A "systems medicine" approach to the study of non-alcoholic fatty liver disease

Nutritional intervention in the management of non-alcoholic fatty liver disease

Lifestyle modification is the primary intervention to control NAFLD progression, but despite evidence-based effectiveness it is difficult to distinguish the benefits of nutrition from physical activity and the optimal diet composition is not established. Macronutrients as saturated fatty acids, sugars and animal proteins are harmful in NAFLD and the Mediterranean Diet reducing sugar, red meat and refined carbohydrates and increasing unsaturated-fatty-acids was reported to be beneficial. However one size cannot fit all since NAFLD is a multifaceted syndrome encompassing many diseases of unknown etiologies, different clinical severity and outcomes. Studies of the intestinal metagenome, provided new insights into the physio-pathological interplay between intestinal microbiota and NAFLD. How much the microbiota heterogeneity can influence response to diet remains unknown. New knowledge indicates that AI guided personalized nutrition based on clinic-pathologic and genetic data combined with pre/post nutritional intervention gut metagenomics/metabolomics will be part of the future management of NAFLD.

Critical Overview of Hepatic Factors That Link Non-Alcoholic Fatty Liver Disease and Acute Kidney Injury: Physiology and Therapeutic Implications

Non-alcoholic fatty liver disease (NAFLD) is defined as a combination of a group of progressive diseases, presenting different structural features of the liver at different stages of the disease. According to epidemiological surveys, as living standards improve, the global prevalence of NAFLD increases. Acute kidney injury (AKI) is a class of clinical conditions characterized by a rapid decline in kidney function. NAFLD and AKI, as major public health diseases with high prevalence and mortality, respectively, worldwide, place a heavy burden on societal healthcare systems. Clinical observations of patients with NAFLD with AKI suggest a possible association between the two diseases. However, little is known about the pathogenic mechanisms linking NAFLD and AKI, and the combination of the diseases is poorly treated. Previous studies have revealed that liver-derived factors are transported to distal organs via circulation, such as the kidney, where they elicit specific effects. Of note, while NAFLD affects the expression of many hepatic factors, studies on the mechanisms whereby NAFLD mediates the generation of hepatic factors that lead to AKI are lacking. Considering the unique positioning of hepatic factors in coordinating systemic energy metabolism and maintaining energy homeostasis, we hypothesize that the effects of NAFLD are not only limited to the structural and functional changes in the liver but may also involve the entire body via the hepatic factors, e.g., playing an important role in the development of AKI. This raises the question of whether analogs of beneficial hepatic factors or inhibitors of detrimental hepatic factors could be used as a treatment for NAFLD-mediated and hepatic factor-driven AKI or other metabolic disorders. Accordingly, in this review, we describe the systemic effects of several types of hepatic factors, with a particular focus on the possible link between hepatic factors whose expression is altered under NAFLD and AKI. We also summarize the role of some key hepatic factors in metabolic control mechanisms and discuss their possible use as a preventive treatment for the progression of metabolic diseases.

Comprehensive Review and Updates on Holistic Approach Towards Non-Alcoholic Fatty Liver Disease Management with Cardiovascular Disease

PURPOSE OF REVIEW

The global prevalence of non-alcoholic fatty liver disease (NAFLD) presents an unmet need in treating these, often asymptomatic, individuals. In this review, we summarised NAFLD management and described recent developments in non-alcoholic steatohepatitis (NASH) therapeutics that can shape the future of NAFLD.

RECENT FINDINGS

A multi-disciplinary effort in promoting sustainable lifestyle measures is paramount, with the goal of either limiting energy surplus alone or in combination with targeting downstream pathways of inflammation and fibrosis. Several antidiabetic medications like PPAR-γ agonist and glucagon-like peptide receptor agonists have beneficial effects on the metabolic profile as well as NASH histology. Vitamin E has shown promise in specific groups of patients with the haptoglobin2 allele protein. Newer drugs have demonstrated promising results in NASH resolution and fibrosis improvement such as obeticholic acid, resmetirom, aramchol, efruxifermin, aldafermin and lanifibranor. Apart from discussing the results of late stage clinical trials and the possible challenges in managing these patients with limited approved therapies, we also discussed the specific management of comorbidities (diabetes, hypertension, hyperlipidaemia, cardiovascular diseases) in NAFLD patients. Treatment strategy needs to target improvements in liver-related outcomes and cardiometabolic profile.

Non-alcoholic fatty liver disease association with structural heart, systolic and diastolic dysfunction: a meta-analysis

OBJECTIVE

Several studies have documented a relationship between non-alcoholic fatty liver disease (NAFLD) and structural heart disease, particularly diastolic function. This meta-analysis will be the first to examine the echocardiographic-derived cardiac function and structural characteristics in NAFLD patients, and its association with liver disease severity and metabolic profile.

METHODS

Medline and Embase were searched and pairwise meta-analysis was conducted in DerSimonian and Laird to obtain the odds ratio (OR) and mean difference (MD) for dichotomous and continuous variables, respectively, to compare the effects of NAFLD on the echocardiography parameters.

RESULTS

Forty-one articles involving 33,891 patients underwent echocardiography. NAFLD patients had worse systolic indices with lower ejection fraction (EF, MD: - 0.693; 95% CI: - 1.112 to - 0.274; p = 0.001), and worse diastolic indices with higher E/e' (MD: 1.575; 95% CI: 0.924 to 2.227; p < 0.001) compared to non-NAFLD patients. NAFLD patients displayed increased left ventricular mass (LVM, MD: 34.484; 95% CI: 26.236 to 42.732; p < 0.001) and epicardial adipose thickness (EAT, MD: 0.1343; 95% CI: 0.055 to 0.214; p = 0.001). An increased severity of NAFLD was associated with worse diastolic indices (decreased E/A ratio, p = 0.007), but not with systolic indices.

CONCLUSIONS

NAFLD is associated with impaired systolic and diastolic function with changes in cardiac structure. Concomitant metabolic risk factors and liver disease severity are independently associated with worsening systolic and diastolic function.

Fibrosis Predictive Score in Caucasian Patients with Metabolic Syndrome

INTRODUCTION

Many of the patients presenting with metabolic syndrome (MetS) also have liver steatosis (NAFLD) and some of them could develop liver fibrosis.

