Ectopic fat, insulin resistance and non-alcoholic fatty liver disease. Proc Nutr Soc. 2013;72:412-419. [PMID: 23668723 DOI: 10.1017/s0029665113001249]

Effect of uric acid on lipid metabolism assessed via restricted cubic splines: A new insight

Background

Hyperuricemia can promote both blood lipids and non-alcoholic fatty liver disease (NAFLD). However, the role of the entire uric acid (UA) span, especially low concentrations below hyperuricemia, on lipid metabolism remains unclear.

Methods

A cross-sectional study was designed. Data on the age, sex, UA, triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) of 1977 participants, who underwent physical examination, were collected. NAFLD and non-alcoholic fatty pancreas disease (NAFPD) were diagnosed using abdominal ultrasound. Restricted cubic splines (RCS) linear regression model was used to evaluate the effect of the UA span on TG, TC, HDL, and LDL, respectively. RCS logistic regression model was employed to evaluate the effect of the UA span on NAFLD and NAFPD.

Results

RCS linear regression model showed that TG was negatively correlated with UA at first, then exhibiting a positive correlation. Meanwhile, HDL was positively correlated with UA at first, then negatively correlated. There was a positive linear correlation between TC and UA (P for nonlinear = 0.578) and a positive nonlinear correlation between LDL and UA (P for nonlinear = 0.021). RCS logistic regression model showed that NAFLD and NAFPD were negatively correlated with UA at first and then positively correlated with UA.

Conclusion

our study showed that the entire UA span has a J-shaped effect on some lipids, NAFLD, and NAFPD. Besides, TG and HDL, compared with TC or LDL, may better reflect the status of NAFLD and NAFPD.

Systemic impacts of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) on heart, muscle, and kidney related diseases

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously known as non-alcoholic fatty liver disease (NAFLD), is the most common liver disorder worldwide, with an estimated global prevalence of more than 31%. Metabolic dysfunction-associated steatohepatitis (MASH), formerly known as non-alcoholic steatohepatitis (NASH), is a progressive form of MASLD characterized by hepatic steatosis, inflammation, and fibrosis. This review aims to provide a comprehensive analysis of the extrahepatic manifestations of MASH, focusing on chronic diseases related to the cardiovascular, muscular, and renal systems. A systematic review of published studies and literature was conducted to summarize the findings related to the systemic impacts of MASLD and MASH. The review focused on the association of MASLD and MASH with metabolic comorbidities, cardiovascular mortality, sarcopenia, and chronic kidney disease. Mechanistic insights into the concept of lipotoxic inflammatory "spill over" from the MASH-affected liver were also explored. MASLD and MASH are highly associated (50%-80%) with other metabolic comorbidities such as impaired insulin response, type 2 diabetes, dyslipidemia, hypertriglyceridemia, and hypertension. Furthermore, more than 90% of obese patients with type 2 diabetes have MASH. Data suggest that in middle-aged individuals (especially those aged 45-54), MASLD is an independent risk factor for cardiovascular mortality, sarcopenia, and chronic kidney disease. The concept of lipotoxic inflammatory "spill over" from the MASH-affected liver plays a crucial role in mediating the systemic pathological effects observed. Understanding the multifaceted impact of MASH on the heart, muscle, and kidney is crucial for early detection and risk stratification. This knowledge is also timely for implementing comprehensive disease management strategies addressing multi-organ involvement in MASH pathogenesis.

Effects of GLP-1 receptor agonists on the degree of liver fibrosis and CRP in non-alcoholic fatty liver disease and non-alcoholic steatohepatitis: A systematic review and meta-analysis

BACKGROUND

Based on the rapidly growing global burden of non-alcoholic fatty liver disease (NAFLD) or steatohepatitis (NASH), in order to evaluate the efficacy of glucagon-like peptide-1 receptor agonists (GLP-1RAs) in the treatment of NAFLD or NASH this paper presents a systematic review and meta-analysis of randomized controlled trials(RCTs).

METHODS

In this systematic review and meta-analysis, We searched PubMed, Medline, Web of Science and The Cochrane Library databases. All randomized controlled trials involving GLP-1RAs and NAFLD or NASH were collected since the database was established. A meta-analysis of proportions was done with the generalised linear mixed model. Continuous variables were represented by Mean and Standard Deviation (SD), and binary variable were represented by Relative Risk (RR) and 95% Confidence Interval (CI) as effect indicators. The research results were presented by Revman 5.4. This study is registered with PROSPERO (CRD42023390735).

FINDING

We included 16 placebo-controlled or active drug-controlled randomized controlled trials (involving 2178 patients) that used liraglutide, exenatide, dulaglutide, or semaglutie in the treatment of NAFLD or NASH, as measured by liver biopsy or imaging techniques. This study found that the effect of GLP-1RAs on histologic resolution of NASH with no worsening of liver fibrosis (n=2 RCTs; WMD:4.08, 95%CI 2.54-6.56, p < 0.00001) has statistically significant. At the same time, GLP-1RAs affected CRP (n = 7 RCTs; WMD:-0.41, 95% CI-0.78 to -0.04, p =0.002) and other serological indicators were significantly improved.

CONCLUSION

This study evaluated the efficacy of GLP-1RAs in patients with NAFLD and NASH. These results suggest that GLP-1RAs may be a potential and viable therapeutic approach as a targeted agent to intervene in disease progression of NAFLD and NASH.

Gender perspective on the association between liver enzyme markers and non-alcoholic fatty liver disease: insights from the general population

Objective

Every distinct liver enzyme biomarker exhibits a strong correlation with non-alcoholic fatty liver disease (NAFLD). This study aims to comprehensively analyze and compare the associations of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyl transferase (GGT) with NAFLD from a gender perspective.

Methods

This study was conducted on 6,840 females and 7,411 males from the NAGALA cohort. Multivariable logistic regression analysis was used to compare the associations between liver enzyme markers and NAFLD in both genders, recording the corresponding adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Receiver operating characteristic (ROC) curves were used to evaluate the accuracy of individual liver enzyme markers and different combinations of them in identifying NAFLD.

Results

Liver enzyme markers ALT, AST, and GGT were all independently associated with NAFLD and exhibited significant gender differences (All P-interaction<0.05). In both genders, ALT exhibited the most significant association with NAFLD, with adjusted standardized ORs of 2.19 (95% CI: 2.01-2.39) in males and 1.60 (95% CI: 1.35-1.89) in females. Additionally, ROC analysis showed that ALT had significantly higher accuracy in identifying NAFLD than AST and GGT in both genders (Delong P-value < 0.05), and the accuracy of ALT in identifying NAFLD in males was higher than that in females [Area under the ROC curve (AUC): male 0.79, female 0.77]. Furthermore, out of the various combinations of liver enzymes, ALT+GGT showed the highest accuracy in identifying NAFLD in both genders, with AUCs of 0.77 (95% CI: 0.75-0.79) in females and 0.79 (95% CI: 0.78-0.81) in males.

Conclusion

Our study revealed significant gender differences in the associations of the three commonly used liver enzyme markers with NAFLD. In both genders, the use of ALT alone may be the simplest and most effective tool for screening NAFLD, especially in males.

Association between different modalities of insulin administration and metabolic dysfunction-associated fatty liver disease in adults with type 1 diabetes mellitus

AIM

We examined whether different insulin administration modalities, i.e., multiple daily injections (MDI) or continuous subcutaneous insulin infusion (CSII by insulin pumps), are differently associated with the risk of having metabolic dysfunction-associated fatty liver disease (MAFLD), with or without coexisting significant liver fibrosis (assessed by validated non-invasive biomarkers), in adults with type 1 diabetes mellitus (T1DM).

METHODS

We conducted a retrospective, multicenter, cross-sectional study involving 1,417 adult individuals with established T1DM treated with MDI or CSII. We calculated hepatic steatosis index (HSI) and fibrosis (FIB)-4 index for non-invasively detecting MAFLD (defined by HSI >36), with or without coexisting significant fibrosis (defined by FIB-4 index ≥ 1.3 or <1.3, respectively).

RESULTS

Compared to the MDI group (n = 1,161), insulin-pump users (n = 256; 18.1%) were more likely to be younger (mean age: 40 vs. 48 years, P < 0.001), had better glycemic control (mean hemoglobin A1c: 7.7%  vs. 7.9%, P = 0.025) and a markedly lower prevalence of MAFLD with coexisting significant fibrosis (2.7%  vs. 8.1%, P = 0.010), but a comparable prevalence of MAFLD without fibrosis. In multinomial logistic regression analysis, CSII therapy was associated with a ∼70%-lower risk of MAFLD with significant fibrosis (unadjusted odds ratio 0.32, 95% confidence interval 0.14-0.70; P = 0.004), but this association was no longer significant after adjustment for age, hemoglobin A1c and other potential confounders.

CONCLUSION

The lower prevalence of MAFLD with coexisting significant fibrosis we observed in adults with T1DM using CSII therapy, compared to those using MDI therapy, is primarily mediated by inter-group differences in age.

Association of body fat and muscle tissue parameters with fatty liver disease identified by ultrasound

AIMS

To examine the association between body fat and muscle parameters and FLD in individuals of Chinese descent.

METHODS

A total of 515 participants who underwent routine check-ups between November 2019 and August 2021 were reviewed. Based on ultrasound performance, the subjects were categorized into the non-FLD group and the FLD group. The prevalence of FLD in sex subgroups was analyzed using logistic regression to calculate the odds ratios (ORs) of body composition parameters with adjustment for confounders.

