Non-alcoholic fatty liver disease: a metabolic burden promoting atherosclerosis

From MASLD to PAD: Looking for Cardiovascular Disease Starting from Metabolic Status

Background: Peripheral artery disease (PAD) is still the least studied and evaluated form in clinical practice among atherosclerotic pathologies, despite the increased mortality and comorbidities related to it. The relationship between steatotic liver disease and an increased risk of cardiovascular disease has been extensively documented. Methods: The purpose of this work is to perform a review of the evidence linking NAFLD or MASLD to PAD, and examine possible clinical scenarios that arise from this new terminology. Results: The new definition of metabolic dysfunction-associated steatotic liver disease (MASLD) includes the presence of cardiometabolic risk factors and hepatic steatosis without any other underlying causes of hepatic steatosis; this terminology, coined in the hepatological field, could generate confusion, especially in the initial stages of its diffusion and among different medical specialists. Conclusions: Some recent data in the literature have strengthened the evidence of a pathological link between hepatic metabolic alteration (NAFLD or MAFLD) and PAD.

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.

Gallic Acid Can Promote Low-Density Lipoprotein Uptake in HepG2 Cells via Increasing Low-Density Lipoprotein Receptor Accumulation

Gallic acid (GA) is a type of polyphenolic compound that can be found in a range of fruits, vegetables, and tea. Although it has been confirmed it improves non-alcoholic fatty liver disease (NAFLD), it is still unknown whether GA can improve the occurrence of NAFLD by increasing the low-density lipoprotein receptor (LDLR) accumulation and alleviating cholesterol metabolism disorders. Therefore, the present study explored the effect of GA on LDLR and its mechanism of action. The findings indicated that the increase in LDLR accumulation in HepG2 cells induced by GA was associated with the stimulation of the epidermal growth factor receptor-extracellular regulated protein kinase (EGFR-ERK1/2) signaling pathway. When the pathway was inhibited by EGFR mab cetuximab, it was observed that the activation of the EGFR-ERK1/2 signaling pathway induced by GA was also blocked. At the same time, the accumulation of LDLR protein and the uptake of LDL were also suppressed. Additionally, GA can also promote the accumulation of forkhead box O3 (FOXO3) and suppress the accumulation of hepatocyte nuclear factor-1α (HNF1α), leading to the inhibition of proprotein convertase subtilisin/kexin 9 (PCSK9) mRNA expression and protein accumulation. This ultimately results in increased LDLR protein accumulation and enhanced uptake of LDL in cells. In summary, the present study revealed the potential mechanism of GA's role in ameliorating NAFLD, with a view of providing a theoretical basis for the dietary supplementation of GA.

Association Between Metabolic Dysfunction-Associated Fatty Liver Disease and MACCEs in Patients with Diabetic Foot Ulcers: An Ambispective Longitudinal Cohort Study

Aim

Metabolic dysfunction-related fatty liver disease (MAFLD) is closely related to metabolic disorders. However, the relationship between MAFLD and the prognosis in diabetic foot ulcers (DFUs) remains unclear. This study aimed to explore the association between MAFLD and the risk of major adverse cardiac and cerebral events (MACCEs) in patients with DFUs.

Methods

889 inpatients with DFUs (PEDIS/TEXAS mild and above) were included in this study from 2013 to 2023. All participants were placed into non-MAFLD (n = 643) and MAFLD (n = 246) groups and followed up every 6 months for 10.9 years with a median of 63 months through in-person outpatient interviews and family fixed-line telephone visits. The association between MAFLD and the risk of MACCEs was evaluated through Multivariate Cox regression analyses, Stratified analyses and Kaplan-Meier survival analyses.

Results

Of the 889 subjects, 214 (24.07%) experienced MACCEs. Multivariate Cox regression analysis showed that MAFLD was independently associated with MACCEs (P < 0.001), of which with non-fatal myocardial infarction (P = 0.04), non-fatal stroke (P = 0.047), coronary artery revascularization (P = 0.002), heart failure (P = 0.029), and all-cause mortality (P = 0.021), respectively. The stratified analysis revealed that compared with non-MAFLD (HR=1), DFUs with MAFLD had a 2.64-fold increased risk for MACCEs (P <0.001; P for interaction = 0.001) in peripheral arterial disease (PAD) subgroup. Kaplan-Meier analysis evidenced that the MAFLD group had a higher cumulative incidence of MACCEs (log-rank, all P < 0.05).

Conclusion

MAFLD is a high-risk factor for MACCEs in patients with DFUs. The findings will remind clinicians to pay more attention to MAFLD in patients with DFUs, especially in patients with DFUs combined with PAD as early as possible in clinical practice and adopt timely effective intervention strategies to prevent the occurrence of MACCEs to improve the clinical prognosis in patients with DFUs.

