Plasma fetuin-A is associated with endothelial dysfunction and subclinical atherosclerosis in subjects with nonalcoholic fatty liver disease

Non-obese non-alcoholic fatty liver disease and the risk of chronic kidney disease: a systematic review and meta-analysis

Background

Data on risk of developing chronic kidney disease (CKD) between non-obese and obese non-alcoholic fatty liver disease (NAFLD) patients are limited. We aimed to reveal the risk difference of incident CKD between non-obese and obese NAFLD patients.

Methods

We searched PubMed, Embase, and Web of Science databases for studies which reported the incidence of CKD in non-obese and obese NAFLD from inception to 10 March 2024. The primary and secondary outcomes were pooled. Subgroup analysis was used to examine the heterogeneity.

Results

A total of 15 studies were incorporated. The incidence of CKD in non-obese and obese NAFLD were 1,450/38,720 (3.74%) and 3,067/84,154 (3.64%), respectively. Non-obese NAFLD patients had a comparable risk of CKD as obese NAFLD (odds ratio [OR] 0.92, 95% confidence interval [95% CI] [0.72-1.19], I2 = 88%). No differences in estimated glomerular filtration rate and serum creatinine between non-obese and obese NAFLD were found. The mean differences (MD) and 95% CI were 0.01 [-0.02 to 0.04] and 0.50 [-0.90 to 1.90], respectively. In subgroup analyses, non-obese NAFLD had higher eGFR when diagnosed with ultrasound (MD 1.45, 95% CI [0.11-2.79], I2 = 21%). Non-obese NAFLD had higher creatinine in non-Asian (MD 0.06, 95% CI [0.01-0.11], I2 = 55%) and when taking BMI > 30 as the criterion for obesity (MD 0.06, 95% CI [0.00-0.12], I2 = 76%). The occurrence of CKD did not differ when non-obese NAFLD were categorized into overweight and normal-weight types.

Conclusions

Non-obese NAFLD patients experienced the same risk of CKD compared to obese NAFLD.

Vascular endothelium: The interface for multiplex signal transduction

As the innermost monolayer of the vasculature, endothelial cells (ECs) serve as the interface for multiplex signal transduction. Directly exposed to blood-borne factors, both endogenous and exogenous, ECs actively mediate vascular homeostasis and represent a therapeutic target against cardiometabolic diseases. ECs act as the first-line gateway between gut-derived substances and vasculature. Additionally, ECs convert blood flow-exerted hemodynamic forces into downstream biochemical signaling to modulate vascular pathophysiology. Besides, ECs can sense other forms of stimuli, like cell extrusion, thermal stimulation, photostimulation, radiation, magnetic field, noise, and gravity. Future efforts are still needed to deepen our understanding on endothelial biology.

Association between fatty liver index and cardiometabolic multimorbidity: evidence from the cross-sectional national health and nutrition examination survey

Background

Metabolic dysfunction associated steatotic liver disease (MASLD) contributes to the cardiometabolic diseases through multiple mechanisms. Fatty liver index (FLI) has been formulated as a non-invasive, convenient, and cost-effective approach to estimate the degree of MASLD. The current study aims to evaluate the correlation between FLI and the prevalent cardiometabolic multimorbidity (CMM), and to assess the usefulness of FLI to improve the detection of the prevalent CMM in the general population.

Methods

26,269 subjects were enrolled from the National Health and Nutrition Examination Survey 1999-2018. FLI was formulated based on triglycerides, body mass index, γ -glutamyltransferase, and waist circumference. CMM was defined as a history of 2 or more of diabetes mellitus, stroke, myocardial infarction.

Results

The prevalence of CMM was 10.84%. With adjustment of demographic, anthropometric, laboratory, and medical history covariates, each standard deviation of FLI leaded to a 58.8% risk increase for the prevalent CMM. The fourth quartile of FLI had a 2.424 times risk for the prevalent CMM than the first quartile, and a trend towards higher risk was observed. Smooth curve fitting showed that the risk for prevalent CMM increased proportionally along with the elevation of FLI. Subgroup analysis demonstrated that the correlation was robust in several conventional subpopulations. Receiver-operating characteristic curve analysis revealed an incremental value of FLI for detecting prevalent CMM when adding it to conventional cardiometabolic risk factors (Area under the curve: 0.920 vs. 0.983, P < 0.001). Results from reclassification analysis confirmed the improvement from FLI.

Conclusion

Our study demonstrated a positive, linear, and robust correlation between FLI and the prevalent CMM, and our findings implicate the potential usefulness of FLI to improve the detection of prevalent CMM in the general population.

Relationship of serum Fetuin-A with metabolic and vascular parameters in patients with prediabetes and type 2 diabetes mellitus

Background: Fetuin-A is a multifunctional liver-derived glycoprotein that is associated with insulin resistance and might play a role in the pathogenesis of prediabetes and type 2 diabetes (T2DM).

Objective: This study evaluated the relationship of Fetuin-A with metabolic and vascular parameters in patients with prediabetes and T2DM.

Materials and methods: total 120 obese patients were included. They were divided into three groups: group 1 – without carbohydrate disturbances, group 2 – with prediabetes and group 3 – with type 2 diabetes mellitus.

Results: Higher Fetuin-A serum levels were observed in patients with prediabetes and T2DM compared to those with normoglycemia. Fetuin-A ≥821 mcg/ml increased the risk for T2DM 32-fold. Additionally, we found positive correlations between Fetuin-A, vibration perception threshold and toe-brachial index and a negative correlation with neuropathy disability score.

Conclusion: Fetuin-A could be predictive for incidents of prediabetes and T2DM.

Significance of fatty liver index to detect prevalent ischemic heart disease: evidence from national health and nutrition examination survey 1999-2016

Background

Non-alcoholic fatty liver disease (NAFLD) contributes to the development of ischemic heart disease via multiple mechanisms. Fatty liver index (FLI) has been proposed as an accurate, convenient, and economic surrogate of the severity of NAFLD. Our present study aims to assess the association between FLI and the prevalent IHD and to evaluate the potential value of FLI to refine the detection of prevalent IHD in the general population.

Methods

Our work recruited 32,938 subjects from the National Health and Nutrition Examination Survey 1999-2016. IHD was diagnosed according to the subjects' self-report. FLI was determined based on triglycerides, BMI, γ-glutamyltransferase, and waist circumference.

Results

2,370 (7.20%) subjects were diagnosed with IHD. After adjustment of age, sex, race, current smoking, current drinking, PIR, BMI, WC, TC, TG, GGT, Scr, FPG, SBP, anti-hypertensive therapy, anti-diabetic therapy, and lipid-lowering therapy, one standard deviation increase of FLI resulted in a 27.0% increment of the risk of prevalent IHD. In the quartile analysis, we observed a 1.684 times risk of prevalent IHD when comparing the fourth quartile with the first quartile, and there was a trend towards higher risk across the quartiles. The smooth curve fitting displayed a linear relationship between FLI and the presence of IHD without any threshold or saturation effect. Subgroup analysis revealed a robust association in conventional cardiovascular subpopulations, and the association could be more prominent in female subjects and diabetes patients. ROC analysis demonstrated an incremental value of FLI for detecting prevalent IHD after introducing it to conventional cardiovascular risk factors (AUC: 0.823 vs. 0.859, P for comparison <0.001). Also, results from reclassification analysis implicated that more IHD patients could be correctly identified by introducing FLI into conventional cardiovascular risk factors (continuous net reclassification index: 0.633, P < 0.001; integrated discrimination index: 0.034, P < 0.001).

Conclusion

The current analysis revealed a positive and linear relationship between FLI and the prevalent IHD. Furthermore, our findings suggest the incremental value of FLI to refine the detection of prevalent IHD in the general population.

