Effects of weight reduction on obesity. Studies of lipid and carbohydrate metabolism in normal and hyperlipoproteinemic subjects

The glucose tolerance peak parameter revisited. Definition for a novel use in Gestational Diabetes Mellitus confirmation

Aims

This study aimed to establish a decisive threshold for the Glucose Tolerance peak (GTp) parameter in diagnosing Gestational Diabetes Mellitus (GDM) and to assess its diagnostic efficacy in comparison with other commonly employed indexes in clinical practice.

Materials and methods

Conducted as a prospective observational cohort, the study enrolled 92 pregnant women between 24-28 weeks of gestation, who underwent an Oral glucose Tolerance Test (OGTT) 100 gr. following a positive O'Sullivan screening at La Paz University Hospital. An additional 30-min sample was incorporated to assess the insulin response dynamics during hyperglycaemia. Basal indices and those derived from the OGTT 100 gr. test were computed. Receiver Operating Characteristic (ROC) curves were utilized to determine the optimal cut-off points for the indexes derived from the OGTT. Informed written consent was obtained from all participants.

Results

Significantly greater glucose tolerance, as indicated by GTp, was observed in the Non-Gestational Diabetes (NTG) pregnant group (p < 0.01). The GTp emerged as the parameter with the highest positive predictive value for GDM diagnosis. A cut-off of < 0.36 demonstrated 100% specificity and 75% sensitivity in diagnosing GDM.

Conclusions

GTp, an index derived exclusively from the OGTT peak glycaemia, proves valuable in confirming the presence of GDM. The GTp could be used to confirm the presence of GDM under necessity of a second OGTT as test confirmation in pregnant woman. A cut-off of < 0. 36 has a specificity of 100% and a sensitivity of 75% for the diagnosis of GDM.

Dietary intervention reprograms bone marrow cellular signaling in obese mice

Objectives

The current study aimed to investigate the pathogenesis of obesity-induced impaired bone mass accrual and the impact of dietary intervention on bone density in the mouse model of obesity.

Methods

Mice were fed with chow diet (CD) for 10 months, high-fat-diet (HFD) for 10 months, or HFD for 6 months then transferred to chow diet for 4 months (HFDt).

Results

Weight loss and decreased intrahepatic lipid accumulation were observed in mice following dietary intervention. Additionally, HFD feeding induced bone mass accrual, while diet intervention restrained trabecular bone density. These changes were further reflected by increased osteogenesis and decreased adipogenesis in HFDt mice compared to HFD mice. Furthermore, HFD feeding decreased the activity of the Wingless-related integration site (Wnt)-β-Catenin signaling pathway, while the Wnt signaling was augmented by diet intervention in the HFDt group.

Conclusions

Our findings suggest that a HFD inhibits bone formation and that dietary intervention reverses this inhibition. Furthermore, the dietary intervention was able to compensate for the suppressed increase in bone mass to a level comparable to that in the CD group. Our study suggests that targeting the Wnt signaling pathway may be a potential approach to treat obesity-induced impaired bone mass accrual.

Nutrition interventions for adults with dyslipidemia: A Clinical Perspective from the National Lipid Association

Lifestyle habits can have a profound impact on atherosclerotic cardiovascular disease (ASCVD) risk. The National Lipid Association previously published recommendations for lifestyle therapies to manage dyslipidemia. This Clinical Perspective provides an update with a focus on nutrition interventions for the three most common dyslipidemias in adults: 1) low-density lipoprotein cholesterol (LDL-C) elevation; 2) triglyceride (TG) elevation, including severe hypertriglyceridemia with chylomicronemia; and 3) combined dyslipidemia, with elevations in both LDL-C and TG levels. Lowering LDL-C and non-high-density lipoprotein cholesterol are the primary objectives for reducing ASCVD risk. With severe TG elevation (≥500 mg/dL), the primary objective is to prevent pancreatitis and ASCVD risk reduction is secondary. Nutrition interventions that lower LDL-C levels include reducing cholesterol-raising fatty acids and dietary cholesterol, as well as increasing intakes of unsaturated fatty acids, plant proteins, viscous fibers, and reducing adiposity for patients with overweight or obesity. Selected dietary supplements may be employed as dietary adjuncts. Nutrition interventions for all patients with elevated TG levels include restricting intakes of alcohol, added sugars, and refined starches. Additional lifestyle factors that reduce TG levels are participating in daily physical activity and reducing adiposity in patients with overweight or obesity. For patients with severe hypertriglyceridemia, an individualized approach is essential. Nutrition interventions for addressing concurrent elevations in LDL-C and TG include a combination of the strategies described for lowering LDL-C and TG. A multidisciplinary approach is recommended to facilitate success in making and sustaining dietary changes and the assistance of a registered dietitian nutritionist is highly recommended.

Past history of obesity triggers persistent epigenetic changes in innate immunity and exacerbates neuroinflammation

Age-related macular degeneration is a prevalent neuroinflammatory condition and a major cause of blindness driven by genetic and environmental factors such as obesity. In diseases of aging, modifiable factors can be compounded over the life span. We report that diet-induced obesity earlier in life triggers persistent reprogramming of the innate immune system, lasting long after normalization of metabolic abnormalities. Stearic acid, acting through Toll-like receptor 4 (TLR4), is sufficient to remodel chromatin landscapes and selectively enhance accessibility at binding sites for activator protein-1 (AP-1). Myeloid cells show less oxidative phosphorylation and shift to glycolysis, ultimately leading to proinflammatory cytokine transcription, aggravation of pathological retinal angiogenesis, and neuronal degeneration associated with loss of visual function. Thus, a past history of obesity reprograms mononuclear phagocytes and predisposes to neuroinflammation.

Lipid dysfunction and adrenomedullin expression in omental versus subcutaneous adipose tissues in diabetic pregnancies

Gestational diabetes mellitus (GDM) is one of the most common complications of pregnancy but the underlying mechanism remains obscure. The aims of this study are to examine if omental adipose tissue (OMAT) and subcutaneous AT (SCAT) differentially express proinflammatory and lipid metabolic adipokines, and if so, whether their regional differences have implications on lipid metabolism in GDM. Paired samples of OMAT and SCAT were excised from pregnant women in scheduled Cesarean sections with non-obese (NOBS), obese (OBS) and GDM. The results showed that the mRNA of monocyte chemoattractant protein (MCP)-1, macrophage marker CD68, and cytokines IL-6, IL-8, and TNF-α are increased in OMAT from GDM women compared to that in NOBS and OBS women (P<0.05). Glucose and TNF-α dose-dependently enhanced ADM and its receptor components CRLR and RAMPs in human adipocytes. Immunofluorescence showed that ADM and its receptor components are higher in OMAT from GDM women compared to non-GDM women. Further, basal lipolysis was greater in OMAT than in SCAT and ADM stimulates further glycerol release in OMAT, but not in SCAT, and these increases are reduced by ADM antagonist, ADM22-52. We therefore conclude that elevated ADM and its receptor expressions by OMAT, but not by SCAT appear to contribute to the lipid dysregulation in GDM women, and manipulation of ADM may represent one of the novel approaches in minimizing the risk of GDM-related fetal overgrowth.

