Associations of visceral and liver fat with the metabolic syndrome across the spectrum of obesity: the AGES-Reykjavik study

The Important Role of Phosphatidylserine, ADAM17, TNF-Alpha, and Soluble MER on Efferocytosis Activity in Central Obesity

Background

Obesity is expected to hinder efferocytosis due to ADAM17-mediated cleavage of the MER tyrosine kinase receptor, producing soluble MER (sMER) that disrupts MERTK binding to cell death markers. However, the intracellular efferocytosis pathway in central obesity remains elusive, particularly the role of low-grade chronic inflammation in its initiation and identification of binding signals that disrupt efferocytosis.

Objective

We investigate the efferocytosis signaling pathway in men with central obesity and its relationship with inflammation, cell death, and related processes.

Methods

A cross-sectional study was conducted, and clinical data and blood samples were collected from 56 men with central obesity (obese group) and 29 nonobese individuals (control group). Clinical evaluations and predefined biochemical screening tests were performed. The efferocytosis signaling pathway was investigated by measuring phosphatidylserine (PS), ADAM17, TNF-alpha (TNF-α), and sMER.

Results

Metabolic syndrome was detected in more than half of the participants in the obese group according to the predefined tests. Mean levels of PS, TNF-α, and sMER were higher in the obese group but not significantly different from those of the control group. Further analysis based on waist circumference (WC) ranges in the obese group revealed a significant increase in PS and sMER levels between the control group and the obese group with WC greater than 120 cm. ADAM17 levels were significantly higher in the obese group than in the control group. PS was positively correlated with WC and ADAM17. ADAM17 was positively correlated with TNF-α and sMER, indicating impaired efferocytosis.

Conclusions

Central obesity appeared to cause a disturbance in efferocytosis that began with cell damage and death, along with an enlargement of the WC and an ongoing inflammatory response. Efferocytosis was disrupted by proinflammatory cytokine regulators, which induced the production of sMER and interfered with the efferocytosis process.

Metabolic syndrome: imaging features and clinical outcomes

Metabolic syndrome, which affects around a quarter of adults worldwide, is a group of metabolic abnormalities characterized mainly by insulin resistance and central adiposity. It is strongly correlated with cardiovascular and all-cause mortality. Early identification of the changes induced by metabolic syndrome in target organs and timely intervention (eg, weight reduction) can decrease morbidity and mortality. Imaging can monitor the main components of metabolic syndrome and identify early the development and progression of its sequelae in various organs. In this review, we discuss the imaging features across different modalities that can be used to evaluate changes due to metabolic syndrome, including fatty deposition in different organs, arterial stiffening, liver fibrosis, and cardiac dysfunction. Radiologists can play a vital role in recognizing and following these target organ injuries, which in turn can motivate lifestyle modification and therapeutic intervention.

Mechanisms of weight loss-induced remission in people with prediabetes: a post-hoc analysis of the randomised, controlled, multicentre Prediabetes Lifestyle Intervention Study (PLIS)

BACKGROUND

Remission of type 2 diabetes can occur as a result of weight loss and is characterised by liver fat and pancreas fat reduction and recovered insulin secretion. In this analysis, we aimed to investigate the mechanisms of weight loss- induced remission in people with prediabetes.

METHODS

In this prespecified post-hoc analysis, weight loss-induced resolution of prediabetes in the randomised, controlled, multicentre Prediabetes Lifestyle Intervention Study (PLIS) was assessed, and the results were validated against participants from the Diabetes Prevention Program (DPP) study. For PLIS, between March 1, 2012, and Aug 31, 2016, participants were recruited from eight clinical study centres (including seven university hospitals) in Germany and randomly assigned to receive either a control intervention, a standard lifestyle intervention (ie, DPP-based intervention), or an intensified lifestyle intervention for 12 months. For DPP, participants were recruited from 23 clinical study centres in the USA between July 31, 1996, and May 18, 1999, and randomly assigned to receive either a standard lifestyle intervention, metformin, or placebo. In both PLIS and DPP, only participants who were randomly assigned to receive lifestyle intervention or placebo and who lost at least 5% of their bodyweight were included in this analysis. Responders were defined as people who returned to normal fasting plasma glucose (FPG; <5·6 mmol/L), normal glucose tolerance (<7·8 mmol/L), and HbA1c less than 39 mmol/mol after 12 months of lifestyle intervention or placebo or control intervention. Non-responders were defined as people who had FPG, 2 h glucose, or HbA1c more than these thresholds. The main outcomes for this analysis were insulin sensitivity, insulin secretion, visceral adipose tissue (VAT), and intrahepatic lipid content (IHL) and were evaluated via linear mixed models.

FINDINGS

Of 1160 participants recruited to PLIS, 298 (25·7%) had weight loss of 5% or more of their bodyweight at baseline. 128 (43%) of 298 participants were responders and 170 (57%) were non-responders. Responders were younger than non-responders (mean age 55·6 years [SD 9·9] vs 60·4 years [8·6]; p<0·0001). The DPP validation cohort included 683 participants who lost at least 5% of their bodyweight at baseline. Of these, 132 (19%) were responders and 551 (81%) were non-responders. In PLIS, BMI reduction was similar between responders and non-responders (responders mean at baseline 32·4 kg/m2 [SD 5·6] to mean at 12 months 29·0 kg/m2 [4·9] vs non-responders 32·1 kg/m2 [5·9] to 29·2 kg/m2 [5·4]; p=0·86). However, whole-body insulin sensitivity increased more in responders than in non-responders (mean at baseline 291 mL/[min × m2], SD 60 to mean at 12 months 378 mL/[min × m2], 56 vs 278 mL/[min × m2], 62, to 323 mL/[min × m2], 66; p<0·0001), whereas insulin secretion did not differ within groups over time or between groups (responders mean at baseline 175 pmol/mmol [SD 64] to mean at 12 months 163·7 pmol/mmol [60·6] vs non-responders 158·0 pmol/mmol [55·6] to 154·1 pmol/mmol [56·2]; p=0·46). IHL decreased in both groups, without a difference between groups (responders mean at baseline 10·1% [SD 8·7] to mean at 12 months 3·5% [3·9] vs non-responders 10·3% [8·1] to 4·2% [4·2]; p=0·34); however, VAT decreased more in responders than in non-responders (mean at baseline 6·2 L [SD 2·9] to mean at 12 months 4·1 L [2·3] vs 5·7 L [2·3] to 4·5 L [2·2]; p=0·0003). Responders had a 73% lower risk of developing type 2 diabetes than non-responders in the 2 years after the intervention ended.

INTERPRETATION

By contrast to remission of type 2 diabetes, resolution of prediabetes was characterised by an improvement in insulin sensitivity and reduced VAT. Because return to normal glucose regulation (NGR) prevents development of type 2 diabetes, we propose the concept of remission of prediabetes in analogy to type 2 diabetes. We suggest that remission of prediabetes should be the primary therapeutic aim in individuals with prediabetes.

FUNDING

German Federal Ministry for Education and Research via the German Center for Diabetes Research; the Ministry of Science, Research and the Arts Baden-Württemberg; the Helmholtz Association and Helmholtz Munich; the Cluster of Excellence Controlling Microbes to Fight Infections; and the German Research Foundation.

Obesity and the risk of cardiometabolic diseases

The prevalence of obesity has reached pandemic proportions, and now approximately 25% of adults in Westernized countries have obesity. Recognized as a major health concern, obesity is associated with multiple comorbidities, particularly cardiometabolic disorders. In this Review, we present obesity as an evolutionarily novel condition, summarize the epidemiological evidence on its detrimental cardiometabolic consequences and discuss the major mechanisms involved in the association between obesity and the risk of cardiometabolic diseases. We also examine the role of potential moderators of this association, with evidence for and against the so-called 'metabolically healthy obesity phenotype', the 'fatness but fitness' paradox or the 'obesity paradox'. Although maintenance of optimal cardiometabolic status should be a primary goal in individuals with obesity, losing body weight and, particularly, excess visceral adiposity seems to be necessary to minimize the risk of cardiometabolic diseases.

Metabolically unhealthy phenotype in adults with normal weight: Is cardiometabolic health worse off when compared to adults with obesity?

The concept of metabolically healthy vs. unhealthy obese (MHO vs. MUO) was expanded to non-obese individuals as obesity-related comorbidities exist in a sub-group of normal weight (NW), i.e., MHNW vs. MUNW. It is unclear if MUNW differs from MHO with respect to cardiometabolic health.

PURPOSE

The purpose of this study was to compare cardiometabolic disease risk factors between MH vs. MU across weight status, NW, and obesity.

METHOD

A total of 8160 adults were included in the study from both the 2019 and 2020 Korean National Health and Nutrition Examination Surveys. Individuals with NW vs. obesity were further stratified as MH vs. MU by using AHA/NHLBI criterion for metabolic syndrome. A retrospective pair-matched analysis with respect to sex (male/female) and age ( ± 2 years) was performed to verify our total cohort analyses/results.

