Extra-hepatic manifestations and complications of nonalcoholic fatty liver disease

Multi-system diseases and death trajectory of metabolic dysfunction-associated fatty liver disease: findings from the UK Biobank

BACKGROUND

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a newly defined condition encompassing hepatic steatosis and metabolic dysfunction. However, the relationship between MAFLD and multi-system diseases remains unclear, and the time-dependent sequence of these diseases requires further clarification.

METHODS

After propensity score matching, 163,303 MAFLD subjects and 163,303 matched subjects were included in the community-based UK Biobank study. The International Classification of Diseases, Tenth Revision (ICD-10), was used to reclassify medical conditions into 490 and 16 specific causes of death. We conducted a disease trajectory analysis to map the key pathways linking MAFLD to various health conditions, providing an overview of their interconnections.

RESULTS

Participants aged 59 (51-64) years, predominantly males (62.5%), were included in the study. During the 12.9-year follow-up period, MAFLD participants were found to have a higher risk of 113 medical conditions and eight causes of death, determined through phenome-wide association analysis using Cox regression models. Temporal disease trajectories of MAFLD were established using disease pairing, revealing intermediary diseases such as asthma, diabetes, hypertension, hypothyroid conditions, tobacco abuse, diverticulosis, chronic ischemic heart disease, obesity, benign tumors, and inflammatory arthritis. These trajectories primarily resulted in acute myocardial infarction, disorders of fluid, electrolyte, and acid-base balance, infectious gastroenteritis and colitis, and functional intestinal disorders. Regarding death trajectories of MAFLD, malignant neoplasms, cardiovascular diseases, and respiratory system deaths were the main causes, and organ failure, infective disease, and internal environment disorder were the primary end-stage conditions. Disease trajectory analysis based on the level of genetic susceptibility to MAFLD yielded consistent results.

CONCLUSIONS

Individuals with MAFLD have a risk of a number of different medical conditions and causes of death. Notably, these diseases and potential causes of death constitute many pathways that may be promising targets for preventing general health decline in patients with MAFLD.

Bone Turnover Markers in Adults with Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

Objective

Previous studies suggested that the level of bone turnover markers (BTMs) could be altered in patients with nonalcoholic fatty liver disease (NAFLD). We aim to provide a comprehensive understanding on the associations between BTMs and NAFLD in adults with a meta-analysis.

Methods

Articles published up to January 31, 2023, were systematically searched in PubMed, Web of Science, Cochrane database, Embase, and CNKI. The search formula is as follows: "nonalcoholic fatty liver disease" combined with the terms that bone turnover markers such as "osteocalcin," "collagen type I trimeric cross-linked peptide," and "procollagen type I N-terminal peptide." Stata 15.0 software was used to calculate the pooled OR (95% CI) and perform the heterogeneity test, sensitivity analysis, and publication bias.

Results

We identified 18 studies with a total of 12,310 participants. Statistical differences were found between patients with NAFLD compared to the control group for osteocalcin (n = 15 studies; SMD: -0.69; 95% CI: -0.73--0.64; P=0.002), procollagen type I N-terminal propeptide (n = 5 studies; SMD: -0.40; 95% CI: -0.80--0.00; P=0.049), and collagen type I cross-linked C-telopeptide (n = 7 studies; SMD: -0.16; 95% CI: -0.23--0.09); P < 0.001).

Conclusion

Bone turnover markers were lower in patients with NAFLD compared to the control group.

Liver Fibrosis Marker and Postoperative Mortality in Patients Without Overt Liver Disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) can progress to advanced fibrosis, which, in the nonsurgical population, is associated with poor hepatic and extrahepatic outcomes. Despite its high prevalence, NAFLD and related liver fibrosis may be overlooked during the preoperative evaluation, and the role of liver fibrosis as an independent risk factor for surgical-related mortality has yet to be tested. The aim of this study was to assess whether fibrosis-4 (FIB-4), which consists of age, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and platelets, a validated marker of liver fibrosis, is associated with postoperative mortality in the general surgical population.

METHODS

A historical cohort of patients undergoing general anesthesia at an academic medical center between 2014 and 2018 was analyzed. Exclusion criteria included known liver disease, acute liver disease or hepatic failure, and alcohol use disorder. FIB-4 score was categorized into 3 validated predefined categories: FIB-4 ≤1.3, ruling out advanced fibrosis; >1.3 and <2.67, inconclusive; and ≥2.67, suggesting advanced fibrosis. The primary analytic method was propensity score matching (FIB-4 was dichotomized to indicate advanced fibrosis), and a secondary analysis included a multivariable logistic regression.