CETP-derived Peptide Seq-1, the Key Component of HB-ATV-8 Vaccine Prevents Stress Responses, and Promotes Downregulation of Pro-Fibrotic Genes in Hepatocytes and Stellate Cells

BACKGROUND

The nasal vaccine HB-ATV-8 has emerged as a promising approach for NAFLD (non-alcoholic fatty liver disease) and atherosclerosis prevention. HB-ATV-8 contains peptide seq-1 derived from the carboxy-end of the Cholesteryl Ester Transfer Protein (CETP), shown to reduce liver fibrosis, inflammation, and atherosclerotic plaque formation in animal models. Beyond the fact that this vaccine induces B-cell lymphocytes to code for antibodies against the seq-1 sequence, inhibiting CETP's cholesterol transfer activity, we have hypothesized that beyond the modulation of CETP activity carried out by neutralizing antibodies, the observed molecular effects may also correspond to the direct action of peptide seq-1 on diverse cellular systems and molecular features involved in the development of liver fibrosis.

METHODS

The HepG2 hepatoma-derived cell line was employed to establish an in vitro steatosis model. To obtain a conditioned cell medium to be used with hepatic stellate cell (HSC) cultures, HepG2 cells were exposed to fatty acids or fatty acids plus peptide seq-1, and the culture medium was collected. Gene regulation of COL1A1, ACTA2, TGF-β, and the expression of proteins COL1A1, MMP-2, and TIMP-2 were studied.

AIM

To establish an in vitro steatosis model employing HepG2 cells that mimics molecular processes observed in vivo during the onset of liver fibrosis. To evaluate the effect of peptide Seq-1 on lipid accumulation and pro-fibrotic responses. To study the effect of Seq-1-treated steatotic HepG2 cell supernatants on lipid accumulation, oxidative stress, and pro-fibrotic responses in HSC.

RESULTS AND CONCLUSION

Peptide seq-1-treated HepG2 cells show a downregulation of COLIA1, ACTA2, and TGF-β genes, and a decreased expression of proteins such as COL1A1, MMP-2, and TIMP-2, associated with the remodeling of extracellular matrix components. The same results are observed when HSCs are incubated with peptide Seq-1-treated steatotic HepG2 cell supernatants. The present study consolidates the nasal vaccine HB-ATV-8 as a new prospect in the treatment of NASH directly associated with the development of cardiovascular disease.

Association of metabolic dysfunction-associated fatty liver disease with systemic atherosclerosis: a community-based cross-sectional study

BACKGROUND

Data are limited on the association of metabolic dysfunction-associated fatty liver disease (MAFLD) with systemic atherosclerosis. This study aimed to examine the relationship between MAFLD and the extent of atherosclerotic plaques and stenosis, and presence of polyvascular disease (PolyVD).

METHODS

In this cross-sectional study, MAFLD was diagnosed based on the presence of metabolic dysfunction (MD) and fatty liver disease (FLD). MAFLD was divided into three subtypes: MAFLD with diabetes mellitus (DM), MAFLD with overweight or obesity (OW), as well as MAFLD with lean/normal weight and at least two metabolic abnormalities. Atherosclerosis was evaluated, with vascular magnetic resonance imaging for intracranial and extracranial arteries, thoracoabdominal computed tomography angiography for coronary, subclavian, aorta, renal, iliofemoral arteries, and ankle-brachial index for peripheral arteries. The extent of plaques and stenosis was defined according to the number of these eight vascular sites affected. PolyVD was defined as the presence of stenosis in at least two vascular sites.

RESULTS

This study included 3047 participants, with the mean age of 61.2 ± 6.7 years and 46.6% of male (n = 1420). After adjusting for potential confounders, MAFLD was associated with higher extent of plaques (cOR, 2.14, 95% CI 1.85-2.48) and stenosis (cOR, 1.47, 95% CI 1.26-1.71), and higher odds of presence of PolyVD (OR, 1.55, 95% CI 1.24-1.94) as compared with Non-MAFLD. In addition, DM-MAFLD and OW-MAFLD were associated with the extent of atherosclerotic plaques and stenosis, and presence of PolyVD (All P < 0.05). However, lean-MAFLD was only associated with the extent of atherosclerotic plaques (cOR, 1.63, 95% CI 1.14-2.34). As one component of MAFLD, FLD per se was associated with the extent of plaques and stenosis in participants with MAFLD. Furthermore, FLD interacted with MD to increase the odds of presence of systemic atherosclerosis (P for interaction ≤ 0.055).

CONCLUSIONS

MAFLD and its subtypes of DM-MAFLD and OW-MAFLD were associated with the extent of atherosclerotic plaques and stenosis, and presence of PolyVD. This study implicated that FLD might be a potential target of intervention for reducing the deleterious effects of MAFLD on systemic atherosclerosis.