RESULTS

Despite a gradual increase in BMI and waist circumference from MHNW to MUNW to MHO to MUO, the surrogate estimates of insulin resistance and arterial stiffness were higher in MUNW vs. MHO. When compared to the MHNW, MUNW and MUO showed higher odds of hypertension (MUNW: 512%, MUO: 784%), dyslipidemia (MUNW: 210%, MUO: 245%), and diabetes (MUNW: 920%, MUO: 4012%), with no difference between MHNW and MHO.

CONCLUSION

Individuals with MUNW vs. MHO have greater vulnerability to cardiometabolic disease. Our data indicate that cardiometabolic risk is not solely dependent on adiposity, suggesting that early preventive efforts for chronic disease are needed for individuals with NW yet MU.

Evolution of Metabolic Phenotypes of Obesity in Coronary Patients after 5 Years of Dietary Intervention: From the CORDIOPREV Study

Background: Obesity phenotypes with different metabolic status have been described previously. We analyzed metabolic phenotypes in obese coronary patients during a 5-year follow-up, and examined the factors influencing this evolution. Methods: The CORDIOPREV study is a randomized, long-term secondary prevention study with two healthy diets: Mediterranean and low-fat. All obese patients were classified as either metabolically healthy obese (MHO) or metabolically unhealthy obese (MUO). We evaluated the changes in the metabolic phenotypes and related variables after 5 years of dietary intervention. Results: Initially, 562 out of the 1002 CORDIOPREV patients were obese. After 5 years, 476 obese patients maintained their clinical and dietary visits; 71.8% of MHO patients changed to unhealthy phenotypes (MHO-Progressors), whereas the MHO patients who maintained healthy phenotypes (MHO-Non-Progressors) lost more in terms of their body mass index (BMI) and had a lower fatty liver index (FLI-score) (p < 0.05). Most of the MUO (92%) patients maintained unhealthy phenotypes (MUO-Non-Responders), but 8% became metabolically healthy (MUO-Responders) after a significant decrease in their BMI and FLI-score, with improvement in all metabolic criteria. No differences were found among dietary groups. Conclusions: A greater loss of weight and liver fat is associated with a lower progression of the MHO phenotype to unhealthy phenotypes. Likewise, a marked improvement in these parameters is associated with regression from MUO to healthy phenotypes.

Socioeconomic disadvantages over the life-course and their influence on obesity among older Hong Kong Chinese adults

BACKGROUND

The life-course perspective on socioeconomic inequality in health is a burgeoning field of research. Nonetheless, the three classic life-course models (i.e. sensitive period, cumulative risk and social mobility models) have rarely been simultaneously applied to studies on obesity. Therefore, this study examined the associations of socioeconomic positions (SEPs) across life stages and their associated life-course models with both general and abdominal obesity.

METHODS

Face-to-face interviews were conducted among 1077 community-dwelling adults aged 50 or above during 2014-15 in Hong Kong. Experiences of poverty, educational attainment and deprivation of necessities represented respondents' SEP in childhood, early adulthood and late adulthood, respectively. General and abdominal obesity were defined as body mass index ≥25 kg m-2 and waist-to-height ratio >0.5. Multivariable modified Poisson regression with a robust error variance was performed.

RESULTS

Respondents with low childhood SEP tended to have reduced risk of general obesity [relative risk (RR) = 0.85; 95% confidence interval (CI) = 0.72-1.00], whereas those with low childhood SEP and low late-adulthood SEP tended to have increased risk of abdominal obesity (RR = 1.10; 95% CI = 1.00-1.21 and RR = 1.14; 95% CI = 1.03-1.26, respectively). Cumulative socioeconomic disadvantages showed a dose-response relationship with abdominal obesity. Also, those with upward socioeconomic mobility had lower risk of abdominal obesity, whereas those with downward socioeconomic mobility had greater risk.

CONCLUSIONS

Low SEP, especially in childhood, exerted contrasting effects on general and abdominal obesity among older Hong Kong Chinese adults. The three life-course models operated simultaneously in determining the risk of abdominal obesity, while support for cumulative risk and social mobility models was weak in general obesity.

Independent and combined associations of solid-fuel use and smoking with obesity among rural Chinese adults

Although solid-fuel use or smoking is associated with obesity measured by body mass index (BMI), research on their interactive effects on general and central obesity is limited. Data of 20,140 individuals in the Henan Rural Cohort Study was examined the independent and combined associations of solid-fuel use and smoking with prevalent obesity, which was measured by BMI, waist circumference (WC), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body fat percentage (BFP), and visceral fat index (VFI). Multiple adjusted logistic regression models showed that the OR (95% CI) of prevalent obesity measured by BMI associated with exposure to solid fuels alone or with smoking was 0.78 (0.70, 0.86) or 0.46 (0.32, 0.66), compared with neither smoking nor solid-fuel exposure. Similar results had been found in other obese anthropometric indices and in the results of linear regression analysis. The results indicated that solid-fuel use and smoking have a synergistic effect on reduction in obesity indices. The effects of household air pollution from solid-fuel use and smoking on obesity should be considered when exploring the influencing factors of obesity.

COVID-19 and non-alcoholic fatty liver disease: Two intersecting pandemics

BACKGROUND

Initial evidence from China suggests that most vulnerable subjects to COVID-19 infection suffer from pre-existing illness, including metabolic abnormalities. The pandemic characteristics and high-lethality rate of COVID-19 infection have raised concerns about interactions between virus pathobiology and components of the metabolic syndrome.

METHODS

We harmonized the information from the recent existing literature on COVID-19 acute pandemic and mechanisms of damage in non-alcoholic fatty liver disease (NAFLD), as an example of chronic (non-communicable) metabolic pandemic.

RESULTS

COVID-19-infected patients are more fragile with underlying metabolic illness, including hypertension, cardiovascular disease, type 2 diabetes, chronic lung diseases (e.g. asthma, chronic obstructive pulmonary disease and emphysema) and metabolic syndrome. During metabolic abnormalities, expansion of metabolically active fat ('overfat condition') parallels chronic inflammatory changes, development of insulin resistance and accumulation of fat in configuring NAFLD. The deleterious interplay of inflammatory pathways chronically active in NAFLD and acutely in COVID-19-infected patients, can explain liver damage in a subgroup of patients and might condition a worse outcome in metabolically compromised NAFLD patients. In a subgroup of patients with NAFLD, the underlying liver fibrosis might represent an additional and independent risk factor for severe COVID-19 illness, irrespective of metabolic comorbidities.

CONCLUSIONS

NAFLD can play a role in the outcome of COVID-19 illness due to frequent association with comorbidities. Initial evidences suggest that increased liver fibrosis in NAFLD might affect COVID-19 outcome. In addition, long-term monitoring of post-COVID-19 NAFLD patients is advisable, to document further deterioration of liver damage. Further studies are required in this field.

Adherence to a plant-based diet in relation to adipose tissue volumes and liver fat content

BACKGROUND

Better adherence to plant-based diets has been linked to lower risk of metabolic diseases but the effect on abdominal fat distribution and liver fat content is unclear.

OBJECTIVES

We aimed to examine the association between different plant-based diet indices and measures of abdominal fat distribution and liver fat content.

METHODS

In a population-based sample of 578 individuals from Northern Germany (57% male, median age 62 y), diet was assessed with a validated FFQ and an overall, a healthy, and an unhealthy plant-based diet index were derived. Participants underwent MRI to assess volumes of visceral and subcutaneous abdominal adipose tissue and liver signal intensity (LSI), a measure of liver fat content. Fatty liver disease (FLD) was defined as log LSI ≥3.0. Cross-sectional associations of the plant-based diet indices with visceral and subcutaneous abdominal fat volumes, LSI, and FLD were assessed in linear and logistic regression analyses. The most comprehensive model adjusted for age, sex, education, smoking, alcohol, physical activity, energy intake, diabetes, hyperlipidemia, and BMI.

RESULTS

Higher overall and healthy plant-based diet indices both revealed statistically significant associations with lower visceral and subcutaneous abdominal adipose tissue volumes and with lower odds of FLD in multivariable-adjusted models without BMI. Upon additional adjustment for BMI, only the association of the healthy plant-based diet with visceral adipose tissue remained statistically significant (per 10-point higher healthy plant-based diet index, percentage change in visceral adipose tissue: -4.9%, 95% CI: -8.6%, -2.0%). None of the plant-based diet indices was associated with LSI. The unhealthy plant-based diet index was unrelated to any of the abdominal or liver fat parameters.

CONCLUSIONS

Adherence to healthy plant-based diets was associated with lower visceral adipose tissue. None of the other examined associations remained statistically significant after adjustment for BMI.

The independent role of deprivation in abdominal obesity beyond income poverty. A population-based household survey in Chinese adults

BACKGROUND

Individual-level deprivation takes into account the non-monetary aspects of poverty that neither income poverty nor socio-economic factors could fully capture; however, it has rarely been considered in existing studies on social inequality in obesity. Therefore, we examined the associations of deprivation, beyond income poverty, with both general and abdominal obesity.