PURPOSE

To develop a simple score that could rule out fibrosis, especially significant fibrosis (F≥2) and could be used in daily practice in patients with MetS, in order to identify patients at risk.

PATIENTS AND METHODS

A total of 204 patients with MetS were prospectively enrolled. Evaluation of liver fibrosis was made using Vibration Controlled Transient Elastography while evaluation of steatosis was achieved using ultrasound (US).

RESULTS

Out of 204 patients with MetS, 179 patients (87.7%) had reliable liver stiffness measurements and 22.9% (41/179) had F ≥2. To formulate the fibrosis predicting score, all clinical variables associated with F ≥2 in the univariate analysis were considered in a multivariate regression model. According to the power of correlation, by consensus, we attributed 1 point for BMI >31.4 kg/m², 1 point for female gender, 1 point for HDLc <47mg/dL, 1 point for mild steatosis at US, 1.5 point for moderate and 2 points for severe steatosis.

CONCLUSION

At an optimal cut-off value of <3.5, our score could be used to rule-out the risk for developing at least significant fibrosis with a high negative predictive value (NPV 89.2%) in patients with MetS.

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.

Liver Fibrosis Biomarkers Accurately Exclude Advanced Fibrosis and Are Associated with Higher Cardiovascular Risk Scores in Patients with NAFLD or Viral Chronic Liver Disease

Liver fibrosis predicts liver-related and cardiovascular outcomes in chronic liver disease patients. We compared the diagnostic performance of various liver fibrosis biomarkers for identifying histological significant/advanced fibrosis. Additionally, the correlations of such liver fibrosis biomarkers with cardiovascular risk (CVR) scores were evaluated. 173 patients with viral hepatitis (157 HCV and 16 HBV) and 107 with a non-alcoholic fatty liver disease (NAFLD) were consecutively enrolled. Various liver fibrosis biomarkers: aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio (ARR), AST to Platelet Ratio Index (APRI), Fibrosis-4 (FiB-4), Forns index, NAFLD fibrosis score (NFS), BARD (body mass index (BMI), AAR, Diabetes) score, and Hepamet fibrosis score (HFS), were used to identify significant/advanced fibrosis. CVR was assessed by using the SCORE, the Progetto CUORE, or the Framingham risk scoring systems. Liver fibrosis biomarkers performed better in predicting advanced rather than significant liver fibrosis in all patients, regardless of chronic liver disease aetiology. Forns index and HFS performed best in predicting advanced fibrosis in patients with viral chronic liver disease and NAFLD. Lower cut-offs of these liver fibrosis biomarkers had high negative predictive values for advanced fibrosis overall, as well as in patients with NAFLD or viral chronic liver disease. FIB-4, Forns index, NFS, and HFS were positively correlated with SCORE and Framingham risk scores. In conclusion, liver fibrosis biomarkers accurately exclude advanced fibrosis and positively correlate with CVR scores in patients with chronic liver disease.

Efficacy of Sodium-Glucose Cotransporter 2 Inhibitors in Patients With Concurrent Type 2 Diabetes Mellitus and Non-Alcoholic Steatohepatitis: A Review of the Evidence

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disease worldwide, and more than half of individuals diagnosed with type 2 diabetes concurrently present with NAFLD. There is a bidirectional pathological relationship between the two conditions, whereby NAFLD increases the risk of type 2 diabetes, and type 2 diabetes contributes to and accelerates the progression of NAFLD. Furthermore, over 30% of patients with NAFLD progress to non-alcoholic liver steatohepatitis (NASH), which then increases the risk of cirrhosis and hepatocellular carcinoma. Despite its high prevalence and the potential clinical implications, the underlying pathogenesis of NAFLD has yet to be fully elucidated, and there is no consensus regarding standard diagnosis and treatment for either NALFD or NASH. As patients with both NASH and type 2 diabetes have impaired hepatic function owing to chronic inflammation and the resulting structural changes caused by hepatic fat accumulation, they face reduced options for antidiabetic treatment. SGLT-2 inhibitors inhibit glucose reabsorption in the proximal tubule, with increased excretion of glucose in urine and decreased glucose levels in plasma, and their glycemia-lowering effect is insulin-independent. Several other beneficial effects have been reported for SGLT-2 inhibitors, including reduced risks of cardiovascular and renal diseases, improved blood pressure control, body weight reduction, and reductions in liver fat content. Experimental studies in mouse models have suggested that SGLT-2 inhibitors may have beneficial modulatory effects on NAFLD/NASH. Several trials in patients with type 2 diabetes have also suggested that these drugs may be useful in treating both type 2 diabetes and NAFLD or NASH. However, further research is needed to identify the mechanisms by which SGLT-2 inhibitors affect fatty liver and steatohepatitis. In this state-of-the-art review, we explore the literature on the efficacy of SGLT-2 inhibitors in patients with type 2 diabetes and NASH, and present arguments for and against the use of SGLT-2 inhibitors in this patient population.

Metabolic syndrome and COVID-19: An update on the associated comorbidities and proposed therapies

BACKGROUND AND AIMS

Many patients with coronavirus disease 2019 (COVID-19) have comorbidities related to metabolic syndrome (MS) during the disease course. Its presence in different ethnicities and continents places MS as an important risk factor for COVID-19. Adequate understanding of the interplay between MS, COVID-19 and proposed therapies is required for optimum management of these patients.

METHODS

We systematically searched the PubMed and Google Scholar databases until June 1st, 2020 and accessed the full text on COVID-19 and MS to prepare a narrative review on this topic.

RESULTS

Patients with metabolic disorders like obesity, diabetes, cardiovascular and liver disease may face a higher risk of infection of COVID-19, greatly affecting the development and prognosis of the disease, being associated with significantly worse outcome in these patients. The proposed drugs that are in clinical trial for COVID-19 treatment must be carefully considered for clinical use, especially in patients with MS.

CONCLUSION

MS is a risk factor influencing the progression and prognosis of COVID-2019. The drugs currently evaluated for the infection treatment are promising but need further studies to prove their efficacy and safety, due to the adverse effects may be exacerbated by combination therapy or due to viral infection. The development of a vaccine for immunization is still the best long-term solution.

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.

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.

