Lean-non-alcoholic fatty liver disease increases risk for metabolic disorders in a normal weight Chinese population

Fatty liver diseases, mechanisms, and potential therapeutic plant medicines

The liver is an important metabolic organ and controls lipid, glucose and energy metabolism. Dysruption of hepatic lipid metabolism is often associated with fatty liver diseases, including nonalcoholic fatty liver disease (NAFLD), alcoholic fatty liver diseases (AFLD) and hyperlipidemia. Recent studies have uncovered the contribution of hormones, transcription factors, and inflammatory cytokines to the pathogenesis of dyslipidemia and fatty liver diseases. Moreover, a significant amount of effort has been put to examine the mechanisms underlying the potential therapeutic effects of many natural plant products on fatty liver diseases and metabolic diseases. We review the current understanding of insulin, thyroid hormone and inflammatory cytokines in regulating hepatic lipid metabolism, focusing on several essential transcription regulators, such as Sirtuins (SIRTs), Forkhead box O (FoxO), Sterol-regulatory element-binding proteins (SREBPs). We also discuss a few representative natural products with promising thereapeutic effects on fatty liver disease and dyslipidemia.

The Prevalence of Lean/Nonobese Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

BACKGROUND AND AIM

The prevalence of lean/nonobese nonalcoholic fatty liver disease (NAFLD) ranges widely in studies. Thus, here, we aimed to perform a meta-analysis on NAFLD prevalence in the lean or nonobese population to give clarity.

MATERIALS AND METHODS

PubMed, Embase, and the Cochrane Library databases were systematically searched to identify studies reporting NAFLD prevalence in the lean/nonobese population. Lean or nonobese was defined by body mass index cutoffs reported by authors in original studies. NAFLD prevalence based on community, population, or health checkups was combined with random-effect model after logit transformation. Subgroup analysis and meta-regression were further performed to investigate the heterogenicity.

RESULTS

A total of 45 studies were enrolled in the final analysis, with 55,936 lean/nonobese subjects included, among whom 7351 NAFLD patients were diagnosed. Overall, the pooled NAFLD prevalence of the lean or nonobese population was 10.2% (95% confidence interval: 7.6%-13.6%) and 15.7% (95% confidence interval: 12.5%-19.6%), respectively. Compared with western studies, the NAFLD prevalence in the lean or nonobese population was lower in eastern studies. In addition, the NAFLD prevalence in both the lean and nonobese population showed a general upward trend during recent years. The prevalence was similar in community-based and health checkup-based studies. Lean/nonobese NAFLD patients had significantly lower rates of hypertension, lower uric acid and fasting plasma glucose, and a higher level of high-density lipoprotein than nonlean/obese patients.

CONCLUSIONS

The prevalence of NAFLD in the lean/nonobese population is not rare in either the western or eastern regions of the world. This meta-analysis of prevalence assessment and clinical characteristics should enable higher confidence in more specific interventions and health care standards for these patients.

Implications of abnormal liver function in pregnancy and non-alcoholic fatty liver disease

Elevated liver enzyme levels can sometimes be encountered in asymptomatic pregnant women. Similar to non-pregnant subjects, women with elevated gamma glutamyltransferase or alanine aminotransferase in early pregnancy have increased risk of subsequent complications, especially gestational diabetes mellitus. In non-pregnant subjects, the commonest cause of abnormal liver function currently is non-alcoholic fatty liver disease. Risk factors include obesity, diabetes, and the metabolic syndrome. It can progress to hepatocellular carcinoma through the development of steatohepatitis, and has become the leading cause for liver transplantation in women. Found in as many as 16-18% of pregnant women, it is associated with an increased risk of pregnancy complications and abnormal foetal growth, which predisposes the offspring to the same problem subsequently. This condition probably explains the majority of the cases of "idiopathic" abnormal liver function in pregnancy, and should be looked out for in high-risk women owing to its implications on their long-term health outcome.

Visceral-to-Subcutaneous Abdominal Fat Ratio Is Associated with Nonalcoholic Fatty Liver Disease and Liver Fibrosis

BACKGROUND

We evaluated the association of visceral-to-subcutaneous fat ratio (VSR) with nonalcoholic fatty liver disease (NAFLD) and advanced fibrosis degree based on noninvasive serum fibrosis markers in the general population with NAFLD.

METHODS

This is a cross-sectional study, in 7,465 Korean adults who underwent health screening examinations. NAFLD was defined as fatty liver detected on ultrasonography, and visceral and subcutaneous abdominal fat was measured using computed tomography. We predicted fibrosis based on the fibrosis-4 (FIB-4) score and aspartate aminotransferase-to-platelet ratio index (APRI) and categorized the risk for advanced fibrosis as low, indeterminate, or high.

RESULTS

The multivariable-adjusted prevalence ratios for indeterminate to high risk of advanced fibrosis based on FIB-4, determined by comparing the second, third, and fourth quartiles with the first quartile of VSR, were 3.38 (95% confidence interval [CI], 0.64 to 17.97), 9.41 (95% CI, 1.97 to 45.01), and 19.34 (95% CI, 4.06 to 92.18), respectively. The multivariable-adjusted prevalence ratios for intermediate to high degree of fibrosis according to APRI also increased across VSR quartiles (5.04 [95% CI, 2.65 to 9.59], 7.51 [95% CI, 3.91 to 14.42], and 19.55 [95% CI, 9.97 to 38.34], respectively). High VSR was more strongly associated with the prevalence of NAFLD in nonobese subjects than in obese subjects, and the associations between VSR and intermediate to high probability of advanced fibrosis in NAFLD were stronger in obese subjects than in nonobese subjects.

CONCLUSION

High VSR values predicted increased NAFLD risk and advanced fibrosis risk with NAFLD, and the predictive value of VSR for indeterminate to high risk of advanced fibrosis was higher in obese subjects than in nonobese subjects.

Nonalcoholic Fatty Liver Disease Pandemic Fuels the Upsurge in Cardiovascular Diseases

Cardiovascular diseases (CVDs) remain a leading cause of death worldwide. Among the major risk factors for CVD, obesity and diabetes mellitus have received considerable attention in terms of public policy and awareness. However, the emerging prevalence of nonalcoholic fatty liver disease (NAFLD), as the most common liver and metabolic disease and a cause of CVD, has been largely overlooked. Currently, the number of individuals with NAFLD is greater than the total number of individuals with diabetes mellitus and obesity. Epidemiological studies have established a strong correlation between NAFLD and an increased risk of CVD and CVD-associated events. Although debate continues over the causal relationship between NAFLD and CVD, many mechanistic and longitudinal studies have indicated that NAFLD is one of the major driving forces for CVD and should be recognized as an independent risk factor for CVD apart from other metabolic disorders. In this review, we summarize the clinical evidence that supports NAFLD as a risk factor for CVD epidemics and discuss major mechanistic insights regarding the acceleration of CVD in the setting of NAFLD. Finally, we address the potential treatments for NAFLD and their potential impact on CVD.

Nonalcoholic Fatty Liver Disease: An Emerging Driver of Hypertension

Hypertension, a multifactorial disorder resulting from the interplay between genetic predisposition and environmental risk factors, affects ≈30% of adults. Emerging evidence has shown that nonalcoholic fatty liver disease (NAFLD), as an underestimated metabolic abnormality, is strongly associated with an increased risk of incident prehypertension and hypertension. However, the role of NAFLD in the development of hypertension is still obscure and is highly overlooked by the general public. Herein, we highlight the epidemiological evidence and putative mechanisms focusing on the emerging roles of NAFLD in hypertension, with the purpose of reinforcing the notion that NAFLD may serve as an independent risk factor and an important driving force in the development and progression of hypertension. Finally, we also briefly summarize the current potential treatments for NAFLD that might also be beneficial approaches against hypertension.

Homeostatic model assessment of insulin resistance closely related to lobular inflammation in nonalcoholic fatty liver disease

OBJECTIVE

Insulin resistance (IR) has been established as a major risk factor for nonalcoholic fatty liver disease (NAFLD) where it exerts effects on plasma glucose homeostasis, cellular anabolism, and organ glucose uptake. Owing to paucity of studies focused on peripheral IR in relation to pathological outcome, we aim to investigate homeostatic model assessment of insulin resistance (HOMA-IR) by histological characteristics of NAFLD.

METHODS

Liver biopsy of 588 patients was screened. After excluding etiologies other than NAFLD and factors contributing to IR, serum HOMA-IR was compared with patients' histologic features. Univariate and multivariate analyses were conducted to assess their relationship. Area under the receiver operating characteristic (AUROC) was calculated to assess the discriminatory ability of homeostatic model assessment of IR for advanced lobular inflammation (LI).

