Fatty liver without a large “belly”: Magnified review of non-alcoholic fatty liver disease in non-obese patients

Evaluation of MACK-3 parameters, metabolic and fibrotic characteristics of non-alcoholic fatty liver disease patients with hypertension

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is an inflammatory subtype of non-alcoholic fatty liver disease (NAFLD) and recent non-invasive test, MACK-3, demonstrated good diagnostic characteristics for fibrosis in several studies. The aim of our study was to assess the liver state using the non-invasive MACK-3 Test, and its link with liver fibrosis stage, inflammatory activity, steatosis, and metabolic markers in NAFLD patients with hypertension (HT).

METHODS

Thirty adult NAFLD patients with HT, aged 30 to 60 years (mean age 46.36±5.1 years) were included in our study. The control group consisted of 20 healthy volunteers. In addition to basic laboratory tests and ultrasonographic examination, validated non-invasive fibrosis test were performed. MACK-3 was calculated using the online calculator with the following variables: fasting glucose, fasting insulin, aspartate aminotransferase (AST) and cytokeratin 18 (CK18).

RESULTS

All NAFLD patients with HT were characterized with increased liver enzymatic activity, lipid profile, increased levels of insulin and HOMA-IR˂0.001. MACK-3 parameters were positively correlated with thymol test = 0.45 (P<0.013), with aspartataminotransferase (AST) = 0.38 (P<0.03) and alanineaminotransferase (ALT) - =0.38 (P<0.03), with the stage of Fibrotest activity = 0.25 (P<0.018) and steatosis = 0.76 (P<0.001).

CONCLUSIONS

MACK-3 parameters associations with hepatic enzymatic activity, steatosis and activity stage suggest this test as a promising for screening use in such patients and requires further studies.

Is it possible to treat nonalcoholic liver disease using a flavanol-based nutraceutical approach? Basic and clinical data

Nonalcoholic fatty liver disease (NAFLD) is characterized by a spectrum of diseases, ranging from simple steatosis to hepatocellular carcinoma. The main factors for NAFLD are closely related to obesity, insulin resistance, intestinal microbiota alterations, hyperinsulinism, low-grade systemic inflammation, nitroxidative stress, lipid peroxidation, and mitochondrial dysfunction. Currently, the treatment of NAFLD is based on diet and exercise because, to date, there is no specific pharmacological agent, already approved, that raises the need for new therapeutic strategies. Nutraceuticals, such as polyphenols, have potential beneficial effects for health. In this article, the beneficial effects of epigallocatechin-3-gallate (EGCG) and (-)-epicatechin (EC) are discussed. EGCG is the main catechin in green tea, which has shown in various studies its potential effect preventing and treating NAFLD since it has shown antihyperlipidemic, anti-inflammatory, antifibrotic, antioxidant, and improvement of liver lipid metabolism. However, it has been found that excessive consumption may cause hepatotoxicity. EC is widely distributed in nature (fruits and vegetables). This flavanol has shown many beneficial effects, including antihypertensive, anti-inflammatory, anti-hyperglycemic, antithrombotic, and antifibrotic properties. It increases mitochondrial biogenesis, and it also has effects on the regulation of synthesis and metabolism of lipids. This flavanol is a nontoxic substance; it has been classified by the United States Food and Drug Administration as harmless. The EC-induced effects can be useful for the prevention and/or treatment of NAFLD.

Triglyceride affects the association between estimated glomerular filtration rate and the onset of non-alcoholic fatty liver disease: A second analysis of a Chinese cohort study

Objective

The role of triglyceride (TG) and estimated glomerular filtration rate (eGFR) effect modifiers on the risk of non-alcoholic fatty liver disease (NAFLD) is unknown. This study examined whether TG modifies the relationship between eGFR and incident NAFLD.

