Non-alcoholic fatty liver disease and cardiovascular disease: assessing the evidence for causality

Metabolic dysfunction-associated fatty liver disease and heavy alcohol consumption increase mortality:A nationwide study

BACKGROUND

The effects of excessive alcohol consumption on the prognosis of metabolic dysfunction-associated fatty liver disease (MAFLD) remain unclear. We investigated all-cause and cause-specific mortality according to the amount of alcohol consumed by Asian individuals with MAFLD.

METHODS

This nationwide retrospective study included 996,508 adults aged 40-79 years who underwent health check-ups between 2009 and 2012. Participants were categorized by the alcohol consumption-non-alcohol, moderate alcohol, and heavy alcohol group (≥ 30 g/day for men, ≥ 20 g/day for women) and by the combination of the presence or absence of MAFLD. Hepatic steatosis was defined as the fatty liver index ≥ 30. Cox analyses were used to analyze the association between alcohol consumption and MAFLD and all-cause and cause-specific mortality.

RESULTS

MAFLD significantly increased all-cause, liver-, and cancer-related mortality. Individuals with both MAFLD and heavy alcohol consumption expressed the highest mortality risk in liver-related mortality compared to non-MAFLD and non-alcohol group (adjusted hazard ratio (HR), 9.8; 95% confidence interval (CI), 8.20-12.29). Regardless of MAFLD, heavy alcohol consumption increased the risk of liver- and cancer-related mortality.

CONCLUSIONS

MAFLD and heavy alcohol consumption increased all-cause, liver-, and cancer-related mortality. Heavy alcohol consumption and MAFLD synergistically increase liver-related mortality.

Type 1 diabetes mellitus and non-alcoholic fatty liver disease: a two-sample Mendelian randomization study

Background

NAFLD (Nonalcoholic fatty liver disease) is becoming an increasingly common cause of chronic liver disease. Metabolic dysfunction, overweight/obesity, and diabetes are thought to be closely associated with increased NAFLD risk. However, few studies have focused on the mechanisms of NAFLD occurrence in T1DM.

Methods

We conducted a two-sample Mendelian randomization (MR) analysis to assess the causal association between T1DM and NAFLD with/without complications, such as coma, renal complications, ketoacidosis, neurological complications, and ophthalmic complications. Multiple Mendelian randomization methods, such as the inverse variance weighted (IVW) method, weighted median method, and MR-Egger test were performed to evaluate the causal association of T1DM and NAFLD using genome-wide association study summary data from different consortia, such as Finngen and UK biobank.

Results

We selected 37 SNPs strongly associated with NAFLD/LFC (at a significance level of p < 5 × 10-8) as instrumental variables from the Finnish database based on the T1DM phenotype (8,967 cases and 308,373 controls). We also selected 14/16 SNPs based on with or without complications. The results suggest that the genetic susceptibility of T1DM does not increase the risk of NAFLD (OR=1.005 [0.99, 1.02], IVW p=0.516, MR Egger p=0.344, Weighted median p=0.959, Weighted mode p=0.791), regardless of whether complications are present. A slight causal effect of T1DM without complications on LFC was observed (OR=1.025 [1.00, 1.03], MR Egger p=0.045). However, none of the causal relationships were significant in the IVW (p=0.317), Weighted median (p=0.076), and Weighted mode (p=0.163) methods.

Conclusion

Our study did not find conclusive evidence for a causal association between T1DM and NAFLD, although clinical observations indicate increasing abnormal transaminase prevalence and NAFLD progression in T1DM patients.

Association of non-alcoholic fatty liver disease with cardiovascular disease and all cause death in patients with type 2 diabetes mellitus: nationwide population based study

OBJECTIVE

To investigate the risk of non-alcoholic fatty liver disease (NAFLD) for cardiovascular disease and all cause death in patients with type 2 diabetes mellitus (T2DM).

DESIGN

Nationwide population based study.

SETTING

Longitudinal cohort study in Korea.

PARTICIPANTS

7 796 763 participants in the National Health Screening Programme in 2009 were divided into three groups based on NAFLD status: no NAFLD (fatty liver index<30); grade 1 NAFLD (30≤fatty liver index<60); and grade 2 NAFLD (fatty liver index≥60). Median follow-up was 8.13 years.

MAIN OUTCOME MEASURES

The primary outcome was incident cardiovascular disease (myocardial infarction, ischaemic stroke) or all cause death.

RESULTS

Of 7 796 763 participants, 6.49% (n=505 763) had T2DM. More patients with T2DM had grade 1 NAFLD (34.06%) and grade 2 NAFLD (26.73%) than those without T2DM (grade 1 NAFLD: 21.20%; grade 2 NAFLD: 10.02%). The incidence rate (per 1000 person years) of cardiovascular disease and all cause death increased in the order of no NAFLD, grade 1 NAFLD, and grade 2 NAFLD, and the incidence rates in patients with T2DM were higher than those in patients without T2DM. The five year absolute risk for cardiovascular disease and all cause death increased in the order of no NAFLD, grade 1 NAFLD, and grade 2 NAFLD in patients without and with T2DM (no NAFLD, without T2DM: 1.03, 95% confidence interval 1.02 to 1.04, and 1.25, 1.24 to 1.26, respectively; grade 1 NAFLD, without T2DM: 1.23, 1.22 to 1.25, and 1.50, 1.48 to 1.51, respectively; grade 2 NAFLD, without T2DM: 1.42, 1.40 to 1.45, and 2.09, 2.06 to 2.12, respectively; no NAFLD, with T2DM: 3.34, 3.27 to 3.41, and 3.68, 3.61 to 3.74, respectively; grade 1 NAFLD, with T2DM: 3.94, 3.87 to 4.02, and 4.25, 4.18 to 4.33, respectively; grade 2 NAFLD, with T2DM: 4.66, 4.54 to 4.78, and 5.91, 5.78 to 6.05, respectively). Patients with T2DM and without NAFLD had a higher five year absolute risk for cardiovascular disease and all cause death than those without T2DM and with grade 2 NAFLD. Risk differences for cardiovascular disease and all cause death between no NAFLD and grade 1 or grade 2 NAFLD were higher in patients with T2DM than in those without T2DM.

CONCLUSIONS

NAFLD in patients with T2DM seems to be associated with a higher risk of cardiovascular disease and all cause death, even in patients with mild NAFLD. Risk differences for cardiovascular disease and all cause death between the no NAFLD group and the grade 1 or grade 2 NAFLD groups were higher in patients with T2DM than in those without T2DM.

Associations of non-alcoholic fatty liver disease and cirrhosis with liver cancer in European and East Asian populations: A Mendelian randomization study

BACKGROUND

The positive relationships of non-alcoholic fatty liver disease (NAFLD) and cirrhosis with liver cancer were shown in previous observational studies, while further Mendelian randomization (MR) investigations are needed to confirm the possible causal associations.

AIMS

This study aimed to explore whether NAFLD and cirrhosis were causally related to liver cancer using MR in European and East Asian populations.

METHODS AND RESULTS

For European populations, NAFLD data were obtained from a genome-wide meta-analysis (8434 patients and 770 180 controls). The data on chronic elevation of alanine aminotransferase (cALT), a proxy of NAFLD, were derived from Million Veteran Program (68 725 patients and 95 472 controls). Cirrhosis data were collected from two sources: a genome-wide association study of five cohorts (4829 patients and 72 705 controls) and FinnGen (1931 patients and 216 861 controls). Liver cancer data were collected from FinnGen (304 patients and 174 006 controls). For East Asian populations, the data on cirrhosis (2184 patients and 210 269 controls) and hepatocellular carcinoma (1866 patients and 195 745 controls) were obtained from Biobank Japan. Three, 41, seven, six, and three single-nucleotide polymorphisms were used for NAFLD (European), cALT (European), cirrhosis (European-five cohorts), cirrhosis (European-FinnGen), and cirrhosis (East Asian), respectively. We used inverse-variance weighted as the primary method to calculate the odds ratio (OR) and 95% confidence interval (CI). Among European populations, genetically-predicted NAFLD, cALT, cirrhosis (five cohorts), and cirrhosis (FinnGen) were positively associated with liver cancer, with ORs (95% CIs) of 6.62 (3.81-11.50) (p < .001), 2.59 (1.70-3.94) (p < .001), 3.38 (2.41-4.75) (p < .001), and 2.62 (1.20-5.72) (p = .015). Among East Asian populations, there was also a positive association between genetically-predicted cirrhosis and hepatocellular carcinoma (OR = 2.12; 95% CI = 1.78-2.52; p < .001).

CONCLUSION

This study utilized MR to complementarily confirm the positive connections of NAFLD and cirrhosis with liver cancer, as identified in earlier observational research. Subsequent MR investigations involving more liver cancer cases are needed.