Association of nonalcoholic fatty liver disease and carotid media-intima thickness: A systematic review and a meta-analysis

Introduction

The relationship between cardiovascular disorders and nonalcoholic fatty liver disease (NAFLD) has been extensively studied. To better pool this data and make a more definite conclusion, we performed a meta-analysis to evaluate the association between NAFLD and the thickness of media and intima of carotid artery (CIMT) and cardiovascular disorders.

Methods

We searched PubMed, Ovid, Scopus, ProQuest, Web of Science, and the Cochrane Library, and analyzed the pooled data using R studio and the "metafor" package.

Results

The final analysis included a total of 59 studies with 16,179 cases and 26,120 control individuals. NAFLD was shown to be associated with an increase of 0.1231 mm (20.6%) in carotid artery intima-media thickness (CIMT) (p = 0.002, 95% confidence interval [CI]: 0.0462-0.2000) in individuals with NAFLD. The prevalence of atherosclerotic plaques in the carotid arteries and the occurrence of NAFLD are significantly correlated, according to a meta-analysis based on 17 distinct studies (p = 0.001, 1.28-1.43, 95% CI, odds ratio = 1.356).

Conclusion

Patients with increased CIMT are considerably more likely to have NAFLD. Large prospective investigations are required to corroborate these findings and their prognostic significance, along with the effectiveness of the available interventions.

Hepatic DDAH1 mitigates hepatic steatosis and insulin resistance in obese mice: Involvement of reduced S100A11 expression

Dimethylarginine dimethylaminohydrolase 1 (DDAH1) is an important regulator of plasma asymmetric dimethylarginine (ADMA) levels, which are associated with insulin resistance in patients with nonalcoholic fatty liver disease (NAFLD). To elucidate the role of hepatic DDAH1 in the pathogenesis of NAFLD, we used hepatocyte-specific Ddah1-knockout mice (Ddah1HKO) to examine the progress of high-fat diet (HFD)-induced NAFLD. Compared to diet-matched flox/flox littermates (Ddah1f/f), Ddah1HKO mice exhibited higher serum ADMA levels. After HFD feeding for 16 weeks, Ddah1HKO mice developed more severe liver steatosis and worse insulin resistance than Ddah1f/f mice. On the contrary, overexpression of DDAH1 attenuated the NAFLD-like phenotype in HFD-fed mice and ob/ob mice. RNA-seq analysis showed that DDAH1 affects NF-κB signaling, lipid metabolic processes, and immune system processes in fatty livers. Furthermore, DDAH1 reduces S100 calcium-binding protein A11 (S100A11) possibly via NF-κB, JNK and oxidative stress-dependent manner in fatty livers. Knockdown of hepatic S100a11 by an AAV8-shS100a11 vector alleviated hepatic steatosis and insulin resistance in HFD-fed Ddah1HKO mice. In summary, our results suggested that the liver DDAH1/S100A11 axis has a marked effect on liver lipid metabolism in obese mice. Strategies to increase liver DDAH1 activity or decrease S100A11 expression could be a valuable approach for NAFLD therapy.

Nonalcoholic Fatty Liver Disease and Chronic Kidney Disease Cross Talk

Nonalcoholic fatty liver disease is a multisystem condition with effects beyond the liver. The identification of chronic kidney disease as an independent mediator of nonalcoholic fatty liver disease or associated entity with shared cardiometabolic risk factors remains controversial and continues to draw scientific interest. With increasing prevalence of nonalcoholic fatty liver disease and lack of Food and Drug Administration approved therapies, these shared cardiometabolic risk factors have drawn significant attention. In this article, we review shared pathophysiological mechanisms between nonalcoholic fatty liver disease and chronic kidney disease along with current treatment strategies that might be useful for both disease processes.

The regulatory role of metabolic organ-secreted factors in the nonalcoholic fatty liver disease and cardiovascular disease

Nonalcoholic fatty liver disease (NAFLD) is a chronic metabolic disease characterized by an excessive accumulation of fat in the liver, which is becoming a major global health problem, affecting about a quarter of the population. In the past decade, mounting studies have found that 25%-40% of NAFLD patients have cardiovascular disease (CVD), and CVD is one of the leading causes of death in these subjects. However, it has not attracted enough awareness and emphasis from clinicians, and the underlying mechanisms of CVD in NAFLD patients remain unclear. Available research reveals that inflammation, insulin resistance, oxidative stress, and glucose and lipid metabolism disorders play indispensable roles in the pathogenesis of CVD in NAFLD. Notably, emerging evidence indicates that metabolic organ-secreted factors, including hepatokines, adipokines, cytokines, extracellular vesicles, and gut-derived factors, are also involved in the occurrence and development of metabolic disease and CVD. Nevertheless, few studies have focused on the role of metabolic organ-secreted factors in NAFLD and CVD. Therefore, in this review, we summarize the relationship between metabolic organ-secreted factors and NAFLD as well as CVD, which is beneficial for clinicians to comprehensive and detailed understanding of the association between both diseases and strengthen management to improve adverse cardiovascular prognosis and survival.

Crucial Regulatory Role of Organokines in Relation to Metabolic Changes in Non-Diabetic Obesity

Obesity is characterized by an excessive accumulation of fat leading to a plethora of medical complications, including coronary artery disease, hypertension, type 2 diabetes mellitus or impaired glucose tolerance and dyslipidemia. Formerly, several physiological roles of organokines, including adipokines, hepatokines, myokines and gut hormones have been described in obesity, especially in the regulation of glucose and lipid metabolism, insulin sensitivity, oxidative stress, and low-grade inflammation. The canonical effect of these biologically active peptides and proteins may serve as an intermediate regulatory level that connects the central nervous system and the endocrine, autocrine, and paracrine actions of organs responsible for metabolic and inflammatory processes. Better understanding of the function of this delicately tuned network may provide an explanation for the wide range of obesity phenotypes with remarkable inter-individual differences regarding comorbidities and therapeutic responses. The aim of this review is to demonstrate the role of organokines in the lipid and glucose metabolism focusing on the obese non-diabetic subgroup. We also discuss the latest findings about sarcopenic obesity, which has recently become one of the most relevant metabolic disturbances in the aging population.

Liver steatosis and fibrosis markers' association with cardiovascular and renal damage in Japanese adults: the TMM BirThree cohort study

INTRODUCTION AND OBJECTIVES

Patients with non-alcoholic fatty liver disease (NAFLD) are at risk for cardiovascular and chronic kidney diseases. Liver steatosis and fibrosis were assessed using the fatty liver index and fibrosis-4 index, respectively. This study aimed to examine the association between these two parameters in patients with atherosclerosis and chronic kidney disease.

MATERIALS AND METHODS

The two parameters were calculated for 11,867 adults who participated in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. Intima-media thickness and estimated glomerular filtration rate were also measured. Logistic regression models were used to estimate the odds ratios (OR).

RESULTS

Overall, 4257 (35.9%) and 4733 (39.9%) participants had a higher probability of liver steatosis and fibrosis, respectively. The adjusted OR of higher fatty liver index compared to lower fatty liver index for atherosclerosis and chronic kidney disease were 0.98 (95% confidence interval [CI], 0.77-1.24) and 1.79 (95% CI, 1.19-2.69), and those of higher FIB-4 compared to lower FIB-4 were 1.03 (95% CI, 0.82-1.30) and 0.79 (95% CI, 0.52-1.19) for atherosclerosis and chronic kidney disease, respectively.

CONCLUSIONS

A higher FLI was associated with CKD independent of other risk factors. Further research is required to identify the causal relationship between liver fat accumulation and CKD.