RESULTS

We observed higher serum level of alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, and low-density lipoprotein as HOMA-IR increased. HOMA-IR is significantly associated with severity of LI (odds ratio = 1.222, 95% confidence interval = 1.135-1.315, P < 0.001), similar association remained after adjusting for age, BMI, hemoglobin A1c, alanine aminotransferase, aspartate aminotransferase, low-density lipoprotein, high-density lipoprotein, and triglycerides (odds ratio = 1.205, 95% confidence interval = 1.102-1.317, P < 0.001). HOMA-IR is discriminant of LI with AUROC = 0.832 and cutoff = 2.995 (sensitivity = 0.938, specificity = 0.569).

CONCLUSION

This study demonstrated a strong and independent association of HOMA-IR with the severity of liver inflammation by histological evaluation in NAFLD patients without diabetes or metabolic syndrome, and its possible role in diagnosis of LI could be translated into clinical assessment of NAFLD patients with uncertainty of nonalcoholic steatohepatitis progression.

Comparative Effects and Mechanisms of Chitosan and Its Derivatives on Hypercholesterolemia in High-Fat Diet-Fed Rats

The present study investigated and compared the effects of different molecular weights of chitosan (high molecular weight chitosan (HC) and low molecular weight chitosan (LC)) and its derivatives (chitosan oligosaccharide (CO)) on cholesterol regulation in high-fat (HF) diet-fed rats. A diet supplementation of 5% HC, 5% LC, or 5% CO for 8 weeks showed hypocholesterolemic potential in HF diet-fed rats. Unexpectedly, a 5% CO-supplemented diet exerted hepatic damage, producing increased levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and tumor necrosis factor-alpha (TNF-α). The supplementation of HC and LC, unlike CO, significantly decreased the hepatic total cholesterol (TC) levels and increased the fecal TC levels in HF diet-fed rats. The hepatic protein expression of the peroxisome proliferator-activated receptor-α (PPARα) in the HF diet-fed rats was markedly decreased, which could be significantly reversed by both HC and LC, but not CO, supplementation. Unlike the supplementation of CO, both HC and LC supplementation could effectively reverse the HF-inhibited/induced gene expressions of the low-density lipoprotein receptor (LDLR) and cholesterol 7α-hydroxylase (CYP7A1), respectively. The upregulated intestinal acyl-CoA cholesterol acyltransferase 2 (ACAT2) protein expression in HF diet-fed rats could be reversed by HC and LC, but not CO, supplementation. Taken together, a supplementation of 5% CO in HF diet-fed rats may exert liver damage via a higher hepatic cholesterol accumulation and a higher intestinal cholesterol uptake. Both HC and LC effectively ameliorated the hypercholesterolemia and regulated cholesterol homeostasis via the activation and inhibition of hepatic (AMPKα and PPARα) and intestinal (ACAT2) cholesterol-modulators, respectively, as well as the modulation of downstream signals (LDLR and CYP7A1).

Efficacy and Mechanism of Polymerized Anthocyanin from Grape-Skin Extract on High-Fat-Diet-Induced Nonalcoholic Fatty Liver Disease

We investigated the therapeutic potential of polymerized anthocyanin (PA) on a nonalcoholic fatty liver disease (NAFLD) model in mice. C57BL/6 mice were fed a high-fat diet (HFD) for 8 weeks to establish the NAFLD mouse model and randomly divided into four groups: control diet (con), NAFLD mice treated with saline (NAFLD), NAFLD mice treated with PA (PA), and NAFLD mice treated with orlistat (Orlistat) for four weeks. Mice were euthanized at the end of the four weeks. Total cholesterol (TC) and triglyceride (TG) levels were estimated, and pathological changes in the liver, white adipose tissue, and signaling pathways related to lipid metabolism were evaluated. Results revealed that the body, liver, and white fat weight of the NAFLD group was significantly increased compared to that of the con group, while that of the PA group showed significant reduction. NAFLD led to an increase in blood lipids in mice (except for HDL). Conversely, PA effectively reduced TC and LDL-C. Compared to the control group, the degree of steatosis in the mice of PA group was decreased. Moreover, PA also regulated the NAFLD signaling pathway. In agreement with improved lipid deposition, PA supplementation inhibited the activation of inflammatory pathways, depressing oxidative stress through increased antioxidant levels, and increasing β-oxidation to inhibit mitochondrial dysfunction. Taken together, our results demonstrate that PA can improve the liver function of NAFLD mice, regulating blood lipids, reducing liver-fat accumulation, and regulating lipid metabolism.

Protective Effect of Hepatitis B Against Metabolic Syndrome in Patients with Nonalcoholic Fatty Liver Disease But Not in Normal Individuals

Background: Both hepatitis B (HB) and nonalcoholic fatty liver disease (NAFLD) are related to metabolic syndrome (MetS); however, this relationship remains controversial. In this study, we determined the effects of NAFLD and HB infection on the risk of MetS among elderly individuals. Methods: In total, 24,500 individuals aged >65 years were enrolled; they were classified into four groups: normal individuals (N), patients with only HB infection without abnormal echogenicity (HB-alone), patients with only abnormal echogenicity or fatty liver alone (FL-alone), and patients with both HB infection and abnormal echogenicity (HB-FL). Results: After adjustment for age, compared with group N, men and women with NAFLD (FL-alone and HB-FL) had a significantly higher risk of MetS, whereas no significant difference was observed in the incidence of MetS between groups HB-alone and N. However, group HB-FL had a lower risk of MetS than did group FL-alone. HB infection (HB-alone and HB-FL) was associated with a lower risk of high triglycerides (TGs) and fasting plasma glucose (FPG) than HB infection absence (groups N and FL-alone) in men and women. Lower risk of TG derangement was observed in group HB-alone than in group N. In addition, both men and women in group HB-FL had a lower risk of TG and FPG abnormalities than in group FL-alone, whereas a decrease in incidence of high waist circumference and blood pressure was observed only in men. Conclusion: HB infection protects against MetS development, only in patients with HB infection and NAFLD, but not in normal individuals. Additional studies are warranted to clarify the pathogenesis.

Non-alcoholic fatty liver disease in lean individuals

Non-alcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease, encompassing a spectrum from non-alcoholic fatty liver to non-alcoholic steatohepatitis, which can progress to cirrhosis. It has recently been recognised that NAFLD also occurs in individuals who are not obese, especially in Asian populations. In these patients, NAFLD manifests at lower overall body mass index thresholds in the presence of increased visceral adipose tissue. Currently, the principles of clinical management are similar to those in obese individuals, although, in specific regions and clinical situations, unique aetiologies of NAFLD must be treated specifically.

Both WHR and FLI as Better Algorithms for Both Lean and Overweight/Obese NAFLD in a Chinese Population

GOALS

To compare current nonalcoholic fatty liver disease (NAFLD)-related algorithms to find suitable algorithms for NAFLD, especially lean NAFLD in middle-aged and elderly Chinese population.

BACKGROUND

NAFLD is the most common cause of chronic liver disease in the world today. Various algorithms based on obesity indicators, blood lipids, and liver enzymes, etc. have been developed to screen NAFLD.

MATERIALS AND METHODS

General, anthropometric and biochemical characteristics were collected. One-way analysis of variance and the χ test were applied to test the differences in continuous and categorical variables, respectively. Multivariable logistic regression analyses, adjusted by age, gender, body mass index, tobacco use, alcohol consumption, and physical activities, were used to investigate the associations between NAFLD-related algorithms and NAFLD. The accuracy and cut-off point of NAFLD-related algorithms to detect NAFLD were evaluated by area under the receiver operator characteristic curve and the maximum Youden index analysis, respectively.

RESULTS

In 8 NAFLD-related algorithms, the receiver operator characteristic of fatty liver index (FLI) and waist circumstance-to-height ratio (WHR) for NAFLD were in the whole (0.83 and 0.84), lean (0.74 and 0.74), and overweight/obese (0.71 and 0.72) population, respectively, which were higher than those of other algorithms. The cut-off points of WHR and FLI for NAFLD were different in the overall (0.50 and 20), lean (0.47 and 10), and overweight/obese (0.53 and 45) population.

CONCLUSIONS

WHR and FLI could be the most accurate of 8 algorithms for the noninvasive diagnosis of NAFLD in both lean and overweight/obese population.