How non-alcoholic fatty liver disease and cirrhosis affect the heart

Liver diseases affect the heart and the vascular system. Cardiovascular complications appear to be a leading cause of death in patients with non-alcoholic fatty liver disease (NAFLD) and cirrhosis. The predominant histological changes in the liver range from steatosis to fibrosis to cirrhosis, which can each affect the cardiovascular system differently. Patients with cirrhotic cardiomyopathy (CCM) and NAFLD are at increased risk of impaired systolic and diastolic dysfunction and for suffering major cardiovascular events. However, the pathophysiological mechanisms behind these risks differ depending on the nature of the liver disease. Accurate assessment of symptoms by contemporary diagnostic modalities is essential for identifying patients at risk, for evaluating candidates for treatment, and prior to any invasive procedures. This review explores current perspectives within this field.

Biomarkers of Hepatic Dysfunction and Cardiovascular Risk

PURPOSE OF REVIEW

The objective of this manuscript is to examine the current literature on non-alcoholic fatty liver disease (NAFLD) biomarkers and their correlation with cardiovascular disease (CVD) outcomes and cardiovascular risk scores.

RECENT FINDINGS

There has been a growing appreciation for an independent link between NAFLD and CVD, culminating in a scientific statement by the American Heart Association in 2022. More recently, studies have begun to identify biomarkers of the three NAFLD phases as potent predictors of cardiovascular risk. Despite the body of evidence supporting a connection between hepatic biomarkers and CVD, more research is certainly needed, as some studies find no significant relationship. If this relationship continues to be robust and readily reproducible, NAFLD and its biomarkers may have an exciting role in the future of cardiovascular risk prediction, possibly as risk-enhancing factors or as components of novel cardiovascular risk prediction models.

Comparative effectiveness of multiple different treatment regimens for nonalcoholic fatty liver disease with type 2 diabetes mellitus: a systematic review and Bayesian network meta-analysis of randomised controlled trials

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) are closely related and mutually contribute to the disease's development. There are many treatment options available to patients. We provide a comprehensive overview of the evidence on the treatment effects of several potential interventions for NAFLD with T2DM.

METHODS

This systematic review and network meta-analysis included searches of PubMed, Embase, Cochrane Library, and Web of Science from inception to June 30, 2023, for randomised controlled trials of treatment of NAFLD with T2DM. We performed Bayesian network meta-analyses to summarise effect estimates of comparisons between interventions. We applied the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) frameworks to rate all comparative outcomes' certainty in effect estimates, categorise interventions, and present the findings. This study was registered with PROSPERO, CRD42022342373.

RESULTS

Four thousand three hundred and sixty-nine records were retrieved from the database and other methods, of which 24 records were eligible for studies enrolling 1589 participants. Eight clinical indicators and 14 interventions were finally in focus. Referring to the lower surface under the cumulative ranking curves (SUCRA) and the league matrix table, exenatide and liraglutide, which are also glucagon-like peptide-1 receptor agonists (GLP-1RAs), showed excellent potential to reduce liver fat content, control glycemia, reduce body weight, and improve liver function and insulin resistance. Exenatide was more effective in reducing glycated haemoglobin (HbA1c) (mean difference (MD) 0.32, 95%CI 0.12 to 0.52), lowering BMI (MD 0.81, 95%CI 0.18 to 1.45), and lowering alanine transaminase (ALT) (MD 10.96, 95%CI 5.27 to 16.66) compared to liraglutide. However, this evidence was assessed as low certainty. Omega-3 was the only intervention that did not have a tendency to lower HbA1c, with standard-treatment (STA-TRE) as reference (MD - 0.17, 95%CI - 0.42 to 0.07). Glimepiride is the only intervention that causes an increase in ALT levels, with standard-treatment (STA-TRE) as reference (MD - 11.72, 95%CI - 17.82 to - 5.57). Based on the available evidence, the treatment effects of pioglitazone, dapagliflozin, and liraglutide have a high degree of confidence.

CONCLUSIONS

The high confidence mandates the confident application of these findings as guides for clinical practice. Dapagliflozin and pioglitazone are used for glycaemic control in patients with NAFLD combined with T2DM, and liraglutide is used for weight loss therapy in patients with abdominal obesity. The available evidence does not demonstrate the credibility of the effectiveness of other interventions in reducing liver fat content, visceral fat area, ALT, and insulin resistance. Future studies should focus on the clinical application of GLP-1Ras and the long-term prognosis of patients.

Biomarkers for Assessing Non-Alcoholic Fatty Liver Disease in Patients with Type 2 Diabetes Mellitus on Sodium-Glucose Cotransporter 2 Inhibitor Therapy

In the current modern era of unhealthy lifestyles, non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disease and has become a serious global health problem. To date, there is no approved pharmacotherapy for the treatment of NAFLD, and necessary lifestyle changes such as weight loss, diet, and exercise are usually not sufficient to manage this disease. Patients with type 2 diabetes mellitus (T2DM) have a significantly higher risk of developing NAFLD and vice versa. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are antidiabetic agents that have recently been approved for two other indications: chronic kidney disease and heart failure in diabetics and non-diabetics. They are also emerging as promising new agents for NAFLD treatment, as they have shown beneficial effects on hepatic inflammation, steatosis, and fibrosis. Studies in animals have reported favorable effects of SGLT2 inhibitors, and studies in patients also found positive effects on body mass index (BMI), insulin resistance, glucose levels, liver enzymes, apoptosis, and transcription factors. There are some theories regarding how SGLT2 inhibitors affect the liver, but the exact mechanism is not yet fully understood. Therefore, biomarkers to evaluate underlying mechanisms of action of SGLT2 inhibitors on the liver have now been scrutinized to assess their potential as a future in-label therapy for NAFLD. In addition, finding suitable non-invasive biomarkers could be helpful in clinical practice for the early detection of NAFLD in patients. This is crucial for a positive disease outcome. The aim of this review is to provide an overview of the most recent findings on the effects of SGLT2 inhibitors on NAFLD biomarkers and the potential of SGLT2 inhibitors to successfully treat NAFLD.

NAFLD, MAFLD, and beyond: one or several acronyms for better comprehension and patient care

The term non-alcoholic fatty liver disease (NAFLD) has rapidly become the most common type of chronic liver disease. NAFLD points to excessive hepatic fat storage and no evidence of secondary hepatic fat accumulation in patients with "no or little alcohol consumption". Both the etiology and pathogenesis of NAFLD are largely unknown, and a definitive therapy is lacking. Since NAFLD is very often and closely associated with metabolic dysfunctions, a consensus process is ongoing to shift the acronym NAFLD to MAFLD, i.e., metabolic-associated fatty liver disease. The change in terminology is likely to improve the classification of affected individuals, the disease awareness, the comprehension of the terminology and pathophysiological aspects involved, and the choice of more personalized therapeutic approaches while avoiding the intrinsic stigmatization due to the term "non-alcoholic". Even more recently, other sub-classifications have been proposed to concentrate the heterogeneous causes of fatty liver disease under one umbrella. While awaiting additional validation studies in this field, we discuss the main reasons underlying this important shift of paradigm.

Precision Medicine in Fatty Liver Disease/Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease, and is related to fatal and non-fatal liver, metabolic, and cardiovascular complications. Its non-invasive diagnosis and effective treatment remain an unmet clinical need. NAFLD is a heterogeneous disease that is most commonly present in the context of metabolic syndrome and obesity, but not uncommonly, may also be present without metabolic abnormalities and in subjects with normal body mass index. Therefore, a more specific pathophysiology-based subcategorization of fatty liver disease (FLD) is needed to better understand, diagnose, and treat patients with FLD. A precision medicine approach for FLD is expected to improve patient care, decrease long-term disease outcomes, and develop better-targeted, more effective treatments. We present herein a precision medicine approach for FLD based on our recently proposed subcategorization, which includes the metabolic-associated FLD (MAFLD) (i.e., obesity-associated FLD (OAFLD), sarcopenia-associated FLD (SAFLD, and lipodystrophy-associated FLD (LAFLD)), genetics-associated FLD (GAFLD), FLD of multiple/unknown causes (XAFLD), and combined causes of FLD (CAFLD) as well as advanced stage fibrotic FLD (FAFLD) and end-stage FLD (ESFLD) subcategories. These and other related advances, as a whole, are expected to enable not only improved patient care, quality of life, and long-term disease outcomes, but also a considerable reduction in healthcare system costs associated with FLD, along with more options for better-targeted, more effective treatments in the near future.

Diet and Exercise Exert a Differential Effect on Glucose Metabolism Markers According to the Degree of NAFLD Severity

BACKGROUND

Non-Alcoholic Fatty Liver Disease (NAFLD) and Type 2 Diabetes (T2D) are highly prevalent diseases worldwide. Insulin Resistance (IR) is the common denominator of the two conditions even if the precise timing of onset is unknown. Lifestyle change remains the most effective treatment to manage NAFLD. This study aimed to estimate the effect of the Low Glycemic Index Mediterranean Diet (LGIMD) and exercise (aerobic and resistance) over a one-year period on the longitudinal trajectories of glucose metabolism regulatory pathways.

MATERIALS AND METHODS

In this observational study, 58 subjects (aged 18-65) with different degrees of NAFLD severity were enrolled by the National Institute of Gastroenterology-IRCCS "S. de Bellis", to follow a 12-month program of combined exercise and diet.