Methods

In a Chinese hospital from January 2010 to December 2014, 15,555 non-obese subjects were collected systematically for this retrospective cohort study. The target-independent and dependent variables were eGFR measured at baseline and NAFLD appearing during follow-up. The modified variable was TG measured at baseline. The multivariate Cox proportional hazards model was used to explore eGFR and TG’s association with NAFLD risk. We explored a priori interaction between eGFR and TG, and performed subgroup analyses to further assess whether the relationship between eGFR and incident NAFLD was modified by TG. We also explored the effect of TG and eGFR interaction on the risk of NAFLD.

Results

The mean age was 43.09 ± 14.92 years, and 8,131 (52.27%) were males. During a median follow-up time of 35.8 months, 2,077 (13.35%) individuals developed NAFLD. In the adjusted model, eGFR was negatively associated with incident NAFLD (HR = 0.984, 95% CI: 0.982, 0.987), while TG was positively related to NAFLD (HR = 1.582, 95% CI: 1.490, 1.681). TG could modify the relationship between eGFR and incident NAFLD. A stronger association between eGFR and NAFLD could be found in the participants without hypertriglyceridemia (HTG) (HR = 0.981, 95% CI: 0.978–0.984, P for interaction = 0.0139). In contrast, the weaker association was probed in the population with HTG (HR = 0.986, 95% CI: 0.983–0.989). At the same time, we also found an interaction between eGFR and TG in influencing NAFLD risk. In participants with decreased eGFR and HTG, the risk of NAFLD was significantly increased. Further, compared to non-HTG subjects with eGFR ≥ 116.56 ml/min/1.73 m², participants with HTG and eGFR < 82.88 ml/min/1.73 m² had about a fourfold increase in the risk (HR = 4.852 95% CI: 3.943–5.970) of NAFLD.

Conclusion

eGFR and TG is independently associated with NAFLD risk. The association of eGFR with incident NAFLD is likely to be modified by TG in the Chinese non-obese population. There was an interactive effect between eGFR and TG in affecting NAFLD risk. In participants with decreased eGFR and hypertriglyceridemia, the risk of NAFLD is significantly increased.

Predictive markers of nonalcoholic fatty liver disease in lean patients. A multinomial regression model and a 2k factorial analysis

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) is associated with obesity and insulin resistance; however, there is a group of non-obese patients with NAFLD that need to be characterized. Our aim was to evaluate the factors associated with NAFLD in non-obese subjects in a third-level hospital.

METHODS

A comparative cross-sectional study was performed. Participants were divided into four groups: non-obese without NAFLD (group 1), non-obese with NAFLD (group 2), obese without NAFLD (group 3), and obese with NAFLD (group 4). We evaluated the effect of clinical and biochemical characteristics with the disease by groups using a multinomial regression model and a 2K factorial analysis.

RESULTS

We included 278 participants. Low platelet-lymphocyte ratio (PLR) as a novel parameter associated with NAFLD in non-obese subjects. Age, uric acid, alanine transaminase (ALT), high-density lipoprotein (HDL)-cholesterol, and neutrophil-lymphocyte ratio (NLR) were other related parameters (akaike information criterion = 557). NLR had the larger OR in groups with NAFLD (lean with NAFLD 7.12, obese with NAFLD 13.02). The 2k factorial design found inverse effect on PLR by NAFLD (effect -21.89, P < 0.001), which was higher than BMI (effect -1.33, P < 0.045).

CONCLUSION

Our study found that PLR is a novel parameter with inverse correlation with NAFLD in non-obese patients. Other related parameters are age, hyperuricemia, elevation of ALT and NLR, and low HDL-cholesterol.

A systematic review and meta-analysis of serum resistin level and its relation to HOMA-IR score using meta-regression in nonalcoholic fatty liver disease patients

