NAFLD: An Emerging Causal Factor for Cardiovascular Disease

The synergistic impact of type 2 diabetes and MASLD on cardiovascular, liver, diabetes-related and cancer outcomes

BACKGROUND AND AIMS

We examined the impact of a co-diagnosis of metabolic dysfunction-associated steatotic liver disease (MASLD) and type 2 diabetes (T2D) on patient outcomes.

METHODS

Using TriNetX, a global federated research network (n = 114 million), we undertook two retrospective cohort studies, using time-to-event analysis. Analysis 1 compared MASLD with T2D to MASLD alone; analysis 2 compared T2D with MASLD to T2D alone. Propensity score matching using greedy nearest neighbour (calliper .1) balanced the cohorts (1:1) for significant covariates. Primary outcomes were cardiovascular, liver, diabetes-related, and cancer events over 5 years.

RESULTS

Analysis 1 (n = 95 275): a co-diagnosis of T2D significantly increased the risk of ischaemic heart disease (IHD) (HR 1.39; CI: 1.34, 1.44), ischaemic stroke (HR 1.45; CI: 1.35, 1.56), heart failure (HR 1.42; CI: 1.36, 1.49), atrial fibrillation (HR 1.09; CI: 1.03, 1.16), hepatocellular carcinoma (HR 1.96; CI: 1.69, 2.27), pancreatic cancer (HR 1.25; CI: 1.06, 1.48) and liver-related complications over 5 years from MASLD diagnosis. Analysis 2 (n = 15 208): a co-diagnosis of MASLD significantly increased risk of all-cause mortality (HR 1.11; CI: 1.02, 1.22), IHD (HR 1.181; CI: 1.08, 1.29), hepatocellular (HR 50.31; CI: 6.94, 364.72), pancreatic (HR 1.78; CI: 1.12, 2.84), breast (HR 1.43; CI: 1.09, 1.88) and renal cancer (HR 2.01; CI: 1.24, 3.26), and diabetic neuropathy (HR 1.17; CI: 1.09, 1.27) over 5 years from metformin initiation.

CONCLUSIONS

T2D significantly potentiates the risk of cardiovascular, malignancy and liver-related outcomes in people with MASLD. The effect of MASLD on people with T2D, although less dramatic, still potentiated risk of death, IHD, malignancy and peripheral neuropathy.

Metabolic dysfunction-associated steatotic liver disease and atherosclerosis

PURPOSE OF REVIEW

To update information about the relationship between metabolic dysfunction-associated steatotic liver disease (MASLD) and atherosclerosis. This review emphasizes the potential mechanisms linking MASLD with atherosclerosis and the possible causal relationships between these conditions.

RECENT FINDINGS

An increased risk of cardiovascular disease is related to MASLD. Several molecular, cellular, and metabolic mechanisms have been described to explain the development of atherothrombosis in MASLD patients. These include atherogenic dyslipidemia, low-grade vascular inflammation, endothelial dysfunction, foam cell formation, proliferation of vascular smooth muscle cells, insulin resistance, gut microbiota dysbiosis, activation of renin-angiotensin and sympathetic nervous systems, hypercoagulability, and decreased fibrinolysis. Also, there is recent evidence suggesting an association between genetically driven liver fat and coronary heart disease mediated by the causal effect of apoB-containing lipoproteins. Several meta-analyses and systematic reviews have reported a strong association between MASLD and cardiovascular outcomes. MASLD is an important and independent risk factor for atherosclerosis development. Multiple mechanisms may be involved in this association. Further research is required to establish a causal association between MASLD and atherosclerosis.

Emerging Roles and Therapeutic Applications of Arachidonic Acid Pathways in Cardiometabolic Diseases

Cardiometabolic disease has become a major health burden worldwide, with sharply increasing prevalence but highly limited therapeutic interventions. Emerging evidence has revealed that arachidonic acid derivatives and pathway factors link metabolic disorders to cardiovascular risks and intimately participate in the progression and severity of cardiometabolic diseases. In this review, we systemically summarized and updated the biological functions of arachidonic acid pathways in cardiometabolic diseases, mainly focusing on heart failure, hypertension, atherosclerosis, nonalcoholic fatty liver disease, obesity, and diabetes. We further discussed the cellular and molecular mechanisms of arachidonic acid pathway-mediated regulation of cardiometabolic diseases and highlighted the emerging clinical advances to improve these pathological conditions by targeting arachidonic acid metabolites and pathway factors.

ATP Citrate Lyase Supports Cardiac Function and NAD+/NADH Balance And Is Depressed in Human Heart Failure

BACKGROUND

ATP-citrate lyase (ACLY) converts citrate into acetyl-CoA and oxaloacetate in the cytosol. It plays a prominent role in lipogenesis and fat accumulation coupled to excess glucose, and its inhibition is approved for treating hyperlipidemia. In RNAseq analysis of human failing myocardium, we found ACLY gene expression is reduced; however the impact this might have on cardiac function and/or metabolism has not been previously studied. As new ACLY inhibitors are in development for cancer and other disorders, such understanding has added importance.