Global liver disease burdens and research trends: Analysis from a Chinese perspective

Liver diseases affect millions of people worldwide. In most developed countries, the incidence of viral hepatitis is waning as a result of modern advances in disease prevention, diagnosis, and therapies. Expanded programmes for systematic immunisation against hepatitis B virus have also significantly brought down the number of new cases in many countries, including China. In contrast, with the improvement in living standards, the prevalence of metabolic liver diseases including non-alcoholic fatty liver disease and alcohol-related liver disease is set to rise, ultimately leading to more cases of end-stage liver diseases (liver failure, cirrhosis, and liver cancer). Over the past 30 years, visionary governments of major nations have provided strong incentives for basic/clinical research, vaccination programmes, and drug discovery and development in the field of hepatology. To get rid of her unflattering title as the "leader in liver diseases", China has also made a serious effort to initiate nationwide preventive measures for liver diseases, global partnerships, and mentoring programmes for young hepatologists. Instrumental to such progress is the continuous support of the National Natural Science Foundation of China (NSFC), which has helped hepatology to thrive in virtually all research directions within the country. In this article, we seek to provide stimulating glimpses into the evolving liver disease epidemiology, institutional research profiles, funding landscape, and drug development trends in China, with an attempt to compare her status and achievements with those of the United States, European countries, and Japan.

Yogurt improves insulin resistance and liver fat in obese women with nonalcoholic fatty liver disease and metabolic syndrome: a randomized controlled trial

BACKGROUND

Because consumption of conventional yogurt has beneficial effects in a healthy population, and insulin resistance (IR) is the mutual pathogenesis in nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS), we hypothesized that yogurt would ameliorate IR in patients with NAFLD and MetS.

OBJECTIVES

The aim of this study was to investigate the effects of yogurt on IR and secondary endpoints including liver fat, gut microbiota, and serum biomarkers of inflammation and oxidative stress in obese women with NAFLD and MetS.

METHODS

One hundred obese women aged 36-66 y with both NAFLD and MetS were randomly assigned to consume 220 g/d of either conventional yogurt or milk for 24 wk. At baseline and week 24, we measured anthropometric indices, serum glucose, insulin, lipids, and cytokines in all participants, and liver fat and gut microbiota in 20 participants randomly selected from each group.

RESULTS

Forty-eight participants from the yogurt group and 44 from the milk group completed the intervention. Compared with milk, yogurt significantly decreased the homeostasis model assessment of insulin resistance (-0.53; 95% CI: -1.03, -0.02), fasting insulin (-2.77 mU/L; 95% CI: -4.91, -0.63 mU/L), 2-h insulin (-25.5 mU/L; 95% CI: -33.0, -17.9 mU/L), 2-h area under the curve for insulin (-29.4 mU/L · h; 95% CI: -44.0, -14.8 mU/L · h), alanine aminotransferase (-4.65 U/L; 95% CI: -8.67, -0.64 U/L), intrahepatic lipid (-3.44%; 95% CI: -6.19%, -0.68%), and hepatic fat fraction (-3.48%; 95% CI: -6.34%, -0.63%). Yogurt also decreased serum LPS (-0.31 EU/mL; 95% CI: -0.48, -0.14 EU/mL), fibroblast growth factor 21 (-57.76 pg/mL; 95% CI: -86.32, -29.19 pg/mL), lipids, and biomarkers of inflammation and oxidative stress, and altered gut microbiota composition. Mediation analysis showed that yogurt may improve IR by reducing serum lipids, inflammation, oxidative stress, and LPS.

CONCLUSIONS

Yogurt was better than milk at ameliorating IR and liver fat in obese Chinese women with NAFLD and MetS, possibly by improving lipid metabolism, reducing inflammation, oxidative stress, and LPS, and changing the gut microbiota composition. This trial was registered at www.chictr.org.cn as ChiCTR-IPR-15006801.

Cardio-Metabolic Disorders in Non-Alcoholic Fatty Liver Disease

With the progressive epidemics of obesity, non-alcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease in adults and children. The increasing prevalence and incidence of NAFLD with advanced fibrosis is concerning because patients appear to experience higher non-liver-related morbidity and mortality than the general population. Recent clinical evidence suggests that NAFLD is directly associated with an increased risk of cardio-metabolic disorders. This mini review describes briefly the current understanding of the pathogenesis of NAFLD, summarizing the link between NAFLD and cardio-metabolic complications, focusing mainly upon ischemic stroke, type 2 diabetes mellitus (DM), hypertension, chronic kidney disease (CKD) and cardiac arrhythmias. In addition, it describes briefly the current understanding of the pathogenesis of NAFLD.

Non alcoholic fatty liver disease and risk of incident diabetes in subjects who are not obese

BACKGROUND AND AIMS

It is not known whether non alcoholic fatty liver disease (NAFLD) is a risk factor for diabetes in non obese, non centrally-obese subjects. Our aim was to investigate relationships between fatty liver, insulin resistance and a biomarker score for liver fibrosis with incident diabetes at follow up, in subjects who were neither obese nor centrally-obese.

METHODS AND RESULTS

As many as 70,303 subjects with a body mass index (BMI) < 25 kg/m2 and without diabetes were followed up for a maximum of 7.9 years. At baseline, fatty liver was identified by liver ultrasound, insulin resistance (IR) by homeostatic model assessment of insulin resistance (HOMA-IR) ≥2.0, and central obesity by waist circumference (waist circumference ≥90 cm (men) and ≥85 cm (women). The Fibrosis-4 (FIB-4 score) was used to estimate extent of liver fibrosis. Cox proportional hazards models adjusted for confounders were used to estimate hazard ratios (aHRs) for incident diabetes. As many as 852 incident cases of diabetes occurred during follow up (median [IQR] 3.71 [2.03] years). Mean ± SD BMI was 22.8 ± 1.8 and 21.7 ± 2.0 kg/m2 in subjects with and without diabetes at follow up. In subjects without central obesity and with fatty liver, aHRs (95% CI) for incident diabetes at follow up were 2.17 (1.56, 3.03) for men, and 2.86 (1.50,5.46) for women. Similar aHRs for incident diabetes occurred with fatty liver, IR and the highest quartile of FIB-4 combined, in men; and there was a non significant trend toward increased risk in women.

CONCLUSIONS

In normal weight, non-centrally obese subjects NAFLD is an independent risk factor for incident diabetes.

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.

Effects of aerobic exercise training on the risk factors for liver diseases in elderly women with obesity and impaired fasting glucose: A pilot study

[Purpose]

In the present pilot study, we aimed to investigate the effects of the Silverrobics exercise program, which is similar to aerobic dance, on the factors related to glucose metabolism and liver enzymes.

[Methods]

Eight elderly women with obesity and impaired fasting glucose participated in the Silverrobics exercise program (60 minutes per session for five times a week for 8 weeks). The program was conducted at 50–60% of the heart rate reserve at 1 to 2 weeks and at 60–80% of the heart rate reserve at 3 to 8 weeks. To verify the effect of this 8-week exercise program on glucose metabolism and liver enzymes, blood analysis at pre- and post-training was performed.

[Results]

After the Silverrobics exercise program, there were significant decreases in the glucose (p<0.05), glycated hemoglobin A1c (p<0.05), 1,5-anhydroglucitol (p<0.05), and insulin levels (p<0.01) and homeostatic model assessment of insulin resistance score (p<0.05). However, there were no significant effects on the liver enzymes, except for alkaline phosphatase. The alkaline phosphatase level increased after the Silverrobics exercise program (p<0.05).

[Conclusion]

Although the Silverrobics exercise program had no beneficial effects on the liver enzymes, it may play an important role in preventing liver diseases considering the effects on glucose metabolism.

Alcoholic and non-alcoholic steatohepatitis: global perspective and emerging science

Alcohol and high-fat diet are two major risk factors responsible for metabolic diseases, which are manifested as steatohepatitis and liver cancer in the liver, and chronic pancreatitis and pancreatic adenocarcinoma (PDAC) in the pancreas. These metabolic diseases are becoming increasingly prevalent around the globe, and more importantly, their two major etiologies commonly coexist to precipitate the disease processes. To highlight the importance of these metabolic diseases, Japanese Society of Gastroenterology (JSGE) and National Institute on Alcoholism and Alcohol Abuse of National Institute of Health cosponsored the JSGE's 7th International Forum jointly held with the 12th International Symposium on ALPD and Cirrhosis. Toward the main theme of "Frontiers in ASH, NASH, NBNC-HCC and PDAC", this platform showcased presentations by 12 invited international and Japanese speakers on brain-gut-liver interactions, emerging mechanisms of ASH and NASH, metabolic reprogramming, and new therapeutic targets for cirrhosis, HCC, and PDAC. This editorial discusses the most recent data on global statistics on how alcohol and obesity impact health and longevity as a prelude to a brief summary of the symposium presentations and discussions, primarily focusing on the first two session themes.