RESULTS

A total of 262 males and 253 females aged 20-84 years were reviewed. In both males and females, higher fat mass index (FMI) (OR: 1.989 for males vs. 1.389 for females), fat mass percent (FM%) (OR: 1.253 for males vs. 1.149 for females), visceral adipose tissue (VAT) (OR: 1.002 for males vs. 1.002 for females), and body mass index (BMI) (OR: 1.530 for males vs. 1.247 for females)were associated with increased ORs of FLD while higher lean mass percent (LM%) (OR: 0.839 for males vs. 0.856 for females)was associated with decreased ORs of FLD. Despite accounting for confounding factors, the associations remained present. Logistic regression of the quartiles of the indices showed associations with the prevalence of FLD. The trends still existed even after adjusting for confounders.

CONCLUSION

Independently of age, lipid profiles and other confounders, lower VAT, FM, FMI, FM% and BMI tended to be associated with a lower prevalence of FLD, while lower LM% trended to be associated with a higher prevalence of FLD in both sexes of the general population.

Increased risk of incident diabetes in patients with MAFLD not meeting the criteria for NAFLD

We aimed to compare the risk of incident diabetes according to fatty liver disease (FLD) definition, focusing on the comparison between those who met criteria for either metabolic dysfunction-associated fatty liver disease (MAFLD) or nonalcoholic fatty liver disease (NAFLD) but not the other. This was a 5.0-year (interquartile range, 2.4-8.2) retrospective longitudinal cohort study of 21,178 adults who underwent at least two serial health checkup examinations. The presence of hepatic steatosis was determined by abdominal ultrasonography at the first health examination. Cox proportional hazard analyses were used to compare the risk of incident diabetes among five groups. Incident diabetes cases occurred in 1296 participants (6.1%). When non-FLD without metabolic dysfunction (MD) group was set as a reference, the risk of incident diabetes increased in the order of NAFLD-only, non-FLD with MD, both FLD, and MAFLD-only groups. The presence of excessive alcohol consumption and/or hepatitis B virus (HBV)/hepatitis C virus (HCV) infection, FLD, and MD synergistically increased the risk of incident diabetes. MAFLD-only group showed a greater increase in incidence of diabetes than non-FLD with MD and NAFLD-only groups. The interaction among excessive alcohol consumption, HBV/HCV infection, MD, and hepatic steatosis on the development of diabetes should not be overlooked.

Association between the lean nonalcoholic fatty liver disease and risk of incident type 2 diabetes in a healthy population of Northwest China: a retrospective cohort study with a 2-year follow-up period

Aims

We aimed to explore the metabolic features of lean nonalcoholic fatty liver disease (Lean-NAFLD) and its association with the risk of incident type 2 diabetes in young and middle-aged people.

Methods

We conducted a retrospective cohort study of 3001 participants who were enrolled in a health check-up program from January 2018 to December 2020 in the Health Management Center of Karamay People's Hospital. The age, sex, height, weight, body mass index (BMI), blood pressure, waist circumference (WC), fasting plasma glucose (FPG), lipid profiles, serum uric acid and alanine aminotransferase (ALT) of the subjects were collected. The cutoff point of BMI for lean nonalcoholic fatty liver disease is <25 kg/m². A COX proportional hazard regression model was used to analyze the risk ratio of lean nonalcoholic fatty liver disease to type 2 diabetes mellitus.

Results

Lean NAFLD participants had many metabolic abnormalities, such as overweight and obesity with nonalcoholic fatty liver disease. Compared with lean participants without nonalcoholic fatty liver disease, the fully adjusted hazard ratio (HR) for lean participants with nonalcoholic fatty liver disease was 3.83 (95% CI 2.02-7.24, p<0.01). In the normal waist circumference group (man<90cm, woman<80 cm), compared with lean participants without NAFLD, the adjusted hazard ratios (HRs) of incident type 2 diabetes for lean participants with NAFLD and overweight or obese participants with NAFLD were 1.93 (95% CI 0.70-5.35, p>0.05) and 4.20 (95% CI 1.44-12.22, p<0.05), respectively. For excess waist circumference (man≥90 cm, woman ≥80 cm) compared with lean participants without NAFLD, the adjusted hazard ratios (HRs) of incident type 2 diabetes for lean participants with NAFLD and overweight or obese participants with NAFLD were 3.88 (95% CI 1.56-9.66, p<0.05) and 3.30 (95% CI 1.52-7.14, p<0.05), respectively.

Conclusion

Abdominal obesity is the strongest risk factor for type 2 diabetes in lean nonalcoholic fatty liver disease.

Fatty Acid Excess Dysregulates CARF to Initiate the Development of Hepatic Steatosis

CARF (CDKN2AIP) regulates cellular fate in response to various stresses. However, its role in metabolic stress is unknown. We found that fatty livers from mice exhibit low CARF expression. Similarly, overloaded palmitate inhibited CARF expression in HepG2 cells, suggesting that excess fat-induced stress downregulates hepatic CARF. In agreement with this, silencing and overexpressing CARF resulted in higher and lower fat accumulation in HepG2 cells, respectively. Furthermore, CARF overexpression lowered the ectopic palmitate accumulation in HepG2 cells. We were interested in understanding the role of hepatic CARF and underlying mechanisms in the development of NAFLD. Mechanistically, transcriptome analysis revealed that endoplasmic reticulum (ER) stress and oxidative stress pathway genes significantly altered in the absence of CARF. IRE1α, GRP78, and CHOP, markers of ER stress, were increased, and the treatment with TUDCA, an ER stress inhibitor, attenuated fat accumulation in CARF-deficient cells. Moreover, silencing CARF caused a reduction of GPX3 and TRXND3, leading to oxidative stress and apoptotic cell death. Intriguingly, CARF overexpression in HFD-fed mice significantly decreased hepatic steatosis. Furthermore, overexpression of CARF ameliorated the aberrant ER function and oxidative stress caused by fat accumulation. Our results further demonstrated that overexpression of CARF alleviates HFD-induced insulin resistance assessed with ITT and GTT assay. Altogether, we conclude that excess fat-induced reduction of CARF dysregulates ER functions and lipid metabolism leading to hepatic steatosis.

Mechanisms and possible hepatoprotective effects of glucagon-like peptide-1 receptor agonists and other incretin receptor agonists in non-alcoholic fatty liver disease

Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are incretins that stimulate insulin secretion from pancreatic β cells in response to food ingestion. Modified GLP-1 and GIP peptides are potent agonists for their incretin receptors, and some evidence shows that the dual GLP-1 and GIP receptor agonist tirzepatide is effective in promoting marked weight loss. GLP-1 receptor agonists signal in the CNS to suppress appetite, increase satiety, and thereby decrease calorie intake, but many other effects of incretin signalling have been recognised that are relevant to the treatment of non-alcoholic fatty liver disease (NAFLD). This Review provides an overview of the literature supporting the notion that endogenous incretins and incretin-receptor agonist treatments are important not only for decreasing risk of developing NAFLD, but also for treating NAFLD and NAFLD-related complications. We discuss incretin signalling and related incretin-receptor agonist treatments, mechanisms in key relevant tissues affecting liver disease, and clinical data from randomised controlled trials. Finally, we present future perspectives in this rapidly developing field of research and clinical medicine.

Novel nutraceutical supplements with yeast β-glucan, prebiotics, minerals, and Silybum marianum (silymarin) ameliorate obesity-related metabolic and clinical parameters: A double-blind randomized trial

Purpose

It is known that obesity has a multifactorial etiology that involves genetic and environmental factors. The WHO estimates the worldwide prevalence of 1.9 billion overweight adults and more than 650 million people with obesity. These alarming data highlight the high and growing prevalence of obesity and represent a risk factor for the development and aggravation of other chronic diseases, such as nonalcoholic fatty liver disease (NAFLD) that is frequently considered the hepatic outcome of type 2 diabetes. The use of non-pharmacological therapies such as food supplements, nutraceuticals, and natural integrative therapies has grown as an alternative tool for obesity-related diseases compared to conventional medications. However, it is a still little explored research field and lacks scientific evidence of therapeutic effectiveness. Considering this, the aim is to evaluate whether a new nutraceutical supplement composition can improve and supply essential mineral nutrients, providing an improvement of obesity-related metabolic and endocrine parameters.

Methods

Sedentary volunteers (women and men) with body mass index (BMI) ≤34.9 kg/m2 were divided into two groups: Novel Nutraceutical Supplement_(S) (n = 30) and Novel Nutraceutical Supplement (n = 29), differing in the absence (S) or presence of silymarin, respectively. Volunteers were instructed to take two capsules in the morning and two capsules in the evening. No nutritional intervention was performed during the study period. The data (anthropometrics and anamneses) and harvest blood (biochemistry and hormonal exams) were collected at three different time points: baseline time [day 0 (T0)], day 90 (T90), and day 180 (T180) post-supplementation.

Results

In the anthropometric analysis, the waist circumference in middle abdomen (WC-mid) and waist circumference in iliac crest (WC-IC) were reduced. Also, the waist-to-height ratio (WHt R) and waist-to-hip ratio (WHR) seem to slightly decrease alongside the supplementation period with both nutraceutical supplements tested as well as transaminase enzyme ratio [aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio (AAR)], a known as a biomarker of NAFLD, and endocrine hormones cortisol and thyroid-stimulating hormone (TSH) at 90 and 180 days post-supplementation.

Conclusions

In a condition associated with sedentary and no nutritional intervention, the new nutraceutical supplement composition demonstrated the ability to be a strong and newfangled tool to improve important biomarkers associated with obesity and its comorbidities.

Non-Alcoholic Fatty Liver Disease (NAFLD) Pathogenesis and Natural Products for Prevention and Treatment

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease, affecting approximately one-quarter of the global population, and has become a world public health issue. NAFLD is a clinicopathological syndrome characterized by hepatic steatosis, excluding ethanol and other definite liver damage factors. Recent studies have shown that the development of NAFLD is associated with lipid accumulation, oxidative stress, endoplasmic reticulum stress, and lipotoxicity. A range of natural products have been reported as regulators of NAFLD in vivo and in vitro. This paper reviews the pathogenesis of NAFLD and some natural products that have been shown to have therapeutic effects on NAFLD. Our work shows that natural products can be a potential therapeutic option for NAFLD.