METHODS

A territory-wide two-stage stratified random sample of 2282 community-dwelling Hong Kong adults was surveyed via face-to-face household interviews between 2014 and 2015. Deprivation was assessed by a Deprivation Index specific to the Hong Kong population. General obesity was defined as body mass index (BMI) ≥ 25 kg/m2, while abdominal obesity was defined as waist circumference (WC) ≥ 90 cm/80 cm for male/female. Multivariable binary logistic regressions were performed.

RESULTS

Deprivation was independently associated with abdominal obesity (odds ratios (OR) = 1.68; 95% confidence intervals (CI): 1.27-2.22); however, no significant association was found with general obesity (OR=1.03; CI: 0.77-1.38). After additional adjustment for BMI, deprivation remained strongly associated with abdominal obesity (OR=2.00; CI: 1.41-2.83); and after further adjustment for WC, deprivation had a marginal inverse association with general obesity (OR=0.72; CI: 0.51-1.01).

CONCLUSIONS

Deprivation is an important risk factor of abdominal obesity and plays a critical role in capturing the preferential abdominal fat deposition beyond income poverty.

Association of Dimethylguanidino Valeric Acid With Partial Resistance to Metabolic Health Benefits of Regular Exercise

Importance

Metabolic responses to exercise training are variable. Metabolite profiling may aid in the clinical assessment of an individual's responsiveness to exercise interventions.

Objective

To investigate the association between a novel circulating biomarker of hepatic fat, dimethylguanidino valeric acid (DMGV), and metabolic health traits before and after 20 weeks of endurance exercise training.

Design, Setting, and Participants

This study involved cross-sectional and longitudinal analyses of the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) Family Study, a 20-week, single-arm endurance exercise clinical trial performed in multiple centers between 1993 and 1997. White participants with sedentary lifestyles who were free of cardiometabolic disease were included. Metabolomic tests were performed using a liquid chromatography, tandem mass spectrometry method on plasma samples collected before and after exercise training in the HERITAGE study. Metabolomics and data analysis were performed from August 2017 to May 2018.

Exposures

Plasma DMGV levels.

Main Outcome and Measures

The association between DMGV levels and measures of body composition, plasma lipids, insulin, and glucose homeostasis before and after exercise training.

Results

Among the 439 participants included in analyses from HERITAGE, the mean (SD) age was 36 (15) years, 228 (51.9%) were female, and the median (interquartile range) body mass index was 25 (22-28). Baseline levels of DMGV were positively associated with body fat percentage, abdominal visceral fat, very low-density lipoprotein cholesterol, and triglycerides, and inversely associated with insulin sensitivity, low-density lipoprotein cholesterol, high-density lipoprotein size, and high-density lipoprotein cholesterol (range of β coefficients, 0.17-0.46 [SEs, 0.026-0.050]; all P < .001, after adjusting for age and sex). After adjusting for age, sex, and baseline traits, baseline DMGV levels were positively associated with changes in small high-density lipoprotein particles (β, 0.14 [95% CI, 0.05-0.23]) and inversely associated with changes in medium and total high-density lipoprotein particles (β, -0.15 [95% CI, -0.24 to -0.05] and -0.19 [95% CI, -0.28 to -0.10], respectively), apolipoprotein A1 (β, -0.14 [95% CI, -0.23 to -0.05]), and insulin sensitivity (β, -0.13; P = 3.0 × 10-3) after exercise training.

Conclusions and Relevance

Dimethylguanidino valeric acid is an early marker of cardiometabolic dysfunction that is associated with attenuated improvements in lipid traits and insulin sensitivity after exercise training. Levels of DMGV may identify individuals who require additional therapies beyond guideline-directed exercise to improve their metabolic health.

Metabolically healthy obesity: facts and fantasies

Although obesity is typically associated with metabolic dysfunction and cardiometabolic diseases, some people with obesity are protected from many of the adverse metabolic effects of excess body fat and are considered "metabolically healthy." However, there is no universally accepted definition of metabolically healthy obesity (MHO). Most studies define MHO as having either 0, 1, or 2 metabolic syndrome components, whereas many others define MHO using the homeostasis model assessment of insulin resistance (HOMA-IR). Therefore, numerous people reported as having MHO are not metabolically healthy, but simply have fewer metabolic abnormalities than those with metabolically unhealthy obesity (MUO). Nonetheless, a small subset of people with obesity have a normal HOMA-IR and no metabolic syndrome components. The mechanism(s) responsible for the divergent effects of obesity on metabolic health is not clear, but studies conducted in rodent models suggest that differences in adipose tissue biology in response to weight gain can cause or prevent systemic metabolic dysfunction. In this article, we review the definition, stability over time, and clinical outcomes of MHO, and discuss the potential factors that could explain differences in metabolic health in people with MHO and MUO - specifically, modifiable lifestyle factors and adipose tissue biology. Better understanding of the factors that distinguish people with MHO and MUO can produce new insights into mechanism(s) responsible for obesity-related metabolic dysfunction and disease.

Novel Insights into the Pathogenesis and Management of the Metabolic Syndrome

The metabolic syndrome, by definition, is not a disease but is a clustering of individual metabolic risk factors including abdominal obesity, hyperglycemia, hypertriglyceridemia, hypertension, and low high-density lipoprotein cholesterol levels. These risk factors could dramatically increase the prevalence of type 2 diabetes and cardiovascular disease. The reported prevalence of the metabolic syndrome varies, greatly depending on the definition used, gender, age, socioeconomic status, and the ethnic background of study cohorts. Clinical and epidemiological studies have clearly demonstrated that the metabolic syndrome starts with central obesity. Because the prevalence of obesity has doubly increased worldwide over the past 30 years, the prevalence of the metabolic syndrome has markedly boosted in parallel. Therefore, obesity has been recognized as the leading cause for the metabolic syndrome since it is strongly associated with all metabolic risk factors. High prevalence of the metabolic syndrome is not unique to the USA and Europe and it is also increasing in most Asian countries. Insulin resistance has elucidated most, if not all, of the pathophysiology of the metabolic syndrome because it contributes to hyperglycemia. Furthermore, a major contributor to the development of insulin resistance is an overabundance of circulating fatty acids. Plasma fatty acids are derived mainly from the triglycerides stored in adipose tissues, which are released through the action of the cyclic AMP-dependent enzyme, hormone sensitive lipase. This review summarizes the latest concepts in the definition, pathogenesis, pathophysiology, and diagnosis of the metabolic syndrome, as well as its preventive measures and therapeutic strategies in children and adolescents.

Non-Alcoholic Fatty Liver Disease in Non-Obese Individuals: Prevalence, Pathogenesis and Treatment

Non-alcoholic fatty liver disease (NAFLD) parallels comorbidities such as metabolic syndrome, dyslipidaemia or diabetes. Although NAFLD is very prevalent in overweight-obese individuals (i.e. body mass index ≥25 kg/m2), recent studies point to the presence of NAFLD in non-obese individuals, for both the Asian (<25 kg/m2) and Caucasian (<30 kg/m2) populations. This paper discusses the pathogenic pathways and current treatment options of NAFLD in non-obese populations. In this respect, non-obese subjects also need to undergo the medical screening for NAFLD. Across the scientific community, we aim to promote the advancement of knowledge in this emerging field.

Multi-disciplinary weight management compared to routine care in youth with obesity: what else should be monitored?

PURPOSE

Efficacy of multi-disciplinary weight management (MDM) in youth has not been compared to their routine care.

OBJECTIVES

To compare body mass index z-score (zBMI) and blood test (lab) changes (Δ) in youth before and after MDM and to correlate bio-impedance analysis (BIA) and lab measurements.

METHODS

We compared zBMI Δ (from referring providers' records), within 3 months prior to MDM, to monthly zBMI Δ after MDM, in a retrospective cohort of youth at a tertiary MDM center. BIA and lab measurements after 6 months, MDM were compared to baseline.

RESULTS

We reviewed 316 records (12.9 ± 3.5 years, 49% males, 104.8 ± 35.1 kgs). The pre-MDM zBMI Δ (0.02 ± 0.1) was reversed after MDM (-0.03 ± 0.09, visit 2, P < 0.001). The zBMI Δ progressed on follow-up (-0.14 ± 0.05, visit 6). Baseline BIA components correlated with Homeostatic Model Assessment of Insulin resistance (HOMA-IR), triglycerides, and systolic blood pressure. HbA1c, HOMA-IR, and liver functions significantly improved on follow-up. MDM participation showed progressive attrition and dropped to 11.6% at visit 6.

CONCLUSION

MDM in youth resulted in zBMI and lab improvements compared to their pre-MDM measurements. BIA provided additional outcome measures that correlated with metabolic markers. MDM follow-up was limited by the progressive participant drop-out. Behavioral economic strategies are needed to improve adherence.

Comparison of Abdominal Obesity and Fatty Liver and Their Association with Insulin Resistance and Metabolic Syndrome in Chinese Adults

OBJECTIVE

The purpose of this study was to explore the similarities and differences between nonalcoholic fatty liver (FL) disease (NAFLD) and abdominal obesity in their association with insulin resistance and metabolic syndrome (MetS).

