Dysregulation of glucose, insulin, triglyceride, blood pressure, and oxidative stress after an oral glucose tolerance test in men with abdominal obesity

Intestinal Epithelial NAD+ Biosynthesis Regulates GLP-1 Production and Postprandial Glucose Metabolism in Mice

Obesity is associated with perturbations in incretin production and whole-body glucose metabolism, but the precise underlying mechanism remains unclear. Here, we tested the hypothesis that nicotinamide phosphoribosyltransferase (NAMPT), which mediates the biosynthesis of nicotinamide adenine dinucleotide (NAD+), a key regulator of cellular energy metabolism, plays a critical role in obesity-associated intestinal pathophysiology and systemic metabolic complications. To this end, we generated a novel mouse model, namely intestinal epithelial cell-specific Nampt knockout (INKO) mice. INKO mice displayed diminished glucagon-like peptide-1 (GLP-1) production, at least partly contributing to reduced early-phase insulin secretion and postprandial hyperglycemia. Mechanistically, loss of NAMPT attenuated the Wnt signaling pathway, resulting in insufficient GLP-1 production. We also found that diet-induced obese mice had compromised intestinal NAMPT-mediated NAD+ biosynthesis and Wnt signaling pathway, associated with impaired GLP-1 production and whole-body glucose metabolism, resembling the INKO mice. Finally, administration of a key NAD+ intermediate, nicotinamide mononucleotide (NMN), restored intestinal NAD+ levels and obesity-associated metabolic derangements, manifested by a decrease in ileal Proglucagon expression and GLP-1 production as well as postprandial hyperglycemia in INKO and diet-induced obese mice. Collectively, our study provides mechanistic and therapeutic insights into intestinal NAD+ biology related to obesity-associated dysregulation of GLP-1 production and postprandial hyperglycemia.

Biotransformation profiles from a cohort of chronic fatigue women in response to a hepatic detoxification challenge

Chronic fatigue, in its various manifestations, frequently co-occur with pain, sleep disturbances and depression and is a non-communicable condition which is rapidly becoming endemic worldwide. However, it is handicapped by a lack of objective definitions and diagnostic measures. This has prompted the World Health Organization to develop an international instrument whose intended purpose is to improve quality of life (QOL), with energy and fatigue as one domain of focus. To complement this objective, the interface between detoxification, the exposome, and xenobiotic-sensing by nuclear receptors that mediate induction of biotransformation-linked genes, is stimulating renewed attention to a rational development of strategies to identify the metabolic profiles in complex multifactorial conditions like fatigue. Here we present results from a seven-year study of a cohort of 576 female patients suffering from low to high levels of chronic fatigue, in which phase I and phase II biotransformation was assessed. The biotransformation profiles used were based on hepatic detoxification challenge tests through oral caffeine, acetaminophen and acetylsalicylic acid ingestion coupled with oxidative stress analyses. The interventions indicated normal phase I but increased phase II glucuronidation and glycination conjugation. Complementarity was indicated between a fatigue scale, medical symptoms and associated energy-related parameters by application of Chi-square Automatic Interaction Detector (CHAID) analysis. The presented study provides a cluster of data from which we propose that multidisciplinary inputs from the combination of a fatigue scale, medical symptoms and biotransformation profiles provide the rationale for the development of a comprehensive laboratory instrument for improved diagnostics and personalized interventions in patients with chronic fatigue with a view to improving their QOL.

Perspective: Cardiovascular Responses to Sugar-Sweetened Beverages in Humans: A Narrative Review with Potential Hemodynamic Mechanisms

Cardiovascular diseases are still the primary cause of mortality worldwide, with high blood pressure and type 2 diabetes as major promoters. Over the past 3 decades, almost in parallel with the rise in cardiovascular disease incidence, the consumption of sugar-sweetened beverages (SSBs) has increased. In this context, SSBs are potential contributors to weight gain and increase the risk for elevations in blood pressure, type 2 diabetes, coronary heart disease, and stroke. Nevertheless, the mechanisms underlying the cardiovascular and metabolic responses to SSBs, in particular on blood pressure, are poorly understood. We discuss and propose potential mechanisms underlying differential effects of sugars on postprandial blood pressure regulation; provide evidence for additional molecular contributors, i.e., fibroblast growth factor 21, towards sugar-induced cardiovascular responses; and discuss potential cardiovascular neutral sugars. Furthermore, we explore whether pre-existing glucose intolerance in humans exacerbates the cardiovascular responses to SSBs, thus potentially aggravating the cardiovascular risk in already-susceptible individuals.

