Lifestyle intervention in individuals with normal versus impaired glucose tolerance

NMR spectroscopy for metabolomics in the living system: recent progress and future challenges

Metabolism is a fundamental process that underlies human health and diseases. Nuclear magnetic resonance (NMR) techniques offer a powerful approach to identify metabolic processes and track the flux of metabolites at the molecular level in living systems. An in vitro study through in-cell NMR tracks metabolites in real time and investigates protein structures and dynamics in a state close to their most natural environment. This technique characterizes metabolites and proteins involved in metabolic pathways in prokaryotic and eukaryotic cells. In vivo magnetic resonance spectroscopy (MRS) enables whole-organism metabolic monitoring by visualizing the spatial distribution of metabolites and targeted proteins. One limitation of these NMR techniques is the sensitivity, for which a possible improved approach is through isotopic enrichment or hyperpolarization methods, including dynamic nuclear polarization (DNP) and parahydrogen-induced polarization (PHIP). DNP involves the transfer of high polarization from electronic spins of radicals to surrounding nuclear spins for signal enhancements, allowing the detection of low-abundance metabolites and real-time monitoring of metabolic activities. PHIP enables the transfer of nuclear spin polarization from parahydrogen to other nuclei for signal enhancements, particularly in proton NMR, and has been applied in studies of enzymatic reactions and cell signaling. This review provides an overview of in-cell NMR, in vivo MRS, and hyperpolarization techniques, highlighting their applications in metabolic studies and discussing challenges and future perspectives.

Road map for personalized exercise medicine in T2DM

The number of patients with type 2 diabetes mellitus (T2DM) is rising at an alarming rate. Regular physical activity and exercise are cornerstones in the therapy of T2DM. While a one-size-fits-all approach fails to account for many between-subject differences, the use of personalized exercise medicine has the potential of optimizing health outcomes. Here, a road map for personalized exercise therapy targeted at patients with T2DM is presented. It considers secondary complications, glucose management, response heterogeneity, and other relevant factors that might influence the effectiveness of exercise as medicine, taking exercise-medication-diet interactions, as well as feasibility and acceptance into account. Furthermore, the potential of artificial intelligence and machine learning-based applications in assisting sports therapists to find appropriate exercise programs is outlined.

Practical dietary advices for subjects with alpha-1 antitrypsin deficiency

Congenital alpha-1 antitrypsin deficiency (AATD) is a rare inherited disorder caused by the mutation of the SERPINA1 gene on chromosome 14. At pulmonary level, AAT deficiency leads to an increased risk of chronic obstructive pulmonary disease (COPD) and emphysema, starting from the third-fourth decade of life. At hepatic level, some variants of the allelic, in particular PI*Z, cause a conformational change of the AAT molecule, which polymerizes within the hepatocytes. Excessive hepatic accumulation of these abnormal molecules can lead to liver disease in both adults and children, with clinical presentation ranging from cholestatic jaundice in the newborn to abnormal blood indices of liver function in children and adults, up to fatty liver, cirrhosis and hepatocarcinoma. Nutritional interventions in AATD aim to provide the necessary calories, stop protein catabolism, prevent and treat malnutrition as in the case of common COPD, and even take into account any liver disease that is a distinctive trait, compared to common COPD. Actually, there is a lack of formal research regarding the effects of specific nutritional recommendations in patients with AATD, proper eating habits may help to preserve lung and liver function. For practical dietary advice in patients with AATD and COPD, recently a food pyramid proposal has been published. It has been observed that there is a marked overlap between AATD liver disease and obesity-related liver disease, suggesting shared molecular basis and, therefore, similar nutritional strategies. In this narrative review dietary advice for all possible stages of liver disease have been reported.

ESPEN practical guideline: Clinical nutrition in liver disease

BACKGROUND

The Practical guideline is based on the current scientific ESPEN guideline on Clinical Nutrition in Liver Disease.

METHODS

It has been shortened and transformed into flow charts for easier use in clinical practice. The guideline is dedicated to all professionals including physicians, dieticians, nutritionists and nurses working with patients with chronic liver disease.

RESULTS

A total of 103 statements and recommendations are presented with short commentaries for the nutritional and metabolic management of patients with (i) acute liver failure, (ii) alcoholic steatohepatitis, (iii) non-alcoholic fatty liver disease, (iv) liver cirrhosis, and (v) liver surgery/transplantation. The disease-related recommendations are preceded by general recommendations on the diagnostics of nutritional status in liver patients and on liver complications associated with medical nutrition.

CONCLUSION

This practical guideline gives guidance to health care providers involved in the management of liver disease to offer optimal nutritional care.

Development and Validation of Two Self-Reported Tools for Insulin Resistance and Hypertension Risk Assessment in A European Cohort: The Feel4Diabetes-Study

Early identification of type 2 diabetes mellitus (T2DM) and hypertension (HTN) risk may improve prevention and promote public health. Implementation of self-reported scores for risk assessment provides an alternative cost-effective tool. The study aimed to develop and validate two easy-to-apply screening tools identifying high-risk individuals for insulin resistance (IR) and HTN in a European cohort. Sociodemographic, lifestyle, anthropometric and clinical data obtained from 1581 and 1350 adults (baseline data from the Feel4Diabetes-study) were used for the European IR and the European HTN risk assessment index respectively. Body mass index, waist circumference, sex, age, breakfast consumption, alcohol, legumes and sugary drinks intake, physical activity and sedentary behavior were significantly correlated with Homeostatic Model Assessment of IR (HOMA-IR) and/or HTN and incorporated in the two models. For the IR index, the Area Under the Curve (AUC), sensitivity and specificity for identifying individuals above the 75th and 95th of HOMA-IR percentiles were 0.768 (95%CI: 0.721-0.815), 0.720 and 0.691 and 0.828 (95%CI: 0.766-0.890), 0.696 and 0.778 respectively. For the HTN index, the AUC, sensitivity and specificity were 0.778 (95%CI: 0.680-0.876), 0.667 and 0.797. The developed risk assessment tools are easy-to-apply, valid, and low-cost, identifying European adults at high risk for developing T2DM or having HTN.

The molecular basis for current targets of NASH therapies

Introduction: Nonalcoholic steatohepatitis (NASH) is a leading cause of liver disease in children and adults, a major contributor to health-care expenditures, and now a leading reason for liver transplantation. Adopting lifestyle modifications with regular exercise and a focus on healthy eating habits is the primary recommendation. However, patients are often unable to achieve and sustain such changes for a variety of social, physical, psychological and genetic reasons. Thus, treatments that can prevent and reverse NASH and its associated fibrosis are a major focus of current drug development.Areas covered: This review covers the current understanding of lipotoxic liver injury in the pathogenesis of NASH and how lifestyle modification and the spectrum of drugs currently in clinical trials address the many pathways leading to the phenotype of NASH.Expert opinion: Contrary to the frequently expressed nihilistic view of our understanding of NASH and disappointment with clinical trial results, much is known about the pathogenesis of NASH and there is much reason to be optimistic that effective therapies will be identified in the next 5-10 years. Achieving this will require continued refinement of clinical trial endpoints, continued engagement of trial sponsors and regulatory authorities, and continued participation of dedicated patients in clinical trials.