Programming of hepatic lipid metabolism in a rat model of postnatal nicotine exposure - Sex-related differences

Maternal nicotine exposure during lactation induces liver damage in adult male rats. However, the mechanism in males is unknown and females have not been tested. Here, we determined the liver lipid composition and lipogenic enzymes in male and female offspring at two ages in a model of postnatal nicotine exposure. Osmotic minipumps were implanted in lactating Wistar rat dams at postnatal day (PND) 2 to release 6 mg/kg/day of nicotine (NIC group) or saline (CON group) for 14 days. Offspring received a standard diet from weaning until euthanasia at PND120 (1 pup/litter/sex) or PND180 (2 pups/litter/sex). At PND120, NIC males showed lower plasma triglycerides (TG), steatosis degree 1, higher hepatic cholesterol (CHOL) ester, free fatty acids, monoacylglycerol content as well as acetyl-coa carboxylase-1 (ACC-1) and fatty acid synthase (FAS) protein expression in the liver compared to CON males. At this age, NIC females had preserved hepatocytes architecture, higher plasma CHOL, higher CHOL ester and lower total CHOL content in the liver compared to CON females. At PND180, NIC males showed steatosis degrees 1 and 2, higher TG, lower free fatty acids and total CHOL content in the liver and an increase in ACC-1 hepatic protein expression. NIC females had higher plasma TG and CHOL levels, no change in hepatic morphology, lower CHOL ester and free fatty acids in the liver, which also showed higher total ACC-1 and FAS protein expression. Maternal nicotine exposure induces long-term liver dysfunction, with an alteration in hepatic cytoarchitecture that was aggravated with age in males. Concerning females, despite unchanged hepatic cytoarchitecture, lipid metabolism was compromised, which deserves further attention.

Contribution of a genetic risk score to clinical prediction of hepatic steatosis in obese children and adolescents

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is the commonest liver disease in children and adolescents in Western countries. Complex traits arise from the interplay between environmental and genetic factors in the pathogenesis of NAFLD.

AIMS

We examined the association between NAFLD and eleven single nucleotide polymorphisms (SNPs) at genetic loci potentially associated with liver damage (GCKR, MBOAT7, GPR120), oxidative stress (SOD2), lipid metabolism (PNPLA3, TM6SF2, LPIN1, ELOVL2, FADS2, MTTP) and fibrogenesis (KLF6) in a paediatric population. A genetic risk score (GRS) was performed taking into account both these SNPs and clinical risk factors.

METHODS

We recruited a cohort of 514 obese children and adolescents (mean age [±SD]: 11.2 ± 2.8 years, z-BMI 3.3 ± 0.8). NAFLD was identified by ultrasonography. Genotyping was performed by TaqMan-based RT-PCR system.

RESULTS

The overall prevalence of NAFLD was 67.5% (347 patients). Among the eleven genotyped SNPs, the genetic variants in TM6SF2 rs58542926 (OR = 4.13, p = 0.002), GCKR rs1260326 (OR = 1.53, p = 0.003), PNPLA3 rs738409 (OR = 1.58, p = 0.004) and ELOVL2 rs2236212 (OR = 1.34, p = 0.047) were significantly associated with a higher risk of NAFLD. Addition of a 11-polymorphism GRS to established clinical risk factors significantly (albeit modestly) improved the discriminatory capability of the regression model for predicting the risk of NAFLD (with SNPs C-statistic 0.81 [95%CI 0.75-0.88] vs. 0.77 [0.70-0.84] without SNPs; p = 0.047).

CONCLUSIONS

NAFLD was strongly associated with three genetic variants, TM6SF2 rs58542926, PNPLA3 rs738409 and GCKR rs1260326, and more slightly with ELOVL2 rs2236212, in obese children and adolescents. Addition of a 11-polymorphism GRS to clinical risk factors improved the predictability of NAFLD.

Homeostasis of Glucose and Lipid in Non-Alcoholic Fatty Liver Disease

Industrialized society-caused dysregular human behaviors and activities such as overworking, excessive dietary intake, and sleep deprivation lead to perturbations in the metabolism and the development of metabolic syndrome. Non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease worldwide, affects around 30% and 25% of people in Western and Asian countries, respectively, which leads to numerous medical costs annually. Insulin resistance is the major hallmark of NAFLD and is crucial in the pathogenesis and for the progression from NAFLD to non-alcoholic steatohepatitis (NASH). Excessive dietary intake of saturated fats and carbohydrate-enriched foods contributes to both insulin resistance and NAFLD. Once NAFLD is established, insulin resistance can promote the progression to the more severe state of liver endangerment like NASH. Here, we review current and potential studies for understanding the complexity between insulin-regulated glycolytic and lipogenic homeostasis and the underlying causes of NAFLD. We discuss how disruption of the insulin signal is associated with various metabolic disorders of glucoses and lipids that constitute both the metabolic syndrome and NAFLD.

Non-alcoholic fatty liver disease is associated with low-grade albuminuria in men without diabetes mellitus

Background: Non-alcoholic fatty liver disease (NAFLD) is associated with the dysregulation of multiple metabolic and inflammatory pathways. These can lead to extrahepatic disorders involving the kidney, a vulnerable organ responsible for extra-renal complications. Evaluating the association between NAFLD and low-grade albuminuria as a renal complication would be helpful to better understand the pathophysiology and extra-hepatic complications of NAFLD. Patients and Methods: Our study extracted data from database obtained a representative population sample. Overall, 3867 men were included in this survey. Our study included only men without diabetes mellitus, with a urinary albumin/creatinine ratio < 30 mg/g (n = 1390). Low-grade albuminuria was defined by a urinary albumin/creatinine ratio within the highest quartile. The fatty liver index was calculated in accordance with Bedogni's equation. We defined the NAFLD group as patients with a fatty liver index of ≥ 60. Results: In the multivariate analysis, the urinary albumin/creatinine ratio in the non-NAFLD and NAFLD groups was 3.05 ± 0.14 and 5.19 ± 0.42, respectively (P < 0.001). The correlation coefficients between the fatty liver index and urinary albumin/creatinine ratio were 0.124 in the Pearson's correlation test and 0.084 in the partial correlation test (P < 0.001 and P = 0.002, respectively). Linear regression analysis showed a positive association between the fatty liver index and the urinary albumin/creatinine ratio on multivariate analysis. Logistic regression analysis showed that the odds ratio for low-grade albuminuria with NAFLD was 2.31 (95% confidence interval, 1.47-3.61; P < 0.001) on the multivariate analysis. Subgroup analyses according to the presence of metabolic syndrome or age (< 50 or ≥ 50 years) showed that the association between NAFLD and the urinary albumin/creatinine ratio was stronger for participants without metabolic syndrome and in those aged < 50 years. Conclusion: NAFLD was associated with low-grade albuminuria in men without diabetes mellitus in this study. Therefore, men with a relatively high fatty liver index or NAFLD should be closely monitored for low-grade albuminuria, especially in absence of metabolic syndrome.