Alleviation of diabetes mellitus through the restoration of β-cell function and lipid metabolism by Aloe vera (L.) Burm. f. extract in obesogenic WNIN/GR-Ob rats

ETHNOPHARMACOLOGICAL RELEVANCE

Aloe vera (L.) Burm. f. extract has been medicinally used for over 5000 years in different cultures for its curative and therapeutic properties ranging from dermatitis to diabetes. It has been demonstrated to alleviate diabetes through its protective effects on pancreatic islets and by improving insulin secretion.

AIM OF THE STUDY

To investigate the simultaneous effect of ethanolic A. vera gel extract on diabetes and obesogenic milieu in Streptozotocin-induced WNIN/GR-Ob mutant obese rats.

MATERIALS AND METHODS

A total of 30 rats were grouped equally into WNIN/GR-Ob control (received water as a vehicle), WNIN/GR-Ob Diabetic rats (Streptozotocin-35 mg/kg bw), WNIN/GR-Ob Diabetic rats + Sitagliptin (10 mg/kg bw), WNIN/GR-Ob Diabetic rats + A. vera (300 mg/kg bw) and GR-Ob control + A. vera (300 mg/kg bw). After 4 weeks of treatment, fasting blood glucose, serum insulin, Homeostatic Model Assessment - Insulin Resistance and β-cell function, glucose-stimulated insulin secretion, Dipeptidyl peptidase-IV activity, and lipid profiles were studied. In addition, ultrastructural analysis of isolated islets and dual-energy X-ray absorptiometry analysis for body composition were also carried out.

RESULTS

The A. vera treated group showed a significant reduction (p < 0.05) in triglyceride, Very low-density lipoprotein levels, Triglyceride to High-density lipoprotein ratio as well as fasting blood glucose levels and DPP-IV activity with a concomitant increase in the serum insulin levels. The increase in IR was observed in both WNIN/GR-Ob control and diabetic rats with a significant decrease in β-cell function in the diabetic rats as per Homeostatic Model Assessment values. Oral administration of A. vera was effective in both reducing Homeostatic Model Assessment-Insulin Resistance and increasing Homeostatic Model Assessment-β values. Also, the treated group demonstrated preservation of islets and a significant increase (p < 0.05) in the diameter of β-cell as evident through Scanning electron microscope analysis. The increase in lean body mass was manifested in the treated group with a reduction in Fat percent in comparison with other groups.

CONCLUSION

The beneficial effects of A. vera in WNIN/GR-Ob strain may be attributed to its ability to lower lipid profile thus improve insulin sensitivity and/or modulating β-cell function. Thus, it has great therapeutic potential as an herbal remedy for the treatment of diabetes and associated adverse effects such as obesity. The exact mechanism underlying the observation needs to be investigated further to explore the anti-obesity and anti-diabetic properties of A. vera and advocate its potential application as alternative medicine.

Interaction of quercetin and epigallocatechin gallate (EGCG) aggregates with pancreatic lipase under simplified intestinal conditions

Diets rich in flavonoids have been related with low obesity rates, which could be related with their potential to inhibit pancreatic lipase, the main enzyme of fat assimilation. Some flavonoids can aggregate in aqueous medium suggesting that the inhibition mechanism could occur on both molecular and colloidal levels. This study investigates the interaction of two flavonoid aggregates, quercetin and epigallocatechin gallate (EGCG), with pancreatic lipase under simplified intestinal conditions. The stability and the morphology of these flavonoid aggregates were studied in four different solutions: Control (water), salt, low lipase concentration and high lipase concentration. Particles were found by optical microscopy in almost all the solutions tested, except EGCG-control. The results show that the precipitation rate decreases for quercetin and increases for EGCG in salt solution and that lipase stabilize quercetin aggregates. In addition, both flavonoids were shown to precipitate together with pancreatic lipase resulting in a sequestering of the enzyme.

Alterations of Serum Ser312-Phosphorylated Fetuin-A from Exercise-Induced Moderate Body Weight Loss in Individuals with Obesity

OBJECTIVE

Phosphorylated fetuin-A (pFet-A) inhibits insulin action and has been shown to be associated with obesity and insulin resistance. The objective of this cohort study was to assess the effect of incremental body weight loss on alterations in serum pFet-A and indexes of insulin sensitivity.

METHODS

A total of 16 men with obesity attained a targeted weight loss of 8% to 10% of their initial body weight by achieving an energy expenditure/deficit of 2,000 to 2,500 kcal/wk. Anthropometric assessments and blood samples were obtained every 4 weeks. Weight loss was calculated and partitioned as 2% to 4%, 4% to 6%, 6% to 8%, and 8% to 10% compared with initial body weight.

RESULTS

Targeted body weight loss of 8% to 10% decreased serum pFet-A, pFet-A:Fet-A ratio, fasting insulin, log(homeostasis model assessment of insulin resistance), quantitative insulin sensitivity check index, adipose insulin resistance, and insulin resistance index significantly. Percent changes in serum pFet-A were associated with percent changes in indexes of insulin sensitivity. Unlike insulin sensitivity indexes, which were altered starting with 6% to 8% weight loss, serum pFet-A levels were significantly decreased by 19.6% starting with 2% to 4% weight loss and decreased by 25.6%, 36.8%, and 42.3% with 4% to 6%, 6% to 8%, and 8% to 10% weight loss, respectively.

CONCLUSIONS

This study reports for the first time that the insulin-sensitizing effects of moderate weight loss are associated with a reduction in serum pFet-A levels.

Observational Evidence for Unintentional Weight Loss in All-Cause Mortality and Major Cardiovascular Events: A Systematic Review and Meta-Analysis

The obesity paradox has been described in several observational cohorts and meta-analysis. However, evidence of the intentionality of weight loss in all-cause deaths and major cardiovascular events (MACE) in prospective cohorts is unclear. We analysed whether involuntary weight loss is associated with increased cardiovascular events and mortality. In a systematic review, we searched multiple electronic databases for observational studies published up to October 2016. Studies reporting risk estimates for unintentional weight loss compared with stable weight in MACE and mortality were included. Fifteen studies met the selection criteria, with a total of 178,644 participants. For unintentional weight loss, we found adjusted risk ratios (RRs) with confidence intervals (CIs) of 1.38 (95% CI: 1.23, 1.53) and 1.17 (95% CI: 0.98, 1.37) for all-cause mortality and MACE, respectively. Participants with comorbidities, overweight and obese populations, and older adults yielded RRs (95% CI) of 1.49 (1.30, 1.68), 1.11 (1.04, 1.18), and 1.81 (1.59, 2.03), respectively. Unintentional weight loss had a significant impact on all-cause mortality. We found no protective effect of being overweight or obese for unintentional weight loss and MACE.

ASSOCIATION OF PANCREAS VOLUME AND INSULIN RESISTANCE WITH ABDOMINAL FAT DISTRIBUTION IN TYPE-2 DIABETES AS EVALUATED BY COMPUTED TOMOGRAPHY

PURPOSE

We aimed to assess the relationship between the regional body fat distribution and insulin resistance and pancreas volume (PV) in type-2 diabetes (DM) patients.

METHODS

Fifty-three consecutive type-2 diabetic and 51 non-diabetic patients matched by age, gender and body mass index (BMI) were enrolled. Subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), waist circumference, and PV were measured with computed tomography. Insulin resistance was assessed by the homeostasis model assessment of insulin resistance (HOMA-IR).