RESULTS

The mean age was 55 ± 7 years old. Gender was equally distributed among NAFLD categories. There was a statistically significant main effect of time for glycosylated hemoglobin (Hb1Ac) over the whole period (-5.41, 95% CI: -7.51; -3.32). There was a steady, statistically significant decrease of HbA1c in participants with moderate and severe NAFLD whereas this effect was observed after the 9th month in those with mild NAFLD.

CONCLUSIONS

The proposed program significantly improves glucose metabolism parameters, especially HbA1c.

Extrahepatic Outcomes of Nonalcoholic Fatty Liver Disease: Cardiovascular Diseases

Patients with nonalcoholic fatty liver disease (NAFLD) are at high risk of cardiovascular disease, including carotid atherosclerosis, coronary artery disease, heart failure, and arrhythmias. The risk is partially due to shared risk factors, but it may vary according to liver injury. A fatty liver may induce an atherogenic profile, the local necro-inflammatory changes of nonalcoholic steatohepatitis may enhance systemic metabolic inflammation, and fibrogenesis can run parallel in the liver and in the myocardium and precedes heart failure. The detrimental impact of a Western diet combines with polymorphisms in genes associated with atherogenic dyslipidemia. Shared clinical/diagnostic algorithms are needed to manage the cardiovascular risk in NAFLD.

Fibrosis score 4 index has an independent relationship with coronary artery diseases in patients with metabolic-associated fatty liver disease

BACKGROUND

Metabolic-associated fatty liver disease (MAFLD), one of the most common liver diseases, is detected in patients with concomitant hepatic steatosis and Type 2 Diabetes (T2D). We looked into the relationship between Fibrosis-4 (FIB-4) index and coronary artery diseases (CAD) in patients with MAFLD, to further look into the efficiency of FIB-4 in screening for CAD among patients with MAFLD.

METHOD

In this study, we included 1664 patients with MAFLD (T2D, who also had hepatic steatosis) during 2012-2022 and divided them into 2 groups; CAD and non-CAD. Demographic, Anthropometric indices, liver function tests, lipid profile and FIB-4 index of all patients were evaluated and compared.

RESULT

Among the 1644 patients (all have MAFLD), 364(21.4%) had CAD. Patients with MAFLD and CAD were more probable to be hypertensive, have longer duration of diabetes and be older (with p-values < 0.001). After adjustment for confounding factors, in a multivariable logistic regression model, FIB4 showed a significant independent relationship with concomitant MAFLD and CAD. Upper Tertile FIB-4 had an odds ratio of 3.28 (P-value = 0.002) to predict CAD. Furthermore, in Receiver Operating Characteristic (ROC) Curve analysis with the maximum Youden Index, a FIB-4 cut-off of 0.85 (AUC = 0.656, 95% CI 0.618-0.693, P < 0.001) noted to predict CAD in patients with MAFLD.

CONCLUSION

This study showed that the FIB-4 score independently correlates with CAD in patients with MAFLD.

The Association between Advanced Liver Fibrosis and Mortality Is Modified by Dietary Quality among Korean Adults: Results from the Korea National Health and Nutrition Examination Survey with Mortality Data

Advanced fibrosis in nonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of mortality; however, an independent association of liver fibrosis with mortality is not well defined. We aimed to investigate the association between advanced liver fibrosis and all-cause and cardiovascular mortality and the mediation effect of diet quality. We analyzed 35,531 participants with suspected NAFLD, excluding competing etiologies of chronic liver disease, from the Korea National Health and Nutrition Examination Survey 2007-2015, and followed up until 31 December 2019. The severity of liver fibrosis was assessed using the NAFLD fibrosis score (NFS) and the fibrosis-4 index (FIB-4). The Cox proportional hazards model was used to examine the association of advanced liver fibrosis with mortality. During a mean 8.1 years of follow-up, 3426 deaths occurred. Advanced liver fibrosis determined by NFS and FIB-4 was associated with increased risks of all-cause and cardiovascular mortality after adjusting for confounders. When NFS and FIB-4 were combined, the high NFS + high FIB-4 group was significantly associated with higher risks of all-cause mortality (hazard ratio [HR] 1.85, 95% CI 1.42-2.43) and cardiovascular mortality (HR 2.04, 95% CI 1.23-3.39), respectively, compared with the low NFS + low FIB-4 group. However, these associations were attenuated in people with high diet quality. Advanced liver fibrosis is an independent risk factor for all-cause and cardiovascular mortality in people with NAFLD, and the association between advanced liver fibrosis and mortality is modified by a high-quality diet.

From NAFLD to MAFLD: Definition, Pathophysiological Basis and Cardiovascular Implications

Non-alcoholic fatty liver disease (NAFLD) is defined as a chronic liver disease characterized by excessive fat accumulation in the liver without another obvious cause (no excessive alcohol consumption, hepatotoxic medications, toxins, viral infections, genetic hepatic diseases), therefore it is an exclusion diagnosis. The term NAFLD literally refers to non-alcohol related hepatopathy and does not adequately correlate with metabolic dysfunction and related cardiovascular risks. Therefore, researchers and scientific societies have moved towards changing the terminology. The novel nomenclature for a metabolic-associated fatty liver disease (MAFLD) has been proposed in 2020 by a group of experts to overcome the issues related to the old terminology. The diagnosis of MAFLD is based on the presence of hepatic steatosis and at least one between these three conditions: type 2 diabetes mellitus (T2DM), obesity or metabolic dysregulation. MAFLD has been shown to be an independent risk factor for cardiovascular diseases and atherosclerosis. It is better related to the main risk factors for atherosclerosis and cardiovascular diseases than NAFLD, such as dyslipidemia, T2DM and hypertension. The aim of this review is to highlight the reasons why the term NAFLD is moving to the term MAFLD, what are the conceptual basis of this choice and its clinical implications, particularly in the cardiovascular field.

Nonalcoholic Fatty Liver Disease and Cardiovascular Disease: Causation or Association

Nonalcoholic fatty liver disease (NAFLD) is a disease process that is gaining increasing recognition. The global prevalence of NAFLD is increasing in parallel with growing rates of risk factors for NAFLD such as hypertension, obesity, diabetes, and metabolic syndrome. NAFLD has been referred to as a risk factor for cardiovascular disease (CVD). As CVD is the leading cause of morbidity and mortality worldwide, there are constant efforts to describe and alleviate its risk factors. Although there is conflicting data supporting NAFLD as a causative or associative factor for CVD, NAFLD has been shown to be associated with structural, electrical, and atherosclerotic disease processes of the heart. Shared risk factors and pathophysiologic mechanisms between NAFLD and CVD warrant further explication. Pathologic mechanisms such as endothelial dysfunction, oxidative stress, insulin resistance, genetic underpinnings, and gut microbiota dysregulation have been described in both CVD and NAFLD. The mainstay of treatment for NAFLD is lifestyle intervention including physical exercise and hypocaloric intake in addition to bariatric surgery. Investigations into various therapeutic targets to alleviate hepatic steatosis and fibrosis by way of maintaining the balance between lipid synthesis and breakdown. A major obstacle preventing the success of many pharmacologic approaches has been the effects of these medications on CVD risk. The future of pharmacologic treatment of NAFLD is promising as effective medications with limited CVD harm are being investigated.

The role of hepatokines in NAFLD

Non-alcoholic fatty liver disease (NAFLD) is not only a consequence of insulin resistance, but it is also an important cause of insulin resistance and major non-communicable diseases (NCDs). The close relationship of NAFLD with visceral obesity obscures the role of fatty liver from visceral adiposity as the main pathomechanism of insulin resistance and NCDs. To overcome this limitation, in analogy to the concept of adipokines, in 2008 we introduced the term hepatokines to describe the role of fetuin-A in metabolism. Since then, several other hepatokines were tested for their effects on metabolism. Here we address the dysregulation of hepatokines in people with NAFLD. Then, we discuss pathophysiological mechanisms of cardiometabolic diseases specifically related to NAFLD by focusing on hepatokine-related organ crosstalk. Finally, we propose how the determination of major hepatokines and adipokines can be used for pathomechanism-based clustering of insulin resistance in NAFLD and visceral obesity to better implement precision medicine in clinical practice.

Influence of non-alcoholic fatty liver disease on non-variceal upper gastrointestinal bleeding: A nationwide analysis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is the leading cause of liver disease globally with an estimated prevalence of 25%, with the clinical and economic burden expected to continue to increase. In the United States, non-variceal upper gastrointestinal bleeding (NVUGIB) has an estimated incidence of 61-78 cases per 100000 people with a mortality rate of 2%-15% based on co-morbidity burden.

AIM

To identify the outcomes of NVUGIB in NAFLD hospitalizations in the United States.

METHODS

We utilized the National Inpatient Sample from 2016-2019 to identify all NVUGIB hospitalizations in the United States. This population was divided based on the presence and absence of NAFLD. Hospitalization characteristics, outcomes and complications were compared.

