Effect of lifestyle modification on adipokine levels in obese subjects with insulin resistance

Diabetes Remission after Nonsurgical Intensive Lifestyle Intervention in Obese Patients with Type 2 Diabetes

Partial or complete remission from type 2 diabetes was recently observed after bariatric surgeries. Limited data is available about the possibility of inducing diabetes remission through intensive weight reduction. We retrospectively evaluated diabetes remissions after one year of the Weight Achievement and Intensive Treatment (Why WAIT) program, a 12-week intensive program for diabetes weight management in real-world clinical practice. Among 120 obese patients with type 2 diabetes who completed the program, 88 patients returned for follow-up at one year. Nineteen patients (21.6%) had major improvement in their glycemic control, defined as achieving an A1C <6.5% after one year. Four patients (4.5%) achieved either partial or complete diabetes remission defined as A1C <6.5% and <5.7%, respectively, on no antihyperglycemic medications for one year; 2 achieved partial remission (2.3%) and 2 achieved complete remission (2.3%). At the time of intervention, patients who achieved diabetes remission had shorter diabetes duration (<5 years) and lower A1C (<8%) and were treated with fewer than 2 oral medications. They achieved a weight reduction of >7% after 12 weeks. These results indicate that a subset of obese patients with type 2 diabetes is appropriate for intensive lifestyle intervention with the aim of inducing diabetes remission.

What is the most appropriate lipid profile ratio predictor for insulin resistance in each sex? A cross-sectional study in Korean populations (The Fifth Korea National Health and Nutrition Examination Survey)

BACKGROUND

Insulin resistance (IR) reduces reactivity of the target organ to blood insulin. Researchers have attempted to evaluate IR using various serum lipid concentration ratios. We aimed to determine the most strongly IR-predictive lipid profile ratios for each sex by studying associations between lipid concentration ratios and IR using data from the fifth Korea National Health and Nutrition Examination Survey (KNHANES V-1) 2010.

METHODS

Overall, 8958 individuals participated in health interview and examination surveys. Among them, 1910 individuals who completed physical examinations and 8-h fasting blood tests and were older than 20 years of age were enrolled (929 men and 981 women). The lipid-ratio-related study outcomes were the low-density lipoprotein cholesterol/high-density lipoprotein cholesterol (LDL-C/HDL-C), triglyceride (TG)/HDL-C, and non-HDL-C (LDL-C + TG/5)/HDL-C ratios. We divided subjects into 4 groups according to lipid profile ratio quartiles for a comparison of homeostasis model assessment (HOMA)-IR values. Regression analyses were performed after adjusting for the confounding factors of age, body mass index, and diabetes mellitus history.

RESULTS

HOMA-IR values tended to increase significantly along with LDL-C/HDL-C, TG/HDL-C, and non-HDL-C/HDL-C ratios in both sexes. In men, multiple linear regression analyses showed that after adjusting for confounding factors, a significant positive association remained only with the LDL-C/HDL-C ratio (p = 0.0238, R(2) = 0.3605, root mean squared error [MSE] =0.3512). In women, multiple linear regression analyses showed that after adjusting for confounding factors, significant positive associations remained with the LDL-C/HDL-C (p < 0.0001, R-square = 0.2329, root MSE = 0.3776), TG/HDL-C (p = 0.0001, R(2) = 0.2373, root MSE = 0.3766), and non-HDL-C/HDL-C ratios (p < 0.0001, R(2) = 0.2456, root MSE = 0.3745).

CONCLUSION

The LDL-C/HDL-C ratio in men and LDL-C/HDL-C, TG/HDL-C, and non-HDL-C/HDL-C ratios in women might be clinically significant predictors of IR in healthy Korean adults. However, additional large-scale studies are required to confirm these findings.

Cardiovascular complications of type 2 diabetes in youth

The prevalence of type 2 diabetes mellitus (T2DM) in youth has increased dramatically over the past decades. The literature also suggests that the progression from an impaired glucose tolerance state to established T2DM is more rapid in youth, compared to adults. The presence of significant cardiovascular complications in youth with T2DM, including cardiac, macrovascular, and microvascular remodeling, is another major issue in this younger cohort and poses a significant threat to the healthcare system. However, this issue is only now emerging as a major public health concern, with few data to support optimal treatment targets and strategies to reduce cardiovascular disease (CVD) risk in youth with T2DM. Accordingly, the purpose of this minireview is to better understand the cardiovascular complications in youth with T2DM. We briefly describe the pathophysiology from youth studies, including oxidative stress, inflammation, renin-angiotensin aldosterone system, and epigenetics, which link T2DM and CVD. We also describe the literature concerning the early signs of CVD in youth and potential treatment options to reduce cardiovascular risk.

Immune and Inflammatory Signaling Pathways in Exercise and Obesity

Over the last decades the combination of both a sedentary lifestyle and excessive food availability has led to a significant increase in the prevalence of obesity, which is increasingly recognized as an important risk factor for type 2 diabetes. Several lines of evidence exist demonstrating that expanded visceral adipose tissue produces several pro-inflammatory mediators that activate signaling pathways that contribute to the development of insulin resistance. Exercise training is an important lifestyle factor that is widely used as a tool for preventing and improving lifestyle-related obesity and insulin resistance. In this regard, exercise training is useful to increase energy expenditure thereby counteracting a positive energy balance. Exercise training is also able to attenuate the activation of several obesity-induced pathways of inflammation and oxidative stress. Thus, a better understanding of the molecular mechanisms and immune pathways in exercise, obesity, and diabetes can be extremely useful to exploit optimized lifestyle strategies to combat the increasing incidence of metabolic diseases.

Effects of body weight reduction on plasma leptin and adiponectin/leptin ratio in obese patients with type 1 diabetes mellitus

The aim of this study was to explore the changes in the adipokines leptin and adiponectin in obese patients with type 1 diabetes mellitus (T1DM) who underwent seven days of fasting and 21 days of low-calorie diet (LCD). The plasma leptin and adiponectin concentrations were measured in 14 obese patients with T1DM at baseline, immediately after 7 days of fasting, and after 21 days of LCD. 13 non-obese patients with T1DM were studied only after an overnight fasting. Bioimpedance technique was used for determination of body composition. Obese T1DM patients lost 6.0 kg (6.0; 6.8) (median, 25 %; 75 %) and decreased their fat tissue after fasting and LCD. Plasma leptin in obese T1DM was significantly higher than in non-obese T1DM patients: 9.10 (5.06; 25.89) vs. 1.71 (1.12; 7.08) microg . l(-1) and transiently decreased immediately after fasting: 3.45 microg . l(-1) (1.47; 7.00), (P<0.05). Adiponectin/leptin ratio in obese T1DM was significantly lower than in non-obese T1DM patients: 0.67 (0.57; 1.49) vs. 3.50 (2.46; 6.30) . 10(3) and transiently increased immediately after fasting: 2.22 (1.26; 3.24) . 10(3), (P<0.05). We conclude that obese patients with T1DM are characterized by hyperleptinemia that is reduced by prolonged fasting, but only slightly affected by low calorie diet.

