Fatty liver incidence and predictive variables

Assessment of the Liver Steatosis and Fibrosis Risk in Metabolic Syndrome and Its Individual Components, Considering the Varying Definitions Used in Clinical Practice throughout Time: A Retrospective Cross-Sectional Study

Multiple modifications of metabolic syndrome diagnostic criteria have been made-NCEP: ATP III (from 2001, modified in 2004), IDF (2005), IDF Consortium (2009), or Polish Scientific Society Consortium standards (2022) are now frequently in use. Hepatosteatosis and hepatofibrosis are commonly mentioned aspects of metabolic syndrome that greatly increase the likelihood of developing complications. The objective of the study was to assess different diagnostic criteria for metabolic syndrome based on the prevalence of liver steatosis and fibrosis. A retrospective analysis was conducted on the medical data of 2102 patients. Out of all the single criteria, meeting the obesity criterion based on waist circumference showed the highest increase in the risk of hepatosteatosis (by 64-69%, depending on the definition used)-hypertriglyceridemia increased the risk of hepatofibrosis by 71%. Regardless of the specific criteria used, patients with metabolic syndrome had a 34-36% increased likelihood of developing hepatosteatosis-the probability of hepatofibrosis varied between 42% and 47% for the criteria established in 2004, 2005, and 2009, while the Polish 2022 criteria were not statistically significant (p = 0.818). It seems appropriate to establish consistent metabolic syndrome diagnostic criteria-the 2009 IDF guidelines are the most effective in assessing hepatosteatosis and fibrosis risk.

Non-Pharmacological Approach to Diet and Exercise in Metabolic-Associated Fatty Liver Disease: Bridging the Gap between Research and Clinical Practice

This review provides a practical and comprehensive overview of non-pharmacological interventions for metabolic-associated fatty liver disease (MASLD), focusing on dietary and exercise strategies. It highlights the effectiveness of coffee consumption, intermittent fasting, and Mediterranean and ketogenic diets in improving metabolic and liver health. The review emphasizes the importance of combining aerobic and resistance training as a critical approach to reducing liver fat and increasing insulin sensitivity. Additionally, it discusses the synergy between diet and exercise in enhancing liver parameters and the role of gut microbiota in MASLD. The paper underscores the need for a holistic, individualized approach, integrating diet, exercise, gut health, and patient motivation. It also highlights the long-term benefits and minimal risks of lifestyle interventions compared to the side effects of pharmacological and surgical options. The review calls for personalized treatment strategies, continuous patient education, and further research to optimize therapeutic outcomes in MASLD management.

Association between dietary inflammation index and hypertension in participants with different degrees of liver steatosis

BACKGROUND

The prevalence of hypertension (HTN) is higher in patients with non-alcoholic fatty liver disease (NAFLD). Inflammation is the key link between HTN and NAFLD. Systemic inflammation can be dramatically increased by inflammatory diet intake. However, whether controlling the inflammatory diet intake in NAFLD patients could affect the occurrence of HTN still remains unknown. Our aim here is to evaluate the effect of the dietary inflammatory index (DII) on blood pressure in patients with different grades of hepatic steatosis.

MATERIALS AND METHODS

The data were collected from the National Health and Nutrition Examination Survey (NHANES) (2017-2018). DII was calculated based on the data of 24-h dietary recall interviews. The severity of liver steatosis was assessed by a controlled attenuation parameter. Multivariable logistic regression, multivariable linear regression and subgroup analyses were conducted to determine the association between DII and blood pressure in patients with different degrees of hepatic steatosis.

RESULTS

A total of 5449 participants were included in this analysis. In male participants with severe liver steatosis (S3), the highest DII tertile group was more likely to have higher systolic blood pressure (SBP) compared with the lowest tertile group (Tertile1: 128.31(125.31,131.31), Tertile3: 133.12(129.40,136.85), P for trend =0.03551). DII was positively correlated with SBP and the prevalence of HTN in males with hepatic steatosis grade S3 (≥ 67% steatosis) (SBP: P for trend = 0.011, HTN: P for trend = 0.039). Regarding the association of DII with SBP and HTN, the tests for interaction were significant for hepatic steatosis (SBP: interaction for p = 0.0015, HTN: interaction for p = 0.0202).

CONCLUSIONS

In the present study, we demonstrated that DII was a risk factor for increased SBP and the prevalence of HTN in males with severe hepatic steatosis S3, indicating that anti-inflammatory dietary management should be considered in these individuals to reduce the risk of developing HTN.

Overview of hepatocellular carcinoma: from molecular aspects to future therapeutic options

Hepatocellular carcinoma (HCC) is the seventh most highly prevalent malignant tumor globally and the second most common cause of mortality. HCC develops with complex pathways that occur through multistage biological processes. Non-alcoholic fatty liver disease, metabolic-associated fatty liver disease, alcoholic liver disease, autoimmune hepatitis, hepatitis B, and hepatitis C are the causative etiologies of HCC. HCC develops as a result of epigenetic changes, protein-coding gene mutations, and altered signaling pathways. Biomarkers and potential therapeutic targets for HCC open up new possibilities for treating the disease. Immune checkpoint inhibitors are included in the treatment options in combination with molecular targeted therapy.

The role of TRIM family in metabolic associated fatty liver disease

Metabolic associated fatty liver disease (MAFLD) ranks among the most prevalent chronic liver conditions globally. At present, the mechanism of MAFLD has not been fully elucidated. Tripartite motif (TRIM) protein is a kind of protein with E3 ubiquitin ligase activity, which participates in highly diversified cell activities and processes. It not only plays an important role in innate immunity, but also participates in liver steatosis, insulin resistance and other processes. In this review, we focused on the role of TRIM family in metabolic associated fatty liver disease. We also introduced the structure and functions of TRIM proteins. We summarized the TRIM family's regulation involved in the occurrence and development of metabolic associated fatty liver disease, as well as insulin resistance. We deeply discussed the potential of TRIM proteins as targets for the treatment of metabolic associated fatty liver disease.

Puberty as a DOHaD programming window: high-fat diet induces long-term hepatic dysfunction in male rats

The aim of this study was to evaluate whether high-fat (HF) diet intake during puberty can program obesity as well as generate glucose imbalance and hepatic metabolic dysfunctions in adult life. Male Wistar rats were randomly assigned into two groups: rats fed standard chow (NF) and rats fed a HF from postnatal 30-day-old (PND30) until PND60. Then, both groups were fed a standard chow from PND60 until PND120. Euthanasia and samples collections occurred at PND120. HF animals were overweight (+11%) and had increased adiposity, hyperphagia (+12%), hyperglycaemia (+13%), hyperinsulinemia (+69%), and hypertriglyceridemia (+34%). Plasma glucose levels during intravenous glucose tolerance test (ivGTT) and intraperitoneal insulin tolerance test (ipITT) were also higher in the HF group, whereas Kitt was significantly lower (-34%), suggesting reduced insulin sensitivity. In the same sense, HF animals present pancreatic islets hypertrophy and high β-cell mass. HF animals also had a significant increase in blood glucose levels during pyruvate tolerance test, indicating increased gluconeogenesis. Hepatic morphology analyses showed an increase in lipid inclusion in the HF group. Moreover, PEPCK and FAS protein expression were higher in the livers of the HF animals (+79% and + 37%, respectively). In conclusion, HF during puberty causes obese phenotype leading to glucose dyshomeostasis and nonalcoholic fatty liver disease, which can be related to the overexpression of proteins PEPCK and FAS.

Which Comes First, Nonalcoholic Fatty Liver Disease or Arterial Hypertension?

