Barbora de Courten

High-Density Lipoprotein Modulates Glucose Metabolism in Patients With Type 2 Diabetes Mellitus

Background— Low plasma high-density lipoprotein (HDL) is associated with elevated cardiovascular risk and aspects of the metabolic syndrome. We hypothesized that HDL modulates glucose metabolism via elevation of plasma insulin and through activation of the key metabolic regulatory enzyme, AMP-activated protein kinase, in skeletal muscle. Methods and Results— Thirteen patients with type 2 diabetes mellitus received both intravenous reconstituted HDL (rHDL: 80 mg/kg over 4 hours) and placebo on separate days in a double-blind, placebo-controlled crossover study. A greater fall in plasma glucose from baseline occurred during rHDL than during placebo (at 4 hours rHDL=−2.6±0.4; placebo=−2.1±0.3mmol/L; P=0.018). rHDL increased plasma insulin (at 4 hours rHDL=3.4±10.0; placebo= −19.2±7.4 pmol/L; P=0.034) and also the homeostasis model assessment &bgr;-cell function index (at 4 hours rHDL=18.9±5.9; placebo=8.6±4.4%; P=0.025). Acetyl-CoA carboxylase &bgr; phosphorylation in skeletal muscle biopsies was increased by 1.7±0.3-fold after rHDL, indicating activation of the AMP-activated protein kinase pathway. Both HDL and apolipoprotein AI increased glucose uptake (by 177±12% and 144±18%, respectively; P<0.05 for both) in primary human skeletal muscle cell cultures established from patients with type 2 diabetes mellitus (n=5). The mechanism is demonstrated to include stimulation of the ATP-binding cassette transporter A1 with subsequent activation of the calcium/calmodulin-dependent protein kinase kinase and the AMP-activated protein kinase pathway. Conclusions— rHDL reduced plasma glucose in patients with type 2 diabetes mellitus by increasing plasma insulin and activating AMP-activated protein kinase in skeletal muscle. These findings suggest a role for HDL-raising therapies beyond atherosclerosis to address type 2 diabetes mellitus.

Adipogenic Human Adenovirus Ad-36 Induces Commitment, Differentiation, and Lipid Accumulation in Human Adipose-Derived Stem Cells

Human adenovirus Ad‐36 is causatively and correlatively linked with animal and human obesity, respectively. Ad‐36 enhances differentiation of rodent preadipocytes, but its effect on adipogenesis in humans is unknown. To indirectly assess the role of Ad‐36‐induced adipogenesis in human obesity, the effect of the virus on commitment, differentiation, and lipid accumulation was investigated in vitro in primary human adipose‐derived stem/stromal cells (hASC). Ad‐36 infected hASC in a time‐ and dose‐dependent manner. Even in the presence of osteogenic media, Ad‐36‐infected hASC showed significantly greater lipid accumulation, suggestive of their commitment to the adipocyte lineage. Even in the absence of adipogenic inducers, Ad‐36 significantly increased hASC differentiation, as indicated by a time‐dependent expression of genes within the adipogenic cascade—CCAAT/Enhancer binding protein‐β, peroxisome proliferator‐activated receptor‐γ, and fatty acid‐binding protein—and consequentially increased lipid accumulation in a time‐ and viral dose‐dependent manner. Induction of hASC to the adipocyte state by Ad‐36 was further supported by increased expression of lipoprotein lipase and the accumulation of its extracellular fraction. hASC from subjects harboring Ad‐36 DNA in their adipose tissue due to natural infection had significantly greater ability to differentiate compared with Ad‐36 DNA‐negative counterparts, which offers a proof of concept. Thus, Ad‐36 has the potential to induce adipogenesis in hASC, which may contribute to adiposity induced by the virus.

