Relationship between non-alcoholic fatty liver disease and coronary heart disease

Associations between metabolic dysfunction-associated fatty liver disease and atherosclerotic cardiovascular disease

Non-alcoholic fatty liver disease (NAFLD) is closely related to metabolic syndrome and remains a major global health burden. The increased prevalence of obesity and type 2 diabetes mellitus (T2DM) worldwide has contributed to the rising incidence of NAFLD. It is widely believed that atherosclerotic cardiovascular disease (ASCVD) is associated with NAFLD. In the past decade, the clinical implications of NAFLD have gone beyond liver-related morbidity and mortality, with a majority of patient deaths attributed to malignancy, coronary heart disease (CHD), and other cardiovascular (CVD) complications. To better define fatty liver disease associated with metabolic disorders, experts proposed a new term in 2020 - metabolic dysfunction associated with fatty liver disease (MAFLD). Along with this new designation, updated diagnostic criteria were introduced, resulting in some differentiation between NAFLD and MAFLD patient populations, although there is overlap. The aim of this review is to explore the relationship between MAFLD and ASCVD based on the new definitions and diagnostic criteria, while briefly discussing potential mechanisms underlying cardiovascular disease in patients with MAFLD.

Genetic and Lifestyle Risk Factors of Metabolic Dysfunction-Associated Fatty Liver Disease and Its Relationship with Premature Coronary Artery Disease: A Study on the Pars Cohort

BACKGROUND

The main objective of this study is to identify the risk factors of metabolic dysfunction-associated fatty liver disease (MAFLD) in coronary artery disease (CAD) patients.

METHODS

The present retrospective cohort study is part of the Pars Cohort Study (PCS). The participants were categorized as having MAFLD or not. The pattern of independent variables in patients was compared with those who did not have MAFLD. All variables were retained in the multivariable logistic regression model.

RESULTS

Totally, 1862 participants with CAD were enrolled in this study. MAFLD was diagnosed in 647 (40.1%) participants. Gender, diabetes, hypertension, tobacco, opium, alcohol, age, weight, waist circumference, cholesterol, HDL, triglyceride, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were significantly different in MAFLD and non-MAFLD patients. Also, the results of multivariable logistic regression show male gender (OR=0.651, 95% CI: 0.470‒0.902, P value=0.01) and opium consumption (OR=0.563, 95% CI: 0.328‒0.968, P value<0.001) to be negative risk factors of MAFLD occurrence in CAD patients. Having diabetes (OR=2.414, 95% CI: 1.740-3.349, P value<0.001), high waist circumference (OR=1.078, 95% CI: 1.055‒1.102, P value<0.01), high triglyceride (OR=1.005, 95% CI: 1.001‒1.008, P value=0.006), and high ALT (OR=1.039, 95% CI: 1.026‒1.051, P value<0.01) were positive risk factors of MAFLD in CAD patients.

CONCLUSION

Our study found that consuming opium decreases the likelihood of MAFLD in CAD patients, since these patients have decreased appetite and lower body mass index (BMI). On the other hand, female gender, having diabetes, high waist circumference, high triglyceride levels, and high ALT levels increase the probability of MAFLD in CAD patients.