RESULTS

Of 19,861 included subjects, 1995 (10%) had advanced fibrosis per FIB-4 criteria. Mortality occurred intraoperatively in 15 patients (0.1%), during hospitalization in 272 patients (1.4%), and within 30 days of surgery in 417 patients (2.1%). FIB-4 ≥2.67 was associated with increased intraoperative mortality (odds ratio [OR], 3.63; 95% confidence interval [CI], 1.25-10.58), mortality during hospitalization (OR, 3.14; 95% CI, 2.37-4.16), and within 30 days from surgery (OR, 2.46; 95% CI, 1.95-3.10), after adjusting for other risk factors. FIB-4 was related to increased mortality in a dose-dependent manner for the 3 FIB-4 categories ≤1.3 (reference), >1.3 and <2.67, and ≥2.67, respectively; during hospitalization (OR, 1.89; 95% CI, 1.34-2.65 and OR, 4.70; 95% CI, 3.27-6.76) and within 30 days from surgery (OR, 1.77; 95% CI, 1.36-2.31 and OR, 3.55; 95% CI, 2.65-4.77). In a 1:1 propensity-matched sample (N = 1994 per group), the differences in mortality remained. Comparing the FIB-4 ≥2.67 versus the FIB-4 <2.67 groups, respectively, mortality during hospitalization was 5.1% vs 2.2% (OR, 2.70; 95% CI, 1.81-4.02), and 30-day mortality was 6.6% vs 3.4% (OR, 2.26; 95% CI, 1.62-3.14).

CONCLUSIONS

A simple liver fibrosis marker is strongly associated with perioperative mortality in a population without apparent liver disease, and may aid in future surgical risk stratification and preoperative optimization.

Correlation between Central Obesity and Liver Function in Young Adults—A Cross-Sectional Study

Background Visceral fat is a more accurate predictor of metabolic and cardiovascular disease risk than body fat alone. Although the liver function is associated with waist-to-hip ratio (WHR) in studies, this correlation is not well established in young central obese individuals. In this study, we examined the correlation between liver function parameters and central obesity in young obese subjects.

Methods Subjects with central obesity among the student and staff community between 18 and 40 years were recruited for the study after their written and informed consent. Male subjects whose WHR is above 0.90 and females above 0.85 were included. The liver function was assessed by estimating alanine transaminase (ALT), aspartate transaminase (AST), albumin, globulin, albumin:globulin ratio (A:G ratio), total bilirubin, direct bilirubin, and Gamma-glutamyl transferase (GGT). The data were analyzed using Pearson correlation to find the statistical significance between lung function parameters in centrally obese individuals with their WHR using SPSS version-16. A p-value less than 0.05 was considered the level of significance.

Results The results showed an insignificant correlation between the liver function parameters (p > 0.05) and WHR except for serum albumin (p < 0.021). The level of AST, ALT, total protein, globulin, A:G ratio, GGT, total Bilirubin, and direct bilirubin in young male and female central obese subjects have not deviated from the normal physiological range.

Conclusion The serum albumin level estimation will be considered an early indicator of metabolic disorder due to central obesity.

The triglyceride glucose-body mass index: a non-invasive index that identifies non-alcoholic fatty liver disease in the general Japanese population

Background

By identifying individuals at high risk for non-alcoholic fatty liver disease (NAFLD), interventional programs could be targeted more effectively. Some studies have demonstrated that triglyceride glucose-body mass index (TyG-BMI) showed an independent positive association with NAFLD. However, research on its diagnostic value in patients with suspected NAFLD is limited. In this study, we aimed to evaluate whether TyG-BMI was accurate in detecting NAFLD in the general Japanese population.

Methods

A cross-sectional study of 14,280 individuals who underwent a comprehensive health examination was conducted. Standard protocols were followed to collect anthropometric measurements, lab data, and ultrasonography features. All participants were randomly stratified into the development group (n = 7118) and validation group (n = 7162). The TyG-BMI was calculated. Following this, the diagnostic value of the TyG-BMI was evaluated based on the area under the receiver-operating characteristic curve (AUROC). Two cutoff points were selected and used to rule out or rule in the NALFD, and the specificity, sensitivity, negative predictive value, and positive predictive value were explored, respectively. In order to verify the stability of the results, external verification was performed.

Results

There were 1272 and 1243 NAFLD participants in the development and validation groups, respectively. The area under the ROC curve (AUC) of TyG-BMI was 0.888 (95% CI 0.876–0.896) and 0.884 (95% CI 0.875–0.894) for the training and validation group, respectively. Using the low TyG-BMI (182.2) cutoff, NAFLD could be excluded with high accuracy (negative predictive value: 96.9% in estimation and 96.9% in validation). The presence of NAFLD could effectively be determined by applying the high cutoff of TyG-BMI (224.0), as the positive predictive value of the estimation and validation groups is 70.7% and 70.1%, respectively. As a result of applying this model, 9996 (70%) of the 14,280 participants would not have undergone ultrasonography, with an accurate prediction of 9308 (93.1%). AUC was 0.874 for external validation using 183,730 Chinese non-obese participants. TyG-BMI was demonstrated to be an excellent diagnostic tool by both internal and external validation.

Conclusions

In conclusion, the present study developed and validated a simple, non-invasive, and cost-effective tool to accurately separate participants with and without NAFLD in the Japanese population, rendering ultrasonography for identifying NAFLD unnecessary in a substantial proportion of people.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03611-4.