Non-alcoholic fatty liver disease (NAFLD) and arterial hypertension (AH) are widespread noncommunicable diseases in the global population. Since hypertension and NAFLD are diseases associated with metabolic syndrome, they are often comorbid. In fact, many contemporary published studies confirm the association of these diseases with each other, regardless of whether other metabolic factors, such as obesity, dyslipidemia, and type 2 diabetes mellites, are present. This narrative review considers the features of the association between NAFLD and AH, as well as possible pathophysiological mechanisms.

Analysis of factors affecting nonalcoholic fatty liver disease in Chinese steel workers and risk assessment studies

BACKGROUND

The global incidence of nonalcoholic fatty liver disease (NAFLD) is rapidly escalating, positioning it as a principal public health challenge with significant implications for population well-being. Given its status as a cornerstone of China's economic structure, the steel industry employs a substantial workforce, consequently bringing associated health issues under increasing scrutiny. Establishing a risk assessment model for NAFLD within steelworkers aids in disease risk stratification among this demographic, thereby facilitating early intervention measures to protect the health of this significant populace.

METHODS

Use of cross-sectional studies. A total of 3328 steelworkers who underwent occupational health evaluations between January and September 2017 were included in this study. Hepatic steatosis was uniformly diagnosed via abdominal ultrasound. Influential factors were pinpointed using chi-square (χ2) tests and unconditional logistic regression analysis, with model inclusion variables identified by pertinent literature. Assessment models encompassing logistic regression, random forest, and XGBoost were constructed, and their effectiveness was juxtaposed in terms of accuracy, area under the curve (AUC), and F1 score. Subsequently, a scoring system for NAFLD risk was established, premised on the optimal model.

RESULTS

The findings indicated that sex, overweight, obesity, hyperuricemia, dyslipidemia, occupational dust exposure, and ALT serve as risk factors for NAFLD in steelworkers, with corresponding odds ratios (OR, 95% confidence interval (CI)) of 0.672 (0.487-0.928), 4.971 (3.981-6.207), 16.887 (12.99-21.953), 2.124 (1.77-2.548), 2.315 (1.63-3.288), 1.254 (1.014-1.551), and 3.629 (2.705-4.869), respectively. The sensitivity of the three models was reported as 0.607, 0.680 and 0.564, respectively, while the precision was 0.708, 0.643, and 0.701, respectively. The AUC measurements were 0.839, 0.839, and 0.832, and the Brier scores were 0.150, 0.153, and 0.155, respectively. The F1 score results were 0.654, 0.661, and 0.625, with log loss measures at 0.460, 0.661, and 0.564, respectively. R2 values were reported as 0.789, 0.771, and 0.778, respectively. Performance was comparable across all three models, with no significant differences observed. The NAFLD risk score system exhibited exceptional risk detection capabilities with an established cutoff value of 86.

CONCLUSIONS

The study identified sex, BMI, dyslipidemia, hyperuricemia, occupational dust exposure, and ALT as significant risk factors for NAFLD among steelworkers. The traditional logistic regression model proved equally effective as the random forest and XGBoost models in assessing NAFLD risk. The optimal cutoff value for risk assessment was determined to be 86. This study provides clinicians with a visually accessible risk stratification approach to gauge the propensity for NAFLD in steelworkers, thereby aiding early identification and intervention among those at risk.

Association Between Hypertension and New-Onset Non-Alcoholic Fatty Liver Disease in Chinese Non-Obese People: A Longitudinal Cohort Study

BACKGROUND

Quantification of the relationship between hypertension and non-alcoholic fatty liver disease (NAFLD) risk is limited and controversial. This study aimed to investigate the relationship between hypertension and NAFLD in non-obese Chinese and to use different methods to demonstrate that hypertension is an independent risk factor for NAFLD.

METHODS

On 16,153 nonobese individuals, a retrospective cohort study was conducted in China to examine the impact of hypertension on incident NAFLD. We compared five methods: multivariable Cox proportional-hazards regression, propensity score-matched (PSM) analysis, propensity score adjustment method (considering the propensity score as a covariate in a multivariable Cox proportional-hazard regression), and two propensity score-based weighted methods-The first one estimated the hypertension effect in the overall study population-inverse probability of treatment weights (IPTW), the other in the hypertensive population-standardized mortality ratio (SMR) weights. We also used a genetic matching (GenMatch) algorithm to match the participants for sensitive analysis.

RESULTS

Between 2010 and 2014, 16,153 participants met our inclusion criteria, including 2427 (15.03%) with hypertension. A total of 2321 (14.37%) participants developed NAFLD during the median follow-up of 2.98 years. The crude hazard ratio (HR) between hypertension and incident NAFLD was 2.05 (95% confidence interval (CI): 1.87, 2.25). The adjusted HR depended on the different methods, ranging from 1.09 (95% CI: 0.77, 1.23) for the PSM method to 2.24 (95% CI: 2.05, 2.44) for the SMR weighted analysis. Hypertensive participants with high propensity scores had a higher risk of developing NAFLD in the future. Excluding participants with propensity scores <8% yielded comparable hazard ratios with a narrower range, from 1.04 to 1.80. After adjusting for the confounding variables, the relationship also existed in the GenMatch cohort as a sensitivity analysis (HR=1.06, 95% CI 1.01-1.13).

CONCLUSION

Hypertension is a significant cause of NAFLD in Chinese adults in non-obese Chinese adults, with the hazard ratio ranging from 1.09 to 2.24.

Subclinical and clinical atherosclerosis in non-alcoholic fatty liver disease is associated with the presence of hypertension

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) is associated with increased cardiovascular (CV) risk. However, it is unclear whether NAFLD contributes independently to the development of CV disease. Our study aimed at assessing the differences in several indices of atherosclerosis, arterial stiffness and cardiac morphology among patients with isolated NAFLD, isolated hypertension (HT) or a combination of the two conditions.

METHODS AND RESULTS

A total of 169 participants (mean age = 50.4 ± 10.2 yrs; males = 73.6%) were divided according to the presence of NAFLD and HT into three groups: only NAFLD (55 patients), only HT (49 patients), and NAFLD + HT (65 patients). Exclusion criteria were a BMI≥35 kg/m² and a diagnosis of diabetes mellitus. Carotid ultrasonography was performed to measure markers of atherosclerosis and arterial stiffness. Cardiac remodeling was analyzed using echocardiography. The prevalence of subclinical and overt atherosclerosis was significantly higher in the NAFLD + HT patients as compared to the other two groups (atherosclerotic plaques: 43.1%, 10.9%, and 22.4% (p < 0.001) in NAFLD + HT, NAFLD, and HT groups, respectively). No differences were found among indices of arterial stiffening and cardiac remodeling across the three groups. In multivariate regression analysis, the coexistence of NAFLD and HT was an independent risk factor for overt atherosclerosis (OR = 4.88, CI 95% 1.14-20.93), while no association was found when either NAFLD or HT was considered alone.

CONCLUSION

Overt atherosclerosis was significantly present only in NAFLD + HT patients, but not in patients with isolated NAFLD. This implies that the impact of NAFLD on vascular structure and function could depend on the coexistence of other major CV risk factors, such as HT.