The value of combining the simple anthropometric obesity parameters, Body Mass Index (BMI) and a Body Shape Index (ABSI), to assess the risk of non-alcoholic fatty liver disease

Background

Body mass index (BMI) and A Body Shape Index (ABSI) are current independent risk factors for non-alcoholic fatty liver disease (NAFLD). The aim of this study was to explore the value of combining these two most common obesity indexes in identifying NAFLD.

Methods

The subjects in this study were 14,251 individuals from the NAfld in the Gifu Area, Longitudinal Analysis (NAGALA) cohort who underwent routine health examination. We integrated BMI with WC and with ABSI to construct 6 combined obesity indicators—obesity phenotypes, the combined anthropometric risk index (ARI) for BMI and ABSI, optimal proportional combination O_BMI+WC and O_BMI+ABSI, and multiplicative combination BMI*WC and BMI*ABSI. Several multivariable logistic regression models were established to evaluate the relationship between BMI, WC, ABSI, and the above six combined indicators and NAFLD; receiver operating characteristic (ROC) curves were drawn to compare the ability of each obesity indicator to identify NAFLD.

Results

A total of 2,507 (17.59%) subjects were diagnosed with NAFLD. BMI, WC, ABSI, and all other combined obesity indicators were significantly and positively associated with NAFLD in the current study, with BMI*WC having the strongest correlation with NAFLD in female subjects (OR per SD increase: 3.13) and BMI*ABSI having the strongest correlation in male subjects (OR per SD increase: 2.97). ROC analysis showed that ARI and O_BMI+ABSI had the best diagnostic performance in both sexes, followed by BMI*WC (area under the curve: female 0.8912; male 0.8270). After further age stratification, it was found that ARI and multiplicative indicators (BMI*WC, BMI*ABSI) and optimal proportional combination indicators (O_BMI+WC, O_BMI+ABSI) significantly improved the NAFLD risk identification ability of the basic anthropometric parameters in middle-aged females and young and middle-aged males.

Conclusion

In the general population, BMI combined with ABSI best identified obesity-related NAFLD risk and was significantly better than BMI or WC, or ABSI. We find that ARI and the multiplicative combined indicators BMI*WC and BMI*ABSI further improved risk prediction and may be proposed for possible use in clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-022-01717-8.

Abdominal obesity phenotypes are associated with the risk of developing non-alcoholic fatty liver disease: insights from the general population

Background

The diversity of obesity-related metabolic characteristics generates different obesity phenotypes and corresponding metabolic diseases. This study aims to explore the correlation of different abdominal obesity phenotypes with non-alcoholic fatty liver disease (NAFLD).

Methods

The current study included 14,251 subjects, 7411 males and 6840 females. Abdominal obesity was defined as waist circumference ≥ 85 cm in males and ≥ 80 cm in females; according to the diagnostic criteria for metabolic syndrome recommended by the National Cholesterol Education Program Adult Treatment Panel III, having more than one metabolic abnormality (except waist circumference criteria) was defined as metabolically unhealthy. All subjects were divided into 4 abdominal obesity phenotypes based on the presence ( +) or absence (− ) of metabolically healthy/unhealthy (MH) and abdominal obesity (AO) at baseline: metabolically healthy + non-abdominal obesity (MH⁻AO⁻); metabolically healthy + abdominal obesity (MH⁻AO⁺); metabolically unhealthy + non-abdominal obesity (MH⁺AO⁻); metabolically unhealthy + abdominal obesity (MH⁺AO⁺). The relationship between each phenotype and NAFLD was analyzed using multivariate logistic regression.

Results

A total of 2507 (17.59%) subjects in this study were diagnosed with NAFLD. The prevalence rates of NAFLD in female subjects with MH⁻AO⁻, MH⁻AO⁺, MH⁺AO⁻, and MH⁺AO⁺ phenotypes were 1.73%, 24.42%, 7.60%, and 59.35%, respectively. Among male subjects with MH⁻AO⁻, MH⁻AO⁺, MH⁺AO⁻, and MH⁺AO⁺ phenotypes, the prevalence rates were 9.93%, 50.54%, 25.49%, and 73.22%, respectively. After fully adjusting for confounding factors, with the MH⁻AO⁻ phenotype as the reference phenotype, male MH⁻AO⁺ and MH⁺AO⁺ phenotypes increased the risk of NAFLD by 42% and 47%, respectively (MH⁻AO⁺: OR 1.42, 95%CI 1.13,1.78; MH⁺AO⁺: OR 1.47, 95%CI 1.08,2.01); the corresponding risks of MH⁻AO⁺ and MH⁺AO⁺ in females increased by 113% and 134%, respectively (MH⁻AO⁺: OR 2.13, 95%CI 1.47,3.09; MH⁺AO⁺: OR 2.34, 95%CI 1.32,4.17); by contrast, there was no significant increase in the risk of NAFLD in the MH⁺AO⁻ phenotype in both sexes.

Conclusions

This first report on the relationship of abdominal obesity phenotypes with NAFLD showed that both MH⁻AO⁺ and MH⁺AO⁺ phenotypes were associated with a higher risk of NAFLD, especially in the female population. These data provided a new reference for the screening and prevention of NAFLD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02393-9.

Non-alcoholic fatty liver disease: a multi-system disease influenced by ageing and sex, and affected by adipose tissue and intestinal function

In recent years, a wealth of factors are associated with increased risk of developing non-alcoholic fatty liver disease (NAFLD) and NAFLD is now thought to increase the risk of multiple extra-hepatic diseases. The aim of this review is first to focus on the role of ageing and sex as key, poorly understood risk factors in the development and progression of NAFLD. Secondly, we aim to discuss the roles of white adipose tissue (WAT) and intestinal dysfunction, as producers of extra-hepatic factors known to further contribute to the pathogenesis of NAFLD. Finally, we aim to summarise the role of NAFLD as a multi-system disease affecting other organ systems beyond the liver. Both increased age and male sex increase the risk of NAFLD and this may be partly driven by alterations in the distribution and function of WAT. Similarly, changes in gut microbiota composition and intestinal function with ageing and chronic overnutrition are likely to contribute to the development of NAFLD both directly (i.e. by affecting hepatic function) and indirectly via exacerbating WAT dysfunction. Consequently, the presence of NAFLD significantly increases the risk of various extra-hepatic diseases including CVD, type 2 diabetes mellitus, chronic kidney disease and certain extra-hepatic cancers. Thus changes in WAT and intestinal function with ageing and chronic overnutrition contribute to the development of NAFLD – a multi-system disease that subsequently contributes to the development of other chronic cardiometabolic diseases.

A new perspective on NAFLD: Focusing on lipid droplets

Lipid droplets (LDs) are complex and metabolically active organelles. They are composed of a neutral lipid core surrounded by a monolayer of phospholipids and proteins. LD accumulation in hepatocytes is the distinctive characteristic of non-alcoholic fatty liver disease (NAFLD), which is a chronic, heterogeneous liver condition that can progress to liver fibrosis and hepatocellular carcinoma. Though recent research has improved our understanding of the mechanisms linking LD accumulation to NAFLD progression, numerous aspects of LD biology are either poorly understood or unknown. In this review, we provide a description of several key mechanisms that contribute to LD accumulation in hepatocytes, favouring NAFLD progression. First, we highlight the importance of LD architecture and describe how the dysregulation of LD biogenesis leads to endoplasmic reticulum stress and inflammation. This is followed by an analysis of the causal nexus that exists between LD proteome composition and LD degradation. Finally, we describe how the increase in size of LDs causes activation of hepatic stellate cells, leading to liver fibrosis and hepatocellular carcinoma. We conclude that acquiring a more sophisticated understanding of LD biology will provide crucial insights into the heterogeneity of NAFLD and assist in the development of therapeutic approaches for this liver disease.

The Symbiotic Effect of a New Nutraceutical with Yeast β-Glucan, Prebiotics, Minerals, and Silybum marianum (Silymarin) for Recovering Metabolic Homeostasis via Pgc-1α, Il-6, and Il-10 Gene Expression in a Type-2 Diabetes Obesity Model

The use of natural products and derivatives for the prevention and control of non-communicable chronic diseases, such as type-2 diabetes (T2D), obesity, and hepatic steatosis is a way to achieve homeostasis through different metabolic pathways. Thus, male C57BL/6 mice were divided into the following groups: high-fat diet (HFD) vehicle, HFD + Supplemented, HFD + Supplemented_S, and isolated compounds. The vehicle and experimental formulations were administered orally by gavage once a day over the four weeks of the diet (28 consecutive days). We evaluated the energy homeostasis, cytokines, and mitochondrial gene expression in these groups of mice. After four weeks of supplementation, only the new nutraceutical group (HFD + Supplemented) experienced reduced fasting glycemia, insulin, HOMA index, HOMA-β, dyslipidemia, ectopic fat deposition, and hepatic fibrosis levels. Additionally, the PPARγ coactivator 1 α (Pgc-1α), interleukin-6 (Il-6), and interleukin-10 (Il-10) gene expression were augmented, while hepatic steatosis decreased and liver parenchyma was recovered. The glutathione-S-transferase activity status was found to be modulated by the supplement. We discovered that the new nutraceutical was able to improve insulin resistance and hepatic steatosis mainly by regulating IL-6, IL-10, and Pgc-1α gene expression.