METHODS

The Survey on Prevalence in East China for Metabolic Diseases and Risk Factors (SPECT-China) is a population-based survey of Chinese adults. A total of 9,685 participants (median age, 53 years; interquartile range, 44-63) were grouped into four categories by waist circumference (WC) and NAFLD status: NWC/FL(-), NWC/FL(+), HWC/FL(-), and HWC/FL(+) [FL(-), without NAFLD; FL(+), with NAFLD; HWC, higher WC; NWC, normal WC]. Logistic regression models were used to obtain the odds ratios as estimates of the associations between different categories and MetS.

RESULTS

Male participants with HWC/FL(-) had higher homeostatic model assessment for insulin resistance scores than subjects with NWC/FL(+), but female subjects showed the opposite results. Compared with NWC/FL(+), HWC was associated with an increased likelihood of blood pressure disorder and a decreased likelihood of triglyceride and blood glucose disorders in men, but in women, HWC was associated with only a lower likelihood of triglyceride disorder. Despite these differences, patients with NWC/FL(+) and HWC/FL(-) had almost equally serious degrees of metabolic disorders (MetS z score).

CONCLUSIONS

There are significant differences between sexes regarding the association between NAFLD and abdominal obesity status and MetS components.

Fecal and blood microbiota profiles and presence of nonalcoholic fatty liver disease in obese versus lean subjects

Pathophysiological background in different phenotypes of nonalcoholic fatty liver disease (NAFLD) remains to be elucidated. The aim was to investigate the association between fecal and blood microbiota profiles and the presence of NAFLD in obese versus lean subjects. Demographic and clinical data were reviewed in 268 health checkup examinees, whose fecal and blood samples were available for microbiota analysis. NAFLD was diagnosed with ultrasonography, and subjects with NAFLD were further categorized as obese (body mass index (BMI) ≥25) or lean (BMI <25). Fecal and blood microbiota communities were analyzed by sequencing of the V3-V4 domains of the 16S rRNA genes. Correlation between microbiota taxa and NAFLD was assessed using zero-inflated Gaussian mixture models, with adjustment of age, sex, and BMI, and Bonferroni correction. The NAFLD group (n = 76) showed a distinct bacterial community with a lower biodiversity and a far distant phylotype compared with the control group (n = 192). In the gut microbiota, the decrease in Desulfovibrionaceae was associated with NAFLD in the lean NAFLD group (log2 coefficient (coeff.) = -2.107, P = 1.60E-18), but not in the obese NAFLD group (log2 coeff. = 1.440, P = 1.36E-04). In the blood microbiota, Succinivibrionaceae showed opposite correlations in the lean (log2 coeff. = -1.349, P = 5.34E-06) and obese NAFLD groups (log2 coeff. = 2.215, P = 0.003). Notably, Leuconostocaceae was associated with the obese NAFLD in the gut (log2 coeff. = -1.168, P = 0.041) and blood (log2 coeff. = -2.250, P = 1.28E-10). In conclusion, fecal and blood microbiota profiles showed different patterns between subjects with obese and lean NAFLD, which might be potential biomarkers to discriminate diverse phenotypes of NAFLD.

Visceral adipose tissue tracks more closely with metabolic dysfunction than intrahepatic triglyceride in lean Asians without diabetes

Increased visceral adipose tissue (VAT) and intrahepatic triglyceride (IHTG) are important risk factors for the development of type 2 diabetes in subjects with obesity. The relative contribution of these ectopic fat depots to cardiometabolic risk differs between populations, depends on the degree of obesity and the level of cardiorespiratory fitness, and is difficult to dissect because VAT and IHTG typically covary. The aim of this study was to evaluate the effect of an isolated increase in VAT or IHTG on insulin sensitivity and insulin secretion in apparently healthy normal-weight Asian subjects. Total body fat (dual X-ray absorptiometry), VAT and IHTG (magnetic resonance), insulin sensitivity (4-h hyperinsulinemic-euglycemic clamp), beta cell responsivity and insulin secretion rate (3-h mixed meal with mathematical modeling), and cardiorespiratory fitness (maximal oxygen consumption [V̇o2max]) were evaluated in groups of lean subjects with low or high VAT (687 ± 94 vs. 1,279 ± 197 ml, matched for IHTG; n = 13 each) and low or high IHTG (1.7 ± 0.3 vs. 6.7 ± 2.0%, matched for VAT; n = 15 each). All groups were matched for age, sex, total body fat, and V̇o2max. High-VAT subjects had ~25% lower insulin sensitivity, ~20%–40% greater beta cell responsivity and insulin secretion rate, ~35% greater fasting triglyceride concentration, and ~40% lower adiponectin concentration than low-VAT subjects (all P < 0.05). No differences were observed between low-IHTG and high-IHTG subjects. Accumulation of excess fat in the intra-abdominal area is more strongly associated with metabolic dysfunction than accumulation of liver fat in lean Asians without diabetes.

NEW & NOTEWORTHY It is not known whether metabolic abnormalities in Asians without obesity track more closely with visceral or liver fat. We found an isolated increase in visceral fat was associated with reduced insulin sensitivity, greater insulin secretion, greater triglyceride, and lower adiponectin concentrations; no differences were observed with an isolated increase in liver fat. These results suggest that visceral fat is a better correlate of metabolic dysfunction than liver fat in Asians without obesity.

Embrionary way to create a fatty liver in portal hypertension

Portal hypertension in the rat by triple partial portal vein ligation produces an array of splanchnic and systemic disorders, including hepatic steatosis. In the current review these alterations are considered components of a systemic inflammatory response that would develop through three overlapping phenotypes: The neurogenic, the immune and the endocrine. These three inflammatory phenotypes could resemble the functions expressed during embryonic development of mammals. In turn, the inflammatory phenotypes would be represented in the embryo by two functional axes, that is, a coelomic-amniotic axis and a trophoblastic yolk-sac or vitelline axis. In this sense, the inflammatory response developed after triple partial portal vein ligation in the rat would integrate both functional embryonic axes on the liver interstitial space of Disse. If so, this fact would favor the successive development of steatosis, steatohepatitis and fibrosis. Firstly, these recapitulated embryonic functions would produce the evolution of liver steatosis. In this way, this fat liver could represent a yolk-sac-like in portal hypertensive rats. After that, the systemic recapitulation of these embryonic functions in experimental prehepatic portal hypertension would consequently induce a gastrulation-like response in which a hepatic wound healing reaction or fibrosis occur. In conclusion, studying the mechanisms involved in embryonic development could provide key results for a better understanding of the nonalcoholic fatty liver disease etiopathogeny.

Association of Non-alcoholic Fatty Liver Disease with Metabolic Syndrome Independently of Central Obesity and Insulin Resistance

Non-alcoholic fatty liver disease (NAFLD) is an emerging chronic liver disease that may lead to liver cirrhosis and hepatocellular carcinoma. We aimed to determine the association between the prevalence of metabolic syndrome (MetS) and NAFLD severity using semi-quantitative ultrasonography (US). A total of 614 participants were recruited from the community. NAFLD was evaluated according to the ultrasonographic Fatty Liver Indicator (US-FLI), which is a semi-quantitative liver ultrasound score. Insulin resistance was estimated with the homeostasis model assessment index for insulin resistance (HOMA-IR). NAFLD and MetS were found in 53.7 and 17.3% of the participants, respectively. Linear relationships were found between the severity of NAFLD and waist circumference, fasting glucose, HOMA-IR, triglycerides, HDL-C and blood pressure. After adjusting for confounding factors, i.e., body mass index and HOMA-IR, the odds ratios for MetS were 3.64 (95% confidence interval (CI): 1.5-8.83) for those with mild NAFLD and 9.4 (95% CI: 3.54-24.98) for those with moderate-to-severe NAFLD compared to those without NAFLD. The combination of the HOMA-IR and US-FLI scores better differentiated MetS than the HOMA-IR alone. In addition to obesity, the severity of NAFLD and the HOMA-IR both play important roles in MetS. Whether NAFLD is a component of MetS warrants further research.

Physical Activity and Sedentary Behavior in Metabolically Healthy versus Unhealthy Obese and Non-Obese Individuals - The Maastricht Study

Background

Both obesity and the metabolic syndrome are associated with increased risk of cardiovascular diseases and type 2 diabetes. Although both frequently occur together in the same individual, obesity and the metabolic syndrome can also develop independently from each other. The (patho)physiology of “metabolically healthy obese” (i.e. obese without metabolic syndrome) and “metabolically unhealthy non-obese” phenotypes (i.e. non-obese with metabolic syndrome) is not fully understood, but physical activity and sedentary behavior may play a role.

Objective

To examine objectively measured physical activity and sedentary behavior across four groups: I) “metabolically healthy obese” (MHO); II) “metabolically unhealthy obese” (MUO); III)”metabolically healthy non-obese” (MHNO); and IV) “metabolically unhealthy non-obese” (MUNO).