The effects of aerobic exercise training at two different intensities in obesity and type 2 diabetes: implications for oxidative stress, low-grade inflammation and nitric oxide production

AIMS

To investigate the effect of 16 weeks of aerobic training performed at two different intensities on nitric oxide (tNOx) availability and iNOS/nNOS expression, oxidative stress (OS) and inflammation in obese humans with or without type 2 diabetes mellitus (T2DM).

METHODS

Twenty-five sedentary, obese (BMI > 30 kg/m2) males (52.8 ± 7.2 years); 12 controls versus 13 T2DM were randomly allocated to four groups that exercised for 30 min, three times per week either at low (Fat-Max; 30-40% VO(2max)) or moderate (T(vent); 55-65 % VO(2max)) intensity. Before and after training, blood and muscle samples (v. lateralis) were collected.

RESULTS

Baseline erythrocyte glutathione was lower (21.8 ± 2.8 vs. 32.7 ± 4.4 nmol/ml) and plasma protein oxidative damage and IL-6 were higher in T2DM (141.7 ± 52.1 vs. 75.5 ± 41.6 nmol/ml). Plasma catalase increased in T2DM after T(vent) training (from 0.98 ± 0.22 to 1.96 ± 0.3 nmol/min/ml). T2DM groups demonstrated evidence of oxidative damage in response to training (elevated protein carbonyls). Baseline serum tNOx were higher in controls than T2DM (18.68 ± 2.78 vs. 12.34 ± 3.56 μmol/l). Training at T(vent) increased muscle nNOS and tNOx in the control group only. Pre-training muscle nNOS was higher in controls than in T2DMs, while the opposite was found for iNOS. No differences were found after training for plasma inflammatory markers.

CONCLUSION

Exercise training did not change body composition or aerobic fitness, but improved OS markers, especially when performed at T(vent). Non-diabetics responded to T(vent) training by increasing muscle nNOS expression and tNOx levels in skeletal muscle while these parameters did not change in T2DM, perhaps due to higher insulin resistance (unchanged after intervention).

A comparison of a social support physical activity intervention in weight management among post-partum Latinas

BACKGROUND

Weight gain during the childbearing years and failure to lose pregnancy weight after birth contribute to the development of obesity in postpartum Latinas.

METHODS

Madres para la Salud [Mothers for Health] was a 12-month, randomized controlled trial exploring a social support intervention with moderate-intensity physical activity (PA) seeking to effect changes in body fat, fat tissue inflammation, and depression symptoms in sedentary postpartum Latinas. This report describes the efficacy of the Madres intervention.

RESULTS

The results show that while social support increased during the active intervention delivery, it declined to pre-intervention levels by the end of the intervention. There were significant achievements in aerobic and total steps across the 12 months of the intervention, and declines in body adiposity assessed with bioelectric impedance.

CONCLUSIONS

Social support from family and friends mediated increases in aerobic PA resulting in decrease in percent body fat.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01908959.

Markers of liver function and inflammatory cytokines modulation by aerobic versus resisted exercise training for nonalcoholic steatohepatitis patients

BACKGROUND

Non-alcoholic steatohepatitis is a growing public health problem with no approved therapy; as cytokines and other pro-inflammatory mediators may each play a role in transition of steatosis to NASH which is projected to be the leading cause of liver transplantation in the United States by 2020.

OBJECTIVE

The aim of this study was to compare the impact of aerobic versus resisted exercise training on inflammatory cytokines and markers of liver function in patients with nonalcoholic steatohepatitis.

MATERIAL AND METHODS

Fifty patients with NASH were included in the study and divided into two subgroups. Participants were included into 2 equal groups; the first group (A) received aerobic exercise training. The second group (B) received resisted exercise training three times a week for 3 months.

RESULTS

The mean values of TNF- α, IL6, IL8, ALT and AST were significantly decreased in group (A) and group (B). Also; there was a significant difference between both groups after treatment.

CONCLUSION

Aerobic exercise training modulates inflammatory cytokine levels and markers of liver function in patients with nonalcoholic steatohepatitis.

Sleep apnea-hypopnea syndrome and type 2 diabetes. A reciprocal relationship?

Epidemiological data suggest that sleep apnea-hypopnea syndrome (SAHS) is independently associated with the development of insulin resistance and glucose intolerance. Moreover, despite significant methodological limitations, some studies report a high prevalence of SAHS in patients with type 2 diabetes mellitus (DM2). A recent meta-analysis shows that moderate-severe SAHS is associated with an increased risk of DM2 (relative risk=1.63 [1.09 to 2.45]), compared to the absence of apneas and hypopneas. Common alterations in various pathogenic pathways add biological plausibility to this relationship. Intermittent hypoxia and sleep fragmentation, caused by successive apnea-hypopnea episodes, induce several intermediate disorders, such as activation of the sympathetic nervous system, oxidative stress, systemic inflammation, alterations in appetite-regulating hormones and activation of the hypothalamic-pituitary-adrenal axis which, in turn, favor the development of insulin resistance, its progression to glucose intolerance and, ultimately, to DM2. Concomitant SAHS seems to increase DM2 severity, since it worsens glycemic control and enhances the effects of atherosclerosis on the development of macrovascular complications. Furthermore, SAHS may be associated with the development of microvascular complications: retinopathy, nephropathy or diabetic neuropathy in particular. Data are still scant, but it seems that DM2 may also worsen SAHS progression, by increasing the collapsibility of the upper airway and the development of central apneas and hypopneas.

[Rosuvastatin improves insulin sensitivity in overweight rats induced by high fat diet. Role of SIRT1 in adipose tissue]

OBJECTIVE

To study the effects of rosuvastatin on insulin resistance in overweight rats induced by high fat diet, as well as potential mediators.

METHODS

We used male Wistar rats fed with a standard diet (CT) or high fat diet (33.5% fat) (HFD); half of the animals HFD were treated with rosuvastatin (15mg/kg/day) (HFD+Rosu) for 7 weeks.

RESULTS

HFD rats showed increased body, epididymal and lumbar adipose tissue weights. Treatment with Rosu did not modify body weight or the weight of the adipose packages in HFD rat. Plasma glucose and insulin levels and HOMA index were higher in HFD rats, and rosuvastatin treatment reduced them. Leptin/adiponectin ratio in plasma and lumbar adipose tissue were higher in HDF rats, and were reduced by rosuvastatin. SIRT-1, PPAR-γ and GLUT-4 protein expression in lumbar adipose tissue were lower in HFD rats and Rosu normalized expression of the three mediators.