RESULTS

Patients with type-2 DM had significantly lower PV than non-diabetic individuals. HOMA-IR ranged from 0.74 to 6.24; and from 0.37 to 3.26, in type-2 DM patients and non-diabetics, respectively. VAT was positively correlated with HOMA-IR in two groups. There were inverse correlations between PV and VAT and VAT/SAT but only in diabetics.

CONCLUSIONS

The VAT/SAT ratio may reflect the possible role of VAT to better understand the pathogenesis of obesity-related disorders in patients with type-2 DM.

Dissecting the relationship between obesity and hyperinsulinemia: Role of insulin secretion and insulin clearance

OBJECTIVE

The aim of this study was to better delineate the complex interrelationship among insulin resistance (IR), secretion rate (ISR), and clearance rate (ICR) to increase plasma insulin concentrations in obesity.

METHODS

Healthy volunteers (92 nondiabetic individuals) had an insulin suppression test to measure IR and graded-glucose infusion test to measure ISR and ICR. Obesity was defined as a body mass index (BMI) ≥30 kg/m² , and IR was defined as steady-state plasma glucose (SSPG) ≥10 mmol/L during the insulin suppression test. Plasma glucose and insulin concentrations, ISR, and ICR were compared in three groups: insulin sensitive/overweight; insulin sensitive/obesity; and insulin resistant/obesity.

RESULTS

Compared with the insulin-sensitive/overweight group, the insulin-sensitive/obesity had significantly higher insulin area under the curve (AUC) and ISR AUC during the graded-glucose infusion test (P < 0.001). Glucose AUC and ICR were similar. The insulin-resistant/obesity group had higher insulin AUC and ISR AUC compared with the insulin-sensitive/obesity but also had higher glucose AUC and decreased ICR (P < 0.01). In multivariate analysis, both BMI and SSPG were significantly associated with ISR.

CONCLUSIONS

Plasma insulin concentration and ISR are increased in individuals with obesity, irrespective of degree of IR, but a decrease in ICR is confined to the subset of individuals with IR.

A human model of dietary saturated fatty acid induced insulin resistance

BACKGROUND

Increased consumption of high-fat diets is associated with the development of insulin resistance and type 2 diabetes. Current models to study the mechanisms of high-fat diet-induced IR in humans are limited by their long duration or low efficacy. In the present study we developed and characterized an acute dietary model of saturated fatty acid-enriched diet induced insulin resistance.

METHODS

High caloric diets enriched with saturated fatty acids (SFA) or carbohydrates (CARB) were evaluated in subjects with normal and impaired glucose tolerance (NGT or IGT). Both diets were compared to a standard eucaloric American Heart Association (AHA) control diet in a series of crossover studies. Whole body insulin resistance was estimated as steady state plasma glucose (SSPG) concentrations during the last 30min of a 3-h insulin suppression test.

RESULTS

SSPG was increased after a 24-h SFA diet (by 83±74% vs. control, n=38) in the entire cohort, which was comprised of participants with NGT (92±82%, n=22) or IGT (65±55%, n=16) (all p<0.001). SSPG was also increased after a single SFA breakfast (55±32%, p=0.008, n=7). The increase in SSPG was less pronounced after an overnight fast following a daylong SFA diet (24±31%, p=0.04, n=10), and further attenuated 24h after returning to the control diet (19±35%, p=0.09, n=11). SSPG was not increased after a 24-h CARB diet (26±50%, p=0.11, n=12).

CONCLUSIONS

A short-term SFA-enriched diet induced whole body insulin resistance in both NGT and IGT subjects. Insulin resistance persisted overnight after the last SFA meal and was attenuated by one day of a healthy diet. This model offers opportunities for identifying early mechanisms and potential treatments of dietary saturated fat induced insulin resistance.

Physical activity and weight loss are independent predictors of improved insulin sensitivity following energy restriction

OBJECTIVE

The role of physical activity and the joint effect with sleep duration on insulin sensitivity (IS) during energy restriction followed by weight maintenance were determined.

METHODS

One hundred and two subjects (28 males) (mean ± SD age: 40 ± 9 years; BMI: 31.9 ± 3.0 kg/m(2) ) followed a very-low-energy diet for 8 weeks, followed by a 44-week period of weight maintenance. Body composition (three-compartment model based on body weight, total body water, and body volume), physical activity (accelerometry), sleep (questionnaire, Epworth Sleepiness Scale), and fasting plasma insulin and glucose concentrations were assessed before the diet and at 8, 20, and 52 weeks after the start.

RESULTS

Compared to baseline, IS was improved significantly after 8 weeks (P < 0.001) and was higher after 20 weeks (P < 0.001) and 52 weeks (P < 0.05). After 8, 20, and 52 weeks, 23% (P < 0.01), 19% (P < 0.05), and 13% (P < 0.05), respectively, of the variance in IS improvement was explained by weight loss percentage and change in physical activity counts.

CONCLUSIONS

Maintaining daily physical activity during energy restriction is as important as weight loss itself in the improvement of IS; there was no additional effect of change in sleep duration. During weight maintenance, improved IS is maintained better if physical activity returns to baseline or higher.

The Associations Between Increasing Degrees of HOMA-IR and Measurements of Adiposity Among Euglycemic U.S. Adults

BACKGROUND

The purpose of this study was to examine the associations between increasing degrees of insulin resistance (using the homeostatic model assessment of insulin resistance [HOMA-IR]) and two measures of adiposity in a nationally representative sample of euglycemic U.S. adults.

MATERIALS AND METHODS

Sample included adult participants (≥ 20 years of age) [N = 1586 (body mass index, BMI model), N = 1577 (waist circumference, WC model)] from the 1999-2004 National Health and Nutrition Examination Survey (NHANES). HOMA-IR was categorized into quartiles. BMI and WC were examined continuously as the dependent variables.

RESULTS

Following adjustment for covariates, those with HOMA-IR values in the second, third, and fourth quartiles had significantly higher BMIs (P < 0.001) compared with subjects in the first quartile. In the model using WC, significantly higher WCs were found in subjects in the second, third, and fourth quartiles of HOMA-IR (P < 0.001) compared with those in the first quartile. A significant moderate correlation was found between HOMA-IR and BMI (R(2) = 0.4171, P < 0.001), as well as HOMA-IR and WC (R(2) = 0.4826, P < 0.001).

CONCLUSIONS

Having a higher HOMA-IR value is associated with higher BMI and WC values in euglycemic subjects.

The effects of differing proportions of dietary macronutrients on the digestibility and post-prandial endocrine responses in domestic cats (Felis catus)

The aim of this study was to compare the effects of feeding two diets with different macronutrient proportions (high protein, low carbohydrate and low protein, high carbohydrate) on the digestibility and post-prandial endocrine responses of cats fed at maintenance levels, and to evaluate the effectiveness of the marginal ear vein prick technique for the measurement of blood glucose levels in feline studies. Two diets were fed to 16 adult domestic short-haired cats for a period of three weeks (eight cats per diet). Following a seven-day dietary adaptation period, the apparent macronutrient digestibility of the two diets was determined (days 8-19) using the total faecal collection method. The faeces were freeze dried, ground and analysed for dry matter, crude protein, crude fat and gross energy and then apparent digestibility was calculated. On days 20 and 21, the post-prandial glucose responses of the cats fed a single meal of one of the two diets were measured in serial blood samples collected using the marginal ear vein prick technique.