Whole-Exome Sequencing Identifies a Variant in Phosphatidylethanolamine N-Methyltransferase Gene to be Associated With Lean-Nonalcoholic Fatty Liver Disease

BACKGROUND AND AIM

Nonalcoholic fatty liver disease (NAFLD) is a spectrum of liver diseases with simple steatosis on one end and hepatocellular carcinoma on the other. Although obesity is a known risk factor for NAFLD, individuals with normal body mass index (BMI) also have hepatic fatty infiltration, now termed "lean-NAFLD". It represents a distinct entity with a strong underlying genetic component. The present study aimed to sequence the complete exonic regions of individuals with lean-NAFLD to identify germline causative variants associated with disrupted hepatic fatty acid metabolism, thereby conferring susceptibility to NAFLD.

METHODS

Whole blood was collected from patients with lean-NAFLD (n = 6; BMI < 23.0 kg/m²) and matched lean controls (n = 2; discovery set). Liver fat was assessed using acoustic radiation force impulse (ARFI) imaging. Patients with ultrasound-detected NAFLD (n = 191) and controls (n = 105) were part of validation set. DNA was isolated, and whole-exome sequencing (WES) was performed in the discovery cohort (Ion Proton™; Ion AmpliSeq™ Exome RDY Kit). Data were analyzed (Ion Reporter software; Life Technologies), and variants identified. Validation of variants was carried out (Taqman probes; Real time-PCR). Student's t test and Fisher's exact test were used to analyze the statistical significance.

RESULTS

Although WES identified ∼74,000 variants in individual samples, using various pipelines. variants in genes namely phosphatidylethanolamine N-methyltransferase (PEMT) and oxysterol-binding protein-related protein10 (OSBPL10) that have roles in dietary choline intake and regulation of cholesterol homeostasis, respectively, were identified (discovery set). Furthermore, significant differences were noted in BMI (p = 0.006), waist/hip circumference (p > 0.001), waist/hip ratio (p > 0.001), aspartate aminotransferase (p > 0.001), alanine aminotransferase (p > 0.001), and triglycerides (p = 0.002) between patients and controls. Validation of variants (rs7946-PEMT and rs2290532-OSBPL10) revealed that variant in PEMT but not OSBPL10 gene was associated (p = 0.04) with threefold increased risk of NAFLD in lean individuals.

CONCLUSION

Our results demonstrate the association of rs7946 with lean-NAFLD. WES may be an effective strategy to identify causative variants underlying lean-NAFLD.

[A Multifaceted Approach regarding the Association of the DsbA-L Gene with the Risk of Obesity-related Diseases Based on Clinical Pharmacogenetics]

Adiponectin, the most abundant adipose tissue-derived adipocytokine, improves insulin sensitivity and has anti-inflammatory properties. Disulfide-bond A oxidoreductase-like protein (DsbA-L) is a key molecule in the multimerization of adiponectin (i.e., activation of adiponectin). In mice, liver-specific knockout of the Dsba-L gene impaired the mitochondrial function in hepatocytes and exacerbated the high-fat-diet-induced fatty liver. In addition, the DsbA-L mRNA level is negatively correlated with body mass index (BMI) in humans. We recently investigated the clinical impact of the DsbA-L gene on lifestyle-related diseases in Japanese subjects. We confirmed the influence of the common DsbA-L rs1917760 polymorphism on the multimerization of adiponectin, as well as the association of the polymorphism with the risk of obesity and non-alcoholic fatty liver disease, using prediction models based on a non-linear mixed effect model and/or structural equation models among elderly participants in a health screening program. We also observed a decreasing effect of DsbA-L polymorphism on the DsbA-L mRNA level in peripheral blood mononuclear cells, and an increasing effect of the polymorphism on the prevalence of excessive weight among schizophrenia patients at a high risk for obesity. These findings suggest that DsbA-L may be a key molecule associated with the development and progression of obesity and its related diseases. Therefore, genotyping the DsbA-L polymorphism and identifying patients at a high risk of developing obesity may help prevent obesity and its complications by facilitating targeted prevention and treatment programs for high-risk individuals.

Whole-Exome Sequencing Identifies a Variant in Phosphatidylethanolamine N-Methyltransferase Gene to be Associated With Lean-Nonalcoholic Fatty Liver Disease

BACKGROUND AND AIM

Nonalcoholic fatty liver disease (NAFLD) is a spectrum of liver diseases with simple steatosis on one end and hepatocellular carcinoma on the other. Although obesity is a known risk factor for NAFLD, individuals with normal body mass index (BMI) also have hepatic fatty infiltration, now termed "lean-NAFLD". It represents a distinct entity with a strong underlying genetic component. The present study aimed to sequence the complete exonic regions of individuals with lean-NAFLD to identify germline causative variants associated with disrupted hepatic fatty acid metabolism, thereby conferring susceptibility to NAFLD.

METHODS

Whole blood was collected from patients with lean-NAFLD (n = 6; BMI < 23.0 kg/m²) and matched lean controls (n = 2; discovery set). Liver fat was assessed using acoustic radiation force impulse (ARFI) imaging. Patients with ultrasound-detected NAFLD (n = 191) and controls (n = 105) were part of validation set. DNA was isolated, and whole-exome sequencing (WES) was performed in the discovery cohort (Ion Proton™; Ion AmpliSeq™ Exome RDY Kit). Data were analyzed (Ion Reporter software; Life Technologies), and variants identified. Validation of variants was carried out (Taqman probes; Real time-PCR). Student's t test and Fisher's exact test were used to analyze the statistical significance.

RESULTS

Although WES identified ∼74,000 variants in individual samples, using various pipelines. variants in genes namely phosphatidylethanolamine N-methyltransferase (PEMT) and oxysterol-binding protein-related protein10 (OSBPL10) that have roles in dietary choline intake and regulation of cholesterol homeostasis, respectively, were identified (discovery set). Furthermore, significant differences were noted in BMI (p = 0.006), waist/hip circumference (p > 0.001), waist/hip ratio (p > 0.001), aspartate aminotransferase (p > 0.001), alanine aminotransferase (p > 0.001), and triglycerides (p = 0.002) between patients and controls. Validation of variants (rs7946-PEMT and rs2290532-OSBPL10) revealed that variant in PEMT but not OSBPL10 gene was associated (p = 0.04) with threefold increased risk of NAFLD in lean individuals.

CONCLUSION

Our results demonstrate the association of rs7946 with lean-NAFLD. WES may be an effective strategy to identify causative variants underlying lean-NAFLD.

Lean non-alcoholic fatty liver disease patients had comparable total caloric, carbohydrate, protein, fat, iron, sleep duration and overtime work as obese non-alcoholic fatty liver disease patients

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD) is a multifactorial disease that involves a complex interaction between genetics, diet, and lifestyle. Although closely related with obese subjects, it is also common in lean humans. This study aimed to characterize the diet and lifestyle of lean and obese NAFLD patients in China.

METHODS

To characterize the diet and lifestyle of lean and obese NAFLD patients, we conducted a matched case-control study that included 351 Chinese adults. General characteristics, dietary intake, and lifestyle were gathered by using a valid and reliable dietary questionnaire. We compared the dietary intake and lifestyle between lean and obese NAFLD patients.

RESULTS

All NAFLD patients had more total caloric, calorigenic nutrients (carbohydrate, fat, and protein), grain, potato, fruit, and iron with higher levels of waist circumference and overtime work but shorter sleep duration than their corresponding controls. Particularly, lean NAFLD patients consumed comparable total caloric, calorigenic nutrients, iron, sleep duration, and overtime work as obese NAFLD patients, though they consumed lower levels of grain, potato, and fruit (lean NAFLD patients vs. obese NAFLD patients: mean ± SD, g/day grain: 291.8 ± 83.8, 365.2 ± 89.0; potato: 63.5 ± 33.1, 80.4 ± 37.6; fruit: 324.3 ± 148.4, 414.0 ± 220.4; P < 0.0001).

CONCLUSION

Non-alcoholic fatty liver disease patients had higher total caloric, calorigenic nutrients, grain, potato, fruit, iron, and overtime work but shorter sleep duration. Lean NAFLD patients had comparable total caloric, calorigenic nutrients, iron, sleep duration, and overtime work as obese NAFLD patients. These features could be used to the nutritional education and therapeutic guidance for lean NAFLD patients in the future.