Effect of Flutriafol Exposure on Residue Characteristics in Pig Muscle and Fat Tissue

This study investigated the effect of exposure to flutriafol based on residues in pigs. Pigs were exposed to different concentrations (0.313, 0.625, 3.125, 6.25, and 12.5 mg/kg bw/d, n=20) for 4 wk in different treatment groups. Serum biochemical analysis, residue levels, and histological analysis were conducted using the VetTest chemistry analyzer, liquid chromatography mass spectrometry, and Masson’s trichrome staining, respectively. The body weight (initial and final) was not significantly different between groups. Parameters such as creatinine, blood urea nitrogen, alanine aminotransferase, and lipase levels were significantly different as compared to the control group. Flutriafol increased the residue limits in individual tissue of the pigs in a dose dependent manner. Flutriafol exposures indicated the presence of fibrosis, as confirmed from Masson’s trichrome staining. These results suggest that flutriafol affects the morphology and serum levels in pigs. The dietary flutriafol levels can provide a basis for maximum residue limits and food safety for pork and related products.

Association Between the Triglyceride-Glucose Index and the Incidence of Diabetes in People With Different Phenotypes of Obesity: A Retrospective Study

Aim

We aimed to examine the relationship between the Triglyceride-glucose (TyG) index and the incidence of type 2 diabetes in people with different phenotypes of obesity.

Methods

From May 1, 1994 to December 31, 2016, 15,464 participants were enrolled in the medical examination program at the Murakami Memorial Hospital to determine the relationship between the TyG index and the incidence of type 2 diabetes in people with different phenotypes of obesity after 5.38 years of follow-up.

Results

Besides triglycerides, HbA1c%, and FPG, the incidence of type 2 diabetes was found to be significantly associated with the TyG index (p <0.001), age (p <0.001), BMI (p = 0.033), current smoker (p <0.001), and fatty liver (p <0.001). In participants with visceral fat obesity and/or ectopic fat obesity and normal BMI, the TyG index was significantly associated with the incidence of type 2 diabetes after adjusting for confounding factors. In patients with BMI ≥25 mg/m2, although there was a trend of the relationship between the TyG index and the incidence of type 2 diabetes, the relationship was no longer positive.

Conclusion

In participants with obesity involving visceral fat obesity and/or fatty liver and normal BMI which is not a measure of body fat distribution, there was a significant association between the TyG index and incidence of T2DM.

The usefulness of obesity and lipid-related indices to predict the presence of Non-alcoholic fatty liver disease

Background

Conicity index, body-shape index, lipid accumulation product (LAP), waist circumference (WC), triglyceride, triglyceride-glucose (TyG) index, hepatic steatosis index (HSI), waist-to-height ratio (WHtR), TyG index-related parameters (TyG-WHtR, TyG-BMI, TyG-WC), body mass index (BMI), visceral adiposity index, triglyceride to high-density lipoprotein cholesterol ratio and body roundness index have been reported as reliable markers of non-alcoholic fatty liver disease (NAFLD). However, there is debate about which of the above obesity and lipid-related indices has the best predictive performance for NAFLD risk.

Methods

This study included 6870 female and 7411 male subjects, and 15 obesity and lipid-related indices were measured and calculated. NAFLD was diagnosed by abdominal ultrasound. The area under the curve (AUC) of 15 obesity and lipid-related indices were calculated by receiver operating characteristic (ROC) analysis.

Results

Among the 15 obesity and lipid-related indices, the TyG index-related parameters had the strongest association with NAFLD. ROC analysis showed that except for ABSI, the other 14 parameters had high predictive value in identifying NAFLD, especially in female and young subjects. Most notably, TyG index-related parameters performed better than other parameters in predicting NAFLD in most populations. In the female population, the AUC of TyG-WC for predicting NAFLD was 0.9045, TyG-BMI was 0.9084, and TyG-WHtR was 0.9071. In the male population, the AUC of TyG-WC was 0.8356, TyG-BMI was 0.8428, and TyG-WHtR was 0.8372. In addition, BMI showed good NAFLD prediction performance in most subgroups (AUC>0.8).

Conclusions

Our data suggest that TyG index-related parameters, LAP, HSI, BMI, and WC appear to be good predictors of NAFLD. Of these parameters, TyG index-related parameters showed the best predictive potential.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01561-2.

Advanced Molecular Imaging (MRI/MRS/1H NMR) for Metabolic Information in Young Adults with Health Risk Obesity

BACKGROUND

Obesity or being overweight is a medical condition of abnormal body fat accumulation which is associated with a higher risk of developing metabolic syndrome. The distinct body fat depots on specific parts of the anatomy have unique metabolic properties and different types of regional excessive fat distribution can be a disease hazard. The aim of this study was to identify the metabolome and molecular imaging phenotypes among a young adult population.

METHODS

The amount and distribution of fat and lipid metabolites profile in the abdomen, liver, and calf muscles of 46 normal weight, 17 overweight, and 13 obese participants were acquired using MRI and MR spectroscopy (MRS), respectively. The serum metabolic profile was obtained using proton NMR spectroscopy. NMR spectra were integrated into seven integration regions, which reflect relative metabolites.

RESULTS

A significant metabolic disorder symptom appeared in the overweight and obese group, and increased lipid deposition occurred in the abdomen, hepatocytes, and muscles that were statistically significant. Overall, the visceral fat depots had a marked influence on dyslipidemia biomarkers, blood triglyceride (r = 0.592, p < 0.001), and high-density lipoprotein cholesterol (r = -0.484, p < 0.001). Intrahepatocellular lipid was associated with diabetes predictors for hemoglobin (HbA1c%; r = 0.379, p < 0.001) and for fasting blood sugar (r = 0.333, p < 0.05). The lipid signals in serum triglyceride and glucose signals gave similar correspondence to biochemical lipid profiles.

CONCLUSIONS

This study proves the association between alteration in metabolome in young adults, which is the key population for early prevention of obesity and metabolic syndrome. This study suggests that dyslipidemia prevalence is influenced mainly by the visceral fat depot, and liver fat depot is a key determinant for glucose metabolism and hyperglycemia. Moreover, noninvasive advanced molecular imaging completely elucidated the impact of fat distribution on the anthropometric and laboratory parameters, especially indices of the metabolic syndrome biomarkers in young adults.

Regulation of cholesterol biosynthesis and lipid metabolism: A microRNA management perspective

Cellular disruption of lipid and cholesterol metabolism results in pathological processes linked to metabolic and cardiovascular diseases. Classically, at the transcription stages, the Cholesterol levels are controlled by two cellular pathways. First, the SREBP transcription factor family controls Cholesterol biosynthesis via transcriptional regulation of critical rate-limiting cholesterogenic and lipogenic proteins. Secondly, The LXR/RXR transcription factor family controls cholesterol shuttling via transcriptional regulation of cholesterol transport proteins. In addition, the posttranscriptional control of gene expression of various enzymes and proteins of cholesterol biosynthesis pathways is mediated by small non-coding microRNAs. Regulatory noncoding miRNAs are critical regulators of biological processes, including developmental and metabolic functions. miRNAs function to fine-tune lipid and cholesterol metabolism pathways by controlling the mRNA levels and translation of critical molecules in each pathway. This review discusses the regulatory roles of miRNAs in cholesterol and lipid metabolism via direct and indirect effects on their target genes, including SREBP, LXR, HDL, LDL, and ABCA transporters. We also discuss the therapeutic implications of miRNA functions and their purported role in the potentiation of small molecule therapies.

MicroRNA-132 may be associated with blood pressure and liver steatosis-preliminary observations in obese individuals

Recent findings in experimental models have shown that the microRNA miR-132 (mir-132) is an important regulator of liver homeostasis and lipid metabolism. We aimed to assess miR-132 expression in liver and fat tissues of obese individuals and examine its association with blood pressure (BP) and hepatic steatosis. We examined obese individuals undergoing bariatric surgery for weight loss (n = 19). Clinical and demographic information was obtained. Quantitative PCR was performed to determine tissue expression of miR-132 in liver and subcutaneous and visceral fat biopsies obtained during bariatric surgery. Liver biopsies were read by a single liver pathologist and graded for steatosis, inflammation and fibrosis. Participants (aged 39 ± 8.1 years) had a body mass index (BMI) of 42 ± 4.5 kg/m² and presented with 2.2 ± 1.2 metabolic abnormalities. Supine BP was 127 ± 16/74 ± 11 mmHg. Hepatic and visceral fat expression of miR-132 were correlated (r = 0.59, P = 0.033). There was no correlation between subcutaneous and visceral expression of miR-132 (r = -0.31, P = 0.20). Hepatic and visceral fat miR-132 expression were associated with BMI (r = 0.62 and r = 0.68, P = 0.049 respectively) and degree of liver steatosis (r = 0.60 and r = 0.55, P < 0.05, respectively). Subcutaneous fat miRNA-132 expression was correlated to office systolic BP (r = 0.46, P < 0.05), several aspects of 24 h BP (24 h systolic BP: r = 0.52; day systolic BP: r = 0.59, P < 0.05 for all), plasma triglycerides (r = 0.51, P < 0.01) and liver enzymes (ALT: r = -0.52; AST: r = -0.48, P < 0.05 for all). We found an association between miR-132 and markers of cardiovascular and metabolic disease. Reduction of miR-132 may be a target for the regulation of liver lipid homeostasis and control of obesity-related blood pressure.