Results showed that the high protein, low carbohydrate diet had higher (p < 0.05) apparent digestibility of dry matter, crude protein, crude fat and energy, lower (p < 0.01) daily faecal output and smaller fluctuations in blood glucose concentrations. Despite the two groups of cats having similar calorific intakes, the cats fed the high protein diet lost weight over the study period, whereas those fed the high carbohydrate, low protein diet gained weight. The marginal ear vein prick technique proved to be an effective alternative to catheterisation for blood glucose determination. The high protein diet tested in the current study, in addition to being more aligned to the cat's natural carnivorous diet, may be beneficial for weight management and blood glucose control in cats.

Nox2 mediates skeletal muscle insulin resistance induced by a high fat diet

Inflammation and oxidative stress through the production of reactive oxygen species (ROS) are consistently associated with metabolic syndrome/type 2 diabetes. Although the role of Nox2, a major ROS-generating enzyme, is well described in host defense and inflammation, little is known about its potential role in insulin resistance in skeletal muscle. Insulin resistance induced by a high fat diet was mitigated in Nox2-null mice compared with wild-type mice after 3 or 9 months on the diet. High fat feeding increased Nox2 expression, superoxide production, and impaired insulin signaling in skeletal muscle tissue of wild-type mice but not in Nox2-null mice. Exposure of C2C12 cultured myotubes to either high glucose concentration, palmitate, or H2O2 decreases insulin-induced Akt phosphorylation and glucose uptake. Pretreatment with catalase abrogated these effects, indicating a key role for H2O2 in mediating insulin resistance. Down-regulation of Nox2 in C2C12 cells by shRNA prevented insulin resistance induced by high glucose or palmitate but not H2O2. These data indicate that increased production of ROS in insulin resistance induced by high glucose in skeletal muscle cells is a consequence of Nox2 activation. This is the first report to show that Nox2 is a key mediator of insulin resistance in skeletal muscle.

Effect of liraglutide administration and a calorie-restricted diet on lipoprotein profile in overweight/obese persons with prediabetes

BACKGROUND AND AIMS

To evaluate the effects of 14 weeks of liraglutide plus modest caloric restriction on lipid/lipoprotein metabolism in overweight/obese persons with prediabetes.

METHODS AND RESULTS

Volunteers with prediabetes followed a calorie-restricted diet (-500 Kcal/day) plus liraglutide (n = 23) or placebo (n = 27) for 14 weeks. The groups were similar in age (58 ± 7 vs. 58 ± 8 years) and body mass index (31.9 ± 2.8 vs. 31.9 ± 3.5 kg/m(2)). A comprehensive lipid/lipoprotein profile was obtained before and after intervention using vertical auto profile (VAP). Weight loss was greater in the liraglutide group than in the placebo group (6.9 vs. 3.3 kg, p < 0.001), as was the fall in fasting plasma glucose concentration (9.9 mg/dL vs. 0.3 mg/dL, p < 0.001). VAP analysis revealed multiple improvements in lipid/lipoprotein metabolism in liraglutide-treated compared with placebo-treated volunteers, including decreases in concentrations of total cholesterol, low-density lipoprotein cholesterol and several of its subclasses, triglyceride, and non-high-density cholesterol. The liraglutide-treated group also had a significant shift away from small, dense low-density lipoprotein-particles, as well as decreases in apolipoprotein B concentration and ratio of apolipoprotein B/apolipoprotein A-1. There were no significant changes in the lipoprotein profile in the placebo-treated group.

CONCLUSION

Treatment with liraglutide plus modest calorie restriction led to enhanced weight loss, a decrease in fasting plasma glucose concentration, and improvement in multiple aspects of lipid/lipoprotein metabolism associated with increased cardiovascular disease (CVD) risk. The significant clinical benefit associated with liraglutide-assisted weight loss in a group at high risk for CVD - obese/overweight individuals with prediabetes - as seen in our pilot study, suggests that this approach deserves further study.

Autonomic blockade improves insulin sensitivity in obese subjects

Obesity is an important risk factor for the development of insulin resistance. Initial compensatory mechanisms include an increase in insulin levels, which are thought to induce sympathetic activation in an attempt to restore energy balance. We have previously shown, however, that sympathetic activity has no beneficial effect on resting energy expenditure in obesity. On the contrary, we hypothesize that sympathetic activation contributes to insulin resistance. To test this hypothesis, we determined insulin sensitivity using a standard hyperinsulinemic euglycemic clamp protocol in obese subjects randomly assigned in a crossover design 1 month apart to receive saline (intact day) or trimetaphan (4 mg/min IV, autonomic blocked day). Whole-body glucose uptake (MBW in mg/kg per minute) was used as index of maximal muscle glucose use. During autonomic blockade, we clamped blood pressure with a concomitant titrated intravenous infusion of the nitric oxide synthase inhibitor N-monomethyl-L-arginine. Of the 21 obese subjects (43±2 years; 35±2 kg/m(2) body mass index) studied, 14 were insulin resistant; they were more obese, had higher plasma glucose and insulin, and had higher muscle sympathetic nerve activity (23.3±1.5 versus 17.2±2.1 burst/min; P=0.03) when compared with insulin-sensitive subjects. Glucose use improved during autonomic blockade in insulin-resistant subjects (MBW 3.8±0.3 blocked versus 3.1±0.3 mg/kg per minute intact; P=0.025), with no effect in the insulin-sensitive group. These findings support the concept that sympathetic activation contributes to insulin resistance in obesity and may result in a feedback loop whereby the compensatory increase in insulin levels contributes to greater sympathetic activation.

Hyperglycemia, assessed according to HbA1c , and future risk of venous thromboembolism: the Tromsø study

BACKGROUND

HbA1c , a marker of average plasma glucose level during the previous 8-12 weeks, is associated with the future risk of cardiovascular disease and all-cause mortality.

OBJECTIVES

To examine the association between hyperglycemia, assessed according to HbA1c , and the future risk of venous thromboembolism (VTE) in a population-based cohort.

METHODS

HbA1c was measured in 16 156 unique subjects (25-87 years) who participated in one or more surveys of the Tromsø study (Tromsø 4, 1994-1995; Tromsø 5, 2001-2002; and Tromsø 6, 2007-2008). All subjects were followed, and incident VTE events were recorded up to 31 December 2010.

RESULTS

There were 333 validated first VTE events, of which 137 were unprovoked, during a median follow-up of 7.1 years. HbA1c was not associated with the future risk of VTE in analyses treating HbA1c as a continuous variable, or in categorized analyses. The risk of VTE increased by 5% per one standard deviation (0.7%) increase in HbA1c (multivariable-adjusted hazard ratio [HR] 1.05; 95% confidence interval [CI] 0.97-1.14), and subjects with HbA1c  ≥ 6.5% had a 27% higher risk than those with HbA1c  < 5.7% (multivariable-adjusted HR 1.27; 95% CI 0.72-2.26). There was no significant linear trend for an increased risk of VTE across categories of HbA1c (P = 0.27).