Correlation of insulin resistance and motor function in spinal and bulbar muscular atrophy

This study aimed to evaluate various metabolic parameters in patients with spinal and bulbar muscular atrophy (SBMA), to investigate the association between those indices and disease severity, and to explore the underlying molecular pathogenesis. We compared the degree of obesity, metabolic parameters, and blood pressure in 55 genetically confirmed SBMA patients against those in 483 age- and sex-matched healthy control. In SBMA patients, we investigated the correlation between these factors and motor functional indices. SBMA patients had lower body mass index, blood glucose, and Hemoglobin A1c, but higher blood pressure, homeostasis model assessment of insulin resistance (HOMA-IR, a marker of insulin resistance), total cholesterol, and adiponectin levels than the control subjects. There were no differences in visceral fat areas, high-density lipoprotein-cholesterol (HDL-C), or triglyceride levels in two groups. Revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R) correlated positively with HDL-C, but negatively with HOMA-IR. Through stepwise multiple regression analysis, we identified HOMA-IR as a significant metabolic determinant of ALSFRS-R. In biochemical analysis, we found that decreased expressions of insulin receptors, insulin receptor substrate-1 and insulin receptor-β, in autopsied muscles and fibroblasts of SBMA patients. This study demonstrates that SBMA patients have insulin resistance, which is associated with the disease severity. The expressions of insulin receptors are attenuated in the skeletal muscle of SBMA, providing a possible pathomechanism of metabolic alterations. These findings suggested that insulin resistance is a metabolic index reflecting disease severity and pathogenesis as well as a potential therapeutic target for SBMA.

Facing Morbid Obesity: How to Approach It

Obesity is a major public health problem, with a prevalence of 10% to 20% in Western Europe. Morbid obesity, characterized by body mass index >40 kg/m(2), showed an increased prevalence in the last 30 years. Obesity is associated with reduced economic and social opportunities, reduced quality of life, and is a determinant of several "intermediate risk factors," leading to an increased mortality and a loss in life expectancy. The rising prevalence of morbid obesity increased the demand for bariatric surgery, also called "metabolic surgery": after these interventions, there is a decrease in metabolic comorbidities, cardiovascular (CV) risk, and total mortality. In this review, we update the evaluation of morbid obese patients from the physical examination to the metabolic, CV and respiratory assessments in order to correctly stratify the CV risk and provide the best treatment. To obtain these achievements, multidisciplinary work has to be carried out with a team involving several experts with different skills.

Phenotypic flexibility as a measure of health: the optimal nutritional stress response test

Nutrition research is struggling to demonstrate beneficial health effects, since nutritional effects are often subtle and long term. Health has been redefined as the ability of our body to cope with daily-life challenges. Physiology acts as a well-orchestrated machinery to adapt to the continuously changing environment. We term this adaptive capacity “phenotypic flexibility.” The phenotypic flexibility concept implies that health can be measured by the ability to adapt to conditions of temporary stress, such as physical exercise, infections or mental stress, in a healthy manner. This may offer a more sensitive way to assess changes in health status of healthy subjects. Here, we performed a systematic review of 61 studies applying different nutritional stress tests to quantify health and nutritional health effects, with the objective to define an optimal nutritional stress test that has the potential to be adopted as the golden standard in nutrition research. To acknowledge the multi-target role of nutrition, a relevant subset of 50 processes that govern optimal health, with high relevance to diet, was used to define phenotypic flexibility. Subsequently, we assessed the response of biomarkers related to this subset of processes to the different challenge tests. Based on the obtained insights, we propose a nutritional stress test composed of a high-fat, high-caloric drink, containing 60 g palm olein, 75 g glucose and 20 g dairy protein in a total volume of 400 ml. The use of such a standardized nutritional challenge test in intervention studies is expected to demonstrate subtle improvements of phenotypic flexibility, thereby enabling substantiation of nutritional health effects.