MR spectroscopy of the liver - a reliable non-invasive alternative for evaluating non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is one of the most common conditions worldwide that targets the liver parenchyma. NAFLD represents an intrahepatic triglyceride accumulation in the absence of excessive alcohol consumption and other diseases that affect the liver parenchyma. The current "gold standard" for evaluating the amount of intrahepatic fat is represented by liver biopsy, but many patients are reluctant and hardly accept undergoing this procedure due to its invasive nature. The current study addresses this aspect by evaluating the reliability of liver magnetic resonance spectroscopy (MRS) in diagnosing NAFLD, compared to the traditional invasive liver biopsy. The present study included a total of 38 patients based on several well-defined inclusion and exclusion criteria. We used the same NAFLD grading system for both liver MRS and liver biopsy: grade 0: <5% hepatocytes are affected; grade I: 5-33% hepatocytes are affected; grade II: 34-66% hepatocytes are affected; grade III: >66% hepatocytes are affected. Regarding the NAFLD grade, over three-quarters of patients were classified as grade I and grade II, with a strong predilection for men. The current results indicated a significant association between the NAFLD grade indicated by liver MRS and the NAFLD grade indicated by liver biopsy. At the end of our study, we recommend using liver MRS for evaluating and grading NAFLD in association with other parameters like serum triglycerides and body mass index grade as this protocol can enhance early detection and provide an accurate grading that will lead to a proper management of this disease.

Examining the gut-liver axis in liver cancer using organoid models

The World Health Organization predicts that by 2030 liver cancer will cause 1 million deaths annually, thus becoming the third most lethal cancer worldwide. Hepatocellular carcinoma and cholangiocarcinoma are the two major primary cancer subtypes involving the liver. Both are often diagnosed late, and hence response to treatment and survival are poor. It is therefore of utmost importance to understand the mechanisms by which liver cancers initiate and progress. The causes of primary liver cancer are diverse, resulting primarily from obesity, chronic alcohol abuse or viral hepatitis. Importantly, both alcohol and high fat diet can promote intestinal permeability, enabling microbial translocation from the gut into the liver. As a result, these microbial antigens and metabolites exacerbate hepatic inflammation and fibrosis, increasing the risk of primary liver cancer. Organoids are primary, three-dimensional, stem cell derived liver models that can recapitulate many of the disease phenotypes observed in vivo. This review aims to summarize the advantages of organoid culture to examine the gut-liver axis with respect to cancer initiation and progression. In particular, the use of gut and liver organoid mono- and co-cultures together and with immune cell populations to best recapitulate disease mechanisms and develop therapeutic interventions.

Soyasaponin ameliorates obesity and reduces hepatic triacylglycerol accumulation by suppressing lipogenesis in high-fat diet-fed mice

Soyasaponins are triterpenoid glycosides found in soybean. We investigated whether soyasaponin ameliorates lipid metabolism and its possible mechanisms. In C57BL/6J mice fed a high-fat diet (HFD), soyasaponin (SAP) was orally administered for 9 weeks. Additionally, we evaluated the effect of soyasapogenols on 3T3-L1 adipocytes. In HFD-fed mice, the SAP significantly reduced body weight by 7% and relative adipose tissue weight by 35%. X-ray computed tomography demonstrated that the SAP reduced visceral and subcutaneous adipose tissue weights during week 3 of feeding. The SAP reduced sterol regulatory element-binding protein-1c (SREBP-1c) mRNA levels by 32% in the epididymal adipose tissue, significantly decreasing the triacylglycerol (TAG) content by 37% and SREBP-1c and fatty acid synthase mRNA levels by 52% and 61%, respectively, in the liver. In 3T3-L1 adipocytes, soyasapogenol B significantly decreased lipid droplets. The SAP containing soyasaponin A and B as conjugates demonstrate anti-obesity effects by suppressing adipocyte differentiation and lipogenesis, with a preventive effect on hepatic TAG accumulation by suppressing lipogenesis. PRACTICAL APPLICATION: Soyasaponin is one of the oleanane triterpenoids in soybeans. We have demonstrated that soyasaponin potently reduces body weight and white adipose tissue weight, and hepatic triacylglycerol accumulation in high-fat diet-fed mice. Thus, soyasaponin is a beneficial compound to prevent obesity and fatty liver.

Exposure to High-Fat Style Diet Induced Renal and Liver Structural Changes, Lipid Accumulation and Inflammation in Intact and Ovariectomized Female Rats

Purpose

We hypothesized that low estrogen levels aggravate obesity-related complications. Diet-induced obesity can cause distinct pathologies, including impaired glucose tolerance, inflammation, and organ injury that leads to fatty liver and chronic kidney diseases. To test this hypothesis, ovariectomized (OVX) rats were fed a high-fat style diet (HFSD), and we examined structural changes and inflammatory response in the kidney and liver.

Methods

Sprague-Dawley female rats were ovariectomized or sham-operated and divided into four groups: sham-operated rats fed a normal diet (ND); ovariectomized rats fed a normal diet (OVX-ND); sham-operated rats fed a HFSD; ovariectomized rats fed a high-fat style diet (OVX-HFSD). Mean blood pressure and fasting blood glucose were measured on weeks 0 and 10. The rats were sacrificed 10 weeks after initiation of ND or HFSD, the kidney and liver were harvested for histological, immunohistochemical and immunofluorescence studies.

Results

HFSD-fed rats presented a significantly greater adiposity index compared to their ND counterparts. Liver index, fasting blood glucose and mean blood pressure was increased in OVX-HFSD rats compared to HFSD rats at study terminal. Histological and morphometric studies showed focal interstitial mononuclear cell infiltration in the kidney of HFSD rats with mesangial expansion being greater in the OVX-HFSD rats. Both HFSD fed groups showed increased expressions of renal inflammatory markers, namely TNF-alpha, IL-6 and MCP-1, and infiltrating M1 macrophages with some influence of ovarian hormonal status. HFSD-feeding also caused hepatocellular steatosis which was aggravated in ovariectomized rats fed the same diet. Furthermore, hepatocellular ballooning was observed only in the OVX-HFSD rats. Similarly, HFSD-fed rats showed increased expressions of the inflammatory markers and M1 macrophage infiltration in the liver; however, only IL-6 expression was magnified in the OVX-HFSD.

Conclusion

Our data suggest that some of the structural changes and inflammatory response in the kidney and liver of rats fed a HFSD are exacerbated by ovariectomy.

Lactobacillus fermentum CQPC07 attenuates obesity, inflammation and dyslipidemia by modulating the antioxidant capacity and lipid metabolism in high-fat diet induced obese mice

Background

Obesity is an epidemic disease in the world, the treatment and prevention of obesity methods have gained great attention. Lactobacillus is the main member of probiotics, and the physiological activity of it is specific to different strains. This study systematically explored the anti-obesity effect and possible mechanism of Lactobacillus fermentum CQPC07 (LF-CQPC07), which was isolated from pickled vegetables.

Results

LF-CQPC07 effectively controlled the weight gain of mice caused by a high-fat diet. The results of pathological sections indicated that LF-CQPC07 alleviated hepatocyte damage and fat accumulation in adipocytes. The detection of biochemical indictors revealed that LF-CQPC07 decreased the levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), and increased the level of high-density lipoprotein cholesterol (HDL-C). Additionally, LF-CQPC07 caused the decrease in the amounts of inflammatory cytokines interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), IL-6, and interferon-γ (IFN-γ), and the increase in the amounts of the anti-inflammatory cytokines IL-10 and IL-4. LF-CQPC07 also decreased the amounts of alanine aminotransferase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP). Confirmed by qPCR, LF-CQPC07 enhanced the mRNA expression of catalase (CAT), gamma glutamylcysteine synthetase 1 (GSH1), copper/zinc superoxide dismutase (SOD1), manganese superoxide dismutase (SOD2), and glutathione peroxidase (GSH-Px). It also increased the mRNA expression levels of carnitine palmitoyltransferase 1 (CPT1), peroxisome proliferator-activated receptor alpha (PPAR-α), lipoprotein lipase (LPL), and cholesterol 7 alpha hydroxylase (CYP7A1), and decreased that of PPAR-γ and CCAAT/enhancer binding protein alpha (C/EBP-α) in the liver of mice.

Conclusion

This research confirmed that LF-CQPC07 is capable of ameliorating obesity, improving hyperlipemia, and alleviating chronic low-grade inflammation and liver injury accompanied with obesity. Its mechanism may be the regulation of antioxidant capacity and lipid metabolism. Therefore, LF-CQPC07 has enormous potential to serve as a potential probiotic for the prevention or treatment of obesity.

The Influence of Physical Activity on the Bioactive Lipids Metabolism in Obesity-Induced Muscle Insulin Resistance

High-fat diet consumption and lack of physical activity are important risk factors for metabolic disorders such as insulin resistance and cardiovascular diseases. Insulin resistance is a state of a weakened response of tissues such as skeletal muscle, adipose tissue, and liver to insulin, which causes an increase in blood glucose levels. This condition is the result of inhibition of the intracellular insulin signaling pathway. Skeletal muscle is an important insulin-sensitive tissue that accounts for about 80% of insulin-dependent glucose uptake. Although the exact mechanism by which insulin resistance is induced has not been thoroughly understood, it is known that insulin resistance is most commonly associated with obesity. Therefore, it is believed that lipids may play an important role in inducing insulin resistance. Among lipids, researchers’ attention is mainly focused on biologically active lipids: diacylglycerols (DAG) and ceramides. These lipids are able to regulate the activity of intracellular enzymes, including those involved in insulin signaling. Available data indicate that physical activity affects lipid metabolism and has a positive effect on insulin sensitivity in skeletal muscles. In this review, we have presented the current state of knowledge about the impact of physical activity on insulin resistance and metabolism of biologically active lipids.

Development and validation of screening scores of non-alcoholic fatty liver disease in middle-aged and elderly Chinese

AIM

Non-alcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease and also closely related to cardiometabolic disease. Its prevalence was estimated at over one-fourth in the general population in China. We aimed to develop effective score tools for detecting NAFLD.

METHODS

A total of 17,212 participants aged 45-70 years old were surveyed in Shanghai between 2013 and 2014, and 13,293 participants were included in this analysis. All participants were randomly classified into the exploratory group or the validation group. Candidate categorical variables were selected using a logistic regression model. The score points were generated according to the β-coefficients.