CONCLUSIONS

Serum levels of HbA1c were not associated with the future risk of VTE in multivariable analysis. Our findings suggest that hyperglycemia does not play an important role in the pathogenesis of VTE.

The effects of co-administration of probiotics with herbal medicine on obesity, metabolic endotoxemia and dysbiosis: a randomized double-blind controlled clinical trial

BACKGROUND & AIMS

Probiotics help maintain balance in composition of the gut microbiota, and have been considered as a potential treatment for obesity. This study was conducted in order to assess the effects of probiotics when combined with herbal medicine in treatment of obesity. Probiotics were tested for the ability to modulate gut microbiota, gut permeability, and endotoxin level, which may have correlation with factors involved in obesity.

METHODS

A randomized, double-blind, placebo controlled study was conducted, in which patients with higher BMI (>25 kg/m(2)) and waist circumference (>85 cm) were enrolled and randomly assigned to receive Bofutsushosan with either probiotics or placebo capsules for a period of eight weeks. Assessment of body composition parameters, metabolic biomarkers, endotoxin level, gut permeability, and fecal bacteria in stool was performed at baseline and at week 8. The study was registered at the Clinical Research Information Service, approved by the Korea National Institute of Health (KCT0000386).

RESULTS

Although both groups showed a significant reduction in weight and waist circumference (p = 0.000), no significant differences in body composition and metabolic markers were observed. In correlation analysis, change in body composition showed positive correlation with endotoxin level (r = 0.441, p < 0.05 for BW; and r = 0.350, p < 0.05 for fat mass) and the population of gut Lactobacillus plantarum (r = 0.425, p < 0.05 for BW; and r = 0.407, p < 0.05 for BMI). The Gram negative bacterial population in gut also exhibited positive correlation with changes in body composition (WC) and total cholesterol level (r = 0.359, and 0.393, for the former and later parameters, respectively, p < 0.05 for both). While, the profile of gut Bifidobacterium breve population showed negative correlation with endotoxin level (r = -0.350, p < 0.05).

CONCLUSIONS

Correlations between gut microbiota and change in body composition indicate that probiotics may influence energy metabolism in obesity. Correlation between endotoxin level and weight reduction indicates that probiotics may play an important role in prevention of endotoxin production, which can lead to gut microbiota dysbiosis associated with obesity.

Glutathione peroxidase activity in obese and nonobese diabetic patients and role of hyperglycemia in oxidative stress

Background:

Both hyperglycemia and obesity are known to cause oxidative stress, which leads to many complications associated with diabetes mellitus. A large number of diabetic patients are obese. Glutathione peroxidase (GPx) is an important indicator of level of oxidative stress.

Materials and Methods:

In the present study, we assessed GPx levels in 20 healthy controls, obese, and nonobese diabetic patients (n=20 each) and analyzed the effect of insulin treatment for 24 and 48 weeks on GPx activity. GPx activity was measured using biochemical method. The GPx activity was also correlated with glycemic status of obese and nonobese diabetic patients [fasting plasma glucose (FPG) levels] after insulin therapy. Statplus software was used for statistical analysis.

Results:

We found that there is suppression of GPx activity in diabetic patients as compared to healthy controls (70.9 ± 9.6 U/mg protein) and suppression is more in case of obese (23.4 ± 3.8 U/mg protein) than nonobese diabetics (41.5 ± 3.5 U/mg protein). Both obese (26.05 ± 4.03 U/mg protein) and nonobese (48.7 ± 4.8 U/mg protein) diabetics had increase in GPx activity after 24 weeks of insulin treatment. Further, insulin treatment led to improvement in oxidative stress after 48 weeks in both obese (28.4 ± 6.4) as well as nonobese diabetics (51.8 ± 5.4). The nonobese group showed extremely significant (P<0.001) increase in GPx activity after 24 and 48 weeks both, while obese group showed significant (P value<0.05) increase in GPx activity with insulin treatment only after 48 weeks. A negative correlation was found between postinsulin GPx levels and FPG of obese and nonobese diabetics. The correlation was more strong in case of nonobese than obese diabetics.

Conclusion:

Higher levels of oxidative stress in obese diabetics even after control of hyperglycemia by insulin treatment reflect the importance of obesity in contributing to oxidative stress.

Insulin resistance as a predictor of gains in body fat, weight, and abdominal fat in nondiabetic women: a prospective study

The purpose was to determine the relationship between insulin resistance (IR) and risk of gaining body fat percentage (BF%), body weight, and abdominal fat over 18 months. A prospective cohort study was conducted using a sample of 226 women. IR was assessed using fasting blood insulin and glucose levels to calculate homeostatic model assessment (HOMA). Participants were divided into High (4th quartile) Moderate (2nd and 3rd quartiles), and Low (1st quartile) HOMA categories. BF% was estimated using plethysmography (Bod Pod), weight was measured in a standard swimsuit, and abdominal fat was indexed using the average of two circumferences taken at the umbilicus. Participants wore accelerometers and completed weighed food logs for 7 consecutive days to control for the effect of physical activity (PA) and energy intake, respectively. On average, women in the High HOMA group decreased in BF% (-0.48 ± 3.60), whereas those in the Moderate (0.40 ± 3.66) and Low HOMA (1.17 ± 3.15) groups gained BF% (F = 5.4, P = 0.0211). Changes in body weight showed a similar dose-response relationship (F = 4.7, P = 0.0317). However, baseline IR was not predictive of changes in abdominal fat (F = 0.8, P = 0.3635). Controlling for several covariates had little effect on gains in BF% and weight, but adjusting for initial BF% and/or initial weight nullified changes in BF% and weight across the IR groups. In conclusion, women with High HOMA tend to gain significantly less BF% and weight than women with low or moderate HOMA. The decreased risk appears unrelated to several covariates, except initial BF% and weight levels, which seem to play key roles in the relationships.

Use of a two-stage insulin infusion study to assess the relationship between insulin suppression of lipolysis and insulin-mediated glucose uptake in overweight/obese, nondiabetic women

Differences in insulin regulation of free fatty acids (FFAs) are not readily apparent at the same insulin concentrations used to differentiate relative insulin-mediated glucose disposal. Resistance to insulin-mediated glucose disposal and higher daylong FFA concentrations occur more commonly in obese individuals. However, the relationship between the ability of insulin to suppress FFA release from adipose tissue and stimulate glucose disposal in muscle has not been clearly defined in this population. The current study was initiated to test the hypothesis that these 2 facets of insulin action are related, with greater defects in insulin-mediated glucose disposal associated with less effective insulin inhibition of FFA release from adipose tissue. Subjects included 56 healthy nondiabetic overweight/moderately obese women classified as insulin resistant or insulin sensitive based on whole-body glucose disposal. All underwent a modified 240-minute 2-stage insulin infusion with basal (∼15 µU/mL) and physiologically elevated (∼80 µU/mL) steady-state insulin concentrations. Plasma glucose, insulin, FFA, and glycerol were measured throughout. Whereas plasma glucose differed most during physiological hyperinsulinemia in insulin-resistant vs insulin-sensitive subjects, plasma FFA/glycerol differed most during basal insulin concentrations. The FFA concentrations during the basal insulin steady state correlated highly (r = 0.85, P < .001) with glucose concentrations during the hyperinsulinemic steady state. Overweight/moderately obese women exhibit dramatic differences in the ability of insulin to suppress plasma FFA, which correlate highly with differences in insulin-mediated glucose disposal. Variability in insulin regulation of FFA is most apparent at basal insulin concentrations, whereas differences in glucose disposal are most apparent during physiologic hyperinsulinemia. Both can be quantified using a simple 2-stage insulin infusion study, with first-stage FFA concentrations and second-stage glucose concentrations being most informative.