Phenotypic Responses to a Lifestyle Intervention Do Not Account for Inter-Individual Variability in Glucose Tolerance for Individuals at High Risk of Type 2 Diabetes

Background: Lifestyle interventions have been shown to delay or prevent the onset of type 2 diabetes among high risk adults. A better understanding of the variability in physiological responses would support the matching of individuals with the best type of intervention in future prevention programmes, in order to optimize risk reduction. The purpose of this study was to determine if phenotypic characteristics at baseline or following a 12 weeks lifestyle intervention could explain the inter-individual variability in change in glucose tolerance in individuals with high risk for type 2 diabetes. Methods: In total, 285 subjects with normal glucose tolerance (NGT, FINDRISC score > 12), impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) were recruited for a 12 weeks lifestyle intervention. Glucose tolerance, insulin sensitivity, anthropometric characteristics and aerobic fitness were measured. Variability of responses was examined by grouping participants by baseline glycemic status, by cluster analysis based on the change in glucose tolerance and by Principal Component Analysis (PCA). Results: In agreement with other studies, the mean response to the 12 weeks intervention was positive for the majority of parameters. Overall, 89% improved BMI, 80% waist circumference, and 81% body fat while only 64% improved fasting plasma glucose and 60% 2 h glucose. The impact of the intervention by glycaemic group did not show any phenotypic differences in response between NGT, IFG, and IGT. A hierarchical cluster analysis of change in glucose tolerance identified four sub-groups of "responders" (high and moderate) and "non-responders" (no response or deteriorated) but there were few differences in baseline clincal and physiological parameters or in response to the intervention to explain the overall variance. A further PCA analysis of 19 clinical and physiological univariables could explain less than half (48%) of total variability. Conclusion: We found that phenotypic characteristics from standard clinical and physiological parameters were not sufficient to account for the inter-individual variability in glucose tolerance following a 12 weeks lifestyle intervention in inidivuals at high risk for type 2 diabetes. Further work is required to identify biomarkers that complement phenotypic traits and better predict the response to glucose tolerance.

ESPEN guideline on clinical nutrition in liver disease

This update of evidence-based guidelines (GL) aims to translate current evidence and expert opinion into recommendations for multidisciplinary teams responsible for the optimal nutritional and metabolic management of adult patients with liver disease. The GL was commissioned and financially supported by ESPEN. Members of the guideline group were selected by ESPEN. We searched for meta-analyses, systematic reviews and single clinical trials based on clinical questions according to the PICO format. The evidence was evaluated and used to develop clinical recommendations implementing the SIGN method. A total of 85 recommendations were made for the nutritional and metabolic management of patients with acute liver failure, severe alcoholic steatohepatitis, non-alcoholic fatty liver disease, liver cirrhosis, liver surgery and transplantation as well as nutrition associated liver injury distinct from fatty liver disease. The recommendations are preceded by statements covering current knowledge of the underlying pathophysiology and pathobiochemistry as well as pertinent methods for the assessment of nutritional status and body composition.

Aerobic training performed at ventilatory threshold improves liver enzymes and lipid profile related to non-alcoholic fatty liver disease in adolescents with obesity

BACKGROUND

Despite the positive effects of high-intensity training on weight management and health-related outcomes, it is postulated that high-intensity training may also induce oxidative stress, increasing hepatic damage.

AIM

The aim of this study was to compare the effects of low versus high-intensity training on biomarkers related to non-alcoholic fatty liver disease (NAFLD) in adolescents with obesity.

METHODS

For this study 107 adolescents (15 ± 1 years) with obesity (BMI = 34.7 ± 4.1 kg/m²) were randomized into High-Intensity Training (HIT, n = 31), Low-Intensity Training (LIT, n = 31) or Control Group (CG, n = 45). Adolescents from HIT and LIT received nutritional, psychological and clinical counseling. Blood lipids, Castelli risk index, glucose, insulin and hepatic enzymes were measured at baseline and after 12 weeks.

RESULTS

Castelli risk index 1 was reduced in all groups ( p < 0.001) with moderate effect size ( d) for HIT ( d = 0.62) and LIT ( d = 0.66). Castelli risk index 2 also decreased ( p < 0.001 for all groups; HIT d = 0.65; LIT d = 0.79). High-density lipoprotein increased in all groups ( d = 0.25 and d = 0.18 in HIT and LIT), while alanine aminotransferase tended to reduce ( p = 0.062) in HIT ( d = 0.34) and LIT ( d = 0.73) and aspartate aminotransferase decreased ( p = 0.024) in both HIT ( d = 0.24) and LIT ( d = 0.45). There were no changes in glucose, insulin and insulin resistance.

CONCLUSION

Both high and low-intensity training improved biomarkers related to NAFLD. Thus, high-intensity training can be a safe and effective alternative to prevent and treat NAFLD in adolescents with obesity.

The relationship of serum alanine aminotransferase normal-range levels to arterial stiffness and metabolic syndrome in non-drinkers and drinkers: a Chinese community-based analysis

Background

Few studies have investigated the relationship between carotid-femoral pulse wave velocity (cfPWV) and serum alanine aminotransferase (ALT) normal-range levels across the world. The current analysis was designed to explore the relationship of serum ALT normal-range levels to cfPWV and metabolic syndrome (Mets) in non-drinkers and drinkers in a Chinese community-dwelling population.

Methods

There were 2202 participants with serum ALT levels within normal range enrolled for the current analysis.

Results

Median (range) age of participants was 53 (18–96) years, 51.5% were males, and 31.2% were drinkers. Prevalence of Mets was 29.4%. Median (range) of cfPWV was 10.1 (2.4-32.7) m/s. Hazard ratios for prevalence of Mets, central obesity and high triglyceride significantly increased with elevated levels of serum ALT in both non-drinkers and drinkers (p < 0.05 for all). Hazard ratios for prevalence of cfPWV > 10 m/s, high blood pressure and high blood glucose significantly increased with elevated levels of serum ALT in non-drinkers (p < 0.05 for all), but not in drinkers (p ≥ 0.05 for all).

Conclusions

In a Chinese community-dwelling population, prevalence of Mets and its components (including central obesity and high TG) increased with an elevation in serum ALT levels within normal range in both non-drinkers and drinkers, while cfPWV and other components of Mets, such as high blood pressure and glucose, increased with an elevation in serum ALT levels in non-drinkers, but not in drinkers.

Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) comprises a disease spectrum ranging from benign hepatic steatosis to non-alcoholic steatohepatitis with inflammation (NASH) and liver cirrhosis. NAFLD is now recognised as the hepatic manifestation of the metabolic syndrome. Simple steatosis is benign, whereas NASH can progress to cirrhosis with its resultant complications. Liver biopsy remains the gold standard in the diagnosis of NAFLD/NASH. Lifestyle and dietary modifications to achieve sustained weight loss is the cornerstone of NAFLD/NASH treatment.

The impact of insulin resistance on the kidney and vasculature

Insulin resistance is a systemic disorder that affects many organs and insulin-regulated pathways. The disorder is characterized by a reduced action of insulin despite increased insulin concentrations (hyperinsulinaemia). The effects of insulin on the kidney and vasculature differ in part from the effects on classical insulin target organs. Insulin causes vasodilation by enhancing endothelial nitric oxide production through activation of the phosphatidylinositol 3-kinase pathway. In insulin-resistant states, this pathway is impaired and the mitogen-activated protein kinase pathway stimulates vasoconstriction. The action of insulin on perivascular fat tissue and the subsequent effects on the vascular wall are not fully understood, but the hepatokine fetuin-A, which is released by fatty liver, might promote the proinflammatory effects of perivascular fat. The strong association of salt-sensitive arterial hypertension with insulin resistance indicates an involvement of the kidney in the insulin resistance syndrome. The insulin receptor is expressed on renal tubular cells and podocytes and insulin signalling has important roles in podocyte viability and tubular function. Renal sodium transport is preserved in insulin resistance and contributes to the salt-sensitivity of blood pressure in hyperinsulinaemia. Therapeutically, renal and vascular insulin resistance can be improved by an integrated holistic approach aimed at restoring overall insulin sensitivity and improving insulin signalling.