RESULTS

We developed the Shanghai Nicheng NAFLD Score I (SHNC NAFLD Score I), which included body mass index and waist circumference with an area under the receiver-operating characteristic curve (AUC) of 0.802 (95% CI 0.792-0.811) in the exploratory group and 0.802 (95% CI 0.793-0.812) in the validation group. We further developed the SHNC NAFLD Score II by adding fasting plasma glucose, triglyceride, and alanine aminotransferase/aspartate aminotransferase ratio to the SHNC NAFLD Score I, achieving an AUC of 0.852 (95% CI 0.843-0.861) in the exploratory group and 0.843 (95% CI 0.834-0.852) in the validation group. The two score tools also performed well in subjects with normal alanine aminotransferase (ALT) levels.

CONCLUSIONS

Based on anthropometric and clinical categorical variables, our two scores are effective tools for detecting NAFLD in both this southern Chinese population and their subpopulation with normal ALT levels.

Does adipose tissue inflammation drive the development of non-alcoholic fatty liver disease in obesity?

Obesity, an increasingly common problem in modern societies, is associated with acquired metabolic disturbances. In this perspective, the development of insulin resistance is now recognized to be initiated by inflammation of the adipose tissue, but the events that lead to this inflammation are still vague. Furthermore, visceral adipose tissue plays a significant role in obesity pathophysiology and in its clinical effects, such as non-alcoholic fatty liver disease (NAFLD). Among the possible mechanisms linking NAFLD and obesity, we focused on Visfatin/NAMPT, mostly produced by macrophages infiltrated in adipose tissue and a biomarker of the inflammatory cascade affecting hepatic inflammation in NAFLD. We also addressed the signalling pathway triggered by the binding of VEGF-B to its receptor, which mediates lipid fluxes throughout the body, being a promising target to prevent ectopic lipid accumulation. We reviewed the available literature on the topic and we suggest a crosstalk between adipose tissue inflammation and NAFLD in order to provide new insights about the putative mechanisms involved in the development of NAFLD in the obesity context. A better understanding of the pathophysiological processes underlying NAFLD will allow the development of new therapeutic approaches.

Effect of alcohol consumption and the presence of fatty liver on the risk for incident type 2 diabetes: a population-based longitudinal study

INTRODUCTION

Both fatty liver disease (FLD) and alcohol consumption have been reported to affect incident type 2 diabetes mellitus. The aim of this study was to evaluate the combined effect of FLD and alcohol consumption on incident type 2 diabetes.

RESEARCH DESIGN AND METHODS

In this historical cohort study involving 9948 men, we investigated the influence of the presence of FLD and the grades of alcohol consumption on incident type 2 diabetes using Cox proportional hazards models. We categorized the participants into the following four groups: none or minimal alcohol consumption, <40 g/week; light, 40-140 g/week; moderate, 140-280 g/week; or heavy alcohol consumption, >280 g/week. FLD was diagnosed by abdominal ultrasonography.

RESULTS

During the median 6.0-year follow-up, 568 participants developed type 2 diabetes. Heavy alcohol consumers with FLD showed a higher risk for developing type 2 diabetes compared with the other groups. Moderate alcohol consumers without FLD had a significantly higher risk for developing incident type 2 diabetes, compared with none or minimal and light alcohol consumers without FLD. In contrast, there was no apparent difference in the risk for incident type 2 diabetes between none or minimal, light, and moderate alcohol consumers with FLD. Furthermore, there was no statistically significant difference in the risk for incident type 2 diabetes between a moderate and heavy alcohol consumer without FLD and a none or minimal, light, and moderate alcohol consumer with FLD.

CONCLUSIONS

To prevent incident type 2 diabetes, we should acknowledge that the impact of alcohol consumption may vary in the presence of FLD.

Metformin Attenuates Liver Fat Content: Finding from Schizophrenia Patients with Olanzapine-induced Weight Gain

Objective

This study was performed to evaluate the efficacy of metformin on liver fat content (LFC) in first episode schizophrenia patients with olanzapine-induced weight gain, and the relationship between the change of LFC and the other metabolic indices.

Methods

In a double-blind study, the clinically stable inpatients with first-episode schizophrenia under olanzapine monotherapy who gained more than 7% of their baseline weight were randomly assigned to two groups; one with olanzapine plus metformin (1,000 mg/day) (metformin group) and the other with olanzapine plus placebo (placebo group) for 16 weeks. All patients continued to maintain the original olanzapine dosage. LFC was measured by magnetic resonance imaging at baseline and at the end of 16 weeks, respectively. At the same time, glucose and lipid metabolism, homeostasis model assessment of insulin resistance index (HOMA-IR) were measured respectively, analyzing the correlation between the change value of LFC and other indicators.

Results

Over the 16-week study period, LFC value in metformin group decreased compared with baseline. LFC change across the 16-week treatment period was −2.91% for the metformin group and 0.59% for the placebo group, with a between-group difference of −3.5% (95% confidence interval, −6.08 to −0.93; p = 0.009). Compared to baseline, in the metformin group, triglyceride and HOMA-IR reduced significantly, while high density lipoprotein cholesterol increased significantly at weeks 16. There was positive correlation between LFC changes and triglycerides, HOMA-IR changes significantly.

Conclusion

Metformin can significantly attenuate LFC in schizophrenia patients with olanzapine-induced weight gain. It may be related to the improvement of the part of the glucolipid metabolic indices.

Associations between adipose tissue volume and small molecules in plasma and urine among asymptomatic subjects from the general population

Obesity is one of the major risk factor for cardiovascular and metabolic diseases. A disproportional accumulation of fat at visceral (VAT) compared to subcutaneous sites (SAT) has been suspected as a key detrimental event. We used non-targeted metabolomics profiling to reveal metabolic pathways associated with higher VAT or SAT amount among subjects free of metabolic diseases to identify possible contributing metabolic pathways. The study population comprised 491 subjects [mean (standard deviation): age 44.6 yrs (13.0), body mass index 25.4 kg/m² (3.6), 60.1% females] without diabetes, hypertension, dyslipidemia, the metabolic syndrome or impaired renal function. We associated MRI-derived fat amounts with mass spectrometry-derived metabolites in plasma and urine using linear regression models adjusting for major confounders. We tested for sex-specific effects using interactions terms and performed sensitivity analyses for the influence of insulin resistance on the results. VAT and SAT were significantly associated with 155 (101 urine) and 49 (29 urine) metabolites, respectively, of which 45 (27 urine) were common to both. Major metabolic pathways were branched-chain amino acid metabolism (partially independent of insulin resistance), surrogate markers of oxidative stress and gut microbial diversity, and cortisol metabolism. We observed a novel positive association between VAT and plasma levels of the potential pharmacological agent piperine. Sex-specific effects were only a few, e.g. the female-specific association between VAT and O-methylascorbate. In brief, higher VAT was associated with an unfavorable metabolite profile in a sample of healthy, mostly non-obese individuals from the general population and only few sex-specific associations became apparent.

The FATZO mouse, a next generation model of type 2 diabetes, develops NAFLD and NASH when fed a Western diet supplemented with fructose

BACKGROUND

Metabolic disorders such as insulin resistance, obesity, and hyperglycemia are prominent risk factors for the development of non-alcoholic fatty liver disease (NAFLD)/steatohepatitis (NASH). Dietary rodent models employ high fat, high cholesterol, high fructose, methionine/choline deficient diets or combinations of these to induce NAFLD/NASH. The FATZO mice spontaneously develop the above metabolic disorders and type 2 diabetes (T2D) when fed with a normal chow diet. The aim of the present study was to determine if FATZO mice fed a high fat and fructose diet would exacerbate the progression of NAFLD/NASH.

METHODS

Male FATZO mice at the age of 8 weeks were fed with high fat Western diet (D12079B) supplemented with 5% fructose in the drinking water (WDF) for the duration of 20 weeks. The body weight, whole body fat content, serum lipid profiles and liver function markers were examined monthly along with the assessment of liver histology for the development of NASH. In addition, the effects of obeticholic acid (OCA, 30 mg/kg, QD) on improvement of NASH progression in the model were evaluated.

RESULTS

Compared to normal control diet (CD), FATZO mice fed with WDF were heavier with higher body fat measured by qNMR, hypercholesterolemia and had progressive elevations in AST (~ 6 fold), ALT (~ 6 fold), liver over body weight (~ 2 fold) and liver triglyceride (TG) content (1.4-2.9 fold). Histological examination displayed evidence of NAFLD/NASH, including hepatic steatosis, lobular inflammation, ballooning and fibrosis in FATZO mice fed WDF. Treatment with OCA for 15 weeks in FATZO mice on WDF significantly alleviated hypercholesterolemia and elevation of AST/ALT, reduced liver weight and liver TG contents, attenuated hepatic ballooning, but did not affect body weight and blood TG levels.

CONCLUSION

WDF fed FATZO mice represent a new model for the study of progressive NAFLD/NASH with concurrent metabolic dysregulation.

Female Dietary Patterns and the Pathogenesis of NAFLD

In Europe as well as the United States, nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and is strongly associated with obesity and type 2 diabetes mellitus (T2DM). Nonalcoholic fatty liver disease is defined as a hepatic manifestation of the metabolic syndrome. Being a very powerful and independent cardiovascular risk factor, NAFLD increases cardiovascular and overall mortality to a significant degree. The purpose of this review was to determine sex- and gender-specific differences in the prevalence and pathogenesis of NAFLD and delineate the specific characteristics of NAFLD as a systemic disease in men and women. Postmenopausal women and women with endocrine disorders such as the polycystic ovarian syndrome are at high risk of developing NAFLD. The increasing incidence of female NAFLD after menopause appears to be related to reduced estrogen and increased testosterone levels, as well as changes in the distribution of fatty tissue. Finally, the role of gender-specific nutrition patterns in the pathogenesis of NAFLD will be discussed. Fructose consumption from industrialized products is a promoter of NAFLD, depending on the total daily calorie intake of macronutrients. A higher level of health literacy and conscious food behavior have been noted among women of all age groups compared to males, which could play a role in the pathogenesis of NAFLD. Health professionals are confronted with the challenges of early diagnosis by the use of sensitive, reliable, and noninvasive diagnostic tools, including screening algorithms for high-risk persons and providing gender-specific nutritional support as a crucial element of treatment and disease prevention.