Time perspective and weight management behaviors in newly diagnosed Type 2 diabetes: a mediational analysis

The primary objective of the current study was to examine the extent to which domain-specific time perspective predicts weight management behaviors (dietary behavior and physical activity) among those newly diagnosed with Type 2 diabetes. A secondary objective was to test potential mediators of the hypothesized effect (behavioral intention, self-efficacy and control beliefs). A total of 204 adults newly diagnosed (≤6 months) with Type 2 diabetes participated in the study, which included a baseline assessment of domain-general and domain-specific time perspective, as well as strength of intention to perform two weight-management behaviors (dietary choice and physical activity); both weight-management behaviors were assessed again at 6 month follow-up. Hierarchical multiple regression analyses revealed a prospective association between domain-specific time perspective and uptake of weight management behaviors. Individuals with newly diagnosed T2DM possessing a future-oriented time perspective reported making less frequent fatty food choices and greater increases in physical activity over the 6-month follow-up interval. These effects were selectively mediated by intention strength, and not competing social cognitive variables. For both behaviors, the total effects and meditational models were robust to adjustments for demographics, body composition and disease variables. A future-oriented time perspective is prospectively associated with superior uptake of weight management behaviors among those with newly diagnosed Type 2 diabetes. The facilitating effect of future-oriented thinking appears to occur via enhanced strength of intentions to perform weight management behaviors.

Preferential fat deposition in subcutaneous versus visceral depots is associated with insulin sensitivity

BACKGROUND

Studies on the relationship between regional fat and insulin resistance yield mixed results. Our objective was to determine whether regional fat distribution, independent of obesity, is associated with insulin resistance.

DESIGN

Subjects included 115 healthy, overweight/moderately obese adults with body mass index (BMI) 25-36.9 kg/m(2) who met predetermined criteria for being insulin resistant (IR) or insulin sensitive (IS) based on the modified insulin suppression test. Computerized tomography was used to quantify visceral adipose tissue (VAT), sc adipose tissue (SAT), and thigh adipose tissue. Fat mass in each depot was compared according to IR/IS group, adjusting for BMI and sex.

RESULTS

Despite nearly identical mean BMI in the IR vs. IS groups, VAT and %VAT were significantly higher in the IR group, whereas SAT, %SAT, and thigh sc fat were significantly lower. In logistic regression analysis, each sd increase in VAT increased the odds of being IR by 80%, whereas each increase in SAT decreased the odds by 48%; each increase in thigh fat decreased the odds by 59% and retained significance after adjusting for other depots. When grouped by VAT tertile, IS vs. IR individuals had significantly more SAT. There was no statistically significant interaction between sex and these relationships.

CONCLUSION

These data demonstrate that after adjustment for BMI and VAT mass, sc abdominal and thigh fat are protective for insulin resistance, whereas VAT, after adjustment for SAT and BMI, has the opposite effect. Whether causal in nature or a marker of underlying pathology, these results clarify that regional distribution of fat-favoring sc depots is associated with lower risk for insulin resistance.

Insulin resistance: the link between obesity and cardiovascular disease

There seems to be general agreement that the prevalence of obesity is increasing in the United States and that we are in the midst of an obesity epidemic. The disease-related implications of this epidemic have received an enormous amount of publicity in the popular media, but public awareness of the untoward effects of excess weight has not led to an effective approach to dealing with the dilemma. The gravity of the problem is accentuated in light of the report that only approximately 50% of physicians polled provided weight loss counseling. Given the importance of excess adiposity as increasing the risk of CVD, 2DM, and hypertension and the combination of an increase in the prevalence of overweight/obesity and a health care system unprepared to deal with this situation, it is essential that considerable thought be given as to how to best address this dilemma. In this context, it must be emphasized that CVD, 2DM, and hypertension are characterized by resistance to insulin-mediated glucose disposal and that insulin resistance and the compensatory hyperinsulinemia associated with insulin resistance have been shown to be independent predictors of all three clinical syndromes. It has also been apparent for many years that overweight/obese individuals tend to be insulin resistant and become more insulin sensitive with weight loss.25 In light of these observations, it seems reasonable to suggest that insulin resistance is the link between overweight/obesity and the adverse clinical syndromes related to excess adiposity. The evidence summarized in this review shows that the more overweight an individual, the more likely he or she is insulin resistant and at increased risk to develop all the abnormalities associated with this defect in insulin action. Not all overweight/obese individuals are insulin resistant, however, any more than all insulin resistant individuals are overweight/obese. More important, there is compelling evidence that CVD risk factors are present to a significantly greater degree in the subset of overweight/obese individuals that is also insulin resistant. Not surprisingly,we have also demonstrated that an improvement in CVD risk factors with weight loss occurs to a significantly greater degree in those overweight/obese individuals who are also insulin resistant at baseline. In view of the ineffectiveness of current clinical approaches to weight loss, it seems necessary to recognize that not all overweight/obese individuals are at equal risk to develop CVD and that it is clinically useful to identify those at highest risk. The simplest way to achieve this task seems to be focusing on the CVD risk factors that are highly associated with insulin resistance/hyperinsulinemia. If this is done, then intense efforts at weight control can be brought to bear on those who not only need it the most but also have the most to gain by losing weight.

Directive and nondirective e-coach support for weight loss in overweight adults

BACKGROUND

Although e-coach support increases the effectiveness of Internet weight loss interventions, no studies have assessed influence of type of e-coach support.

PURPOSE

The effects of nondirective (collaborative, flexible) and directive (prescriptive, protocol driven) e-coach support on weight loss, dietary behavior, physical activity, and engagement were assessed in a 12-week weight loss e-coaching program.

PROCEDURES

Overweight adults (N = 104) were randomly assigned to nondirective, directive, or minimal support. All received weekly lessons and feedback graphs via e-mail. Participants in the nondirective and directive support conditions received individualized nondirective or directive weight loss support.

RESULTS

For females, weight loss (η(2) = 0.10) and changes in waist circumference (η(2) = 0.07) were greater in the directive than in the nondirective and minimal support conditions.

CONCLUSIONS

Differences in type of e-coach support are salient to participants. Directive support is beneficial to females in a 12-week e-coach weight loss program.

Hepatic gene expression profiles are altered by dietary unsalted korean fermented soybean (chongkukjang) consumption in mice with diet-induced obesity

We found that Chongkukjang, traditional unsalted fermented soybean, has an antiobesity effect in mice with diet-induced obesity and examined the changes in hepatic transcriptional profiles using cDNA microarray. High-fat diet-induced obese C57BL/6J mice were divided into three groups: normal-diet control group (NDcon, 10% of total energy from fat), high-fat diet control group (HDcon, 45% of total energy from fat), and HDcon plus 40% Chongkukjang (HDC) and were fed for 9 weeks. The HDC group mice were pair-fed (isocalorie) with mice in the HDcon group. Final body weight, epididymal fat accumulation, serum total cholesterol, and LDL-cholesterol were improved in HDC group. The cDNA microarray analyses revealed marked alterations in the expression of about 800 genes. Several genes involved in fatty acid catabolism (Acaa2, Mgll, Phyh, Slc27a2, and Slc27a5) were normalized by Chongkukjang consumption. This study showed beneficial effects of Chongkukjang consumption in preventing diet-induced obesity and related metabolic abnormalities.