Targeted metabolomic analysis reveals the association between the postprandial change in palmitic acid, branched-chain amino acids and insulin resistance in young obese subjects

Obesity is the result of a positive energy balance and often leads to difficulties in maintaining normal postprandial metabolism. The changes in postprandial metabolites after an oral glucose tolerance test (OGTT) in young obese Chinese men are unclear. In this work, the aim is to investigate the complex metabolic alterations in obesity provoked by an OGTT using targeted metabolomics. We used gas chromatography-mass spectrometry and ultra high performance liquid chromatography-triple quadrupole mass spectrometry to analyze serum fatty acids, amino acids and biogenic amines profiles from 15 control and 15 obese subjects at 0, 30, 60, 90 and 120 min during an OGTT. Metabolite profiles from 30 obese subjects as independent samples were detected in order to validate the change of metabolites. There were the decreased levels of fatty acid, amino acids and biogenic amines after OGTT in obesity. At 120 min, percent change of 20 metabolites in obesity has statistical significance when comparing with the controls. The obese parameters was positively associated with changes in arginine and histidine (P<0.05) and the postprandial change in palmitic acid (PA), branched-chain amino acids (BCAAs) and phenylalanine between 1 and 120 min were positively associated with fasting insulin and HOMA-IR (all P<0.05) in the obese group. The postprandial metabolite of PA and BCAAs may play important role in the development and onset of insulin resistance in obesity. Our findings offer new insights in the complex physiological regulation of the metabolism during an OGTT in obesity.

Associations of breaks in sedentary time with abdominal obesity in Portuguese older adults

In older adults, sedentary time is positively associated with obesity. The manner in which it is accumulated, i.e., the number of breaks in sedentary time, might be also important. We examined the cross-sectional associations of breaks in sedentary time with abdominal obesity in 301 older adults (111 men and 190 women) aged 75.0 ± 6.8 years. Sedentary time (counts min(-1) < 100) and physical activity were objectively measured by accelerometry, worn during waking hours for at least three consecutive days. A break was defined as an interruption (≥ 100 counts min(-1) < 2020) in sedentary time while performing light intensity physical activities. Sedentary time was expressed as the number of daily breaks in sedentary time or hourly breaks in sedentary time. Abdominal obesity was defined by waist circumference (men >102 cm; women >88 cm). Using binary logistic regression analyses, the odds for abdominal obesity decreased 7 % for each additional hourly break in sedentary time in women (OR = 0.93, 95 % CI: 0.87-1.00), but not men, independently of total sedentary time and moderate-to-vigorous physical activity. The odds for abdominal obesity were 3.21 times higher (p = 0.039) for women in quartile 1 (<225 breaks day(-1)) of daily breaks in sedentary time compared to those in quartile 4 (>353 breaks day(-1)) of daily breaks in sedentary time.These findings indicate that older women who interrupt their sedentary time more frequently are less likely to present abdominal obesity. Public health recommendations regarding breaking-up sedentary time complementary to those for physical activity are likely to be relevant.

Abdominal obesity is associated with heart disease in dogs

BACKGROUND

The relationship between overall obesity and fat distribution in dogs and the development of heart disease is unclear. In the present study we evaluated the association between overall obesity and fat distribution and clinical heart disease by morphometric and computed tomography (CT)-based measurements. Body condition score (BCS), modified body mass index (MBMI, kg/m2), waist-to-hock-to-stifle distance ratio (WHSDR), waist-to-ilium wing distance ratio (WIWDR), and waist-to-truncal length ratio (WTLR) were compared between dogs with (n = 44) and without (n = 43) heart disease using receiver operating characteristic (ROC) analysis. Intra-abdominal fat (IAF) and subcutaneous fat (SQF) were measured in dogs with (n = 8) and without (n = 9) heart disease at the center of the fourth and fifth lumbar vertebrae by CT.