Liver stiffness as a cornerstone in heart disease risk assessment

Metabolic dysfunction-associated steatotic liver disease (MASLD) typically presents with hepatic fibrosis in advanced disease, resulting in increased liver stiffness. A subset of patients further develops liver cirrhosis and hepatocellular carcinoma. Cardiovascular disease is a common comorbidity in patients with MASLD and its prevalence is increasing in parallel. Recent evidence suggests that especially liver stiffness, whether or not existing against a background of MASLD, is associated with heart diseases. We conducted a narrative review on the role of liver stiffness in the prediction of highly prevalent heart diseases including heart failure, cardiac arrhythmias (in particular atrial fibrillation), coronary heart disease, and aortic valve sclerosis. Research papers were retrieved from major scientific databases (PubMed, Web of Science) until September 2023 using 'liver stiffness' and 'liver fibrosis' as keywords along with the latter cardiac conditions. Increased liver stiffness, determined by vibration-controlled transient elastography or hepatic fibrosis as predicted by biomarker panels, are associated with a variety of cardiovascular diseases, including heart failure, atrial fibrillation, and coronary heart disease. Elevated liver stiffness in patients with metabolic liver disease should lead to considerations of cardiac workup including N-terminal pro-B-type natriuretic peptide/B-type natriuretic peptide determination, electrocardiography, and coronary computed tomography angiography. In addition, patients with MASLD would benefit from heart disease case-finding strategies in which liver stiffness measurements can play a key role. In conclusion, increased liver stiffness should be a trigger to consider a cardiac workup in metabolically compromised patients.

Clinical Management of Non-alcoholic Steatohepatitis and the Role of the Cardiologist

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of fat-associated liver conditions that increase risk of cardiovascular disease and mortality. The diagnosis and clinical management of NAFLD remain a challenge for cardiologists. Our group performed a systematic review in PubMed of the relationship between NAFLD and cardiovascular disease, identifying 35 relevant articles. NAFLD is likely to be the liver's expression of metabolic syndrome and increases the risk of several cardiovascular diseases, including coronary artery disease, stroke, heart failure and electrical disorders, and chronic kidney disease. Echocardiography is a useful tool to check early subclinical abnormalities in heart structure and function linked to NAFLD progression, such as cardiac diastolic impairment or epicardial fat thickness. Currently, NAFLD is predominantly managed by lifestyle changes with the aim of weight loss, based on the Mediterranean diet and intense exercise training. Despite the lack of approved drugs for NAFLD, new potential treatments, mainly glucagon-like peptide-1 agonists or sodium-glucose cotransporter 2 inhibitors, could change cardiologists' approach to this pathology.

Effects of gut microbial therapy on lipid profile in individuals with non-alcoholic fatty liver disease: an umbrella meta-analysis study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD), the most common liver disease, is closely associated with metabolic conditions such as obesity and diabetes mellitus, which significantly impact human health outcomes. The impaired lipid profiles observed in NAFLD individuals can further contribute to cardiovascular events. Despite the high prevalence of NAFLD, there is currently no confirmed intervention approved for its treatment. This study aimed to summarize the results of meta-analysis studies of randomized control trials assessing the impact of gut microbial therapy (probiotics, synbiotics, and prebiotics) on the lipid profile of individuals with NAFLD.

METHODS

A systematic search was conducted on PubMed, Scopus, Web of Science, and Cochrane Library up to November 1, 2022. Meta-analyses surveying the impact of microbial therapy on lipid profile parameters (triglyceride (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and total cholesterol (TC)) in the NAFLD population were included in our umbrella review. The final effect size (ES) was estimated, and sensitivity and subgroup analyses were performed to explore heterogeneity.

RESULTS

Fifteen studies were included in this umbrella review. Microbial therapy significantly reduced TG (ES - 0.31, 95% CI - 0.51, - 0.11, P < 0.01), TC (ES - 1.04, 95% CI - 1.46, - 0.61, P < 0.01), and LDL (ES - 0.77, 95% CI - 1.15, - 0.39, P < 0.01) in individuals with NAFLD. However, the effect on HDL was not statistically significant (ES - 0.06; 95% CI - 0.19, 0.07, P = 0.39).

CONCLUSION

Considering the absence of approved treatments for NAFLD and the promising role of microbial therapies in improving the three lipid profiles components in individuals with NAFLD, the use of these agents as alternative treatment options could be recommended. The findings underscore the potential of gut microbial therapy, including probiotics, synbiotics, and prebiotics, in managing NAFLD and its associated metabolic complications.

TRIAL REGISTRATION

PROSPERO ( CRD42022346998 ).