Yao-Shan of traditional Chinese medicine: an old story for metabolic health

Type 2 diabetes mellitus, nonalcoholic fatty liver disease (NAFLD), cardio-cerebrovascular diseases (CCVDs), hyperuricemia and gout, and metabolic-related sexual dysfunction are metabolic diseases that affect human health in modern society. Scientists have made great efforts to investigate metabolic diseases using cell models in vitro or animal models in the past. However, the findings from cells or animals are difficult to translate into clinical applications due to factors such as the in vitro and in vivo differences; the differences in anatomy, physiology, and genetics between humans and animals; and the differences in microbiome-host interaction. The Chinese have extensively used the medicated diet of traditional Chinese medicine (TCM) (also named as Yao-Shan of TCM, Chinese Yao-Shan et al.) to maintain or improve cardiometabolic health for more than 2,200 years. These ancient classic diets of TCM are essential summaries of long-term life and clinical practices. Over the past 5 years, our group has made every effort to collect and sort out the classic Yao-Shan of TCM from the ancient TCM literature since Spring and Autumn and Warring States Period, especially these are involved in the prevention and treatment of metabolic diseases, such as diabetes, NAFLD, CCVDs, hyperuricemia and gout, and sexual dysfunction. Here, we summarized and discussed the classic Yao-Shan of TCM for metabolic diseases according to the time recorded in the ancient literature, and revised the Latin names of the raw materials in these Yao-Shan of TCM. Moreover, the modern medicine evidences of some Yao-Shan of TCM on metabolic diseases have also been summarized and emphasized in here. However, the exact composition (in terms of ratios), preparation process, and dosage of many Yao-Shan are not standardized, and their main active ingredients are vague. Uncovering the mystery of Yao-Shan of TCM through modern biological and chemical strategies will help us open a door, which is ancient but now looks new, to modulate metabolic homeostasis and diseases.

Linking Metallic Micronutrients and Toxic Xenobiotics to Atherosclerosis and Fatty Liver Disease-Postmortem ICP-MS Analysis of Selected Human Tissues

Dyslipidaemia is a disorder of the lipid metabolism, caused mainly by poor eating habits. The most severe consequence of an inappropriate diet is the development of atherosclerosis and hepatic steatosis. It is generally believed that a change in nutrition, and increased physical activity can eliminate these health problems. The contemporary research and therapies used to treat dyslipidemia mainly focus on lowering the triglyceride and cholesterol levels. However, disturbances in trace element homeostasis or the accumulation of toxic elements can also affect physiological processes, and be involved in the development of metabolically mediated diseases. The present study aimed to determine the mineral profiles of liver and brain tissues collected at autopsy (n = 39) in groups of people with hepatic steatosis (n = 5), atherosclerosis (n = 9), hepatic steatosis, and atherosclerosis (n = 16), and others without the selected disorders (n = 9). Concentrations of 51 elements were analysed via inductively coupled plasma mass spectrometry (ICP-MS) after the initial wet mineralisation of the samples with nitric acid. The results obtained allow us to conclude that the hepatic steatosis group suffers from a deficiency of important trace elements, such as copper, zinc, and molybdenum (p < 0.05), whereas the group with atherosclerosis is characterised by elevated levels of cadmium in the liver tissue (p = 0.01). Analysing the mean values of the element concentrations measured in 11 brain areas, statistically significant higher levels of calcium and copper (p < 0.001) were found in the atherosclerosis group, compared to the hepatic steatosis group, confirming the involvement of these elements in the pathogenesis of atherosclerosis. In addition, an accumulation of cadmium, lead, titanium, and strontium in the brain tissue was observed in the atherosclerosis group. While the accumulation of individual elements differs in different parts of the brain, the differences in the cadmium content (p < 0.05) between the study groups apply to the whole brain, except for the nucleus accumbens septi area, where a statistically significant titanium accumulation occurs in the atherosclerosis and steatosis groups, compared to the others (p < 0.05). In addition, the disruption of elemental homeostasis in the brain of a single case with bipolar disorder, and a case with hip replacement was observed. Our results confirm the involvement of chemical elements in the pathogenesis of selected metabolic diseases, and the need for further studies in larger populations.