CONCLUSIONS

Rosuvastatin ameliorates insulin sensitivity induced by HFD in rats. This effect is mediated by several mechanisms including reduction of leptin and enhancement of SIRT-1, PPAR-γ and GLUT-4 expression in white adipose tissue. SIRT1 could be considered a major mediator of the beneficial effects of rosuvastatin on insulin sensitivity in overweight rats induced by diet.

Adiponectin: a manifold therapeutic target for metabolic syndrome, diabetes, and coronary disease?

Adiponectin is the most abundant peptide secreted by adipocytes, being a key component in the interrelationship between adiposity, insulin resistance and inflammation. Central obesity accompanied by insulin resistance is a key factor in the development of metabolic syndrome (MS) and future macrovascular complications. Moreover, the remarkable correlation between coronary artery disease (CAD) and alterations in glucose metabolism has raised the likelihood that atherosclerosis and type 2 diabetes mellitus (T2DM) may share a common biological background. We summarize here the current knowledge about the influence of adiponectin on insulin sensitivity and endothelial function, discussing its forthcoming prospects and potential role as a therapeutic target for MS, T2DM, and cardiovascular disease. Adiponectin is present in the circulation as a dimer, trimer or protein complex of high molecular weight hexamers, >400 kDa. AdipoR1 and AdipoR2 are its major receptors in vivo mediating the metabolic actions. Adiponectin stimulates phosphorylation and AMP (adenosin mono phosphate) kinase activation, exerting direct effects on vascular endothelium, diminishing the inflammatory response to mechanical injury and enhancing endothelium protection in cases of apolipoprotein E deficiency. Hypoadiponectinemia is consistently associated with obesity, MS, atherosclerosis, CAD, T2DM. Lifestyle correction helps to favorably modify plasma adiponectin levels. Low adiponectinemia in obese patients is raised via continued weight loss programs in both diabetic and nondiabetic individuals and is also accompanied by reductions in pro-inflammatory factors. Diet modifications, like intake of fish, omega-3 supplementation, adherence to a Mediterranean dietary pattern and coffee consumption also increase adiponectin levels. Antidiabetic and cardiovascular pharmacological agents, like glitazones, glimepiride, angiotensin converting enzyme inhibitors and angiotensin receptor blockers are also able to improve adiponectin concentration. Fibric acid derivatives, like bezafibrate and fenofibrate, have been reported to enhance adiponectin levels as well. T-cadherin, a membrane-associated adiponectin-binding protein lacking intracellular domain seems to be a main mediator of the antiatherogenic adiponectin actions. The finding of novel pharmacologic agents proficient to improve adiponectin plasma levels should be target of exhaustive research. Interesting future approaches could be the development of adiponectin-targeted drugs chemically designed to induce the activaton of its receptors and/or postreceptor signaling pathways, or the development of specific adiponectin agonists.

Perivascular adipose tissue and coronary vascular disease

Coronary perivascular adipose tissue is a naturally occurring adipose tissue depot that normally surrounds the major coronary arteries on the surface of the heart. Although originally thought to promote vascular health and integrity, there is a growing body of evidence to support that coronary perivascular adipose tissue displays a distinct phenotype relative to other adipose depots and is capable of producing local factors with the potential to augment coronary vascular tone, inflammation, and the initiation and progression of coronary artery disease. The purpose of the present review is to outline previous findings about the cardiovascular effects of coronary perivascular adipose tissue and the potential mechanisms by which adipose-derived factors may influence coronary vascular function and the progression of atherogenesis.

Changes in inflammatory markers after sleeve gastrectomy in patients with impaired glucose homeostasis and type 2 diabetes

BACKGROUND

Bariatric surgery is an effective treatment for morbid obesity. Obesity and type 2 diabetes are associated with chronic inflammation. There is lack of data examining the effects of sleeve gastrectomy (SG) on inflammatory biomarkers. Our aim was to study the effects of SG on specific cytokines associated with obesity including interleukin-6 (IL-6), interleukin-10 (IL-10), leptin, adiponectin, and C-reactive protein (CRP) preoperatively, 1 and 6 months after surgery.

METHODS

A nonrandomized prospective study comprising of 22 participants with impaired glucose homeostasis and type 2 diabetes undergoing SG (body mass index 50.1 kg/m(2), glycated hemoglobin [HbA1c] 53 mmol/mol). Serial measurements of IL-6, IL-10, leptin, adiponectin, and CRP were performed during oral glucose tolerance testing preoperatively, 1 and 6 months postoperatively.

RESULTS

We observed significant improvements at 1 and 6 months in leptin (P≤.001) and CRP (P = .003) after SG. We also observed a significant reduction in IL-6 at 6 months (P = .001). No statistically significant differences were observed for adiponectin and IL-10.

CONCLUSION

This study is the first to examine the detailed changes in the inflammatory cytokines after SG. Our study shows significant improvements in the inflammatory biomarkers after SG in patients with impaired glucose homeostasis and type 2 diabetes.

Endothelial function increases after a 16-week diet and exercise intervention in overweight and obese young women

Weight loss improves endothelial function in overweight individuals. The effects of weight loss through combined aerobic and resistance training and caloric restriction on in vivo vascular measures and blood markers associated with the regulation of endothelial function have not been comprehensively examined. Therefore, we investigated brachial artery endothelial function and potential regulatory blood markers in twenty overweight women (30.3 ± 2.0 years) who participated in 16 weeks of aerobic (5 d/wk) and resistance training (2 d/wk) (combined: ≥250 kcal/d) and caloric restriction (−500 kcal/d versus requirement). Resting brachial artery flow mediated dilation (FMD) and circulating endothelin-1 (ET-1) and interleukin-6 (IL-6) were assessed at baseline and following the intervention. Relative and absolute FMD increased (before: 4.0 ± 0.5% versus after: 6.9 ± 0.6%, P < 0.05, and before: 0.14 ± 0.02 mm versus after: 0.23 ± 0.02 mm, P < 0.05, resp.), while body mass decreased (before: 86.9 ± 2.4 kg versus after: 81.1 ± 2.4 kg, P < 0.05) following the intervention. There were no changes in either blood marker (IL-6: before: 1.5 ± 0.2 pg/mL versus after: 1.5 ± 0.1 pg/mL, P > 0.05, and ET-1: before: 0.55 ± 0.05 pg/mL versus after: 0.59 ± 0.09 pg/mL, P > 0.05). 16 weeks of combined aerobic/resistance training and diet-induced weight loss improved endothelial function in overweight and obese young women, but this increase was not associated with changes in blood markers of vasoconstriction or inflammation.