The Identification and Clinical Value Evaluation of CYCS Related to Asthma through Bioinformatics Analysis and Functional Experiments

Background

Asthma is one of the most common respiratory diseases and one of the largest burdens of health care resources across the world. This study is aimed at using bioinformatics methods to find effective clinical indicators for asthma and conducting experimental validation.

Methods

We downloaded GSE64913 data and performed differentially expressed gene (DEG) screening. Weighted gene coexpression network analysis (WGCNA) on DEGs was applied to identify key module most associated with asthma for protein-protein interaction (PPI) analysis. According to the degree value, ten genes were obtained and subjected to expression analysis and receiver operating characteristic (ROC) analysis. Next, key genes were screened for expression analysis and immunological analysis. Finally, cell counting kit-8 (CCK-8) and qRT-PCR were also conducted to observe the influence of hub gene on cell proliferation and inflammatory cytokines.

Results

From the GSE64913 dataset, 711 upregulated and 684 downregulated DEGs were found. In WGCNA, the top 10 genes in the key module were examined by expression analysis in asthma, and CYCS was determined as an asthma-related oncogene with a good predictive ability for the prognosis of asthmatic patients. CYCS is significantly associated with immune cells, such as HHLA2, IDO1, TGFBR1, and CCL18 and promoted the proliferation of asthmatic cells in vitro.

Conclusion

CYCS plays an oncogenic role in the pathophysiology of asthma, indicating that this gene may become a novel diagnostic biomarker and promising target of asthma treatment.

Exercise increases myocardial free fatty acid oxidation in subjects with metabolic dysfunction-associated fatty liver disease

BACKGROUND AND AIMS

Metabolic dysfunction-associated fatty liver disease (MAFLD) is associated with dyslipidemia and may promote cardiac lipotoxicity. Myocardial free fatty acids (FFA) oxidation (MO_FFA) is normal in pre-diabetes, but reduced in heart failure. We hypothesized that during exercise MO_FFA, very low-density lipoprotein triglycerides (VLDL-TG) secretion, hepatic FFA utilization, and lactate production differ among obese subjects with and without MAFLD.

METHODS

Nine obese subjects with MAFLD and 8 matched subjects without MAFLD (Control) without a history of heart failure and cardiovascular disease were compared before and after 90-min exercise at 50% Peak oxygen consumption. Basal and exercise induced cardiac and hepatic FFA oxidation, uptake and re-esterification and VLDL-TG secretion were measured using [¹¹C]palmitate positron-emission tomography and [1-¹⁴C]VLDL-TG.

RESULTS

In the heart, increased MO_FFA was observed after exercise in MAFLD, whereas MO_FFA decreased in Control (basal vs exercise, MAFLD: 4.1 (0.8) vs 4.8 (0.8) μmol·100 ml^-1 min^-1; Control: 4.9 (1.8) vs 4.0 (1.1); μmol·100 ml^-1 min^-1, mean (SD), p < 0.048). Hepatic FFA fluxes were significantly lower in MAFLD than Control and increased ≈ two-fold in both groups. VLDL-TG secretion was 50% greater in MAFLD at rest and similarly suppressed during exercise. Plasma lactate increased significantly less in MAFLD than Control during exercise.

CONCLUSIONS

Using robust tracer-techniques we found that obese subjects with MAFLD do not downregulate MO_FFA during exercise compared to Control, possibly due to diminished lactate supply. Hepatic FFA fluxes are significantly lower in MAFLD than Control, but increase similarly with exercise. VLDL-TG export remains greater in MAFLD compared to Control. Basal and post-exercise myocardial and hepatic FFA, VLDL-TG and lactate metabolism is abnormal in subjects with MAFLD compared to Control.

LncRNA ZFAS1 ameliorates injury led by non-alcoholic fatty liver disease via suppressing lipid peroxidation and inflammation

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is known to aggravate metabolic disturbance and increase the risk of complications. The purpose of the present study was to explore the mechanism underlying the clinical effects of ZFAS1 on NAFLD.