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) comorbidity with adipose tissue dysfunction is not new and studies have focused on how adipose tissue influences NAFLD pathophysiology. OBJECTIVE: Quantification of nature and magnitude of the association between serum resistin and also insulin resistance, by calculating pooled Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) score, with NAFLD pathophysiology was the objective of the current study. METHODS: Using systematic review and meta-analysis and standardized mean difference (SMD) as the effect size, the levels of resistin and HOMA-IR scores have been investigated in NAFLD subjects in comparison with controls in the case-control studies using random-effects models. RESULTS: This meta-analysis retrieved a total number of 665 and 522 cases and 671 and 555 control subjects until May 2020 for serum levels of resistin and HOMA-IR score until May 2020. The final analyses demonstrated that pooled SMD of resistin and HOMA-IR score was 0.687 (95% confidence interval, 0.070–1.304) and 1.368 (95% confidence interval, 1.080–1.655); respectively. Moreover, the p-value for the test of significance for each pooled SMD was examined by the z-test and calculated as 0.029 and 0.000 for resistin and HOMA-IR score (clearly considered as statistically significant). CONCLUSION: Based on the findings, the HOMA-IR score and the serum levels of resistin in NAFLD subjects are associated with disease pathogenesis.

Diagnosis and management of fatty liver

Globally, the prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing rapidly and constitutes a significant healthcare burden due to associated complications including hepatic (cirrhosis and hepatocellular cancer) and non-hepatic (cardiovascular deaths) disorders. It is closely linked to insulin resistance and metabolic syndrome but moderate alcohol consumption frequently coexists. Recently, genetic polymorphisms were implicated in the development of non-obese NAFLD. Apart from liver biopsy, in order to assess for steatosis, fibrosis and non-alcoholic steatohepatitis (NASH), advances in non-invasive serum tests and elastography have provided similarly accurate, more accessible and safer alternatives for risk stratification. As for treatment in 2020, weight loss and lifestyle modification remain the central strategy. Unfortunately, no pharmacological agents have been approved thus far, but there are a number of potential therapies in the pipeline for fibrosis and NASH. Treatment of underlying metabolic disorders is important. While the term NAFLD was coined in the 1980s, more recent understanding may support a change in nomenclature highlighting its strong metabolic roots.

Early cardiac electrical and structural changes in patients with non-obese non-alcoholic fatty liver disease

Background    Obese non-alcoholic fatty liver disease (NAFLD) was found to increase the risk of developing atrial fibrillation (AF) regardless of the metabolic syndrome subgroups that may accompany it. In this study, the effect of NAFLD on the structural and electrical functions of the heart was investigated using tissue Doppler echocardiography (TDE) in non-obese NAFLD patients without any known risk factors for AF.Material and methods    The study included 43 female patients (31.3±3.8 years), who had stage 2-3 hepatosteatosis detected by liver ultrasonography and diagnosed as non-obese NAFLD (patient group), and 31 healthy women (control group, 32.5±3.6 years). In addition to standard echocardiographic parameters, inter- and intra-atrial electromechanical delay (EMD) were evaluated by TDE.Results    Interatrial EMD (PA lateral - PA tricuspid) and intraatrial EMD (PA septum - PA tricuspid) were significantly longer in patient group (16.1±3.4 vs. 12.5±2.3 ms, p&lt;0.001, and 8.4±1.6 vs. 6.6±1.6 ms, p&lt;0.001, respectively). At the subclinical level. atrial size, left ventricular diastolic function, and left ventricular wall thickness measurements were greater in the patient group.Conclusion    Inter-atrial and intra-atrial EMD were detected in young women with non-obese NAFLD. In addition, at the subclinical level, structural and functional impairment was detected However, large-volume prospective studies are required to cobfirm these findings regarding the development of AF in non-obese NAFLD patients.

A Nomogram Model Based on Noninvasive Bioindicators to Predict 3-Year Risk of Nonalcoholic Fatty Liver in Nonobese Mainland Chinese: A Prospective Cohort Study