Endothelial Cell Dysfunction and Nonalcoholic Fatty Liver Disease (NAFLD): A Concise Review

Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases worldwide. It is strongly associated with obesity, type 2 diabetes (T2DM), and other metabolic syndrome features. Reflecting the underlying pathogenesis and the cardiometabolic disorders associated with NAFLD, the term metabolic (dysfunction)-associated fatty liver disease (MAFLD) has recently been proposed. Indeed, over the past few years, growing evidence supports a strong correlation between NAFLD and increased cardiovascular disease (CVD) risk, independent of the presence of diabetes, hypertension, and obesity. This implies that NAFLD may also be directly involved in the pathogenesis of CVD. Notably, liver sinusoidal endothelial cell (LSEC) dysfunction appears to be implicated in the progression of NAFLD via numerous mechanisms, including the regulation of the inflammatory process, hepatic stellate activation, augmented vascular resistance, and the distortion of microcirculation, resulting in the progression of NAFLD. Vice versa, the liver secretes inflammatory molecules that are considered pro-atherogenic and may contribute to vascular endothelial dysfunction, resulting in atherosclerosis and CVD. In this review, we provide current evidence supporting the role of endothelial cell dysfunction in the pathogenesis of NAFLD and NAFLD-associated atherosclerosis. Endothelial cells could thus represent a "golden target" for the development of new treatment strategies for NAFLD and its comorbid CVD.

Coagulation and Endothelial Dysfunction Associated with NAFLD: Current Status and Therapeutic Implications

Non-alcoholic fatty liver disease (NAFLD) is closely related to insulin resistance, type 2 diabetes mellitus and obesity. It is considered a multisystem disease and there is a strong association with cardiovascular disease and arterial hypertension, which interfere with changes in the coagulation system. Coagulation disorders are common in patients with hepatic impairment and are dependent on the degree of liver damage. Through a review of the literature, we consider and discuss possible disorders in the coagulation cascade and fibrinolysis, endothelial dysfunction and platelet abnormalities in patients with NAFLD.

Association between non-alcoholic fatty liver disease and subclinical atherosclerosis in Western and Asian cohorts: an updated meta-analysis

Background

Non-alcoholic fatty liver disease (NAFLD) is a well-established risk factor for cardiovascular disease, with ethnic and regional differences noted. With the recent surge of research within this field, we re-examine the evidence associating NAFLD with subclinical atherosclerosis, and investigate potential regional differences.

Methods

This is a systematic review and meta-analysis. PubMed and EMBASE were systematically searched for publications from January 1967 to July 2020 using standardised criteria. Original, observational studies investigating the association between NAFLD and either carotid intima-media thickness (CIMT) and/or coronary artery calcification (CAC) were included. Key outcomes included differences in mean CIMT, the presence of increased CIMT, the presence of CAC and the development/progression of CAC. Pooled ORs and pooled standard differences in means were calculated using random-effects models. Between-study heterogeneity was quantified using the Q statistic and I². Subgroup analyses stratified by region of study (Asian vs Western) were also conducted.

Results

64 studies involving a total of 172 385 participants (67 404 with NAFLD) were included. 44 studies assessed the effect of NAFLD on CIMT, with the presence of NAFLD associated with increased CIMT (OR 2.00, 95% CI 1.56 to 2.56). 22 studies assessed the effects of NAFLD on CAC score, with the presence of NAFLD associated with the presence of any coronary calcification (OR 1.21, 95% CI 1.12 to 1.32), and the development/progression of CAC (OR 1.26, 95% CI 1.04 to 1.52). When stratified by region, these associations remained consistent across both Asian and Western populations (p>0.05). The majority (n=39) of studies were classified as ‘high quality’, with the remaining 25 of ‘moderate quality’.

Conclusions

There is a significant positive association between various measures of subclinical atherosclerosis and NAFLD, seen across both Western and Asian populations. These results re-emphasise the importance of early risk evaluation and prophylactic intervention measures to preclude progression to clinical cardiovascular disease in patients with NAFLD.

Extent and features of liver steatosis in vitro pave the way to endothelial dysfunction without physical cell-to-cell contact

BACKGROUND AND AIMS

Several chronic multifactorial diseases originate from energy unbalance between food intake and body energy expenditure, including non-alcoholic fatty liver disease (NAFLD), diabetes, and cardiovascular disorders. Vascular endothelium plays a central role in body homeostasis, and NAFLD is often associated with endothelial dysfunction (ED), the first step in atherosclerosis. Both sugars and fatty acids (FAs) are fuel sources for energy production, but their excess leads to liver steatosis which may trigger ED through a network of mechanisms which need to be clarified. Here, we investigated the crosstalk pathways between in vitro cultured steatotic hepatocytes (FaO) and endothelial cells (HECV) being mediated by soluble factors.

METHODS AND RESULTS

We employed the conditioned medium approach to test how different extent and features of hepatic steatosis distinctively affect endothelium leading to ED. The steatogenic media collected from steatotic hepatocytes were characterized by high triglyceride content and led to lipid accumulation and fat-dependent dysfunction in HECV cells. We found a parallelism between (i) extent of hepatocyte steatosis and level of lipid accumulation in HECV cells; (ii) type of hepatocyte steatosis (with macro- or microvesicular LDs) and extent of oxidative stress, lipid peroxidation, nitric oxide release and expression of ED markers in HECV cells.

CONCLUSIONS

The present findings seem to suggest that, in addition to triglycerides, other soluble mediators should be released by steatotic hepatocytes and may influence lipid accumulation and function of HECV cells. Further studies need to depict the exact profile of soluble factors involved in steatotic hepatocyte-endothelium crosstalk.

High baseline fetuin-A levels are associated with lower atherosclerotic plaque progression as measured by 3D ultrasound

Background and aims

The glycoprotein fetuin-A has anti-inflammatory effects, increases insulin resistance and plays an important role in calcium metabolism. The aim of our study was to assess the predictive value of fetuin-A on atherosclerotic plaque progression in comparison to the established cardiovascular biomarker high sensitivity C-reactive protein (hsCRP).

Methods

In this prospective, single center-, cohort study, we included 194 patients with at least one cardiovascular risk factor or established cardiovascular disease (CVD). Over a period of 4 years, each patient underwent 3D plaque volumetry of the carotid and femoral arteries on a yearly basis. To evaluate the predictive value of biomarkers in terms of plaque progression, the baseline values of fetuin-A and hsCRP were correlated with the plaque progression from baseline to the last follow up visit.

Results

171 patients were included in the final analysis. Baseline fetuin-A levels showed a significant negative correlation with plaque progression (r = -0.244; p = 0.001). In contrast, baseline hsCRP levels showed no correlation with plaque progression (r = 0.096, p = 0.20). In the ROC-analysis, fetuin-A had a significantly better predictive value than hsCRP (fetuin-A AUC 0.67; p = 0.001 vs hsCRP AUC 0.49; p = 0.88) with an optimal cut-off value at 712 μg/ml. In patients with high fetuin A levels (>712 μg/ml), a significantly lower plaque progression was observed compared to the group with low fetuin-A levels <712 μg/ml (high fetuin-A 197 mm³ vs. low fetuin-A 279 mm³; p = 0.01).

Conclusions

Higher fetuin-A levels appear to predict lower atherosclerotic plaque progression in patients with or at risk of cardiovascular disease.