Association between hypertriglyceridemic-waist phenotype and non-alcoholic fatty liver disease: a general population-based study

BACKGROUND

Hypertriglyceridemic-waist (HTGW) phenotype has been proposed as a practical tool for screening the risk of cardiovascular diseases and glycemic metabolic disease. This study sought to investigate the relationship between HTGW phenotype and non-alcoholic fatty liver disease (NAFLD).

METHODS

A total of 14,251 subjects who took part in health screening were enrolled in the study and NAFLD was diagnosed by abdominal ultrasound. According to triglyceride (TG) and waist circumference, the study population was divided into four phenotypes, in which HTGW phenotype was defined as TG ≥ 1.7 mmol/L and male waist circumference ≥ 90 cm or female waist circumference ≥ 80 cm. Multivariate logistic regression analysis was used to evaluate the relationship between HTGW phenotype and NAFLD.

RESULTS

In the current study, 2.43% of the subjects had HTGW phenotype, while the prevalence of NAFLD in subjects with HTGW phenotype was 77.81%. After full adjustment for covariates, compared with people with normal waist circumference and TG levels, the risk of NAFLD in people with normal TG levels but enlarged waist circumference increased by 39% [OR:1.39, 95%CI: 1.15, 1.68], in people with normal waist circumference but elevated TG levels increased by 96% [OR:1.96, 95%CI: 1.65, 2.33], and in subjects with HTGW phenotype increased by 160% [OR:2.60, 95%CI: 1.88, 3.58]. Additionally, further analysis suggested that there were significant interactions between age, height, BMI and NAFLD risk associated with TGW phenotypes. Receiver operating characteristic curves analysis suggested that the combination of TG and waist circumference further improved the diagnostic value for NAFLD.

CONCLUSIONS

HTGW phenotype is associated with NAFLD risk in the general population, which may be a novel and accessible indicator for NAFLD screening.

Metabolic Dysfunction-associated Fatty Liver Disease is Associated with Greater Impairment of Lung Function than Nonalcoholic Fatty Liver Disease

BACKGROUND AND AIMS

We compared lung function parameters in nonalcoholic fatty liver disease (NAFLD) and metabolic dysfunction-associated fatty liver disease (MAFLD), and examined the association between lung function parameters and fibrosis severity in MAFLD.

METHODS

In this cross-sectional study, we randomly recruited 2,543 middle-aged individuals from 25 communities across four cities in China during 2016 and 2020. All participants received a health check-up including measurement of anthropometric parameters, biochemical variables, liver ultrasonography, and spirometry. The severity of liver disease was assessed by the fibrosis (FIB)-4 score.

RESULTS

The prevalence of MAFLD was 20.4% (n=519) and that of NAFLD was 18.4% (n=469). After adjusting for age, sex, adiposity measures, smoking status, and significant alcohol intake, subjects with MAFLD had a significantly lower predicted forced vital capacity (FVC, 88.27±17.60% vs. 90.82±16.85%, p<0.05) and lower 1 s forced expiratory volume (FEV₁, 79.89±17.34 vs. 83.02±16.66%, p<0.05) than those with NAFLD. MAFLD with an increased FIB-4 score was significantly associated with decreased lung function. For each 1-point increase in FIB-4, FVC was diminished by 0.507 (95% CI: -0.840, -0.173, p=0.003), and FEV₁ was diminished by 0.439 (95% CI: -0.739, -0.140, p=0.004). The results remained unchanged when the statistical analyses was performed separately for men and women.

CONCLUSIONS

MAFLD was significantly associated with a greater impairment of lung function parameters than NAFLD.

Risk of hepatic and extrahepatic cancer in NAFLD: A population-based cohort study

BACKGROUND AND AIMS

Individuals with non-alcoholic fatty liver disease (NAFLD) may be at greater risk of cancer. This study aimed to investigate the risk of hepatic and extrahepatic cancer compared to the general population in a population-based cohort of patients with NAFLD.

METHODS

We used the Swedish National Patient Registry from 1987 to 2016 to identify patients with a NAFLD diagnosis and no prior cancer. All patients with NAFLD were compared to up to 10 controls matched for age, sex and living location. The primary outcome was the first occurrence of any cancer as ascertained from national registries. As secondary outcomes, we analysed the risk of pre-specified cancer subtypes. Cox regression models, adjusted for baseline diabetes, hypertension, hyperlipidaemia and chronic obstructive pulmonary disease were applied.

RESULTS

We identified 8415 patients with NAFLD. Over a median follow-up of 6.0 years (IQR 2.5-11.2 years), an increased risk for any cancer was found in patients with NAFLD compared to controls (9.7 vs. 8.6 cases per 1000 person-years): hazard ratio (HR) = 1.22 (95% confidence interval, CI = 1.12-1.33). The risk for hepatocellular carcinoma (HCC) was particularly high (adjusted HR, aHR = 12.18, 95% CI = 7.15-20.79). The risk for some other cancer subtypes increased (colorectal [aHR 1.38], kidney [aHR 2.12], bladder [aHR 2.51] and uterine [aHR 1.78]), but was low in absolute terms.