Extract from Edible Red Seaweed (Gelidium amansii) Inhibits Lipid Accumulation and ROS Production during Differentiation in 3T3-L1 Cells

Gelidium (G.) amansii is a red alga widely distributed in the shallow waters around East Asian countries. We investigated the effect of G. amansii on lipid accumulation and ROS (Reactive Oxygen Species) production in 3T3-L1 cells. G. amansii extracts dose-dependently inhibited lipid formation and ROS generation in cultured cells. Our results showed that anti-adipogenic effect of G. amansii was due to the reduction in mRNA expressions of PPARγ peroxisome proliferator-activated receptor-γ and aP2 (adipocyte protein 2). G. amansii extracts significantly decreased mRNA levels of a ROS-generator, NOX4 (nicotinamide adenine dinucleotide phosphate hydrogen oxidase 4), and increased the protein levels of antioxidant enzymes including SOD1/2 (superoxide dis-mutases), Gpx (glutathione peroxidase), and GR (glutathione reductase), which can lead to the reduction of ROS in the cell. In addition, the G. amansii extract enhanced mRNA levels of adiponectin, one of the adipokines secreted from adipocytes, and GLUT4, glucose uptake protein. Taken together, our study shows that G. amansii extract inhibited lipid accumulation and ROS production by controlling adipogenic signals and ROS regulating genes.

Insulin Sensitivity Following Exercise Interventions: Systematic Review and Meta-Analysis of Outcomes Among Healthy Adults

OBJECTIVE

Although exercise can improve insulin sensitivity, no adequate synthesis exists of exercise intervention studies with regard to their effect on insulin sensitivity. This comprehensive meta-analysis synthesized the insulin sensitivity outcomes of supervised exercise interventions.

METHOD

Extensive literature searching located published and unpublished intervention studies that measured insulin sensitivity outcomes. Eligible studies tested supervised exercise interventions among healthy adults. Primary study characteristics and results were coded. Random-effects meta-analyses of standardized mean differences included moderator analyses.

RESULTS

Data were synthesized across 2509 subjects (115 samples, 78 reports). The overall mean effect size for 2-group postintervention comparisons was 0.38 (95% confidence interval [CI] = 0.25-0.51, I (2) = 0%) and for 2-group pre-post comparisons was 0.43 (95% CI = 0.30-0.56, I (2) = 52%; higher mean insulin sensitivity for treatment than control subjects). The postintervention mean of 0.38 is consistent with treatment subjects ending studies with a mean fasting insulin of 6.8 mU/L if control participants' mean fasting insulin were 7.9 mU/L. Exploratory moderator analyses did not document different insulin sensitivity effect sizes across intervention characteristics or sample attributes.

CONCLUSION

This study documented that exercise is a valuable primary care and community health strategy for healthy adults to improve insulin sensitivity and lower the risk for diabetes conferred by insulin resistance.

Effects of a walking intervention using mobile technology and interactive voice response on serum adipokines among postmenopausal women at increased breast cancer risk

Practical methods to reduce the risk of obesity-related breast cancer among high-risk subgroups are lacking. Few studies have investigated the effects of exercise on circulating adipokines, which have been shown to be associated with obesity and breast cancer. The aim of this study was to examine the effects of a walking intervention on serum adiponectin, leptin, and the adiponectin-to-leptin ratio (A/L). Seventy-one overweight and obese postmenopausal women at increased risk of developing breast cancer were stratified by BMI (25-30 kg/m(2) or >30 kg/m(2)) and randomized to a 12-week, two-arm walking intervention administered through interactive voice response (IVR) and mobile devices. The intervention arms were IVR + coach and IVR + no-coach condition. Pre-post changes in serum adiponectin, leptin, and the A/L ratio were examined using mixed regression models, with ratio estimates (and 95 % confidence intervals [CI]) corresponding to postintervention adipokine concentrations relative to preintervention concentrations. While postintervention effects included statistically significant improvements in anthropometric measures, the observed decreases in adiponectin and leptin (ratio = 0.86, 95 % CI 0.74-1.01, and ratio = 0.94, 95 % CI 0.87-1.01, respectively) and increase in A/L ratio = 1.09, 95 % CI 0.94-1.26) were not significant. Thus, these findings do not support significant effects of the walking intervention on circulating adipokines among overweight and obese postmenopausal women. Additional studies are essential to determine the most effective and practical lifestyle interventions that can promote beneficial modification of serum adipokine concentrations, which may prove useful for obesity-related breast cancer prevention.

Lifestyle modification and endothelial function in obese subjects

The metabolic syndrome is a cluster of metabolic and vascular abnormalities that include central obesity, insulin resistance, hyperinsulinemia, glucose intolerance, hypertension, dyslipidemia, hypercoagulability and an increased risk of coronary and cerebral vascular disease. These metabolic and vascular abnormalities are the main cause of cardiovascular mortality in western societies. Endothelial dysfunction, an early step in the development of atherosclerosis, has been reported in obese nondiabetic individuals and in patients with Type 2 diabetes. It has also been observed in individuals at high risk for Type 2 diabetes, including those with impaired glucose tolerance and the normoglycemic first-degree relatives of Type 2 diabetic patients. Recent evidence points to adipocytes as a complex and active endocrine tissue whose secretory products, including free fatty acids and several cytokines (i.e., leptin, adiponectin, tissue necrosis factor-alpha, interleukin-6, and resistin) play a major role in the regulation of human metabolic and vascular biology. These adipocytokines have been claimed to be the missing link between insulin resistance and cardiovascular disease. Interventions designed to improve endothelial and/or adipose-tissue functions may reduce cardiovascular events in obese individuals with either the metabolic syndrome or Type 2 diabetes. Lifestyle modification in the form of caloric restriction and increased physical activity are the most common modalities used for treating those individuals at risk and is unanimously agreed to be the initial step in managing Type 2 diabetes. Several recent studies have demonstrated favorable impacts of lifestyle modifications in improving endothelial function and insulin sensitivity, in addition to altering serum levels of adipocytokines and possibly reducing cardiovascular events. This review discusses current knowledge of the role of lifestyle modifications in ameliorating cardiovascular risk in obese subjects with either the metabolic syndrome or Type 2 diabetes.

Adiposopathy: how do diet, exercise and weight loss drug therapies improve metabolic disease in overweight patients?

An increase in bodyweight is generally associated with an increased risk of excessive fat-related metabolic diseases (EFRMD), including Type 2 diabetes mellitus, hypertension and dyslipidemia. However, not all patients who are overweight have EFRMD, and not all patients with EFRMD are significantly overweight. The adipocentric paradigm provides the basis for a unifying, pathophysiological process whereby fat gain in susceptible patients leads to fat dysfunction ('sick fat'), and wherein pathological abnormalities in fat function (adiposopathy) are more directly related to the onset of EFRMD than increases in fat mass (adiposity) alone. But just as worsening fat function worsens EFRMD, improved fat function improves EFRMD. Peroxisome proliferator-activated receptor-gamma agonists increase the recruitment, proliferation and differentiation of preadipocytes ('healthy fat') and cause apoptosis of hypertrophic and dysfunctional (including visceral) adipocytes resulting in improved fat function and improved metabolic parameters associated with EFRMD. Weight loss interventions, such as a hypocaloric diet and physical exercise, in addition to agents such as orlistat, sibutramine and cannabinoid receptor antagonists, may have favorable effects upon fat storage (lipogenesis and fat distribution), nutrient metabolism (such as free fatty acids), favorable effects upon adipose tissue factors involved in metabolic processes and inflammation, and enhanced 'cross-talk' with other major organ systems. In some cases, weight loss therapeutic agents may even affect metabolic parameters and adipocyte function independently of weight loss alone, suggesting that the benefit of these agents in improving EFRMD may go beyond their efficacy in weight reduction. This review describes how adiposopathy interventions may affect fat function, and thus improve EFRMD.