The purpose of this study is to establish and validate an accurate and personalized nonalcoholic fatty liver disease (NAFLD) prediction model based on the nonobese population in China. This study is a secondary analysis of a prospective study. We included 6,155 nonobese adults without NAFLD at baseline, with a median follow-up of 2.3 years. Univariate and multivariate Cox regression analyses were used to determine independent predictors. The least absolute shrinkage and selection operator (LASSO) regression analysis was used to optimize the selection of variables. Based on the results of multivariate analysis, a prediction model was established. Harrell's consistency index (C-index) and area under the curve (AUC) were used to determine the discrimination of the proposed model. The goodness of fit of the calibration model was tested, and the clinical application value of the model was evaluated by decision curve analysis (DCA). The participants were randomly divided into a training cohort (n = 4,605) and a validation cohort (n = 1,550). Finally, seven of the variables (HDL-c, BMI, GGT, ALT, TB, DBIL, and TG) were included in the prediction model. In the training cohort, the C-index and AUC value of this prediction model were 0.832 (95% confidence interval (CI), 0.820-0.844) and 0.861 (95% CI, 0.849-0.873), respectively. In the validation cohort, the C-index and AUC values of this prediction model were 0.829 (95% CI, 0.806-0.852) and 0.859 (95% CI, 0.841-0.877), respectively. The calibration plots demonstrated good agreement between the estimated probability and the actual observation. DCA demonstrated a clinically effective predictive model. Our nomogram can be used as a simple, reasonable, economical, and widely used tool to predict the 3-year risk of NAFLD in nonobese populations in China, which is helpful for timely intervention and reducing the incidence of NAFLD.

Association between high fatty liver index and development of colorectal cancer: a nationwide cohort study with 21,592,374 Korean

BACKGROUND/AIMS

In Korea, the incidence of colorectal cancer (CRC) and nonalcoholic fatty liver disease (NAFLD) has increased due to a westernized lifestyle. This study investigated whether a high fatty liver index that reflects NAFLD correlates with CRC.

METHODS

Data from the National Health Insurance Corporation 2009 to 2012 were analyzed. NAFLD disease was defined as a fatty liver index > 60 in the absence of alcohol consumption of ≥ 30 g/day.

RESULTS

NAFLD was identified in 2,543,649 (11.8%) of 21,592,374 participants. CRC was identified in 19,785 (0.8%) of participants with NAFLD (fatty liver index ≥ 60) and in 80,871 (0.6%) participants without NAFLD (fatty liver index < 30). Multivariate logistic regression analysis demonstrated an independent association between NAFLD and CRC after adjusting for other confounders (hazard ratio, 1.13; odds ratio, 1.12 to 1.15). In subgroup analyses, fatty liver index ≥ 60 was associated with CRC regardless of body mass index, but the association was more prominent in persons with a normal index. NAFLD, in the absence of diabetes, hypertension, or dyslipidemia, was more highly associated with CRC than when one or more of these conditions are present.

CONCLUSION

CRC should be considered as a possibility in patients with fatty liver index ≥ 60, even in the absence of obesity or other metabolic syndromes.

Rescue of Hepatic Phospholipid Remodeling Defectin iPLA2β-Null Mice Attenuates Obese but Not Non-Obese Fatty Liver

Polymorphisms of group VIA calcium-independent phospholipase A2 (iPLA₂β or PLA2G6) are positively associated with adiposity, blood lipids, and Type-2 diabetes. The ubiquitously expressed iPLA₂β catalyzes the hydrolysis of phospholipids (PLs) to generate a fatty acid and a lysoPL. We studied the role of iPLA₂β on PL metabolism in non-alcoholic fatty liver disease (NAFLD). By using global deletion iPLA₂β-null mice, we investigated three NAFLD mouse models; genetic Ob/Ob and long-term high-fat-diet (HFD) feeding (representing obese NAFLD) as well as feeding with methionine- and choline-deficient (MCD) diet (representing non-obese NAFLD). A decrease of hepatic PLs containing monounsaturated- and polyunsaturated fatty acids and a decrease of the ratio between PLs and cholesterol esters were observed in all three NAFLD models. iPLA₂β deficiency rescued these decreases in obese, but not in non-obese, NAFLD models. iPLA₂β deficiency elicited protection against fatty liver and obesity in the order of Ob/Ob › HFD » MCD. Liver inflammation was not protected in HFD NAFLD, and that liver fibrosis was even exaggerated in non-obese MCD model. Thus, the rescue of hepatic PL remodeling defect observed in iPLA₂β-null mice was critical for the protection against NAFLD and obesity. However, iPLA₂β deletion in specific cell types such as macrophages may render liver inflammation and fibrosis, independent of steatosis protection.