RESULTS

The total number of hospitalizations for NVUGIB was 799785, of which 6% were found to have NAFLD. NAFLD and GIB was, on average, more common in younger patients, females, and Hispanics than GIB without NAFLD. Interestingly, GIB was less common amongst blacks with NAFLD. Multivariate logistic regression analysis was conducted, controlling for the multiple covariates. The primary outcome of interest, mortality, was found to be significantly higher in patients with NAFLD and GIB [adjusted odds ratio (aOR) = 1.018 (1.013-1.022)]. Secondary outcomes of interest, shock [aOR = 1.015 (1.008-1.022)], acute respiratory failure [aOR = 1.01 (1.005-1.015)] and acute liver failure [aOR = 1.016 (1.013-1.019)] were all more likely to occur in this cohort. Patients with NAFLD were also more likely to incur higher total hospital charges (THC) [$2148 ($1677-$2618)]; however, were less likely to have a longer length of stay [0.27 d (0.17-0.38)]. Interestingly, in our study, the patients with NAFLD were less likely to suffer from acute myocardial infarction [aOR = 0.992 (0.989-0.995)]. Patients with NAFLD were not more likely to suffer acute kidney injury, sepsis, blood transfusion, intubation, or dialysis.

CONCLUSION

NVUGIB in NAFLD hospitalizations had higher inpatient mortality, THC, and complications such as shock, acute respiratory failure, and acute liver failure compared to those without NAFLD.

Relationship between NAFLD and coronary artery disease: A Mendelian randomization study

BACKGROUND AND AIMS

There is an ongoing debate on whether NAFLD is an active contributor or an innocent bystander in the pathogenesis of coronary artery disease (CAD). The aim of the present study was to assess the causal relationship between NAFLD and CAD.

APPROACH AND RESULTS

We performed two-sample Mendelian randomization (MR) analyses using summary-level data to assess the association between genetically predicted NAFLD (i.e., chronically elevated serum alanine aminotransferase levels [cALT], imaging-based and biopsy-confirmed NAFLD) and risk of CAD. Analyses were repeated after exclusion of NAFLD susceptibility genes that are associated with impaired VLDL secretion.Inverse-variance weighted MR analyses showed a statistically significant association between genetically predicted cALT and risk of CAD (OR: 1.116, 95% CI: 1.039, 1.199), but not for the other NAFLD-related traits (OR: 1.046, 95% CI: 0.764, 1.433 and OR: 1.014, 95% CI: 0.968, 1.062 for imaging-based and biopsy-confirmed NAFLD, respectively). MR-Egger regression revealed a statistically significant intercept, indicative of directional pleiotropy, for all traits. Repeat analyses after exclusion of genes associated with impaired VLDL secretion showed consistent associations between genetically predicted NAFLD and CAD for all traits (i.e., cALT [OR: 1.203, 95% CI: 1.113, 1.300]), imaging-based (OR: 2.149, 95% CI: 1.276, 3.620) and biopsy-confirmed NAFLD (OR: 1.113, 95% CI: 1.041, 1.189), which persisted when more stringent biopsy-confirmed NAFLD criteria were used (OR: 1.154, 95% CI: 1.043, 1.278) or when more stringent MR methods were applied. MR-Egger regression did not show a statistically significant intercept.

CONCLUSION

The two-sample MR analyses showed a robust association between genetically predicted NAFLD and CAD after exclusion of genetic variants that are implicated in impaired VLDL secretion.

MBOAT7 rs641738 variant in metabolic-dysfunction-associated fatty liver disease and cardiovascular risk

Introduction

Although metabolic-dysfunction-associated fatty liver disease (MAFLD) is associated with an increased cardiovascular risk, MAFLD predisposing genetic variants were not steadily related to cardiovascular events. Therefore, we aimed to assess whether membrane-bound O-acyltransferase domain-containing 7 (MBOAT7) rs641738 variant is associated with an increased cardiovascular risk in in MAFLD patients.

Methods

We conducted an observational cross-sectional study including 77 subjects (38 MAFLD patients, 39 controls), between January-September 2020 using hepatic ultrasonography and SteatoTest^TM to assess hepatic steatosis. Echocardiographic and Doppler ultrasound parameters were evaluated. Genomic DNA was extracted and rs641738 SNP was genotyped using TaqMan assays.

Results

The rs641738 variant was not significantly associated with MAFLD, with a p-value of 0.803, 0.5265, 0.9535, and 0.5751 for codominant, dominant, recessive, and overdominant genotypes, respectively. The rs641738 variant overdominant genotype significantly predicted atherosclerotic cardiovascular disease (ASCVD) risk algorithm in univariate analysis (-4.3 [95% CI -8.55 - -0.55, p-value= 0.048]), but lost significance after multivariate analysis (-3.98 [95% CI -7.9 - -0.05, p-value= 0.053]). The rs641738 variant recessive genotype significantly predicted ActiTest in univariate analysis (0.0963 [95% CI 0.0244 - 0.1681, p-value= 0.009]), but lost significance after multivariate analysis (0.0828 [95% CI -0.016 - 0.1816, p-value= 0.105]).

Conclusion

No significant association was observed between rs641738 variant and MAFLD in the studied population. The rs641738 variant was found to predict ASCVD risk score and ActiTest in univariate linear regression analysis. However, the significance of both associations was lost after performing multivariate analysis.

Nonlinear correlation between fatty liver index and carotid intima media thickness among individuals undergoing health examination

BACKGROUND

Fatty liver index (FLI) is a predictor of non-alcohol fatty liver disease (NAFLD). This study aimed to assess the association between FLI and carotid intima media thickness (CIMT).

METHODS

In this cross-sectional study, we enrolled 277 individuals for health examination from the China-Japan Friendship Hospital. Blood sampling and ultrasound examinations were conducted. Multivariate logistic regression and restricted cubic spline analyses were performed to evaluate the association between FLI and CIMT.

RESULTS

Overall, 175 (63.2%) and 105 (37.9%) individuals had NAFLD and CIMT, respectively. The multivariate logistic regression analyses results showed that high FLI was independently associated with a high risk of increased CIMT, T2 vs. T1 (odds ratio [OR], 95% confidence interval [CI]): 2.41, 1.10-5.25, p = 0.027; T3 vs. T1 (OR, 95% CI): 1.58, 0.68-3.64, p = 0.285. The association between FLI and increased CIMT exhibited a J-shaped curve (nonlinear, p = 0.019). In the threshold analysis, the OR for developing increased CIMT was 1.031 (95% CI: 1.011-1.051, p = 0.0023) in participants with FLI < 64.247.

CONCLUSION

The relationship between FLI and increased CIMT in the health examination population is J-shaped, with an inflection point of 64.247.

Serum sex hormone-binding globulin is a mediator of the association between intrahepatic lipid content and type 2 diabetes: the Maastricht Study

AIMS/HYPOTHESIS

Serum sex hormone-binding globulin (SHBG) has been proposed to act as a hepatokine that contributes to the extrahepatic complications observed in non-alcoholic fatty liver disease (NAFLD). However, it remains uncertain whether serum SHBG mediates the association between intrahepatic lipids (IHL) and type 2 diabetes. Therefore, we studied whether, and to what extent, serum SHBG mediates the association between IHL content and type 2 diabetes.

METHODS

We used cross-sectional data from the Maastricht Study (n=1554), a population-based cohort study with oversampling of individuals with type 2 diabetes. Type 2 diabetes status was assessed by oral glucose tolerance test, and IHL content was measured using 3T Dixon MRI. Mediation analyses were performed to assess the role of serum SHBG in mediating the association between IHL content and type 2 diabetes.

RESULTS

IHL content was significantly associated with type 2 diabetes in women and men (OR 1.08 [95% CI 1.04, 1.14] and OR 1.12 [95% CI 1.08, 1.17], respectively). Serum SHBG significantly mediated the association between IHL content and type 2 diabetes. The contribution of serum SHBG was higher in women (OR 1.04 [95% CI 1.02, 1.07]; proportion mediated 50.9% [95% CI 26.7, 81.3]) than in men (OR 1.02 [95% CI 1.01, 1.03]; proportion mediated 17.2% [95% CI 9.6, 27.6]). Repeat analyses with proxies of type 2 diabetes and adjustment for covariates did not substantially affect the results.

CONCLUSIONS/INTERPRETATION

In this large-scale population-based cohort study, serum SHBG was found to be a mediator of the association between IHL content and type 2 diabetes. These findings extend our understanding of the potential mechanisms by which NAFLD is a risk factor for type 2 diabetes, and further elaborate on the role of SHBG as a hepatokine.