Sympathetic Neural Adaptation to Hypocaloric Diet With or Without Exercise Training in Obese Metabolic Syndrome Subjects

OBJECTIVE Sympathetic nervous system (SNS) overactivity contributes to the pathogenesis and target organ complications of obesity. This study was conducted to examine the effects of lifestyle interventions (weight loss alone or together with exercise) on SNS function. RESEARCH DESIGN AND METHODS Untreated men and women (mean age 55 ± 1 year; BMI 32.3 ± 0.5 kg/m2) who fulfilled Adult Treatment Panel III metabolic syndrome criteria were randomly allocated to either dietary weight loss (WL, n = 20), dietary weight loss and moderate-intensity aerobic exercise (WL+EX, n = 20), or no treatment (control, n = 19). Whole-body norepinephrine kinetics, muscle sympathetic nerve activity by microneurography, baroreflex sensitivity, fitness (maximal oxygen consumption), metabolic, and anthropometric measurements were made at baseline and 12 weeks. RESULTS Body weight decreased by −7.1 ± 0.6 and −8.4 ± 1.0 kg in the WL and WL+EX groups, respectively (both P < 0.001). Fitness increased by 19 ± 4% (P < 0.001) in the WL+EX group only. Resting SNS activity decreased similarly in the WL and WL+EX groups: norepinephrine spillover by −96 ± 30 and −101 ± 34 ng/min (both P < 0.01) and muscle sympathetic nerve activity by −12 ± 6 and −19 ± 4 bursts/100 heart beats, respectively (both P < 0.01), but remained unchanged in control subjects. Blood pressure, baroreflex sensitivity, and metabolic parameters improved significantly and similarly in the two lifestyle intervention groups. CONCLUSIONS The addition of moderate-intensity aerobic exercise training to a weight loss program does not confer additional benefits on resting SNS activity. This suggests that weight loss is the prime mover in sympathetic neural adaptation to a hypocaloric diet.

Metformin and lifestyle modification in polycystic ovary syndrome: systematic review and meta-analysis

BACKGROUND Polycystic ovary syndrome (PCOS) is a common endocrine disorder with diverse reproductive and metabolic features. It is underpinned by insulin resistance that is exacerbated by obesity. Lifestyle modification is the first line treatment in PCOS, but it is associated with low adherence and sustainability. In small studies, metformin improves outcomes such as hyperinsulinaemia, ovulation and menstrual cyclicity. We conducted a systematic review and meta-analysis to compare the effect of lifestyle modification + metformin with lifestyle modification ± placebo, and of metformin alone with lifestyle modification ± placebo in PCOS on anthropometric, metabolic, reproductive and psychological outcomes. METHODS Databases including MEDLINE, EMBASE, Pubmed, Scopus, Cochrane, PsycINFO, CINAHL, Clinical Trials registry and ANZCTR were searched for RCTs conducted on humans and published in English up to August 2014. Inclusion criteria were diagnosis of PCOS based on Rotterdam criteria (inclusive of National Institutes of Health criteria) at any age and with any BMI. Interventions of interest included lifestyle + metformin (with any dose and any duration) or metformin alone compared with lifestyle ± placebo. RESULTS Of 2372 identified studies, 12 RCTs were included for analysis comprising 608 women with PCOS. Lifestyle + metformin were associated with lower BMI (mean difference (MD) -0.73 kg/m(2), 95% confidence intervals (CI) -1.14, -0.32, P = 0.0005) and subcutaneous adipose tissue (MD -92.49 cm(2), 95% CI -164.14, -20.84, P = 0.01) and increased number of menstrual cycles (MD 1.06, 95% CI 0.30, 1.82, P = 0.006) after 6 months compared with lifestyle ± placebo. There were no differences in other anthropometric, metabolic (surrogate markers of insulin resistance, fasting and area under the curve glucose, lipids and blood pressure), reproductive (clinical and biochemical hyperandrogenism), and psychological (quality of life) outcomes after 6 months between lifestyle + metformin compared with lifestyle ± placebo. With metformin alone compared with lifestyle ± placebo, weight and BMI were similar after 6 months, but testosterone was lower with metformin. CONCLUSIONS Lifestyle + metformin is associated with lower BMI and subcutaneous adipose tissue and improved menstruation in women with PCOS compared with lifestyle ± placebo over 6 months. Metformin alone compared with lifestyle showed similar BMI at 6 months. These results suggest the combination of lifestyle with metformin has a role to play in weight management: a key concern for women with PCOS. Existing study limitations include small sample sizes, short durations and risk of bias. With international guidelines now acknowledging that lifestyle and pharmacotherapy are required for weight loss and maintenance in obesity, future studies of appropriate size and duration are vital to clarify the role of metformin in PCOS management.