The Role of Punicalagin and Its Metabolites in Atherosclerosis and Risk Factors Associated with the Disease

Atherosclerotic cardiovascular disease (ACVD) is the leading cause of death worldwide. Although current therapies, such as statins, have led to a marked reduction in morbidity and mortality from ACVD, they are associated with considerable residual risk for the disease together with various adverse side effects. Natural compounds are generally well-tolerated; a major recent goal has been to harness their full potential in the prevention and treatment of ACVD, either alone or together with existing pharmacotherapies. Punicalagin (PC) is the main polyphenol present in pomegranates and pomegranate juice and demonstrates many beneficial actions, including anti-inflammatory, antioxidant, and anti-atherogenic properties. The objective of this review is to inform on our current understanding of the pathogenesis of ACVD and the potential mechanisms underlying the beneficial actions of PC and its metabolites in the disease, including the attenuation of dyslipidemia, oxidative stress, endothelial cell dysfunction, foam cell formation, and inflammation mediated by cytokines and immune cells together with the regulation of proliferation and migration of vascular smooth muscle cells. Some of the anti-inflammatory and antioxidant properties of PC and its metabolites are due to their strong radical-scavenging activities. PC and its metabolites also inhibit the risk factors of atherosclerosis, including hyperlipidemia, diabetes mellitus, inflammation, hypertension, obesity, and non-alcoholic fatty liver disease. Despite the promising findings that have emerged from numerous in vitro, in vivo, and clinical studies, deeper mechanistic insights and large clinical trials are required to harness the full potential of PC and its metabolites in the prevention and treatment of ACVD.

Roles of the peroxisome proliferator-activated receptors (PPARs) in the pathogenesis of nonalcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) encompasses a spectrum of disease phenotypes which start with simple steatosis and lipid accumulation in the hepatocytes - a typical histological lesions characteristic. It may progress to non-alcoholic steatohepatitis (NASH) that is characterized by hepatic inflammation and/or fibrosis and subsequent onset of NAFLD-related cirrhosis and hepatocellular carcinoma (HCC). Due to the central role of the liver in metabolism, NAFLD is regarded as a result of and contribution to the metabolic abnormalities seen in the metabolic syndrome. Peroxisome proliferator-activated receptors (PPARs) has three subtypes, which govern the expression of genes responsible for energy metabolism, cellular development, inflammation, and differentiation. The agonists of PPARα, such as fenofibrate and clofibrate, have been used as lipid-lowering drugs in clinical practice. Thiazolidinediones (TZDs) - ligands of PPARγ, such as rosiglitazone and pioglitazone, are also used in the treatment of type 2 diabetes (T2D) with insulin resistance (IR). Increasing evidence suggests that PPARβ/δ agonists have potential therapeutic effects in improving insulin sensitivity and lipid metabolism disorders. In addition, PPARs ligands have been considered as potential therapeutic drugs for hypertension, atherosclerosis (AS) or diabetic nephropathy. Their crucial biological roles dictate the significance of PPARs-targeting in medical research and drug discovery. Here, it reviews the biological activities, ligand selectivity and biological functions of the PPARs family, and discusses the relationship between PPARs and the pathogenesis of NAFLD and metabolic syndrome. This will open new possibilities for PPARs application in medicine, and provide a new idea for the treatment of fatty liver and related diseases.

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

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

Analysis of the Genetic Relationship between Atherosclerosis and Non-Alcoholic Fatty Liver Disease through Biological Interaction Networks

Non-alcoholic fatty liver disease (NAFLD) seems to have some molecular links with atherosclerosis (ATH); however, the molecular pathways which connect both pathologies remain unexplored to date. The identification of common factors is of great interest to explore some therapeutic strategies to improve the outcomes for those affected patients. Differentially expressed genes (DEGs) for NAFLD and ATH were extracted from the GSE89632 and GSE100927 datasets, and common up- and downregulated DEGs were identified. Subsequently, a protein-protein interaction (PPI) network based on the common DEGs was performed. Functional modules were identified, and the hub genes were extracted. Then, a Gene Ontology (GO) and pathway analysis of common DEGs was performed. DEGs analysis in NAFLD and ATH showed 21 genes that were regulated similarly in both pathologies. The common DEGs with high centrality scores were ADAMTS1 and CEBPA which appeared to be down- and up-regulated in both disorders, respectively. For the analysis of functional modules, two modules were identified. The first one was oriented to post-translational protein modification, where ADAMTS1 and ADAMTS4 were identified, and the second one mainly related to the immune response, where CSF3 was identified. These factors could be key proteins with an important role in the NAFLD/ATH axis.

Iron Restriction Alleviates Atherosclerosis in ApoE KO Mice: An iTRAQ Proteomic Analysis

The "iron hypothesis" of atherosclerosis has long been controversial. Several studies have shown that dietary iron restriction or low-iron diets can effectively alleviate atherosclerosis in rabbits and mice. However, the underlying molecular mechanisms of these phenomena remain to be elucidated. In this study, we further evaluated possible correlations between a low-iron diet and atherosclerosis alleviation by using a quantitative proteomic approach. For this purpose, apolipoprotein E knockout (ApoE KO) mice were divided into three groups and fed a normal diet (ND), a high-fat diet (HFD), or a high-fat +low-iron diet (HFD + LI). Our results showed that the HFD-LI improved atherosclerosis by decreasing en face lesions of the aorta and reducing the accumulation of macrophages and disordered smooth muscle cells. HFD-LI also decreased iron levels, serum hepcidin levels and the serum concentration of low-density lipoprotein cholesterol (LDL-C). The use of the isobaric tag for absolute quantification (iTRAQ) proteomic method and subsequent multi-technique molecular validation indicated that many of the proteins involved in atherosclerotic inflammation, vascular remodeling, and focal adhesion had significant changes in their expression among the diet groups. Importantly, the proteins Gal-3 and VCAM1, which are key participants of atherosclerosis pathogenesis, revealed lower expression after a low-iron diet. The present findings widely support the "iron hypothesis" of atherosclerosis. Further studies are suggested to fully understand the implications of these results.