The metabolic syndrome: time to get off the merry-go-round?

The diagnostic category of the metabolic syndrome (MetS) has received considerable attention over the last decade, and prestigious organizations continue to strive for its incorporation into medical practice. This review has three goals: (i) summarize the history of the several attempts to define a diagnostic category designated as the MetS; (ii) question the aetiological role of abdominal obesity in the development of the other components of the MetS; and (iii) evaluate a diagnosis of the MetS as an effective way to identify apparently healthy individuals at increased risk to develop cardiovascular disease (CVD) or type 2 diabetes (2DM). The most important conclusion is that the MetS seems to be less effective in this population than the Framingham Risk Score in predicting CVD, and no better, if not worse, than fasting plasma glucose concentrations in predicting 2DM.

A healthy lifestyle intervention for middle-aged and older schizophrenia patients with diabetes mellitus: a 6-month follow-up analysis

The purpose of this study was to test the sustained impact of a 6-month diabetes management intervention in middle-aged and older adults with schizophrenia and type 2 diabetes mellitus.

METHOD

Fifty-two individuals, over the age of 40 completed both baseline and 12-month follow-up assessments.

RESULTS

At 12 months, Diabetes Awareness and Rehabilitation Training (DART) participants experienced significantly greater improvement in body mass index, waist circumference and diabetes knowledge than did the Usual Care Plus Information (UCI) group. No improvements were found for A1C or energy expenditure.

CONCLUSIONS

Results suggest that DART promotes lasting changes in health parameters that are maintained after treatment ends.

Decrease in hepatic very-low-density lipoprotein-triglyceride secretion after weight loss is inversely associated with changes in circulating leptin

AIM

Although weight loss usually decreases very-low-density lipoprotein-triglyceride (VLDL-TG) secretion rate, the change in VLDL-TG kinetics is not directly related to the change in body weight. Circulating leptin also declines with weight loss and can affect hepatic lipid metabolism. The aim of this study was to determine whether circulating leptin is associated with weight loss-induced changes in VLDL-TG secretion.

METHODS

Ten extremely obese subjects were studied. VLDL-TG secretion rate and the contribution of systemic (derived from lipolysis of subcutaneous adipose tissue TG) and non-systemic fatty acids (derived primarily from lipolysis of intrahepatic and intraperitoneal TG, and de novo lipogenesis) to VLDL-TG production were determined by using stable isotopically labelled tracer methods before and 1 year after gastric bypass surgery.

RESULTS

Subjects lost 33 +/- 12% of body weight, and VLDL-TG secretion rate decreased by 46 +/- 23% (p = 0.001), primarily because of a decrease in the secretion of VLDL-TG from non-systemic fatty acids (p = 0.002). Changes in VLDL-TG secretion rates were not significantly related to reductions in body weight, body mass index, plasma palmitate flux, free fatty acid or insulin concentrations. The change in VLDL-TG secretion was inversely correlated with the change in plasma leptin concentration (r = -0.72, p = 0.013), because of a negative association between changes in leptin and VLDL-TG secretion from non-systemic fatty acids (r = -0.95, p < 0.001).

CONCLUSIONS

Weight loss-induced changes in plasma leptin concentration are inversely associated with changes in VLDL-TG secretion rate. Additional studies are needed to determine whether the correlation between circulating leptin and VLDL-TG secretion represents a cause-and-effect relationship.

Using pre-existing microarray datasets to increase experimental power: application to insulin resistance

Although they have become a widely used experimental technique for identifying differentially expressed (DE) genes, DNA microarrays are notorious for generating noisy data. A common strategy for mitigating the effects of noise is to perform many experimental replicates. This approach is often costly and sometimes impossible given limited resources; thus, analytical methods are needed which increase accuracy at no additional cost. One inexpensive source of microarray replicates comes from prior work: to date, data from hundreds of thousands of microarray experiments are in the public domain. Although these data assay a wide range of conditions, they cannot be used directly to inform any particular experiment and are thus ignored by most DE gene methods. We present the SVD Augmented Gene expression Analysis Tool (SAGAT), a mathematically principled, data-driven approach for identifying DE genes. SAGAT increases the power of a microarray experiment by using observed coexpression relationships from publicly available microarray datasets to reduce uncertainty in individual genes' expression measurements. We tested the method on three well-replicated human microarray datasets and demonstrate that use of SAGAT increased effective sample sizes by as many as 2.72 arrays. We applied SAGAT to unpublished data from a microarray study investigating transcriptional responses to insulin resistance, resulting in a 50% increase in the number of significant genes detected. We evaluated 11 (58%) of these genes experimentally using qPCR, confirming the directions of expression change for all 11 and statistical significance for three. Use of SAGAT revealed coherent biological changes in three pathways: inflammation, differentiation, and fatty acid synthesis, furthering our molecular understanding of a type 2 diabetes risk factor. We envision SAGAT as a means to maximize the potential for biological discovery from subtle transcriptional responses, and we provide it as a freely available software package that is immediately applicable to any human microarray study.

Lack of suppression of circulating free fatty acids and hypercholesterolemia during weight loss on a high-fat, low-carbohydrate diet

BACKGROUND

Little is known about the comparative effect of weight-loss diets on metabolic profiles during dieting.

OBJECTIVE

The purpose of this study was to compare the effect of a low-carbohydrate diet (< or =20 g/d) with a high-carbohydrate diet (55% of total energy intake) on fasting and hourly metabolic variables during active weight loss.

DESIGN

Healthy, obese adults (n = 32; 22 women, 10 men) were randomly assigned to receive either a carbohydrate-restricted diet [High Fat; mean +/- SD body mass index (BMI; in kg/m(2)): 35.8 +/- 2.9] or a calorie-restricted, low-fat diet (High Carb; BMI: 36.7 +/- 4.6) for 6 wk. A 24-h in-patient feeding study was performed at baseline and after 6 wk. Glucose, insulin, free fatty acids (FFAs), and triglycerides were measured hourly during meals, at regimented times. Remnant lipoprotein cholesterol was measured every 4 h.

RESULTS

Patients lost a similar amount of weight in both groups (P = 0.57). There was an absence of any diet treatment effect between groups on fasting triglycerides or on remnant lipoprotein cholesterol, which was the main outcome. Fasting insulin decreased (P = 0.03), and both fasting (P = 0.040) and 24-h FFAs (P < 0.0001) increased within the High Fat group. Twenty-four-hour insulin decreased (P < 0.05 for both groups). Fasting LDL cholesterol decreased in the High Carb group only (P = 0.003). In both groups, the differences in fasting and 24-h FFAs at 6 wk were significantly correlated with the change in LDL cholesterol (fasting FFA: r = 0.41, P = 0.02; 24-h FFA: r = 0.52, P = 0.002).

CONCLUSIONS

Weight loss was similar between diets, but only the high-fat diet increased LDL-cholesterol concentrations. This effect was related to the lack of suppression of both fasting and 24-h FFAs.