Comprehensive Review of Cardiovascular Disease Risk in Nonalcoholic Fatty Liver Disease

Nonalcoholic Fatty Liver Disease (NAFLD) is a growing global phenomenon, and its damaging effects in terms of cardiovascular disease (CVD) risk are becoming more apparent. NAFLD is estimated to affect around one quarter of the world population and is often comorbid with other metabolic disorders including diabetes mellitus, hypertension, coronary artery disease, and metabolic syndrome. In this review, we examine the current evidence describing the many ways that NAFLD itself increases CVD risk. We also discuss the emerging and complex biochemical relationship between NAFLD and its common comorbid conditions, and how they coalesce to increase CVD risk. With NAFLD's rising prevalence and deleterious effects on the cardiovascular system, a complete understanding of the disease must be undertaken, as well as effective strategies to prevent and treat its common comorbid conditions.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the past years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato, the Società Italiana di Diabetologia and the Società Italiana dell'Obesità reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure and Istituto Superiore di Sanità. Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources.Level of evidence Level of evidence of recommendations for each PICO question were reported according to available evidence.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes, and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the last years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato (AISF), the Società Italiana di Diabetologia (SID) and the Società Italiana dell'Obesità (SIO) reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure (CNEC) and Istituto Superiore di Sanità (ISS). Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources. Level of evidence: Level of evidence of recommendations for each PICO question were reported according to available evidence.

Non-alcoholic fatty liver disease in adults 2021: A clinical practice guideline of the Italian Association for the Study of the Liver (AISF), the Italian Society of Diabetology (SID) and the Italian Society of Obesity (SIO)

Nonalcoholic fatty liver disease (NAFLD) is a common and emerging liver disease in adults, paralleling the epidemic of obesity and diabetes, and leading to worrisome events (hepatocellular carcinoma and end-stage liver disease). In the last years, mounting evidence added insights about epidemiology, natural history, diagnosis and lifestyle-based or drug treatment of NAFLD. In this rapidly evolving scenario, members of the Associazione Italiana per lo Studio del Fegato (AISF), the Società Italiana di Diabetologia (SID) and the Società Italiana dell'Obesità (SIO) reviewed current knowledge on NAFLD. The quality of the published evidence is graded, and practical recommendations are made following the rules and the methodology suggested in Italy by the Centro Nazionale per l'Eccellenza delle cure (CNEC) and Istituto Superiore di Sanità (ISS). Whenever possible, recommendations are placed within the context the Italian Healthcare system, with reference to specific experience and local diagnostic and management resources. Level of evidence: Level of evidence of recommendations for each PICO question were reported according to available evidence.

Bidirectional Association between Hypertension and NAFLD: A Systematic Review and Meta-Analysis of Observational Studies

An increasing body of evidence connects non-alcoholic fatty liver disease (NAFLD) to hypertension. The objective of this systematic review and meta-analysis was to estimate the nature and magnitude of the association between NAFLD and hypertension. We systematically searched PubMed, Embase, Cochrane Library, and Web of Science for observational studies published up to May 1, 2021. Cohort studies that reported data on the association between NAFLD and incident hypertension or between hypertension and incident NAFLD were included. We used random-effects models to conduct meta-analysis on the measures of association from individual studies. A total of 11 studies were eligible for inclusion, among which 4 studies including 25,260 participants reported the association between hypertension and new-onset NAFLD. The presence of hypertension was significantly associated with an increased risk of incident NAFLD (HR 1.63, 95% CI: 1.41-1.88; I ² = 37.6%). On the other hand, 9 studies with data on 46,487 participants analyzed the effects of NAFLD on incident hypertension. Pooled analysis showed that the presence of NAFLD was significantly associated with an increased incidence of hypertension (HR 1.55, 95% CI: 1.29-1.87; I ² = 80.5%). There was significant heterogeneity among the studies in this analysis (p < 0.01). Sensitivity analyses showed that the magnitude of the association was significantly different in subgroups stratified by a mean age of participants and geographical location, which explains part of the heterogeneity. In conclusion, this meta-analysis indicates the existence of a bidirectional relationship between NAFLD and hypertension independent of traditional cardiometabolic risk factors.

Nuciferine, an active ingredient derived from lotus leaf, lights up the way for the potential treatment of obesity and obesity-related diseases

Obesity, is an increasingly global public health problem associated complications. However, the proven anti-obesity agents are inefficient with adverse side effects; hence attention is being paid to novel drugs from natural resources to manage obesity and obesity-related diseases. Nuciferine (NF) is a high-quality aporphine alkaloid present in lotus leaf. Unlike the chemical drugs, NF elicits anti-obesity, anti-dyslipidemia, anti-hyperglycemic, anti-hypouricemic, anti-inflammatory, and anti-tumor effects, and affinity to neural receptors, and protection against obesity-related diseases. The underlying mechanism of NF includes the regulation of targeted molecules and pathways related to metabolism, inflammation, and cancer and modulation of Ca²⁺ flux, gut microbiota, and ferroptosis. Besides, the clinical application, availability, pharmacokinetics, pharmaceutics, and security of NF have been established, highlighting the potential of developing NF as an anti-obesity agent. Therefore, this review provides a comprehensive summarization, which sheds light on future research in NF.

NAFLD-Related Hepatocarcinoma: The Malignant Side of Metabolic Syndrome

Hepatocellular carcinoma (HCC) is the seventh most common cancer worldwide and the second leading cause of cancer-related mortality. HCC typically arises within a cirrhotic liver, but in about 20% of cases occurs in absence of cirrhosis. Among non-cirrhotic risk factors, non-alcoholic fatty liver disease (NAFLD) currently represents the most important emerging cause of HCC in developed countries. It has been estimated that annual incidence of HCC among patients with non-cirrhotic NAFLD is approximately 0.1-1.3 per 1000 patients/year and ranges from 0.5% to 2.6% among patients with non-alcoholic steatohepatitis (NASH) cirrhosis. However, only a few clinical trials enrolling HCC patients actually distinguished NAFLD/NASH-related cases from other non-cirrhotic causes and therefore evidence is still lacking in this subset of patients. This review aims to describe the biology underpinning NAFLD development, to investigate the main molecular pathways involved in its progression to NASH and HCC and to describe how different pathogenetic mechanisms underlying the onset of HCC can have an impact in clinical practice. We hereby also provide an overview of current HCC treatment options, with a particular focus on the available data on NAFLD-related cases in practice-changing clinical trials.

Bi-directional and temporal relationship between elevated alanine aminotransferase and hypertension in a longitudinal study of Chinese adults

OBJECTIVE

Despite the strong correlation between elevated alanine aminotransferase (ALT) and hypertension, their bi-directional and temporal relationship are currently unclear. Our study aimed to explore the bi-directional and temporal association between elevated ALT (ALT > 40 U/L) and hypertension.

METHODS

Measurements of alanine aminotransferase and blood pressure were obtained twice from 2013 to 2017 in 3314 Chinese adults without cardiovascular disease at baseline. Bi-directional and cross-lagged panel analyses were performed to dissect the temporal relationship between elevated ALT and hypertension.

RESULTS

Longitudinally, we found that baseline elevated ALT was strongly correlated with incident hypertension (odds ratios = 2.16, P = .001), and baseline hypertension was also significantly associated with incident elevated ALT (odds ratios = 1.64, P = .026). The cross-lagged path coefficients from baseline ALT to follow-up blood pressure were significantly greater than that from baseline blood pressure to follow-up ALT (β: 0.043 vs. 0.026, P < .05 for systolic blood pressure and β: 0.052 vs. 0.024, P < .05 for diastolic blood pressure).

CONCLUSION

Our results provide evidence for the bi-directional association of elevated ALT and hypertension among Chinese adults, and elevated ALT probably antedates the development of hypertension.