Insulin sensitivity, body composition and adipose depots following 12 w combined endurance and strength training in dysglycemic and normoglycemic sedentary men

CONTEXT

Insulin resistance and dysglycemia are associated with physical inactivity and adiposity, and may be improved by exercise.

OBJECTIVE

Investigate the effect of exercise on insulin sensitivity, body composition and adipose depots in sedentary men with (n = 11) or without (n = 11) overweight and dysglycemia.

MATERIAL AND METHODS

Euglycemic-hyperinsulinemic clamp, ankle-to-neck MRI, MRS, muscle and adipose tissue biopsies before and after 12 weeks combined strength and endurance exercise.

RESULTS

Insulin sensitivity, VO₂max, strength, whole-body and muscle fat content, and abdominal adipose depots were improved without obvious differences between normo- and dysglycemic men. Hepatic fat, waist circumference and subcutaneous adipose tissue were reduced in the dysglycemic group. For both groups plasma adiponectin was reduced, whereas IL-6 was unchanged. Visceral fat was preferentially lost compared with other adipose depots.

DISCUSSION AND CONCLUSION

Body composition, fat distribution and insulin sensitivity improved following training in sedentary middle-aged men with and without dysglycemia.

Non-alcoholic fatty liver diseases: update on the challenge of diagnosis and treatment

The prevalence of non-alcoholic fatty liver disease (NAFLD) is estimated to be 25-30% of the population, and is the most common cause of elevated liver enzymes in Korea. NAFLD is a “hot potato” for pharmaceutical companies. Many clinical trials are underway to develop a first-in-class drug to treat NAFLD. However, there are several challenging issues regarding the diagnosis of NAFLD. Currently, liver biopsy is the gold standard method for the diagnosis of NAFLD and steatohepatitis. Ideally, globally recognized standards for histological diagnosis and methods to optimize observer agreement on biopsy interpretation should be developed. Liver biopsy is the best method rather than a perfect one. Recently, multi-parametric magnetic resonance imagery can estimate the amount of intrahepatic fat successfully and is widely used in clinical trials. But no diagnostic method can discriminate between steatohepatitis and simple steatosis. The other unresolved issue in regard to NAFLD is the absence of satisfactory treatment options. Vitamin E and obeticholic acid have shown protective effects in randomized controlled trials, but this drug has not been approved for use in Korea. This study will provide a description of diagnostic methods and treatments that are currently recommended for NAFLD.

Exercise and diabetes: relevance and causes for response variability

Exercise as a key prevention strategy for diabetes and obesity is commonly accepted and recommended throughout the world. Unfortunately, not all individuals profit to the same extent, some exhibit exercise resistance. This phenomenon of non-response to exercise is found for several endpoints, including glucose tolerance and insulin sensitivity. Since these non-responders are of notable quantity, there is the need to understand the underlying mechanisms and to identify predictors of response. This displays the basis to develop personalized training intervention regimes. In this review, we summarize the current knowledge on response variability, with focus on human studies and improvement of glucose homeostasis as outcome.

Polymorphism in the SIRT1 gene and parameters of metabolic syndrome in a sample of the adult Brazilian population

ABSTRACT Objective: To evaluate whether the single nucleotide polymorphism rs7895833 (A/G) of the gene SIRT1 is associated with metabolic syndrome criteria in a sample of Brazilian adults. Methods: Serum samples and oral mucosal cells were collected from 243 subjects aged 30 to 70 years. Biochemical, hormonal, and anthropometric data were obtained. The single nucleotide polymorphism rs7895833 (A/G) was analyzed by polymerase chain reaction using the amplification refractory mutation system. Results: Among the 243 study subjects, 100 (41.15%) were classified as non-metabolic syndrome and 143 (58.85%), as metabolic syndrome. The frequency of the single nucleotide polymorphism rs7895833 (A/G) did not differ between the groups. However, 111 patients (45.67%) were overweight (body mass index: 25-29.9 kg/m2). Blood glucose, total cholesterol, triglycerides, very low density lipoprotein, low density lipoprotein, waist and hip circumferences, and blood pressure were higher in the metabolic syndrome group than in the non-metabolic syndrome group. Free thyroxine 4, grown hormone, and insulin levels were within the normal range. The metabolic conditions of the patients with metabolic syndrome indicate biochemical, anthropometric, and hormonal changes characteristic of overweight and obesity. Conclusion: The SIRT1 polymorphism rs7895833 (A/G) is not associated with the metabolic syndrome in the adult Brazilian population.

Effect of aerobic exercise training dose on liver fat and visceral adiposity

BACKGROUND & AIMS

Aerobic exercise reduces liver fat and visceral adipose tissue (VAT). However, there is limited data from randomized trials to inform exercise programming recommendations. This study examined the efficacy of commonly prescribed exercise doses for reducing liver fat and VAT using a randomized placebo-controlled design.

METHODS

Inactive and overweight/obese adults received 8 weeks of either; i) low to moderate intensity, high volume aerobic exercise (LO:HI, 50% VO 2peak, 60 min, 4d/week); ii) high intensity, low volume aerobic exercise (HI:LO, 70% VO 2peak, 45 min, 3d/week); iii) low to moderate intensity, low volume aerobic exercise (LO:LO, 50% VO 2peak, 45 min, 3d/week); or iv) placebo (PLA). Liver fat (spectroscopy) and VAT (magnetic resonance imaging) were measured before and after intervention.

RESULTS

Forty-seven of the 48 (n = 12 in each group) participants completed the trial. There were no serious adverse events. There was a significant change in group × time interaction in liver fat, which reduced in HI:LO by 2.38 ± 0.73%, in LO:HI by 2.62 ± 1.00%, and in LO:LO by 0.84 ± 0.47% but not in PLA (increase of 1.10 ± 0.62%) (p = 0.04). There was a significant reduction in VAT in HI:LO (-258.38 ± 87.78 cm(3)), in LO:HI (-386.80 ± 119.5 cm(3)), and in LO:LO (-212.96 ± 105.54 cm(3)), but not in PLA (92.64 ± 83.46 cm(3)) (p = 0.03). There were no significant differences between the dose or intensity of the exercise regimen and reductions in liver fat or VAT (p > 0.05).

CONCLUSION

The study found no difference in efficacy of liver fat reduction by either aerobic exercise dose or intensity. All of the aerobic exercise regimens employed reduced liver fat and VAT by a small amount without clinically significant weight loss.

Role of diet on non-alcoholic fatty liver disease: An updated narrative review

The purpose of this article review is to update what is known about the role of diet on non-alcoholic fatty liver disease (NAFLD). NAFLD is the most common cause of chronic liver disease in the developed world and is considered to be a spectrum, ranging from fatty infiltration of the liver alone (steatosis), which may lead to fatty infiltration with inflammation known as non alcoholic steatohepatitis While the majority of individuals with risk factors like obesity and insulin resistance have steatosis, only few people may develop steatohepatitis. Current treatment relies on weight loss and exercise, although various insulin-sensitizing medications appear promising. Weight loss alone by dietary changes has been shown to lead to histological improvement in fatty liver making nutrition therapy to become a cornerstone of treatment for NAFLD. Supplementation of vitamin E, C and omega 3 fatty acids are under consideration with some conflicting data. Moreover, research has been showed that saturated fat, trans-fatty acid, carbohydrate, and simple sugars (fructose and sucrose) may play significant role in the intrahepatic fat accumulation. However, true associations with specific nutrients yet to be clarified.