Lessons on Drug Development: A Literature Review of Challenges Faced in Nonalcoholic Fatty Liver Disease (NAFLD) Clinical Trials

NAFLD is the most common chronic liver disease worldwide, occurring in both obese and lean patients. It can lead to life-threatening liver diseases and nonhepatic complications, such as cirrhosis and cardiovascular diseases, that burden public health and the health care system. Current care is weight loss through diet and exercise, which is a challenging goal to achieve. However, there are no FDA-approved pharmacotherapies for NAFLD. This review thoroughly examines the clinical trial findings from 22 drugs (Phase 2 and above) and evaluates the future direction that trials should take for further drug development. These trialed drugs can broadly be categorized into five groups-hypoglycemic, lipid-lowering, bile-pathway, anti-inflammatory, and others, which include nutraceuticals. The multitude of challenges faced in these yet-to-be-approved NAFLD drug trials provided insight into a few areas of improvement worth considering. These include drug repurposing, combinations, noninvasive outcomes, standardization, adverse event alleviation, and the need for precision medicine with more extensive consideration of NAFLD heterogenicity in drug trials. Understandably, every evolution of the drug development landscape lies with its own set of challenges. However, this paper believes in the importance of always learning from lessons of the past, with each potential improvement pushing clinical trials an additional step forward toward discovering appropriate drugs for effective NAFLD management.

Antitumor Effects and Mechanisms of Metabolic Syndrome Medications on Hepatocellular Carcinoma

Liver cancer has a high incidence and mortality rate worldwide, with hepatocellular carcinoma (HCC) being the most common histological type. With the decrease in the number of newly infected patients and the spread of antiviral therapy, hepatitis virus-negative chronic liver diseases including steatohepatitis are increasingly accounting for a large proportion of HCC, and an important clinical characteristic is the high prevalence of metabolic syndrome including hypertension, type 2 diabetes (T2D), dyslipidemia, and obesity. Since patients with steatohepatitis are less likely to undergo surveillance for early detection of HCC, they may be diagnosed at an advanced stage and have worse prognosis. Therefore, treatment strategies for patients with HCC caused by steatohepatitis, especially in advanced stages, become increasingly important. Further, hypertension, T2D, and dyslipidemia may occur as side effects during systemic treatment, and there will be increasing opportunities to prescribe metabolic syndrome medications, not only for originally comorbid diseases, but also for adverse events during HCC treatment. Interestingly, epidemiological studies have shown that patients taking some metabolic syndrome medications are less likely to develop various types of cancers, including HCC. Basic studies have also shown that these drugs have direct antitumor effects on HCC. In particular, angiotensin II receptor blockers (a drug group for treating hypertension), biguanides (a drug group for treating T2D), and statins (a drug group for treating dyslipidemia) have shown to elucidate antitumor effects against HCC. In this review, we focus on the antitumor effects of metabolic syndrome medications on HCC and their mechanisms based on recent literature. New therapeutic agents are also increasingly being reported. Analysis of the antitumor effects of metabolic syndrome medications on HCC and their mechanisms will be doubly beneficial for HCC patients with metabolic syndrome, and the use of these medications may be a potential strategy against HCC.

Obesity and cardiovascular disease: mechanistic insights and management strategies. A joint position paper by the World Heart Federation and World Obesity Federation

The ongoing obesity epidemic represents a global public health crisis that contributes to poor health outcomes, reduced quality of life, and >2.8 million deaths each year. Obesity is relapsing, progressive, and heterogeneous. It is considered a chronic disease by the World Obesity Federation (WOF) and a chronic condition by the World Heart Federation (WHF). People living with overweight/obesity are at greater risk for cardiovascular (CV) morbidity and mortality. Increased adiposity (body fat), particularly visceral/abdominal fat, is linked to CV risk and CV disease (CVD) via multiple direct and indirect pathophysiological mechanisms. The development of CVD is driven, in part, by obesity-related metabolic, endocrinologic, immunologic, structural, humoral, haemodynamic, and functional alterations. The complex multifaceted nature of these mechanisms can be challenging to understand and address in clinical practice. People living with obesity and CVD often have concurrent chronic physical or psychological disorders (multimorbidity) requiring multidisciplinary care pathways and polypharmacy. Evidence indicates that intentional weight loss (particularly when substantial) lowers CVD risk among people with overweight/obesity. Long-term weight loss and maintenance require ongoing commitment from both the individual and those responsible for their care. This position paper, developed by the WOF and the WHF, aims to improve understanding of the direct and indirect links between overweight/obesity and CVD, the key controversies in this area and evidence relating to cardiometabolic outcomes with available weight management options. Finally, an action plan for clinicians provides recommendations to help in identifying and addressing the risks of obesity-related CVD (recognizing resource and support variances between countries).

Association between de novo lipogenesis susceptibility genes and coronary artery disease

BACKGROUND AND AIMS

Coronary artery disease (CAD) is the principal cause of death in individuals with non-alcoholic fatty liver disease (NAFLD). The aim of this study was to use genetic epidemiology to study the association between de novo lipogenesis (DNL), one of the major pathways leading to NAFLD, and CAD risk.

METHODS AND RESULTS

DNL susceptibility genes were used as instruments and selected using three approaches: 1) genes that are associated with both high serum triglycerides and low sex hormone-binding globulin, both downstream consequences of DNL (unbiased approach), 2) genes that have a known role in DNL (biased approach), and 3) genes that have been associated with serum fatty acids, used as a proxy of DNL. Gene-CAD effect estimates were retrieved from the meta-analysis of CARDIoGRAM and the UK Biobank (∼76014 cases and ∼264785 controls). Effect estimates were clustered using a fixed-effects meta-analysis. Twenty-two DNL susceptibility genes were identified by the unbiased approach, nine genes by the biased approach and seven genes were associated with plasma fatty acids. Clustering of genes selected in the unbiased and biased approach showed a statistically significant association with CAD (OR:1.016, 95%CI:1.012; 1.020 and OR:1.013, 95%CI:1.007; 1.020, respectively), while clustering of fatty acid genes did not (OR:1.004, 95%CI:0.996-1.011). Subsequent exclusion of potential influential outliers did reveal a statistically significant association (OR:1.009, 95%CI:1.000; 1.018).

CONCLUSIONS

DNL susceptibility genes are associated with an increased risk of CAD. These findings suggest that DNL may be involved in the pathogenesis of CAD and favor further development of strategies that target NAFLD through DNL.

Fructose 1-phosphate, an evolutionary signaling molecule of abundancy

Evidence is accumulating that specifically fructose exerts adverse cardiometabolic effects in humans. Recent experimental studies have shown that fructose not only serves as a substrate for, among others, intrahepatic lipid formation, but also has a signaling function. It is postulated that fructose 1-phosphate (F1-P) has evolved as a signaling molecule of abundancy that stimulates nutrient absorption, lipid storage, and reproduction. Such a role would provide an explanation for why fructose contributes to the pathogenesis of evolutionary mismatch diseases, including nonalcoholic fatty liver disease (NAFLD), cardiovascular disease, polycystic ovary syndrome (PCOS), and colorectal cancer, in the current era of nutritional abundance. It is anticipated that reducing F1-P, by either pharmacological inhibition of ketohexokinase (KHK) or societal measures, will mitigate the risk of these diseases.

Relationship between nonalcoholic fatty liver disease and coronary plaque stability and risk factors for composite cardiovascular adverse events

BACKGROUND

Cardiovascular disease is a major disease threatening human life and health. In recent years, the relationship between cardiovascular disease and non-alcoholic fatty liver disease has become a research hotspot. Non-alcoholic fatty liver disease is closely related to the severity of coronary heart disease, which can be used for preliminary assessment of the risk of cardiovascular events in coronary heart disease.

AIM

To explore the relationship between non-alcoholic fatty liver disease (NAFLD) and coronary plaque stability and the multivariate analysis of prognosis.

METHODS

A total of 320 patients who underwent coronary CT angiography at our hospital from January 2019 to January 2021 were selected and divided into an NAFLD group (n = 91) and a non-NAFLD group (n = 229) according to the presence or absence of NAFLD. The general data and coronary plaque presence (plaque presence rate and plaque number) were compared between the two groups, and coronary plaque stability (soft plaque, mixed plaque, and hard plaque) in NAFLD patients with different degrees of fatty liver degeneration were compared. Spearman correlation was used to analyze the correlation between the degree of fatty liver degeneration and coronary plaque stability and Gensini score. All patients were followed for 12 mo, and composite cardiovascular adverse events (coronary revascularization, myocardial infarction, all-cause death, and cardiac death) were counted. The clinical data of patients with different prognoses were compared, and the prognostic factors were analyzed by multivariate Logistic regression.

RESULTS

The proportion of patients with coronary plaques (76.92%) and the proportion of patients with ≥ 2 coronary plaques (12.09%) in the NAFLD group were significantly higher than those in the non-NAFLD group (58.08% and 4.37%, respectively, P < 0.05). Patients with severe fatty liver degeneration had the highest proportion of soft plaques and Gensini score followed by those with moderate and mild fatty liver degeneration (P < 0.05); the degree of fatty liver degeneration in the NAFLD group was positively correlated with coronary plaque stability and Gensini score (P < 0.05). Body mass index, proportion of patients with diabetes, TG level, proportion of patients with NAFLD, and proportion of soft plaques in patients with composite adverse cardiovascular events were higher than those in patients without (P < 0.05). BMI, diabetes, TG level, NAFLD, and soft plaque were independent risk factors for compound cardiovascular adverse events (P < 0.05).