Hypothyroidism and nonalcoholic fatty liver disease - a chance association?

Background Nonalcoholic fatty liver disease (NAFLD) defines the clinical-pathological spectrum of hepatic lipotoxicity, which may progress to hepatic fibrosis and its complications. Thyroid hormone is a master regulator of cell metabolism and body fat distribution. Whether hypothyroidism is associated or not with an increased risk of developing NAFLD and its fibrotic progression is both clinically and physiopathologically relevant. Indeed, answering this research question would carry major pathogenic and therapeutic implications. Method PubMed database was searched using relevant key-words such as hypothyroidism; NAFLD; nonalcoholic steatohepatitis; cirrhosis; hepatocellular carcinoma; epidemiology; pathogenesis; natural history. The epidemiological studies and the meta-analyses published so far were identified as well as those studies addressing the physiopathology underlying this association. Results Many observational studies have investigated the association between either subclinical or overt hypothyroidism and NAFLD. Data are conflicting: some original and meta-analytical studies demonstrated that hypothyroidism, (mainly subclinical hypothyroidism), was common, occurring in approximately 25% of individuals with imaging-defined or biopsy-proven NAFLD; other studies, however, failed to identify a significant association between hypothyroidism and NAFLD. Moreover, such an association is biologically plausible based on the specific physiopathological impact of thyroid hormone and thyroid stimulating hormone (TSH) on metabolism of hepatocytes and accumulation and distribution of body fat. Conclusions The findings from the present review support a significant association between primary hypothyroidism and risk of development and progression of NAFLD. However, further studies evaluating the relative importance of subclinical versus overt hypothyroidism as well as addressing the mechanisms underlying the association of hypothyroidism with NAFLD are eagerly awaited.

LiverSex Computational Model: Sexual Aspects in Hepatic Metabolism and Abnormalities

The liver is to date the best example of a sexually dimorphic non-reproductive organ. Over 1,000 genes are differentially expressed between sexes indicating that female and male livers are two metabolically distinct organs. The spectrum of liver diseases is broad and is usually prevalent in one or the other sex, with different contributing genetic and environmental factors. It is thus difficult to predict individual's disease outcomes and treatment options. Systems approaches including mathematical modeling can aid importantly in understanding the multifactorial liver disease etiology leading toward tailored diagnostics, prognostics and therapy. The currently established computational models of hepatic metabolism that have proven to be essential for understanding of non-alcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC) are limited to the description of gender-independent response or reflect solely the response of the males. Herein we present LiverSex, the first sex-based multi-tissue and multi-level liver metabolic computational model. The model was constructed based on in silico liver model SteatoNet and the object-oriented modeling. The crucial factor in adaptation of liver metabolism to the sex is the inclusion of estrogen and androgen receptor responses to respective hormones and the link to sex-differences in growth hormone release. The model was extensively validated on literature data and experimental data obtained from wild type C57BL/6 mice fed with regular chow and western diet. These experimental results show extensive sex-dependent changes and could not be reproduced in silico with the uniform model SteatoNet. LiverSex represents the first large-scale liver metabolic model, which allows a detailed insight into the sex-dependent complex liver pathologies, and how the genetic and environmental factors interact with the sex in disease appearance and progression. We used the model to identify the most important sex-dependent metabolic pathways, which are involved in accumulation of triglycerides representing initial steps of NAFLD. We identified PGC1A, PPARα, FXR, and LXR as regulatory factors that could become important in sex-dependent personalized treatment of NAFLD.

Nonalcoholic fatty liver disease as a sentinel marker for the development of diabetes mellitus in non-obese subjects

BACKGROUND

Non alcoholic fatty liver disease (NAFLD) is associated with substantial cardiometabolic morbidity.

AIMS

We evaluated the long-term extrahepatic complications of NAFLD and sought to evaluate NAFLD in non-obese subjects.

METHODS

A total of 2920 participants were retrospectively selected from a health check-up center in 2000, and followed through to December 2010. NAFLD was diagnosed using ultrasonography. Subjects were stratified according to body mass index, NAFLD, and metabolic syndrome.

RESULTS

The prevalence of non-obese NAFLD subjects and metabolically unhealthy non-obese subjects was 14.4% and 8.7%, respectively. In the multivariate analysis, non-obese NAFLD subjects had a significantly higher risk for diabetes mellitus (DM; HR 2.69, 95% CI 1.72-4.20, P < 0.001); no increase was observed for hypertension or cardiovascular disease. Metabolically unhealthy non-obese subjects had a significantly higher risk for hypertension (HR 2.75, 95% CI 2.02-3.74, P < 0.001), DM (HR 5.72, 95% CI 3.68-8.89, P < 0.001), and cardiovascular disease (HR 2.93, 95% CI 1.53-5.63, P = 0.001). Subgroup analysis of non-obese subjects showed that NAFLD, without metabolic syndrome, conferred a higher risk for DM (HR 3.60, 95% CI 2.03-6.39, P < 0.001).

CONCLUSION

Non-obese subjects with NAFLD are at a higher risk for DM independent of metabolic syndrome.

Clinical relevance of liver histopathology and different histological classifications of NASH in adults

Nonalcoholic fatty liver disease (NAFLD) encompasses simple steatosis and steatohepatitis (NASH) with or without fibrosis/cirrhosis and hepatocellular carcinoma. NAFLD occurs epidemically in most areas of the world, contributes to cardiovascular events and liver-related mortality and therefore exacts a major economic toll. Areas covered: Here we summarize what clinicians should know about NAFLD histopathology in adults. We report on the individual histological features and scoring systems of NAFLD: the NAFLD activity score (NAS) introduced by the NASH-Clinical Research Network, the 'Fatty Liver Inhibition of Progression' algorithm and Steatosis, Activity, and Fibrosis (SAF) score. Pros and cons of histological classifications in NASH are discussed. Special emphasis is given to liver histopathology in some high-risk patient groups, such as those with severe obesity and type 2 diabetes. Moreover, we also examine the relationship between liver histopathology and clinical features, and the impact of liver histopathology on the long-term prognosis of NAFLD. Finally, we propose an integrated diagnostic approach which utilizes both non-invasive tools and liver biopsy in those individual patients with suspected NAFLD. Expert commentary: Based on expert opinions, we conclude with a research agenda on NAFLD which focuses on the most burning topics to be addressed over the next five years.