CONCLUSION

In this population-based cohort, NAFLD was associated with an increased risk of developing cancer (especially HCC). The absolute risk for other forms of cancer was generally comparable to the control population.

Remnant cholesterol/high-density lipoprotein cholesterol ratio is a new powerful tool for identifying non-alcoholic fatty liver disease

BACKGROUND

Remnant cholesterol/high-density lipoprotein cholesterol (RC/HDL-C) ratio has been shown to be a good predictor of metabolic disease risk, but no studies have further investigated the role of RC/HDL-C ratio in non-alcoholic fatty liver disease (NAFLD) patients.

METHODS

The participants were 14,251 adults who underwent a physical examination, all of whom underwent abdominal ultrasonography to determine whether they had NAFLD. Receiver operating characteristic curve analysis and multivariate logistic regression models were used to assess the association between the RC/HDL-C ratio and the risk of NAFLD.

RESULTS

Multivariate logistic regression analysis showed that after fully adjusting the confounding factors, the higher RC/HDL-C ratio was independently positively correlated with the risk of NAFLD. Interaction tests suggested that the effect of RC/HDL-C ratio on NAFLD was significantly affected by sex. Additionally, receiver operating characteristic curve analysis showed that the area under the curve of RC/HDL-C ratio for identifying NAFLD was 0.82, which was significantly higher than that of other conventional lipid parameters.

CONCLUSIONS

This study indicates for the first time that the higher RC/HDL-C ratio in the general population may be closely related to the increased risk of NAFLD.

Development of Thyroid Hormones and Synthetic Thyromimetics in Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the fastest-growing liver disease in the world. Despite targeted agents which are needed to provide permanent benefits for patients with NAFLD, no drugs have been approved to treat NASH. Thyroid hormone is an important signaling molecule to maintain normal metabolism, and in vivo and vitro studies have shown that regulation of the 3,5,3'-triiodothyronine (T3)/ thyroid hormone receptor (TR) axis is beneficial not only for metabolic symptoms but also for the improvement of NAFLD and even for the repair of liver injury. However, the non-selective regulation of T3 to TR subtypes (TRα/TRβ) could cause unacceptable side effects represented by cardiotoxicity. To avoid deleterious effects, TRβ-selective thyromimetics were developed for NASH studies in recent decades. Herein, we will review the development of thyroid hormones and synthetic thyromimetics based on TR selectivity for NAFLD, and analyze the role of TR-targeted drugs for the treatment of NAFLD in the future.

Association of remnant cholesterol with nonalcoholic fatty liver disease: a general population-based study

BACKGROUND

Remnant cholesterol (RC) mediates the progression of coronary artery disease, diabetic complications, hypertension, and chronic kidney disease. Limited information is available on the association of RC with nonalcoholic fatty liver disease (NAFLD). This study aimed to explore whether RC can be used to independently evaluate the risk of NAFLD in the general population and to analyze the predictive value of RC for NAFLD.

METHODS

The study included 14,251 subjects enrolled in a health screening program. NAFLD was diagnosed by ultrasound, and the association of RC with NAFLD was assessed using the receiver operating characteristic (ROC) curve and logistic regression equation.

RESULTS

Subjects with elevated RC had a significantly higher risk of developing NAFLD after fully adjusting for potential confounding factors (OR 1.77 per SD increase, 95% CI 1.64-1.91, P trend< 0.001). There were significant differences in this association among sex, BMI and age stratification. Compared with men, women were facing a higher risk of RC-related NAFLD. Compared with people with normal BMI, overweight and obesity, the risk of RC-related NAFLD was higher in thin people. In different age stratifications, when RC increased, young people had a higher risk of developing NAFLD than other age groups. Additionally, ROC analysis results showed that among all lipid parameters, the AUC of RC was the largest (women: 0.81; men: 0.74), and the best threshold for predicting NAFLD was 0.54 in women and 0.63 in men.

CONCLUSIONS

The results obtained from this study indicate that (1) in the general population, RC is independently associated with NAFLD but not with other risk factors. (2) Compared with traditional lipid parameters, RC has a better predictive ability for NAFLD in men.

Electrocardiographic Abnormalities in Patients With Spinal Cord Injury With Deranged Lipid Profile

Introduction Spinal cord injury (SCI) can lead to severe disability and neurogenic shock, arrhythmias, autonomic dysfunction, pressure ulcers, etc., of the autonomic nervous system. Therefore, in these patients, cardiovascular problems should be investigated frequently. This study was conducted to evaluate the electrocardiographic (ECG) abnormalities in patients with spinal cord injury having inappropriate lipid profiles and their relationship with each other. Materials and methods This cross-sectional study was held in the Internal Medicine Department of Mayo Hospital, Lahore, for a one-year duration from May 2020 to May 2021. It included 58 patients with spinal cord injury, 35 of whom had paraplegia, and 23 had tetraplegia. Fasting blood samples were taken for lipid profile analysis. Twelve-lead ECGs three times a day for one month were taken and analyzed in the context of previously available ECGs. Results Out of 58, the lipid profiles were found abnormal in 47 patients, 18 of whom had a normal ECG. The lipid profile was normal in 12, of which only one patient had ECG abnormalities. Cholesterol levels were found normal in 39 patients and deranged in 19 patients; low-density lipoproteins in nine patients, triglycerides in 18 patients, and high-density lipoprotein values in one patient were abnormal. Conclusions Sinus bradycardia was the most common ECG abnormality found in SCI patients with deranged lipid profiles. Further studies are needed in the future to validate the findings of this study.