RESULTS

BCS was similar between heart disease and healthy groups (3.6 ± 0.2 vs. 3.3 ± 0.1, P = 0.126). The following morphometric measurements were greater in the heart disease group compared with healthy canines: MBMI (65.0 ± 4.5 vs. 52.5 ± 3.7 kg/m2, respectively, P = 0.035); WIWDR (4.1 ± 0.1 vs. 3.1 ± 0.1, P < 0.01); and WTLR (1.25 ± 0.04 vs. 1.05 ± 0.04, P < 0.01). However, there was no significant difference in WHSDR (3.6 ± 0.1 vs. 3.7 ± 0.2, P = 0.875). Interestingly, IAF was significantly increased in dogs with heart disease compared with healthy dogs (23.5 ± 1.5% vs. 19.4 ± 1.2%, P = 0.039) whereas SQF was similar between two groups (35.5 ± 2.7% vs. 38.6 ± 3.5%, P = 0.496). Of the five morphometric indices studied, WIWDR and WTLR provided acceptable discrimination for diagnosing heart disease in dogs, with areas under the ROC curve of 0.778 (95% confidence interval [CI]:0.683-0.874) and 0.727 (95% CI:0.619-0.835), respectively.

CONCLUSIONS

Our data indicate that abdominal obesity, rather than overall obesity, is associated with heart disease in dogs. Measurements of both WIWDR and WTLR are particular useful for detection of an abdominal obesity in dogs.

Antidiabetic potential of phycocyanin: effects on KKAy mice

CONTEXT

Phycocyanin (PC) has been proven to have many therapeutic properties, but its effects on diabetes have not been investigated.

OBJECTIVE

Antidiabetic activity of PC isolated from Spirulina platensis was evaluated in this study.

MATERIALS AND METHODS

Oral administration of PC (100 mg/kg, once per day for 3 weeks) on KKAy mice were investigated by monitoring the changes in body weight, food intake, fasting plasma glucose level, 24 h random blood glucose levels, oral glucose tolerance tests (OGTTs), glycosylated serum protein (GSP), fasting serum insulin (FINS), glycogen, triglyceride (TG), total cholesterol (TC), total antioxidative capability (T-AOC) and malondialdehyde (MDA). Histopathological changes in the pancreas were also examined with hematoxylin-eosin staining.

RESULTS

Administration of PC significantly decreased the body weight, fasting plasma glucose, 24 h random blood glucose levels, FINS and GSP levels, TG and TC content in serum and livers, MDA content in livers (p < 0.05 or p < 0.01). On the other hand, glucose tolerance to glucose administration, T-AOC, and the content of glycogen in liver and muscle were enhanced following PC treatment (p < 0.05 or p < 0.01). Histopathological results showed that PC administration suppressed the abnormal enlargement of islets observed in the pancreas of KKAy mice.

DISCUSSION AND CONCLUSION

The antidiabetic effect of PC on KKAy mice is most likely due to its ability to enhance insulin sensitivity, amelioration of insulin resistance of peripheral target tissues and regulation of glucolipide metabolism. Therefore, PC may have a potential clinical utility in combating type-2 diabetes.

Plasma metabolomics and proteomics profiling after a postprandial challenge reveal subtle diet effects on human metabolic status

We introduce the metabolomics and proteomics based Postprandial Challenge Test (PCT) to quantify the postprandial response of multiple metabolic processes in humans in a standardized manner. The PCT comprised consumption of a standardized 500 ml dairy shake containing respectively 59, 30 and 12 energy percent lipids, carbohydrates and protein. During a 6 h time course after PCT 145 plasma metabolites, 79 proteins and 7 clinical chemistry parameters were quantified. Multiple processes related to metabolism, oxidation and inflammation reacted to the PCT, as demonstrated by changes of 106 metabolites, 31 proteins and 5 clinical chemistry parameters. The PCT was applied in a dietary intervention study to evaluate if the PCT would reveal additional metabolic changes compared to non-perturbed conditions. The study consisted of a 5-week intervention with a supplement mix of anti-inflammatory compounds in a crossover design with 36 overweight subjects. Of the 231 quantified parameters, 31 had different responses over time between treated and control groups, revealing differences in amino acid metabolism, oxidative stress, inflammation and endocrine metabolism. The results showed that the acute, short term metabolic responses to the PCT were different in subjects on the supplement mix compared to the controls. The PCT provided additional metabolic changes related to the dietary intervention not observed in non-perturbed conditions. Thus, a metabolomics based quantification of a standardized perturbation of metabolic homeostasis is more informative on metabolic status and subtle health effects induced by (dietary) interventions than quantification of the homeostatic situation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-011-0320-5) contains supplementary material, which is available to authorized users.