Targeted reduction of advanced glycation improves renal function in obesity

Obesity is highly prevalent in Western populations and is considered a risk factor for the development of renal impairment. Interventions that reduce the tissue burden of advanced glycation end-products (AGEs) have shown promise in stemming the progression of chronic disease. Here we tested if treatments that lower tissue AGE burden in patients and mice would improve obesity-related renal dysfunction. Overweight and obese individuals (body mass index (BMI) 26-39 kg/m(2)) were recruited to a randomized, crossover clinical trial involving 2 weeks each on a low- and a high-AGE-containing diet. Renal function and an inflammatory profile (monocyte chemoattractant protein-1 (MCP-1) and macrophage migration inhibitory factor (MIF)) were improved following the low-AGE diet. Mechanisms of advanced glycation-related renal damage were investigated in a mouse model of obesity using the AGE-lowering pharmaceutical, alagebrium, and mice in which the receptor for AGE (RAGE) was deleted. Obesity, resulting from a diet high in both fat and AGE, caused renal impairment; however, treatment of the RAGE knockout mice with alagebrium improved urinary albumin excretion, creatinine clearance, the inflammatory profile, and renal oxidative stress. Alagebrium treatment, however, resulted in decreased weight gain and improved glycemic control compared with wild-type mice on a high-fat Western diet. Thus, targeted reduction of the advanced glycation pathway improved renal function in obesity.

Higher prevalence of type 2 diabetes, metabolic syndrome and cardiovascular diseases in gypsies than in non-gypsies in Slovakia

OBJECTIVE Gypsies (or Roma) recently experienced a transition from a traditional to a Westernized lifestyle. Although mortality in this population is 4-fold higher compared with non-Gypsies, very limited information is available on their morbidity especially with regard to non-communicable diseases. Our aim was to determine the prevalence of type 2 diabetes mellitus (T2DM), metabolic syndrome and cardiovascular diseases in Gypsies and non-Gypsies living in the same region of southern Slovakia. MATERIALS AND METHODS We examined 156 Gypsies and 501 non-Gypsies who participated in a population survey. Age- and sex-standardized prevalence rates were computed for each of the following: T2DM, obesity, hyperlipidemia, hypertension, hyperinsulinemia, elevated albumin/creatinine ratio (ACR), metabolic syndrome and cardiovascular disease. RESULTS Age-sex standardized prevalence of T2DM was 30% (95% CI=22-39) in Gypsies and 10% (8-13, P=0.0001 for comparison of ethnic groups) in non-Gypsies. Corresponding prevalence of the other variables are: 65% (56-74) and 30% (26-34, P=0.0001) for obesity, 69% (61-76) and 59% (54-63, P=0.04) for hypercholesterolemia, 66% (59-74) and 39% (35-43, P=0.009) for hypertriglyceridemia, 49% (42-56) and 43% (39-47, P=0.1) for hypertension, 33% (26-50) and 8% (2-14, P=0.002) for hyperinsulinemia, 16% (9-22) and 5% (3-7, P=0.0001) for elevated ACR, 20% (12-27) and 4% (3-6, P=0.0001) for metabolic syndrome and 35% (28-43) and 26% (22-29, P=0.004) for cardiovascular disease. CONCLUSIONS Compared with non-Gypsies, Gypsies had a much higher prevalence of T2DM, metabolic syndrome and cardiovascular disease, which may contribute to their higher mortality.