Obesity and incidence of diabetes: Effect of absence of metabolic syndrome, insulin resistance, inflammation and fatty liver

BACKGROUND AND AIMS

Obesity is frequently associated with non-alcoholic fatty liver disease (NAFLD), insulin resistance (IR), inflammation and metabolic syndrome (MetS), all of which increase the risk of type 2 diabetes (T2DM). However, the role of these risk factors in mediating the effect of obesity remains unclear. We investigated the association between obesity and T2DM in the absence and presence of NAFLD, IR, inflammation and MetS components.

METHODS

29,836 obese subjects without diabetes were studied in a Korean health screening program. Obesity was defined by the appropriate ethnic-specific body mass index (BMI) threshold ≥25 kg/m². Hazard ratios (HRs and 95% confidence intervals, CIs) for incident T2DM were estimated for the group with no hypertension, dyslipidemia, impaired fasting glucose, fatty liver, IR, or inflammation (n = 1717), compared to the reference group, with one or more of these factors (n = 19,757).

RESULTS

Mean (SD) age at baseline was 37 (7) years and 1200 incident cases of diabetes occurred. Crude T2D incidence was 12.6/10,000 person-years in the group without metabolic abnormality and 143/10,000 person-years in the reference group. HR (95% CIs) for incident diabetes was 0.13 (0.06, 0.33) in the group without metabolic abnormality.

CONCLUSIONS

Obese subjects without components of the metabolic syndrome, IR, fatty liver and inflammation have an approximately 11-fold lower risk of incident type 2 diabetes than obese subjects who have these risk factors. These simple factors could be used to target limited resources in high risk obese subjects in the prevention of diabetes.

Ectopic fat obesity presents the greatest risk for incident type 2 diabetes: a population-based longitudinal study

OBJECTIVES

Obesity is a risk factor for type 2 diabetes mellitus. Among obesity, visceral fat obesity, and ectopic fat obesity, it has been unclear which has the greatest effect on incident diabetes.

METHODS

In this historical cohort study of 8430 men and 7034 women, we investigated the effect of obesity phenotypes on incident diabetes. Obesity, visceral fat obesity, and ectopic fat obesity were defined as body mass index ≥25 kg/m², waist circumference ≥90 cm in men or ≥80 cm in women, and having fatty liver diagnosed by abdominal ultrasonography, respectively. We divided the participants into eight groups according to the presence or absence of the three obesity phenotypes.

RESULTS

During the median 5.8 years follow-up for men and 5.1 years follow-up for women, 286 men and 87 women developed diabetes. Compared to the non-obese group, the hazard ratios (HRs) of incident diabetes in the only-obesity, only-visceral fat obesity, only-ectopic fat obesity groups, and with all-three types of obesity group were 1.85 (95%CI 1.06-3.26, p = 0.05) in men and 1.79 (0.24-13.21, p = 0.60) in women, 3.41 (2.51-4.64, p < 0.001) in men and 2.30 (0.87-6.05, p = 0.12) in women, 4.74 (1.91-11.70, p < 0.001) in men and 13.99 (7.23-27.09, p < 0.001) in women and 10.5 (8.02-13.8, p < 0.001) in men and 30.0 (18.0-50.0, p < 0.001) in women. Moreover, the risk of incident diabetes of the groups with ectopic fat obesity were almost higher than that of the four groups without ectopic fat obesity.

CONCLUSION

Ectopic fat obesity presented the greatest risk of incident type 2 diabetes.

Resolution of fatty liver and weight loss: Independent associations with changes in serum lipids and apolipoproteins

BACKGROUND AND AIMS

It is uncertain whether resolution of fatty liver can improve cardiovascular disease risk factors, independently of changes in body mass index (BMI). Our aim was to test whether resolution of fatty liver is associated with improvements in components of the lipid profile, independently of changes in BMI, and to quantify and compare the magnitude of benefit of resolution of liver fat, and decreases in BMI on the lipid profile.

METHODS

36,195 subjects with fatty liver were studied. Persistence/resolution of fatty liver was determined by ultrasound at follow up (mean = 4.93 years). Total cholesterol, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and apolipoproteins were measured at baseline and follow up. Regression modelling was undertaken to test the independence of associations between change in fatty liver status or change in BMI, with any change in lipid profile concentrations between baseline and follow up.

RESULTS

Mean (SD) age was 36.3 ± 6.6 and 39.8 ± 8.7 years (men and women, respectively). Resolution of fatty liver occurred in 7,086, and persisted in 29,109 subjects. Mean ± SD weight change was -3.2 ± 4.3 (∼1 kg/m² decrease in BMI) with resolution of, and +0.5 ± 3.5 kg with persistence of fatty liver, respectively. Both resolution of fatty liver and decrease in BMI were independently associated with improvements in all components of the lipid profile and there was a similar magnitude of benefit associated with resolution of fatty liver, or 1 kg/m² decrease in BMI.

CONCLUSIONS

Resolution of fatty liver improves the lipid profile, independently of weight loss.

Steatosis in South African women: How much and why?

Background

Globally, steatosis is the commonest type of liver pathology and is closely associated with obesity and the metabolic syndrome. Obesity is common in urban African females but no data is available on hepatic fat content in this population group when compared to other ethnic groups. The aim of this study was therefore to compare hepatic fat content in woman from different ethnic groups in South Africa and to characterise the principle determinants of liver fat.

Materials and methods

A convenience sample of 106 (48 Indian, 29 African and 29 Caucasian) female volunteers aged 20–60 years and having no history of cardiometabolic disorders were recruited. Hepatic fat was determined from CT scans using the liver-spleen attenuation ratio (LAR), which decreases with increasing levels of hepatic fat. Anthropometric and cardiometabolic parameters were measured with insulin resistance determined using the HOMA index and dysglycaemia defined as fasting glucose ≥5.60 mmol/L.

Results

The African subjects had significantly lower hepatic fat content (LAR as median [interquartile range]: 1.35 [1.28, 1.41]) than the Indian (1.22 [1.10, 1.35]; p<0.005) and Caucasian (1.27 [1.16, 1.33]; p<0.05) females even though they had significantly higher BMIs than both groups (p<0.0005 and p<0.05, respectively). Linear regression showed that: subcutaneous abdominal fat was a significant (unstandardised β = 0.007; p = 0.03) negative, whilst insulin resistance (β = -0.97; p = 0.01) and dysglycaemia (β = -3.58; p = 0.01) were significant positive determinants of liver fat; higher hepatic fat levels in subjects with the metabolic syndrome were explained by insulin resistance and dysglycaemia.

Discussion

African ethnicity is associated with low liver fat content. Subcutaneous abdominal fat protects against steatosis, possibly by acting as a triglyceride reservoir. Insulin resistance and dysglycaemia lead to greater hepatic fat deposition and explain higher liver fat levels in subjects with the metabolic syndrome. These observations must be further investigated in longitudinal surveys.

Metabolically healthy obesity without fatty liver and risk of incident type 2 diabetes: A meta-analysis of prospective cohort studies

OBJECTIVE

A meta-analysis indicated that metabolically healthy obesity (MHO) presents a risk of incident type 2 diabetes, but it has not yet been established whether MHO without fatty liver (w/o FL) also presents a risk of incident diabetes.

METHODS

plus the presence of non or one of the following factors: hypertension, impaired fasting glucose, low high-density lipoprotein cholesterol, and hypertriglyceridemia. Using a random effects model, we calculated the pooled relative risks (RRs) and 95% confidence intervals (CIs) of incident diabetes.

RESULTS

Our meta-analysis included three studies from the databases plus the NAGALA study, with a total of 134,667 subjects, including 8675 MHO subjects w/o FL and 7218 MHO subjects with fatty liver (wFL). Compared to the metabolically healthy non-overweight subjects w/o FL, the RRs of incident diabetes in the MHO w/o FL and MHO wFL groups were 1.42 (95%CI 1.11-1.77) and 3.28 (95%CI 2.30-4.67).

CONCLUSIONS

Our meta-analysis results demonstrate that the MHO phenotype, with or without fatty liver, presents a risk of the development of type 2 diabetes. Individuals with MHO who do not have fatty liver should be monitored carefully - similarly to those with fatty liver - for the development of diabetes.

Neonatal overfeeding in mice aggravates the development of methionine and choline-deficient diet-induced steatohepatitis in adulthood

Overfeeding in early life is associated with obesity and insulin resistance in adulthood. In the present study, a well-characterized mouse model was used to investigate whether neonatal overfeeding increases susceptibility to the development of non-alcoholic steatohepatitis (NASH) following feeding with a methionine and choline- deficient (MCD) diet. Neonatal overfeeding was induced by adjusting litters to 3 pups per dam (small litter size, SL) in contrast to 10 pups per dam as control (normal litter size, NL). At 11 weeks of age, mice were fed with standard (S) or a methionine and choline-deficient (MCD) diet for 4 weeks. Glucose tolerance tests, tissue staining with haematoxylin and eosin, oil-red O and immunohistochemistry for F4/80, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were performed. Compared with NL mice, SL mice exhibited higher body weight gain from 2 weeks of age throughout adulthood, and more profound glucose intolerance as adults. Sterol regulatory element-binding protein 1c and fatty acid synthase mRNA expression levels in liver were upregulated in SL mice at 3 weeks of age. MCD diet induced typical NASH, especially in SL-MCD mice, evidenced by marked fat accumulation, macrovescular steatosis, ballooned hepatocytes, inflammatory cells infiltration and tumour necrosis factor-α mRNA upregulation in the liver, as well as increased alanine aminotransferase and aspartate aminotransferase levels in the serum. There were no significant differences in liver fibrosis in all groups. Overfeeding during early life exhibited effect with administration of MCD diet in inducing adverse effects on the metabolic function and in promoting the progression of NASH in mice, possibly mediated through dysregulated lipid metabolism in hepatocytes and aggravated hepatic inflammation.