Patients With Lean Nonalcoholic Fatty Liver Disease Are Metabolically Abnormal and Have a Higher Risk for Mortality

IN BRIEF Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized and common cause of chronic liver disease worldwide. Although most patients with NAFLD are obese, a smaller group of NAFLD patients are lean. This study explored the long-term outcomes of lean patients with NAFLD in the United States. Compared to lean individuals without NAFLD, lean people with NAFLD were significantly more likely to be older and male and had higher comorbidities (i.e., diabetes, hyperlipidemia, hypertension, metabolic syndrome, chronic kidney disease, and cardiovascular disease). The presence of NAFLD in lean individuals was independently associated with increased risk of all-cause and cardiovascular mortality.

Lean non-alcoholic fatty liver disease (lean NAFLD): characteristics, metabolic outcomes and risk factors from a 7-year prospective, community cohort study from Sri Lanka

INTRODUCTION

While patients with non-alcoholic fatty liver disease (NAFLD) are mostly overweight or obese, some are lean.

METHODS

In a community-based follow-up study (baseline and follow-up surveys performed in 2007 and 2014), we investigated and compared the clinical characteristics, body composition, metabolic associations and outcomes, and other risk factors among individuals with lean (BMI < 23 kg/m²) NAFLD, non-lean (BMI ≥ 23 kg/m²) NAFLD and those without NAFLD. To investigate associations of selected genetic variants, we performed a case-control study between lean NAFLD cases and lean non-NAFLD controls.

RESULTS

Of the 2985 participants in 2007, 120 (4.0%) had lean NAFLD and 816 (27.3%) had non-lean NAFLD. 1206 (40.4%) had no evidence of NAFLD (non-NAFLD). Compared to non-lean NAFLD, lean NAFLD was commoner among males (p < 0.001), and had a lower prevalence of hypertension (p < 0.001) and central obesity (WC < 90 cm for males, < 80 cm for females) (p < 0.001) without prominent differences in the prevalence of other metabolic comorbidities at baseline survey. Of 2142 individuals deemed as either NAFLD or non-NAFLD in 2007, 704 NAFLD individuals [84 lean NAFLD, 620 non-lean NAFLD] and 834 individuals with non-NAFLD in 2007 presented for follow-up in 2014. There was no difference in the occurrence of incident metabolic comorbidities between lean NAFLD and non-lean NAFLD. Of 294 individuals who were non-NAFLD in 2007 and lean in both 2007 and 2014, 84 (28.6%) had developed lean NAFLD, giving an annual incidence of 4.1%. Logistic regression identified the presence of diabetes at baseline, increase in weight from baseline to follow-up and a higher educational level as independent risk factors for the development of incident lean NAFLD. NAFLD association of PNPLA3 rs738409 was more pronounced among lean individuals (one-tailed p < 0.05) compared to the whole cohort sample.

CONCLUSION

Although lean NAFLD constitutes a small proportion of NAFLD, the risk of developing incident metabolic comorbidities is similar to that of non-lean NAFLD. A PNPLA3 variant showed association with lean NAFLD in the studied population. Therefore, lean NAFLD also warrants careful evaluation and follow-up.

Non-alcoholic fatty liver disease and hypertension: coprevalent or correlated?

OBJECTIVE

To provide a comprehensive review summarizing the existing evidence on the association between nonalcoholic fatty liver disease (NAFLD) and hypertension (HT) independent of other components of metabolic syndrome.

METHODS

We searched the literature through Medline and the Cochrane Library for studies evaluating the relationship between hypertension and fatty liver disease.

RESULTS

Studies testing this association are limited, but agree that HT and fatty liver disease are inter-related independent of other components of the metabolic syndrome such as obesity and diabetes mellitus. Clinical evidence shows that NAFLD is associated with new-onset HT, whereas increased blood pressure is related to the development of fatty liver disease and the possible subsequent progression to liver fibrosis. Insulin resistance and activation of the renin-angiotensin-aldosterone system (RAAS) might provide potential pathophysiologic links between these clinical entities. Until further evidence is available, patients with HT should be meticulously evaluated and treated for fatty liver disease and vice versa. RAAS inhibitors have been tested in NAFLD, presenting a favorable profile by decreasing insulin resistance and fibrosis progression.

CONCLUSION

NAFLD and HT are associated independent of traditional cardiovascular risk factors. Insulin resistance appears to be the main linking mechanism. Although RAAS inhibitors are the most beneficial treatment option for HT in patients with NAFLD, randomized studies on the administration of these agents in HT patients with NAFDL are warranted to provide optimal treatment options in these high cardiovascular risk individuals.

Vitamin D supplementation for the treatment of non-alcoholic fatty liver disease: A randomized double blind placebo controlled trial

BACKGROUND

Low serum vitamin D has been associated with metabolic syndrome and Non-alcoholic fatty liver disease (NAFLD). This study aimed to investigate the impact of vitamin D supplementation in treatment of patients with NAFLD.

METHODS

In a double blind, randomized, placebo controlled trial patients with NAFLD were randomized to receive one weekly pearl of placebo, 50,000 U vitamin D3 (cholecalciferol) pearl per week and 0.25 mg calcitriol (1,25 dihydroxycholecalciferol) pearl per day for 3 months.

RESULTS

106 NAFLD patients were randomized to receive calcitriol, vitamin D3 and placebo pearls for 12 weeks and data for 91 patients were analyzed. After 12 weeks of treatment, serum alkaline phosphatase levels was significantly decreased from baseline levels in vitamin D and calcitriol treated groups (P < 0.05). Serum and gamma glutamyl transferase (GGT) level was also significantly decreased compared to the baseline levels after 12 weeks of treatment with vitamin D. There was no statistically significant difference between placebo, calcitriol, vitamin D groups in terms of serum aminotransferase, alkaline phosphatase, serum GGT and lipid profile (P > 0.05).

CONCLUSION

While significant reduction of serum alkaline phosphatase and GGT were seen with vitamin D and calcitriol supplementation from baseline levels, no beneficial effects was seen when comparing vitamin D, calcitriol and placebo groups at the end of trial.

Prevalence of Suspected Nonalcoholic Fatty Liver Disease in Lean Adolescents in the United States

OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) can develop in lean subjects referred to as lean NAFLD. We aim to evaluate the prevalence and risk factors of NAFLD in lean adolescents in the United States (US).

METHODS

Cross sectional data from 1482 lean subjects (body mass index <85th percentile) ages between 12 and 18 years, who were enrolled in the National Health and Examination Survey during the 2005 to 2014 cycles were included. We defined suspected NAFLD as alanine aminotransferase >25.8 U/L for boys and >22.1 U/L for girls; hypertriglyceridemia as triglycerides ≥150 mg/dL; low HDL as HDL <40 mg/dL and insulin resistance (IR) as homeostatic model assessment of IR ≥3.

RESULTS

The mean weighted prevalence of suspected NAFLD among lean adolescents during 2005 to 2014 cycles was 8% (95% CI 6.2-9.9). Lean subjects with suspected NAFLD were significantly older compared with lean non-NAFLD subjects (15.5 vs 15 years, P value <0.05). Low HDL (15.5% vs 6.8%; P value 0.016) and hypertriglyceridemia (10% vs 3.9%; P value 0.028) were also found to be more common among lean NAFLD subjects compared with their non-NAFLD counterparts. Presence of IR increased the risk of having suspected NAFLD by 4-fold among lean adolescents. Non-Hispanic black lean adolescents were less likely to have suspected NAFLD compared with non-Hispanic white lean adolescents.

CONCLUSIONS

The estimated prevalence of suspected NAFLD among lean adolescents in the US was found to be 8% with evidence of metabolic derangements such as low HDL, hypertriglyceridemia, and IR.

Risk factors and metabolic abnormality of patients with non-alcoholic fatty liver disease: Either non-obese or obese Chinese population

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) occurs not only in obese individuals but also in non-obese ones. The aim of this study was to focus on the association between NAFLD and metabolic events in a non-obese or obese Chinese population.

METHODS

Data collected from subjects registered at Taichung Veterans General Hospital from January to December 2009 were analyzed. The exclusion criteria were alcoholics, chronic hepatitis B or C. Patients included in analyses were assigned to four groups according to sonography of their liver (normal or NAFLD), and body mass index (BMI) levels (non-obese if BMI < 25 kg/m² or obese if BMI ≥ 25 kg/m²).

RESULTS

There were 745, 208, 770 and 285 patients enrolled in four groups labeled non-obese normal liver (group A), non-obese NAFLD (group B), obese normal liver (group C) and obese NAFLD (group D), respectively. The highest ratio of metabolic syndrome existed in the group B (26.9%), followed by group A (11.7%), group D (10.9%) and finally the group C (5.2%). The positive association with NAFLD in non-obese individuals was significant in triglyceride (OR = 1.01; 95% CI: 1.01-1.02) and glucose (OR = 1.02; 95% CI: 1.01-1.03), while the positive association with NAFLD in obese subjects was only significant in triglyceride (OR = 1.01; 95% CI: 1.01-1.02). The positive association was most significant in all cases (adjusted OR = 2.41; 95% CI: 1.78-3.24), especially in non-obese individuals (OR = 2.81; 95% CI: 1.92-4.12).