Impact of moderate versus mild aerobic exercise training on inflammatory cytokines in obese type 2 diabetic patients: a randomized clinical trial

BACKGROUND

Recently some plasma biomarkers of inflammation have been recognized as important cardiovascular risk factors. There is little information about the effects of aerobic exercise training on these biomarkers and the risk of metabolic complications in obese type 2 diabetes patients.

OBJECTIVE

To compare the impact of moderate versus mild aerobic exercise training on the inflammatory cytokines in obese type 2 diabetic patients.

METHODS

Fifty obese type 2 diabetic patients of both sexes with body mass index (BMI) varying from 31 to 36 kg/m(2), non smokers, free from respiratory, kidney, liver, metabolic and neurological disorders, participated in this study. Their age ranged from 40 to 55 years. The subjects were included into two equal groups; the first group (A) received moderate aerobic exercise training. The second group (B) received mild aerobic exercise training, three times / week for 3 months.

RESULTS

The mean values of leptin, TNF- alpha, IL2, IL4, IL6, HOMA-IR and HBA1c were significantly decreased in group (A) and group (B). Also, there were significant differences between both groups after treatment.

CONCLUSION

Moderate aerobic exercise training modulates inflammatory cytokines more than mild aerobic exercise training in obese type 2 diabetic patients.

Effect of the Mediterranean diet on plasma adipokine concentrations in men with metabolic syndrome

OBJECTIVE

While a Mediterranean dietary pattern (MedDiet) has been associated with favorable changes in several features of metabolic syndrome (MetS), its impact on plasma adipokine concentrations remains largely unknown. The objective of this study was to determine the impact of the MedDiet consumed under controlled feeding conditions, without (-WL) and with weight loss (+WL), on plasma adipokine concentrations in adult men with MetS (NCEP-ATP III).

MATERIALS/METHODS

The diet of 26 men with MetS (age 24 to 62 yrs) was first standardized to a North American control diet for 5 weeks. Participants then consumed a pre-determined MedDiet for 5 weeks. Both diets were consumed under weight-maintaining isoenergetic feeding conditions. Participants then underwent a 20-week free-living caloric restriction period, after which they consumed the MedDiet again in weight stabilizing, isoenergetic feeding conditions.

RESULTS

Body weight was reduced by 10.2%±2.9% and waist circumference by 8.6±3.3 cm after the weight loss period and stabilization on MedDiet (P<0.001). MedDiet-WL had no impact on plasma concentrations of leptin, plasminogen activator inhibitor-1, resistin, visfatin, acylation stimulating protein and adiponectin. MedDiet+WL reduced plasma leptin concentrations (P<0.01) and increased plasma adiponectin concentrations (P<0.05) compared with the control diet and MedDiet-WL.

CONCLUSION

Data from this nutritionally controlled study suggest that short-term consumption of MedDiet has little effect on the concentrations of many adipokines in the absence of weight loss.

Factors involved in rosuvastatin induction of insulin sensitization in rats fed a high fat diet

BACKGROUND AND AIM

To investigate whether rosuvastatin can improve insulin sensitivity in overweight rats having a high fat diet (HFD). The potential mechanisms involved in this action were evaluated, including SIRT-1, other factors involved in glucose metabolism and stress signaling pathways.

METHODS AND RESULTS

Male Wistar rats (n = 30) were divided into three groups: (i) rats fed a standard diet (3.5% fat); (ii) rats fed a HFD (33.5% fat); and (iii) rats fed a HFD and treated with rosuvastatin (15 mg/kg/day). Evolution: 7 weeks. HFD rats showed increased body, epididymal and lumbar adipose tissue weights. Plasma levels of cholesterol, triglycerides, VLDL, glucose and insulin and leptin/adiponectin ratio were higher in HFD rats, and rosuvastatin treatment reduced them. SIRT-1, p53, PGC-1α, PPAR-γ and GLUT-4 protein levels in white adipose tissue (WAT) were lower, and JNK was higher in HFD rats compared to controls. Rosuvastatin treatment normalized expression of these mediators. Endothelium-dependent relaxation was reduced in mesenteric rings from HFD rats compared to controls and rosuvastatin enhanced it in HFD rats.

CONCLUSION

Rosuvastatin treatment reduced insulin resistance without affecting body weight or WAT loss in HFD rats. Reduction of leptin and JNK, and enhancement of SIRT-1, p53, PGC-1α, PPAR-γ and GLUT-4 expression in WAT could contribute to insulin sensitization. Normalization of SIRT-1 expression in WAT could be considered a key novel mechanism that aids in explaining the beneficial effects of rosuvastatin on the amelioration of glucose metabolism and the arrangement of multiple signaling pathways participating in insulin resistance in overweight HFD rats.

The relationship between gut and adipose hormones, and reproduction

BACKGROUND

Reproductive function is tightly regulated by nutritional status. Indeed, it has been well described that undernutrition or obesity can lead to subfertility or infertility in humans. The common regulatory pathways which control energy homeostasis and reproductive function have, to date, been poorly understood due to limited studies or inconclusive data. However, gut hormones and adipose tissue hormones have recently emerged as potential regulators of both energy homeostasis and reproductive function.

METHODS

A PubMed search was performed using keywords related to gut and adipose hormones and associated with keywords related to reproduction.

RESULTS

Currently available evidence that gut (ghrelin, obestatin, insulin, peptide YY, glucagon-like peptide-1, glucose-dependent insulinotropic peptide, oxyntomodulin, cholecystokinin) and adipose hormones (leptin, adiponectin, resistin, omentin, chemerin) interact with the reproductive axis is presented. The extent, site and direction of their effects on the reproductive axis are variable and also vary depending on species, sex and pubertal stage.

CONCLUSIONS

Gut and adipose hormones interact with the reproductive axis as well as with each other. While leptin and insulin have stimulatory effects and ghrelin has inhibitory effects on hypothalamic GnRH secretion, there is increasing evidence for their roles in other sites of the reproductive axis as well as evidence for the roles of other gut and adipose hormones in the complex interplay between nutrition and reproduction. As our understanding improves, so will our ability to identify and design novel therapeutic options for reproductive disorders and accompanying metabolic disorders.