METHODS

Cardiomyocytes, ex-vivo beating hearts, and in vivo hearts with ACLY inhibited by selective pharmacologic (BMS303141, ACLYi) or genetic suppression, were studied. Regulation of ACLY gene/protein expression, and effects of ACLYi on function, cytotoxicity, tricarboxylic acid (TCA)-cycle metabolism, and redox and NAD+/NADH balance were assessed. Mice with cardiac ACLY knockdown induced by AAV9-acly-shRNA or cardiomyocyte tamoxifen-inducible Acly knockdown were studied.

RESULTS

Acly gene expression was reduced more in obese patients with heart failure and preserved EF (HFpEF) than HF with reduced EF. In vivo pressure-overload and in vitro hormonal stress increased ACLY protein expression, whereas it declined upon fatty-acid exposure. Acute ACLYi (1-hr) dose-dependently induced cytotoxicity in adult and neonatal cardiomyocytes, and caused substantial reduction of systolic and diastolic function in myocytes and ex-vivo beating hearts. In the latter, ATP/ADP ratio also fell and lactate increased. U13C-glucose tracing revealed an ACLYdependent TCA-bypass circuit in myocytes, where citrate generated in mitochondria is transported to the cytosol, metabolized by ACLY and then converted to malate to re-enter mitochondria,bypassing several NADH-generating steps. ACLYi lowered NAD+/NADH ratio and restoring this balance ameliorated cardiomyocyte toxicity. Oxidative stress was undetected with ACLYi. Adult hearts following 8-weeks of reduced cardiac and/or cardiomyocyte ACLY downregulation exhibited ventricular dilation and reduced function that was prevented by NAD augmentation. Cardiac dysfunction from ACLY knockdown was worse in hearts subjected to sustained pressureoverload, supporting a role in stress responses.

CONCLUSIONS

ACLY supports normal cardiac function through maintenance of the NAD+/NADH balance and is upregulated by hemodynamic and hormonal stress, but depressed by lipid excess. ACLY levels are most reduced in human HFpEF with obesity potentially worsening cardio-metabolic reserve.

A Systematic Review of Statins for the Treatment of Nonalcoholic Steatohepatitis: Safety, Efficacy, and Mechanism of Action

Nonalcoholic fatty liver disease (NAFLD) is the liver component of a cluster of conditions, while its subtype, nonalcoholic steatohepatitis (NASH), emerges as a potentially progressive liver disorder that harbors the risk of evolving into cirrhosis and culminating in hepatocellular carcinoma (HCC). NASH and cardiovascular disease (CVD) have common risk factors, but compared to liver-related causes, the most common cause of death in NASH patients is CVD. Within the pharmacological armamentarium, statins, celebrated for their lipid-modulating prowess, have now garnered attention for their expansive therapeutic potential in NASH. Evidence from a plethora of studies suggests that statins not only manifest anti-inflammatory and antifibrotic properties but also impart a multifaceted beneficial impact on hepatic health. In this review, we used "statin", "NAFLD", "NASH", and "CVD" as the major keywords and conducted a literature search using the PubMed and Web of Science databases to determine the safety and efficacy of statins in patients and animals with NASH and NAFLD, and the mechanism of statin therapy for NASH. Simultaneously, we reviewed the important role of the intestinal microbiota in statin therapy for NASH, as it is hoped that statins will provide new insights into modulating the harmful inflammatory microbiota in the gut and reducing systemic inflammation in NASH patients.

TG: A Mediator of the Relationship of Serum Uric Acid to Creatinine Ratio and Nonalcoholic Fatty Liver Disease in Non-Obese Patients with Type 2 Diabetes

Background

The study estimated the association between NAFLD and SUA/Cr in Chinese non-obese patients with type 2 diabetes mellitus (T2DM) and also investigated mediating effect of TG.

Methods

All patients were divided into NAFLD group (n = 420) and non-NAFLD group (n = 347). The differences of biochemical indicators between the two groups were compared. The link between SUA/Cr and other parameters was checked through Spearman correlation analysis. Differences in the incidence rate of NAFLD between SUA/Cr and TG 3 tertile subgroups were tested by chi-squared. To explore the independent influence of SUA/Cr and TG on NAFLD, logistic regression was performed. The predictive value of SUA/Cr and SUA/Cr combined with BMI for NAFLD was analyzed using ROC curves. In addition, to confirm whether TG has a mediating effect on the link of SUA/Cr and NAFLD, we conducted a mediating analysis.

Results

NAFLD group had higher SUA/Cr values than individuals without NAFLD (P < 0.01). SUA/Cr was linked with TC and TG (r = 0.081, 0.215 respectively). NAFLD prevalence increased progressively from quartile 1 to quartile 3 of SUA/Cr (44% vs 57% vs 62%). Prevalence of NAFLD increased from quartile 1 to quartile 3 of TG (35.8% vs 58.7% vs 69.9%). Analysis of the logistic regression revealed that SUA/Cr and TG were statistically linked with NAFLD. The ROC curve pointed out that the area under the curve (AUC), sensitivity and specificity of SUA/Cr were 0.59, 0.629 and 0.522, respectively. The AUC, sensitivity and specificity for SUA/Cr combined with BMI were 0.719, 0.644 and 0.677, separately. The mediation analysis showed a statistically direct effect of SUA/Cr on NAFLD (β=0.148, 95% CI: 0.0393, 0.2585). The function of SUA/Cr on NAFLD partially mediated by TG (β=0.1571, 95% CI: 0.0704, 0.2869).