Clinical impact of sexual dimorphism in non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH)

NAFLD/NASH is a sex-dimorphic disease, with a general higher prevalence in men. Women are at reduced risk of NAFLD compared to men in fertile age, whereas after menopause women have a comparable prevalence of NAFLD as men. Indeed, sexual category, sex hormones and gender habits interact with numerous NAFLD factors including cytokines, stress and environmental factors and alter the risk profiles and phenotypes of NAFLD. In the present review, we summarized the last findings about the influence of sex on epidemiology, pathogenesis, progression in cirrhosis, indication for liver transplantation and alternative therapies, including lifestyle modification and pharmacological strategies. We are confident that an appropriate consideration of sex, age, hormonal status and sociocultural gender differences will lead to a better understanding of sex differences in NAFLD risk, therapeutic targets and treatment responses and will aid in achieving sex-specific personalized therapies.

Nonalcoholic Fatty Liver Disease and Cardiovascular Disease: Overlapping Mechanisms

Nonalcoholic fatty liver disease (NAFLD) denotes a condition with excess fat in the liver. The prevalence of NAFLD is increasing, averaging > 25% of the Western population. In 25% of the patients, NAFLD progresses to its more severe form: nonalcoholic steatohepatitis and >25% of these progress to cirrhosis following activation of inflammatory and fibrotic processes. NAFLD is associated with obesity, type 2 diabetes, and the metabolic syndrome and represents a considerable and increasing health burden. In the near future, NAFLD cirrhosis is expected to be the most common cause for liver transplantation. NAFLD patients have an increased risk of developing cardiovascular disease as well as liver-related morbidity. In addition, hepatic steatosis itself appears to represent an independent cardiovascular risk factor. In the present review, we provide an overview of the overlapping mechanisms and prevalence of NAFLD and cardiovascular disease.

In Utero Exposure to Δ9-Tetrahydrocannabinol Leads to Postnatal Catch-Up Growth and Dysmetabolism in the Adult Rat Liver

The rates of gestational cannabis use have increased despite limited evidence for its safety in fetal life. Recent animal studies demonstrate that prenatal exposure to Δ9-tetrahydrocannabinol (Δ9-THC, the psychoactive component of cannabis) promotes intrauterine growth restriction (IUGR), culminating in postnatal metabolic deficits. Given IUGR is associated with impaired hepatic function, we hypothesized that Δ9-THC offspring would exhibit hepatic dyslipidemia. Pregnant Wistar rat dams received daily injections of vehicular control or 3 mg/kg Δ9-THC i.p. from embryonic day (E) 6.5 through E22. Exposure to Δ9-THC decreased the liver to body weight ratio at birth, followed by catch-up growth by three weeks of age. At six months, Δ9-THC-exposed male offspring exhibited increased visceral adiposity and higher hepatic triglycerides. This was instigated by augmented expression of enzymes involved in triglyceride synthesis (ACCα, SCD, FABP1, and DGAT2) at three weeks. Furthermore, the expression of hepatic DGAT1/DGAT2 was sustained at six months, concomitant with mitochondrial dysfunction (i.e., elevated p66shc) and oxidative stress. Interestingly, decreases in miR-203a-3p and miR-29a/b/c, both implicated in dyslipidemia, were also observed in these Δ9-THC-exposed offspring. Collectively, these findings indicate that prenatal Δ9-THC exposure results in long-term dyslipidemia associated with enhanced hepatic lipogenesis. This is attributed by mitochondrial dysfunction and epigenetic mechanisms.

The association between hypertension and nonalcoholic fatty liver disease (NAFLD): literature evidence and systems biology analysis

Nonalcoholic fatty liver disease (NAFLD) has become a major public health issue as its progression increases risks of multisystem morbidity and mortality. Recent evidence indicates a more complex relationship between hypertension and NAFLD than previously thought. In this study, a comprehensive literature search was used to gather information supporting the comorbidity phenomenon of hypertension and NAFLD. Then, systems biology approach was applied to identify the potential genes and mechanisms simultaneously associated with hypertension and NAFLD. With the help of protein-protein interaction network-based algorithm, we found that the distance between hypertension and NAFLD was much less than random ones. Sixty-four shared genes of hypertension and NAFLD modules were identified as core genes. Kyoto Encyclopedia of Genes and Genomes(KEGG) enrichment analysis indicated that some inflammatory, metabolic and endocrine signals were related to the potential biological functions of core genes. More importantly, drugs used to treat cardiovascular diseases, hypertension, hyperlipidemia, inflammatory diseases and depression could be potential therapeutics against hypertension-NAFLD co-occurrence. After analyzing public OMICs data, ALDH1A1 was identified as a potential therapeutic target, without being affected by reverse causality. These findings give a clue for the potential mechanisms of comorbidity of hypertension and NAFLD and highlight the multiple target-therapeutic strategy of NAFLD for future clinical research.

Fatty Liver, and Not Visceral Fat, Is More Associated with Liver Fibrosis and Diabetes in Non-Obese Japanese Individuals: A Cross-Sectional Study

Asians are known to be more likely than Westerners to develop fatty liver and lifestyle-related diseases in spite of their weight. However, the relationship between fat accumulation and lifestyle-related diseases in non-obese Asians is unknown. Therefore, this study aimed to analyze visceral fat and hepatic fat in participants with a normal body mass index (BMI) and examine their characteristics during a medical checkup. This cross-sectional study was conducted on 663 of 1142 patients who underwent abdominal ultrasonography and who had an alcohol intake (converted to ethanol) of <30 g/day for males and <20 g/day for females and a BMI of <25 kg/m² during a health checkup. Participants were classified into four groups: group A, visceral fat accumulation (VFA) (−) and fatty liver (FL) (−) (n = 549); group B, VFA (+) and FL (−) (n = 32); group C, VFA (−) and FL (+) (n = 58); and group D, VFA (+) and FL (+) (n = 24). The frequencies of lifestyle-related disease complications, liver function tests, and liver fibrosis were evaluated among the four groups. Compared with group A (control), groups B, C, and D had a higher number of males, BMI, abdominal circumference, ALT, AST, γ-GTP, triglyceride, uric acid, fasting blood sugar levels, and incidence of hyperlipidemia. Groups C and D had higher ALT, HbA1c, cholinesterase, and triglyceride levels, FIB4 index, and the number of patients with diabetes mellitus (DM) than groups A and B; however, there was no difference between groups A and B. FL is a risk factor of DM and liver fibrosis in non-obese Japanese individuals; however, VFA only is not a risk factor of DM and liver fibrosis.

The long-term protective effects of neonatal administration of curcumin against nonalcoholic steatohepatitis in high-fructose-fed adolescent rats

There is an increased prevalence of nonalcoholic steatohepatitis (NASH) in adolescents. The suckling period is developmentally plastic, affecting later health outcomes. We investigated whether neonatal administration of curcumin would provide protection against the development of NASH later in adolescence in rats fed a high-fructose diet. From postnatal day (PN) 6 to PN 21, the pups (N = 128) were allocated to four groups and orally gavaged daily with either 0.5% dimethyl sulfoxide solution (vehicle control), curcumin (500 mg·kg^-1 ), fructose (20%, w/v) or curcumin and fructose combined. All the pups were weaned and half the rats in each group had tap water, whereas the other received fructose (20%) as their drinking fluid ad libitum for 6 weeks. The rats' liver NASH scores, lipid content, and RNA gene expression ratios of AMPKα and TNFα were determined. Hepatic lipid content was similar across the treatment groups in the males (P > 0.05, ANOVA). In the females, the hepatic lipid content in the treatment groups ranged from 2.7 to 4.3%. The livers of male and female rats that had fructose either as neonates and/or postweaning had significantly marked inflammation (P = 0.0112, Kruskal-Wallis) and fibrosis (P < 0.0001, ANOVA) which were attenuated by curcumin. The hepatic gene expression ratios for AMPKα in both sexes were significantly downregulated (P < 0.0001, ANOVA), whereas the expression ratios of TNFα were significantly upregulated (P < 0.0001) in rats fed a high-fructose diet pre and/or postweaning compared to the other groups. Neonatal curcumin administration is a potential natural pharmacological candidate for the prevention of NASH.