Usefulness of the triglyceride glucose-body mass index in evaluating nonalcoholic fatty liver disease: insights from a general population

Background

Triglyceride glucose-body mass index (TyG-BMI) is a recently developed alternative indicator to identify insulin resistance. However, few studies have investigated the association between the TyG-BMI and nonalcoholic fatty liver disease (NAFLD). Therefore, this study aimed to study the relationship between NAFLD and the TyG-BMI in the general population and its predictive value.

Methods

A cross-sectional study was conducted on 14,251 general subjects who took part in a comprehensive health examination. The anthropological characteristics and many risk factors for NAFLD were measured.

Results

After fully adjusting for confounding variables, a stable positive correlation was found between NAFLD and the TyG-BMI (OR: 3.90 per SD increase; 95% CI: 3.54 to 4.29; P-trend< 0.00001). This positive correlation was not simply linear but a stable non-linear correlation. Additionally, obvious threshold effects and saturation effects were found, in which a threshold effect occurred when the TyG-BMI was between 100 and 150; when the TyG-BMI was between 300 and 400, the corresponding NAFLD risk appeared saturated. Furthermore, receiver operating characteristic analysis showed that the TyG-BMI could better predict the risk of NAFLD than other traditional indicators [TyG-BMI (AUC): 0.886; 95% CI: 0.8797–0.8927; P < 0.0001], particularly among young and middle-aged and non-obese people.

Conclusions

This epidemiological study is the first on the association between the TyG-BMI and NAFLD risk in the general population. In this large data set from the general population, the TyG-BMI showed an independent positive correlation with NAFLD. The discovery of the threshold effect and saturation effect between them provides a new idea to prevent and treat NAFLD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-021-01506-9.

Effects of Liraglutide on Nonalcoholic Fatty Liver Disease in Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

INTRODUCTION

Nonalcoholic fatty liver disease (NAFLD) is a common comorbidity of type 2 diabetes mellitus (T2DM), and no approved therapies are currently available. A meta-analysis was performed to investigate the effects of liraglutide on NAFLD in patients with T2DM.

METHODS

Medline (via PubMed), Embase (via Elsevier), and the Cochrane Central Register of Controlled Trials (CENTRAL) (via Cochrane Library) from inception to April 2020 were searched. After screening the literature and extracting data, we assessed the risk of bias of the eligible studies. The Cochrane Collaboration's RevMan software program was used for the statistical analysis.

RESULTS

Eleven trials involving 535 patients were included for the final analysis. Compared to the placebo or control group, liraglutide decreased liver fat (LF) (insulin: mean difference MD - 2.50, 95% confidence interval [CI] - 4.30 to - 0.70), body mass index (BMI) (placebo: MD - 1.13, 95% CI - 2.03 to - 0.23; pioglitazone: MD - 4.10, 95% CI - 6.27 to - 1.93; metformin: MD - 1.07, 95% CI - 2.06 to - 0.08; insulin: MD - 1.01, 95% CI - 1.60 to - 0.43), lipoproteins, including high-density (insulin: MD - 0.10, 95% CI - 0.15 to - 0.05) and low-density lipoproteins (MD - 0.26, 95% CI - 0.43 to - 0.10), glycated hemoglobin A1c (HbA1c) (placebo: MD - 0.86; 95% CI - 1.22 to - 0.51; insulin: MD - 0.22, 95% CI - 0.41 to  - 0.04), total cholesterol (placebo: MD - 0.34, 95% CI - 0.65 to - 0.03; metformin: MD  0.09, 95% CI 0.01-0.18), and triglycerides (placebo: MD - 0.29, 95% CI - 0.57 to - 0.01; insulin: MD - 0.80, 95% CI - 1.03 to - 0.57). Liraglutide may be associated with increased gastrointestinal reactions compared to pioglitazone.

CONCLUSION

These findings revealed that liraglutide decreased LF, BMI, lipids, or HbA1c in T2DM patients complicated with NAFLD, indicating its potential therapeutic efficacy.