Exercise training attenuates adipose tissue fibrosis in diet-induced obese mice

Tissue fibrosis, such as that which occurs in obesity, is associated with chronic inflammatory diseases. Although regular exercise reduces adipose tissue inflammation, the mechanisms regulating the effects of exercise on adipose tissue fibrosis are unclear. This study aimed to clarify whether exercise training attenuates adipose tissue fibrosis with consequent reduction of extracellular matrix including collagens. Male C57BL/6J (4-week old) mice were randomly assigned to four groups that received a normal diet (ND) plus sedentary (n=8), an ND plus exercise training (n=8), a high-fat diet (HFD) plus sedentary (n=12), and an HFD plus exercise training (n=12). Mice were fed the ND or HFD from 4 to 20 weeks of age. The exercise groups were trained on a motorized treadmill for 60 min/day, 5 times/week over the same period. Histological hepatic fibrosis detected by Sirius red and α-smooth muscle actin staining were attenuated in HFD exercise mice compared with HFD sedentary mice. mRNA levels of transforming growth factor-β and tissue inhibitors of metalloproteinase-1, major regulators of tissue fibrosis, were increased in HFD sedentary mice but were attenuated in HFD exercise mice. Similarly, adipose tissue from the HFD sedentary mice contained higher macrophages than adipose tissue from the ND mice, and this was also lowered by exercise training. These findings suggest that exercise training may be effective for attenuating adipose tissue inflammation in obesity.

Should visceral fat be reduced to increase longevity?

Several epidemiologic studies have implicated visceral fat as a major risk factor for insulin resistance, type 2 diabetes mellitus, cardiovascular disease, stroke, metabolic syndrome and death. Utilizing novel models of visceral obesity, numerous studies have demonstrated that the relationship between visceral fat and longevity is causal while the accrual of subcutaneous fat does not appear to play an important role in the etiology of disease risk. Specific recommended intake levels vary based on a number of factors, including current weight, activity levels, and weight loss goals. It is discussed the need of reducing the visceral fat as a potential treatment strategy to prevent or delay age-related diseases and to increase longevity.

Do synovial leptin levels correlate with pain in end stage arthritis?

PURPOSE

We evaluated whether synovial fluid (SF) leptin concentrations correlate with pain severity in patients with hip or knee endstage osteoarthritis (OA) and whether they mediate the association between increased joint pain and (1) female gender and (2) obesity.

METHODS

We conducted a cross-sectional study including patients with primary hip and knee OA undergoing joint replacement between January and December 2010. SF leptin concentrations obtained on the day of surgery were assessed. Main outcome was pain severity measured pre-operatively using WOMAC and VAS pain scales.

RESULTS

A total of 219 patients were included, 123 hip and 96 knee arthroplasties. Mean age was 72 years, 59% were women. Mean SF leptin levels were 22.9 (±25.6) ng/ml in women and 5.4 (±5.9) ng/ml in men. Levels >19.6 ng/ml (highest quartile) were significantly associated with increased pain on both WOMAC (mean difference -9.6, 95% CI -15.1 to -4.0) and VAS scale (mean difference 0.8, 95% CI 0.2-1.3). Associations remained unchanged after adjusting for age, co-morbidities, contra-lateral arthritic joint, OA site, and disability. The associations observed between increased pain and female gender or obesity were substantially reduced after adjusting for SF leptin.

CONCLUSION

Joint pain is associated with SF leptin concentrations. Increased pre-operative pain observed in women and obese may be related to high intra-articular leptin levels.

Should visceral fat, strictly linked to hepatic steatosis, be depleted to improve survival?

Numerous epidemiologic studies have implicated abdominal obesity as a major risk factor for insulin resistance, type 2 diabetes mellitus, cardiovascular disease, stroke, metabolic syndrome and its further expression, i.e., nonalcoholic fatty liver disease and death. Using novel models of visceral obesity, several studies have demonstrated that the relationship between visceral fat and longevity is causal, while the accrual of subcutaneous fat does not appear to play an important role in the etiology of disease risk. The need of reducing the visceral fat to improve survival, mainly taking into account the strict link between nonalcoholic fatty liver disease and the coronary artery disease is discussed.

Fatty acid-binding protein 2 Ala54Thr genotype is associated with insulin resistance and leptin levels changes after a high monounsaturated fat diet in obese non-diabetic patients

BACKGROUND

It has been found that the expression of fatty acid binding protein 2 (FABP2) mRNA is under dietary control. This polymorphism was associated with high insulin resistance, and fasting insulin concentrations.

OBJECTIVE

The aim of our study was to investigate the influence of Thr54 polymorphism in the FABP2 gene on metabolic response, weight loss and serum adipokine levels secondary to a high monounsaturated fat hypocaloric diet.

DESIGN

A sample of 122 obese patients was analyzed in a prospective way. The hypocaloric diet had 1342 kcal, 46.6% of carbohydrates, 34.1% of lipids and 19.2% of proteins, with a 67.5% of monounsaturated fats, and lasted 3 months.

RESULTS

Fifty-five patients (45.1%) had the genotype Ala54/Ala54 (wild group) and 67 (64.9%) patients a mutant genotype, Ala54/Thr54 (54 patients, 44.3%) or Thr54/Thr54 (13 patients, 10.7%). In wild group, body mass index (-1.5±1.2 kg/m2), weight (-4.1±3.6 kg), fat mass (-3.6±3.3 kg), waist circumference (-4.9±2.9 cm), insulin (-1.7±3.6 mUI/l), homeostasis model assessment of insulin resistance (HOMA-IR) (-0.6±1.8 units) and leptin levels decreased (-7.6±7.1 ng/ml). In mutant group, anthropometric parameters improved, without changes in biochemical parameters.

CONCLUSION

Carriers of Thr54 allele have a different response than wild type obese, with a lack of decrease of insulin levels, leptin levels and HOMA-IR.

Combined ethanol extract of grape pomace and omija fruit ameliorates adipogenesis, hepatic steatosis, and inflammation in diet-induced obese mice

The aim of this study was to evaluate the long-term effects of grape pomace ethanol extract (GPE) with or without omija fruit ethanol extract (OFE) on adiposity, hepatic steatosis, and inflammation in diet-induced obese mice. Male C57BL/6J mice were fed a high-fat diet (HFD) as the control diet and HFD plus GPE (0.5%, w/w) with or without OFE (0.05%, w/w) as the experimental diet for 12 weeks. GPE alone did not significantly affect adipogenesis and hepatic steatosis. However, the supplementation of GPE + OFE significantly lowered body weight gain, white adipose tissue weight, adipocyte size, and plasma free fatty acid and adipokines (leptin, PAI-1, IL-6, and MCP-1) levels in HFD-fed mice compared to those of the control group. These beneficial effects of GPE + OFE were partly related to the decreased expression of lipogenic and inflammatory genes in white adipose tissue. GPE + OFE supplementation also significantly lowered liver weight and ameliorated fatty liver by inhibiting expression of hepatic genes involved in fatty acid and cholesterol syntheses as well as inflammation and by activating hepatic fatty acid oxidation. These findings suggest that the combined ethanol extract of grape pomace and omija fruit has the potential to improve adiposity and fatty liver in diet-induced obese mice.