Metabolic syndrome and lifestyle modification

A clustering of metabolic abnormalities such as dyslipidemia, hypertension, and diabetes mellitus, all of which are major risk factors for cardiovascular disease (CVD), occurs more often than by chance. Numerous epidemiological studies, as well as basic researches, have revealed that visceral fat accumulation is closely involved in this risk clustering. This morbid condition is now well recognized as the metabolic syndrome. The concept of the metabolic syndrome, i.e., the involvement of visceral adiposity in the clustering of CVD risk factors, implies that an effective CVD risk reduction will be accomplished by an intervention to reduce visceral fat deposits. The primary strategy of the intervention is lifestyle modification, which can be put into practice in healthcare fields, without necessity of medical treatment. Now that CVD is a leading global health burden, the metabolic syndrome attracts increasing attention in the world. To take global action against the syndrome, several working groups developed its internationally unified diagnostic criteria. Most recently, the International Diabetes Federation (IDF) and the American Heart Association/National Heart, Lung, and Blood Institute (AHA/NHLBI) jointly proposed the criteria, although some cautions will be needed in their practical use. In this review, we mainly focus on the findings observed in clinical and epidemiological studies, to discuss a practical strategy of the management of the metabolic syndrome in healthcare fields.

Management of nonalcoholic fatty liver disease: an evidence-based clinical practice review

AIM

To build a consensus among Chilean specialists on the appropriate management of patients with nonalcoholic fatty liver disease (NAFLD) in clinical practice.

METHODS

NAFLD has now reached epidemic proportions worldwide. The optimal treatment for NAFLD has not been established due to a lack of evidence-based recommendations. An expert panel of members of the Chilean Gastroenterological Society and the Chilean Hepatology Association conducted a structured analysis of the current literature on NAFLD therapy. The quality of the evidence and the level of recommendations supporting each statement were assessed according to the recommendations of the United States Preventive Services Task Force. A modified three-round Delphi technique was used to reach a consensus among the experts.

RESULTS

A group of thirteen experts was established. The survey included 17 open-ended questions that were distributed among the experts, who assessed the articles associated with each question. The levels of agreement achieved by the panel were 93.8% in the first round and 100% in the second and third rounds. The final recommendations support the indication of lifestyle changes, including diet and exercise, for all patients with NAFLD. Proven pharmacological therapies include only vitamin E and pioglitazone, which can be used in nondiabetic patients with biopsy-proven nonalcoholic steatohepatitis (the progressive form of NAFLD), although the long-term safety and efficacy of these therapies have not yet been established.

CONCLUSION

Current NAFLD management is rapidly evolving, and new pathophysiology-based therapies are expected to be introduced in the near future. All NAFLD patients should be evaluated using a three-focused approach that considers the risks of liver disease, diabetes and cardiovascular events.

Moderate diet-induced weight loss is associated with improved insulin sensitivity in middle-aged healthy obese Korean women

BACKGROUND/OBJECTIVE

The goal of the present study was to investigate the effects of moderate caloric restriction on β-cell function and insulin sensitivity in middle-aged obese Korean women.

SUBJECTS/METHODS

Fifty-seven obese pre-menopausal Korean women participated in a 12-week calorie restriction program. Data on total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), triglycerides (TG), and fasting serum levels of glucose, insulin, C-peptide, blood pressure, leptin and anthropometrics were collected. A dietary intake assessment was based on three days of food recording. Additionally, β-cell function [homeostasis model assessment of β-cell (HOMA-β), insulinogenic index (ISI), C-peptide:glucose ratio, and area under curve insulin/glucose (AUCins/glu)] and insulin sensitivity [homeostasis model assessment for insulin resistance (HOMA-IR), Quantitative insulin-sensitivity check index (QUICKI) and Matsuda index (MI)] were recorded.

RESULTS

When calories were reduced by an average of 422 kcal/day for 12 weeks, BMI (-2.7%), body fat mass (-10.2%), and waist circumference (-5%) all decreased significantly (P < 0.05). After calorie restriction, weight, body fat percentage, hip circumference, BP, TC, HDL-C, LDL-C, plasma glucose at fasting, insulin at fasting and 120 min, AUCglu and the insulin area under the curve all decreased significantly (all P < 0.05), while insulin sensitivity (HOMA-IR, QUICKI and Matsuda index) measured by OGTT improved significantly (P < 0.01).

CONCLUSIONS

Moderate weight loss due to caloric restriction with reduction in insulin resistance improves glucose tolerance and insulin sensitivity in middle-aged obese women and thereby may help prevent the development of type 2 diabetes mellitus.

Predictors of deterioration of glucose tolerance and effects of lifestyle intervention aimed at reducing visceral fat in normal glucose tolerance subjects with abdominal obesity

Aims/Introduction:  The aim of the present study was to determine the predictors of deterioration of glucose tolerance in individuals with normal glucose tolerance (NGT) and abdominal obesity, and whether a lifestyle intervention to reduce visceral fat is effective in these individuals.

Materials and Methods:  The study subjects were 251 individuals who had abdominal obesity with certain risk factors (hypertension, high fasting plasma glucose (FPG), elevated hemoglobin A_1c (HbA_1c), dyslipidemia and hyperuricemia) and underwent oral glucose tolerance test (OGTT) in 2004 and 2005.

Results:  Using the area under the receiver operating characteristic curve, we found that PG at 0 min, 60 min, and area under the curve (AUC) of glucose from 0 to 120 min (AUC [glucose_0–120]) in OGTT were significant predictors of deterioration of glucose tolerance, with optimal cut‐off values of 95 mg/dL, 158 mg/dL and 271 mg h/dL, respectively. Although the rate of deterioration of glucose tolerance didn’t decrease with reductions in visceral fat area (VFA) over the 1‐year period in subjects with NGT, the rate tended to decrease with reductions in VFA in high‐risk NGT subjects (PG at 0 min > 95 or at 60 min > 158, or AUC [glucose_0–120] > 271).

Conclusions:  These results suggest that reduction of visceral fat over 1 year might not be beneficial in all subjects with NGT, but is beneficial in high‐risk NGT. We propose that individuals with values of the aforementioned predictors higher than the cut‐off levels, even those with NGT, should receive a lifestyle intervention program aimed at reducing visceral fat to prevent deterioration of glucose tolerance. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00080.x, 2011)

Relationship between obesity, metabolic syndrome, and nonalcoholic fatty liver disease in the elderly agricultural and fishing population of Taiwan

Background

The purpose of this study was to explore the relationship between obesity, the metabolic syndrome, and nonalcoholic fatty liver disease (NAFLD) in the elderly agricultural and fishing population of Taipei, Taiwan.

Methods

The study participants comprised 6,511 (3,971 male and 2,540 female) healthy elderly subjects voluntarily attending a teaching hospital for a physical check-up in 2010. Blood samples and real-time ultrasound-proven fatty liver sonography results were collected.

Results

The prevalence of NAFLD in this elderly population was 27.2%, including mild NAFLD (16.0%), moderate NAFLD (10.3%), and severe NAFLD (0.9%). The prevalence of moderate or severe NAFLD for metabolic syndrome proved to be substantially greater (P<0.0001, χ² test) for one or two metabolic factors. Using multinomial logistic regression analysis, age, sex, metabolic syndrome, and higher body mass index had a statistically significant association with mild NAFLD. Age, sex, metabolic syndrome, higher body mass index, and higher alanine aminotransferase were significantly related to moderate NAFLD. In addition, higher body mass index, higher uric acid, and higher alanine aminotransferase levels were significantly related to severe NAFLD. The sensitivity and specificity of body mass index and waist circumference as markers of NAFLD were estimated to be 81% and 84%, respectively, and 77% and 69%, respectively.