Low Levels of Serum Fetuin-A and Retinol-Binding Protein 4 Correlate with Lipoprotein Subfractions in Morbid Obese and Lean Non-Diabetic Subjects

Background: Fetuin-A and retinol-binding protein 4 (RBP4) are secreted as both hepatokine and adipokine. These are involved in insulin resistance, obesity-related dyslipidemia, and atherosclerosis. To date, correlations of circulating fetuin-A and RBP4 with lipoprotein subfractions as well as high-density lipoprotein (HDL)-linked proteins have not been entirely investigated in morbid obese and lean non-diabetic subjects. Methods: One-hundred obese non-diabetic patients (body mass index, BMI: 42.5 ± 8.1 kg/m²) along with 32 gender and age-matched normal weight controls (BMI: 24.5 ± 2.5 kg/m²) were enrolled in our study. Serum fetuin-A and RBP4 were measured by ELISA. Lipoprotein subfractions were distributed by Lipoprint gelelectrophoresis. Results: Serum fetuin-A and RBP4 were unexpectedly lower in obese patients (p < 0.01 and p < 0.01, respectively) compared to controls and correlated with each other (r = 0.37; p < 0.001). Fetuin-A had positive correlations with HDL-C (r = 0.22; p = 0.02), apolipoprotein AI (apoAI) (r = 0.33; p < 0.001), very-low density lipoprotein (VLDL) subfraction (r = 0.18; p = 0.05), and large HDL subfraction levels (r = 0.3; p = 0.001) but did not show correlation with carbohydrate parameters in all subjects. RBP4 correlated positively with HDL-C (r = 0.2; p = 0.025), apoAI (r = 0.23; p = 0.01), VLDL subfraction (r = 0.37; p < 0.001), intermediate HDL subfraction (r = 0.23; p = 0.01), and small HDL subfraction (r = 0.21; p = 0.02) concentrations, as well as C-peptide levels in overall participants. Backward stepwise multiple regression analysis showed that serum fetuin-A concentration is best predicted by RBP4 and large HDL subfraction. In model 2, VLDL subfraction was the independent predictor of serum RBP4 level. Conclusions: Our data may indicate a potential role of fetuin-A and RBP4 in impaired lipoprotein metabolism associated with obesity.

Molecular and pathobiological involvement of fetuin-A in the pathogenesis of NAFLD

The liver acts as a manufacturing unit for the production of fetuin-A, which is essential for various physiological characteristics. Scientific research has shown that a moderate upward push in fetuin-A serum levels is associated with a confirmed non-alcoholic fatty liver disease (NAFLD) diagnosis. Fetuin-A modulation is associated with a number of pathophysiological variables that cause liver problems, including insulin receptor signaling deficiencies, adipocyte dysfunction, hepatic inflammation, fibrosis, triacylglycerol production, macrophage invasion, and TLR4 activation. The focus of the present review is on the various molecular pathways, and genetic relevance of mRNA expression of fetuin-A which is correlated with progression of NAFLD. The other major area of exploration in the present review is based on the new targets for the modulation of fetuin-A, like calorie restriction and novel pharmacological agents, such as rosuvastatin, metformin, and pioglitazone which are successfully implicated in the management of various liver-related complications.

The Evolving Role of Fetuin-A in Nonalcoholic Fatty Liver Disease: An Overview from Liver to the Heart

Nonalcoholic fatty liver disease (NAFLD) is strongly associated to the features of metabolic syndrome which can progress to cirrhosis, liver failure and hepatocellular carcinoma. However, the most common cause of mortality in people with NAFLD is not liver-related but stems from atherosclerotic cardiovascular disease (CVD). The prevalence of NAFLD is on the rise, mainly as a consequence of its close association with two major worldwide epidemics, obesity and type 2 diabetes (T2D). The exact pathogenesis of NAFLD and especially the mechanisms leading to disease progression and CVD have not been completely elucidated. Human fetuin-A (alpha-2-Heremans Schmid glycoprotein), a glycoprotein produced by the liver and abundantly secreted into the circulation appears to play a role in insulin resistance, metabolic syndrome and inflammation. This review discusses the links between NAFLD and CVD by specifically focusing on fetuin-A’s function in the pathogenesis of NAFLD and atherosclerotic CVD.

Systematic Review and Meta-analysis of Circulating Fetuin-A Levels in Nonalcoholic Fatty Liver Disease

BACKGROUND AND AIMS

Accumulated studies have reported the key role of circulating fetuin-A in the development and progression of nonalcoholic fatty liver disease (NAFLD) but the results have not been consistent. In this study, we performed a systematic review and meta-analysis to explore the relationship between circulating fetuin-A level and the development and classification of NAFLD.

METHODS

The PubMed, EMBASE, and Cochrane Library databases were searched to obtain the potentially relevant studies up to May 2020. Standardized mean differences (SMD) and 95% confidence intervals of circulating fetuin-A levels were extracted and summarized. Sensitivity, subgroup analysis and meta-regression analysis were performed to investigate the potential heterogeneity. Association of circulating fetuin-A level with classification of NAFLD was also reviewed.

RESULTS

A total of 17 studies were included, composed of 1,755 NAFLD patients and 2,010 healthy controls. Meta-analysis results showed that NAFLD patients had higher circulating fetuin-A level (SMD=0.43, 95% confidence interval [CI]: 0.22-0.63, p<0.001) than controls. Subgroup analysis indicated that circulating fetuin-A level was markedly increased in adult NAFLD patients (SMD=0.48, 95% CI: 0.24-0.72, p<0.001) and not in pediatric/adolescent patients compared to controls. Circulating fetuin-A level was markedly increased in ultrasound-proven NAFLD pediatric/adolescent patients (SMD=0.42, 95% CI: 0.12-0.72, p=0.007), other than in the liver biopsy-proven NAFLD pediatric/adolescent patients. Body mass index might be the influencing factor to the heterogeneity in adult patients. Circulating fetuin-A level was not associated with the classification of NAFL vs. nonalcoholic steatohepatitis (NASH). Whether the circulating fetuin-A level was associated with the development of fibrosis remains controversial.

CONCLUSIONS

Circulating fetuin-A level was significantly higher in NAFLD patients and was not associated with the classification of NAFL vs. NASH. Whether the circulating fetuin-A level was associated with the development of fibrosis remains controversial.

Study on the correlation between urinary retinol-binding protein and nonalcoholic fatty liver disease

Background

Nonalcoholic fatty liver disease (NAFLD) affects human health worldwide. Our objective was to explore the correlation between urinary retinol-binding protein (URBP) and NAFLD.

Methods

This cross-sectional study included 445 NAFLD patients and 911 healthy controls. The URBP level and other parameters were measured.

Results

The URBP level (expressed by the RBP/creatinine ratio) was higher in the NAFLD patients compared with the non-NAFLD patients. The urinary RBP/creatinine ratio was an independent risk factor for NAFLD after univariate and multivariate regression analysis, with the or values of 2.271 (1.795-2.872, P < 0.001) and 2.338 (1.775-3.080, P < 0.001), respectively. The prevalence of the urinary RBP/creatinine ratio (groups 1, 2, 3, 4) was 20.0%, 17.3%, 27.3%, and 35.4%, respectively (P < 0.001), and the prevalence of NAFLD in the high urinary RBP/creatinine ratio group was significantly higher than that in the low urinary RBP/creatinine ratio group.

Conclusions

Our results revealed that the urinary RBP/creatinine ratio was an independent risk factor for NAFLD.

The pivotal role of heme Oxygenase-1 in reversing the pathophysiology and systemic complications of NAFLD

The pathogenesis and molecular pathways involved in non-alcoholic fatty liver disease (NAFLD) are reviewed, as well as what is known about mitochondrial dysfunction that leads to heart disease and the progression to steatohepatitis and hepatic fibrosis. We focused our discussion on the role of the antioxidant gene heme oxygenase-1 (HO-1) and its nuclear coactivator, peroxisome proliferator-activated receptor-gamma coactivator (PGC1-α) in the regulation of mitochondrial biogenesis and function and potential therapeutic benefit for cardiac disease, NAFLD as well as the pharmacological effect they have on the chronic inflammatory state of obesity. The result is increased mitochondrial function and the conversion of white adipocyte tissue to beige adipose tissue ("browning of white adipose tissue") that leads to an improvement in signaling pathways and overall liver function. Improved mitochondrial biogenesis and function is essential to preventing the progression of hepatic steatosis to NASH and cirrhosis as well as preventing cardiovascular complications.

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.

Association of Fetuin-B with Subclinical Atherosclerosis in Obese Chinese Adults

Aim: We aimed to explore the independent associations of serum Fetuin-B and common genetic variants in FETUB locus with subclinical atherosclerosis.