Rho, a Fraction From Rhodiola crenulate, Ameliorates Hepatic Steatosis in Mice Models

The prevalence of non-alcoholic fatty liver disease (NAFLD), which is developed from hepatic steatosis, is increasing worldwide. However, no specific drugs for NAFLD have been approved yet. To observe the effects of Rho, a fraction from Rhodiola crenulate, on non-alcoholic hepatic steatosis, three mouse models with characteristics of NAFLD were used including high-fat diet (HFD)-induced obesity (DIO) mice, KKAy mice, and HFD combined with tetracycline stimulated Model-T mice. Hepatic lipid accumulation was determined via histopathological analysis and/or hepatic TG determination. The responses to insulin were evaluated by insulin tolerance test (ITT), glucose tolerance test (GTT), and hyperinsulinemic-euglycemic clamp, respectively. The pathways involved in hepatic lipid metabolism were observed via western-blot. Furthermore, the liver microcirculation was observed by inverted microscopy. The HPLC analysis indicated that the main components of Rho were flavan polymers. The results of histopathological analysis showed that Rho could ameliorate hepatic steatosis in DIO, KKAy, and Model-T hepatic steatosis mouse models, respectively. After Rho treatment in DIO mice, insulin resistance was improved with increasing glucose infusion rate (GIR) in hyperinsulinemic-euglycemic clamp, and decreasing areas under the blood glucose-time curve (AUC) in both ITT and GTT; the pathways involved in fatty acid uptake and de novo lipogenesis were both down-regulated, respectively. However, the pathways involved in beta-oxidation and VLDL-export on hepatic steatosis were not changed significantly. The liver microcirculation disturbances were also improved by Rho in DIO mice. These results suggest that Rho is a lead nature product for hepatic steatosis treatment. The mechanism is related to enhancing insulin sensitivity, suppressing fatty acid uptake and inhibiting de novo lipogenesis in liver.

Digital liver biopsy: Bio-imaging of fatty liver for translational and clinical research

The rapidly growing field of functional, molecular and structural bio-imaging is providing an extraordinary new opportunity to overcome the limits of invasive liver biopsy and introduce a "digital biopsy" for in vivo study of liver pathophysiology. To foster the application of bio-imaging in clinical and translational research, there is a need to standardize the methods of both acquisition and the storage of the bio-images of the liver. It can be hoped that the combination of digital, liquid and histologic liver biopsies will provide an innovative synergistic tri-dimensional approach to identifying new aetiologies, diagnostic and prognostic biomarkers and therapeutic targets for the optimization of personalized therapy of liver diseases and liver cancer. A group of experts of different disciplines (Special Interest Group for Personalized Hepatology of the Italian Association for the Study of the Liver, Institute for Biostructures and Bio-imaging of the National Research Council and Bio-banking and Biomolecular Resources Research Infrastructure) discussed criteria, methods and guidelines for facilitating the requisite application of data collection. This manuscript provides a multi-Author review of the issue with special focus on fatty liver.

A Systematic Machine Learning Based Approach for the Diagnosis of Non-Alcoholic Fatty Liver Disease Risk and Progression

Prevention and diagnosis of NAFLD is an ongoing area of interest in the healthcare community. Screening is complicated by the fact that the accuracy of noninvasive testing lacks specificity and sensitivity to make and stage the diagnosis. Currently no non-invasive ATP III criteria based prediction method is available to diagnose NAFLD risk. Firstly, the objective of this research is to develop machine learning based method in order to identify individuals at an increased risk of developing NAFLD using risk factors of ATP III clinical criteria updated in 2005 for Metabolic Syndrome (MetS). Secondly, to validate the relative ability of quantitative score defined by Italian Association for the Study of the Liver (IASF) and guideline explicitly defined for the Canadian population based on triglyceride thresholds to predict NAFLD risk. We proposed a Decision Tree based method to evaluate the risk of developing NAFLD and its progression in the Canadian population, using Electronic Medical Records (EMRs) by exploring novel risk factors for NAFLD. Our results show proposed method could potentially help physicians make more informed choices about their management of patients with NAFLD. Employing the proposed application in ordinary medical checkup is expected to lessen healthcare expenditures compared with administering additional complicated test.

Insulin resistance and hyperandrogenism drive steatosis and fibrosis risk in young females with PCOS

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) and polycystic ovary syndrome (PCOS) recognize obesity and insulin resistance (IR) as common pathogenic background. We assessed 1) whether PCOS is a risk factor for steatosis, and 2) the impact, in PCOS patients, of IR and hyperandrogenism on steatosis and fibrosis.

METHODS

We considered 202 consecutive Italian PCOS nondiabetic patients and 101 age-matched controls. PCOS was diagnosed applying the Rotterdam diagnostic criteria. Steatosis was diagnosed if hepatic steatosis index (HSI) >36, while fibrosis by using the FIB-4 score. As surrogate estimate of insulin sensitivity we considered the insulin sensitivity index (ISI). Free androgen index (FAI) was calculated as estimate of biochemical hyperandrogenism.

RESULTS

In the entire population, steatosis was observed in 68.8% of patients with PCOS, compared to 33.3 of controls (p<0.001), this association being maintained after adjusting for metabolic confounders (OR 3.73, 95% CI 1.74-8.02; P = 0.001). In PCOS patients, steatosis was independently linked to WC (OR 1.04, 95% CI 1.01-1.08; P = 0.006) and ISI Matsuda (OR 0.69, 95% CI 0.53-0.88; P = 0.004), not to free androgen index (OR 1.10, 95% CI 0.96-1.26; P = 0.14). Notably, ISI Matsuda was confirmed as independently associated with steatosis in both obese (OR 0.42, 95% CI 0.23-0.77, P = 0.005) and nonobese (OR 0.69, 95% CI 0.53-0.91, P = 0.009), patients, while FAI (OR 1.45, 95% CI 1.12-1.87; P = 0.004) emerged as an independent risk factor only in nonobese PCOS. Similarly, higher FIB-4 was independently associated with higher FAI (p = 0.02) in nonobese and with lower ISI Matsuda (p = 0.04) in obese patients.