METHODS

Expression of the ZFAS1 RNA was quantified in patients with NAFLD through reverse transcription-quantitative polymerase chain reaction. The correlations were assessed using Pearson's correlation coefficient test. The receiver operating characteristic curve was used to evaluate the identification of ZFAS1. Commercial kits were purchased to detect the pertinent parameters to establish mice models. Luciferase report assay was used to identify and confirm the presence of ZFAS1 ceRNA.

RESULTS

The increase of ZFAS1 expression in patients with NAFLD was noted and the high expression level may be considered a risk factor for NAFLD. In mouse models fed with high-fat diet (HFD), the expression levels of ZFAS1 were increased; furthermore, sh-ZFAS1 reversed ZFAS1 overexpression. HFD administration resulted in liver injury, which was indicated by increased lipid deposition, aggressive oxidative stress, and imbalanced inflammatory reaction. However, sh-ZFAS1 attenuated the abovementioned adverse effects of HFD. MiR-144-5p was a ceRNA of ZFAS1; in addition, the expression of miR-144-5p was reduced in HFD-managed models and patients with NAFLD. ZFAS1 could successfully regulate the expression levels of miR-144-5p. In the present study, the negative relationship between ZFAS1 and miR-144-5p was documented.

CONCLUSION

Excessive expression of ZFAS1 and its diagnostic potential was noted in patients with NAFLD. It was evident that ZFAS1 may be responsible for exacerbating the worsening of liver function.

FIB-4 Index and Neutrophil-to-Lymphocyte-Ratio as Death Predictor in Coronary Artery Disease Patients

Nonalcoholic fatty liver disease (NAFLD)-associated liver fibrosis is likely related to coronary artery disease (CAD) by the mediation of systemic inflammation. This study aimed at evaluating the predictive value of neutrophil-to-lymphocyte-ratio (NLR) and fibrosis-4 index (FIB-4), indices of inflammation and fibrosis, respectively, on CAD mortality. Data from 1460 CAD patients (1151 males, age: 68 ± 10 years, mean ± SD) were retrospectively analyzed. Over a median follow-up of 26 months (interquartile range (IQR) 12−45), 94 deaths were recorded. Kaplan−Meier survival analysis revealed worse outcomes in patients with elevation of one or both biomarkers (FIB-4 > 3.25 or/and NLR > 2.04, log-rank p-value < 0.001). In multivariate Cox regression analysis, the elevation of one biomarker (NLR or FIB-4) still confers a significant independent risk for mortality (hazard ratio (HR) = 1.7, 95% confidence interval (95% CI): 1.1−2.7, p = 0.023), whereas an increase in both biomarkers confers a risk corresponding to HR = 3.5 (95% CI: 1.6−7.8, p = 0.002). Categorization of patients with elevated FIB-4/NLR could provide valuable information for risk stratification and reduction of residual risk in CAD patients.

A Meta-Analysis on the Global Prevalence, Risk factors and Screening of Coronary Heart Disease in Nonalcoholic Fatty Liver Disease

BACKGROUND & AIMS

Cardiovascular disease remains the leading cause of death in patients with nonalcoholic fatty liver disease (NAFLD). Studies examining the association of coronary heart disease (CHD) and NAFLD are cofounded by various cardiometabolic factors, particularly diabetes and body mass index. Hence, we seek to explore such association by investigating the global prevalence, independent risk factors, and influence of steatosis grade on manifestation of CHD among patients with NAFLD.

METHODS

Two databases, Embase and Medline, were utilized to search for articles relating to NAFLD and CHD. Data including, but not limited to, continent, diagnostic methods, baseline characteristics, prevalence of CHD, CHD severity, NAFLD severity, and risk factors were extracted.