Methods: A cross-sectional study of 1,140 obese adults, who underwent serum Fetuin-B testing, hepatic ultrasonography scanning, genotyping on four tagging single nucleotide polymorphisms (SNPs) in FETUB locus and atherosclerosis detection, was conducted in Xiamen, China.

Results: Increasing tertiles of brachial ankle pulse wave velocity (ba-PWV) were significantly associated with higher prevalence of nonalcoholic fatty liver disease (NAFLD) (48.8%, 61.5%, and 70.5% for tertiles of 1–3, respectively, p < 0.001) and serum Fetuin-B (3.85 ± 1.39, 4.09 ± 1.40, and 4.27 ± 1.46 µg/ml, p = 0.047). Multivariable linear regression analyses with adjustment for potential confounding factors, even NAFLD per se, showed that serum Fetuin-B were significantly and positively associated with ba-PWV, with standardized regression coefficients (β) ranging from 0.055 to 0.075 (all p-values < 0.05) in different models. However, the significant relationship between serum Fetuin-B and ba-PWV disappeared with further adjustment for insulin resistance. Serum Fetuin-B was not significantly associated with ankle-brachial index (ABI). All genotypes of the four tested FETUB tagging SNPs were not significantly associated with either ba-PWV or ABI with adjustment for potential confounding factors

Conclusion: Serum Fetuin-B was positively associated with ba-PWV and may link liver fat accumulation to subclinical atherosclerosis via insulin resistance.

Metabolic Inflammation-A Role for Hepatic Inflammatory Pathways as Drivers of Comorbidities in Nonalcoholic Fatty Liver Disease?

Nonalcoholic fatty liver disease (NAFLD) is a global and growing health concern. Emerging evidence points toward metabolic inflammation as a key process in the fatty liver that contributes to multiorgan morbidity. Key extrahepatic comorbidities that are influenced by NAFLD are type 2 diabetes, cardiovascular disease, and impaired neurocognitive function. Importantly, the presence of nonalcoholic steatohepatitis and advanced hepatic fibrosis increase the risk for systemic comorbidity in NAFLD. Although the precise nature of the crosstalk between the liver and other organs has not yet been fully elucidated, there is emerging evidence that metabolic inflammation-in part, emanating from the fatty liver-is the engine that drives cellular dysfunction, cell death, and deleterious remodeling within various body tissues. This review describes several inflammatory pathways and mediators that have been implicated as links between NAFLD and type 2 diabetes, cardiovascular disease, and neurocognitive decline.

Fetuin-A and Fetuin-B in Non-Alcoholic Fatty Liver Disease: A Meta-Analysis and Meta-Regression

The magnitude of the effect of fetuin-A and fetuin-B on non-alcoholic fatty liver disease (NAFLD) remains undefined. Therefore, the aim of this study was to synthesize previous findings to obtain a reliable estimation of this relationship. This study was registered in PROSPERO with the number CRD42019126314. Studies published not later than March 2019, examining the relationship between fetuin-A, fetuin-B, and NAFLD, were identified by a systematic search in the electronic databases of the Web of Science, PubMed, Embase, and Cochrane Library. Pooled estimates of standardized mean difference (SMD), calculated using the random-effects model in a meta-analysis, were applied to estimate the strength of the association between fetuin-A, fetuin-B, and NAFLD. Thirty publications were identified and analyzed based on specified inclusion criteria. Collectively, they consisted of 3800 NAFLD participants and 3614 controls. Compared with the controls, significant higher values of the fetuin-A (SMD = 0.83, 95% CI: 0.59 to 1.07, Z = 6.82, p < 0.001) and fetuin-B (SMD = 0.18, 95% CI: 0.02 to 0.33, Z = 2.27, p = 0.023) were observed in NAFLD patients. Meanwhile, in the subgroup analysis, the effect value of fetuin-A in the NASH group was significantly higher than that in the NAFL group (p = 0.036). The findings of this study suggest that elevated fetuin-A and fetuin-B may independently indicate the occurrence of NAFLD. Nevertheless, further research is needed to confirm these results.

Paricalcitol regulatory effect on inflammatory, fibrotic and anticalcificating parameters in renal patiente. Far beyond mineral bone disease regulation

BACKWARD

Cardiovascular events are the major cause of morbidity and mortality in patients with chronic kidney disease (CKD). Inflammation and mineral-bone disorder are pathological conditions that have been associated with an increased cardiovascular risk.

OBJECTIVE

Show paricalcitol regulation overinflammatory, fibrotic and mineral disorder parameters in CKD.

MATERIAL AND METHODS

Prospective Study in 46 CKD stages III-V patients without dialysis patients whith elevated parathormone in which we introduced paricalcitol. We evaluated classic and newest mineral and bone metabolism serum parameters (calcium, phosphorus, parathormone, fibroblast growth factor-23 [FGF-23], Klotho, calcidiol), inflammatory-fibrosis and anticalcifying parameters (interleukin-6 and 10, tumor necrosis factor-a [TNF- α], transforming growth factor-b [TGF-β],bone morphogenic protein-7 [BMP-7] and fetuin-A) for four months.

RESULTS

At the end of study soluble Klotho increased (p=.001), FGF-23 remained stable, calcium and phosphorus levels were not increased, calcidiol increased (p=.010) and PTH decreased (p=.002). Inflammation-fibrosis and calcification parameters showed positive regulation after paricalcitol treatment: interleukin-6 decreased significantly (p=.001) and also TNF-α did (p=.005), on the contrary, interleukin-10 and fetuin-A increased (p=.001 for both). Anti-fibrosis marker BMP-7 increased (p=.001) and TGF-b decreased (p=.001). We did not find significant changes in renal function.

CONCLUSIONS

Paricalcitol treatment might be profitable in regulating inflammatory and anticalcificant parameters, unmodified calcium or phosphorus seric levels and preserving kidney function in renal patients with no dialysis. Our selected parameters could indicate paricalcitol effects in mineral and endothelial disorder related to renal disease.

Role of Hepatokines in Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is closely associated with metabolic diseases like type 2 diabetes and obesity. In recent decades, accumulating evidence has revealed that the hepatokines, proteins mainly secreted by the liver, play important roles in the development of NAFLD by acting directly on the lipid and glucose metabolism. As a member of organokines, the hepatokines establish the communication between the liver and the adipose, muscular tissues. In this review, we summarize the current understanding of the hepatokines and how they modulate the pathogenesis of metabolic disorders especially NAFLD.

Relationship between endothelium-dependent vasodilation and fat distribution using the new "imiomics" image analysis technique

BACKGROUND AND AIMS

We investigated how vasoreactivity in the brachial artery and the forearm resistance vessels were related to fat distribution and tissue volume, using both traditional imaging analysis and a new technique, called "Imiomics", whereby vasoreactivity was related to each of the >2M 3D image elements included in the whole-body magnetic resonance imaging (MRI).

METHODS AND RESULTS

In 326 subjects in the Prospective investigation of Obesity, Energy and Metabolism (POEM) study (all aged 50 years), endothelium-dependent vasodilation was measured by acetylcholine infusion in the brachial artery (EDV) and flow-mediated vasodilation (FMD). Fat distribution was evaluated by dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI). EDV, but not FMD, was significantly related to total fat mass, liver fat, subcutaneous (SAT) and visceral (VAT) adipose tissue in a negative fashion in women, but not in men. Using Imiomics, an inverse relationship was seen between EDV and a local tissue volume of SAT in both the upper part of the body, as well as the gluteo-femoral part and the medial parts of the legs in women. Also the size of the liver, heart and VAT was inversely related to EDV. In men, less pronounced relationships were seen. FMD was also significantly related to local tissue volume of upper-body SAT and liver fat in women, but less so in men.