Conclusion

SUA/Cr was significantly associated with NAFLD in non-obese T2DM patients, and TG partially mediated this association. SUA/Cr can be applied to predict for NAFLD.

Genetic Variants Linked to Myocardial Infarction in Individuals with Non-Alcoholic Fatty Liver Disease and Their Potential Interaction with Dietary Patterns

In recent studies, non-alcoholic fatty liver disease (NAFLD) has been associated with a high risk of ischemic heart disease. This study aimed to investigate a genetic variant within a specific gene associated with myocardial infarction (MI) among patients with NAFLD. We included 57,205 participants from a Korean genome and epidemiology study. The baseline population consisted of 45,400 individuals, with 11,805 identified as patients with NAFLD. Genome-wide association studies were conducted for three groups: the entire sample, the healthy population, and patients with NAFLD. We defined the p-value < 1 × 10-5 as the nominal significance and the p-value < 5 × 10-2 as statistically significant for the gene-by-nutrient interaction. Among the significant single-nucleotide polymorphisms (SNPs), the lead SNP of each locus was further analyzed. In this cross-sectional study, a total of 1529 participants (2.8%) had experienced MI. Multivariable logistic regression was performed to evaluate the association of 102 SNPs across nine loci. Nine SNPs (rs11891202, rs2278549, rs13146480, rs17293047, rs184257317, rs183081683, rs1887427, rs146939423, and rs76662689) demonstrated an association with MI in the group with NAFLD Notably, the MI-associated SNP, rs134146480, located within the SORCS2 gene, known for its role in secreting insulin in islet cells, showed the most significant association with MI (p-value = 2.55 × 10-7). Our study identifies candidate genetic polymorphisms associated with NAFLD-related MI. These findings may serve as valuable indicators for estimating MI risk and for conducting future investigations into the underlying mechanisms of NAFLD-related MI.

Multispecies transcriptomics identifies SIKE as a MAPK repressor that prevents NASH progression

Nonalcoholic fatty liver (NAFL) remains relatively benign, but high-risk to end-stage liver diseases become highly prevalent when it progresses into nonalcoholic steatohepatitis (NASH). Our current understanding of the development of NAFL to NASH remains insufficient. In this study, we revealed MAP kinase (MAPK) activation as the most notable molecular signature associated with NASH progression across multiple species. Furthermore, we identified suppressor of IKKε (SIKE) as a conserved and potent negative controller of MAPK activation. Hepatocyte-specific overexpression of Sike prevented NASH progression in diet- and toxin-induced mouse NASH models. Mechanistically, SIKE directly interacted with TGF-β-activated kinase 1 (TAK1) and TAK1-binding protein 2 (TAB2) to interrupt their binding and subsequent TAK1-MAPK signaling activation. We found that indobufen markedly up-regulated SIKE expression and effectively improved NASH features in mice and macaques. These findings identify SIKE as a MAPK suppressor that prevents NASH progression and provide proof-of-concept evidence for targeting the SIKE-TAK1 axis as a potential NASH therapy.

Role of Perturbated Hemostasis in MASLD and Its Correlation with Adipokines

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) continues to rise, making it one of the most prevalent chronic liver disorders. MASLD encompasses a range of liver pathologies, from simple steatosis to metabolic dysfunction-associated steatohepatitis (MASH) with inflammation, hepatocyte damage, and fibrosis. Interestingly, the liver exhibits close intercommunication with fatty tissue. In fact, adipose tissue could contribute to the etiology and advancement of MASLD, acting as an endocrine organ that releases several hormones and cytokines, with the adipokines assuming a pivotal role. The levels of adipokines in the blood are altered in people with MASLD, and recent research has shed light on the crucial role played by adipokines in regulating energy expenditure, inflammation, and fibrosis in MASLD. However, MASLD disease is a multifaceted condition that affects various aspects of health beyond liver function, including its impact on hemostasis. The alterations in coagulation mechanisms and endothelial and platelet functions may play a role in the increased vulnerability and severity of MASLD. Therefore, more attention is being given to imbalanced adipokines as causative agents in causing disturbances in hemostasis in MASLD. Metabolic inflammation and hepatic injury are fundamental components of MASLD, and the interrelation between these biological components and the hemostasis pathway is delineated by reciprocal influences, as well as the induction of alterations. Adipokines have the potential to serve as the shared elements within this complex interrelationship. The objective of this review is to thoroughly examine the existing scientific knowledge on the impairment of hemostasis in MASLD and its connection with adipokines, with the aim of enhancing our comprehension of the disease.