Regular exercise modulates obesity factors and body composition in sturdy men

The purpose of this study was to find the change and correlation between obesity factors and body composition according to regular exercise. Thirty-six sturdy men at twenty years old in 'K' university students were participated in this study. The subjects were randomly divided into two groups (n= 18 in each group): control group and regular exercise group. Exercise program composed of three programs: warm-up (10 min), work-out (30-60 min), cool-down (10 min), and categorized by five days per week for eight weeks. Aerobic exercise using a treadmill at 60% of heart rate reserve was performed, and weight training was composed of nine different exercises for the large muscles. Before the performing regular exercise, there was no significant difference between control and regular exercise groups. In the present results, 8 weeks regular exercise significantly decreased leptin, weight, fat mass, % fat, waist to hip ratio (WHR), and body mass index (BMI) more than compared to before performing regular exercise, whereas significantly enhanced lean mass more than compared to before performing regular exercise. Furthermore, regular exercise group reduced leptin, weight, fat mass, % fat, WHR, and BMI compared to control group in the post test. In the correlation of obesity-related factors and body composition, tumor necrosis factor-α (TNF-α) showed correlation with weight, lean mass, and fat mass after performing regular exercise. Here in this study, we suggest that regular exercise is a valuable tool for the improvement of health in the sturdy men, because regular exercise suppresses body fat and obesity-related factors.

N-3 polyunsaturated fatty acids: relationship to inflammation in healthy adults and adults exhibiting features of metabolic syndrome

Individuals with metabolic syndrome (MetS) have a higher risk of type 2 diabetes and cardiovascular disease, therefore, research has been directed at reducing various components that contribute to MetS and associated metabolic impairments, including chronic low-grade inflammation. Epidemiological, human, animal and cell culture studies provide evidence that dietary n-3 polyunsaturated fatty acids (n-3 PUFA), including alpha-linolenic acid (18:3n-3, ALA), eicosapentaenoic acid (20:5n-3, EPA) and/or docosahexaenoic acid (22:6n-3, DHA) may improve some of the components associated with MetS. The current review will discuss recent evidence from human observational and intervention studies that focused on the effects of ALA, EPA or DHA on inflammatory markers in healthy adults and those with one or more features of MetS. Observational studies in healthy adults support the recommendation that a diet rich in n-3 fatty acids may play a role in preventing and reducing inflammation, whereas intervention studies in healthy adults have yielded inconsistent results. The majority of intervention studies in adults with features of MetS have reported a benefit for some inflammatory measures; however, other studies using high n-3 fatty acid doses and long supplementation periods have reported no effect. Overall, the data reviewed herein support recommendations for regular fatty fish consumption and point toward health benefits in terms of lowering inflammation in adults with one or more features of MetS.

Nordic walking decreased circulating chemerin and leptin concentrations in middle-aged men with impaired glucose regulation

BACKGROUND

Dysfunction of adipose tissue is one of the major factors leading to insulin resistance. Altered adipokine concentration is an early sign of adipose tissue dysfunction. The aim of this study was to assess the impact of exercise intervention on adipokine profile, glycemic control, and risk factors of the metabolic syndrome (MeS) in men with impaired glucose regulation (IGR).

METHODS

Overweight and obese men with IGR (n =144) aged 40-65 years were studied at baseline and at 12 weeks in a randomized controlled multicenter intervention study. BMI varied from 25.1 to 34.9. The subjects were randomized into one of three groups: 1) a control group (C; n =47), 2) a Nordic walking group (NW; n =48), or 3) a resistance training group (RT; n =49).

RESULTS

Leptin concentrations decreased in the NW group compared to both other groups. Both types of exercise intervention significantly decreased serum chemerin concentrations compared to the C group. In the NW group also body fat percentage, fatty liver index (FLI), and total and LDL cholesterol concentrations decreased compared to the RT group.

CONCLUSIONS

Nordic walking intervention seems to decrease chemerin and leptin levels, and subjects in this intervention group achieved the most beneficial effects on components of MeS.

Plasma levels of resistin and ghrelin before and after treatment in patients with hyperthyroidism

OBJECTIVE

To investigate ghrelin and resistin concentrations in patients with hyperthyroidism before and after restoration to a euthyroid state and to correlate the 2 peptides with anthropometric and insulin resistance parameters.

METHODS

The study included hyperthyroid patients and euthyroid healthy participants as a control group. Hyperthyroid patients were evaluated at the start of the study and after normalization of thyroid function with appropriate antithyroid drugs. Anthropometric parameters, insulin resistance parameters (fasting blood glucose, fasting insulin, and homeostasis model assessment-insulin resistance), thyroid function tests, and measurement of ghrelin and resistin were assessed in patients and control participants.

RESULTS

The study included 40 hyperthyroid patients (32 women and 8 men, aged 26-42 years) and 30 euthyroid healthy participants (20 women and 10 men, aged 25-43 years) as a control group. In hyperthyroid patients, serum resistin levels and insulin resistance parameters were higher and plasma ghrelin levels were lower than in control participants (P<.001), and all normalized after treatment. Ghrelin levels were correlated only with insulin resistance parameters, but no correlations with any anthropometric or laboratory data were found. Resistin levels did not correlate with any clinical or laboratory data of hyperthyroid patients.

CONCLUSION

In hyperthyroid patients, resistin was increased and ghrelin was decreased, they were not related to anthropometric parameters, and they normalized after treatment of hyperthyroidism.

The IL-6 Gene G-174C Polymorphism Related to Health Indices in Greek Primary School Children

Interleukin-6 (IL-6) is a pleiotropic cytokine expressed in many tissues. A polymorphism in the IL-6 gene, associated with differences in IL-6 transcription rate, has been recently described. Subjects with the -174GG genotype are prone to lipid abnormalities. We investigated the effect of the G-174C IL-6 polymorphism on health indices and lipid values of 184 Greek primary school children. The genotype distribution of the polymorphism was 37.5% for GG and 52.2% and 10.3% for GC and CC, respectively. No differences were observed between genotype distribution and gender (p = 0.37). Boys homozygous for the G allele showed higher triglyceride levels than boys carrying the C allele (86 +/- 28 vs. 74 +/- 20 mg/dL, p = 0.02) and lower mid-upper arm muscle circumference (17.46 +/- 1.86 vs. 18.91 +/- 2.53 cm, p = 0.013). In addition, girls homozygous for the G allele had higher values for suprailiac skinfolds compared with those bearing the C allele (21.28 +/- 12.56 vs. 17.09 +/- 13.36 mm, p = 0.06). These findings were confirmed by multiple linear regression analysis, after controlling for age, sex, BMI, energy and total fat intake, and weekly physical activity. From the results of the present study, we concluded that individuals homozygous for G allele on the IL-6 gene have higher values in some parameters associated with obesity.