RESULTS

Of the 38 articles included, 14 reported prevalence of clinical coronary artery disease (CAD) and 24 subclinical CAD. The pooled prevalence of CHD was 44.6% (95% confidence interval [CI], 36.0%-53.6%) among 67,070 patients with NAFLD with an odds ratio of 1.33 (95% CI, 1.21%-1.45%; P &lt; .0001). The prevalence of CHD was higher in patients with moderate to severe steatosis (37.5%; 95% CI, 15.0%-67.2%) than those with mild steatosis (29.6%; 95% CI, 13.1%-54.0%). The pooled prevalence of subclinical and clinical CAD was 38.7% (95% CI, 29.8%-48.5%) and 55.4% (95% CI, 39.6%-70.1%), respectively.

CONCLUSION

Steatosis was found to be related with CHD involvement, with moderate to severe steatosis related to clinical CAD. Early screening and prompt intervention for CHD in NAFLD are warranted for holistic care in NAFLD.

New Insights into Non-Alcoholic Fatty Liver Disease and Coronary Artery Disease: The Liver-Heart Axis

Non-alcoholic fatty liver disease (NAFLD) represents the hepatic expression of the metabolic syndrome and is the most prevalent liver disease. NAFLD is associated with liver-related and extrahepatic morbi-mortality. Among extrahepatic complications, cardiovascular disease (CVD) is the primary cause of mortality in patients with NAFLD. The most frequent clinical expression of CVD is the coronary artery disease (CAD). Epidemiological data support a link between CAD and NAFLD, underlain by pathogenic factors, such as the exacerbation of insulin resistance, genetic phenotype, oxidative stress, atherogenic dyslipidemia, pro-inflammatory mediators, and gut microbiota. A thorough assessment of cardiovascular risk and identification of all forms of CVD, especially CAD, are needed in all patients with NAFLD regardless of their metabolic status. Therefore, this narrative review aims to examine the available data on CAD seen in patients with NAFLD, to outline the main directions undertaken by the CVD risk assessment and the multiple putative underlying mechanisms implicated in the relationship between CAD and NAFLD, and to raise awareness about this underestimated association between two major, frequent and severe diseases.

Effects of serum branched-chain amino acids on nonalcoholic fatty liver disease and subsequent cardiovascular disease

BACKGROUND

To reveal the role of branched-chain amino acids (BCAAs) in the development and progression of nonalcoholic fatty liver disease (NAFLD) and the effect on the incidence of subsequent cardiovascular disease.

METHODS

A total of 1302 subjects in the cohort study of the Huai'an Diabetes Prevention Program were divided into two groups according to whether NAFLD was present at baseline. The group without NAFLD at baseline was only followed up, and the group with NAFLD at baseline received diet and exercise interventions. Anthropometric and biochemical examinations were performed at baseline and at the end of 4 years for all subjects. Serum BCAA (leucine, isoleucine, and valine) levels were measured by hydrophilic interaction chromatography-tandem mass spectrometry. The associations of baseline serum BCAA levels with the risk for NAFLD, coronary heart disease (CHD), and cardiovascular events (CVEs) after 4 years were further evaluated.

RESULTS

(1) At baseline and after the 4-year follow-up, baseline serum leucine, valine, and total BCAAs in the NAFLD group were significantly higher than those in the non-NAFLD group (p < 0.05). (2) According to whether NAFLD was present at baseline and after follow-up, all subjects were divided into four groups, including the control group, new case group, improvement group, and unchanged group. There was no significant difference in baseline BCAAs levels between the new case group and the improvement group (p > 0.05). (3) Risk factors for the occurrence and development of NAFLD were analysed by a multiple logistic regression model according to whether NAFLD existed at baseline. Serum leucine (OR = 1.058, 95% CI 1.005-1.114, p = 0.033) and total BCAAs (OR = 1.023, 95% CI 1.001-1.046, p = 0.045) were independent risk factors for new-onset NAFLD. Serum valine (OR = 1.131, 95% CI 1.043-1.226, p = 0.003), and total BCAAs (OR = 1.040, 95% CI 1.003-1.078, p = 0.035) were independent risk factors showing that NAFLD could not be reversed. (4) The cross-table Chi-square test showed that the incidence of both CHD and CVEs was significantly highest in the new case group (p < 0.05). (5) After adjusting for confounding factors, baseline isoleucine, valine, and BCAA levels were independently associated with new-onset CHD in subjects with or without NAFLD at baseline (p < 0.05).

