue (SAT) mRNA expression of VEGFA, an important regulator of angiogenesis and capillary growth. In addition, subjects that regularly exercise had elevated SAT CD31 mRNA expression and elevated IL-6 mRNA in adipose tissue macrophages compared with nonexercisers. This study demonstrates that aerobic exercise may alter processes related to whole body metabolic outcomes in obesity, such as angiogenesis and immune response, in the SAT of overweight/obese adults.


2000 ◽  
Vol 279 (2) ◽  
pp. E376-E385 ◽  
Author(s):  
Bente Stallknecht ◽  
Jens J. Larsen ◽  
Kari J. Mikines ◽  
Lene Simonsen ◽  
Jens Bülow ◽  
...  

Training increases insulin sensitivity of both whole body and muscle in humans. To investigate whether training also increases insulin sensitivity of adipose tissue, we performed a three-step hyperinsulinemic, euglycemic clamp in eight endurance-trained (T) and eight sedentary (S) young men [insulin infusion rates: 10,000 ( step I), 20,000 ( step II), and 150,000 ( step III) μU · min−1 · m−2]. Glucose and glycerol concentrations were measured in arterial blood and also by microdialysis in interstitial fluid in periumbilical, subcutaneous adipose tissue and in quadriceps femoris muscle (glucose only). Adipose tissue blood flow was measured by 133Xe washout. In the basal state, adipose tissue blood flow tended to be higher in T compared with S subjects, and in both groups blood flow was constant during the clamp. The change from basal in arterial-interstitial glucose concentration difference was increased in T during the clamp but not in S subjects in both adipose tissue and muscle [adipose tissue: step I ( n = 8), 0.48 ± 0.18 mM (T), 0.23 ± 0.11 mM (S); step II ( n = 8), 0.19 ± 0.09 (T), −0.09 ± 0.24 (S); step III( n = 5), 0.47 ± 0.24 (T), 0.06 ± 0.28 (S); (T: P < 0.001, S: P > 0.05); muscle: step I ( n = 4), 1.40 ± 0.46 (T), 0.31 ± 0.21 (S); step II ( n = 4), 1.14 ± 0.54 (T), −0.08 ± 0.14 (S); step III( n = 4), 1.23 ± 0.34 (T), 0.24 ± 0.09 (S); (T: P < 0.01, S: P > 0.05)]. Interstitial glycerol concentration decreased faster in T than in S subjects [half-time: T, 44 ± 9 min ( n = 7); S, 102 ± 23 min ( n = 5); P < 0.05]. In conclusion, training enhances insulin sensitivity of glucose uptake in subcutaneous adipose tissue and in skeletal muscle. Furthermore, interstitial glycerol data suggest that training also increases insulin sensitivity of lipolysis in subcutaneous adipose tissue. Insulin per se does not influence subcutaneous adipose tissue blood flow.


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