Conclusion

The prevalence of mild or moderate NAFLD was related to obesity and metabolic syndrome. Higher body mass index was also related to severe NAFLD but not to metabolic syndrome. Targeting this population for control of obesity and improved metabolic function is important.

Polymorphism rs3123554 in CNR2 reveals gender-specific effects on body weight and affects loss of body weight and cerebral insulin action

OBJECTIVE

The cannabinoid-receptor system is involved in the regulation of food intake. Here, we test whether single nucleotide polymorphisms (SNPs) in CNR2, encoding the cannabinoid-receptor 2, are associated with weight in a cross-sectional cohort. Furthermore, we wanted to investigate if the identified hits influence weight loss during lifestyle intervention; and study a potential involvement of cerebral insulin action.

METHODS

2006 subjects at increased risk for type 2 diabetes mellitus were genotyped for 5 tagging SNPs in the CNR2 locus. All subjects underwent a 75-g OGTT. 345 subjects participated in a lifestyle intervention (TUebingen Lifestyle Intervention Programme). Cerebrocortical insulin sensitivity was measured by magnetoencephalography after intranasal insulin application in 43 subjects.

RESULTS

In the cross-sectional cohort, the minor allele of rs3123554 was associated with lower BMI (Padd = 0.01, Prec = 0.004), and this was attributable to its effect in women only. Interestingly, during lifestyle intervention, carriers of the same allele lost less body weight (Padd = 0.03, Prec = 0.008). Moreover, carriers of this minor allele showed lower cerebral insulin sensitivity (Prec = 0.0402).

CONCLUSIONS

The minor allele of rs3123554 is associated cross-sectionally with lower body weight, whereas during intervention the same allele led to less reduction of body weight. Reduced cerebral insulin sensitivity in carriers of this allele might contribute to these disadvantageous effects during lifestyle intervention.

Long-lasting improvements in liver fat and metabolism despite body weight regain after dietary weight loss

OBJECTIVE

Weight loss reduces abdominal and intrahepatic fat, thereby improving metabolic and cardiovascular risk. Yet, many patients regain weight after successful diet-induced weight loss. Long-term changes in abdominal and liver fat, along with liver test results and insulin resistance, are not known.

RESEARCH DESIGN AND METHODS

We analyzed 50 overweight to obese subjects (46 ± 9 years of age; BMI, 32.5 ± 3.3 kg/m2; women, 77%) who had participated in a 6-month hypocaloric diet and were randomized to either reduced carbohydrates or reduced fat content. Before, directly after diet, and at an average of 24 (range, 17-36) months follow-up, we assessed body fat distribution by magnetic resonance imaging and markers of liver function and insulin resistance.

RESULTS

Body weight decreased with diet but had increased again at follow-up. Subjects also partially regained abdominal subcutaneous and visceral adipose tissue. In contrast, intrahepatic fat decreased with diet and remained reduced at follow-up (7.8 ± 9.8% [baseline], 4.5 ± 5.9% [6 months], and 4.7 ± 5.9% [follow-up]). Similar patterns were observed for markers of liver function, whole-body insulin sensitivity, and hepatic insulin resistance. Changes in intrahepatic fat und intrahepatic function were independent of macronutrient composition during intervention and were most effective in subjects with nonalcoholic fatty liver disease at baseline.

CONCLUSIONS

A 6-month hypocaloric diet induced improvements in hepatic fat, liver test results, and insulin resistance despite regaining of weight up to 2 years after the active intervention. Body weight and adiposity measurements may underestimate beneficial long-term effects of dietary interventions.

Whole body fat: content and distribution

Obesity and its co-morbidities, including type II diabetes, insulin resistance and cardiovascular diseases, have become one of the biggest health issues of present times. The impact of obesity goes well beyond the individual and is so far-reaching that, if it continues unabated, it will cause havoc with the economies of most countries. In order to be able to fully understand the relationship between increased adiposity (obesity) and its co-morbidity, it has been necessary to develop proper methodology to accurately and reproducibly determine both body fat content and distribution, including ectopic fat depots. Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) have recently emerged as the gold-standard for accomplishing this task. Here, we will review the use of different MRI techniques currently being used to determine body fat content and distribution. We also discuss the pros and cons of MRS to determine ectopic fat depots in liver, muscle, pancreas and heart and compare these to emerging MRI techniques currently being put forward to create ectopic fat maps. Finally, we will discuss how MRI/MRS techniques are helping in changing the perception of what is healthy and what is normal and desirable body-fat content and distribution.

Nor-1, a novel incretin-responsive regulator of insulin genes and insulin secretion

B-cell failure at the onset of type 2 diabetes is caused by a decline in β-cell function in the postprandial state and loss of pancreatic β-cell mass. Recently, we showed an association between increased insulin secretion and a single nucleotide polymorphism (SNP), SNP rs12686676, in the NR4A3 gene locus encoding the nuclear receptor Nor-1. Nor-1 is expressed in β-cells, however, not much is known about its function with regard to insulin gene expression and insulin secretion. Nor-1 is induced in a glucose-/incretin-dependent manner via the PKA pathway and directly induces insulin gene expression. Additionally, it stimulates insulin secretion possibly via regulation of potentially important genes in insulin exocytosis. Moreover, we show that the minor allele of NR4A3 SNP rs12686676 fully rescues incretin resistance provoked by a well-described polymorphism in TCF7L2. Thus, Nor-1 represents a promising new target for pharmacological intervention to fight diabetes.

Factors influencing participation in a vascular disease prevention lifestyle program among participants in a cluster randomized trial

Background

Previous research suggests that lifestyle intervention for the prevention of diabetes and cardiovascular disease (CVD) are effective, however little is known about factors affecting participation in such programs. This study aims to explore factors influencing levels of participation in a lifestyle modification program conducted as part of a cluster randomized controlled trial of CVD prevention in primary care.

Methods

This concurrent mixed methods study used data from the intervention arm of a cluster RCT which recruited 30 practices through two rural and three urban primary care organizations. Practices were randomly allocated to intervention (n = 16) and control (n = 14) groups. In each practice up to 160 eligible patients aged between 40 and 64 years old, were invited to participate. Intervention practice staff were trained in lifestyle assessment and counseling and referred high risk patients to a lifestyle modification program (LMP) consisting of two individual and six group sessions over a nine month period. Data included a patient survey, clinical audit, practice survey on capacity for preventive care, referral and attendance records at the LMP and qualitative interviews with Intervention Officers facilitating the LMP. Multi-level logistic regression modelling was used to examine independent predictors of attendance at the LMP, supplemented with qualitative data from interviews with Intervention Officers facilitating the program.

Results

A total of 197 individuals were referred to the LMP (63% of those eligible). Over a third of patients (36.5%) referred to the LMP did not attend any sessions, with 59.4% attending at least half of the planned sessions. The only independent predictors of attendance at the program were employment status - not working (OR: 2.39 95% CI 1.15-4.94) and having high psychological distress (OR: 2.17 95% CI: 1.10-4.30). Qualitative data revealed that physical access to the program was a barrier, while GP/practice endorsement of the program and flexibility in program delivery facilitated attendance.