CONCLUSIONS

Non-obese NAFLD subjects displayed a higher proportion of metabolic abnormality. Hyperlipidemia and hyperglycemia had the most positive strength association with NAFLD.

Global burden of NAFLD and NASH: trends, predictions, risk factors and prevention

NAFLD is one of the most important causes of liver disease worldwide and will probably emerge as the leading cause of end-stage liver disease in the coming decades, with the disease affecting both adults and children. The epidemiology and demographic characteristics of NAFLD vary worldwide, usually parallel to the prevalence of obesity, but a substantial proportion of patients are lean. The large number of patients with NAFLD with potential for progressive liver disease creates challenges for screening, as the diagnosis of NASH necessitates invasive liver biopsy. Furthermore, individuals with NAFLD have a high frequency of metabolic comorbidities and could place a growing strain on health-care systems from their need for management. While awaiting the development effective therapies, this disease warrants the attention of primary care physicians, specialists and health policy makers.

Developmental Origins of Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of metabolic syndrome. Its prevalence is currently increasing not only in developed obese countries but also in developing countries. Recent findings from human cohorts and animal studies suggest that a nutritional imbalance in the early critical period is causatively associated with the incidence of NAFLD in later life. Based on the current theory of the developmental origins of health and disease (DOHaD), undernourishment and overnourishment in utero are both hypothesized to prime the predisposition for hepatic fat storage. Current knowledge on the developmental origins of NAFLD is introduced in this chapter.

Risk for development of severe liver disease in lean patients with nonalcoholic fatty liver disease: A long-term follow-up study

Most patients with nonalcoholic fatty liver disease (NAFLD) are overweight or obese. However, a significant proportion of patients have a normal body mass index (BMI), denoted as lean NAFLD. The long‐term prognosis of lean NAFLD is unclear. We conducted a cohort study of 646 patients with biopsy‐proven NAFLD. Patients were defined as lean (BMI < 25.0), overweight (BMI 25.0‐29.9), or obese (BMI ≥ 30.0) at the time of biopsy. Each case was matched for age, sex, and municipality to 10 controls. Overall mortality and development of severe liver disease were evaluated using population‐based registers. Cox regression models adjusted for age, sex, type 2 diabetes, and fibrosis stage were used to examine the long‐term risk of mortality and liver‐related events in lean and nonlean NAFLD. Lean NAFLD was seen in 19% of patients, while 52% were overweight and 29% were obese. Patients with lean NAFLD were older, had lower transaminases, lower stages of fibrosis, and lower prevalence of nonalcoholic steatohepatitis at baseline compared to patients with a higher BMI. During a mean follow‐up of 19.9 years (range 0.4‐40 years) representing 12,631 person years and compared to patients who were overweight, patients with lean NAFLD had no increased risk for overall mortality (hazard ratio 1.06; P =  0.73) while an increased risk for development of severe liver disease was found (hazard ratio 2.69; P =  0.007). Conclusion: Although patients with lean NAFLD have lower stages of fibrosis, they are at higher risk for development of severe liver disease compared to patients with NAFLD and a higher BMI, independent of available confounders. (Hepatology Communications 2018;2:48–57)

Liver and Cardiovascular Damage in Patients With Lean Nonalcoholic Fatty Liver Disease, and Association With Visceral Obesity

BACKGROUND & AIMS

Lean nonalcoholic fatty liver disease (NAFLD) is defined as NAFLD that develops in patients with a body mass index (BMI) less than 25 kg/m². We investigated the differences between lean NAFLD and NAFLD in overweight and obese persons, factors associated with the severity of liver and cardiovascular disease, and the effects of visceral obesity.

METHODS

We performed a retrospective cohort study of 669 consecutive patients with biopsy-proven NAFLD seen at 3 liver centers in Italy. We collected anthropometric, clinical, and biochemical data, as well as information on carotid atherosclerosis (artery intima-media thickness and plaque), liver histology (nonalcoholic steatohepatitis [NASH] and fibrosis), insulin resistance, and diabetes. Overweight was defined as a BMI of 25 to 29.9 kg/m², and obese was defined as a BMI of 30 kg/m² or greater. Patients were assigned to groups based on waist circumference, a marker of visceral obesity (low: men, <94 cm, women <80 cm; medium: men, 94-102 cm, women 80-88 cm; or high: men >102 cm, women >88 cm). DNA samples were analyzed for the rs738409 C>G (I148M in PNPLA3), the rs58542926 C>T (E167K in TM6SF2), and single-nucleotide polymorphisms. Variables in men and women were analyzed using chi-squared analysis and the Mann-Whitney or Kruskal-Wallis tests. Multiple linear or logistic regression analyses were adjusted for all the variables of clinical relevance or statistically significant at univariate analyses. The primary outcome was the difference in liver and cardiovascular disease between lean NAFLD and NAFLD in overweight and obese persons. Secondary outcomes were effects of visceral obesity, based on waist circumference, on hepatic, vascular, and metabolic features.

RESULTS

Significantly lower proportions of patients with lean NAFLD (143 patients; 43 women; mean age, 46 ± 13 y) had hypertension (P = .001), diabetes (P = .0001), and metabolic syndrome (P = .0001) than overweight or obese patients with NAFLD (526 patients; 149 women; mean age, 49 ± 12 y). Significantly lower proportions of patients with lean NAFLD had NASH (17% vs 40% of obese or overweight patients with NAFLD; P = .0001), fibrosis of F2 or higher (17% vs 42%; P = .0001), or carotid plaques (27% vs 39%; P = .03). Patients with lean NAFLD had significantly thinner carotid intima-media (0.74 ± 0.1 mm) than obese or overweight patients with NAFLD (0.84 ± 0.3 mm; P = .0001). There was no significant difference in the proportions of patients with rs738409 C>G in PNPLA3, but a significantly greater proportion of patients with lean NAFLD carried rs58542926 C>T in TM6SF2 (4%) than obese or overweight individuals with NAFLD (0.3%; P = .001). Of the 143 patients with lean NAFLD, 27 had grade 3 steatosis, 24 had a lobular inflammation score greater than 2, 10 had a ballooning score of 2, and 25 had a fibrosis score of 2 or higher. In patients with lean NAFLD, the only variable associated independently with NASH and a fibrosis score of 2 or higher was rs738409 C>G in PNPLA3. Patients with lean NAFLD and a medium waist circumference had a significantly higher risk of diabetes (odds ratio, 11; 95% confidence interval [CI], 1.2-106; P = .03) than overweight or obese patients with a similar waist circumference (odds ratio, 1.3; 95% CI, 0.4-4.2; P = .6). Lean and overweight or obese patients with high waist circumferences had significant increases in risk compared with patients with low and medium circumference and diabetes, hypertension, and fibrosis scores of 2 or higher.

CONCLUSIONS

In a retrospective study of patients with lean NAFLD vs obese or overweight persons with NAFLD, we found 20% of patients with lean NAFLD to have NASH, fibrosis scores of 2 or higher, and carotid atherosclerosis. Lean patients with rs738409 C>G in PNPLA3 should be monitored for liver disease progression; studies including large series of patients with lean NAFLD will clarify the possible role of TM6SF2 polymorphisms.

Non-alcoholic Fatty Liver Disease in Lean Subjects: Characteristics and Implications

Non-alcoholic fatty liver disease (NAFLD) is commonly diagnosed in obese subjects; however, it is not rare among lean individuals. Given the absence of traditional risk factors, it tends to remain under-recognised. The metabolic profiles of lean NAFLD patients are frequently comparable to those of obese NAFLD patients. Though results from several studies have been mixed, it has been generally revealed that lean subjects with NAFLD have minor insulin resistance compared to that in obese NAFLD. Several genetic variants are associated with NAFLD without insulin resistance. Some data suggest that the prevalence of steatohepatitis and advanced fibrosis do not differ significantly between lean and obese NAFLD; however, the former tend to have less severe disease at presentation. The underlying pathophysiology of lean NAFLD may be quite different. Genetic predispositions, fructose- and cholesterol-rich diet, visceral adiposity and dyslipidaemia have potential roles in the pathogenic underpinnings. Lean NAFLD may pose a risk for metabolic disturbances, cardiovascular morbidity or overall mortality. Secondary causes of hepatic steatosis are also needed to be ruled out in lean subjects with NAFLD. The effectiveness of various treatment modalities, such as exercise and pharmacotherapy, on lean NAFLD is not known. Weight loss is expected to help lean NAFLD patients who have visceral obesity. Further investigation is needed for many aspects of lean NAFLD, including mechanistic pathogenesis, risk assessment, natural history and therapeutic approach.