Sex Hormone-Dependent Physiology and Diseases of Liver

Sexual dimorphism is associated not only with somatic and behavioral differences between men and women, but also with physiological differences reflected in organ metabolism. Genes regulated by sex hormones differ in expression in various tissues, which is especially important in the case of liver metabolism, with the liver being a target organ for sex hormones as its cells express estrogen receptors (ERs: ERα, also known as ESR1 or NR3A; ERβ; GPER (G protein-coupled ER, also known as GPR 30)) and the androgen receptor (AR) in both men and women. Differences in sex hormone levels and sex hormone-specific gene expression are mentioned as some of the main variations in causes of the incidence of hepatic diseases; for example, hepatocellular carcinoma (HCC) is more common in men, while women have an increased risk of autoimmune liver disease and show more acute liver failure symptoms in alcoholic liver disease. In non-alcoholic fatty liver disease (NAFLD), the distinction is less pronounced, but increased incidences are suggested among men and postmenopausal women, probably due to an increased tendency towards visceral fat accumulation.

17β-estradiol ameliorates lipotoxicity-induced hepatic mitochondrial oxidative stress and insulin resistance

The prevalence and severity of nonalcoholic fatty liver disease (NAFLD) is higher in men and postmenopausal women compared to premenopausal women, suggesting a protective role for ovarian hormones. Diet-induced obesity and fatty acids surplus promote mitochondrial dysfunction in liver, triggering oxidative stress and activation of c-Jun N-terminal kinase (JNK) which has been related to the development of insulin resistance and steatosis, the main hallmarks of NAFLD. Considering that estrogen, in particular 17β-estradiol (E2), have been reported to improve mitochondrial biogenesis and function in liver, our aim was to elucidate the role of E2 in preventing fatty acid-induced insulin resistance in hepatocytes through modulation of mitochondrial function, oxidative stress and JNK activation. An in vivo study was conducted in Wistar rats of both sexes (n = 7) fed control diet and high-fat diet (HFD), and in vitro studies were carried out in HepG2 cells treated with palmitate (PA) and E2 for 24 h. Our HFD-fed male rats showed a prediabetic state characterized by greater systemic and hepatic insulin resistance, as well as higher lipid content in liver, compared to females. JNK activation rose markedly in males in response to HFD feeding, in parallel with mitochondrial dysfunction and oxidative stress. Consistently, in PA-exposed HepG2 cells, E2 treatment prevented JNK activation, insulin resistance and fatty acid accumulation. Altogether, our data highlights the importance of E2 as a mitigating factor of fatty acid-insulin resistance in hepatocytes through downregulation of JNK activation, by means of mitochondrial function improvement.

[Epidemiology of non-alcoholic steatohepatitis. Extent/burden of the problem and its impact on public health]

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of liver disease, the most common cause of chronic liver function augmentation and it will be the most common indication for liver transplantation in 2020. The prevalence of NAFLD has increased over time in line with the increase of obesity and type 2 diabetes. There is a discrepancy between the studies concerning the prevalence of NAFLD because of the different diagnostic methods used (ultrasound or magnetic resonance, fibroscan, controlled attenuation parameter (CAP), histology). Because of its high prevalence the impact of NAFLD in public health is real. Therapeutic advances must be made to better understand the natural history of NAFLD and improve the management of this emerging liver disease.

Metabolic signature of obesity-associated insulin resistance and type 2 diabetes

Background

Obesity is associated with an increased risk of insulin resistance and type 2 diabetes mellitus (T2DM). However, some obese individuals maintain their insulin sensitivity and exhibit a lower risk of associated comorbidities. The underlying metabolic pathways differentiating obese insulin sensitive (OIS) and obese insulin resistant (OIR) individuals remain unclear.

Methods

In this study, 107 subjects underwent untargeted metabolomics of serum samples using the Metabolon platform. Thirty-two subjects were lean controls whilst 75 subjects were obese including 20 OIS, 41 OIR, and 14 T2DM individuals.

Results

Our results showed that phospholipid metabolites including choline, glycerophosphoethanolamine and glycerophosphorylcholine were significantly altered from OIS when compared with OIR and T2DM individuals. Furthermore, our data confirmed changes in metabolic markers of liver disease, vascular disease and T2DM, such as 3-hydroxymyristate, dimethylarginine and 1,5-anhydroglucitol, respectively.

Conclusion

This pilot data has identified phospholipid metabolites as potential novel biomarkers of obesity-associated insulin sensitivity and confirmed the association of known metabolites with increased risk of obesity-associated insulin resistance, with possible diagnostic and therapeutic applications. Further studies are warranted to confirm these associations in prospective cohorts and to investigate their functionality.

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.

A simple clinical model predicts incident hepatic steatosis in a community-based cohort: The Framingham Heart Study

BACKGROUND AND AIMS

The factors associated with incident hepatic steatosis are not definitively known. We sought to determine factors associated with incident hepatic steatosis, as measured on computed tomography, in the community.

METHODS

We studied Framingham Heart Study participants without heavy alcohol use or baseline hepatic steatosis who underwent computed tomography scans between 2002-2005 (baseline) and 2008-2011 (follow-up). We performed a stepwise logistic regression procedure to determine the predictors associated with incident hepatic steatosis.

RESULTS

We included 685 participants (mean age: 45.0 ± 6.2 years, 46.8% women). The incidence of hepatic steatosis in our sample was 17.1% over a mean 6.3 years of follow-up. Participants who developed hepatic steatosis had more adverse cardiometabolic profiles at baseline compared to those free of hepatic steatosis at follow-up. Multivariable stepwise regression analysis showed that a simple clinical model including age, sex, body mass index, alcohol consumption and triglycerides was predictive of incident hepatic steatosis (C statistic = 0.791, 95% CI: 0.748-0.834). A complex clinical model, which included visceral adipose tissue volume and liver phantom ratio added to the simple clinical model, and had improved discrimination for predicting incident hepatic steatosis (C statistic = 0.826, 95% CI: 0.786-0.866, P < .0001).

CONCLUSIONS

The combination of demographic, clinical and imaging characteristics at baseline was predictive of incident hepatic steatosis. The use of our predictive model may help identify those at increased risk for developing hepatic steatosis who may benefit from risk factor modification although further investigation is warranted.

Insights into the Role of PPARβ/δ in NAFLD

Non-alcoholic fatty liver disease (NAFLD) is a major health issue in developed countries. Although usually associated with obesity, NAFLD is also diagnosed in individuals with low body mass index (BMI) values, especially in Asia. NAFLD can progress from steatosis to non-alcoholic steatohepatitis (NASH), which is characterized by liver damage and inflammation, leading to cirrhosis and hepatocellular carcinoma (HCC). NAFLD development can be induced by lipid metabolism alterations; imbalances of pro- and anti-inflammatory molecules; and changes in various other factors, such as gut nutrient-derived signals and adipokines. Obesity-related metabolic disorders may be improved by activation of the nuclear receptor peroxisome proliferator-activated receptor (PPAR)β/δ, which is involved in metabolic processes and other functions. This review is focused on research findings related to PPARβ/δ-mediated regulation of hepatic lipid and glucose metabolism and NAFLD development. It also discusses the potential use of pharmacological PPARβ/δ activation for NAFLD treatment.