CONCLUSION

EDV, and to a lesser degree also FMD, were related to liver fat, SAT and VAT in women, but less so in men. Imiomics both confirmed findings from traditional methods and resulted in new, more detailed results.

The implication of hepatokines in metabolic syndrome

Hepatokines are liver-derived proteins with equivocal roles in metabolic syndrome (MetS). These proteins have prominent role in pathogenesis of MetS component such as obesity, insulin resistance, dyslipidemia and hypertension. The identification and functional characterization of hepatokines may provide significant insights that could help in better understanding of MetS pathogenesis. Fetuin-A, Hepatocyte-derived fibrinogen-related protein 1, Fibroblast growth factor 21, Angiopoietin-related growth factor, Selenoprotein-P, Angiopoietin like proteins, Leukocyte cell-derived chemotaxin 2 are regarded as the most significant hepatokines. We describe recent data on these new hormones in progression of MetS. Understanding of the accurate role of these proteins in pathophysiology of MetS can help improving prevention and treatment of this syndrome.

Blond and blood juice supplementation in high fat diet fed mice: effect on antioxidant status and DDAH/ADMA pathway

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease spread throughout the world. The most frequent causes of death in NAFLD patients are due both to liver and cardiovascular damage. Several pathways, including the dimethylarginine dimethylaminohydrolase (DDAH)/asymmetric dimethylarginine (ADMA) pathway, are involved in the pathogenesis of NAFLD. It has been reported that ADMA plasmatic levels are increased in patients with hepatic dysfunction such as NAFLD. Although many studies demonstrated that some foods are effective in the treatment of NAFLD, few studies have evaluated their effects with respect to the prevention of the disease. It has been reported that sweet orange juice (OJ) consumption may be associated with potential health benefits. However, some varieties of sweet orange are more effective than others. The aim of the present paper was to investigate the effect of blond and blood sweet orange juice in prevention of NAFLD by evaluating its ability to improve liver steatosis in mice with diet-induced obesity, reducing oxidative stress and affecting the DDAH/ADMA pathway. Results obtained in our experimental conditions evidenced that blood orange juice rather than blond orange juice was more effective. Blood orange juice or blond orange juice enriched in anthocyanins may represent a promising dietary option for the prevention of fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease spread throughout the world.

Do Nonalcoholic Fatty Liver Disease and Fetuin-A Play Different Roles in Symptomatic Coronary Artery Disease and Peripheral Arterial Disease?

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is strongly associated with both atherosclerotic cardiovascular disease (CVD) and Fetuin-A. However, the association of Fetuin-A with atherosclerosis is more controversial. We hypothesized that the pathogenic interplay of NAFLD, Fetuin-A and atherosclerosis varies based on arterial site. Accordingly, we aimed to assess NAFLD prevalence, Fetuin-A values and their relationship with symptomatic atherosclerosis occurring in different localizations: coronary artery disease (CAD) vs. peripheral arterial disease (PAD).

METHODS

One hundred and forty-nine consecutive patients with symptomatic atherosclerotic CVD were recruited: 45 with CAD diagnosed by coronary angiography and 104 with PAD detected by doppler-ultrasound and/or computed tomography angiography and/or angiography. NAFLD was diagnosed based on both ultrasonography and exclusion of competing etiologies. Serum Fetuin-A was measured with ELISA.

RESULTS

NAFLD was detected in 54% of the overall group, with higher rates in PAD (59%) than CAD (42%) patients. Median Fetuin-A values were 256 (111-662) μg/mL, higher in patients with CAD (378 (124-662) μg/mL) than those with PAD (236 (111-461) μg/mL). The main findings were: (1) CAD patients had higher Fetuin-A values and less frequently NAFLD than PAD patients; (2) NAFLD was positively associated with Fetuin-A values; however, this association was limited to CAD patients only; (3) Fetuin-A values were positively associated with both CAD and NAFLD.

CONCLUSION

The pathogenic interplay of NAFLD, Fetuin-A and atherosclerosis probably varies according to the arterial site.

Risk of acute coronary syndrome and peripheral arterial disease in chronic liver disease and cirrhosis: A nationwide population-based study

BACKGROUND & AIMS

Until now, no study has investigated the risks of acute coronary syndrome (ACS) and peripheral arterial disease (PAD) in cirrhosis.

METHODS

In this study, 57,214 patients diagnosed with cirrhosis between 2000 and 2010 were identified from the Taiwan National Health Insurance claims data. Each patient was randomly selected and frequency-matched with an individual without cirrhosis by age, sex, and index year.

RESULTS

The overall incidence rates of ACS and PAD were 2.81 and 2.97 per 1000 person-years, respectively, in the cirrhosis cohort. The cirrhosis cohort had a higher risk of ACS [adjusted subhazard ratio (aSHR) = 1.12, 95% confidence interval (CI) = 1.03-1.22] and PAD (aSHR = 1.11, 95% CI = 1.02-1.21). The risk of ACS was highest among members of the cirrhosis cohort with ascites (aSHR = 1.09, 95% CI = 1.11-1.19).

CONCLUSIONS

Patients with chronic liver disease and cirrhosis have higher risks of ACS and PAD than those without chronic liver disease and cirrhosis.

Interaction between plasma fetuin-A and free fatty acids predicts changes in insulin sensitivity in response to long-term exercise

The hepatokine fetuin‐A can together with free fatty acids (FFAs) enhance adipose tissue (AT) inflammation and insulin resistance via toll‐like receptor 4 (TLR4). Although some of the health benefits of exercise can be explained by altered release of myokines from the skeletal muscle, it is not well documented if some of the beneficial effects of exercise can be explained by altered secretion of hepatokines. The aim of this study was to examine the effect of interaction between fetuin‐A and FFAs on insulin sensitivity after physical exercise. In this study, 26 sedentary men who underwent 12 weeks of combined endurance and strength exercise were included. Insulin sensitivity was measured using euglycemic‐hyperinsulinemic clamp, and AT insulin resistance was indicated by the product of fasting plasma concentration of FFAs and insulin. Blood samples and biopsies from skeletal muscle and subcutaneous AT were collected. Several phenotypic markers were measured, and mRNA sequencing was performed on the biopsies. AT macrophages were analyzed based on mRNA markers. The intervention improved hepatic parameters, reduced plasma fetuin‐A concentration (~11%, P < 0.01), slightly changed FFAs concentration, and improved glucose infusion rate (GIR) (~33%, P < 0.01) across all participants. The change in circulating fetuin‐A and FFAs interacted to predict some of the change in GIR (β = −42.16, P = 0.030), AT insulin resistance (β = 0.579, P = 0.003), gene expression related to TLR‐signaling in AT and AT macrophage mRNA (β = 94.10, P = 0.034) after exercise. We observed no interaction effects between FFAs concentrations and leptin and adiponectin on insulin sensitivity, or any interaction effects between Fetuin‐A and FFAs concentrations on skeletal muscle TLR‐signaling. The relationship between FFAs levels and insulin sensitivity seemed to be specific for fetuin‐A and the AT. Some of the beneficial effects of exercise on insulin sensitivity may be explained by changes in circulating fetuin‐A and FFAs, promoting less TLR4 signaling in AT perhaps by modulating AT macrophages.

Dimethylarginine Dimethylaminohydrolase 1 Protects Against High-Fat Diet-Induced Hepatic Steatosis and Insulin Resistance in Mice

AIMS

High plasma concentrations of asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, are associated with hepatic dysfunction in patients with nonalcoholic fatty liver disease (NAFLD). However, it is unknown whether ADMA is involved in the pathogenesis of NAFLD. Dimethylarginine dimethylaminohydrolase 1 (DDAH1) is an enzyme that degrades ADMA. In this study, we used Ddah1^-/- mice to investigate the effects of the ADMA/DDAH1 pathway on high-fat diet (HFD)-induced hepatic steatosis.