Circulating adiponectin is associated with renal function independent of age and serum lipids in west africans

Adiponectin, a protein secreted by adipose tissue, has been associated with renal dysfunction. However, these observations have not been adequately investigated in large epidemiological studies of healthy individuals in general and in African populations in particular. Hence, we designed this study to evaluate the relationship between adiponectin and renal function in a large group of nondiabetic West Africans. Total adiponectin was measured in 792 participants. MDRD and Cockroft-Gault (CG-) estimated GFR were used as indices of renal function. Linear and logistic regression models were used to determine the relationship between adiponectin and renal function. Adiponectin showed an inverse relationship with eGFR in univariate (Beta_MDRD = −0.18, Beta_CG = −0.26) and multivariate (Beta_MDRD = −0.10, Beta_CG = −0.09) regression analyses. The multivariate models that included age, sex, BMI, hypertension, smoking, HDL-C, LDL-C, triglycerides, and adiponectin explained 30% and 55.6% of the variance in GFR estimated by MDRD and CG methods, respectively. Adiponectin was also a strong predictor of moderate chronic kidney disease (defined as eGFR < 60 mL/min/1.73 m²). We demonstrate that adiponectin is associated with renal function in nondiabetic West Africans. The observed relationship is independent of age and serum lipids. Our findings suggest that adiponectin may have clinical utility as a biomarker of renal function.

Exercise-induced Signals for Vascular Endothelial Adaptations: Implications for Cardiovascular Disease

This article reviews recent advances in our understanding of hemodynamic signals, external/compressive forces, and circulating factors that mediate exercise training-induced vascular adaptations, with particular attention to the roles of these signals in prevention and treatment of endothelial dysfunction and cardiovascular (CV) diseases.

Effects of diet-induced obesity on protein expression in insulin signaling pathways of skeletal muscle in male Wistar rats

BACKGROUND

The prevalence of diet-induced obesity is increasing globally, and posing significant health problems for millions of people worldwide. Diet-induced obesity is a major contributor to the global pandemic of type 2 diabetes mellitus. The reduced ability of muscle tissue to regulate glucose homeostasis plays a major role in the development and prognosis of type 2 diabetes. In this study, an animal model of diet-induced obesity was used to elucidate changes in skeletal muscle insulin signaling in obesity-induced diabetes.

METHODS

Adult male Wistar rats were randomized and assigned to either a control group or to a test group. Controls were fed a standard laboratory pellet diet (chow-fed), while the test group had free access to a highly palatable diet (diet-fed). After 8 weeks, the diet-fed animals were subdivided into three subgroups and their diets were altered as follows: diet-to-chow, diet-fed with addition of fenofibrate given by oral gavage for a further 7 weeks, or diet-fed with vehicle given by oral gavage for a further 7 weeks, respectively.

RESULTS

Untreated diet-fed animals had a significantly higher body weight and metabolic profile than the control chow-fed animals. Intramuscular triacylglyceride levels in the untreated obese animals were significantly higher than those in the control chow-fed group. Expression of protein kinase C beta, phosphatidylinositol 3, Shc, insulin receptor substrate 1, ERK1/2, and endothelial nitric oxide synthase was significantly increased by dietary obesity, while that of insulin receptor beta, insulin receptor substrate 1, and protein kinase B (Akt) were not affected by obesity.

CONCLUSION

These data suggest that diet-induced obesity affects insulin signaling mechanisms, leading to insulin resistance in muscle.

Epicardial perivascular adipose tissue as a therapeutic target in obesity-related coronary artery disease

Adipose tissue is an active endocrine and paracrine organ that may influence the development of atherosclerosis and vascular disease. In the setting of obesity, adipose tissue produces a variety of inflammatory cytokines (or adipokines) that are known to modulate key mechanisms of atherogenesis. In particular, adipose tissue located on the surface of the heart surrounding large coronary arteries (i.e. epicardial perivascular adipose tissue) has been implicated in the pathogenesis of coronary artery disease. The present review outlines our current understanding of the cellular and molecular links between perivascular adipose tissue and atherosclerosis with a focus on potential mechanisms by which epicardial perivascular adipose tissue contributes to obesity-related coronary disease. The pathophysiology of perivascular adipose tissue in obesity and its influence on oxidative stress, inflammation, endothelial dysfunction and vascular reactivity is addressed. In addition, the contribution of specific epicardial perivascular adipose-derived adipokines (e.g. leptin, adiponectin) to the initiation and expansion of coronary disease is also highlighted. Finally, future investigative goals are discussed with an emphasis on indentifying novel therapeutic targets and disease markers within perivascular adipose tissue.

LINKED ARTICLES

This article is part of a themed section on Fat and Vascular Responsiveness. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-3.

Macronutrient composition and increased physical activity modulate plasma adipokines and appetite hormones during a weight loss intervention

BACKGROUND

We have shown previously that in overweight premenopausal women, changes in macronutrient composition and increasing the number of steps walked per day favorably affect body composition and plasma lipid profiles. As a follow-up, we evaluated the effect of moderate carbohydrate intake and increased physical activity on inflammation and regulation of appetite.

METHODS

Seventy premenopausal women with a body mass index (BMI) between 25 and 37 kg/m(2) participated in a 10-week weight loss intervention program consisting of the following macronutrient energy distribution: 40% carbohydrate, 30% fat, and 30% protein, in addition to a progressive increase in the number of steps taken per day. Plasma adiponectin, intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), leptin, and ghrelin levels were assessed at baseline and after 10 weeks.

RESULTS

Subjects reduced body weight by 4.5%, waist circumference (WC) by 6.4%, and trunk fat by 4.6%. Plasma insulin and insulin resistance assessed by homeostasis model assessment (HOMA) were reduced after 10 weeks (p < 0.01). Plasma adiponectin was increased by 11% (p < 0.05), and ICAM-1 levels were decreased (p < 0.05) after 10 weeks. A negative correlation was found between changes in insulin and changes in adiponectin between baseline and 10 weeks (r = -0.397, p < 0.01), indicating a role of adiponectin in increasing insulin sensitivity. In addition, plasma ghrelin levels were increased by 17% (p < 0.001), indicating a signal for increased appetite associated with weight loss.

CONCLUSIONS

These studies indicate that weight loss interventions involving moderate changes in dietary carbohydrate and increases in physical activity favorably affect insulin sensitivity and decrease inflammation.