Differential intra-abdominal adipose tissue profiling in obese, insulin-resistant women

BACKGROUND

We recently identified differences in abdominal subcutaneous adipose tissue (SAT) from insulin-resistant (IR) as compared to obesity-matched insulin sensitive individuals, including accumulation of small adipose cells, decreased expression of cell differentiation markers, and increased inflammatory activity. This study was initiated to see if these changes in SAT of IR individuals were present in omental visceral adipose tissue (VAT); in this instance, individuals were chosen to be IR but varied in degree of adiposity. We compared cell size distribution and genetic markers in SAT and VAT of IR individuals undergoing bariatric surgery.

METHODS

Eleven obese/morbidly obese women were IR by the insulin suppression test. Adipose tissue surgical samples were fixed in osmium tetroxide for cell size analysis via Beckman Coulter Multisizer. Quantitative real-time polymerase chain reaction for genes related to adipocyte differentiation and inflammation was performed.

RESULTS

While proportion of small cells and expression of adipocyte differentiation genes did not differ between depots, inflammatory genes were upregulated in VAT. Diameter of SAT large cells correlated highly with increasing proportion of small cells in both SAT and VAT (r = 0.85, p = 0.001; r = 0.72, p = 0.01, respectively). No associations were observed between VAT large cells and cell size variables in either depot. The effect of body mass index (BMI) on any variables in both depots was negligible.

CONCLUSIONS

The major differential property of VAT of IR women is increased inflammatory activity, independent of BMI. The association of SAT adipocyte hypertrophy with hyperplasia in both depots suggests a primary role SAT may have in regulating regional fat storage.

Genome-wide mRNA expression analysis of hepatic adaptation to high-fat diets reveals switch from an inflammatory to steatotic transcriptional program

BACKGROUND

Excessive exposure to dietary fats is an important factor in the initiation of obesity and metabolic syndrome associated pathologies. The cellular processes associated with the onset and progression of diet-induced metabolic syndrome are insufficiently understood.

PRINCIPAL FINDINGS

To identify the mechanisms underlying the pathological changes associated with short and long-term exposure to excess dietary fat, hepatic gene expression of ApoE3Leiden mice fed chow and two types of high-fat (HF) diets was monitored using microarrays during a 16-week period. A functional characterization of 1663 HF-responsive genes reveals perturbations in lipid, cholesterol and oxidative metabolism, immune and inflammatory responses and stress-related pathways. The major changes in gene expression take place during the early (day 3) and late (week 12) phases of HF feeding. This is also associated with characteristic opposite regulation of many HF-affected pathways between these two phases. The most prominent switch occurs in the expression of inflammatory/immune pathways (early activation, late repression) and lipogenic/adipogenic pathways (early repression, late activation). Transcriptional network analysis identifies NF-kappaB, NEMO, Akt, PPARgamma and SREBP1 as the key controllers of these processes and suggests that direct regulatory interactions between these factors may govern the transition from early (stressed, inflammatory) to late (pathological, steatotic) hepatic adaptation to HF feeding. This transition observed by hepatic gene expression analysis is confirmed by expression of inflammatory proteins in plasma and the late increase in hepatic triglyceride content. In addition, the genes most predictive of fat accumulation in liver during 16-week high-fat feeding period are uncovered by regression analysis of hepatic gene expression and triglyceride levels.

CONCLUSIONS

The transition from an inflammatory to a steatotic transcriptional program, possibly driven by the reciprocal activation of NF-kappaB and PPARgamma regulators, emerges as the principal signature of the hepatic adaptation to excess dietary fat. These findings may be of essential interest for devising new strategies aiming to prevent the progression of high-fat diet induced pathologies.

Gender differences in lipid metabolism and the effect of obesity

There are many differences between men and women, and between lean and obese subjects, in fatty acid and very low-density lipoprotein triglyceride and apolipoprotein B-100 metabolism. Currently, observations in this area are predominantly descriptive. The mechanisms responsible for sexual dimorphism in lipid metabolism are largely unknown.

Association between increased platelet P-selectin expression and obesity in patients with type 2 diabetes: a BARI 2D (Bypass Angioplasty Revascularization Investigation 2 Diabetes) substudy

OBJECTIVE

To determine whether obesity increases platelet reactivity and thrombin activity in patients with type 2 diabetes plus stable coronary artery disease.

RESEARCH DESIGN AND METHODS

We assessed platelet reactivity and markers of thrombin generation and activity in 193 patients from nine clinical sites of the Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D). Blood taken at the time of enrollment was used for assay of the concentration of prothrombin fragment 1.2 (PT1.2, released when prothrombin is activated) and fibrinopeptide A (FPA, released when fibrinogen is cleaved). Platelet activation was identified with the use of flow cytometry in response to 0, 0.2, and 1 micromol/l adenosine diphosphate (ADP).

RESULTS

Concentrations of FPA, PT1.2, and platelet activation in the absence of agonist were low. Greater BMI was associated with higher platelet reactivity in response to 1 microm ADP as assessed by surface expression of P-selectin (r = 0.29, P < 0.0001) but not reflected by the binding of fibrinogen to activated glycoprotein IIb-IIIa. BMI was not associated with concentrations of FPA or PT1.2. Platelet reactivity correlated negatively with A1C (P < 0.04), was not related to the concentration of triglycerides in blood, and did not correlate with the concentration of C-reactive peptide. CONCLUSIONS Among patients enrolled in this substudy of BARI 2D, a greater BMI was associated with higher platelet reactivity at the time of enrollment. Our results suggest that obesity and insulin resistance that accompanies obesity may influence platelet reactivity in patients with type 2 diabetes.

Serum inorganic phosphate in middle-aged men. I. Inverse relation to body weight

Serum inorganic phosphate was determined in 752 men born in 1926. An inverse correlation was found between serum inorganic phosphate levels and body weight. Other parameters of possible relevance to this finding, such as serum calcium, serum albumin, serum lambda-glutamyltransferase, and the occurrence of upper gastrointestinal disorders were analysed, and no correlations to the phosphate level were detected.

Three year's follow-up of members of a Swedish commercial weight-reducing club

The weight changes of 676 members of a commercial weight loosing club were analysed and a questionnaire was given to a subgroup of 150 participants. The median age at entry was 48 years. The Broca index (kg/cm - 100) ranged from 0.85 to 1.70. Only 15 males participated. The initiative to join the club came from the member herself in 59% of the cases; only 3% were referred by a physician. The drop-out frequency during an 8-week "Slim Club" course was 55%. Members who participated in more than 4 of the 8 weekly sessions had a mean weight loss of 6.2 kg (range 0.5 - 15). Members with higher initial weights lost more than those who were less overweight. The mean cost of each kg lost was about 40 Sw. cr./kg (approximately 9 US$). After 3 years, 367 members could be contacted for an interview. Their initial mean weight (+/- S. D.) was 76.1 +/- 9.8 kg. After the initial course the mean weight was 70.5 +/- 9.4 kg (p less than 0.001). Three years later the reported mean weight was 72.3 +/- 10.1 kg (p less than 0.001 versus initial weight). Thus even a short course may have significant long-term effects on weight loss. The weight-reducing club may therefore be a helpful tool in the treatment of overweight subjects.