Progress and challenges in the prevention and control of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is rapidly becoming the most common liver disease worldwide. Individuals with NAFLD have a high frequency of developing progressive liver disease and metabolism-related comorbidities, which result from of a lack of awareness and poor surveillance of the disease and a paucity of approved and effective therapies. Managing the complications of NAFLD has already begun to place a tremendous burden on health-care systems. Although efforts to identify effective therapies are underway, the lack of validated preclinical NAFLD models that represent the biology and outcomes of human disease remains a major barrier. This review summarizes the characteristics and prevalence of the disease and the status of our understanding of its mechanisms and potential therapeutic targets.

Hypertension, diabetes, atherosclerosis and NASH: Cause or consequence?

Non-alcoholic fatty liver disease (NAFLD) has become one of the most common forms of chronic liver disease worldwide and its prevalence is expected to continue rising. NAFLD has traditionally been considered a consequence of metabolic syndrome (MetS). However, the link between NAFLD and MetS components, especially type 2 diabetes mellitus (T2DM), hypertension (HTN), and cardiovascular disease (CVD) is more complex than previously thought. Indeed, the adverse effects of NAFLD extend far beyond the liver, with a large body of clinical evidence now suggesting that NAFLD may precede and/or promote the development of T2DM, HTN and atherosclerosis/CVD. The risk of developing these cardiometabolic diseases parallels the underlying severity of NAFLD. Accumulating evidence suggests that the presence and severity of NAFLD is associated with an increased risk of incident T2DM and HTN. Moreover, long-term prospective studies indicate that the presence and severity of NAFLD independently predicts fatal and nonfatal CVD events. In this review, we critically discuss the rapidly expanding body of clinical evidence that supports the existence of a bi-directional relationship between NAFLD and various components of MetS, particularly T2DM and HTN, as well as the current knowledge regarding a strong association between NAFLD and CVD morbidity and mortality. Finally, we discuss the most updated putative biological mechanisms through which NAFLD may contribute to the development of HTN, T2DM and CVD.

Impact of bariatric surgery on non-alcoholic fatty liver disease

Introduction; p to 300 million people have the body mass index (BMI) greater than 30 kg/m2. Obesity is the cause of many serious diseases, such as type 2 diabetes, hypertension, and non-alcoholic fatty liver disease (NAFLD). Bariatric surgery is the only effective method of achieving weight loss in patients with morbid obesity.

OBJECTIVES

The aim of the study was to assess the impact of bariatric surgery on non-alcoholic fatty liver disease in patients operated on due to morbid obesity.

MATERIAL AND METHODS

We included 20 patients who were qualified for bariatric procedures based on BMI &gt; 40 kg/ m2 or BMI &gt; 35kg/m2 with the presence of comorbidities. The average body weight in the group was 143.85kg, with an average BMI of 49.16kg/m2. Before the procedure, we evaluated the severity of non-alcoholic fatty liver disease in each patient using the Sheriff-Saadeh ultrasound scale. We also evaluated the levels of liver enzymes. Follow-up evaluation was performed twelve months after surgery.

RESULTS

Twelve months after surgery, the average weight was 102.34 kg. The mean %WL was 33.01%, %EWL was 58.8%, and %EBMIL was 61.37%. All patients showed remission of fatty liver disease. Liver damage, evaluated with ultrasound imaging, decreased from an average of 1.85 on the Sheriff-Saadeh scale, before surgery, to 0.15 twelve months after surgery (p &lt; 0.001). As regards liver enzymes, the level of alanine aminotransferase decreased from 64.5 (U/l) to 27.95 (U/l) (p &lt; 0.001), and the level of aspartate aminotransferase decreased from 54.4 (U/l) to 27.2 (U/l).

CONCLUSIONS

Bariatric procedures not only lead to a significant and lasting weight loss, but they also contribute to the reduction of fatty liver disease and improve liver function.

Dietary Inflammatory Index and liver status in subjects with different adiposity levels within the PREDIMED trial

BACKGROUND & AIMS

To assess the possible association between a validated Dietary Inflammatory Index (DII) and specific dietary components with suitable non-invasive markers of liver status in overweight and obese subjects within the PREDIMED study.

METHODS

A cross-sectional study encompassing 794 randomized overweight and obese participants (mean ± SD age: 67.0 ± 5.0 y, 55% females) from the PREDIMED (PREvención con DIeta MEDiterránea) trial was conducted. DII is a validated tool evaluating the effect of diet on six inflammatory biomarkers (IL-1b, IL-4, IL-6, IL-10, TNF-α and C-reactive protein). Furthermore, a validated 137-item food-frequency-questionnaire was used to obtain the information about the food intake. In addition, anthropometric measurements and several non-invasive markers of liver status were assessed and the Fatty Liver Index (FLI) score was calculated.

RESULTS

A higher DII and lower adherence to Mediterranean diet (MeDiet) were associated with a higher degree of liver damage (FLI > 60) in obese as compared to overweight participants. Furthermore, the DII score was positively associated with relevant non-invasive liver markers (ALT, AST, GGT and FLI) and directly affected FLI values. Interestingly, a positive correlation was observed between liver damage (>50th percentile FLI) and nutrients and foods linked to a pro-inflammatory dietary pattern.

CONCLUSIONS

This study reinforced the concept that obesity is associated with liver damage and revealed that the consumption of a pro-inflammatory dietary pattern might contribute to obesity and fatty liver disease features. These data suggest that a well-designed precision diet including putative anti-inflammatory components could specifically prevent and ameliorate non-alcoholic fatty liver manifestations in addition to obesity.

NAFLD as a Sexual Dimorphic Disease: Role of Gender and Reproductive Status in the Development and Progression of Nonalcoholic Fatty Liver Disease and Inherent Cardiovascular Risk

Nonalcoholic fatty liver disease (NAFLD) spans steatosis through nonalcoholic steatohepatis, cirrhosis, and hepatocellular carcinoma (HCC) associated with striking systemic features and excess cardiovascular and liver-related mortality. The pathogenesis of NAFLD is complex and multifactorial. Endocrine derangements are closely linked with dysmetabolic traits. For example, in animal and human studies, female sex is protected from dysmetabolism thanks to young individuals’ ability to partition fatty acids towards ketone body production rather than very low density lipoprotein (VLDL)-triacylglycerol, and to sex-specific browning of white adipose tissue. Ovarian senescence facilitates both the development of massive hepatic steatosis and the fibrotic progression of liver disease in an experimental overfed zebrafish model. Consistently, estrogen deficiency, by potentiating hepatic inflammatory changes, hastens the progression of disease in a dietary model of nonalcoholic steatohepatitis (NASH) developing in ovariectomized mice fed a high-fat diet. In humans, NAFLD more often affects men; and premenopausal women are equally protected from developing NAFLD as they are from cardiovascular disease. It would be expected that early menarche, definitely associated with estrogen activation, would produce protection against the risk of NAFLD. Nevertheless, it has been suggested that early menarche may confer an increased risk of NAFLD in adulthood, excess adiposity being the primary culprit of this association. Fertile age may be associated with more severe hepatocyte injury and inflammation, but also with a decreased risk of liver fibrosis compared to men and postmenopausal status. Later in life, ovarian senescence is strongly associated with severe steatosis and fibrosing NASH, which may occur in postmenopausal women. Estrogen deficiency is deemed to be responsible for these findings via the development of postmenopausal metabolic syndrome. Estrogen supplementation may at least theoretically protect from NAFLD development and progression, as suggested by some studies exploring the effect of hormonal replacement therapy on postmenopausal women, but the variable impact of different sex hormones in NAFLD (i.e., the pro-inflammatory effect of progesterone) should be carefully considered.