CONCLUSIONS

We found that PCOS is an independent risk factor for steatosis, and that, IR and hyperandrogenism, this last especially in nonobese patients, are the key players of liver damage in PCOS.

Computational Modeling in Liver Surgery

The need for extended liver resection is increasing due to the growing incidence of liver tumors in aging societies. Individualized surgical planning is the key for identifying the optimal resection strategy and to minimize the risk of postoperative liver failure and tumor recurrence. Current computational tools provide virtual planning of liver resection by taking into account the spatial relationship between the tumor and the hepatic vascular trees, as well as the size of the future liver remnant. However, size and function of the liver are not necessarily equivalent. Hence, determining the future liver volume might misestimate the future liver function, especially in cases of hepatic comorbidities such as hepatic steatosis. A systems medicine approach could be applied, including biological, medical, and surgical aspects, by integrating all available anatomical and functional information of the individual patient. Such an approach holds promise for better prediction of postoperative liver function and hence improved risk assessment. This review provides an overview of mathematical models related to the liver and its function and explores their potential relevance for computational liver surgery. We first summarize key facts of hepatic anatomy, physiology, and pathology relevant for hepatic surgery, followed by a description of the computational tools currently used in liver surgical planning. Then we present selected state-of-the-art computational liver models potentially useful to support liver surgery. Finally, we discuss the main challenges that will need to be addressed when developing advanced computational planning tools in the context of liver surgery.

Clinical risk scoring for predicting non-alcoholic fatty liver disease in metabolic syndrome patients (NAFLD-MS score)

BACKGROUND & AIMS

Non-alcoholic fatty liver disease (NAFLD) can progress from simple steatosis to hepatocellular carcinoma. None of tools have been developed specifically for high-risk patients. This study aimed to develop a simple risk scoring to predict NAFLD in patients with metabolic syndrome (MetS).

METHODS

A total of 509 patients with MetS were recruited. All were diagnosed by clinicians with ultrasonography-confirmed whether they were patients with NAFLD. Patients were randomly divided into derivation (n=400) and validation (n=109) cohort. To develop the risk score, clinical risk indicators measured at the time of recruitment were built by logistic regression. Regression coefficients were transformed into item scores and added up to a total score. A risk scoring scheme was developed from clinical predictors: BMI ≥25, AST/ALT ≥1, ALT ≥40, type 2 diabetes mellitus and central obesity. The scoring scheme was applied in validation cohort to test the performance.

RESULTS

The scheme explained, by area under the receiver operating characteristic curve (AuROC), 76.8% of being NAFLD with good calibration (Hosmer-Lemeshow χ² =4.35; P=.629). The positive likelihood ratio of NAFLD in patients with low risk (scores below 3) and high risk (scores 5 and over) were 2.32 (95% CI: 1.90-2.82) and 7.77 (95% CI: 2.47-24.47) respectively. When applied in validation cohort, the score showed good performance with AuROC 76.7%, and illustrated 84%, and 100% certainty in low- and high-risk groups respectively.

CONCLUSIONS

A simple and non-invasive scoring scheme of five predictors provides good prediction indices for NAFLD in MetS patients. This scheme may help clinicians in order to take further appropriate action.

Nonalcoholic fatty liver disease: Evolving paradigms

In the last years new evidence has accumulated on nonalcoholic fatty liver disease (NAFLD) challenging the paradigms that had been holding the scene over the previous 30 years. NAFLD has such an epidemic prevalence as to make it impossible to screen general population looking for NAFLD cases. Conversely, focusing on those cohorts of individuals exposed to the highest risk of NAFLD could be a more rational approach. NAFLD, which can be diagnosed with either non-invasive strategies or through liver biopsy, is a pathogenically complex and clinically heterogeneous disease. The existence of metabolic as opposed to genetic-associated disease, notably including ”lean NAFLD” has recently been recognized. Moreover, NAFLD is a systemic condition, featuring metabolic, cardiovascular and (hepatic/extra-hepatic) cancer risk. Among the clinico-laboratory features of NAFLD we discuss hyperuricemia, insulin resistance, atherosclerosis, gallstones, psoriasis and selected endocrine derangements. NAFLD is a precursor of type 2 diabetes (T2D) and metabolic syndrome and progressive liver disease develops in T2D patients in whom the course of disease is worsened by NAFLD. Finally, lifestyle changes and drug treatment options to be implemented in the individual patient are also critically discussed. In conclusion, this review emphasizes the new concepts on clinical and pathogenic heterogeneity of NAFLD, a systemic disorder with a multifactorial pathogenesis and protean clinical manifestations. It is highly prevalent in certain cohorts of individuals who are thus potentially amenable to selective screening strategies, intensive follow-up schedules for early identification of liver-related and extrahepatic complications and in whom earlier and more aggressive treatment schedules should be carried out whenever possible.

NAFLD: Is There Anything New under the Sun?

Nonalcoholic fatty liver disease (NAFLD) is an "umbrella" definition that encompasses a spectrum of histological liver changes ranging from simple steatosis to nonalcoholic steatohepatitis (NASH) with/without fibrosis, "cryptogenic" cirrhosis, and hepatocellular carcinoma (HCC), occurring in a dysmetabolic milieu, though in the absence of excessive alcohol consumption and other competing etiologies of chronic liver disease [1].[...].

Metabolic syndrome and severity of fibrosis in nonalcoholic fatty liver disease: An age-dependent risk profiling study

BACKGROUND & AIMS

Metabolic syndrome (MS) and its individual components are associated with the severity and progression of nonalcoholic fatty liver disease (NAFLD). We sought to evaluate the relationship between MS components and the risk of severe hepatic fibrosis in NAFLD patients discriminated by age.

METHODS

We considered 863 consecutive patients with biopsy-proven NAFLD, who had been fully evaluated for components of MS.