A Novel Combination of Fruits and Vegetables Prevents Diet-Induced Hepatic Steatosis and Metabolic Dysfunction in Mice

BACKGROUND

Epidemiological studies suggest that higher fruits and vegetables (F&V) consumption correlates with reduced risk of hepatic steatosis, yet evidence for causality and the underlying mechanisms is lacking.

OBJECTIVES

We aimed to determine the causal relation between F&V consumption and improved metabolic disorders in mice fed high-fat (HF) (Experiment-1) or normal-fat (Experiment-2) diets and its underlying mechanisms.

METHODS

Six-week-old male C57BL/6J mice were randomly grouped and fed diets supplemented at 0%-15% (wt:wt) with a freeze-dried powder composed of 24 commonly consumed F&V (human equivalent of 0-9 servings/d) for 20 wk. In Experiment-1, mice were fed an HF (45% kcal fat) diet with 0% (HF0), 5%, 10%, or 15% (HF15) F&V or a matched low-fat control diet (10% kcal fat). In Experiment-2, mice were fed an AIN-93 diet (basal) (B, 16% kcal fat) with 0% (B0), 5%, 10%, or 15% (B15) F&V supplementation. Body weight and composition, food intake, hepatic steatosis, inflammation, ceramide levels, sphingomyelinase activity, and gut microbiota were assessed.

RESULTS

In Experiment-1, mice fed the HF15 diet had lower weight gain (17.9%), hepatic steatosis (48.4%), adipose tissue inflammation, blood (24.6%) and liver (33.9%) ceramide concentrations, and sphingomyelinase activity (38.8%) than HF0 mice (P < 0.05 for all). In Experiment-2, mice fed the B15 diet had no significant changes in weight gain but showed less hepatic steatosis (28.5%), blood and adipose tissue inflammation, and lower blood (30.0%) ceramide concentrations than B0 mice (P < 0.05 for all). These F&V effects were associated with favorable microbiota changes.

CONCLUSIONS

These findings represent the first evidence for a causal role of high F&V intake in mitigating hepatic steatosis in mice. These beneficial effects may be mediated through changes in ceramide and/or gut microbiota, and suggest that higher than currently recommended servings of F&V may be needed to achieve maximum health benefits.

Decrease in waist-to-hip ratio reduced the development of chronic kidney disease in non-obese non-alcoholic fatty liver disease

To date, there are few studies that have evaluated the prognostic impact of changes in abdominal obesity or weight on long-term adverse kidney outcomes in non-alcoholic fatty liver disease (NAFLD). We investigated the effect of changes in waist-to-hip ratio (WHR) and body weight (BW) on chronic kidney disease (CKD) development, especially in non-obese NAFLD patients. We included 6,137 participants from a community-based prospective cohort with 12-year follow-up in Korea. NAFLD patients were categorized according to time-averaged percent changes in WHR and BW (≤−5%, >−5% to <5%, and ≥5%). Compared to non-obese controls, non-obese NAFLD was significantly associated with an increased risk of incident CKD (hazard ratio [HR] = 1.238, 95% confidence interval [CI] = 1.006–1.524). In 1,563 NAFLD patients, compared to patients with minimal changes in WHR (>−5% to <5%), patients with a decreased WHR (≤−5%) had a significantly attenuated risk of CKD development (HR = 0.300; 95% CI = 0.194–0.464). Furthermore, risk reduction from decreased WHR for developing CKD remained significant in non-obese NAFLD patients (HR = 0.290; 95% CI = 0.114–0.736). In conclusion, a decrease in WHR of more than 5% significantly reduced the risk of CKD development in NAFLD patients, even in those who were non-obese. Thus, serial monitoring of WHR may be prioritized in the management of NAFLD.