Canagliflozin Attenuates Hepatic Steatosis and Atherosclerosis Progression in Western Diet-Fed ApoE-Knockout Mice

Purpose

To investigate the effect of canagliflozin (20 mg/kg) on hepatic steatosis and atherosclerosis, and further to explore its possible mechanism.

Methods

Blood glucose, blood lipid, oxidative stress response and inflammatory cytokines were examined by intraperitoneal glucose tolerance test and ELISA assay. HE and Oil Red O staining were used to estimate the extent of hepatic steatosis and atherosclerosis. RNA-seq and qRT-PCR were used to further investigate the potential mechanism. The effects of canagliflozin on autophagy were detected using transmission electron microscopy and Western blotting. The endothelial function-related markers were determined by qRT-PCR.

Results

Canagliflozin notably alleviated the elevation in blood glucose and insulin resistance in western diet-fed ApoE-/- mice. In ApoE-/-+Cana group, ApoE-/- mice had lower levels of TG, TC, LDL-C, TNF-α, IL-6, IL-1β, and MCP-1. HE and Oil Red O staining presented that canagliflozin restrained the atherosclerotic plaque development and lipid accumulation. RNA-seq showed that 87 DEGs were relevant to improvement of hepatic steatosis and atherosclerosis by canagliflozin. Among them, CPS1, ASS1, ASL, ARG1, MATLA, GLS2, GOT1, SREBP1, Plin5, Retreg1, and C/EBPβ were verified. KEGG enrichment analysis indicated that DEGs were mainly involved in amino acid metabolism. Besides, we observed that canagliflozin reduced the contents of aspartic acid and citrulline in liver. Western blotting showed that ASS1 and p-AMPK/AMPK was remarkably elevated after administration of canagliflozin. Correspondingly, canagliflozin down-regulated SREBP1, FAS, ACC1, HMGCR, p-mTOR/m-TOR, p-ULK1/ULK1 and p62, but up-regulated CPT1, Beclin 1 and LC3 II/LC3I. TEM showed that canagliflozin reduced the number of lipid droplets and increased the autophagosomes. Moreover, we found that canagliflozin elevated the aortic endothelial function-associated markers including ASS1, ASL and eNOS.

Conclusion

Canagliflozin may attenuate hepatic steatosis by improving lipid metabolism, enhancing autophagy, and reducing inflammatory response through ASS1/AMPK pathway. Besides, canagliflozin further effectively improves the aortic endothelial function, thereby suppressing atherosclerosis development.

Novel metabolic classification for extrahepatic complication of metabolic associated fatty liver disease: A data-driven cluster analysis with international validation

BACKGROUND

Traditional classification systems of metabolic-associated fatty liver disease (MAFLD) do not account for the high rate of extrahepatic complications. To create a new classification of MAFLD using metabolic parameters to identify risks of complications more accurately.

METHODS

The retrospective study included MAFLD patients from the First Affiliated Hospital of Sun Yat-sen University for model development, and the model was validated respectively using Chinese cohort and UK Biobank database. Cluster analysis with k-means cluster was built using age, body mass index (BMI), glycosylated hemoglobin (HbA1c), total cholesterol/high density lipoprotein cholesterol (HDL-C) ratio, triglyceride, and lipoprotein(a) [Lp(a)] levels. Cox regression models were used to compare the risk of type 2 diabetes (T2DM), chronic heart disease (CHD), stroke and mortality between the clusters.

RESULTS

1038 MAFLD patients from cross-sectional population were recruited for the model derivation, with 10,451 cases (33.4 % of MAFLD) from Chinese cohort and 304,141 cases (34.9 % of MAFLD, 1010 cases with magnetic resonance imaging proton density fat fraction measurement [MRI-PDFF]) from the international cohort validated. Five replicable clusters of MAFLD patients were identified: Cluster 1(mild obesity and dyslipidemia-related), Cluster 2 (age related), Cluster 3 (severe insulin resistance-related), Cluster 4[high Lp(a)-related], and Cluster 5 (severe mixed hyperlipidemia-related). Patients in different clusters exhibited differences in the development of T2DM, CHD, stroke and all-causes mortality. Patients in Cluster 3 had significantly worst survival outcomes and higher risks of T2DM and CVD than those in other clusters.