RESULTS

After HFD feeding for 20 weeks, Ddah1^-/- mice were more obese and had developed more severe hepatic steatosis and worse insulin resistance compared with wild-type (WT) mice. In the livers of HFD-fed mice, loss of DDAH1 resulted in higher levels of lipogenic genes, lower expression of β-oxidation genes, and greater induction of oxidative stress, endoplasmic reticulum stress, and inflammation than in the WT livers. Furthermore, ADMA treatment in HepG2 cells led to oxidative stress and steatosis, whereas overexpression of DDAH1 attenuated palmitic acid-induced steatosis, oxidative stress, and inflammation. Innovation and Conclusion: Our results provide the first direct evidence that the ADMA/DDAH1 pathway has a marked effect on hepatic lipogenesis and steatosis induced by HFD feeding. Our findings suggest that strategies to increase DDAH1 activity in hepatocytes may provide a novel approach to attenuate NAFLD development. Antioxid. Redox Signal. 26, 598-609.

Emerging Human Fetuin A Assays for Biomedical Diagnostics

Human fetuin A (HFA) plays a prominent pathophysiological role in numerous diseases and pathophysiological conditions with considerable biomedical significance; one example is the formation of calciprotein particles in osteoporosis and impaired calcium metabolisms. With impressive advances in in vitro diagnostic assays during the last decade, ELISAs have become a workhorse in routine clinical diagnostics. Recent diagnostic formats involve high-sensitivity immunoassay procedures, surface plasmon resonance, rapid immunoassay chemistries, signal enhancement, and smartphone detection. The current trend is toward fully integrated lab-on-chip platforms with smartphone readouts, enabling health-care practitioners and even patients to monitor pathological changes in biomarker levels. This review provides a critical analysis of advances made in HFA assays along with the challenges and future prospects.

Cardiovascular Risk Reduction in Patients with Nonalcoholic Fatty Liver Disease: The Potential Role of Ezetimibe

Nonalcoholic fatty liver disease (NAFLD) is widely considered to be the hepatic manifestation of the metabolic syndrome and is closely linked to dyslipidemia, obesity, and insulin resistance. Patients with NAFLD have increased mortality when compared to the general population, primarily related to cardiovascular disease or malignancy. The biologic mechanisms that link NAFLD to cardiovascular disease include expansion of visceral adipose tissue, atherogenic dyslipidemia, impaired insulin signaling, systemic inflammation, and endothelial dysfunction. Currently, there are no approved therapies for NAFLD. It has recently been hypothesized that reducing the delivery of dietary cholesterol using the hypolipidemic agent, ezetimibe, could benefit patients with NAFLD. By potently inhibiting the Niemann-Pick C1-Like 1 (NPC1L1) sterol receptor on intestinal enterocytes and within the liver, ezetimibe blocks exogenous cholesterol absorption and has been shown to improve biochemical markers of NAFLD, improve insulin sensitivity and decrease hepatic steatosis. This review summarizes the clinical and epidemiological evidence for the relationship between NAFLD and cardiovascular risk and examines the potential therapeutic role of ezetimibe.

Association between circulating inflammatory molecules and alcoholic liver disease in men

The association between alcoholic liver disease (ALD) and the inflammatory response remains controversial. The aim of this study was to explore this association between ALD and inflammation. We enrolled 214 male participants, who were divided into three age-matched groups: ALD (n = 135), chronic alcohol ingestion without ALD (non-ALD; n = 42), and control (n = 37). The BMI was significantly higher in the ALD group than in the non-ALD and control groups (all P = 0.000). Further, the constituent ratio of the liver inflammatory level was significantly higher in the ALD group than in the non-ALD and control groups (P = 0.002 and P = 0.000, respectively). In addition, the median serum ALT, AST, and GGT levels were significantly higher in the ALD group than in the control group (P = 0.023, P = 0.008, and P = 0.000, respectively); these levels were also significantly higher in the ALD group than in the non-ALD group (P = 0.013, P = 0.010, and P = 0.000, respectively). The median serum CRP level was significantly higher in the ALD group than in the non-ALD and control groups (P = 0.006 and P = 0.000, respectively). Further, the median serum TNF-α level was significantly lower in the ALD group than in the non-ALD and control groups (P = 0.004 and P = 0.000, respectively). The median serum sOX40L and HSP70 levels were significantly lower in the ALD group than in the control group (P = 0.008 and P = 0.018, respectively). In addition, the ALT, AST, and GGT levels were positively correlated with the CRP level (r = 0.211, P = 0.002; r = 0.220, P = 0.001 and r = 0.295, P = 0.000, respectively), and the GGT level was negatively correlated with the TNF-α (r = -0.225, P = 0.001), sOX40L (r = -0.165, P = 0.016), and HSP70 levels (r = -0.178, P = 0.009). Further, the Cr level was negatively correlated with the IL-10 level (r = -0.166, P = 0.015). Logistic regression analysis verified that the BMI (OR  =  1.637, 95%CI: 1.374-1.951, P  =  0.000) and GGT level were significantly higher (OR  =  1.039, 95%CI: 1.020-1.059, P  =  0.000) and that the TNF-α (OR  =  0.998, 95%CI: 0.996-1.000, P  =  0.030) and HSP70 levels were significantly lower (OR  =  1.017, 95%CI: 1.003-1.031, P  =  0.029) in the ALD group than in the non-ALD group. Further, the moderate-to-severe ALD patients had a significantly higher serum CRP level (Or =   1.349, 95%CI: 1.066-1.702, P  =  0.013) and significantly lower HSP60 (OR  =  0.965, 95%CI: 0.938-0.993, P  =  0.014) and HSP70 levels (OR  =  0.978, 95%CI: 0.962-0.995, P  =  0.010) than the mild ALD patients. These results suggest that ALD patients may present with obesity, liver damage, and an imbalanced inflammatory immune response, mainly manifesting as decreased levels of immune inflammatory cytokines. In addition, they suggest that certain liver and kidney function parameters and ALD severity are either positively or negatively correlated with certain inflammatory cytokines. Hence, ALD patients may be at increased risks of obesity- and inflammation-related diseases. Accordingly, to control the inflammatory response, preventative measures for patients with this disease should include weight control and protection of liver and kidney function.

Non-alcoholic fatty liver disease and cardiovascular risk: Pathophysiological mechanisms and implications

Non-alcoholic fatty liver disease (NAFLD) has become one of the most frequent chronic liver diseases in the Western society and its prevalence is likely to rise even further. An increasing body of evidence shows that NAFLD is not only a potentially progressive liver disease, but also has systemic consequences. More specifically, evidence points out that NAFLD has to be considered as a significant independent risk factor for subclinical and clinical cardiovascular disease (CVD). Long-term follow-up studies demonstrate cardiovascular mortality to be the most important cause of death in NAFLD patients. Moreover, ample evidence associates NAFLD with endothelial dysfunction, increased pulse wave velocity, increased coronary arterial calcifications and increased carotid intima media thickness, all established markers for CVD. Despite of all this evidence, the mechanisms by which NAFLD causally contributes to CVD are not fully elucidated. Furthermore, an extensive overview of all potential pathophysiological mechanisms and the corresponding current data are lacking. In this review we summarise current knowledge, originating from fundamental and clinical research, that mechanistically links NAFLD to CVD. Subsequently, the impact of CVD on current clinical practice and future research in the area of NALFD are discussed.

Emerging Liver-Kidney Interactions in Nonalcoholic Fatty Liver Disease

Mounting evidence connects non-alcoholic fatty liver disease (NAFLD) to chronic kidney disease (CKD). We review emerging mechanistic links between NAFLD and CKD, including altered activation of angiotensin converting enzyme (ACE)-2, nutrient/energy sensors sirtuin-1 and AMP-activated kinase, as well as impaired antioxidant defense mediated by nuclear factor erythroid 2-related factor-2 (Nrf2). Dietary fructose excess may also contribute to NAFLD and CKD. NAFLD affects renal injury through lipoprotein dysmetabolism and altered secretion of the hepatokines fibroblast growth factor-21, fetuin-A, insulin-like growth factor-1, and syndecan-1. CKD may mutually aggravate NAFLD and associated metabolic disturbances through altered intestinal barrier function and microbiota composition, the accumulation of uremic toxic metabolites, and alterations in pre-receptor glucocorticoid metabolism. We conclude by discussing the implications of these findings for the treatment of NAFLD and CKD.