RESULTS

Multivariate logistic regression analysis showed that F3-F4 was associated with visceral obesity, IFG/diabetes, and low high-density lipoprotein (HDL) cholesterol, but not triglycerides >150 or arterial hypertension. A significant interaction was found between age and visceral obesity (P=.04). By stratifying patients for age, we confirmed the interaction between inclusion in the third age tertile (>54 years) and visceral obesity (P=.04). In the lower (<41 years) and middle (41-54 years) age tertiles, the risk for F3-F4 fibrosis was mostly driven by visceral obesity and IFG/diabetes. This risk was higher in those with all three metabolic risk factors. Finally, among patients in the higher age tertile (>54 years), obesity did not affect the severity of fibrosis, and the risk of severe fibrosis was higher in those with low HDL and IFG/diabetes with/without visceral obesity (52%-54%).

CONCLUSIONS

Among patients with NAFLD, the metabolic profiles associated with risk for severe fibrosis varied among age groups. Low HDL, obesity and IFG/diabetes were prevalent among patients in the lower and middle age tertiles. HDL and IFG/diabetes but not visceral obesity were prevalent among those in the highest age tertile.

Insulin Resistance and NAFLD: A Dangerous Liaison beyond the Genetics

Over the last decade, the understanding of the association between insulin resistance (IR) and non-alcoholic fatty liver disease (NAFLD) has dramatically evolved. There is clear understanding that carriers of some common genetic variants, i.e., the patatin-like phospholipase domain-containing 3 (PNPLA3) or the transmembrane 6 superfamily member 2 (TM6SF2) are at risk of developing severe forms of NAFLD even in the presence of reduced or absent IR. In contrast, there are obese patients with “metabolic” (non-genetically driven) NAFLD who present severe IR. Owing to the epidemic obesity and the high prevalence of these genetic variants in the general population, the number of pediatric cases with combination of genetic and metabolic NAFLD is expected to be very high. Gut dysbiosis, excessive dietary intake of saturated fats/fructose-enriched foods and exposure to some chemicals contribute all to both IR and NAFLD, adding further complexity to the understanding of their relationship. Once NAFLD is established, IR can accelerate the progression to the more severe form of liver derangement that is the non-alcoholic steatohepatitis.

Non-alcoholic fatty liver disease: An expanded review

Non-alcoholic fatty liver disease (NAFLD) encompasses the simple steatosis to more progressive steatosis with associated hepatitis, fibrosis, cirrhosis, and in some cases hepatocellular carcinoma. NAFLD is a growing epidemic, not only in the United States, but worldwide in part due to obesity and insulin resistance leading to liver accumulation of triglycerides and free fatty acids. Numerous risk factors for the development of NAFLD have been espoused with most having some form of metabolic derangement or insulin resistance at the core of its pathophysiology. NAFLD patients are at increased risk of liver-related as well as cardiovascular mortality, and NAFLD is rapidly becoming the leading indication for liver transplantation. Liver biopsy remains the gold standard for definitive diagnosis, but the development of noninvasive advanced imaging, biochemical and genetic tests will no doubt provide future clinicians with a great deal of information and opportunity for enhanced understanding of the pathogenesis and targeted treatment. As it currently stands several medications/supplements are being used in the treatment of NAFLD; however, none seem to be the "magic bullet" in curtailing this growing problem yet. In this review we summarized the current knowledge of NAFLD epidemiology, risk factors, diagnosis, pathogenesis, pathologic changes, natural history, and treatment in order to aid in further understanding this disease and better managing NAFLD patients.

Insulin resistance promotes Lysyl Oxidase Like 2 induction and fibrosis accumulation in non-alcoholic fatty liver disease

In patients with non-alcoholic fatty liver disease (NAFLD), insulin resistance (IR) associates with fibrosis progression independently of the hepatic inflammation, but the mechanisms are still unclear. We modeled the independent contribution of inflammation (non-alcoholic steatohepatitis: NASH) by exploiting the methionine-choline deficient (MCD) diet, and that of IR by insulin receptor (InsR) haploinsufficiency (InsR+/-) in the pathogenesis of liver fibrosis in C57BL/6 mice. We confirmed the study findings in 96 patients with NAFLD. InsR+/- enhanced hepatic fat content and impaired hepatic insulin signaling leading to Forkhead box protein O1 (FoxO1) accumulation in MCD-fed mice. Remarkably, despite reduced inflammation and hampered transdifferentiation of hepatic stellate cells (HSCs), InsR+/- promoted hepatic fibrosis accumulation, which correlated with the induction of the Lysyl Oxidase Like 2 (Loxl2), involved in matrix stabilization. Loxl2 up-regulation was not a cell autonomous property of insulin resistant HSCs, but was dependent on microparticles (MPs) released specifically by insulin resistant hepatocytes (HEPs) exposed to fatty acids. The mechanism entailed FoxO1 up-regulation, as FoxO1 silencing normalized Loxl2 expression reversing fibrosis in InsR+/- MCD-fed mice. Loxl2 up-regulation was similarly detected during IR induced by obesity, but not by lipogenic stimuli (fructose feeding). Most importantly, LOXL2 up-regulation was observed in NAFLD patients with type 2 diabetes (T2D) and LOXL2 hepatic and circulating levels correlated with histological fibrosis progression. IR favors fibrosis deposition independently of the classic 'inflammation - HSC transdifferentiation' pathway. The mechanism entails a cross-talk between enhanced lipotoxicity in insulin resistant HEPs and Loxl2 production by HSCs, which was confirmed in patients with diabetes, thereby facilitating extracellular matrix (ECM) stabilization.

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.

Repurposing Pentoxifylline for the Treatment of Fibrosis: An Overview

Fibrosis is a potentially debilitating disease with high morbidity rates. It is estimated that half of all deaths that occur in the USA are attributed to fibrotic disorders. Fibrotic disorders are characterized primarily by disruption in the extracellular matrix deposition and breakdown equilibrium, leading to the accumulation of excessive amounts of extracellular matrix. Given the potentially high prevalence of fibrosis and the paucity of agents currently available for the treatment of this disease, there is an urgent need for the identification of drugs that can be utilized to treat the disease. Pentoxifylline is a methylxanthine derivative that is currently approved for the treatment of vascular diseases, in particular, claudication. Pentoxifylline has three main properties: improving the rheological properties of blood, anti-inflammatory, and antioxidative. Recently, the effectiveness of pentoxifylline in the treatment of fibrosis via attenuating and reversing fibrotic lesions has been demonstrated in several clinical trials and animal studies. As a result of the limited availability of antifibrotic agents in the long-term treatment of fibrosis that can attenuate and even reverse fibrotic lesions effectively, it would be of particular importance to consider the potential clinical utility of pentoxifylline in the treatment of fibrosis. Thus, this paper discusses the evolving roles of pentoxifylline in the treatment of different types of fibrosis.