CONCLUSION

The novel classification offers improved discrimination of new-onset MAFLD patients with different metabolic complications.

Aucubin administration suppresses STING signaling and mitigated high-fat diet-induced atherosclerosis and steatohepatosis in LDL receptor deficient mice

The rising obesity epidemic in developed countries is associated with many chronic inflammatory diseases including atherosclerosis and nonalcoholic steatohepatitis (NASH). Consuming aucubin may benefit health by suppressing inflammation. Herein, we studied the effects of aucubin consumption on atherosclerosis and NASH progression induced by high-fat diet (HFD) in LDL receptor deficient (LDLr^-/-) mice. Adult LDLr^-/- mice were fed with HFD for 12 weeks and received oral administration of aucubin for the last 6 weeks. Aucubin did not alter body weight or dyslipidemia, but lowered hyperglycemia and mitigated HFD-induced atherosclerosis and hepatic impairments in LDLr^-/- mice. Aucubin administration inhibited HFD-induced inflammation and downregulated mRNA and protein expression of stimulator of IFN genes (STING) in both aortas and livers of LDLr^-/- mice. In vitro, aucubin suppressed mitochondrial DNA (mtDNA)-induced activation of STING/NFκB pathway and downregulated gene expression of pro-inflammatory cytokines in cultured bone marrow-derived macrophages (BMDM). Furthermore, aucubin enhanced microRNA-181a-5p (miR-181a-5p) levels in both aortas and livers of LDLr^-/- mice. Importantly, miR-181a-5p mimicked the inhibitory effect of aucubin on STING/NFκB pathway and inflammation in BMDM. In conclusion, aucubin consumption attenuated HFD-induced atherosclerosis and NASH progression in LDLr^-/- mice, possibly through modulating miR-181a-5p/STING and inhibiting inflammation.

Impact of NAFLD and its pharmacotherapy on lipid profile and CVD

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of death worldwide. Increasing evidence suggests that, in addition to traditional metabolic risk factors such as obesity, hypercholesterolemia, hypertension, diabetes mellitus, and insulin resistance (IR), nonalcoholic fatty liver disease (NAFLD) is an emerging driver of ASCVD via multiple mechanisms, mainly by disrupting lipid metabolism. The lack of pharmaceutical treatment has spurred substantial investment in the research and development of NAFLD drugs. However, many reagents with promising therapeutic potential for NAFLD also have considerable impacts on the circulating lipid profile. In this review, we first summarize the mechanisms linking lipid dysregulation in NAFLD to the progression of ASCVD. Importantly, we highlight the potential risks of/benefits to ASCVD conferred by NAFLD pharmaceutical treatments and discuss potential strategies and next-generation drugs for treating NAFLD without the unwanted side effects.

Fibrosis-4 Index Is Closely Associated with Arterial Damage and Future Risk of Coronary Heart Disease in Type 2 Diabetes

This study evaluated the association between fibrosis-4 (FIB 4) index and arterial damage or future risk of coronary heart disease (CHD) in type 2 diabetes. The study subjects were 253 patients with type 2 diabetes. The FIB4 index, as a marker of hepatic fibrosis based on age, aspartate aminotransferase and alanine aminotransferase levels, and platelet count, was calculated for all subjects. Carotid intima-media thickness (IMT), carotid artery calcification (CAC), and aortic arch calcification (AAC) grade (0–2) were assessed as atherosclerotic variables. The Suita score was calculated as the future risk of coronary heart disease (CHD). We assessed whether the FIB4 index was associated with both atherosclerotic variables and the Suita score. FIB4 index was significantly associated with IMT (r = 0.241, $P<0.001$ ) and Suita score (r = 0.291, $P<0.001$ ). Subjects with CAC showed a significantly higher FIB4 index score compared to subjects without (1.70 ± 0.74 and 1.24 ± 0.69, respectively, $P<0.001$ ), whereas the FIB4 index was significantly elevated with a higher grade of AAC (1.24 ± 0.74, 1.56 ± 0.66, and 1.79 ± 0.71, respectively, $P<0.001$ ). Linear regression analysis adjusted for clinical characteristics indicated that the FIB4 index was positively associated with IMT, Suita score, CAC, and AAC grade (β = 0.241, $P=0.004$ ; β = 2.994, $P<0.001$ ; β = 0.139, $P=0.001$ ; and β = 0.265, $P<0.001$ , respectively). FIB4 index is closely associated with arterial damage and future risk of CHD in type 2 diabetes.