CONCLUSIONS

High BCAA levels exacerbate the risk of CHD and CVEs by influencing the occurrence and progression of NAFLD. However, lifestyle interventions could reverse the risk of NAFLD, CHD and CVEs associated with BCAAs.

Association between the LRP5 rs556442 gene polymorphism and the risks of NAFLD and CHD in a Chinese Han population

Background

Multiple studies have demonstrated the involvement of low-density lipoprotein receptor-related protein 5 (LRP5) in metabolism-related diseases. This study explored the relationship between the LRP5 rs556442 gene polymorphism and the risks of non-alcoholic fatty liver disease (NAFLD) and coronary heart disease (CHD) in a Chinese Han population.

Methods

This retrospective case–control study included 247 patients with NAFLD, 200 patients with CHD, 118 patients with both NAFLD and CHD, and 339 healthy controls from June 2018 to June 2019 at Qingdao Municipal Hospital. Basic information and clinical characteristics were collected for all subjects. The genotype and allele frequency of LRP5 rs556442 were determined.

Results

The genotype distributions of LRP5 rs556442 differed significantly between the CHD and NAFLD + CHD groups (P < 0.05). The LRP5 rs556442 GG genotype markedly promoted the risk of NAFLD in CHD patients [odds ratio (OR) = 2.857, 95% confidence interval (CI): 1.196–6.824, P = 0.018). After adjustment for sex, age, and body mass index (BMI), this association remained significant (OR = 3.252, 95% CI: 1.306–8.102, P = 0.011). In addition, the LRP5 rs556442 AA + AG genotype was associated with an increased BMI in obese NAFLD patients (OR = 1.526, 95% CI: 1.004–2.319, P = 0.048). However, after adjustment for sex and age, this association was no longer significant (OR = 1.504, 95% CI: 0.991–2.282, P = 0.055).

Conclusions

This study found that the LRP5 rs556442 GG genotype increased the risk of NAFLD in CHD patients and AA + AG genotype may be associated with an increased BMI in obese NAFLD patients among a Chinese Han population.

Trial registration ChiCTR, ChiCTR1800015426. Registered 28 March 2018—Retrospectively registered, http://www.chictr.org.cn/showproj.aspx?proj=26239.

Association between Non-alcoholic Fatty Liver Disease and the Severity of Coronary Artery Stenosis in Eastern Chinese Population

Background: The present study aimed to investigate the relationship of non-alcoholic fatty liver disease (NAFLD) with the severity and extent of coronary stenotic lesions calculated by the Gensini score. In addition, the ability of Fibrosis-4 (FIB4) score to differentiate coronary artery calcification (CAC) and its severity is assessed. Methods: The current retrospective study was performed on a total of 342 patients examined between January and December 2016 in an affiliated hospital of Jiaxing University, Zhejiang, China. The study used liver ultrasonography for the assessment of NAFLD. Furthermore, the FIB4 and Gensini scores were used to predict hepatic fibrosis risk and the severity of coronary stenotic lesions. Results: The present study revealed that the serum levels of triglycerides, fasting glucose, alanine aminotransferase, and uric acid were significantly higher in patients with NAFLD than in participants without NAFLD (P < 0.001, P < 0.001, P = 0.032, and P = 0.002). Moreover, cases with NAFLD had a higher percentage of diabetes mellitus and hypertension (P < 0.001 and 0.001) than those without NAFLD. It was noted that the level of high-density lipoprotein was lower in patients with NAFLD than in participants without NAFLD (P = 0.006). In addition, we observed that the Gensini score was higher in patients with NAFLD than in participants without NAFLD (P = 0.033). It was found that 27.3%, 25.8%, 45.7%, and 56.3% of the participants had NAFLD in control, single, double, and multi lesion groups, respectively, and the difference was statistically significant (P = 0.008). The number of diseased vessels in patients with severe NAFLD was higher than in the control group (P < 0.001). It was also evident that the number of affected vessels significantly increased (P = 0.010 and P = 0.001) with the stages of NAFLD predicted by the FIB4 and Gensini scores. Furthermore, the Gensini score in patients with moderate and severe NAFLD was higher than in the control group (P = 0.013 and P = 0.019). We also conducted univariate logistic regression analyses to examine the relationship of CAC with FIB4 scores, and it was not significant (P = 0.191). Conclusions: The present study showed a positive relationship between NAFLD severity and coronary stenotic lesions in the eastern Chinese population. Furthermore, it was found that the higher the degree of FIB4 score, the higher the risk of CAC in patients with NAFLD. Therefore, assessing NAFLD severity using the FIB4 score may be useful for differentiating the patients at a higher risk of CAC. However, further prospective studies are required to establish the link between the FIB4 score and CAC.