CONCLUSION

NAFLD is closely related to the stability of coronary plaque and the degree of coronary stenosis in CVD patients, and both NAFLD and coronary plaque instability are prognostic risk factors for composite cardiovascular adverse events.

Novel insights in intestinal and hepatic fructose metabolism: from mice to men

PURPOSE OF REVIEW

The rise in fructose consumption in parallel with the current epidemic of obesity and related cardiometabolic disease requires a better understanding of the pathophysiological pathways that are involved.

RECENT FINDINGS

Animal studies have shown that fructose has various effects on the intestines that subsequently affect intrahepatic lipid accumulation and inflammation. Fructose adversely affects the gut microbiome - as a producer of endotoxins and intermediates of de novo lipogenesis - and intestinal barrier function. Furthermore, intestinal fructose metabolism shields fructose away from the liver. Finally, fructose 1-phosphate (F1-P) serves as a signal molecule that promotes intestinal cell survival and, consequently, intestinal absorption capacity. Intervention and epidemiological studies have convincingly shown that fructose, particularly derived from sugar-sweetened beverages, stimulates de novo lipogenesis and intrahepatic lipid accumulation in humans. Of interest, individuals with aldolase B deficiency, who accumulate F1-P, are characterized by a greater intrahepatic lipid content. First phase II clinical trials have recently shown that reduction of F1-P, by inhibition of ketohexokinase, reduces intrahepatic lipid content.

SUMMARY

Experimental evidence supports current measures to reduce fructose intake, for example by the implementation of a tax on sugar-sweetened beverages, and pharmacological inhibition of fructose metabolism to reduce the global burden of cardiometabolic disease.

Time to transition from a negative nomenclature describing what NAFLD is not, to a novel, pathophysiology-based, umbrella classification of fatty liver disease (FLD)

Non-alcoholic fatty liver disease (NAFLD) is a definition of a prevalent condition that has been given a name describing what the disease is not, mainly due to gaps in the physiopathological understanding of NAFLD when the name was given to it. NAFLD still remains an unmet clinical need to a large extent due to the heterogenicity of the disease and the lack of a more accurate physiology-based classification. In essence, fatty liver disease (FLD) has a multifactorial etiology, including metabolic abnormalities, environmental influences, genetic disorders, and/or their overlap which makes it difficult to diagnose, design appropriate trials for it and treat this disease. Therefore, we propose herein that as our knowledge about this disease continues to grow exponentially, it is time to consider ending this unspecific, negative and broad classification of NAFLD, and turn it into a positive and targeted one describing what the disease is and not what it is not. Thus, we propose the novel FLD "Mantzoros classification". This innovative classification proposes to classify the heterogeneous causes of FLD under one umbrella and eventually lead to a better nomenclature and classification system reflecting pathophysiology. This in turn could lead to both better clinical trials and more personalized care. An additional aim is to generate a dialogue among the experts in this field to eventually reach the right nomenclature for an appropriate disease classification that would facilitate our understanding, approach, diagnosis, and management of this epidemic of FLD. Overall, a novel classification, based on phenotypic manifestations, leading risk factors and probable causes of FLD, could help our understanding and clinically would be accurately defining and differentiating the disease, leading to a more accurate design and execution of clinical trials. This would in turn lead to tangible benefits for all patients suffering from FLD through targeted and more effective personalized treatments.

The genetic interactions between non-alcoholic fatty liver disease and cardiovascular diseases

The ongoing debate on whether non-alcoholic fatty liver disease (NAFLD) is an active contributor or an innocent bystander in the development of cardiovascular disease (CVD) has sparked interests in understanding the common mediators between the two biologically distinct entities. This comprehensive review identifies and curates genetic studies of NAFLD overlapping with CVD, and describes the colinear as well as opposing correlations between genetic associations for the two diseases. Here, CVD described in relation to NAFLD are coronary artery disease, cardiomyopathy and atrial fibrillation. Unique findings of this review included certain NAFLD susceptibility genes that possessed cardioprotective properties. Moreover, the complex interactions of genetic and environmental risk factors shed light on the disparity in genetic influence on NAFLD and its incident CVD. This serves to unravel NAFLD-mediated pathways in order to reduce CVD events, and helps identify targeted treatment strategies, develop polygenic risk scores to improve risk prediction and personalise disease prevention.

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.

Nonalcoholic fatty liver disease and cardiovascular diseases: A Mendelian randomization study

BACKGROUND

Evidence suggests that nonalcoholic fatty liver disease (NAFLD) is associated with cardiovascular diseases (CVDs). However, the results are inconsistent, and the causality remains to be established.

OBJECTIVE

We aimed to investigate the potential causal relationship between NAFLD and CVDs, including arterial stiffness, coronary artery disease, heart failure, stroke, ischemic stroke and its subtypes using two-sample Mendelian randomization (MR).

METHODS

Genetic instruments were used as proxies for NAFLD. Publicly available summary-level data were obtained from the UK Biobank, the CARDIoGRAMplusC4D Consortium, the MEGASTROKE Consortium, and other consortia. Six complementary MR methods were performed, including inverse variance weighted method (IVW), MR-Egger, weighted median, weighted mode, MR-PRESSO, and MR-RAPS.

RESULTS

NAFLD was significantly associated with arterial stiffness (β = 0.04 [95%CI, 0.02-0.06], P = 5.53E-04). Moreover, the results remained consistent and robust in the sensitivity analysis. As for heart failure, the IVW method suggested that NAFLD was significantly associated with heart failure (OR = 1.08, 95%CI: 1.02-1.14, P = 0.005) in the absence of pleiotropy. However, there were no significant associations of NAFLD with coronary artery disease, stroke, ischemic stroke, or any ischemic stroke subtype.

CONCLUSION

The MR study supported the causal effect of NAFLD on arterial stiffness. However, the study did not provide enough evidence suggesting the causal associations of NAFLD with heart failure, coronary artery disease, and any stroke subtypes.

Risk for hepatic and extra-hepatic outcomes in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is defined by presence of steatosis in more than 5% of liver cells. The gold standard for diagnosis is liver biopsy, but this is seldom achieved due to costs and risk for side effects, and that is why the diagnosis is mostly made based on a combination of radiology and exclusion of other liver diseases. Disease severity staging can be noninvasively achieved with radiological exams such as elastography or blood-based markers that usually have lower sensitivity and specificity. NAFLD is today the most common chronic liver disease globally with a prevalence estimated to be 25%. Fortunately, for many persons NAFLD is an incidental finding with a good prognosis. Whilst a major focus has been on liver-related outcomes in NAFLD, there has recently been an increased interest in extrahepatic consequences of NAFLD. The most commonly studied outcomes include cardiovascular disease and cancer. The risk of adverse outcomes generally differs according to the baseline fibrosis stage. There is a five-time higher risk of liver-related events in NAFLD patients with fibrosis stage 3 as compared to those with no or little fibrosis. Meanwhile, the presence of nonalcoholic steatohepatitis (NASH) does not seem to influence prognosis in addition to fibrosis stage. Patients with NAFLD clearly have a higher risk for cardiovascular outcomes compared to the general population, with a recent meta-analysis indicating a 37% increased hazard for cardiovascular events as opposed to individuals without NAFLD. The risk of liver cancer is increased, which is mostly driven by presence of cirrhosis, but the increased risk is present also in patients without cirrhosis, and to a greater extent than for other chronic liver disease. Around one-third of patients with NAFLD and liver cancer do not have cirrhosis. Additionally, the risk of extrahepatic malignancies is thought to be moderately increased, with most evidence for a link between NAFLD and colorectal cancer where the risk is approximately 50% higher compared to patients without NAFLD. A particularly salient point is if NAFLD can be considered an independent risk factor for outcomes. Many studies have not been able to adjust for key confounders, or suffer from different forms of bias. The clinical problem is nevertheless to identify persons with an increased risk for adverse hepatic and extrahepatic outcomes. We here discuss the evidence linking NAFLD to severe hepatic and extrahepatic outcomes.

Genetic variants associated with metabolic dysfunction-associated fatty liver disease in western China

INTRODUCTION

We aimed to confirm the association between some single nucleotide polymorphisms (SNPs) and metabolic dysfunction-associated fatty liver disease (MAFLD) in western China.

METHODS

A total of 286 cases and 250 healthy controls were enrolled in our study. All samples were genotyped for patatin-like phospholipase domain containing 3 (PNPLA3) rs738409, transmembrane 6 superfamily member 2 (TM6SF2) rs58542926, membrane-bound O-acyltransferase domain containing 7 (MBOAT7) rs641738, glucokinase regulator (GCKR) rs1260326 and rs780094, and GATA zinc finger domain containing 2A (GATAD2A) rs4808199. Using logistic regression analysis, we evaluated the association between MAFLD and each SNP under different models. Multiple linear regression was used to find the association between SNPs and laboratory characteristics. Multifactor dimensionality reduction was applied to test SNP-SNP interactions.