Association between the cardiometabolic index and non-alcoholic fatty liver disease: insights from a general population

Background

Emerging evidence suggests that cardiometabolic index (CMI) is closely related to diabetes, hypertension, stroke, cardiovascular disease, and kidney disease, which implies that CMI has the value as an indicator of metabolic diseases. However, data on the relationships between CMI and non-alcoholic fatty liver disease (NAFLD) risks have not been reported. This study is designed to examine the association between CMI and NAFLD in the general population.

Methods

The current study included 14,251 subjects whose CMI was the product of triglyceride/high-density lipoprotein cholesterol ratio and waist-to-height ratio. Linear regression was used to analyze the correlation between baseline information and CMI, logistic regression was used to study the relationship between CMI and NAFLD, and subgroup analysis was used to explore potential high-risk groups.

Results

After adjusted for potential confounding factors, higher CMI was independently associated with NAFLD, in which every additional standard deviation (SD) of CMI increased the risk of NAFLD by 28% (OR 1.28 per SD increase, 95% CI 1.19–1.37, P for trend < 0.0001). There were also significant differences in CMI-related NAFLD risk among different ages and genders, in which the CMI-related NAFLD risk in young people was significantly higher than that in other age groups (OR = 2.63 per SD increase for young people, OR = 1.38 per SD increase for young and middle-aged people, OR = 1.18 per SD increase for middle-aged and elderly people; OR = 1.14 per SD increase for elderly people, P for interaction = 0.0010), and the CMI-related NAFLD risk in women was significantly higher than that in men (OR = 1.58 per SD increase for women, OR = 1.26 per SD increase for men, P for interaction = 0.0045).

Conclusions

Current studies have found that after excluding potential confounding factors, higher CMI in the general population is independently associated with NAFLD risk.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02099-y.

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

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

Type 2 Diabetes Mellitus: A Pathophysiologic Perspective

Type 2 Diabetes Mellitus (T2DM) is characterized by chronically elevated blood glucose (hyperglycemia) and elevated blood insulin (hyperinsulinemia). When the blood glucose concentration is 100 milligrams/deciliter the bloodstream of an average adult contains about 5–10 grams of glucose. Carbohydrate-restricted diets have been used effectively to treat obesity and T2DM for over 100 years, and their effectiveness may simply be due to lowering the dietary contribution to glucose and insulin levels, which then leads to improvements in hyperglycemia and hyperinsulinemia. Treatments for T2DM that lead to improvements in glycemic control and reductions in blood insulin levels are sensible based on this pathophysiologic perspective. In this article, a pathophysiological argument for using carbohydrate restriction to treat T2DM will be made.

Dietary iron overload mitigates atherosclerosis in high-fat diet-fed apolipoprotein E knockout mice: Role of dysregulated hepatic fatty acid metabolism

The atherosclerosis "iron hypothesis" generates a fair amount of debate since it has been proposed. Here, we revisited the "iron hypothesis" by examining whether dietary iron overload would intensify iron deposition in plaques and thus lead to further exacerbation of atherosclerosis in apolipoprotein E knockout (ApoE KO) mice. ApoE KO mice were fed either a normal chow diet (ND) or a high fat diet (HFD) supplemented with or without 2% carbonyl iron (Fe) for 16 weeks. However, contrary to our assumption, dietary iron overloading did not intensify, but rather diminished the atherosclerotic lesion area by 65.3%, which was accompanied by significantly decreased serum total cholesterol, triglyceride and low-density lipoprotein cholesterol contents, together with hepatic lipid accumulation decline, despite the evident existence of aortic iron accumulation and the typical signs of iron overload in ApoE KO mice. Using isobaric tag for absolute quantification (iTRAQ) proteomics approach, hepatic CD36 and fatty acid binding proteins-mediated fatty acid (FA) uptake and trafficking impairment were identified as the key potential pathomechanisms by which iron overload diminishes atherosclerotic lesions. Furthermore, downstream hepatic FA de novo biosynthesis was enhanced and FA oxidation was inhibited to compensate for the FA deficiency triggered by iron overload-impaired fatty acid uptake and trafficking. Our findings suggested that dietary iron overload is not atherogenic in ApoE KO mice, and more research efforts are warranted to revisit the "iron hypothesis" of atherosclerosis.

Hepatocardiac or Cardiohepatic Interaction: From Traditional Chinese Medicine to Western Medicine