Non-alcoholic fatty liver disease as an independent factor of cardiometabolic risk of cardiovascular diseases

Non-alcoholic fatty liver disease (NAFLD) is a pressing public health problem affecting up to a third of the world's adult population. The main reasons for its high mortality rate are cardiovascular diseases. They are caused by subclinical atherosclerosis characteristic of NAFLD, venous thromboembolic complications, functional and structural myocardial disorders, calcification of heart valves, heart rhythm and conduction disturbances. At the same time, NAFLD can serve as an independent factor of the cardiometabolic risk of their development, which is associated with atherogenic dyslipidemia, as well as the release of numerous pro-inflammatory mediators both from the pathologically altered liver and as a result of systemic endotoxemia, which is the result of disturbance of the intestinal microbiota, accompanied by a decrease in intestinal microbial gene richness., a change in its composition and function, followed by bacterial translocation. Considering that most patients with NAFLD die from cardiovascular complications, it becomes obvious that exclusively “liver-oriented” principles of their treatment cannot be sufficient, but require a multidisciplinary team approach involving cardiologists, cardiac surgeons and doctors of other related specialties.

The potential pathophysiological role of altered lipid metabolism and electronegative low-density lipoprotein (LDL) in non-alcoholic fatty liver disease and cardiovascular diseases

Non-alcoholic fatty liver disease (NAFLD) is an umbrella term for a range of conditions caused by a build-up of fat in the liver. It is usually seen in people who are overweight or obese. Increasingly common around the world, this disease is the most common chronic liver disease in the United States, affecting about a quarter of the population. Recently, the designation of NAFLD as 'metabolic dysfunction-associated fatty liver disease' (MAFLD) has been a subject of current debate. In this context, 'insulin resistance' is the underlying common and basic pathophysiological mechanism of metabolic dysfunction due to its association with obesity, type 2 diabetes mellitus (T2DM), metabolic syndrome, dyslipidemia and NAFLD. All these pathological conditions are among the metabolic risk factors for cardiovascular diseases, too. Also, due to the bidirectional causality between NAFLD and cardiovascular diseases, a liver-heart axis is suggested. Therefore, various factors such as insulin resistance as well as systemic inflammation, cytokines, oxidative stress, adipokines, hepatokines, genes and intestinal microbiota have been identified as possible pathogenic factors that play a role in the explanation of the complex NAFLD and cardiovascular risk relationship. Recent data and cumulative evidence show that electronegative low-density lipoprotein [LDL (-)/L5] cholesterol is a promising biomarker for complex organ interactions and diseases associated with liver-heart axis. In this mini review, we focus not only on recent data on NAFLD mechanisms, but also on the potential of the lipid mediator LDL (-)/L5 as a diagnostic and therapeutic target for liver-heart line diseases.