Conclusion

Barriers to attendance at a LMP for CVD prevention related mainly to external factors including work commitments and poor physical access to the programs rather than an individuals’ health risk profile or readiness to change. Improving physical access and offering flexibility in program delivery may enhance future attendance. Finally, associations between psychological distress and attendance rates warrant further investigation.

Trial registration

ACTRN12607000423415

Dietary trans-fatty acid induced NASH is normalized following loss of trans-fatty acids from hepatic lipid pools

Previous experiments in mice showed that dietary trans-fats could play a role in non-alcoholic steatohepatitis (NASH) yet little is known about the accumulation trans-fats in hepatic lipid pools in relationship to liver injury. NASH is also associated with obesity yet improves with only modest weight loss. To distinguish the role of obesity versus sustained consumption of a trans-fat containing diet in causing NASH, mice with obesity and NASH induced by consuming a high trans-fat diet for 16 weeks were subsequently fed standard chow or maintained on trans-fat chow for another 8 weeks. The accumulation, partitioning and loss of trans-fats in the major hepatic lipid pools during and after trans-fat consumption were determined. Obese mice switched to standard chow remained obese but steatohepatitis improved. trans-fats were differentially incorporated into the major hepatic lipid pools and the loss of trans-fats after crossover to control chow was greatest in the cholesteryl ester pool. In summary, dietary changes can improve the biochemical and histopathological changes of NASH despite persistent obesity in mice. Analysis of hepatic lipids confirmed that dietary trans-fats accumulate in the major lipid pools and are released differentially with diet normalization. The substantial loss of trans-fats from the cholesteryl ester pool in parallel with improvement in NASH suggests that this pool of trans-fats could play a role in the pathogenesis of NASH.

Factors influencing participant enrolment in a diabetes prevention program in general practice: lessons from the Sydney diabetes prevention program

BACKGROUND

The effectiveness of lifestyle interventions in reducing diabetes incidence has been well established. Little is known, however, about factors influencing the reach of diabetes prevention programs. This study examines the predictors of enrolment in the Sydney Diabetes Prevention Program (SDPP), a community-based diabetes prevention program conducted in general practice, New South Wales, Australia from 2008-2011.

METHODS

SDPP was an effectiveness trial. Participating general practitioners (GPs) from three Divisions of General Practice invited individuals aged 50-65 years without known diabetes to complete the Australian Type 2 Diabetes Risk Assessment tool. Individuals at high risk of diabetes were invited to participate in a lifestyle modification program. A multivariate model using generalized estimating equations to control for clustering of enrolment outcomes by GPs was used to examine independent predictors of enrolment in the program. Predictors included age, gender, indigenous status, region of birth, socio-economic status, family history of diabetes, history of high glucose, use of anti-hypertensive medication, smoking status, fruit and vegetable intake, physical activity level and waist measurement.

RESULTS

Of the 1821 eligible people identified as high risk, one third chose not to enrol in the lifestyle program. In multivariant analysis, physically inactive individuals (OR: 1.48, P = 0.004) and those with a family history of diabetes (OR: 1.67, P = 0.000) and history of high blood glucose levels (OR: 1.48, P = 0.001) were significantly more likely to enrol in the program. However, high risk individuals who smoked (OR: 0.52, P = 0.000), were born in a country with high diabetes risk (OR: 0.52, P = 0.000), were taking blood pressure lowering medications (OR: 0.80, P = 0.040) and consumed little fruit and vegetables (OR: 0.76, P = 0.047) were significantly less likely to take up the program.

CONCLUSIONS

Targeted strategies are likely to be needed to engage groups such as smokers and high risk ethnic groups. Further research is required to better understand factors influencing enrolment in diabetes prevention programs in the primary health care setting, both at the GP and individual level.

Randomized trial of exercise effect on intrahepatic triglyceride content and lipid kinetics in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) and alterations in hepatic lipoprotein kinetics are common metabolic complications associated with obesity. Lifestyle modification involving diet-induced weight loss and regular exercise decreases intrahepatic triglyceride (IHTG) content and very low density lipoprotein (VLDL) triglyceride (TG) secretion rate. The aim of this study was to evaluate the weight loss-independent effect of following the physical activity guidelines recommended by the Department of Health and Human Services on IHTG content and VLDL kinetics in obese persons with NAFLD. Eighteen obese people (body mass index [BMI]: 38.1 ± 4.6 kg/m(2)) with NAFLD were randomized to 16 weeks of exercise training (45%-55% VO(2peak) , 30-60 minutes × 5 days/week; n = 12) or observation (control; n = 6). Magnetic resonance spectroscopy and stable isotope tracer infusions in conjunction with compartmental modeling were used to evaluate IHTG content and hepatic VLDL-TG and apolipoprotein B-100 (apoB-100) secretion rates. Exercise training resulted in a 10.3% ± 4.6% decrease in IHTG content (P < 0.05), but did not change total body weight (103.1 ± 4.2 kg before and 102.9 ± 4.2 kg after training) or percent body fat (38.9% ± 2.1% before and 39.2% ± 2.1% after training). Exercise training did not change the hepatic VLDL-TG secretion rate (17.7 ± 3.9 μmol/min before and 16.8 ± 5.4 μmol/min after training) or VLDL-apoB-100 secretion rate (1.5 ± 0.5 nmol/min before and 1.6 ± 0.6 nmol/min after training).

CONCLUSION

Following the Department of Health and Human Services recommended physical activity guidelines has small but beneficial effects on IHTG content, but does not improve hepatic lipoprotein kinetics in obese persons with NAFLD.

The secretion pattern of perivascular fat cells is different from that of subcutaneous and visceral fat cells

AIMS/HYPOTHESIS

We have previously found that the mass of perivascular adipose tissue (PVAT) correlates negatively with insulin sensitivity and post-ischaemic increase in blood flow. To understand how PVAT communicates with vascular vessels, interactions between perivascular, subcutaneous and visceral fat cells with endothelial cells (ECs) were examined with regard to inflammatory, metabolic and angiogenic proteins. To test for possible in vivo relevance of these findings, circulating levels of the predominant secretion product, hepatocyte growth factor (HGF), was measured in individuals carefully phenotyped for fat distribution patterns.

METHODS

Mono- and co-cultures of human primary fat cells with ECs were performed. mRNA expression and protein production were studied using Luminex, cytokine array, RealTime Ready and ELISA systems. Effects of HGF on vascular cells were determined by WST assays. In patients, HGF levels were measured by ELISA, and the mass of different fat compartments was determined by whole-body MRI.

RESULTS

In contrast with other fat cell types, PVAT cells released higher amounts of angiogenic factors, e.g. HGF, acidic fibroblast growth factor, thrombospondin-1, serpin-E1, monocyte chemotactic protein-1 and insulin-like growth factor-binding protein -3. Cocultures showed different expression profiles from monocultures, and mature adipocytes differed from pre-adipocytes. HGF was preferentially released by PVAT cells and stimulated EC growth and smooth muscle cell cytokine release. Finally, in 95 patients, only PVAT, not visceral or subcutaneous mass, correlated independently with serum HGF levels (p = 0.03; r = 0.225).

CONCLUSIONS

Perivascular (pre-)adipocytes differ substantially from other fat cells with regard to mRNA expression and protein production of angiogenic factors. This may contribute to fat tissue growth and atherosclerotic plaque complications. Higher levels of angiogenic factors, such as HGF, in patients with increased perivascular fat mass may have pathological relevance.