Cross-sectional and longitudinal study of association between circulating thiobarbituric acid-reacting substance levels and clinicobiochemical parameters in 1,178 middle-aged Japanese men - the Amagasaki Visceral Fat Study

Background

Circulating thiobarbituric acid-reacting substance (TBARS) levels, a marker of systemic oxidative stress, are predictive of cardiovascular events. However, they has not been evaluated in Japanese, especially with regard to the factors that contribute to the changes in circulating TBARS levels. We investigated the cross-sectional and longitudinal relationships between circulating TBARS levels and various clinicobiochemical parameters in middle-aged men.

Methods

In this population-based study (The Amagasaki Visceral Fat Study), 1,178 Japanese male urban workers who had undergone health check-ups in 2006, 2007 and 2008 and were not on medications for metabolic disorders during the follow-up period, were enrolled. Serum TBARS levels were measured by the method of Yagi. The estimated visceral fat area (eVFA) by bioelectrical impedance was measured annually. After health check-ups, subjects received health education with lifestyle modification by medical personnel.

Results

The number of cardiovascular risk factors (hypertension, hyperglycemia, low HDL-C, hypertriglyceridemia, hyperuricemia, hyper-LDL-C and impaired renal function) augmented with the increases in log-eVFA (p < 0.0001) and log-TBARS (p < 0.0001). The combination of TBARS and eVFA had a multiplicative effect on risk factor accumulation (F value = 79.1, p = 0.0065). Stepwise multiple regression analysis identified log-eVFA, as well as age, log-body mass index (BMI), LDL-C, log-adiponectin, γ-glutamyl transpeptidase (γ-GTP) and uric acid as significant determinants of log-TBARS. Stepwise multiple regression analysis identified one-year changes in eVFA as well as BMI, γ-GTP and estimated glomerular filtration rate (eGFR) as significant determinants of one-year change in TBARS, and biennial changes in eVFA as well as BMI and γ-GTP, eGFR as significant determinants of biennial change in TBARS.

Conclusions

The present study showed a significant cross-sectional and longitudinal correlation between TBARS and eVFA, as well as BMI and γ- GTP, eGFR. Visceral fat reduction may independently associate with the improvement in systemic ROS in middle-aged Japanese men.

Trial Registration

The Amagasaki Visceral Fat Study UMIN000002391.

26th Hohenheim Consensus Conference, September 11, 2010 Scientific substantiation of health claims: evidence-based nutrition

OBJECTIVE

The objective was to define the term evidence based nutrition on the basis of expert discussions and scientific evidence.

METHODS AND PROCEDURES

The method used is the established Hohenheim Consensus Conference. The term "Hohenheim Consensus Conference" defines conferences dealing with nutrition-related topics. The major aim of the conference is to review the state of the art of a given topic with experts from different areas (basic science, clinicians, epidemiologists, etc.). Based on eight to 12 questions, the experts discuss short answers and try to come to a consensus. A scientifically based text is formulated that justifies the consensus answer. To discuss the requirements for the scientific substantiation of claims, the 26th Hohenheim Consensus Conference gathered the views of many academic experts in the field of nutritional research and asked these experts to address the various aspects of a claims substantiation process and the possibilities and limitations of the different approaches.

RESULTS

The experts spent a day presenting and discussing their views and arrived at several consensus statements that can serve as guidance for bodies performing claims assessments in the framework of regulatory systems.

CONCLUSION

The 26th Hohenheim Consensus Conference addresses some general aspects and describes the current scientific status from the point of view of six case studies to illustrate specific areas of scientific interest: carotenoids and vitamin A in relation to age-related macular degeneration, the quality of carbohydrates (as expressed by the glycemic index) in relation to health and well-being, probiotics in relation to intestinal and immune functions, micronutrient intake and maintenance of normal body functions, and food components with antioxidative properties and health benefits.