Sex Differences in Nonalcoholic Fatty Liver Disease: Estrogen Influence on the Liver-Adipose Tissue Crosstalk

Significance: Nonalcoholic fatty liver disease (NAFLD) is a hepatic and systemic disorder with a complex multifactorial pathogenesis. Owing to the rising incidence of obesity and diabetes mellitus, the prevalence of NAFLD and its impact on global health care are expected to increase in the future. Differences in NAFLD exist between males and females, and among females depending on their reproductive status. Clinical and preclinical data show that females in the fertile age are more protected against NAFLD, and studies in postmenopausal women and ovariectomized animal models support a protective role for estrogens. Recent Advances: An efficient crosstalk between the liver and adipose tissue is necessary to regulate lipid and glucose metabolism, protecting the liver from steatosis and insulin resistance contributing to NALFD. New advances in the knowledge of sexual dimorphism in liver and adipose tissue are providing interesting clues about the sex differences in NAFLD pathogenesis that could inspire new therapeutic strategies. Critical Issues: Sex hormones influence key master regulators of lipid metabolism and oxidative stress in liver and adipose tissue. All these sex-biased metabolic adjustments shape the crosstalk between liver and adipose tissue, contributing to the higher protection of females to NAFLD. Future Directions: The development of novel drugs based on the protective action of estrogens, but without its feminizing or undesired side effects, might provide new therapeutic strategies for the management of NAFLD. Antioxid. Redox Signal. 35, 753-774.

Lysophosphatidylcholine promotes intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression in human umbilical vein endothelial cells via an orphan G protein receptor 2-mediated signaling pathway

The oxLDL-based bioactive lipid lysophosphatidylcholine (LPC) is a key regulator of physiological processes including endothelial cell adhesion marker expression. This study explored the relationship between LPC and the human umbilical vein endothelial cell expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) with a particular focus on the regulation of the LPC-G2A-ICAM-1/VCAM-1 pathway in this context. We explored the LPC-inducible role of orphan G protein receptor 2 (G2A) in associated regulatory processes by using human kidney epithelial (HEK293) cells that had been transfected with pET-G2A, human umbilical vein endothelial cells (HUVECs) in which an shRNA was used to knock down G2A, and western blotting and qPCR assays that were used to confirm changes in gene expression. For in vivo studies, a rabbit model of atherosclerosis was established, with serum biochemistry and histological staining approaches being used to assess pathological outcomes in these animals. The treatment of both HEK293 cells and HUVECs with LPC promoted ICAM-1 and VCAM-1 upregulation, while incubation at a pH of 6.8 suppressed such LPC-induced adhesion marker expression. Knocking down G2A by shRNA and inhibiting NF-κB activity yielded opposite outcomes. The application of a Gi protein inhibitor had no impact on LPC-induced ICAM-1/VCAM-1 expression. Atherosclerotic model exhibited high circulating LDL and LPC levels as well as high aortic wall ICAM-1/VCAM-1 expression. Overall, these results suggested that the LPC-G2A-ICAM-1/VCAM-1 pathway may contribute to the atherogenic activity of oxLDL, with NF-κB antagonists representing potentially viable therapeutic tools for the treatment of cardiovascular disease.

Interplay between Heart Disease and Metabolic Steatosis: A Contemporary Perspective

The liver-heart axis is a growing field of interest owing to rising evidence of complex bidirectional interplay between the two organs. Recent data suggest non-alcoholic fatty liver disease (NAFLD) has a significant, independent association with a wide spectrum of structural and functional cardiac diseases, and seems to worsen cardiovascular disease (CVD) prognosis. Conversely, the effect of cardiac disease on NAFLD is not well studied and data are mostly limited to cardiogenic liver disease. We believe it is important to further investigate the heart-liver relationship because of the tremendous global health and economic burden the two diseases pose, and the impact of such investigations on clinical decision making and management guidelines for both diseases. In this review, we summarize the current knowledge on NAFLD diagnosis, its systemic manifestations, and associations with CVD. More specifically, we review the pathophysiological mechanisms that govern the interplay between NAFLD and CVD and evaluate the relationship between different CVD treatments and NAFLD progression.