Non-Alcoholic Fatty Liver Disease in Non-Obese Individuals: Prevalence, Pathogenesis and Treatment

Non-alcoholic fatty liver disease (NAFLD) parallels comorbidities such as metabolic syndrome, dyslipidaemia or diabetes. Although NAFLD is very prevalent in overweight-obese individuals (i.e. body mass index ≥25 kg/m2), recent studies point to the presence of NAFLD in non-obese individuals, for both the Asian (<25 kg/m2) and Caucasian (<30 kg/m2) populations. This paper discusses the pathogenic pathways and current treatment options of NAFLD in non-obese populations. In this respect, non-obese subjects also need to undergo the medical screening for NAFLD. Across the scientific community, we aim to promote the advancement of knowledge in this emerging field.

Real-world comorbidities and treatment patterns among patients with non-alcoholic fatty liver disease receiving phosphatidylcholine as adjunctive therapy in Russia

Objective

Previous research conducted in Russia showed that the number of patients with non-alcoholic fatty liver disease (NAFLD) and associated metabolic comorbidities is large. We conducted an observational study to describe the management of NAFLD in patients with metabolic syndrome in Russia.

Design

A total of 2843 adult patients from 174 medical sites across 6 federal districts of Russia with newly diagnosed NAFLD, who had at least one of four comorbidities, namely overweight/obesity, hypertension, type 2 diabetes mellitus, and hypercholesterolaemia, and who received phosphatidylcholine (PPC) as an adjunctive treatment to standard care, were enrolled during 2015-2016.

Results

Overall, 2263 patients (79.6%) had at least two metabolic comorbidities associated with NAFLD; overweight/obesity was the most common comorbidity reported in 2298 patients (80.8%). Simple steatosis was the most frequently identified clinical form of NAFLD, diagnosed in 2128 patients (74.9%). Among hypertensive patients, ACE inhibitors, statins, and sartans were most commonly prescribed. Biguanides were administered in more than half of diabetic patients. In patients with overweight/obesity and hypercholesterolaemia, statins were the most frequently prescribed medications. Almost all patients (2837/2843; 99.8%) were treated with 1.8 g of PPC three times per day. PPC therapy was associated with a 90.5% 6-month compliance rate, high treatment satisfaction, and a favourable safety profile. However, almost 15% of diabetic patients and 40% of overweight/obese patients received no further treatment.

Conclusions

In Russia, patients with newly diagnosed NAFLD represent a population heavily burdened by comorbidities, mainly overweight/obesity and hypercholesterolaemia. A significant part of these patients did not receive a comprehensive pharmacotherapy, highlighting the existing unmet need in the current management of NAFLD patients with metabolic syndrome in Russia.

Hypoxic Signaling and Cholesterol Lipotoxicity in Fatty Liver Disease Progression

Cholesterol is the only lipid whose absorption in the gastrointestinal tract is limited by gate-keeping transporters and efflux mechanisms, preventing its rapid absorption and accumulation in the liver and blood vessels. In this review, I explored the current data regarding cholesterol accumulation in liver cells and key mechanisms in cholesterol-induced fatty liver disease associated with the activation of deleterious hypoxic and nitric oxide signal transduction pathways. Although nonalcoholic fatty liver disease (NAFLD) affects both obese and nonobese individuals, the mechanism of NAFLD progression in lean individuals with healthy metabolism is puzzling. Lean NAFLD individuals exhibit normal metabolic responses, implying that liver damage is not associated with impaired metabolism per se and that direct lipotoxic effects are crucial for disease progression. Several redox and oxidant signaling pathways involving cholesterol are at play in fatty liver disease development. These include impairment of the mitochondrial and lysosomal function by cholesterol loading of the inner-cell membranes; formation of cholesterol crystals and hepatocyte degradation; and crown-like structures surrounding degrading hepatocytes, activating Kupffer cells, and evoking inflammation. The current review focuses on the induction of liver inflammation, fibrosis, and steatosis by free cholesterol via the hypoxia-inducible factor 1α (HIF-1α), a main oxygen-sensing transcription factor involved in all stages of NAFLD. Cholesterol loading in hepatocytes can result in chronic HIF-1α activity because of the decreased oxygen availability and excessive production of nitric oxide and mitochondrial reactive oxygen species.