There is a close relationship between the liver and heart based on "zang-xiang theory," "five-element theory," and "five-zang/five-viscus/five-organ correlation theory" in the theoretical system of Traditional Chinese Medicine (TCM). Moreover, with the development of molecular biology, genetics, immunology, and others, the Modern Medicine indicates the existence of the essential interorgan communication between the liver and heart (the heart and liver). Anatomically and physiologically, the liver and heart are connected with each other primarily via "blood circulation." Pathologically, liver diseases can affect the heart; for example, patients with end-stage liver disease (liver failure/cirrhosis) may develop into "cirrhotic cardiomyopathy," and nonalcoholic fatty liver disease (NAFLD) may promote the development of cardiovascular diseases via multiple molecular mechanisms. In contrast, heart diseases can affect the liver, heart failure may lead to cardiogenic hypoxic hepatitis and cardiac cirrhosis, and atrial fibrillation (AF) markedly alters the hepatic gene expression profile and induces AF-related hypercoagulation. The heart can also influence liver metabolism via certain nonsecretory cardiac gene-mediated multiple signals. Moreover, organokines are essential mediators of organ crosstalk, e.g., cardiomyokines link the heart to the liver, while hepatokines link the liver to the heart. Therefore, both TCM and Western Medicine, and both the basic research studies and the clinical practices, all indicate that there exist essential "heart-liver axes" and "liver-heart axes." To investigate the organ interactions between the liver and heart (the heart and liver) will help us broaden and deepen our understanding of the pathogenesis of both liver and heart diseases, thus improving the strategies of prevention and treatment in the future.

Oxidative Stress in Non-alcoholic Fatty Liver Disease. An Updated Mini Review

Non-alcoholic fatty liver disease (NAFLD) is a challenging disease caused by multiple factors, which may partly explain why it remains still orphan of an adequate therapeutic strategy. Herein we focus on the interplay between oxidative stress (OS) and the other causal pathogenetic factors. Different reactive oxygen species (ROS) generators contribute to NAFLD inflammatory and fibrotic progression, which is quite strictly linked to the lipotoxic liver injury from fatty acids and/or a wide variety of their biologically active metabolites in the context of either a two-hit or a (more recent) multiple parallel hits theory. An antioxidant defense system is usually able to protect hepatic cells from damaging effects caused by ROS, including those produced into the gastrointestinal tract, i.e., by-products generated by usual cellular metabolic processes, normal or dysbiotic microbiota, and/or diet through an enhanced gut–liver axis. Oxidative stress originating from the imbalance between ROS generation and antioxidant defenses is under the influence of individual genetic and epigenetic factors as well. Healthy diet and physical activity have been shown to be effective on NAFLD also with antioxidant mechanisms, but compliance to these lifestyles is very low. Among several considered antioxidants, vitamin E has been particularly studied; however, data are still contradictory. Some studies with natural polyphenols proposed for NAFLD prevention and treatment are encouraging. Probiotics, prebiotics, diet, or fecal microbiota transplantation represent new therapeutic approaches targeting the gut microbiota dysbiosis. In the near future, precision medicine taking into consideration genetic or environmental epigenetic risk factors will likely assist in further selecting the treatment that could work best for a specific patient.

NAFLD and Cardiovascular Diseases: Epidemiological, Mechanistic and Therapeutic Considerations

Overwhelming evidence suggests an association of cardiovascular disease (CVD) with non-alcoholic fatty liver disease (NAFLD); however, the underlying mechanisms remain largely speculative. It is, however, likely that common mechanisms contribute to the development of CVD and NAFLD, with lifestyle factors such as smoking, sedentary lifestyle with poor nutrition habits and physical inactivity being major candidates. These behavioral factors, on a predisposing genetic background, trigger changes in gut microbiota, inflammation, dyslipidemia and oxidative stress, leading to metabolic syndrome, diabetes and obesity as well as atherosclerosis. Treatment options to counteract both the progression and development of CVD and NAFLD include lifestyle interventions, optimal medical therapy of comorbid conditions and, as final possibility, bariatric surgery. As no causal pharmacotherapy of NAFLD is available, further research is urgently needed to address the unmet need of a growing population with NAFLD and CVD.

CML/RAGE Signal Bridges a Common Pathogenesis Between Atherosclerosis and Non-alcoholic Fatty Liver

Non-alcoholic fatty liver disease (NAFLD) has become a common chronic disease in the world. NAFLD is not only a simple intrahepatic lesion, but also affects the occurrence of a variety of extrahepatic complications. In particular, cardiovascular complications are particularly serious, which is the main cause of death in patients with NAFLD. To study the relationship between NAFLD and AS may be a new way to improve the quality of life in patients with NAFLD. As we all known, inflammatory response plays an important role in the occurrence and development of NAFLD and AS. In this study, we found that the accumulation of Nε-carboxymethyllysine (CML) in the liver leads to hepatic steatosis. CML can induce the expression of interleukin (IL-1β), interleukin (IL-6), tumor necrosis factor (TNF-α), C-reactionprotein (CRP) by binding with advanced glycosylation end-product receptor (RAGE) and accelerate the development of AS. After silencing RAGE expression, the expression of pro-inflammatory cytokines was inhibited and liver and aorta pathological changes were relieved. In conclusion, CML/RAGE signal promotes the progression of non-alcoholic fatty liver disease and atherosclerosis. We hope to provide new ideas for the study of liver vascular dialogue in multi organ communication.