RESULTS

The recessive model and additive model of PNPLA3 rs738409 variant were related to MAFLD (odds ratio [OR] = 1.791 and 1.377, respectively, p = 0.038 and 0.027, respectively). However, after Benjamini-Hochberg adjustment for multiple tests, all associations were no longer statistically significant. PNPLA3 rs738409 correlated with AST levels. GCKR rs780094 and rs1260326 negatively correlated with serum glucose but positively correlated with triglycerides in MAFLD. Based on MDR analysis, the best single-locus and multilocus models for MAFLD risk were rs738409 and six-locus models, respectively.

CONCLUSIONS

In the Han population in western China, no association was found between these SNPs and the risk of MAFLD. PNPLA3 rs738409 was associated with aspartate aminotransferase levels in MAFLD patients. GCKR variants were associated with increased triglyceride levels and reduced serum fasting glucose in patients with MAFLD.

Carotid intima media as predictor of liver fibrosis in type 2 diabetes mellitus with NAFLD

BACKGROUND AND AIMS

Non Alcoholic Fatty Liver Disease (NAFLD) is common in type 2 Diabetes Mellitus (DM) that might progress to advance liver fibrosis. Early recognition of liver fibrosis may have clinical implication. Non invasive assessment tool for severity of liver fibrosis in NAFLD is expensive fibroscan. An alternate method of diagnosis will be very useful innovation. We aimed to evaluate Carotid Intima Media Thickness (CIMT) and its association with severity of liver fibrosis in patients with type 2 DM and NAFLD.

METHODS

Treatment naïve patients with type 2 DM were enrolled. Measurement of CIMT, hepatic ultrasound and fibroscan were done. Liver function tests included hepatic transaminases. The data obtained was subjected to statistical analysis using IBM SPSS version 20.0 software.

RESULT

Prevalence of NAFLD was 76% including 12% with moderate to advance liver fibrosis in patients with type 2 DM. CIMT was significantly higher in patients with NAFLD than with normal liver. CIMT positively correlated with severity of liver fibrosis measured by fibroscan. ROC curve analysis showed right CIMT value of 0.575 mm predicting liver fibrosis with sensitivity of 91.7% and specificity of 78.9%.

CONCLUSION

Three fourth of patients with type 2 DM had NAFLD but small proportion had moderate to advance liver fibrosis. CIMT increased more in patients with NAFLD than with normal liver in T2DM. CIMT value of 0.575 mm has a good sensitivity to predict liver fibrosis and therefore, it can be a reliable marker of severity of Non Alcoholic Steato Hepatitis (NASH) in diabetes with NAFLD.

NEAT1: A novel long non-coding RNA involved in mediating type 2 diabetes and its various complications

Background:

Nuclear‐enriched abundant transcript 1 (abbreviated as NEAT1) refers to a long-chain non-coding RNA involved within various physiological and pathological processes. This study aimed at clarifying the effect and molecule system of neat1 within nonalcoholic fatty liver disease (NAFLD) as well as type 2 diabetes (T2DM).

Method:

In this review, we summarize and analyze current studies concerning mechanisms of NEAT1 in the development of type 2 diabetes and its complications. Also, we search the papers of NEAT1 in applying to NAFLD. The related studies were obtained through a systematic search of Pubmed.

Results:

Neat1 displays a close correlation with how T2DM occurs and develops, and it was confirmed to be significantly up-regulated in T2DM and its various complications (e.g., diabetics nephropathy, diabetics cardiomyopathy, diabetics retinopathy as well as diabetic neuropathy). Besides, neat1 is capable of impacting the occurrence, development and prognosis of NAFLD and T2DM.

Conclusion:

LncRNA neat1 is likely to act as a novel therapeutic target for and T2DM and its complications. Moreover, nonalcoholic fatty liver disease is also correlated with NEAT1.

Causal relationship between polycystic ovary syndrome and coronary artery disease: A Mendelian randomisation study

OBJECTIVE

Polycystic ovary syndrome (PCOS) has been associated with an increased risk of coronary artery disease (CAD). However, it remains uncertain whether this increased risk is the result of PCOS per se or, alternatively, is explained by obesity, a common feature of PCOS. The aim of this study was to assess the causal association between PCOS and CAD and the role of obesity herein.

DESIGN AND METHODS

We conducted two-sample Mendelian randomisation analyses in large-scale, female-specific datasets to study the association between genetically predicted (1) risk of PCOS and risk of CAD, (2) body mass index (BMI) and risk of PCOS and (3) BMI and risk of CAD. Primary analyses were conducted with the inverse-variance weighted (IVW) method. Simple median, penalized weighted median and contamination mixture analyses were performed to assess the robustness of the outcomes.

RESULTS

IVW analyses did not show a statistically significant association between PCOS and CAD (odds ratio [OR]: 0.99, 95% confidence interval [CI]: 0.89, 1.11). In contrast, genetically predicted BMI was statistically significantly associated with an increased odds of PCOS (OR: 3.21, 95% CI: 2.26, 4.56) and CAD (OR: 1.38, 95% CI: 1.14, 1.67). Similar results were obtained when secondary analyses were performed.

CONCLUSION

These sex-specific analyses show that the genetically predicted risk of PCOS is not associated with the risk of CAD. Instead, the genetically predicted risk of obesity (and its downstream metabolic effects) is the common denominator of both PCOS and CAD risk.

NAFLD-related gene polymorphisms and all-cause and cause-specific mortality in an Asian population: the Shanghai Changfeng Study

BACKGROUND

The PNPLA3 and TM6SF2 gene variants have been found to cause NAFLD with a favourable cardiovascular risk profile.

AIMS

To investigate the effects of the NAFLD risk alleles on the all-cause and cause-specific mortality in 5581 Chinese adults.

METHODS

The genome-wide genotypes were detected using a genotyping array and serum lipoprotein profiles were examined using 1H NMR platform. Liver fat content (LFC) was measured using a quantitative ultrasound method. The vital status was determined using official registration data.

RESULTS

Genome-wide association analysis showed that a series of variants in PNPLA3 were associated with LFC, including rs738409 C>G variant (P = 8.6 × 10^-7 ). Further analyses validated the associations of TM6SF2 rs58542926 C>T and MBOAT7 rs641738 C>T variants with NAFLD. During 29 425.1 person-years of follow-up, the overall mortality was 816 per 100 000 person-years, where 299 deaths were attributable to cardiovascular disease and 85 to liver disease. The PNPLA3 rs738409 C>G variant was independently associated with increased liver-specific mortality (P for trend = 0.034) but reduced cardiovascular mortality (P for trend = 0.047). A composite genetic-predisposition score of PNPLA3, TM6SF2, and MBOAT7 risk alleles presented similar opposite effects on liver-specific and cardiovascular mortality. Moreover, interactions of the NAFLD risk alleles with adiposity for liver-specific mortality were found (P_interaction  < 0.05). The reduced serum VLDL1 concentration was responsible for the increased liver-specific mortality related to NAFLD risk alleles.

CONCLUSION

The PNPLA3 rs738409 C>G variant and its combination with TM6SF2 rs58542926 C>T and MBOAT7 rs641738 C>T variants increase liver-specific mortality but reduce cardiovascular mortality in overweight/obese Chinese.

Hepatic Proteomics Analysis of Nonalcoholic Fatty Liver Disease Obese Rat Model After Short- and Long-Term Soy Protein Isolate Feeding

To identify possible mechanisms involved in the development and progression of nonalcoholic fatty liver disease (NAFLD), we conducted shotgun proteomics analysis on liver of obese Zucker rats fed either casein (CAS) or soy protein isolate (SPI) for 8 and 16 weeks. Rats (7 weeks old, n = 8-9/group) were randomly assigned to either a CAS-based or an SPI-based diet. Rats were killed after 8 or 16 weeks of feeding and livers were stored at -80°C. Ingenuity Pathway Analysis (IPA) software was used to facilitate interpretation of proteomics data. Predictions of activation or inhibition of molecules in the data were made based on activation z-score and P value of overlap (P < .05). Activation z-scores ≥2.0 indicate that a molecule is predicted to be activated, whereas activation z-scores of less than or equal to -2.0 indicate that a target molecule is predicted to be inhibited. Upstream regulator analysis with IPA revealed Neuregulin 1 (NRG1) to be the top activated protein in (z-score = 2.48, P < .05), and MKNK1 as the top inhibited protein (z-score = -2.83, P < .05) in SPI diet compared with CAS diet after both 8 and 16 weeks of SPI feeding. Regulator effects analysis also predicted that some proteins would be participating, directly or indirectly, in the inhibition of immune response functions (such as leukocyte migration) and lipid metabolism (such as synthesis of lipids) in SPI-fed rats relative to CAS-fed rats. Our results suggest that SPI diet modifies the expression of proteins that could be involved in the reduction of NAFLD.

Adipose tissue insulin resistance and lipidome alterations as the characterizing factors of non-alcoholic steatohepatitis

BACKGROUND

The prevalence of non-alcoholic fatty liver disease (NAFLD) is now 25% in the general population but increases to more than 55% in subjects with obesity and/or type 2 diabetes. Simple steatosis (NAFL) can develop into more severe forms, that is non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma leading to death.