Methods

Data were available from 2,449 men and women aged 40–75 years who participated in The Maastricht Study from 2010 to 2013. Participants were classified into the four groups according to obesity (BMI≥30kg/m²) and metabolic syndrome (ATPIII definition). Daily activity was measured for 7 days with the activPAL physical activity monitor and classified as time spent sitting, standing, and stepping.

Results

In our study population, 562 individuals were obese. 19.4% of the obese individuals and 72.7% of the non-obese individuals was metabolically healthy. After adjustments for age, sex, educational level, smoking, alcohol use, waking time, T2DM, history of CVD and mobility limitation, MHO (n = 107) spent, per day, more time stepping (118.2 versus 105.2 min; p<0.01) and less time sedentary (563.5 versus 593.0 min., p = 0.02) than MUO (n = 440). In parallel, MHNO (n = 1384) spent more time stepping (125.0 versus 115.4 min; p<0.01) and less time sedentary (553.3 versus 576.6 min., p<0.01) than MUNO (n = 518).

Conclusion

Overall, the metabolically healthy groups were less sedentary and more physically active than the metabolically unhealthy groups. Therefore, physical activity and sedentary time may partly explain the presence of the metabolic syndrome in obese as well as non-obese individuals.

Lean NAFLD: An Underrecognized Outlier

Nonalcoholic fatty liver disease (NAFLD) is commonly diagnosed in obese or overweight individuals. However, lean individuals with NAFLD are not rare but represent one significant end of the phenotypic spectrum of NAFLD. Although initial observations between obese and lean NAFLD reveal some metabolic parallels, these associations vary widely given differences in study populations and metabolic parameters assessed. The role of body composition in risk assessment is significant and incompletely assessed during most clinical encounters. Recent multinational investigation reveals an increased mortality in lean individuals with NASH. Many aspects of lean NAFLD need further exploration including epidemiology, clinical risk assessment, histologic changes unique to lean NAFLD, genetic and pathophysiologic mechanisms predisposing at risk individuals, natural history and treatment strategies in this underrecognized population.

Liver Fat Assessed With CT Relates to MRI Markers of Incipient Brain Injury in Middle-Aged to Elderly Overweight Persons

OBJECTIVE

Obesity has been related to structural brain abnormalities. Increasing evidence suggests that accumulation of fat in the liver is an important determinant of cardiometabolic complications of obesity. The purpose of this study was to investigate the association between CT-assessed liver-to-spleen attenuation ratio as a measure of liver steatosis and MRI-assessed brain tissue integrity in middle-aged to elderly persons.

SUBJECTS AND METHODS

CT and MRI were performed on 213 participants (114 women, 99 men; mean age, 65 ± 7 years). Brain tissue integrity was assessed by magnetization transfer imaging. Linear regression analysis was adjusted for age, sex, vascular risk factors, and total body fat estimated from bioelectrical impedance analysis.

RESULTS

Seventy-nine participants had normal weight (body mass index [BMI], 18.5-24.9), and 134 were overweight (BMI ≥ 25). Significant interaction was found between liver-to-spleen ratio and BMI (p = 0.001). In the overweight group, liver fat was associated with reduced brain tissue integrity in both gray matter (standardized β = 0.22; 95% CI, 0.07-0.36) and white matter (standardized β = 0.31; 95% CI, 0.15-0.45). These associations were not found in the normal weight group (gray matter standardized β = -0.08; 95% CI, -0.33 to 0.16; white matter standardized β = -0.09; 95% CI, -0.36-0.14).

CONCLUSION

The results indicate that liver fat assessed with CT relates to MRI markers of incipient brain injury in middle-aged to elderly overweight persons.

Predictive value of serum dihomo-γ-linolenic acid level and estimated Δ-5 desaturase activity in patients with hepatic steatosis

BACKGROUND

Hepatic steatosis is considered one of the features of metabolic syndrome (MetS). Polyunsaturated fatty acid (PUFA) metabolism is modulated in obesity. However, it has yet to be fully elucidated whether a serum PUFA profile is associated with hepatic steatosis.

OBJECTIVE

We aimed to clarify the relationship between a serum PUFA profile and liver lipid content.

METHODS

A cross-sectional study was conducted on 288 patients with dyslipidemia, diabetes, or coronary artery disease on statin therapy. Several PUFAs were measured, including eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), dihomo-γ-linolenic acid (DGLA) and arachidonic acid (AA) in serum lipids, and Δ-5 desaturase (D5D) activity was estimated by AA to DGLA ratio. Abdominal computed tomography (CT) measured visceral fat area (VFA) and the ratio of CT attenuation for liver to spleen (L/S).

RESULTS

The L/S ratio showed significant correlations with serum DGLA level and D5D activity (p<0.0001 for both). Serum DGLA level and D5D activity were significantly correlated with body mass index (BMI) or VFA, and with Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) (p<0.0001 for all). Multivariate logistic analysis revealed that a high DGLA level or low D5D activity was a significant determinant for hepatic steatosis (p<0.0001 for both) independent of BMI and HOMA-IR. ROC analysis revealed that they significantly enhanced the value of MetS-related factors in predicting hepatic steatosis (p<0.05 for both).

CONCLUSIONS

A high DGLA level and low D5D activity in serum lipids may be useful markers predicting hepatic steatosis incrementally to MetS-related conventional factors.

CT-based compartmental quantification of adipose tissue versus body metrics in colorectal cancer patients

PURPOSE

While obesity is considered a prognostic factor in colorectal cancer (CRC), there is increasing evidence that not simply body mass index (BMI) alone but specifically abdominal fat distribution is what matters. As part of the ColoCare study, this study measured the distribution of adipose tissue compartments in CRC patients and aimed to identify the body metric that best correlates with these measurements as a useful proxy for adipose tissue distribution.

MATERIALS AND METHODS

In 120 newly-diagnosed CRC patients who underwent multidetector computed tomography (CT), densitometric quantification of total (TFA), visceral (VFA), intraperitoneal (IFA), retroperitoneal (RFA), and subcutaneous fat area (SFA), as well as the M. erector spinae and psoas was performed to test the association with gender, age, tumor stage, metabolic equivalents, BMI, waist-to-height (WHtR) and waist-to-hip ratio (WHR).

RESULTS

VFA was 28.8 % higher in men (p_VFA<0.0001) and 30.5 % higher in patients older than 61 years (p_VFA<0.0001). WHtR correlated best with all adipose tissue compartments (r_VFA=0.69, r_TFA=0.84, p<0.0001) and visceral-to-subcutaneous-fat-ratio (VFR, r_VFR=0.22, p=<0.05). Patients with tumor stages III/IV showed significantly lower overall adipose tissue than I/II. Increased M. erector spinae mass was inversely correlated with all compartments.

CONCLUSION

Densitometric quantification on CT is a highly reproducible and reliable method to show fat distribution across adipose tissue compartments. This distribution might be best reflected by WHtR, rather than by BMI or WHR.

KEY POINTS

• Densitometric quantification of adipose tissue on CT is highly reproducible and reliable. • Waist-to-height ratio better correlates with adipose tissue compartments and VFR than BMI or waist-to-hip ratio. • Men have higher a higher visceral fat area than women. • Patients older than 61 years have higher visceral fat area. • Patients with tumor stages III/IV have significantly lower adipose tissue than those in stages I/II.

Mice lacking GPR3 receptors display late-onset obese phenotype due to impaired thermogenic function in brown adipose tissue

We report an unexpected link between aging, thermogenesis and weight gain via the orphan G protein-coupled receptor GPR3. Mice lacking GPR3 and maintained on normal chow had similar body weights during their first 5 months of life, but gained considerably more weight thereafter and displayed reduced total energy expenditure and lower core body temperature. By the age of 5 months GPR3 KO mice already had lower thermogenic gene expression and uncoupling protein 1 protein level and showed impaired glucose uptake into interscapular brown adipose tissue (iBAT) relative to WT littermates. These molecular deviations in iBAT of GPR3 KO mice preceded measurable differences in body weight and core body temperature at ambient conditions, but were coupled to a failure to maintain thermal homeostasis during acute cold challenge. At the same time, the same cold challenge caused a 17-fold increase in Gpr3 expression in iBAT of WT mice. Thus, GPR3 appears to have a key role in the thermogenic response of iBAT and may represent a new therapeutic target in age-related obesity.

Beyond central adiposity: liver fat and visceral fat area are associated with metabolic syndrome in morbidly obese patients

BACKGROUND

Despite its widespread clinical use, both body mass index (BMI) and waist circumference have been reported as inaccurate methods to measure abdominal obesity. The main objective of this study was to determine the relation between visceral fat area and fatty liver infiltration with the expression of metabolic syndrome (MS) in morbidly obese patients.

METHODS

We recruited a random selection of 100 morbidly obese patients on pre-operative evaluation for bariatric surgery. A pre-operative CT slice at L4-L5 level, was performed to measure visceral fat and at T12 level to measure hepatic attenuation.