Pathogenesis of nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) is a severe form of nonalcoholic fatty liver disease and a risk factor for cirrhosis and hepatocellular carcinoma. The pathological features of NASH include steatosis, hepatocyte injury, inflammation, and various degrees of fibrosis. Steatosis reflects disordered lipid metabolism. Insulin resistance and excessive fatty acid influx to the liver are two important contributing factors. Steatosis is also likely associated with lipotoxicity and cellular stresses such as oxidative stress and endoplasmic reticulum stress, which result in hepatocyte injury. Inflammation and fibrosis are frequently triggered by various signals such as proinflammatory cytokines and chemokines, released by injuried hepatocytes and activated Kupffer cells. Although much progress has been made, the pathogenesis of NASH is not fully elucidated. The purpose of this review is to discuss the current understanding of NASH pathogenesis, mainly focusing on factors contributing to steatosis, hepatocyte injury, inflammation, and fibrosis.

Implication of hepatokines in metabolic disorders and cardiovascular diseases

The liver is a central regulator of systemic energy homeostasis and has a pivotal role in glucose and lipid metabolism. Impaired gluconeogenesis and dyslipidemia are often observed in patients with nonalcoholic fatty liver disease (NAFLD). The liver is now recognized to be an endocrine organ that secretes hepatokines, which are proteins that regulate systemic metabolism and energy homeostasis. Hepatokines are known to contribute to the pathogenesis of metabolic syndrome, NAFLD, type 2 diabetes (T2DM), and cardiovascular diseases (CVDs). In this review, we focus on the roles of two major hepatokines, fetuin-A and fibroblast growth factor 21 (FGF21), as well as recently-redefined hepatokines, such as selenoprotein P, angiopoietin-like protein 4 (ANGPTL4), and leukocyte cell-derived chemotaxin 2 (LECT2). We also assess the biology and molecular mechanisms of hepatokines in the context of their potential as therapeutic targets for metabolic disorders and cardiovascular diseases.

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The roles of hepatokines such as fetuin-A, FGF21, selenoprotein P, ANGPTL4, and LECT2

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The molecular mechanisms of hepatokines in metabolic disorders and CVD

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Hepatokines as therapeutic strategies for metabolic disorders and CVD

Causes of Thickening of Carotid Intima-Media Thickness in Patients With Alcoholic Liver Disease: A Prospective Observational Study

Several studies have reported the relationship between alcoholic liver disease (ALD) and carotid intima-media thickness (CIMT). Few studies, however, have investigated the causes of CIMT thickening in patients with ALD. The authors explored the causes of CIMT thickening in patients with ALD. The authors enrolled 152 patients who were stratified into groups: nonthickening CIMT with ALD (group A); thickening CIMT with ALD (group B); nonthickening CIMT without ALD (group C); and thickening CIMT without ALD (group D). The CIMT was significantly different between patients with and without ALD (χ 2= 3.875, P = 0.049). The patients in groups A, B, and C were significantly younger than group D (P = 0.001, 0.036, and 0.001, respectively). The body mass indexes (BMI) in groups A and B were significantly higher than in group C (P = 0.000 and 0.007, respectively). The blood glucose levels in groups B and D were significantly higher than in group C (P = 0.016 and 0.018, respectively). The blood uric acid levels in group B were significantly higher than in groups A, C, and D (P = 0.009, 0.000, and 0.003, respectively). The blood uric acid in group A was significantly higher than in group C (P = 0.002). The serum total cholesterol (TC) levels of patients in group B were significantly higher than in groups A and C (P = 0.027 and 0.000, respectively) and the serum TC level in group A was significantly higher than in group C (P = 0.048). The serum triglyceride (TG) levels in groups A and B were significantly higher than in group C (P = 0.027 and 0.000, respectively). The serum of very low-density lipoprotein (VLDL) levels in group B were significantly higher than in group C (P = 0.000). Although a comparison of the low-density lipoprotein (LDL) and high-density lipoprotein (HDL) serum levels among the 4 groups indicated no changes. The serum LDL levels in group B were significantly higher than in group A (P = 0.008). No significant differences were observed among the groups with respect to serum homocysteine, C-reactive protein (CRP), interleukin-6 (IL-6), malondialdehyde (MDA), superoxide dismutase (SOD), soluble OX40 ligand (sOX40L), or heat shock protein (HSP) 60 or 70. Alcoholic liver disease may result in CIMT thickening. Carotid intima-media thickness is associated with age and metabolic factors in patients with ALD. In addition, ALD might promote the premature occurrence of CIMT thickening. The thickening of carotid artery intima thickness, however, is not associated with cytokine profiles, oxidative balance, or immune responses in patients with ALD.

Cardiovascular risk across the histological spectrum and the clinical manifestations of non-alcoholic fatty liver disease: An update

Non-alcoholic fatty liver disease (NAFLD) is considered to be an independent cardiovascular disease (CVD) risk factor. However, simple steatosis has a benign clinical course without excess mortality. In contrast, the advanced form of NAFLD, non-alcoholic steatohepatitis (NASH) with liver fibrosis increases mortality by approximately 70%, due to an increase in CVD mortality by approximately 300%. Chronic kidney disease (CKD) may be caused by NAFLD/NASH and it substantially increases CVD risk, especially in the presence of type 2 diabetes mellitus. Moreover, CKD may trigger NAFLD/NASH deterioration in a vicious cycle. NAFLD/NASH is also related to increased arterial stiffness (AS), an independent CVD risk factor that further raises CVD risk. Diagnosis of advanced liver fibrosis (mainly by simple non-invasive tests), CKD, and increased AS should be made early in the course of NAFLD and treated appropriately. Lifestyle measures and statin treatment may help resolve NAFLD/NASH and beneficially affect the CVD risk factors mentioned above.

Relationship of fibroblast growth factor 23 and fetuin--A to coronary atherosclerosis

BACKGROUND

Serum fibroblast growth factor 23 (FGF-23) and fetuin-A are established predictors of morbidity and mortality due to cardiovascular disease. The objective of the present study is to evaluate the relationship between coronary artery disease (CAD) and serum concentrations of FGF-23 and fetuin-A.

METHODS

A total of 383 subjects who underwent coronary computed tomography angiography (CCTA) were included in the study. CCTA detected CAD in 208 patients; the rest of the patients had no detectable CAD.

RESULTS

Serum FGF-23 and fetuin-A levels were significantly increased in CAD patients compared to non-CAD patients (26.6±21.1pg/mL vs. 17.9±16.1pg/mL, p=0.001 and 826±350mg/L vs. 595±300mg/L, p<0.001, respectively). Serum FGF-23, fetuin-A, low-density lipoprotein (LDL)-cholesterol, and uric acid values were elevated in non-diabetic patients with CAD when compared to those without CAD. FGF-23, and fetuin-A were not significantly different in diabetic patients with CAD when compared to those without CAD. Using multivariate logistic regression analysis, we found that age, hypertension, LDL-Cholesterol, high-density lipoprotein (HDL)-Cholesterol, hs-CRP, uric acid, FGF-23 and fetuin-A levels were independently associated with the presence of CAD.

CONCLUSION

FGF-23 and fetuin-A were positively correlated with coronary atherosclerosis Similar trends were seen among diabetic patients, but this did not reach statistical significance. FGF-23 and fetuin-A could be used as novel risk markers of cardiovascular disease.