Emodin alleviates hepatic steatosis by inhibiting sterol regulatory element binding protein 1 activity by way of the calcium/calmodulin-dependent kinase kinase-AMP-activated protein kinase-mechanistic target of rapamycin-p70 ribosomal S6 kinase signaling pathway

AIM

To investigate the effects of emodin on the treatment of non-alcoholic fatty liver and the underlying mechanisms.

METHODS

In vitro, hepatocytes were treated with 1 mM free fatty acid together with various concentrations of emodin. In vivo, Sprague-Dawley rats were divided into a control group, high-fat diet (HFD) group, and three HFD groups treated with 40, 80, and 160 mg/kg emodin, respectively. After being fed a HFD for 4 weeks, rats were orally dosed with emodin once daily for 8 weeks. The biochemical parameters and histology features were examined. The expression of lipogenic and lipolytic gene and protein and the phosphorylation of calcium/calmodulin-dependent kinase kinase (CaMKK), AMP-activated protein kinase (AMPK), mechanistic target of rapamycin (mTOR) and p70 ribosomal S6 kinase (p70S6K) were measured in vitro and in vivo.

RESULTS

Emodin improved lipid accumulation in vitro and in vivo. Emodin downregulated the levels of sterol regulatory element binding protein 1 (SREBP1) and its target enzymes but increased lipolysis-related proteins and mRNA. Phosphorylation of AMPK was increased, while phosphorylation of mTOR and p70S6K were suppressed by emodin. The nuclear translocation of SREBP1 was inhibited by emodin by AMPK and mTOR. Emodin activated AMPK by CaMKK and reversed the reduction of CaMKK in HFD-fed rats.

CONCLUSION

Emodin effectively ameliorates hepatic steatosis through the CaMKK-AMPK-mTOR-p70S6K-SREBP1 signaling pathway.

Bi-directional analysis between fatty liver and cardiovascular disease risk factors

BACKGROUND & AIMS

The relations of non-alcoholic fatty liver disease to cardiovascular disease (CVD) risk factors are not fully understood. The objective of our study is to explore the bi-directional relationships of fatty liver to CVD risk factors.

METHODS

We prospectively evaluated whether liver fat predicted the development of CVD risk factors and whether CVD risk factors predicted new onset fatty liver during 6years of follow-up in middle- to older-aged Framingham Heart Study participants. We estimated liver fat using multi-detector computed tomography.

RESULTS

We included 1051 participants (mean age 45±6years, 46% women). The prevalence of fatty liver was 18% at baseline. In participants without fatty liver at baseline, 101 participants developed incident fatty liver over approximately 6years. Baseline liver fat (per standard deviation increase) was associated with increased odds of incident hypertension (OR 1.42; 95% CI 1.15-1.76; p=0.001) and incident type 2 diabetes (OR 1.43; 95% CI 1.09-1.88, p<0.001). In a parallel analysis, individuals with hypertension (OR 3.34; 95% CI 2.04-5.49), hypertriglyceridemia (OR 3.04; 95% CI: 1.84-5.02), impaired fasting glucose (OR 2.92; 95% CI 1.76-4.82), or type 2 diabetes (OR 4.15; 95% CI 1.19-14.46) at baseline had higher odds of incident fatty liver compared to individuals without those conditions (all p<0.03). In both analyses, the observed associations remained similar after additional adjustments for measures of adiposity.

CONCLUSIONS

The present study demonstrated bi-directional relationships between fatty liver and CVD risk factors among middle- to older-aged Framingham Heart Study participants.

LAY SUMMARY

It is not fully understood whether non-alcoholic fatty liver (NAFLD) disease precedes or develops after increased cardiovascular disease (CVD) risk factors. The findings of our study suggest a bi-directional relationship between NAFLD and CVD risk factors.

Effect of exercise on the development of new fatty liver and the resolution of existing fatty liver

BACKGROUND & AIMS

Guidelines about recommendations for amounts of exercise/physical activity are variable in non-alcoholic fatty liver disease. Our aim was to determine the amount of exercise that was associated with two outcomes: a) development of incident liver fat and b) resolution of baseline liver fat, at five-year follow-up.

METHODS

In an occupational health screening program, weekly frequency of exercise was assessed using the validated Korean version of the International Physical Activity Questionnaire Short Form (IPAQ-SF). Liver fat was identified by ultrasonography (3.5MHz probe) at baseline and at five-year follow-up. Fully adjusted Cox proportional hazards models were used to estimate hazard ratios (HRs and 95% confidence intervals [CI]) for incident fatty liver and resolution of fatty liver at follow-up.

RESULTS

233,676 men and women were studied between 2002 and 2014. 126,811 individuals were identified without fatty liver, and of these subjects, 29,014 subjects developed incident fatty liver during follow-up. At baseline, there were 42,536 individuals with liver fat and of these individuals, fatty liver resolved in 14,514, during follow-up. After full adjustment, compared to no exercise, exercise was associated with benefit for both outcomes; for exercise ⩾5times per week for incident fatty liver: HR 0.86 (95% CI 0.80,0.92), p<0.001, and for resolution of fatty liver HR 1.40 (95% CI 1.25,1.55), p<0.001.

CONCLUSIONS

Moderate to vigorous exercise is beneficial in decreasing risk of development of new fatty liver or improving resolution of existing fatty liver during 5years of follow-up.

LAY SUMMARY

The amount of exercise/physical activity to benefit fatty liver disease in non-alcoholic fatty liver disease is not known. In a large study of free-living people, our aim was to determine the amount of exercise that was linked with a decrease in new fatty liver and also improvement of existing fatty liver over 5years of follow-up. Compared to no exercise, exercise ⩾5times per week (lasting at least 10min on each occasion) was linked to a highly significantly benefit for both a decrease in new fatty liver and also improvement of existing fatty liver.

Prevalence and Factors Associated with Nonalcoholic Fatty Liver Disease in a Nonobese Korean Population

Background/Aims

Nonalcoholic fatty liver disease (NAFLD) is an emerging problem in Asia, but little is known about the disease in the nonobese population. The aims of this study were to investigate the prevalence of NAFLD and the factors associated with it in a nonobese Korean population and to compare the clinical characteristics of nonobese and obese subjects with NAFLD.

Methods

This cross-sectional study used data from 2,058 subjects who participated in a medical checkup program.

Results

The prevalence of NAFLD was 12.4% (213/1,711) in the nonobese population. A higher body mass index (BMI), higher homeostasis model assessment of insulin resistance (HOMA-IR) values, higher alanine aminotransferase (ALT) levels, triglyceride concentrations 150 mg/dL, and hyperuricemia were independently associated with the presence of NAFLD in the nonobese subjects. Compared with the obese subjects with NAFLD, the nonobese subjects with NAFLD were composed of a higher proportion of females and had lower BMIs, smaller waist circumferences, lower HOMA-IR values, and fewer metabolic irregularities.

Conclusions

Higher BMIs, HOMA-IR values, ALT levels, hypertriglyceridemia, and hyperuricemia were associated with NAFLD in the nonobese subjects. Clinicians should be particularly aware of the possibility of NAFLD in nonobese Asian people.