RESULTS

Patients with MS had lower hepatic attenuation values (median 49.9 vs 55.5HU; p = .018) and had more VAT (242 vs 172 cm(2);p = .001). Conventional measures (BMI: p = .729 and waist circumference: p = .356), were not useful in discriminating morbidly obese patients with MS. By multivariable logistic regression, fatty liver infiltration (OR = 5.3; p = .03) and age (OR = 1.08; p = .04) were the only factors independently related to the presence of MS. MS prevalence was 100%, 71% and 55%, respectively for patients with both fatty liver and visceral adiposity; one; or none of this findings (AUC - .715; p = .016).

CONCLUSION

CT scan seems to measure 2 important markers of MS: visceral adiposity and hepatic fatty infiltration. In morbidly obese patients, both visceral adiposity and hepatic fatty infiltration increase the risk for the presence of MS.

Cortisol in tissue and systemic level as a contributing factor to the development of metabolic syndrome in severely obese patients

CONTEXT

Adrenal and extra-adrenal cortisol production may be involved in the development of metabolic syndrome (MetS).

OBJECTIVE

To investigate the activity of the hypothalamic-pituitary-adrenal (HPA) axis and the expression of HSD11B1, nuclear receptor subfamily 3, group C, member 1 (glucocorticoid receptors) α (NR3C1α) and β (NR3C1β) in the liver, subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) of severely obese patients with and without MetS.

METHODS

The study included 37 severely obese patients (BMI ≥ 40 kg/m(2)), 19 with MetS (MetS+ group) and 18 without (MetS- group), studied before and during bariatric surgery. Before the day of surgery, urinary free cortisol (UFC) and diurnal variation of serum and salivary cortisol were estimated. During surgery, biopsies of the liver, VAT and SAT were obtained. The expression of HSD11B1, NR3C1α and NR3C1β was evaluated by RT-PCR.

RESULTS

UFC and area under the curve for 24-h profiles of serum and salivary cortisol were lower in the MetS- group. In the MetS- group, mRNA levels of HSD11B1 in liver exhibited a negative correlation with liver NR3C1α (LNR3C1α) and VAT expression of HSD11B1 was lower than the MetS+ group.

CONCLUSIONS

We observed a downregulation of the NR3C1α expression and lower VAT mRNA levels of HSD11B1 in the MetS- group, indicating a lower selective tissue cortisol production and action that could protect these patients from the metabolic consequences of obesity. In the MetS- group, a lower activity of the HPA axis was also detected. Taken together, cortisol in tissue and systematic level might play a role in the development of MetS in severely obese patients.

Non-alcoholic fatty liver disease and obesity: Biochemical, metabolic and clinical presentations

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in the world. Presentation of the disease ranges from simple steatosis to non-alcoholic steatohepatitis (NASH). NAFLD is a hepatic manifestation of metabolic syndrome that includes central abdominal obesity along with other components. Up to 80% of patients with NAFLD are obese, defined as a body mass index (BMI) > 30 kg/m². However, the distribution of fat tissue plays a greater role in insulin resistance than the BMI. The large amount of visceral adipose tissue (VAT) in morbidly obese (BMI > 40 kg/m²) individuals contributes to a high prevalence of NAFLD. Free fatty acids derived from VAT tissue, as well as from dietary sources and de novo lipogenesis, are released to the portal venous system. Excess free fatty acids and chronic low-grade inflammation from VAT are considered to be two of the most important factors contributing to liver injury progression in NAFLD. In addition, secretion of adipokines from VAT as well as lipid accumulation in the liver further promotes inflammation through nuclear factor kappa B signaling pathways, which are also activated by free fatty acids, and contribute to insulin resistance. Most NAFLD patients are asymptomatic on clinical presentation, even though some may present with fatigue, dyspepsia, dull pain in the liver and hepatosplenomegaly. Treatment for NAFLD and NASH involves weight reduction through lifestyle modifications, anti-obesity medication and bariatric surgery. This article reviews the available information on the biochemical and metabolic phenotypes associated with obesity and fatty liver disease. The relative contribution of visceral and liver fat to insulin resistance is discussed, and recommendations for clinical evaluation of affected individuals is provided.

Overfeeding polyunsaturated and saturated fat causes distinct effects on liver and visceral fat accumulation in humans

Excess ectopic fat storage is linked to type 2 diabetes. The importance of dietary fat composition for ectopic fat storage in humans is unknown. We investigated liver fat accumulation and body composition during overfeeding saturated fatty acids (SFAs) or polyunsaturated fatty acids (PUFAs). LIPOGAIN was a double-blind, parallel-group, randomized trial. Thirty-nine young and normal-weight individuals were overfed muffins high in SFAs (palm oil) or n-6 PUFAs (sunflower oil) for 7 weeks. Liver fat, visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue (SAT), total adipose tissue, pancreatic fat, and lean tissue were assessed by magnetic resonance imaging. Transcriptomics were performed in SAT. Both groups gained similar weight. SFAs, however, markedly increased liver fat compared with PUFAs and caused a twofold larger increase in VAT than PUFAs. Conversely, PUFAs caused a nearly threefold larger increase in lean tissue than SFAs. Increase in liver fat directly correlated with changes in plasma SFAs and inversely with PUFAs. Genes involved in regulating energy dissipation, insulin resistance, body composition, and fat-cell differentiation in SAT were differentially regulated between diets, and associated with increased PUFAs in SAT. In conclusion, overeating SFAs promotes hepatic and visceral fat storage, whereas excess energy from PUFAs may instead promote lean tissue in healthy humans.

Effect of resistance training on non-alcoholic fatty-liver disease a randomized-clinical trial

AIM: To evaluate the effect of resistance training (RT) on non alcoholic liver disease (NAFLD) patients.

METHODS: A randomized clinical trial enrolling NAFLD patients without secondary liver disease (e.g., without hepatitis B virus, hepatitis C virus or excessive alcohol consumption). Patients were randomly allocated either to RT, three times weekly, for 3 mo or a control arm consisting of home stretching. The RT included leg press, chest press, seated rowing, latissimus pull down etc. with 8-12 repetitions, 3 sets for each exercise, for a total duration of 40 min. Hepatic ultrasound, fasting blood tests, anthropometrics and body composition by dual energy X-ray absorptiometry were assessed. At baseline and follow-up, patients filled out a detailed semi-quantitative food frequency questionnaire reporting their habitual nutritional intake. Steatosis was quantified by the hepatorenal-ultrasound index (HRI) representing the ratio between the brightness level of the liver and the right kidney. The HRI has been previously demonstrated to be highly reproducible and was validated against liver biopsy and proton magnetic resonance spectroscopy.

RESULTS: Eighty two patients with primary NAFLD were randomized to receive 3 mo of either RT or stretching. After dropout or exclusion from analysis because of protocol violation (weight change > 3 kg), thirty three patients in the RT arm and 31 in the stretching arm completed the study per protocol. All baseline characteristics were similar for the two treatment groups with respect to demographics, anthropometrics and body composition, blood tests and liver steatosis on imaging. HRI score was reduced significantly in the RT arm as compared to the stretching arm (-0.25 ± 0.37 vs -0.05 ± 0.28, P = 0.017). The RT arm had a significantly higher reduction in total, trunk and android fat with increase in lean body mass. There was no correlation between the reduction in HRI in the RT arm and weight change during the study, but it was positively correlated with the change in trunk fat (r = 0.37, P = 0.048). The RT arm had a significant reduction in serum ferritin and total cholesterol. There was no significant difference between arms in dietary changes and these did not correlate with HRI change.

CONCLUSION: Three months RT improves hepatic fat content accompanied by favorable changes in body composition and ferritin. RT may serve as a complement to treatment of NAFLD.

Association of liver enzymes and computed tomography markers of liver steatosis with familial longevity

OBJECTIVE

Familial longevity is marked by enhanced peripheral but not hepatic insulin sensitivity. The liver has a critical role in the pathogenesis of hepatic insulin resistance. Therefore we hypothesized that the extent of liver steatosis would be similar between offspring of long-lived siblings and control subjects. To test our hypothesis, we investigated the extent of liver steatosis in non-diabetic offspring of long-lived siblings and age-matched controls by measuring liver enzymes in plasma and liver fat by computed tomography (CT).

RESEARCH DESIGN AND METHODS

We measured nonfasting alanine transaminase (ALT), aspartate aminotransferase (AST), and Υ-glutamyl transferase (GGT) in 1625 subjects (736 men, mean age 59.1 years) from the Leiden Longevity Study, comprising offspring of long-lived siblings and partners thereof. In a random subgroup, fasting serum samples (n = 230) were evaluated and CT was performed (n = 268) for assessment of liver-spleen (L/S) ratio and the prevalence of moderate-to-severe non-alcoholic fatty liver disease (NAFLD). Linear mixed model analysis was performed adjusting for age, gender, body mass index, smoking, use of alcohol and hepatotoxic medication, and correlation of sibling relationship.