Free fatty acids profile among lean, overweight and obese non-alcoholic fatty liver disease patients: a case - control study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) given its association with obesity and diabetes may perhaps exert distinct free fatty acids (FFA) pattern, but the understanding of this phenomenon is limited. To this effect, we evaluated FFA profiles among healthy subjects and NAFLD patients stratified by body weight, to identify FFA valuable for early diagnosis of NAFLD.

METHODS

Serum FFA profiles of healthy and NAFLD (lean, overweight and obese) subjects was determined using gas chromatography-mass spectrometry (GC-MS) and distinctions in FFA patterns were evaluated using one-way ANOVA while Receiver operating characteristics (ROC) and logistic regression models were used to explore FFA significant for diagnosing NAFLD.

RESULTS

NAFLD patients presented significantly higher (P < 0.05) serum FFA profiles compared to healthy controls (HC). While total FFA profiles were insignificantly different between lean (2093.33 ± 558.11 μg/ml) and overweight (2420.81 ± 555.18 μg/ml) NAFLD patients, obese NAFLD (2739.01 ± 810.35 μg/ml) presented most significantly elevated (P < 0.05) total FFA profiles compared with HC. Of the four FFA; myristic acid (14:0), palmitoleic acid (16:1), γ-linolenic acid (γ-18:3) and cis-7,10,13,16,19-docosapentaenoic acid (22:5), selected in ROC analysis given their high Youden's index and AUC, only 14:0; 5.58(1.37, 22.76) and 16:1; 4.36(1.34, 14.13) had statistical significant odd ratios.

CONCLUSION

Our findings suggest 14:0 and 16:1 are promising for early diagnosis of NAFLD.

The Association between Food Group Consumption Patterns and Early Metabolic Syndrome Risk in Non-Diabetic Healthy People

We investigated the association between dietary habits/food group consumption patterns and early risk of metabolic syndrome (MetS), a main cause for metabolic disease. Study participants were recruited from the health promotion center in Dong-A University Hospital and public advertisement. Study subjects (n = 243, 21-80 years) were categorized into three groups: Super-healthy (MetS risk factor [MetS RF] = 0, n = 111), MetS-risk carriers (MetS RF = 1-2, n = 96), and MetS (MetS RF ≥ 3, n = 27). Higher regularity in dietary habits (breakfast-everyday, regular eating time, non-frequent overeating, and non-frequent eating-out) was observed in the Super-healthy group than in the MetS-risk carriers, and particularly in the MetS subjects. The relationship between food group consumption patterns and MetS-risk related parameters were investigated with adjustment for confounding factors. Fruit consumption was positively associated with HDL-cholesterol, and tended to be negatively associated with waist circumference, triglyceride, LDL-cholesterol, and insulin resistance (IR). The consumption of low-fat meats and fish, and vegetables was negatively associated with hs-CRP. Specifically, the consumption of sea-foods belonging to the low-fat fish was negatively associated with fasting glucose, hs-CRP, and interleukin (IL)-6. Anchovy/dried white baits consumption was negatively associated with fasting insulin and IR. Green-yellow vegetables consumption was negatively associated with fasting insulin, IR, and hs-CRP. On the other hand, sugars and fast-foods were positively associated with LDL-cholesterol. Additionally, fast-foods consumption was positively associated with hs-CRP and IL-6 levels. In conclusion, dietary habits/food group consumption patterns are closely associated with MetS-risk related parameters in Koreans. It may suggest useful information to educate people to properly select healthy foods for early prevention of MetS.

Systematic review with meta-analysis: risk factors for non-alcoholic fatty liver disease suggest a shared altered metabolic and cardiovascular profile between lean and obese patients

BACKGROUND

The pathogenesis of non-alcoholic fatty liver disease (NAFLD) is closely associated with the co-occurrence of multiple pathological conditions characterising the metabolic syndrome (MetS), obesity in particular. However, NAFLD also develops in lean subjects, whose risk factors remain poorly defined.

METHODS

We performed a meta-analysis of 15 studies, along with the data pertaining to our own population (n=336 patients). Data from lean (n=1966) and obese (n=5938) patients with NAFLD were analysed; lean (n=9946) and obese (n=6027) subjects without NAFLD served as controls.

RESULTS

Relative to the lean non-NAFLD controls, lean patients with NAFLD were older (3.79±0.72 years, P=1.36×10^-6 ) and exhibited the entire spectrum of the MetS risk factors. Specifically, they had a significant (P=10^-10 ) increase in plasma glucose levels (6.44±1.12 mg/dL) and HOMA-IR (0.52±0.094-unit increment), blood lipids (triglycerides: 48.37±3.6, P=10^-10 and total cholesterol: 7.04±3.8, mg/dL, P=4.2×10^-7 ), systolic (5.64±0.7) and diastolic (3.37±0.9) blood pressure (mm Hg), P=10^-10 , and waist circumference (5.88±0.4 cm, P=10^-10 ); values denote difference in means±SE. Nevertheless, the overall alterations in the obese group were much more severe when compared to lean subjects, regardless of the presence of NAFLD. Meta-regression suggested that NAFLD is a modifier of the level of blood lipids.

CONCLUSION

Lean and obese patients with NAFLD share a common altered metabolic and cardiovascular profile. The former, while having normal body weight, showed excess of abdominal adipose tissue as well as other MetS features.

Association between the hyperuricemia and nonalcoholic fatty liver disease risk in a Chinese population: A retrospective cohort study

Nonalcoholic fatty liver disease (NAFLD) is a common chronic disease associated with high levels of serum uric acid (SUA). However, whether this relationship applies in obese subjects has been unclear, and no cohort study has previously been conducted in non-obese subjects. We therefore performed a retrospective cohort study among employees of seven companies in China to investigate whether hyperuricemia was independently associated with NAFLD in obese and non-obese subjects, respectively. A total of 2383 initially NAFLD-free subjects were followed up for four years, and 15.2% (363/2383) developed NAFLD. Hyperuricemia subjects had a higher cumulative incidence than did those with normouricemia (29.0% vs. 12.9%, P<0.001). Cox proportional hazard regression analyses showed that baseline hyperuricemia was significantly associated with risk of developing NAFLD in non-obese subjects. This relationship was significantly independent of baseline age, gender, metabolic syndrome components, and other clinical variables (RR = 1.389, 95%CI: 1.051-2.099). However, this association did not exist in obese subjects (RR = 1.010, 95%CI: 0.649-1.571). The independent effect of hyperuricemia on NAFLD was stronger in females (RR = 2.138, 95%CI: 1.050-4.355) than in males (RR = 1.435, 95%CI: 1.021-2.018). In conclusion, further studies are needed to explore the different mechanisms between obese and non-obese subjects, and the reason hyperuricemia raises NAFLD risk in females more than in males.

Red blood cell count has an independent contribution to the prediction of ultrasonography-diagnosed fatty liver disease

BACKGROUND & AIMS

Red blood cell (RBC) indices have been demonstrated to be associated with fatty liver disease (FLD) and metabolic syndrome. However, controversy exists regarding the relationship of RBC indices with FLD to date and few has focused on RBC count. This study aimed to explore the association between RBC count and risk of FLD in Southern Chinese adults.

METHODS

A hospital-based cross-sectional study was performed in two hospital health examination centers, including information on ultrasonography-diagnosed FLD, anthropometric indices and biochemical measurements. Covariance analysis was used to evaluate group differences. After quintile classification of RBC counts, logistic regression analysis was conducted to evaluate the odds ratios (ORs) of FLD.

RESULTS

This study consisted of 8618 subjects (4137 men and 4481 women) aged between 20 and 89 years. FLD cases had higher RBC counts than non-FLD cases in both genders (P<0.001). The prevalence rates of FLD increased with the RBC quintiles in both genders (all P trend<0.001), and were higher in men than women. Binary logistic regression analysis showed positive association between RBC count and FLD, and the OR (95% confidence interval (CI)) were 2.56 (2.06-3.18) in men and 3.69 (2.74-4.98) in women, respectively, when comparing Q5 with Q1. Stratified analyses showed similar trends among subjects with and without FLD risk factors. Gender independent results were similar to gender dependent results.