Perspectives on Precision Medicine Approaches to NAFLD Diagnosis and Management

Precision medicine defines the attempt to identify the most effective approaches for specific subsets of patients based on their genetic background, clinical features, and environmental factors. Nonalcoholic fatty liver disease (NAFLD) encompasses the alcohol-like spectrum of liver disorders (steatosis, steatohepatitis with/without fibrosis, and cirrhosis and hepatocellular carcinoma) in the nonalcoholic patient. Recently, disease renaming to MAFLD [metabolic (dysfunction)-associated fatty liver disease] and positive criteria for diagnosis have been proposed. This review article is specifically devoted to envisaging some clues that may be useful to implementing a precision medicine-oriented approach in research and clinical practice. To this end, we focus on how sex and reproductive status, genetics, intestinal microbiota diversity, endocrine and metabolic status, as well as physical activity may interact in determining NAFLD/MAFLD heterogeneity. All these factors should be considered in the individual patient with the aim of implementing an individualized therapeutic plan. The impact of considering NAFLD heterogeneity on the development of targeted therapies for NAFLD subgroups is also extensively discussed.

Renaming NAFLD to MAFLD: Could the LDE System Assist in This Transition?

Our understanding of fatty liver syndromes and their relationship with the metabolic syndrome has improved over recent decades and, paralleling this, we are now at the dawn of the NAFLD (nonalcoholic fatty liver disease) to MAFLD (metabolic-associated fatty liver disease) transition. The pitfalls of NAFLD diagnosis, together with disappointing results in therapeutic trials, and the inconsistencies and risks inherent in a "negative" definition (such as "nonalcoholic") as opposed to a "positive" one (i.e., "metabolic") are predicted to facilitate the proposed renaming of NAFLD to MAFLD. However, a premature change of terminology would not necessarily address major unmet needs in this area, and may even become counterproductive. As an aid to selecting more homogeneous cohorts of patients, I propose the LDE (Liver, Determinants, Extra-hepatic) classification system which, in principle, may help to assess the natural course of disease as well as the efficacy of novel drugs in patients with NAFLD/MAFLD.

Semi-Quantitative Ultrasonographic Evaluation of NAFLD

Nonalcoholic fatty liver disease (NAFLD) embraces histopathological entities ranging from the relatively benign simple steatosis to the progressive form nonalcoholic steatohepatitis (NASH), which is associated with fibrosis and an increased risk of progression to cirrhosis and hepatocellular carcinoma. NAFLD is the most common liver disease and is associated with extrahepatic comorbidities including a major cardiovascular disease burden. The non-invasive diagnosis of NAFLD and the identification of subjects at risk of progressive liver disease and cardio-metabolic complications are key in implementing personalized treatment schedules and follow-up strategies. In this review, we highlight the potential role of ultrasound semiquantitative scores for detecting and assessing steatosis severity, progression of NAFLD, and cardio-metabolic risk. Ultrasonographic scores of fatty liver severity act as sensors of cardio-metabolic health and may assist in selecting patients to submit to second-line non-invasive imaging techniques and/or liver biopsy.

The American lifestyle-induced obesity syndrome diet in male and female rodents recapitulates the clinical and transcriptomic features of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis

The pathogenesis of nonalcoholic fatty liver disease (NAFLD) and the progression to nonalcoholic steatohepatitis (NASH) and increased risk of hepatocellular carcinoma remain poorly understood. Additionally, there is increasing recognition of the extrahepatic manifestations associated with NAFLD and NASH. We demonstrate that intervention with the American lifestyle-induced obesity syndrome (ALIOS) diet in male and female mice recapitulates many of the clinical and transcriptomic features of human NAFLD and NASH. Male and female C57BL/6N mice were fed either normal chow (NC) or ALIOS from 11 to 52 wk and underwent comprehensive metabolic analysis throughout the duration of the study. From 26 wk, ALIOS-fed mice developed features of hepatic steatosis, inflammation, and fibrosis. ALIOS-fed mice also had an increased incidence of hepatic tumors at 52 wk compared with those fed NC. Hepatic transcriptomic analysis revealed alterations in multiple genes associated with inflammation and tissue repair in ALIOS-fed mice. Ingenuity Pathway Analysis confirmed dysregulation of metabolic pathways as well as those associated with liver disease and cancer. In parallel the development of a robust hepatic phenotype, ALIOS-fed mice displayed many of the extrahepatic manifestations of NAFLD, including hyperlipidemia, increased fat mass, sarcopenia, and insulin resistance. The ALIOS diet in mice recapitulates many of the clinical features of NAFLD and, therefore, represents a robust and reproducible model for investigating the pathogenesis of NAFLD and its progression.NEW & NOTEWORTHY Nonalcoholic fatty liver disease (NAFLD) affects 30% of the general population and can progress to nonalcoholic steatohepatitis (NASH) and potentially hepatocellular carcinoma. Preclinical models rely on mouse models that often display hepatic characteristics of NAFLD but rarely progress to NASH and seldom depict the multisystem effects of the disease. We have conducted comprehensive metabolic analysis of both male and female mice consuming a Western diet of trans fats and sugar, focusing on both their hepatic phenotype and extrahepatic manifestations.