RESULTS

Offspring of long-lived siblings had higher nonfasting ALT levels as compared to control subjects (24.3 mmol/L versus 23.2 mmol/L, p = 0.03), while AST and GGT levels were similar between the two groups. All fasting liver enzyme levels were similar between the two groups. CT L/S ratio and prevalence of moderate-to-severe NAFLD was similar between groups (1.12 vs 1.14, p = 0.25 and 8% versus 8%, p = 0.91, respectively).

CONCLUSIONS

Except for nonfasting levels of ALT, which were slightly higher in the offspring of long-lived siblings compared to controls, no differences were found between groups in the extent of liver steatosis, as assessed with liver biochemical tests and CT. Thus, our data indicate that the extent of liver steatosis is similar between offspring of long-lived siblings and control subjects.

Hepatic steatosis is associated with surgical-site infection after hepatic and colorectal surgery

BACKGROUND

Obesity and increased visceral fat deposits are important risk factors for surgical-site infection (SSI). Interestingly, a potential role of hepatic steatosis on complications after extrahepatic surgery remains unknown. The aim of the present study was to investigate the impact of hepatic steatosis on SSI in patients that underwent open abdominal surgery.

METHODS

A total of 231 patients that underwent either liver (n = 116) or colorectal (n = 115) resection and received preoperative contrast-enhanced computed tomography scans were retrospectively investigated. Signal attenuation of the liver parenchyma was measured on computed tomography scans to assess hepatic steatosis.

RESULTS

More SSIs (including types 1, 2, and 3) were found in the group with hepatic steatosis (56/118 [47.5%]) compared with the control group (30/113 [26.6%]; P = .001). Patients with hepatic steatosis showed greater median body mass index than patients without hepatic steatosis (26.6 kg/m(2) [range 16.8-47.0 kg/m(2)] vs 23.2 kg/m(2) [15.9-32.7 kg/m(2)]; P < .001). Patients with hepatic steatosis experienced longer median operation times (297 minutes [52-708 minutes] vs 240 minutes [80-600 minutes]; P = .003). In a multivariate analysis, hepatic steatosis was identified as an independent risk factor for SSI in patients undergoing hepatic (odds ratio 10.33 [95% confidence interval 1.19-89.76]; P = .03) or colorectal (odds ratio 6.67 [95% confidence interval 1.12-39.33]; P = .04) operation.

CONCLUSION

Hepatic steatosis is associated with SSI after hepatic and colorectal operation.

Pre- and postnatal nutrition in sheep affects β-cell secretion and hypothalamic control

Maternal undernutrition increases the risk of type 2 diabetes and metabolic syndrome later in life, particularly upon postnatal exposure to a high-energy diet. However, dysfunctions of, for example, the glucose-insulin axis are not readily detectable by conventional tests early in life, making it difficult to identify individuals at risk. Thus, other methods are required. We hypothesised that prenatally undernourished individuals (but not postnatally overnourished ones) are adapted to a life with limited food availability, which would be evident under conditions reflecting starvation, stress and short-term abundance of food. In this study, twin-pregnant sheep were fed diets meeting 100% (NORM) or 50% (LOW) of energy and protein requirements during the last trimester. Twin offspring were fed either a normal moderate (CONV) diet or a high-carbohydrate-high-fat (HCHF) diet from 3 days to 6 months of age (approximately puberty) and the same moderate diet thereafter until 2 years of age (young adulthood; only females), resulting in four groups: NORM-CONV, LOW-CONV, NORM-HCHF and LOW-HCHF. At the age of 6 months and 2 years respectively, they were subjected to fasting and propionate (nutrient abundance) and adrenalin challenges. At 6 months of age, postnatal HCHF diet exposure caused metabolic alterations, reflecting hypertriglyceridaemia and altered pancreatic β-cell secretion. Irrespective of postnatal diet, prenatal undernutrition was found to be associated with unexpected endocrine responses of leptin, IGF1 and cortisol during fasting (lack of or the opposite response compared with the controls) in 2-year-old adults. In conclusion, a HCHF diet interfered with β-cell function, whereas maternal undernutrition did not lead to any changes in the LOW offspring, except to abnormal hormone responses, suggesting that fetal programming interferes with hypothalamic integration of important endocrine axis.

Lean NASH: distinctiveness and clinical implication

INTRODUCTION

Non-alcoholic fatty liver (NAFL) in the absence of overweight and/or obesity, defined by the anthropometric parameter, body mass index (BMI), has been designated as 'lean NASH.' While maintaining a close pathophysiological link with metabolic syndrome (MS) and insulin resistance (IR), the presence of subtle alterations in measures of total body and regional adiposity not exceeding the designed cut-offs, are hallmarks of 'lean NASH.'

MATERIAL AND METHODS

Available literature related to non-alcoholic steatohepatitis (NASH) in lean or non-obese individuals and its pathogenesis in general published in English language journals till the time of manuscript preparation were reviewed and critically analysed.

ANALYSIS

Being a closely related but variant phenotype of NASH, its features metabolically resemble the well-characterized entity 'metabolically obese normal weight (MONW)' individuals. Apart from total body adiposity, distribution of fat in different body compartments has assumed greater pathophysiologic relevance in characterizing 'lean NASH'. Detection of NASH in stringently defined non-obese individuals, by both BMI and waist circumference indices, indicates existence of a subset of NASH in which fat compartmentalization at ectopic sites is not picked up by the anthropometric yardsticks used. Volume [Quantity] and biological behavior of the visceral and deep subcutaneous adipose tissues contribute to this variant of NASH in non-obese subjects. Genetic predisposition to IR and MS along with the environmental influences like childhood nutritional status, dietary composition and gut microbiome possibly play pathogenetic role.

CONCLUSION

The most important concern is in the principles of nomenclature within syndromes where clinical dissimilarities exist despite biological similarities. Till a uniformly acceptable pathophysiological and/or etiology-based classification emerges, the term "lean NASH" would continue to provide us an opportunity to ponder over and refine this subset of fatty liver in non-obese people and potentially significant liver disease.

Ultrasound evaluation and correlates of fatty liver disease: a population study in a Mediterranean area

BACKGROUND

The aim of this study was to evaluate the distribution of fatty liver-nonalcoholic (NAFL) and alcoholic (AFL)-and its association with metabolic syndrome and its components in a population sample from a Mediterranean area.

METHODS

A sample of 2974 subjects (1679 males, 1295 females, age range 30-89 years) was randomly drawn from the population of a town in southern Italy. The survey visit included a validated semiquantitative food frequency questionnaire, anthropometric measurements, a blood sample taken in the morning after overnight fasting, as well as abdominal ultrasound examination to evaluate liver fat with a standardized scoring system. The 2001 National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) definition of the metabolic syndrome was adopted.

RESULTS

In this Mediterranean population, where alcohol intake is mostly as wine with meals, NAFL is present in 36.8% of men and 25.7% of women and AFL in 13.8% of men and 5.5% of women. NAFL and AFL are associated with metabolic syndrome and its characteristics, body mass index (BMI), and visceral and subcutaneous fat (in AFL subjects, only in women) measured by ultrasound. Stratifying by BMI and controlling for confounders (age, height, smoking habit, and alcohol consumption), in overweight and obese subjects, liver and visceral fat are associated with the metabolic syndrome both in men and women and subcutaneous fat only in women. In normal weight subjects, only liver fat in men is associated with the metabolic syndrome.

CONCLUSIONS

Fatty liver is highly prevalent in this Mediterranean population and is associated with metabolic syndrome in overweight and obese men and women as well as in men with normal BMI.

Normal weight obesity is associated with metabolic syndrome and insulin resistance in young adults from a middle-income country

Objective

This population-based birth cohort study examined whether normal weight obesity is associated with metabolic disorders in young adults in a middle-income country undergoing rapid nutrition transition.

Design and Methods

The sample involved 1,222 males and females from the 1978/79 Ribeirão Preto birth cohort, Brazil, aged 23–25 years. NWO was defined as body mass index (BMI) within the normal range (18.5–24.9 kg/m²) and the sum of subscapular and triceps skinfolds above the sex-specific 90th percentiles of the study sample. It was also defined as normal BMI and % BF (body fat) >23% in men and >30% in women. Insulin resistance (IR), insulin sensitivity and secretion were based on the Homeostasis Model Assessment (HOMA) model.

Results

In logistic models, after adjusting for age, sex and skin colour, NWO was significantly associated with Metabolic Syndrome (MS) according to the Joint Interim Statement (JIS) definition (Odds Ratio OR = 6.83; 95% Confidence Interval CI 2.84–16.47). NWO was also associated with HOMA2-IR (OR = 3.81; 95%CI 1.57–9.28), low insulin sensitivity (OR = 3.89; 95%CI 2.39–6.33), and high insulin secretion (OR = 2.17; 95%CI 1.24–3.80). Significant associations between NWO and some components of the MS were also detected: high waist circumference (OR = 8.46; 95%CI 5.09–14.04), low High Density Lipoprotein cholesterol (OR = 1.65; 95%CI 1.11–2.47) and high triglyceride levels (OR = 1.93; 95%CI 1.02–3.64). Most estimates changed little after further adjustment for early and adult life variables.