Role of obesity and lipotoxicity in the development of nonalcoholic steatohepatitis: pathophysiology and clinical implications

As obesity reaches epidemic proportions, nonalcoholic fatty liver disease (NAFLD) is becoming a frequent cause of patient referral to gastroenterologists. There is a close link between dysfunctional adipose tissue in NAFLD and common conditions such as metabolic syndrome, type 2 diabetes mellitus, and cardiovascular disease. This review focuses on the pathophysiology of interactions between adipose tissue and target organs in obesity and the resulting clinical implications for the management of nonalcoholic steatohepatitis. The release of fatty acids from dysfunctional and insulin-resistant adipocytes results in lipotoxicity, caused by the accumulation of triglyceride-derived toxic metabolites in ectopic tissues (liver, muscle, pancreatic beta cells) and subsequent activation of inflammatory pathways, cellular dysfunction, and lipoapoptosis. The cross talk between dysfunctional adipocytes and the liver involves multiple cell populations, including macrophages and other immune cells, that in concert promote the development of lipotoxic liver disease, a term that more accurately describes the pathophysiology of nonalcoholic steatohepatitis. At the clinical level, adipose tissue insulin resistance contributes to type 2 diabetes mellitus and cardiovascular disease. Treatments that rescue the liver from lipotoxicity by restoring adipose tissue insulin sensitivity (eg, significant weight loss, exercise, thiazolidinediones) or preventing activation of inflammatory pathways and oxidative stress (ie, vitamin E, thiazolidinediones) hold promise in the treatment of NAFLD, although their long-term safety and efficacy remain to be established. Better understanding of pathways that link dysregulated adipose tissue, metabolic dysfunction, and liver lipotoxicity will result in improvements in the clinical management of these challenging patients.

Improvement in insulin sensitivity following a 1-year lifestyle intervention program in viscerally obese men: contribution of abdominal adiposity

The objectives of the study were to quantify the effect of a 1-year healthy eating-physical activity/exercise lifestyle modification program on insulin sensitivity in viscerally obese men classified according to their glucose tolerance status and to evaluate the respective contributions of changes in body fat distribution vs changes in cardiorespiratory fitness (CRF) to the improvements in indices of plasma glucose/insulin homeostasis. Abdominally obese, dyslipidemic men (waist circumference ≥90 cm, triglycerides ≥1.69 mmol/L, and/or high-density lipoprotein cholesterol <1.03 mmol/L) were recruited. The 1-year intervention/evaluation was completed by 104 men. Body weight, composition, and fat distribution were assessed by dual-energy x-ray absorptiometry/computed tomography. Cardiorespiratory fitness and cardiometabolic risk profile were measured. After 1 year, insulin sensitivity improved in association with decreases in both visceral (VAT) and subcutaneous adiposity (SAT) as well as with the improvement in CRF, regardless of baseline glucose tolerance. Further analyses were performed according to changes in glucose tolerance status: improvement (group I, n = 39), no change (group N, n = 50), or worsening (group W, n = 15) after 1 year. Groups I and N improved their insulin sensitivity and their CRF, whereas group W did not, while losing less VAT than groups I and N. Multiple regressions showed that reduction in VAT was associated with an improvement in homeostasis model assessment of insulin resistance, whereas reduction in SAT was rather associated with improvement of the insulin sensitivity index of Matsuda. Changes in CRF were not independently associated with changes in indices of plasma glucose/insulin homeostasis. A 1-year lifestyle intervention improved plasma glucose/insulin homeostasis in viscerally obese men, including those with normal glucose tolerance status at baseline. Changes in SAT and VAT but not in CRF appeared to mediate these improvements.

High cerebral insulin sensitivity is associated with loss of body fat during lifestyle intervention

AIMS/HYPOTHESIS

Loss of weight and body fat are major targets in lifestyle interventions to prevent diabetes. In the brain, insulin modulates eating behaviour and weight control, resulting in a negative energy balance. This study aimed to test whether cerebral insulin sensitivity facilitates reduction of body weight and body fat by lifestyle intervention in humans.

METHODS

The study was performed as an additional arm of the TUebingen Lifestyle Intervention Program (TULIP). In 28 non-diabetic individuals (14 female/14 male; mean ± SE age 42 ± 2 years; mean ± SE BMI 29.9 ± 0.8 kg/m²), we measured cerebrocortical insulin sensitivity by using magnetoencephalography before lifestyle intervention. Total and visceral fat were measured by using MRI at baseline and after 9 months and 2 years of lifestyle intervention.

RESULTS

Insulin-stimulated cerebrocortical theta activity at baseline correlated with a reduction in total adipose tissue (r = -0.59, p = 0.014) and visceral adipose tissue (r = -0.76, p = 0.001) after 9 months of lifestyle intervention, accompanied by a statistical trend for reduction in body weight change (r = -0.37, p = 0.069). Similar results were obtained after 2 years.

CONCLUSIONS/INTERPRETATION

Our results suggest that high insulin sensitivity of the human brain facilitates loss of body weight and body fat during lifestyle intervention.

Notch-ligand expression by NALT dendritic cells regulates mucosal Th1- and Th2-type responses

Our previous studies showed that an adenovirus (Ad) serotype 5 vector expressing Flt3 ligand (Ad-FL) as nasal adjuvant activates CD11c(+) dendritic cells (DCs) for the enhancement of antigen (Ag)-specific IgA antibody (Ab) responses. In this study, we examined the molecular mechanism for activation of CD11c(+) DCs and their roles in induction of Ag-specific Th1- and Th2-cell responses. Ad-FL activated CD11c(+) DCs expressed increased levels of the Notch ligand (L)-expression and specific mRNA. When CD11c(+) DCs from various mucosal and systemic lymphoid tissues of mice given nasal OVA plus Ad-FL were cultured with CD4(+) T cells isolated from non-immunized OVA TCR-transgenic (OT II) mice, significantly increased levels of T cell proliferative responses were noted. Furthermore, Ad-FL activated DCs induced IFN-γ, IL-2 and IL-4 producing CD4(+) T cells. Of importance, these APC functions by Ad-FL activated DCs were down-regulated by blocking Notch-Notch-L pathway. These results show that Ad-FL induces CD11c(+) DCs to the express Notch-ligands and these activated DCs regulate the induction of Ag-specific Th1- and Th2-type cytokine responses.

An Endocrine Perspective of Nonalcoholic Fatty Liver Disease (NAFLD)

Endocrinologists are encountering patients with obesity-related complications such as metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM) on a daily basis. Nonalcoholic fatty liver disease (NAFLD) is a liver condition characterized by insulin resistance, hepatic steatosis and frequently T2DM. This is now the most common chronic liver condition in adults and is present in the majority of obese subjects. Liver fat accumulation may range from simple steatosis to severe steatohepatitis with hepatocyte necroinflammation (or nonalcoholic steatohepatitis [NASH]). Although the natural history is incompletely understood, NAFLD may lead to serious medical consequences ranging from cirrhosis and hepatocellular carcinoma to earlier onset of T2DM and cardiovascular disease (CVD). The diagnosis of NAFLD may be challenging because signs and symptoms are frequently absent or nonspecific, and thus easily missed. Liver aminotransferases may be helpful if elevated, but most times are normal in the presence of the disease. Liver imaging may assist in the diagnosis (ultrasound or MRI and spectroscopy) but a definitive diagnosis of NASH still requires a liver biopsy. This may change in the near future as novel biomarkers become available. Treatment of NAFLD includes aggressive management of associated cardiovascular risk factors and many times control of T2DM. Pioglitazone and vitamin E appear promising for patients with NASH, although long-term studies are unavailable. In summary, this review hopes to address the common clinical dilemmas that endocrinologists face in the diagnosis and management of NAFLD and increase awareness of a potentially serious medical condition.