Hypothyroidism-Induced Nonalcoholic Fatty Liver Disease (HIN): Mechanisms and Emerging Therapeutic Options

Nonalcoholic fatty liver disease (NAFLD) is an emerging worldwide problem and its association with other metabolic pathologies has been one of the main research topics in the last decade. The aim of this review article is to provide an up-to-date correlation between hypothyroidism and NAFLD. We followed evidence regarding epidemiological impact, immunopathogenesis, thyroid hormone-liver axis, lipid and cholesterol metabolism, insulin resistance, oxidative stress, and inflammation. After evaluating the influence of thyroid hormone imbalance on liver structure and function, the latest studies have focused on developing new therapeutic strategies. Thyroid hormones (THs) along with their metabolites and thyroid hormone receptor β (THR-β) agonist are the main therapeutic targets. Other liver specific analogs and alternative treatments have been tested in the last few years as potential NAFLD therapy. Finally, we concluded that further research is necessary as well as the need for an extensive evaluation of thyroid function in NAFLD/NASH patients, aiming for better management and outcome.

History of Nonalcoholic Fatty Liver Disease

Based on the assumption that characterizing the history of a disease will help in improving practice while offering a clue to research, this article aims at reviewing the history of nonalcoholic fatty liver disease (NAFLD) in adults and children. To this end, we address the history of NAFLD histopathology, which begins in 1980 with Ludwig's seminal studies, although previous studies date back to the 19th century. Moreover, the principal milestones in the definition of genetic NAFLD are summarized. Next, a specific account is given of the evolution, over time, of our understanding of the association of NAFLD with metabolic syndrome, spanning from the outdated concept of "NAFLD as a manifestation of the Metabolic Syndrome", to the more appropriate consideration that NAFLD has, with metabolic syndrome, a mutual and bi-directional relationship. In addition, we also report on the evolution from first intuitions to more recent studies, supporting NAFLD as an independent risk factor for cardiovascular disease. This association probably has deep roots, going back to ancient Middle Eastern cultures, wherein the liver had a significance similar to that which the heart holds in contemporary society. Conversely, the notions that NAFLD is a forerunner of hepatocellular carcinoma and extra-hepatic cancers is definitely more modern. Interestingly, guidelines issued by hepatological societies have lagged behind the identification of NAFLD by decades. A comparative analysis of these documents defines both shared attitudes (e.g., ultrasonography and lifestyle changes as the first approaches) and diverging key points (e.g., the threshold of alcohol consumption, screening methods, optimal non-invasive assessment of liver fibrosis and drug treatment options). Finally, the principal historical steps in the general, cellular and molecular pathogenesis of NAFLD are reviewed. We conclude that an in-depth understanding of the history of the disease permits us to better comprehend the disease itself, as well as to anticipate the lines of development of future NAFLD research.

Oxidative Stress and Pro-Inflammatory Status in Patients with Non-Alcoholic Fatty Liver Disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is characterized by excessive fat accumulation, especially triglycerides, in hepatocytes. If the pathology is not properly treated, it can progress to nonalcoholic steatohepatitis (NASH) and continue to fibrosis, cirrhosis or hepatocarcinoma.

OBJECTIVE

The aim of the current research was to identify the plasma biomarkers of liver damage, oxidative stress and inflammation that facilitate the early diagnosis of the disease and control its progression.

METHODS

Antioxidant and inflammatory biomarkers were measured in the plasma of patients diagnosed with NAFLD (n = 100 adults; 40-60 years old) living in the Balearic Islands, Spain. Patients were classified according to the intrahepatic fat content (IFC) measured by magnetic resonance imaging (MRI).

RESULTS

Circulating glucose, glycosylated haemoglobin, triglycerides, low-density lipoprotein-cholesterol, aspartate aminotransferase and alanine aminotransferase were higher in patients with an IFC ≥ 2 of NAFLD in comparison to patients with an IFC of 0 and 1. The plasma levels of catalase, irisin, interleukin-6, malondialdehyde, and cytokeratin 18 were higher in stage ≥2 subjects, whereas the resolvin D1 levels were lower. No differences were observed in xanthine oxidase, myeloperoxidase, protein carbonyl and fibroblast growth factor 21 depending on liver status.

CONCLUSION

The current available data show that the severity of NAFLD is associated with an increase in oxidative stress and proinflammatory status. It may be also useful as diagnostic purpose in clinical practice.