Consumption of a diet low in advanced glycation end products for 4 weeks improves insulin sensitivity in overweight women

OBJECTIVE High-heat cooking of food induces the formation of advanced glycation end products (AGEs), which are thought to impair glucose metabolism in type 2 diabetic patients. High intake of fructose might additionally affect endogenous formation of AGEs. This parallel intervention study investigated whether the addition of fructose or cooking methods influencing the AGE content of food affect insulin sensitivity in overweight individuals. RESEARCH DESIGN AND METHODS Seventy-four overweight women were randomized to follow either a high- or low-AGE diet for 4 weeks, together with consumption of either fructose or glucose drinks. Glucose and insulin concentrations—after fasting and 2 h after an oral glucose tolerance test—were measured before and after the intervention. Homeostasis model assessment of insulin resistance (HOMA-IR) and insulin sensitivity index were calculated. Dietary and urinary AGE concentrations were measured (liquid chromatography tandem mass spectrometry) to estimate AGE intake and excretion. RESULTS When adjusted for changes in anthropometric measures during the intervention, the low-AGE diet decreased urinary AGEs, fasting insulin concentrations, and HOMA-IR, compared with the high-AGE diet. Addition of fructose did not affect any outcomes. CONCLUSIONS Diets with high AGE content may increase the development of insulin resistance. AGEs can be reduced by modulation of cooking methods but is unaffected by moderate fructose intake.

The complex immunological and inflammatory network of adipose tissue in obesity.

A number of approaches have been utilized in the prevention, management, and treatment of obesity, including, surgery, medication, diet, exercise, and overall lifestyle changes. Despite these interventions, the prevalence of obesity and the various disorders related to it is growing. In obesity, there is a constant state of chronic low-grade inflammation which is characterized by activation and infiltration of pro-inflammatory immune cells and a dysregulated production of high levels of pro-inflammatory cytokines. This pro-inflammatory milieu contributes to insulin resistance, type-2 diabetes, cardiovascular disease, and other related co-morbidities. The roles of the innate (macrophages, neutrophils, eosinophils, mast cells, NK cells, MAIT cells) and the adaptive (CD4 T cells, CD8 T cells, regulatory T cells, and B cells) immune responses and the roles of adipokines and cytokines in adipose tissue inflammation and obesity are discussed. An understanding of the crosstalk between the immune system and adipocytes may shed light in better treatment modalities for obesity and obesity-related diseases.

The Role of Traditional Cardiovascular Risk Factors Among Patients with Rheumatoid Arthritis

Objective People with rheumatoid arthritis (RA) have an increased risk of cardiovascular disease (CVD) compared with the general population. We investigated the relative contribution of traditional cardiovascular risk factors to this elevated risk. Methods Fifty RA subjects and 150 age and sex matched controls attended a cardiovascular risk assessment clinic betweenMarch and July 2006. Traditional cardiovascular risk factors and the absolute risks of CVD (calculated from application of a Framingham risk equation) were compared between the 2 groups. Results Compared with the controls, RA subjects were more likely to smoke (p < 0.001), be physically inactive (p = 0.006), and have higher mean measurements of body mass index (p = 0.040) and waist circumference (p = 0.049). No significant differences were found in mean levels of plasma lipid or glucose, or in the prevalences of diabetes and hypertension. Overall, the mean absolute risk of CVD was higher in the RA group, even after excluding smokers (p = 0.036). Conclusion Smoking and physical inactivity are important risk factors in the management of cardiovascular risk among patients with RA. Subjects with RA seem to have higher absolute risks of CVD compared with controls, even independently of smoking. This highlights the importance of treating all modifiable risk factors in those with RA although, individually, few may be conspicuous.

Inflammatory and Other Biomarkers: Role in Pathophysiology and Prediction of Gestational Diabetes Mellitus.

Understanding pathophysiology and identifying mothers at risk of major pregnancy complications is vital to effective prevention and optimal management. However, in current antenatal care, understanding of pathophysiology of complications is limited. In gestational diabetes mellitus (GDM), risk prediction is mostly based on maternal history and clinical risk factors and may not optimally identify high risk pregnancies. Hence, universal screening is widely recommended. Here, we will explore the literature on GDM and biomarkers including inflammatory markers, adipokines, endothelial function and lipids to advance understanding of pathophysiology and explore risk prediction, with a goal to guide prevention and treatment of GDM.