Glycemia determines the effect of type 2 diabetes risk genes on insulin secretion

OBJECTIVE

Several single nucleotide polymorphisms (SNPs) in diabetes risk genes reduce glucose- and/or incretin-induced insulin secretion. Here, we investigated interactions between glycemia and such diabetes risk polymorphisms.

RESEARCH DESIGN AND METHODS

Insulin secretion was assessed by insulinogenic index and areas under the curve of C-peptide/glucose in 1,576 subjects using an oral glucose tolerance test (OGTT). Participants were genotyped for 10 diabetes risk SNPs associated with β-cell dysfunction: rs5215 (KCNJ11), rs13266634 (SLC30A8), rs7754840 (CDKAL1), rs10811661 (CDKN2A/2B), rs10830963 (MTNR1B), rs7903146 (TCF7L2), rs10010131 (WFS1), rs7923837 (HHEX), rs151290 (KCNQ1), and rs4402960 (IGF2BP2). Furthermore, the impact of the interaction between genetic variation in TCF7L2 and glycemia on changes in insulin secretion was tested in 315 individuals taking part in a lifestyle intervention study.

RESULTS

For the SNPs in TCF7L2 and WFS1, we found a significant interaction between glucose control and insulin secretion (all P ≤ 0.0018 for glucose × genotype). When plotting insulin secretion against glucose at 120 min OGTT, the compromising SNP effects on insulin secretion are most apparent under high glucose. In the longitudinal study, rs7903146 in TCF7L2 showed a significant interaction with baseline glucose tolerance upon change in insulin secretion (P = 0.0027). Increased glucose levels at baseline predicted an increase in insulin secretion upon improvement of glycemia by lifestyle intervention only in carriers of the risk alleles.

CONCLUSIONS

For the diabetes risk genes TCF7L2 and WFS1, which are associated with impaired incretin signaling, the level of glycemia determines SNP effects on insulin secretion. This indicates the increasing relevance of these SNPs during the progression of prediabetes stages toward clinically overt type 2 diabetes.

Exercise and fat accumulation in the human liver

PURPOSE OF REVIEW

Fat accumulation in the liver is strongly associated with metabolic dysfunction. Regular exercise improves many cardiometabolic risks factors; however, its effect on intrahepatic triglyceride (IHTG) content remains elusive. This article summarizes available data regarding the effects of exercise on IHTG.

RECENT FINDINGS

Several but not all observational studies report negative associations of habitual physical activity and cardiorespiratory fitness with IHTG and the prevalence of fatty liver. Aerobic exercise training in combination with hypocaloric diet reduces IHTG by a considerable amount (20-60%), even when weight loss is mild (<5%); hence weight loss per se may not be a critical factor. Longitudinal studies involving exercise training without dietary restriction and no weight loss demonstrate that increased cardiorespiratory fitness and reduced intra-abdominal adiposity are not invariably associated with liver fat depletion, whereas relatively large exercise-induced reductions in IHTG content (20-40%) can occur even in the absence of changes in body weight, body composition, or visceral adipose tissue. Although the majority of studies have examined aerobic training, resistance exercise has also been shown to be inversely associated with the prevalence of fatty liver in humans and effectively reduces IHTG content in animals.

SUMMARY

Exercise does hold promise as an effective treatment for hepatic steatosis; this field of research is still in its infancy, and there is much more to be learned.

The D299G/T399I Toll-like receptor 4 variant associates with body and liver fat: results from the TULIP and METSIM Studies

BACKGROUND

Toll-like-receptor 4 (TLR) is discussed to provide a molecular link between obesity, inflammation and insulin resistance. Genetic studies with replications in non-diabetic individuals in regard to their fat distribution or insulin resistance according to their carrier status of a common toll-like receptor 4 (TLR4) variant (TLR4(D299G/T399I)) are still lacking.

METHODOLOGY/PRINCIPAL FINDINGS

We performed a cross-sectional analysis in individuals phenotyped for prediabetic traits as body fat composition (including magnetic resonance imaging), blood glucose levels and insulin resistance (oral glucose tolerance testing, euglycemic hyperinsulinemic clamp), according to TLR4 genotype determined by candidate SNP analyses (rs4986790). We analyzed N = 1482 non-diabetic individuals from the TÜF/TULIP cohort (South Germany, aged 39±13 y, BMI 28.5±7.9, mean±SD) and N = 5327 non-diabetic participants of the METSIM study (Finland, males aged 58±6 y, BMI 26.8±3.8) for replication purposes. German TLR4(D299G/T399I) carriers had a significantly increased body fat (XG in rs4986790: +6.98%, p = 0.03, dominant model, adjusted for age, gender) and decreased insulin sensitivity (XG: -15.3%, Matsuda model, p = 0.04; XG: -20.6%, p = 0.016, clamp; both dominant models adjusted for age, gender, body fat). In addition, both liver fat (AG: +49.7%; p = 0.002) and visceral adipose tissue (AG: +8.2%; p = 0.047, both adjusted for age, gender, body fat) were significantly increased in rs4986790 minor allele carriers, and the effect on liver fat remained significant also after additional adjustment for visceral fat (p = 0.014). The analysis in METSIM confirmed increased body fat content in association with the rare G allele in rs4986790 (AG: +1.26%, GG: +11.0%; p = 0.010, additive model, adjusted for age) and showed a non-significant trend towards decreased insulin sensitivity (AG: -0.99%, GG: -10.62%).

CONCLUSIONS/SIGNIFICANCE

TLR4(D299G/T399I) associates with increased total body fat, visceral fat, liver fat and decreased insulin sensitivity in non-diabetic Caucasians and may contribute to diabetes risk. This finding supports the role of TLR4 as a molecular link between obesity and insulin resistance.

Lipidomics analysis reveals efficient storage of hepatic triacylglycerides enriched in unsaturated fatty acids after one bout of exercise in mice

Background

Endurance exercise induces lipolysis, increases circulating concentrations of free fatty acids (FFA) and the uptake and oxidation of fatty acids in the working muscle. Less is known about the regulation of lipid metabolism in the liver during and post-exercise.

Methodology/Principal Findings

We performed an ultra fast liquid chromatography-mass spectrometry (UFLC-MS) based lipidomics analysis of liver tissue samples obtained from C57Bl/6J mice immediately after a 60 min treadmill run of moderate intensity, and after 3 h of recovery. The PLS-DA scores plot for 115 quantified lipid molecular species revealed a clear separation of the hepatic lipid profile of sedentary from recovering mice, but not from mice immediately after running. 21 lipid species were considered to be most responsible for the difference in the hepatic lipid profiles, including 17 triacylglycerides (TG), one lysophosphatidylcholine (LPC) and three phosphatidylcholines (PC). TG species were found to be more abundant in the recovery phase, while PC species were decreased. The degree of accumulation of individual TG species correlated well with the amount of theoretical energy stored whereas no increase was found for TG species containing only saturated or one monounsaturated fatty acid. Total liver TG content as assayed by an enzymatic method was increased to 163% in the recovery phase, while it was significantly decreased in skeletal muscle by the exercise bout and remained less in the recovery phase. Results from fasted and refed mice indicate that fasting-induced lipolysis was associated with a pronounced accumulation of hepatic TG, which is reversed by refeeding for 5 h. Thus food intake per se did not elevate hepatic TG.

Conclusion

These data indicate that high availability of FFA induced by endurance exercise or fasting resulted in a transient hepatic TG accumulation, while muscle TG content was decreased during exercise presumably due to increased muscle fatty acid oxidation.