METHODS

In this narrative review, we have discussed the current knowledge in the pathophysiology of fatty liver disease, including both metabolic and non-metabolic factors, insulin resistance, mitochondrial function, as well as the markers of liver damage, giving attention to the alterations in lipid metabolism and production of lipotoxic lipids.

RESULTS

Insulin resistance, particularly in the adipose tissue, is the main driver of NAFLD due to the excess release of fatty acids. Lipidome analyses have shown that several lipids, including DAGs and ceramides, and especially if they contain saturated lipids, act as bioactive compounds, toxic to the cells. Lipids can also affect mitochondrial function. Not only lipids, but also amino acid metabolism is impaired in NAFL/NASH, and some amino acids, as branched-chain and aromatic amino acids, glutamate, serine and glycine, have been linked to impaired metabolism, insulin resistance and severity of NAFLD and serine is a precursor of ceramides.

CONCLUSIONS

The measurement of lipotoxic species and adipose tissue dysfunction can help to identify individuals at risk of progression to NASH.

Effects of PNPLA3 I148M on hepatic lipid and very-low-density lipoprotein metabolism in humans

BACKGROUND

The phospholipase domain-containing 3 gene (PNPLA3)-148M variant is associated with liver steatosis but its influence on the metabolism of triglyceride-rich lipoproteins remains unclear. Here, we investigated the kinetics of large, triglyceride-rich very-low-density lipoprotein (VLDL), (VLDL₁ ), and smaller VLDL₂ in homozygotes for the PNPLA3-148M variant.

METHODS AND RESULTS

The kinetics of apolipoprotein (apo) B100 (apoB100) and triglyceride in VLDL subfractions were analysed in nine subjects homozygous for PNPLA3-148M and nine subjects homozygous for PNPLA3-148I (controls). Liver fat was >3-fold higher in the 148M subjects. Production rates for apoB100 and triglyceride in VLDL₁ did not differ significantly between the two groups. Likewise, production rates for VLDL₂ -apoB100 and -triglyceride, and fractional clearance rates for both apoB100 and triglyceride in VLDL₁ and VLDL₂ , were not significantly different.

CONCLUSIONS

Despite the higher liver fat content in PNPLA3 148M homozygotes, there was no increase in VLDL production. Equally, VLDL production was maintained at normal levels despite the putative impairment in cytosolic lipid hydrolysis in these subjects.

Metabolic biomarkers related to cardiac dysfunction in metabolic-dysfunction-associated fatty liver disease: a cross-sectional analysis

INTRODUCTION

Hepatic steatosis is associated with cardiac systolic and diastolic dysfunction. Therefore, we evaluated metabolites and their potential cardiovascular effects in metabolic-dysfunction-associated fatty liver disease (MAFLD).

MATERIALS AND METHODS

We conducted a cross-sectional study involving 75 participants (38 MAFLD and 37 controls). Hepatic steatosis was confirmed by hepatic ultrasonography and SteatoTestTM. Cardiac function was assessed using echocardiography. Metabolomic analysis was conducted using ultra-high-performance liquid chromatography-mass spectrometry.

RESULTS

The median age for participants' age was 45 (IQR 30-56.5), with gender distribution of 35 males and 40 females. MAFLD patients had lower levels of glycyl tyrosine (p-value < 0.001), lysophosphatidylcholine (LPC) (18:2/0:0) (p-value < 0.001), LPC (22:6) (p-value < 0.001), and ceramide (Cer) (d18:0/23:0) (p-value 0.003) compared to controls. MAFLD patients presented lower left ventricular ejection fraction (LVEF), E/A ratio, E/e' ratio, and average global longitudinal strain (GLS) values, with a p-value of 0.047, <0.001, 0.008, and <0.001, respectively. Decreased glycyl tyrosine levels were significantly correlated with reduced LVEF, even after performing multiple linear regression with 95% CI (1.34-3.394, p-value < 0.001). Moreover, decreased LPC (18:2/0:0) levels remained significantly associated with E/A ratio, even after adjusting for confounding factors with 95% CI (0.008-0.258, p-value = 0.042).

CONCLUSION

MAFLD patients are at risk for developing cardiac systolic and subclinical systolic dysfunctions, as well as diastolic dysfunction. Decreased glycyl tyrosine levels correlate with reduced LVEF and LPC (18:2/0:0) levels with diastolic dysfunction, even after adjusting for confounding factors, suggesting their potential to be used as metabolic biomarkers in detecting cardiovascular risk.

Cardiovascular Diseases and Non-Alcoholic Fatty Liver Disease: Relationship and Pathogenetic Aspects of Pharmacotherapy

The association of non-alcoholic fatty liver disease (NAFLD) and cardiovascular risk is currently one of the actively studied areas. The incidence of non-alcoholic fatty  liver disease continues to grow worldwide. In the structure of mortality rate of patients with non-alcoholic fatty  liver disease,  the first place is occupied by cardiovascular events: stroke and myocardial infarction. Studies have shown that the presence of severe liver fibrosis (F3-4) in NAFLD not only increases the risk of cardiovascular diseases (CVD), but also increases the risk  of  overall  mortality  by  69%  due  to mortality from cardiovascular causes. The degree of increased risk is associated with the degree of activity of non-alcoholic steatohepatitis (NASH). Despite the large number of works on this topic, we do not have a clear opinion on the impact on cardiovascular risk, interaction and the contribution of various factors, as well as algorithms for managing patients with non-alcoholic fatty liver disease to reduce the risk of cardiovascular diseases. This article describes the pathogenetic factors of formation of cardiovascular risks in patients with non-alcoholic fatty liver disease, proposed the idea of stratification of cardiovascular risks in these patients, taking into account changes in the structure of the liver (fibrosis) and function (clinical and biochemical activity) and also it describes the main directions of drug therapy, taking into account the common pathogenetic mechanisms for non-alcoholic fatty liver disease and cardiovascular diseases. The role of obesity, local fat depots, adipokines, and endothelial dysfunction as the leading pathogenetic factors of increased cardiovascular risk in patients with NAFLD is discussed. Among pathogenetically justified drugs in conditions of poly and comorbidity, hypolipidemic (statins, fibrates), angiotensin II receptor antagonists, beta-blockers, etc. can be considered. According to numerous studies, it becomes obvious that the assessment of cardiovascular risks in patients with NAFLD will probably allow prescribing cardiological drugs, selecting individualized therapy regimens, taking into account the form of NAFLD, and on the other hand, building curation taking into account the identified cardiovascular risks.

The use of screening tools for cardiovascular risk assessment in psoriasis – A case- control study

Background:

Psoriasis is a common, T-cell-mediated disease, affecting 0.44–2.8% of the general population in India. It is associated with a higher risk of cardiovascular disease possibly due to chronic inflammation. Those patients with severe psoriasis are at a higher risk of death due to cardiovascular disease. The use of scoring tools may help the care providers to assess cardiovascular risks in these patients.

Aims:

The aim of this study was to assess the cardiovascular risks in patients with severe psoriasis using the commonly used risk-assessment tools (Framingham risk score [FRS] and Pooled cohort equations [PCE]) and to understand the utility of these tools in practice.

Methods:

It is a case-control study performed in the dermatology outpatient department of a tertiary care center during the study period from January to December 2020. Consenting adults with chronic plaque psoriasis and psoriasis area and severity index (PASI) more than 10 were included in the study. The FRS and PCE risk scores were calculated for the patients and age- and sex-matched healthy controls.

Results:

A total of 213 patients were assessed and 30 patients were excluded. Of the 183 patients, 152 patients were assessed using FRS and 135 patients using PCE. Equal number of age- and sex-matched healthy controls were also assessed. The mean age of the patients assessed using the FRS and PCE was 47 ± 10.9 and 52.84 ± 8.9 years, respectively. The mean age of the controls was 45.52 ± 8.7 and 51.76 ± 8.1 years in the FRS and PCE groups, respectively. The male to female ratio was 1.92:1 and 2:1 in the FRS and PCE risk-score groups, respectively. The mean PASI score was 16.45 ± 7.88 and 15.6 ± 7.6 in the two groups, respectively. The 10-year risk estimate using FRS in the patients ranged from 0 to 26.9%. The mean and median estimates were 4.95 ± 5.7 and 2.8%, respectively, while 2.65 ± 4.7 and 0.8% in the controls (P = 0.001). The 10-year risk estimate in the patients using the PCE risk score ranged from 0.3 to 39.6%. The mean and median estimate in the patients was 8.17 ± 9.9 and 5.2%, respectively while they were 5.68 ± 7.5% and 2.6% in the controls (P = 0.024). The agreement between the FRS and PCE was found to be poor (Ϗ, 0.049). There was no statistically significant correlation of PASI to either the PCE risk score (P = 0.498) or FRS (P = 0.630).

Limitations:

A small sample size, and study in a tertiary care center may have resulted in sampling bias.

Conclusion:

Psoriasis is associated with a higher risk of cardiovascular disease. These tools may help a dermatologist in the primary prevention of cardiovascular disease. It can also help in the awareness of the increased risk of cardiovascular disease in patients.