Differences in metabolic biomarkers in the blood and gene expression profiles of peripheral blood mononuclear cells among normal weight, mildly obese and moderately obese subjects

We compared metabolic biomarkers in the blood and peripheral blood mononuclear cell (PBMC) gene expression profiles among normal weight (BMI, 18·5–23 kg/m2), mildly obese (BMI, 25–27·5 kg/m2) and moderately obese Korean adult men (BMI, 27·5–30 kg/m2). High leptin, lipids (except LDL- and HDL-cholesterol) and apoB levels and low adiponectin and HDL-cholesterol levels were present in the plasma of both mildly and moderately obese subjects. Circulating levels of inflammatory cytokines and markers of insulin resistance, oxidative stress and liver damage were altered in moderately obese subjects but not in mildly obese subjects. PBMC transcriptome data showed enrichment of pathways involved in energy metabolism, insulin resistance, bone metabolism, cancer, inflammation and fibrosis in both mildly and moderately obese subjects. Signalling pathways involved in oxidative phosphorylation, TAG synthesis, carbohydrate metabolism and insulin production; mammalian target of rapamycin, forkhead box O, ras-proximate-1, RAS and transforming growth factor-β signalling; as well as extracellular matrix–receptor interaction were enriched only in moderately obese subjects, indicating that changes in PBMC gene expression profiles, according to metabolic disturbances, were associated with the development and/or aggravation of obesity. In particular, fourteen and fifteen genes differentially expressed only in mildly obese subjects and in both mildly and moderately obese subjects, respectively, could be used as early or stable biomarkers for diagnosing and treating obesity-associated metabolic disturbance. We characterised BMI-associated metabolic and molecular biomarkers in the blood and provided clues about potential blood-based targets for preventing or treating obesity-related complications.

Epidemiology of Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis in the United States and the Rest of the World

Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease with increasing prevalence, which can progress to cirrhosis and liver failure. Because of the obesity epidemic and increasing prevalence of metabolic syndrome, NAFLD and its progressive form, nonalcoholic steatohepatitis, are seen more commonly in different parts of the world. This article reviews the worldwide epidemiology of NAFLD and nonalcoholic steatohepatitis. The PubMed database was used to identify studies related to epidemiology of NAFLD in the adult population. It is estimated that the epidemic of obesity will continue to fuel the burden of NAFLD and its long-term complications.

Prevalence of and predictive factors for nonalcoholic fatty liver disease in Sudanese individuals with type 2 diabetes: Is metabolic syndrome the culprit?

BACKGROUND AND STUDY AIM

Non-alcoholic fatty liver disease (NAFLD) is a common global chronic liver condition. The prevalence of NAFLD among individuals with type 2 diabetes is estimated to be as high as 75%. The aim of this study was to determine the prevalence of NAFLD among individuals with type 2 diabetes in Sudan.

PATIENTS AND METHODS

This was a cross-sectional hospital-based study, which was carried out at the Jabir Abu-Elizz diabetic centre in Khartoum; 167 outpatients with type 2 diabetes were enrolled. NAFLD was diagnosed based on ultrasound, following exclusion of significant alcohol intake and secondary causes of liver diseases. NAFLD was defined as hepatic steatosis in the absence of alcohol intake, medication, previous liver disease and negative results for the serological test for hepatitis B and C. Logistic regression analysis was used to determine independent risk factors for the development of NAFLD in individuals with type 2 diabetes.

RESULTS

The number of female subjects was 89 (53.3%), and most subjects (145, 86.8%) were between the ages of 40 and 70 years. The overall prevalence of fatty liver among individuals with type 2 diabetes was found to be 50.3%. Age, duration of diabetes, hypertension and HbA1c levels appeared to have no impact on the prevalence of NAFLD. The possible predictors of NAFLD were overweight, obesity, central obesity, high triglyceride level and low high-density lipoprotein cholesterol (HDL-c) level. A higher prevalence of NAFLD was observed in individuals with three components of the metabolic syndrome.

CONCLUSION

NAFLD was observed in half of the diabetic population, and its occurrence correlates positively with metabolic syndrome risk factors.

NAFLD: a multisystem disease

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in Western countries that is predicted to become also the most frequent indication for liver transplantation by 2030. Over the last decade, it has been shown that the clinical burden of NAFLD is not only confined to liver-related morbidity and mortality, but there is now growing evidence that NAFLD is a multisystem disease, affecting extra-hepatic organs and regulatory pathways. For example, NAFLD increases risk of type 2 diabetes mellitus (T2DM), cardiovascular (CVD) and cardiac diseases, and chronic kidney disease (CKD). Although the primary liver pathology in NAFLD affects hepatic structure and function to cause morbidity and mortality from cirrhosis, liver failure and hepatocellular carcinoma, the majority of deaths among NAFLD patients are attributable to CVD. This narrative review focuses on the rapidly expanding body of clinical evidence that supports the concept of NAFLD as a multisystem disease. The review discusses the factors involved in the progression of liver disease in NAFLD and the factors linking NAFLD with other extra-hepatic chronic diseases, such as T2DM, CVD, cardiac diseases and CKD. The review will not discuss NAFLD treatments as these are discussed elsewhere in this issue of the Journal. For this review, PubMed was searched for articles using the keywords "non-alcoholic fatty liver disease" or "fatty liver" combined with "diabetes", "cardiovascular (or cardiac) disease", "cardiovascular mortality" or "chronic kidney disease" between 1990 and 2014. Articles published in languages other than English were excluded.

Comorbidities and Metabolic Derangement of NAFLD

Nonalcoholic fatty liver disease (NAFLD) is an increasingly common cause of chronic liver disease worldwide and is becoming a major public health problem. NAFLD has been recognized as a hepatic manifestation of metabolic syndrome linked with insulin resistance. Growing evidence supports that NAFLD is associated with systemic diseases such as cardiovascular disease (CVD), chronic kidney disease (CKD), type 2 diabetes, obesity, and metabolic syndrome. The majority of deaths in patients with NAFLD come from cardiovascular disease. These findings are strongly attributed to nonalcoholic steatohepatitis (NASH) rather than simple steatosis. NAFLD should be considered not only a liver specific disease but also an early mediator of systemic disease. The underlying mechanisms and pathogenesis of NAFLD with regard to other medical disorders are not yet fully understood. Further investigation is needed for future therapeutic strategies for NAFLD. This review focuses on the relationship between NAFLD and various comorbid diseases and metabolic derangement.

Nonalcoholic Fatty liver disease and risk of diabetes and cardiovascular disease: what is important for primary care physicians?

Nonalcoholic fatty liver disease (NAFLD) is emerging as the most common chronic liver condition in Western World and across the globe. NAFLD prevalence is estimated to be around one-third of the total population. There are no published data that project the future prevalence of NAFLD, but with an increase in epidemic of diabetes and obesity, it is possible to suggest an increase in a number of individuals with NAFLD. NAFLD is associated with insulin resistance and occurs with an increase in cluster of features of metabolic syndrome and type 2 diabetes. Therefore, it is important to exclude the possibility of diabetes in those individuals with evidence of fatty liver. The global diabetes epidemic continues to grow, and it is estimated that the number of people with diabetes will double by year 2030. NAFLD is also a risk factor for an increase in cardiovascular incidence independent of age, sex, low-density lipoprotein-cholesterol, smoking, and cluster of metabolic syndromes. It is expected that NAFLD will be an important challenge for health providers in the near future. Taking all these factors into consideration, we believe that increasing awareness of metabolic and cardiovascular impact of NAFLD among general practitioners and health authorities may decrease the serious consequences of late diagnosis of NAFLD. Importantly, the collaboration between medical specialties is vital in decreasing the impact of the epidemic of NAFLD. The focus of this review is in the role of primary care physician in diagnosis, treatment and prevention of NAFLD and patients education.