Nonalcoholic fatty liver disease: cause or consequence of insulin resistance?

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) are pathological conditions that are co-occurring, and have been reaching epidemic proportions. One of the most significant risk factors for the development of both T2DM and NAFLD is obesity, which increases existing insulin resistance (IR). IR thought to be one of the main pathogenic causes linking T2DM and NAFLD. In recent years, there has been increased interest in obtaining non-invasive methods for assessing fibrosis and determining indications for liver biopsy, such as the NAFLD fibrosis score, extended liver fibrosis panel, and transient elastography. However, liver biopsy remains the gold standard for diagnosing NAFLD. Given that patients with T2DM are at higher risk of NAFLD than the general population, and that the presence of diabetes is a risk factor for the progression of NAFLD, patients with T2DM should be more closely monitored by clinicians. The present review paper is devoted to the search for causeeffect relationships of concurrent diseases such as NAFLD and disorders of carbohydrate metabolism, and priority areas of diagnosis of NAFLD.

Influence of dietary macronutrients on liver fat accumulation and metabolism

The liver is a principal metabolic organ within the human body and has a major role in regulating carbohydrate, fat, and protein metabolism. With increasing rates of obesity, the prevalence of non-alcoholic fatty liver disease (NAFLD) is growing. It remains unclear why NAFLD, which is now defined as the hepatic manifestation of the metabolic syndrome, develops but lifestyle factors such as diet (ie, total calorie and specific nutrient intakes), appear to play a key role. Here we review the available observational and intervention studies that have investigated the influence of dietary macronutrients on liver fat content. Findings from observational studies are conflicting with some reporting that relative to healthy controls, patients with NAFLD consume diets higher in total fat/saturated fatty acids, whilst others find they consume diets higher in carbohydrates/sugars. From the limited number of intervention studies that have been undertaken, a consistent finding is a hypercaloric diet, regardless of whether the excess calories have been provided either as fat, sugar, or both, increases liver fat content. In contrast, a hypocaloric diet decreases liver fat content. Findings from both hyper- and hypo-caloric feeding studies provide some suggestion that macronutrient composition may also play a role in regulating liver fat content and this is supported by data from isocaloric feeding studies; fatty acid composition and/or carbohydrate content/type appear to influence whether there is accrual of liver fat or not. The mechanisms by which specific macronutrients, when consumed as part of an isocaloric diet, cause a change in liver fat remain to be fully elucidated.

Combined effect of body mass index and waist-height ratio on incident diabetes; a population based cohort study

We investigated the impact of combined effect of body mass index and waist-to-height ratio on risk of diabetes. Overweight and abdominal obesity were defined as body mass index ≥23 kg/m² and waist-to-height ratio ≥0.5, respectively. We divided participants into four groups according to presence of overweight and/or abdominal obesity. About 20% individuals with overweight did not complicated with an abdominal obesity. Among 3,737 participants, 286 participants had diabetes at baseline-examination. Adjusted odds ratios for prevalence of diabetes compared with non-overweight participants without abdominal obesity were as follow: 1.87 (95% confidence interval 1.09-3.14, p = 0.024) in non-overweight participants with abdominal obesity, 1.51 (0.87-2.55, p = 0.141) in overweight participants without abdominal obesity and 3.25 (2.37-4.52, p<0.001) in overweight participants with abdominal obesity. In the follow-up examination, 86 participants were diagnosed as diabetes among 2,263 participants. Adjusted odds ratios for incident diabetes were as follow: 2.59 (0.98-6.44, p = 0.056) in non-overweight participants with abdominal obesity, 1.65 (0.64-4.00, p = 0.288) in overweight participants without abdominal obesity and 2.77 (1.55-5.15, p<0.001) in overweight participants with abdominal obesity. Non-overweight individuals with abdominal obesity as well as overweight individuals with abdominal obesity was associated with diabetes compared with non-overweight individuals without abdominal obesity.

Molecular mechanisms underlying metabolic syndrome: the expanding role of the adipocyte

The metabolic syndrome (MetS) is defined as a cluster of 3 or more metabolic and cardiovascular risk factors and represents a serious problem for public health. Altered function of adipose tissue has a significant impact on whole-body metabolism and represents a key driver for the development of these metabolic derangements, collectively referred as to MetS. In particular, increased visceral and ectopic fat deposition play a major role in the development of insulin resistance and MetS. A large body of evidence demonstrates that aging and MetS share several metabolic alterations. Of importance, molecular pathways that regulate lifespan affect key processes of adipose tissue physiology, and transgenic mouse models with adipose-specific alterations in these pathways show derangements of adipose tissue and other metabolic features of MetS, which highlights a causal link between dysfunctional adipose tissue and deleterious effects on whole-body homeostasis. This review analyzes adipose tissue-specific dysfunctions, including metabolic alterations that are related to aging, that have a significant impact on the development of MetS.-Armani, A., Berry, A., Cirulli, F., Caprio, M. Molecular mechanisms underlying metabolic syndrome: the expanding role of the adipocyte.

The Role of Lipid and Lipoprotein Metabolism in Non-Alcoholic Fatty Liver Disease

Due to the epidemic of obesity across the world, nonalcoholic fatty liver disease (NAFLD) has become one of the most prevalent chronic liver disorders in children and adolescents. NAFLD comprises a spectrum of fat-associated liver conditions that can result in end-stage liver disease and the need for liver transplantation. Simple steatosis, or fatty liver, occurs early in NAFLD and may progress to nonalcoholic steatohepatitis, fibrosis and cirrhosis with increased risk of hepatocellular carcinoma. The mechanism of the liver injury in NAFLD is currently thought to be a “multiple-hit process” where the first “hit” is an increase in liver fat, followed by multiple additional factors that trigger the inflammatory activity. At the onset of disease, NAFLD is characterized by hepatic triglyceride accumulation and insulin resistance. Liver fat accumulation is associated with increased lipotoxicity from high levels of free fatty acids, free cholesterol and other lipid metabolites. As a consequence, mitochondrial dysfunction with oxidative stress and production of reactive oxygen species and endoplasmic reticulum stress-associated mechanisms, are activated. The present review focuses on the relationship between intra-cellular lipid accumulation and insulin resistance, as well as on lipid and lipoprotein metabolism in NAFLD.

Nonoverweight nonalcoholic fatty liver disease and incident cardiovascular disease: A post hoc analysis of a cohort study

Nonalcoholic fatty liver disease (NAFLD) is known as a risk of incident cardiovascular disease (CVD). About 20% of NAFLD occurs in nonobese individuals. However, it remains to be elucidated the association between nonoverweight with NAFLD and a risk of incident CVD. Therefore, we investigated the risk of nonoverweight with NAFLD for incident CVD.We performed a post-hoc analysis of the previous prospective cohort study, in which 1647 Japanese were enrolled. Abdominal ultrasonography was used to diagnose NAFLD. Overweight was defined as body mass index ≥23 kg/m, which is recommended by World Health Organization for Asian. We divided participants into 4 phenotypes by existence of NAFLD and/or overweight. The hazard risks of the 4 phenotypes for incident CVD were calculated by Cox hazard model after adjusting for age, sex, smoking status, exercise, hypertension, hyperglycemia, hypertriglyceridemia, and low high-density lipoprotein cholesterol at baseline examination.Incident proportions of CVD were 0.6% in nonoverweight without NAFLD, 8.8% in nonoverweight with NAFLD, 1.8% in overweight without NAFLD, and 3.3% in overweight with NAFLD. Compared with nonoverweight without NAFLD, the adjusted hazard ratios of incident CVD were 10.4 (95% confidence interval 2.61-44.0, P = .001) in nonoverweight with NAFLD, 1.96 (0.54-7.88, P = .31) in overweight without NAFLD, and 3.14 (0.84-13.2, P = .09) in overweight with NAFLD.Nonoverweight with NAFLD was associated with higher risk of incident CVD. We should pay attention to NAFLD, even in nonoverweight individuals, to prevent further CVD events.

Non-alcoholic fatty liver disease: an emerging driving force in chronic kidney disease

Non-alcoholic fatty liver disease (NAFLD) is caused by an accumulation of fat in the liver; the condition can progress over time to increase the risk of developing cirrhosis, end-stage liver disease and hepatocellular carcinoma. The prevalence of NAFLD is increasing rapidly owing to the global epidemics of obesity and type 2 diabetes mellitus (T2DM), and NAFLD has been predicted to become the most important indication for liver transplantation over the next decade. It is now increasingly clear that NAFLD not only affects the liver but can also increase the risk of developing extra-hepatic diseases, including T2DM, cardiovascular disease and chronic kidney disease (CKD), which have a considerable impact on health-care resources. Accumulating evidence indicates that NAFLD exacerbates insulin resistance, predisposes to atherogenic dyslipidaemia and releases a variety of proinflammatory factors, prothrombotic factors and profibrogenic molecules that can promote vascular and renal damage. Furthermore, communication or 'crosstalk' between affected organs or tissues in these diseases has the potential to further harm function and worsen patient outcomes, and increasing amounts of evidence point to a strong association between NAFLD and CKD. Whether a causal relationship between NAFLD and CKD exists remains to be definitively established.