Nonalcoholic fatty liver disease: implications for cardiovascular risk

Nonalcoholic fatty liver disease (NAFLD) is a growing epidemic in the USA affecting ∼30% of the population. It has been closely linked to metabolic syndrome and type 2 diabetes, with strong implications for cardiovascular disease (CVD). This review focuses on the relationship between NAFLD and CVD and the proposed interactions interlinking these two diseases. This appraisal also discusses treatments targeting NAFLD in the context of CVD. NAFLD is a multisystem disease and ultimately the goals of therapy are to ameliorate CVD and prevent coronary artery disease morbidity and mortality.

AISF position paper on nonalcoholic fatty liver disease (NAFLD): Updates and future directions

This review summarizes our current understanding of nonalcoholic fatty liver disease (NAFLD), a multi-factorial systemic disease resulting from a complex interaction between a specific genetic background and multiple environmental/metabolic "hits". The role of gut microbiota, lipotoxicity, inflammation and their molecular pathways is reviewed in-depth. We also discuss the epidemiology and natural history of NAFLD by pinpointing the remarkably high prevalence of NAFLD worldwide and its inherent systemic complications: hepatic (steatohepatitis, advanced fibrosis and cirrhosis), cardio-metabolic (cardiovascular disease, cardiomyopathy, arrhythmias and type 2 diabetes) and neoplastic (primary liver cancers and extra-hepatic cancers). Moreover, we critically report on the diagnostic role of non-invasive biomarkers, imaging techniques and liver biopsy, which remains the reference standard for diagnosing the disease, but cannot be proposed to all patients with suspected NAFLD. Finally, the management of NAFLD is also reviewed, by highlighting the lifestyle changes and the pharmacological options, with a focus on the innovative drugs. We conclude that the results of ongoing studies are eagerly expected to lead to introduce into the clinical arena new diagnostic and prognostic biomarkers, prevention and surveillance strategies as well as to new drugs for a tailored approach to the management of NAFLD in the individual patient.

Renin-Angiotensin System Inhibitors, Type 2 Diabetes and Fibrosis Progression: An Observational Study in Patients with Nonalcoholic Fatty Liver Disease

BACKGROUND

The clinical determinants of fibrosis progression in nonalcoholic fatty liver disease (NAFLD) are still under definition.

AIM

To assess the clinical determinants of fibrosis progression rate (FPR) in NAFLD patients with baseline and follow-up histological evaluation, with a special focus on the impact of pharmacological therapy.

METHODS

In an observational cohort of 118 Italian patients from tertiary referral centers, liver histology was evaluated according to Kleiner. Independent predictors of FPR were selected by a stepwise regression approach.

RESULTS

Median follow-up was 36 months (IQR 24-77). Twenty-five patients (18%) showed some amelioration, 63 (53%) had stability, 30 (25%) had progression of fibrosis. Patients with nonalcoholic steatohepatitis (NASH) had similar demographic and anthropometric features, but a higher prevalence of type 2 diabetes (T2D; p = 0.010), and use of renin-angiotensin axis system (RAS) inhibitors (p = 0.005). Fibrosis progression was dependent of the length of follow-up, and was associated with, but did not require, the presence of NASH (p<0.05). Both fibrosis progression and faster FPR were independently associated with higher APRI score at follow-up, absence of treatment with RAS inhibitors, and T2D diagnosis at baseline (p<0.05). There was a significant interaction between use of RAS inhibitors and T2D on FPR (p = 0.002). RAS inhibitors were associated with slower FPR in patients with (p = 0.011), but not in those without (p = NS) T2D.

CONCLUSIONS

NASH is not required for fibrosis progression in NAFLD, whereas T2D seems to drive fibrogenesis independently of hepatic inflammation. Use of RAS inhibitors may contrast fibrosis progression especially in high-risk patients affected by T2D.

Non-alcoholic fatty liver disease and dyslipidemia: An update

Non-alcoholic fatty liver (NAFLD) is the most common liver disease worldwide, progressing from simple steatosis to necroinflammation and fibrosis (leading to non-alcoholic steatohepatitis, NASH), and in some cases to cirrhosis and hepatocellular carcinoma. Inflammation, oxidative stress and insulin resistance are involved in NAFLD development and progression. NAFLD has been associated with several cardiovascular (CV) risk factors including obesity, dyslipidemia, hyperglycemia, hypertension and smoking. NAFLD is also characterized by atherogenic dyslipidemia, postprandial lipemia and high-density lipoprotein (HDL) dysfunction. Most importantly, NAFLD patients have an increased risk for both liver and CV disease (CVD) morbidity and mortality. In this narrative review, the associations between NAFLD, dyslipidemia and vascular disease in NAFLD patients are discussed. NAFLD treatment is also reviewed with a focus on lipid-lowering drugs. Finally, future perspectives in terms of both NAFLD diagnostic biomarkers and therapeutic targets are considered.

Mitochondrial Molecular Pathophysiology of Nonalcoholic Fatty Liver Disease: A Proteomics Approach

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver condition that can progress to nonalcoholic steatohepatitis, cirrhosis and cancer. It is considered an emerging health problem due to malnourishment or a high-fat diet (HFD) intake, which is observed worldwide. It is well known that the hepatocytes’ apoptosis phenomenon is one of the most important features of NAFLD. Thus, this review focuses on revealing, through a proteomics approach, the complex network of protein interactions that promote fibrosis, liver cell stress, and apoptosis. According to different types of in vitro and murine models, it has been found that oxidative/nitrative protein stress leads to mitochondrial dysfunction, which plays a major role in stimulating NAFLD damage. Human studies have revealed the importance of novel biomarkers, such as retinol-binding protein 4, lumican, transgelin 2 and hemoglobin, which have a significant role in the disease. The post-genome era has brought proteomics technology, which allows the determination of molecular pathogenesis in NAFLD. This has led to the search for biomarkers which improve early diagnosis and optimal treatment and which may effectively prevent fatal consequences such as cirrhosis or cancer.