Conclusions

NWO was associated with MS and IR, suggesting that clinical assessment of excess body fat in normal-BMI individuals should begin early in life even in middle-income countries.

Eicosanoids in metabolic syndrome

Chronic persistent inflammation plays a significant role in disease pathology of cancer, cardiovascular disease, and metabolic syndrome (MetS). MetS is a constellation of diseases that include obesity, diabetes, hypertension, dyslipidemia, hypertriglyceridemia, and hypercholesterolemia. Nonalcoholic fatty liver disease (NAFLD) is associated with many of the MetS diseases. These metabolic derangements trigger a persistent inflammatory cascade, which includes production of lipid autacoids (eicosanoids) that recruit immune cells to the site of injury and subsequent expression of cytokines and chemokines that amplify the inflammatory response. In acute inflammation, the transcellular synthesis of antiinflammatory eicosanoids resolve inflammation, while persistent activation of the autacoid-cytokine-chemokine cascade in metabolic disease leads to chronic inflammation and accompanying tissue pathology. Many drugs targeting the eicosanoid pathways have been shown to be effective in the treatment of MetS, suggesting a common linkage between inflammation, MetS and drug metabolism. The cross-talk between inflammation and MetS seems apparent because of the growing evidence linking immune cell activation and metabolic disorders such as insulin resistance, dyslipidemia, and hypertriglyceridemia. Thus modulation of lipid metabolism through either dietary adjustment or selective drugs may become a new paradigm in the treatment of metabolic disorders. This review focuses on the mechanisms linking eicosanoid metabolism to persistent inflammation and altered lipid and carbohydrate metabolism in MetS.

11β-Hydroxysteroid dehydrogenase type 1: relevance of its modulation in the pathophysiology of obesity, the metabolic syndrome and type 2 diabetes mellitus

Recent evidence strongly argues for a pathogenic role of glucocorticoids and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in obesity and the metabolic syndrome, a cluster of risk factors for atherosclerotic cardiovascular disease and type 2 diabetes mellitus (T2DM) that includes insulin resistance (IR), dyslipidaemia, hypertension and visceral obesity. This has been partially prompted not only by the striking clinical resemblances between the metabolic syndrome and Cushing's syndrome (a state characterized by hypercortisolism that associates with metabolic syndrome components) but also from monogenic rodent models for the metabolic syndrome (e.g. the leptin-deficient ob/ob mouse or the leptin-resistant Zucker rat) that display overall increased secretion of glucocorticoids. However, systemic circulating glucocorticoids are not elevated in obese patients and/or patients with metabolic syndrome. The study of the role of 11β-HSD system shed light on this conundrum, showing that local glucocorticoids are finely regulated in a tissue-specific manner at the pre-receptor level. The system comprises two microsomal enzymes that either activate cortisone to cortisol (11β-HSD1) or inactivate cortisol to cortisone (11β-HSD2). Transgenic rodent models, knockout (KO) for HSD11B1 or with HSD11B1 or HSD11B2 overexpression, specifically targeted to the liver or adipose tissue, have been developed and helped unravel the currently undisputable role of the enzymes in metabolic syndrome pathophysiology, in each of its isolated components and in their prevention. In the transgenic HSD11B1 overexpressing models, different features of the metabolic syndrome and obesity are replicated. HSD11B1 gene deficiency or HSD11B2 gene overexpression associates with improvements in the metabolic profile. In face of these demonstrations, research efforts are now being turned both into the inhibition of 11β-HSD1 as a possible pharmacological target and into the role of dietary habits on the establishment or the prevention of the metabolic syndrome, obesity and T2DM through 11β-HSD1 modulation. We intend to review and discuss 11β-HSD1 and obesity, the metabolic syndrome and T2DM and to highlight the potential of its inhibition for therapeutic or prophylactic approaches in those metabolic diseases.

Visceral adiposity and hepatic steatosis at abdominal CT: association with the metabolic syndrome

OBJECTIVE

Visceral adiposity and hepatic steatosis may correlate with the metabolic syndrome but are not currently among the diagnostic criteria. We evaluated these features at unenhanced MDCT.

MATERIALS AND METHODS

Semiautomated measurements of subcutaneous fat area, visceral fat area, and visceral fat percentage were obtained at the umbilical level at unenhanced MDCT of 474 adults (217 men, 257 women; mean age, 58.3 years) using a dedicated application (Fat Assessment Tool, EBW version 4.5). Unenhanced liver attenuation was also recorded. Metabolic syndrome was defined using the criteria proposed by the International Diabetes Federation in 2005.

RESULTS

The prevalence of metabolic syndrome was 35.0% (76/217) among men and 35.8% (92/257) among women. The area under the receiver operating characteristic curve (AUC) for visceral fat area was 0.830 (95% CI, 0.784-0.867) in men and 0.887 (0.848-0.918) in women (p = 0.162). The AUC for subcutaneous fat area was 0.865 (0.823-0.899) in men and 0.762 (0.711-0.806) in women (p = 0.024). The AUC for visceral fat percentage was 0.527 (0.472-0.581) in men and 0.820 (0.774-0.859) in women (p < 0.001). The AUC for liver attenuation was 0.706 (0.653-0.754). Thresholds of subcutaneous fat area greater than 204 cm(2) in men, visceral fat area greater than 70 cm(2) in women, and liver attenuation less than 50 HU yielded a sensitivity and specificity of 80.3% and 83.7%; 83.7% and 80.0%; and 22.0% and 96.7%, respectively. Visceral fat area was elevated in 55% of patients without metabolic syndrome (11/20) but with a documented cardiovascular event or complication and in 32.1% of patients with a body mass index of 30 kg/m(2) or less.

CONCLUSION

Accumulation of visceral fat was the best predictor for metabolic syndrome in women. Unexpectedly, the percentage of visceral fat was a poor predictor for metabolic syndrome in men and subcutaneous fat area was best. Decreased liver attenuation was insensitive but was highly specific for metabolic syndrome. The implications of these sex-specific differences and the relationship of fat-based CT measures to cardiovascular risk warrant further investigation.

Visceral fat volume predicts new-onset type 2 diabetes in patients with chronic hepatitis C

Ninety seven patients with chronic hepatitis C (CHC) and 72 with non-alcoholic fatty liver disease (NAFLD) were enrolled. Increased visceral fat area (VFA) was associated with high values of HbA1c. The variables associated with a high risk of new-onset diabetes had a VFA>101 cm(2) in CHC, but not in NAFLD.

[Identification and quantification of fat compartments with CT and MRI and their importance]

In addition to being overweight, as defined by the BMI, the distribution, composition and biological activity of adipose tissue are key elements in the cardiovascular risk stratification of patients. Several non-invasive techniques have been developed to quantify local fat depots, whereby computed tomography (CT) and magnetic resonance imaging (MRI) are the most important. In general adipose tissue is subdivided into subcutaneous and visceral compartments and although both are associated with cardiovascular risk factors and disease, visceral fat has on average a stronger association and a clearly higher biological activity independent of traditional risk factors. This maybe explained by the higher endocrine activity and secretion of pro-inflammatory cytokines by visceral fat. Especially pericardial adipose tissue, a local visceral fat depot surrounding the coronary arteries, is associated with the presence, extent and severity of coronary artery disease. However, several other local fat depots have been identified and associations with various diseases have been established. This article gives an overview over the current methods for the identification and quantification of local fat depots and summarizes the hypothesized and known associations. Furthermore, it gives an overview of the potential significance of individual local fat depots for cardiovascular risk stratification.

The contribution of vitamin A to autocrine regulation of fat depots

Morbidity and mortality associated with increased white fat accumulation in visceral fat depots have focused attention on the pathways regulating the development of this tissue during embryogenesis, in adulthood, and while under the influence of obesogenic diets. Adipocytes undergo clonal expansion, differentiation (adipogenesis) and maturation through a complex network of transcriptional factors, most of which are expressed at similar levels in visceral and subcutaneous fat. Rigorous research attempts to unfold the pathways regulating expression and activity of adipogenic transcription factors that act in a fat-depot-specific manner. Peroxisome proliferator-activated receptor-γ (PPARγ) is the master regulator of adipogenesis, and is expressed at higher levels in subcutaneous than in visceral depots. PPARγ expression in adipogenesis is mediated by CCAAT/enhancer binding proteins (C/EBPs) and several transcription factors acting in conjunction with C/EBPs, although alternative pathways through zinc-finger protein-423 (ZFP423) transcription factor are sufficient to induce PPARγ expression and adipogenesis. Vitamin A and its metabolites, retinaldehyde and retinoic acid, are transcriptionally-active molecules. Retinoic acid is generated from retinaldehyde in adipose tissue by the aldehyde dehydrogenase-1 family of enzymes (Aldh1). In this review, we discuss the role of Aldh1 enzymes in the generation of retinoic acid during adipogenesis, in the regulation of the transcriptional network of PPARγ in a fat-depot-specific manner, and the important contribution of this autocrine pathway in the development of visceral obesity. This article is part of a Special Issue entitled Retinoid and Lipid Metabolism.