Perspectives of nonalcoholic fatty liver disease research: a personal point of view

Rational government of patient fluxes from primary care to hepatology clinic is a priority of nonalcoholic fatty liver disease (NAFLD) research. Estimating pre-test probability of disease, risk of fibrosis progression, and exclusion of competing causes of liver disease must be addressed. Here we propose a novel taxonomic classification of NAFLD based on hepatic, pathogenic and systemic features of disease in the individual patient. The variable course of disease in any given patient remains a clinical enigma. Therefore, future studies will have to better characterize the role of genetic polymorphisms, family and personal history, diet, alcohol, physical activity and drugs as modifiers of the course of disease and clues to the early diagnosis of hepatocellular carcinoma. A better understanding of these, together with a taxonomic diagnosis, may prompt a more accurate personalization of care. For example, understanding the putative role of psycho-depression in NAFLD promises to revolutionize disease management in a proportion of cases. Similarly, sex differences in outcome and response to treatment are insufficiently characterized. More studies are awaited regarding those forms of NAFLD which occur secondary to endocrine derangements. The intersections between NAFLD and the lung must better be defined. These include the bi-directional associations of NAFLD and chronic obstructive pulmonary disease and sleep apnoea syndrome, as well as the totally unexplored chapter of NAFLD and coronavirus disease 2019 (COVID-19). Finally, the therapeutic roles of intermittent fasting and anticoagulation must be assessed. In conclusion, over the last 20 years, NAFLD has taught us a lot regarding the pathogenic importance of insulin resistance, the limitations of correcting this in the treatment of NAFLD, the root causes of diabetes and the metabolic syndrome, sex differences in disease and the role of nuclear receptors. However, the overwhelming COVID-19 pandemic is now expected to reset the priorities of public health.

Perspectives of nonalcoholic fatty liver disease research: a personal point of view

Rational government of patient fluxes from primary care to hepatology clinic is a priority of nonalcoholic fatty liver disease (NAFLD) research. Estimating pre-test probability of disease, risk of fibrosis progression, and exclusion of competing causes of liver disease must be addressed. Here we propose a novel taxonomic classification of NAFLD based on hepatic, pathogenic and systemic features of disease in the individual patient. The variable course of disease in any given patient remains a clinical enigma. Therefore, future studies will have to better characterize the role of genetic polymorphisms, family and personal history, diet, alcohol, physical activity and drugs as modifiers of the course of disease and clues to the early diagnosis of hepatocellular carcinoma. A better understanding of these, together with a taxonomic diagnosis, may prompt a more accurate personalization of care. For example, understanding the putative role of psycho-depression in NAFLD promises to revolutionize disease management in a proportion of cases. Similarly, sex differences in outcome and response to treatment are insufficiently characterized. More studies are awaited regarding those forms of NAFLD which occur secondary to endocrine derangements. The intersections between NAFLD and the lung must better be defined. These include the bi-directional associations of NAFLD and chronic obstructive pulmonary disease and sleep apnoea syndrome, as well as the totally unexplored chapter of NAFLD and coronavirus disease 2019 (COVID-19). Finally, the therapeutic roles of intermittent fasting and anticoagulation must be assessed. In conclusion, over the last 20 years, NAFLD has taught us a lot regarding the pathogenic importance of insulin resistance, the limitations of correcting this in the treatment of NAFLD, the root causes of diabetes and the metabolic syndrome, sex differences in disease and the role of nuclear receptors. However, the overwhelming COVID-19 pandemic is now expected to reset the priorities of public health.

Direct Oral Anticoagulants in Patients with Liver Disease in the Era of Non-Alcoholic Fatty Liver Disease Global Epidemic: A Narrative Review

Atrial fibrillation (AF) and venous thromboembolism (VTE) are highly prevalent and relevant healthcare issues. Direct oral anticoagulants (DOACs) are now the first-choice for anticoagulant treatment of these conditions displaying a better efficacy/safety profile than vitamin-K antagonists, mainly due to significantly reduced risk of major bleeding, especially of intracranial haemorrhage. Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in developed countries showing a continuously growing prevalence. Nonalcoholic steatohepatitis (NASH), its evolutive form, will be the leading cause for liver transplantation by 2020. NAFLD is independently associated with an increased risk of abnormalities of cardiac structure and function, including cardiac rhythm disorders (mainly AF). Moreover, data suggest an increased risk of unprovoked VTE associated with NAFLD/NASH. Therefore, a growing number of patients with chronic liver disease (CLD) will be candidate for anticoagulant therapy in the near future. Cirrhosis of any etiology is characterized by an unstable thrombosis/bleeding haemostatic balance, making anticoagulant therapy particularly challenging in this condition. Given that patients with significant active liver disease and cirrhosis were excluded from all pivotal randomized controlled trials on DOACs, this comprehensive review aims at critically discussing real-world evidence, including the latest population studies, regarding the use of DOACs in patients with CLD/cirrhosis.

Sexual Dimorphism of NAFLD in Adults. Focus on Clinical Aspects and Implications for Practice and Translational Research

Nonalcoholic fatty liver disease (NAFLD) embraces the clinico-pathological consequences of hepatic lipotoxicity and is a major public health problem globally. Sexual dimorphism is a definite feature of most human diseases but, under this aspect, NAFLD lags behind other medical fields. Here, we aim at summarizing and critically discussing the most prominent sex differences and gaps in NAFLD in humans, with emphasis on those aspects which are relevant for clinical practice and translational research. Sexual dimorphism of NAFLD is covered with references to the following areas: disease prevalence and risk factors, pathophysiology, comorbidities, natural course and complications. Finally, we also discuss selected gender differences and whether sex-specific lifestyle changes should be adopted to contrast NAFLD in men and women.