CONCLUSIONS

Elevated RBC count is independently associated with high risk of FLD, suggesting that the RBC count may be a potential risk predictor for FLD.

Nonalcoholic fatty liver disease in Asia: emerging perspectives

As in the West, nonalcoholic fatty liver disease (NAFLD) is the commonest chronic liver disease in Asia, with a prevalence higher than 40 % in some countries. The risk factors for NAFLD development are similar to those in Western countries, including increased body mass index, diabetes, insulin resistance, and metabolic syndrome. NAFLD in Asians is associated with different extrahepatic manifestations involving the cardiovascular, gastrointestinal, and renal systems. A considerable proportion of Asians with NAFLD are described as having "lean" NAFLD. Present in approximately 20 % of the Asian population, lean NAFLD is closely linked with insulin resistance, diabetes, and other metabolic complications, but its association with disease progression to nonalcoholic steatohepatitis and cirrhosis remains to be defined. There is emerging evidence of the interactions of NAFLD with hepatitis B virus and hepatitis C virus infection in Asia. Unlike in Western countries, NAFLD constitutes only a minority of cirrhosis and hepatocellular carcinoma cases in Asia. Possible explanations are the lower prevalence of obesity and the overwhelming problem of viral hepatitis in Asia. With aging of the obesity cohort in Asia, NAFLD-related liver complications are expected to increase.

Clinical and Metabolic Characterization of Lean Caucasian Subjects With Non-alcoholic Fatty Liver

OBJECTIVES

Non-alcoholic fatty liver disease (NAFLD) is closely linked to obesity; however, 5-8% of lean subjects also have evidence of NAFLD. We aimed to investigate clinical, genetic, metabolic and lifestyle characteristics in lean Caucasian subjects with NAFLD.

METHODS

Data from 187 subjects allocated to one of the three groups according to body mass index (BMI) and hepatic steatosis on ultrasound were obtained: lean healthy (BMI≤25 kg/m², no steatosis, N=71), lean NAFLD (BMI≤25 kg/m², steatosis, N=55), obese NAFLD (BMI≥30 kg/m², steatosis; N=61). All subjects received a detailed clinical and laboratory examination including oral glucose tolerance test. The serum metabolome was assessed using the Metabolomics AbsoluteIDQ p180 kit (BIOCRATES Life Sciences). Genotyping for single-nucleotide polymorphisms (SNPs) associated with NAFLD was performed.

RESULTS

Lean NAFLD subjects had fasting insulin concentrations similar to lean healthy subjects but had markedly impaired glucose tolerance. Lean NAFLD subjects had a higher rate of the mutant PNPLA3 CG/GG variant compared to lean controls (P=0.007). Serum adiponectin concentrations were decreased in both NAFLD groups compared to controls (P<0.001 for both groups) The metabolomics study revealed a potential role for various lysophosphatidylcholines (lyso-PC C18:0, lyso-PC C17:0) and phosphatidylcholines (PCaa C36:3; false discovery rate (FDR)-corrected P-value<0.001) as well as lysine, tyrosine, and valine (FDR<0.001).

CONCLUSIONS

Lean subjects with evidence of NAFLD have clinically relevant impaired glucose tolerance, low adiponectin concentrations and a distinct metabolite profile with an increased rate of PNPLA3 risk allele carriage.

Non-alcoholic fatty liver disease with and without metabolic syndrome: Different long-term outcomes

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome (MetS) are both shown to increase the risk of cardiovascular diseases and type 2 diabetes. However, there is a great overlap between these two diseases. The present study was aimed to examine the cardiovascular and metabolic prognosis of non-alcoholic fatty liver disease with and without metabolic syndrome.

METHODS

Middle-aged subjects (n=958) were divided into four subgroups, those with NAFLD and MetS, those with NAFLD or MetS, and healthy controls. The baseline characteristics of the subgroups were analyzed. The follow-up time for cardiovascular events was about 16years. After approximately 21years the cardiac ultrasound and laboratory parameters were re-analyzed and new type 2 diabetes cases were recorded.

RESULTS

Those with both diseases were at the greatest risk for cardiovascular events (p<0.001). Compared to healthy controls, only those with MetS, with or without NAFLD, were at increased risk for the development of type 2 diabetes (p<0.001) and for an increase in left ventricular mass index (p=0.001 and p=0.005, respectively). The cardiovascular and metabolic risk in subjects with NAFLD only was quite similar to that in healthy controls. The I148M variant of the patatin-like phospholipase domain-containing 3 gene (PNPLA3 polymorphism) was most present in those with NAFLD only (p=0.008).

CONCLUSIONS

NAFLD with MetS implies a considerable risk for cardiovascular diseases, type 2 diabetes and the increase of left ventricular mass index whereas NAFLD without MetS does not.

Editorial: "Lean" NAFLD: Metabolic Obesity with Normal BMI… Is It in the Genes?

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. "Lean" NAFLD represents a patient subpopulation with hepatic steatosis evident on imaging with normal BMI. This paper by Feldman and Eder et al. illustrates the mild but clear metabolic differences and genetic connections in Caucasian lean NAFLD patients compared with obese NAFLD and healthy controls. Their findings highlight key similarities of lean and obese NAFLD compared with lean healthy subjects. This paper characterizes "lean" NAFLD as a unique phenotype with specific genetic associations deserving of further investigation in the greater scheme of elucidating the pathophysiology of fatty liver.

Pathogenesis of Nonalcoholic Steatohepatitis: Interactions between Liver Parenchymal and Nonparenchymal Cells

Nonalcoholic fatty liver disease (NAFLD) is the most common type of chronic liver disease in the Western countries, affecting up to 25% of the general population and becoming a major health concern in both adults and children. NAFLD encompasses the entire spectrum of fatty liver disease in individuals without significant alcohol consumption, ranging from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH) and cirrhosis. NASH is a manifestation of the metabolic syndrome and hepatic disorders with the presence of steatosis, hepatocyte injury (ballooning), inflammation, and, in some patients, progressive fibrosis leading to cirrhosis. The pathogenesis of NASH is a complex process and implicates cell interactions between liver parenchymal and nonparenchymal cells as well as crosstalk between various immune cell populations in liver. Lipotoxicity appears to be the central driver of hepatic cellular injury via oxidative stress and endoplasmic reticulum (ER) stress. This review focuses on the contributions of hepatocytes and nonparenchymal cells to NASH, assessing their potential applications to the development of novel therapeutic agents. Currently, there are limited pharmacological treatments for NASH; therefore, an increased understanding of NASH pathogenesis is pertinent to improve disease interventions in the future.

Advances in research of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) has become the most common liver disease worldwide. It is related with increased morbidity and mortality of cirrhosis and hepatocellular carcinoma (HCC); however, its main health implications are increased risks of developing type 2 diabetes (T2D), cardiovascular diseases and malignancies. This paper reviews the advances in research of NAFLD in terms of epidemiology, risk factors, assessment of disease progression and risks for combined cardiovascular diseases and/or T2D as well as management.

Associations between Dietary Nutrient Intakes and Hepatic Lipid Contents in NAFLD Patients Quantified by ¹H-MRS and Dual-Echo MRI

Dietary habits are crucial in the progression of hepatic lipid accumulation and nonalcoholic fatty liver disease (NAFLD). However, there are limited studies using ¹H-magnetic resonance spectroscopy (¹H-MRS) and dual-echo in-phase and out-phase magnetic resonance spectroscopy imaging (dual-echo MRI) to assess the effects of dietary nutrient intakes on hepatic lipid contents. In the present study, we recruited 36 female adults (NAFLD:control = 19:17) to receive questionnaires and medical examinations, including dietary intakes, anthropometric and biochemical measurements, and ¹H-MRS and dual-echo MRI examinations. NAFLD patients were found to consume diets higher in energy, protein, fat, saturated fatty acid (SFA), and polyunsaturated fatty acid (PUFA). Total energy intake was positively associated with hepatic fat fraction (HFF) and intrahepatic lipid (IHL) after adjustment for age and body-mass index (BMI) (HFF: β = 0.24, p = 0.02; IHL: β = 0.38, p = 0.02). Total fat intake was positively associated with HFF and IHL after adjustment for age, BMI and total energy intake (HFF: β = 0.36, p = 0.03; IHL: β = 0.42, p = 0.01). SFA intake was positively associated with HFF and IHL after adjustments (HFF: β = 0.45, p = 0.003; IHL: β = 1.16, p = 0.03). In conclusion, hepatic fat content was associated with high energy, high fat and high SFA intakes, quantified by ¹H-MRS and dual-echo MRI in our population. Our findings are useful to provide dietary targets to prevent the hepatic lipid accumulation and NAFLD.